Stockholm university

Anna TreydteAssociate professor, Docent

About me

I am an Associate Professor in Nature and Environmental Management, with a focus on Sustainable Development, here at the Department of Physical Geography.

My scientific interest lies in biodiversity and conservation challenges in a human-impacted, changing world. My main research focus lies in assessing how climate change and human activities alter structural, species and functional biodiversity of flora and fauna in natural and agro-ecological systems. I investigate plant-animal interactions and animal population management, human-wildlife coexistence and livestock impacts on rangelands across the world. I am interested in the shifts in nutrient cycling, carbon stocks as well as plant and animal species diversity and invasiveness in landscapes of various human land use pressure (e.g., corridors, buffer zones, protected lands and cultivated lands) that are also facing weather extremes triggered by climate change. I include socio-ecological aspects in my research as sustainable human-wildlife coexistence can only be achieved when local stakeholders are informed and participate in the decision-making process on resource use.

With my research projects, I address human-wildlife coexistence globally, particularly focusing on wild mammal species but also investigating livestock populations and their movement patterns in and around protected areas. My research spans across various spatial and temporal scales and addresses ecosystem functions and processes in temperate climates (Germany, Sweden, Italy), desert environments (Mongolia, Saudi Arabia), savanna systems (eastern and southern Africa), mountain regions (Andes) and tropical forests (China, Vietnam, Thailand, Tanzania).

 

Publications: https://scholar.google.com/citations?user=bOhIQlkAAAAJ&hl=en

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Teaching

Teaching:

2024 – present       Theory and Methods in Globalization, Environment and Global change, MSc-Module KG7229 (SU)

2023 – present       International Environmental Management, MSc-Module GE7084 (SU)

2022                     CIVIS – Transdisciplinary Course on Sustainability Science, based at University of Bucharest in collaboration with Stockholm University

2022                     CIVIS – Global Change Biology, based at Sapienzia University Rome in collaboration with Stockholm University

2021 – present       Political Ecology – Land use and natural resources in a local to global perspective, MSc-Module GE7081 (SU)

2021 – present       Landscape Ecology, MSc-Module GE7075 (SU)

2021 – present       Applied GIS analyses, MSc-Module GE7088 (SU)

2021 – 2022          Green Infrastructure, MSc-Module GE7077 (SU)

2023 – present       Earth Sciences and Sustainable Development, BSc-Module GE5042 (SU)

2021 – present       Natural Resources and Sustainable Development / Naturresurser och hållbar utveckling, BSc-Module GE 2024 (SU) – course responsible

2021 – present       Ecosystem Services Management / Ekosystemtjänstförvaltning, BSc-Module GE 2025 (SU) – course responsible

2021 – present       Sustainable Consumption, BSc-Module GE 2026 (SU)

MSc Theses:

2024 – present     I. Li: Habitat distribution analysis of wetlands for waterbirds in Sweden (SU)

2024 – present     S. Acosta: Modeling the distribution of invasive hippos in Colombia and understanding their impact on ecosystem services (SU)

2024 – present     A. Sommarström:  Woody encroachment of invasive Acacia mearnsii and related environmental factors in a South African rangeland (SU)

2024 – present     A. Sima: Burns and Bison: Plant biodiversity under various management regimes in Illinois Tallgrass Prairie (SU)

2024                    R. Mukkat: Eco-labelling criteria for promoting sustainability in C-Part products: a review (SU)

2024                    F. Fahim: Visualizing and analyzing unequal exchange conflicts of mineral ores and associated environmental justice in Sweden (SU)

2023 – present      J. Villing: Assessing the survival of tree seedlings planted for Carbon offsets by smallholder farmers in Tanzania (UHOH, ECHO East Africa)

2023 – present      L. Winkler: Socio-ecological conditions needed for restoring Tanzanian rangelands through seedbomb technology (UHOH, Savannas Forever, NM-AIST)

2023 – present      J. Eriksson: Home range connectivity and attitudes towards wolves on a landscape scale in Sweden (SU)

2023 – present     M. Augustin: Wolf – human coexistence: an example of policies and associated acceptance by the local communities in Poland (SU)

2023 – 2024        V. Josefsson: Assessing the effects of different management practices in cattle herding on soil properties and ground vegetation (SU, Rhodes University)

2023 –2024         L. Andersson: Seed bank distribution of Lupinus polyphyllus under different management regimes in Sweden (SU, DEEP)

2023 – 2024       A. Garnell: Plant species diversity and carbon stocks in salt marshes under different grazing regime (SU, DEEP)

2023                  P. Bhatnagar: Investigating Groundwater Depletion in Agra, Uttar Pradesh: Agroforestry as potential water management strategy    (SU)

2023                   A. Theorell: The potential environmental and health impacts by establishing a rare earth element mine in Kiruna, Sweden (SU)

2022 – 2023        H. Kjeldahl: Porpoise movement with respect to fishing activity and protected areas in the Kattegat area (SU, Natural History Museum)

2022 – 2023        L. Soliz: Shrub encroachment in savanna systems based on the ground water table and soil moisture availability (SU, NM-AIST)

2022 – 2024        F. Vikinger: Are reindeer afraid of tourists? Movement patterns of reindeer in northern Sweden (SU, Swedish Agricultural University)

2022 – 2023        M. Mischke: Herder and livestock movements in search for water sources in the Mongolian steppe (SU, UHOH)

2022 – 2023        Y. Aurell: Land take and reuse in the city of Uppsala, Sweden (Stockholm University)

2019 – 2023        J. Sanare: Human-elephant interactions and community attitudes in Kitendeni Wildlife Corridor, Tanzania (NM-AIST, Nordanglia, AridLands)

2021 – 2022        J. Dietz: Scenario-based land use/cover change and impacts on forest carbon stocks in Zambia (SU, Thuenen Institute for Forestry and Forest Economics)

2021 – 2022        A. Lindahl: Inventory of invasive plant species Lupinus polyphyllus in Dalarna county (Sweden) and its effects on pollinator diversity (Stockholm University)

2019 – 2022        S. Adiel: Assessment of Artemisia annua to control Invasive Gutenbergia cordifolia at Mwiba Game Ranch in the Greater Serengeti ecosystem (NM-AIST, Friedkin Foundation)

2019 – 2021        M. Michael: How does natural plant extract treatment against the alien invasive Gutenbergia cordifolia affect the diversity and foraging behavior of flower visiting insects in Ngorongoro, Tanzania? (NM-AIST, Friedkin Foundation)

2019 – 2020        J. Ploechl: Herders’ traditional knowledge and rangeland management as climate adaption strategy in the Enduimet Wildlife Management Area, Northern Tanzania (NM-AIST, Nordanglia, UHOH)

2018 – 2021        N. Felix: Effects of retaliatory killing on the dynamics of male lion coalitions: a case study in Tarangire Manyara Ecosystem (NM-AIST, TAWIRI)

2018 – 2021        A. Asenga: Spatial component of woody encroachment: impacts on plant functional groups and predators (NM-AIST, MaswaGR)

2018 – 2021        G. Nchimbi: Re-colonization of flora and fauna in the post mining area of Lake Manyara National Park, Tanzania (NM-AIST, TANAPA)

2018 – 2020        W. Kananga: Managing the invasive plant Parthenium hysterophorus and its socio-economic impact on local communities in Arusha, Tanzania (NM-AIST, TPRI)

2017 – 2019        S. Dror: Assessing the interaction between Asian elephants (Elephas maximus) and Asian honey bees (Apis cerana indica) (UHOH, King Mongkuts University)

2017 – 2019        H. Kimaro: The dynamics of bush encroachment through Acacia drepanolobium  in the Mara Region, Tanzania (NM-AIST, Wake Forest University)

2017 – 2019        J. Lyakurwa: How humans impact the habitat structure for reptiles in the Uzungwa Scarp Forest Reserve (NM-AIST)

2017 – 2019        A. Baltazary: Wildlife-livestock interaction: is the feeding behaviour of wildlife influenced by livestock? (NM-AIST, Norwegian Technical University)

2017 – 2018       E. Gerhard: Wildlife-friendly cocoa production: Assessing potential management strategies (UHOH, University of Ghana)

2017 – 2018        T. Sukic: Comparing invasive success of the plant species Parthenium hysterophorus in- and outside the Kruger National Park, South Africa (UHOH, Scientific Services South Africa)

2016 – 2017        H. Hayat: Wildlife - livestock interaction in the contractual Richtersveld National Park, South Africa (UHOH, Coventry University)

2014 – 2015        A. Manas: Assessing the potential of wildlife corridors as mitigation measures for human-elephant conflicts in rubber-dominated landscapes (UHOH)

2013                   M. Jung: Farmer´s perspective of human-wildlife conflicts around the Tai Rom Yen protected area, southern Thailand (UHOH)

2013                   K. Aidoo: GIS based land use mapping of small-scale farming adjacent to rubber cultivations in southern Thailand (UHOH)

2012 – 2013        M. Sandalj: Consumption and trade of wild meat in Thua Thien Hue province, Vietnam (UHOH, TRAFFIC - WWF Vietnam)

2011 – 2012        L. Atanga: Assessing the sustainability of different livestock production systems of small farm holders in Gewane district, Afar region, Ethiopia (UHOH, Institute of Social and Institutional Change in Agricultural Development).

2010 – 2012        S. Baumgartner: Wildlife and livestock herbivory shaping woody and grassy vegetation species composition and nutrients in a South African Savanna (UHOH)

2010 – 2011        F. Harich: The effects of human-wildlife conflicts on food security around the Bia Conservation Area, Ghana (UHOH, University of Ghana)

2010 – 2012        P. Trumpf: Human-wildlife conflicts in and around the Naban River Watershed National Nature Reserve, Yunnan, China (UHOH)

2008 – 2009        S. Ikenoue: The effect of the land reform on land use pattern change in Limpopo Province, South Africa (UHOH and South African Environmental Observation Network (SAEON)).

2006 – 2007        J. van der Beek and J. Perdok: Enhanced use of beneath-canopy vegetation by grazing ungulates in African savannahs (Wageningen University, SANPARKS)

2007                   F. Looringh van Beeck: Improved beneath-crown grass quality in South African savannas (Wageningen University)

2004                   S.A. Halsdorf: Habitat use of the common warthog Phacochoerus africanus on a former cattle ranch in Tanzania (ETH Zürich)

BSc theses:

2024                 T. Nilsson Häll: Rains without rainbows - flood risk and vulnerability of transgender communities in Kenya (SU)

2024                 A. Åslund: Effects of conservation measures on the endangered Alcon blue butterfly Phengaris alcon population in Sweden (SU)

2024                 H. Pulls: Possible reasons to the recent decline of the Ural owl (Strix uralensis) population in Sweden (SU)

2023                 C. Corman: Bicycle infrastructure in a European urban context (SU)

2022                 E. Palmertz: Spatial modeling of soil erosion and identification of high-risk spots with the GIS-RUSLE model for lake Vättern, Sweden (SU)

2022                 E. Fransson: It can never be worse than now-A qualitative study of mining related conflicts in Sápmi from a Sámi perspective (SU)

2009 – 2010      N. Österle: Assessment of livestock keeping practices and manure use under varying environmental and socio-economic constraints in Southern Ethiopia (UHOH, Hawassa University)

2009                 J. Mück: Konflikte mit Schwarzwild und Analyse von Wildschäden in Baden-Württemberg (UHOH)

Research

My research addresses the following questions:

  • How do plants and animals respond to human impact in protected and cultivated landscapes?
  • How can we maintain biodiversity in times of global and /or climate change?
  • What solutions are environmentally sustainable? What is socio-economically sustainable?
  • How passive / active should we be when restoring ecological functions and services in rangelands?

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Below are the various research projects that I am leading:

 

HUMAN-WILDLIFE COEXISTENCE

Human – Wildlife Coexistence: Reaching a sustainable human – wildlife coexistence by understanding patterns, predicting conflict hotspots and improving communication

Members: Ronja Kraus, PhD student (https://www.su.se/english/profiles/rokr4514-1.591101); Erica von Essen, co-supervisor (https://www.slu.se/cv/erica-von-essen); Anna Sustersic, co-supervisor (https://www.coexistence.life/team/)

We intend to map human-wildlife conflicts on a large scale, with case study sites in Sweden, Italy and Tanzania. We will use data on conflict occurrences, wildlife population trends and movement patterns as well as socio-ecological drivers to understand the dynamics between human and wildlife land use over space and time. Using Agent based modelling we plan to draw a landscape of acceptance in the human-dominated land around protected areas.

Intended year of graduation: Year 2026, at Stockholm University, Sweden

Funding: Stockholm University

Publications: not yet

Link: https://www.su.se/forskning/forskningsprojekt/ng-att-uppn%C3%A5-en-h%C3%A5llbar-samexistens-mellan-m%C3%A4nniskor-och-rovdjur-i-ett-socio-milj%C3%B6v%C3%A4nligt-landskap

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Human – Wildlife Coexistence: Striking a Balance: Navigating Human-Carnivore Conflicts Around Ruaha National Park in Tanzania

 

Members: Maximilian Mgimba, PhD student; Francis Moyo, co-supervisor (https://nm-aist.ac.tz/teams/dr-francis-moyo/); Naza Mbaga, co-supervisor (https://www.researchgate.net/profile/Naza-Mmbaga)

We investigate the drivers of human wildlife conflicts and assess the effectiveness of management approaches around Ruaha National Park. Through literature reviews and large-scale interview data we try to understand spatio-temporal patterns in conflict locations and assess which conflict mitigation or prevention tools work best.

Intended year of graduation: Year 2026, at NM-AIST, Tanzania

Funding: NM-AIST, in collaboration with Lion Landscapes (https://www.lionlandscapes.org/research)

Publications: not yet

Link: -

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RANGELAND PROTECTION

Rangeland Ecology: Adapting to change – co-management scenarios of local pastoralists and protected area management to maintain cultural and biological diversity in the Dzungarian Gobi, Mongolia

Members: Lena Michler, PhD student (https://agroecology.uni-hohenheim.de/michler); Max Mischke, MSc student at Stockholm University; Marie-Louise Schmitt, BSc student at University of Hohenheim; Petra Kaczensky, co-supervisor (https://www.inn.no/english/find-an-employee/petra-kaczensky.html)

Here we focus on the biological and cultural diversity in the Dzungarian Gobi desert in Mongolia, where nomadic pastoralists roam with their herds of goats, sheep and other livestock, sharing the natural resources with wild ungulates. We investigate livestock movement patterns using GPS collars and conduct surveys on the traditional nomadic herding management. We apply a socio-ecological approach, including field observations, laboratory experiments and collecting interview data.

Lena is also employed in a 50% position as Project Lead Socio-Economy at the International Takhi Group (ITG), directly supporting the protected area management with her research outcomes (www.savethewildhorse.org).

Intended date of graduation: Year 2024, at the University of Hohenheim, Stuttgart, Germany

Funding: Heinrich Boell Stiftung, Germany; ITG Switzerland

Related publications:

Michler LM, Kaczensky P, Batsukh D, Treydte AC (2024) What will the future bring? – Socio-economic challenges to herder households in the Dzungarian Gobi, Mongolia. Preprint: https://doi.org/10.21203/rs.3.rs-4743895/v1  

Michler LM, Kaczensky P, Oyunsaikhan G, Bartzke GS, Devineau O, Treydte AC (2023) To move or not to move—factors influencing small-scale herder and livestock movements in the Dzungarian Gobi, Mongolia. Regional Environmental Change 23: p.131. https://doi.org/10.1007/s10113-023-02126-y

Michler LM, Kaczensky P, Ploechl JF, Batsukh D, Baumgartner SA, Battogtokh B, Treydte AC (2022) Moving toward the greener side: environmental aspects guiding pastoral mobility and impacting vegetation in the Dzungarian Gobi, Mongolia. Rangeland Ecology & Management 83:149-160. https://doi.org/10.1016/j.rama.2022.03.006

Michler LM, Treydte AC, Hayat H, Lemke S (2019) Marginalised herders: Social dynamics and natural resource use in the fragile environment of the Richtersveld National Park, South Africa. Environmental Development 29:29-43. https://doi.org/10.1016/j.envdev.2018.12.001

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Rangeland Ecology: Pyrodiversity affecting plant species communities in the Serengeti ecosystem

Members: Louis Hunninck, post-doc (https://www.researchgate.net/profile/Louis-Hunninck); Stuart Smith, collaborator (https://research.brighton.ac.uk/en/persons/stuart-smith); John Bukombe, collaborator (https://www.researchgate.net/profile/Bukombe-John)

Here, we assess how fire frequency, timing, intensity, and size affect the distributions of herbaceous species across the Serengeti ecosystem, Tanzania. We compile a unique herbaceous dataset from 20 projects spanning two decades, containing more than 450 surveyed herbaceous species and over 11,000 recorded species presence locations. We apply joint species distribution models using the Hierarchical Modelling of Species Communities (HMSC) approach, which incorporates species phylogeny and species co-occurrence to better inform how species distributions relate to environmental variables. We consider both environmental (e.g., mean annual rainfall) and anthropogenic disturbance covariates (e.g., distance to roads).

Intended end of project: Year 2024

Funding: Stockholm University

Related publications: not yet

Link: https://www.su.se/forskning/forskningsprojekt/ng-f%C3%B6rst%C3%A5else-av-hur-branddiversitet-p%C3%A5verkar-v%C3%A4xtartssamh%C3%A4llen-i-serengeti-ekosystemet

 

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Rangeland Management: How resilient are semi-arid rangelands towards high grazing pressure and rainfall variability? Water and nutrient availability under different grazing regimes in eastern Africa

 

Members: Sabine Baumgartner, PhD student (https://agroecology.uni-hohenheim.de/baumgartner); Stuart Smith, collaborator (https://www.hutton.ac.uk/people/stuart-smith/)

This research focuses on understanding traditional herding strategies, in particular the use of long-time exclosures and seasonal grazing grounds of Maasai pastoralists in northern Tanzania. We analyse the effect of different grazing pressure on herbaceous vegetation growth and composition, soil properties and water content. I use both observational and experimental studies in the field.

Intended date of graduation: Year 2024, at the University of Hohenheim, Stuttgart, Germany

Funding: Hans Boeckler Stiftung, Germany;

Related publications:

Baumgartner SA, Treydte AC. 2022. Back to the Roots-Do Traditional Maasai Management Strategies Work towards Resilience against Unpredictable Rainfall and Grazing Pressure in Northern Tanzania? IGC Proceedings (1993-2023). 4. https://uknowledge.uky.edu/igc/24/1-2/4

Baumgartner S, Treydte AC, Grant CC, van Rooyen J (2015) Can diverse herbivore communities increase landscape heterogeneity? Comparing wild and domestic herbivore assemblages in a South African savanna. Perspectives in Plant Ecology, Evolution and Systematics 17: 34-43. https://doi.org/10.1016/j.ppees.2014.11.002

Treydte AC, Baumgartner S, Heitkönig IMA, Grant CC, Getz WM (2013) Herbaceous forage and selection patterns by ungulates across varying herbivore assemblages in a South African savanna. PLoS ONE 8(12): e82831. doi:10.1371/journal.pone.0082831.

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Rangeland restoration: Restoration tools to restore soils and plants of degraded rangelands

Members: Annrose Mwangi, co-supervised together with SLU (https://www.slu.se/en/ew-cv/annrose-mwangi/); Aida Bargués Tobella, co-supervisor (https://www.slu.se/en/ew-cv/aida-bargues-tobella/)

This project is part of a FORMAS funded project to improve understanding of the plant-soil-water nexus.We investigate rangeland restoration activities to enhance diversity, adaptation and mitigation of climate change through the pastoralism communities, and improve food and water security in the rangelands of East Africa. We investigate responses of soil-water and plant communities towards different restoration technologies from an interdisciplinary and participatory approach.

Intended date of graduation: Year 2028, at SLU, Umea, Sweden

Funding: FORMAS special call on biodiversity, climate and water (Restore4More: Scaling rangeland restoration in drylands through synergies in the biodiversity-water-climate nexus 2023 – 2027)

Related publications: Not yet

Link: https://www.slu.se/en/collaboration/international/slu-global/triple-l/projects/restore4more/

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Rangeland restoration: Seedbombs as active restoration technology for eastern African rangelands

Members: Gladys Lendii, PhD student (https://www.researchgate.net/profile/Gladys-Lendii-2); Francis Moyo, co-supervisor (https://nm-aist.ac.tz/teams/dr-francis-moyo/); Issakwisa Ngondya, co-supervisor (https://nm-aist.ac.tz/index.php/issakwisa)

In this project, we are testing the seedball technique in the restoration of degraded rangelands and improvement of pastoralist grazing land in Northern Tanzania. We want to understand the pastoralists’ awareness, willingness and preferred grass species for rangeland restoration. We assess the distribution and abundance of preferred native grass species across different livestock grazing zones in rangelands of northern Tanzania and under varying environmental conditions. Then we test the germination rate of the preferred grass species in seedbombs under different environmental conditions.

Intended date of graduation: Year 2025, at NM-AIST, Tanzania

Funding: Rufford Small Grants, College of African Wildlife Management Mweka

Related publications: Not yet

Link: -

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INVASIVE PLANTS

 

Invasive Plant Species Management: The current distribution of Helichrysum species and their effect on orchid species in Kitulo National Park, Tanzania

Members: Christopher Mgimba, PhD student (https://www.researchgate.net/profile/Christopher-Mgimba); Issakwisa Ngondya, co-supervisor (https://nm-aist.ac.tz/index.php/issakwisa); Stuart Smith, collaborator (https://www.hutton.ac.uk/people/stuart-smith/)

Kitulo National Park (KNP) hosts a high diversity of charismatic orchid species. However, KNP has undergone ecological changes in terms of vegetation cover, following the cessation of livestock grazing and crop cultivation. Most of the orchid species are sensitive to ecological changes such as expansion of herbaceous vegetation but so far little is known about the response of orchid species in KNP to the herbaceous native invader plant, Helichrysum species, that have started to dominate some parts of the park. Such information is crucial for successful in-situ conservation of orchids. We assess plant species communities in the field, conducting interviews to understand historical use of this area and doing greenhouse experiments on Helichrysum species germination potential under different environmental conditions.

Intended year of graduation: Year 2024, at the Nelson Mandela African Institution of Science and Technology (NM-AIST), Arusha, Tanzania

Funding: Mbeya University of Science and Technology, Tanzania

Related publications:

Mgimba CA, Smith SW, Ngondya IB, Treydte AC. (2024) The interplay between historical land‐use and the distribution of Helichrysum shrubs in an African‐protected grassland. African Journal of Ecology 62. (2):e13273. https://doi.org/10.1111/aje.13273

 

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PhD Students

Supervision (as a main supervisor):

PhD Theses:

2021 – present    R. Kraus: Understanding spatial and temporal patterns of human-wildlife conflict incidences and identifying mitigation tools for protected area surroundings in Europe and Africa (SU)

2020 – present    C. Mgimba: The distribution of native and invasive herbaceous species in Kitulo National Park, Tanzania (NM-AIST)

2019 – 2024       D. Ladislaus: Impact of human activities on the lesser flamingo (Phoeniconaias minor) population in the Momella Lakes Ecosystem, Tanzania (NM-AIST)

2019 – 2022       L. Theodori: Modeling the Impacts of land use /land cover change on Ecosystem services at Wami-Mbiki-Saadani Ecosystem, Tanzania (NM-AIST, Aridlands)

2018 – present    S. Baumgartner: Water and nutrient availability of semi-arid rangelands under high grazing pressure and rainfall variability (UHOH, NM-AIST)

2017 – present    L. Michler: Adapting to change – co-management scenarios of local pastoralists and protected area management to maintain biological and cultural diversity in the Dzungarian Gobi in Mongolia (UHOH, University of Vienna, Thakin Tal, Mongolia )

2018 – 2022       P. Shayo: The contribution of oysternuts (Telfairia pedata)  to biodiversity conservation and improved community livelihoods in northern Tanzania (NM-AIST, Sokoine University of Agriculture)

2018 – 2021       E. Mohammed: Effects of overgrazing and illegal harvesting on the regeneration and ecology of Balanites aegyptiaca and Ziziphus spina-christi in Dinder Biosphere Reserve, Sudan (NM-AIST, Gezira University)

2018 – 2021       F. Thomas: The role of rangeland pollinators for pastoralist livelihoods in northern Tanzania (NM-AIST, Ministry of Agriculture)

2017 – 2021       C. Leweri: Pastoralism and wildlife conservation in the face of climate change: will shifts in movement patterns and herding strategies resolve conflicts? (NM-AIST, NCAA)

2017 – 2021       S. Abihudi: Phylogenetic relationships, occurrence and sustainable harvesting of Aloe spp. in Tanzania (NM-AIST, University of Uppsala)

2017 – 2020       B. Mwendwa: Potential spread and management options of the invasive tree species Maesopsis eminii in Amani Nature Forest Reserve, Tanzania (NM-AIST, Ministry of Forestry)

2017 – 2020       F. Ojija: Invasive species impact on insect functional groups – the case study of Parthenium hysterophorus in Tanzania (NM-AIST, Greenwich University)

2016 – 2020       G. Mayengo: Understanding the importance of termite mounds and other nutrient hotspots for ungulates in the Issa Valley, Tanzania (NM-AIST, University of Liverpool)

2014 – 2017       N. Emmanuel: Drivers of human-elephant conflicts and their management implications: a case of Rombo area, Kilimanjaro, Tanzania (NM-AIST)

2014 – 2017       I. Ngondya: Invasive species management for sustainable ecosystem conservation in the Ngorongoro Ecosystem, Tanzania (NM-AIST)

2012 – 2017       S. Kawo: Estimating sustainable rangeland productivity under different herbivore pressure and climate change scenarios (UHOH)

2012 – 2017       F. Harich: Conflicts of human land-use, conservation areas, and expanding rubber plantations: The case of Asian elephants in Xishuangbanna (UHOH, Beijing Normal University)

2010 – 2014       H.M. Yusuf: Rangeland management and Carbon stocks in Southern Ethiopia with respect to land use changes and shifting climatic conditions (UHOH)

 

 

Research projects

Publications

A selection from Stockholm University publication database

  • Characterization of bird, reptile, and insect community diversity in constructed wetlands and waste stabilization ponds across Tanzania

    2023. Gerubin Liberath Msaki (et al.). Ecological Engineering 196

    Article

    Wastewater treatment systems, such as Constructed Wetlands (CWs) and Waste Stabilization Ponds (WSPs), have untapped biodiversity enhancement and development potential. Birds, insects, and reptiles, which are displaced by human development, might find refuge in these ecosystems. However, the lack of a detailed characterization of the biodiversity status of these wastewater treatment systems hinders their widespread adoption. Point counts, direct observations, and camera traps were used to assess bird diversity across five CWs and three WSPs in Tanzania in 2021. For insects and reptiles, pitfall and pan traps were laid along established transects, in addition, direct observations and fishnets were also used to assess the reptiles dwelling within the WSPs. Abundance, Shannon index, Simpson index, Margalef index, and evenness index were the diversity parameters used to analyze the diversity of birds, insects, and reptiles. Our results show that among the studied groups and between WSPs and CWs, birds had high species abundance (n = 1132), richness, Margalef index (D = 4.266), evenness (E = 0.815), Shannon diversity (H = 2.881) and Simpson index (λ =0.903). The abundance and diversity of studied groups differed significantly (P < 0.05) between WSPs and CWs. Our study also recorded four reptile species belonging to three orders. Molecular analyses confirmed that insect species belong to nine orders and 13 families, with the order Diptera dominating both CWs and WSPs, followed by Orthoptera, Hymenoptera, and Araneae. We conclude that CW and WSP wastewater treatment systems are important for hosting various populations of birds, reptiles, and insect species.

    Read more about Characterization of bird, reptile, and insect community diversity in constructed wetlands and waste stabilization ponds across Tanzania
  • Environmental factors and non-chemical methods to suppress growth of the invasive plant Gutenbergia cordifolia

    2023. Sarah A. Mero, Issakwisa B. Ngondya, Anna C. Treydte. Acta Oecologica 119

    Article

    Little is known about preferred environmental conditions and non-chemical control of invasive Gutenbergia cordifolia. We assessed the effects of different A. annua crude extract concentrations, synthetic herbicide (glyphosate), fire regime and shade to G. cordifolia germination, shoot and root dry biomass, seedling height and leaf chlorophyll. High concentrations (75%) of A. annua crude extracts significantly reduced germination percentage of G. cordifolia by 25% (F2,4=77.2, p < 0.001), and suppressed shoot and root dry biomass (F2,4 = 80.3, p < 0.001; F2,4=46.104, p < 0.001, respectively) as well as seedling height and leaf chlorophyll (F2,4 = 12.02, p < 0.002; F2,4 = 15.9, p < 0.001), respectively. Medium temperature (60 °C) and long exposure time (5 min) significantly increased G. cordifolia germination percentage (F2,7 = 32.6, p < 0.001) while extreme temperatures (≥150 °C) at both (1 min) short and (5 min) long exposure time completely suppressed germination of G. cordifolia. Under high shade, while germination percentage was a third that of other treatments (F 2, 4 = 20.9, p = 0.008), mean germination took twice as long (F2, 4 = 17.9, p = 0.010) and shoot fresh biomass was reduced by half (F 2, 4 = 16.92, p = 0.004). Shoot and root dry biomass were reduced to more than a third under high shade, seedling height reduced to half but leaf chlorophyll content was not affected (F 2,4 = 6.3, p = 0.030; F 2,4 = 9.1, p = 0.020; F 2,4 = 18.3, p = 0.003; F 2,4 = 3.02, p = 0.120, respectively). We suggest using A. annua as a potential bio-herbicide and highlight considering fire and shade as suppressor tools to control G. cordifolia, but first include in-situ trials to assess their impacts to both native plants and animals.

    Read more about Environmental factors and non-chemical methods to suppress growth of the invasive plant Gutenbergia cordifolia
  • Exploring the future of Kafue National Park, Zambia: Scenario-based land use and land cover modelling to understand drivers and impacts of deforestation

    2023. Julia Dietz, Anna Christina Treydte, Melvin Lippe. Land use policy 126

    Article

    Land use and land cover (LULC) dynamics in tropical forests of sub-Saharan Africa are often difficult to quantify and predict, despite rapid forest losses and increasing human population pressure. As deforestation threatens the biodiversity of both flora and fauna, we used LULC change assessment and scenario modelling to analyse whether policy measures can safeguard the multi-functionality of tropical dry forests in western Zambia from 2010 to 2040. Our data comprised information on deforestation and human encroachment due to i.e., agricultural expansion, charcoal production, infrastructure development in the Kafue National Park (NP) and adjacent Game Management Areas (GMAs) (total area: 7,102,147 ha), which is part of the first Reducing Emissions from Deforestation and Forest Degradation (REDD+) focus areas in Zambia. We modelled a business-as-usual scenario (BAU) and four REDD+ policy-screening scenarios with varying levels of protection enforcement and future annual deforestation rates. We quantified scenario impacts on forest cover using three indicators: cropland and forest-related LULC trajectory, forest connectivity, and long-term carbon stock changes in 2040. Scenario results suggested that only under strong enforcement and low demand for agricultural areas, deforestation in Kafue NP and GMAs could be avoided by 93% (40,457 ha) and 1% in carbon stocks could be gained by 2040 in comparison to BAU. Spatial analyses revealed that cropland expansion will continue to encroach protected areas. We highlight that variations in carbon stocks and forest fragmentation were small across scenarios which has implications for land use management and the expected future benefits of REDD+ projects. The combination of GIS, scenario development and LULC modelling helped to identify and locate potential future deforestation and LULC changes. This can support appropriate management pathways of REDD+ induced local and national leakage effects and related decision making.

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  • Insect visitation and pollination networks across traditional rangeland management categories in a Northern Tanzanian rangeland

    2023. Faith T. Mpondo (et al.). Global Ecology and Conservation 46

    Article

    The structure of pollination networks is critical to ecosystem stability and functioning. We investigated pollinator-plant interactions to understand the foraging preference and develop pollination networks in a semi-arid rangeland of different grazing management categories in Tanzania. Along three line transects, each measuring 100 m, in each of the four grazing management categories (private and communal enclosures, wet and dry season grazing areas), we laid out three quadrats measuring 5 m x 5 m (25 m2,) located 30 m apart. We recorded insects visiting flowering plants for two consecutive days in each quadrat every week at each site from April to May, in 2019 and 2020. Aspilia mossambicensis received the most significant proportion of insect visitors (28%), followed by Justicia debile (21%). The mean protein concentration in sampled pollen varied significantly between plant species (& chi;2 = 25.9, P = 0.001), with Solanum incanum containing the highest concentration (299.3 & PLUSMN; 0.68) g/100 g. We did not notice any correlation between honey bee visitation and protein concentration in pollen (r = -0.471, P = 0.239) nor with fatty acids concentration (r = 0.253, P = 0.546). When comparing pollinator-plant network properties including connectance, nestedness, robustness, number of links, modularity, network diversity and linkage density across rangeland management, we found that the private enclosure contained significantly larger networks than the communal enclosure, the dry and the wet season grazing sites. We conclude that particularly private enclosures are vital to promote pollination networks in our studied rangeland system as they include important pollinator forage plants.

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  • To move or not to move—factors influencing small-scale herder and livestock movements in the Dzungarian Gobi, Mongolia

    2023. Lena M. Michler (et al.). Regional Environmental Change 23 (4)

    Article

    In Mongolia, where nomadic pastoralism is still practiced by around one-third of the population, increasing livestock numbers, socio-economic constraints and climate change raise concerns over rangeland health. Little empirical evidence explains what triggers camp moves of pastoralists in the Dzungarian Gobi in Mongolia, which factors influence grazing mobility around camps, and how altitudinal migration benefits small livestock. We combined GPS tracking data of 19 small livestock herds monitored from September 2018 to April 2020 with remotely sensed climate and environmental data. We used general linear-mixed models to analyse variables influencing camp use duration and daily mobility patterns. To understand the importance of the altitudinal migration, we compared climatic conditions along the elevation gradient and looked at seasonal body weight changes of small livestock. We found that available plant biomass and season best explained camp use duration. Daily walking distance and maximum distance from camp increased with camp use duration. Pasture time increased with increasing biomass and rising temperatures. We conclude that herders in the Dzungarian Gobi have optimized pasture use by reacting to changes in biomass availability at landscape and local scale, and by embracing altitudinal migration. Flexibility in grazing mobility seems to have enabled local herder communities to practise sustainable pasture use. Maintaining this mobility will most likely be the best strategy to deal with environmental change under the current climate change scenarios.

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  • A Socio-Ecological Approach to Understanding How Land Use Challenges Human-Elephant Coexistence in Northern Tanzania

    2022. John Erasto Sanare (et al.). Diversity 14 (7)

    Article

    A globally rapid land use/land cover change (LULC) in human-transformed landscapes alters the interface of human-wildlife interactions due to shifting socio-ecological and environmental pressures. Understanding these shifts is crucial for mitigating repeated negative interactions that escalate conflict states between people and wildlife. This study aimed to understand LULC changes over 30 years (1989-2019), with more recent spatio-temporal patterns of high pressure at the human-elephant interface, and potentially underlying environmental and human-driven factors that affect elephant movement patterns. We analyzed a dataset of 923 human-elephant conflict occurrences, mainly crop foraging incidents, in the Enduimet Wildlife Management Area (EWMA) between the years 2016 and 2020 and combined these data with LULC for year 2019 to understand potential drivers of conflict and assess how agricultural land and settlement have increased over time. We further used GPS datasets of elephants collared between 2019 to 2020 to understand elephant movement patterns in changing land use types. Landsat image analysis revealed that 41% of the area had been converted into farmlands and settlements within the last three decades, which creates elephant-intolerant habitats and the potential to increase pressure at the human-elephant interface. Collared elephants using EWMA moved through all land use types and did not avoid settlements, although they moved through these at higher speeds, reflecting perception of risk. Elephants travelled slightly more slowly in farmland, likely reflecting the availability of foraging opportunities. Our analysis shows that human-induced LULC changes and the encroachment into elephant habitats have resulted in spatially and temporally predictable increases in HEC in EWMA, driven by the proximity of farmlands and protected areas (PAs), so that incompatible land uses are the principal drivers of damage to human livelihoods and increased risks to Tanzanian (and Kenyan) natural capital. Communities in Enduimet urgently need support to increase the effective distance between their farming activities and the PAs. Village-level crop protection and small-scale land-use planning around PAs are important first steps to halt an escalating conflict situation but need to be supported with longer-range strategies that separate incompatible land-use types and encourage the cultivation of alternative crops and livelihood diversification.

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  • Forage selection by Masai giraffes (Giraffa camelopardalis tippelskirchi) at multiple spatial scales

    2022. Matana Levi (et al.). Journal of Mammalogy 103 (3), 737-744

    Article

    Management of rangelands requires knowledge of forage species that are preferred or avoided by wildlife and livestock. A recent expansion of woody vegetation into previously open grasslands in African savanna ecosystems negatively impacts many mammalian grazers. Nevertheless, the ecological role of bush encroacher plant species as food may present a benefit for browsing species. We quantified diet selection by Masai giraffes (Giraffa camelopardalis tippelskirchi) through foraging observations and vegetation sampling in the Tarangire Ecosystem of Tanzania, which includes large areas of a native shrub that livestock managers have classified as an encroacher species (Dichrostachys cinerea). We compared woody plant species used by giraffes for foraging with availability at two different spatial scales during the wet and dry seasons. Giraffes selected some woody plants such as Vachellia species while significantly avoiding others, both at the local and landscape scales. Giraffes preferred foraging on D. cinerea at both spatial scales and in both the wet and dry seasons. Management that has focused on benefiting grazing livestock by removal of encroaching species (e.g., D. cinerea) may have unintended consequences for wildlife, especially for browsing species like giraffes that feed extensively on the expanding bush species.

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  • Growth performance of the neglected crop Telfairia pedata across elevation and climate gradients in Northern Tanzania

    2022. Philipina F. Shayo, Ernest R. Mbega, Anna C. Treydte. Trees, Forests and People 7

    Article

    Herbaceous vines, including the neglected crop Telfairia pedata, play a key role in small-holder livelihoods of Eastern Africa. Despite this species’ importance in enhancing agro-biodiversity, little is known about its distribution and growth performance in relation to environmental variables. We collected biophysical and environmental data, i.e., on climate and elevation, for 346 T. pedata vines across four districts of Northern Tanzania from September, 2019, to February, 2020. The four sites included Same, Lushoto, Muheza and Arumeru districts. We found that plants of T. pedata were mainly grown in elevations ranging between 900 to 1800 m above sea level with annual rainfall regimes of 1000 to 1400 mm. We recorded large abundance of T. pedata in Lushoto (46%) and Arumeru (28%) and observed that the number of fruits and fruit diameter were both positively correlated with elevation across the study districts. There was a significant effect of elevation on number of seeds, with Same district having more seeds across the studied districts. Rainfall had a significant effect on fruit diameter and number of seeds in the study districts. Furthermore, the tree species Albizia schimperiana was most commonly (in 40% of the cases) associated with T. pedata, followed by Persea americana (14%), and Croton macrostachyus (9%). We highlight that mountainous regions are ideal for this highly nutritious crop, and that native trees are of high importance for enriching this vine to current agro-ecosystems. Our findings will increase awareness on the importance of raising T. pedata crop, livelihood diversification, and increasing biodiversity through production of this orphan crop in small-holder farms.

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  • Land Use Land/Cover Change Reduces Woody Plant Diversity and Carbon Stocks in a Lowland Coastal Forest Ecosystem, Tanzania

    2022. Lucas Theodori Ntukey, Linus Kasian Munishi, Anna Christina Treydte. Sustainability 14 (14)

    Article

    The East-African lowland coastal forest (LCF) is one of Africa's centres of species endemism, representing an important biodiversity hotspot. However, deforestation and forest degradation due to the high demand for fuelwood has reduced forest cover and diversity, with unknown consequences for associated terrestrial carbon stocks in this LCF system. Our study assessed spatio-temporal land use and land cover changes (LULC) in 1998, 2008, 2018 in the LCF ecosystem, Tanzania. In addition, we conducted a forest inventory survey and calculated associated carbon storage for this LCF ecosystem. Using methods of land use change evaluation plug-in in QGIS based on historical land use data, we modelled carbon stock trends post-2018 in associated LULC for the future 30 years. We found that agriculture and grassland combined increased substantially by 21.5% between the year 1998 and 2018 while forest cover declined by 29%. Furthermore, forest above-ground live biomass carbon (AGC) was 2.4 times higher in forest than in the bushland, 5.8 times in the agriculture with scattered settlement and 14.8 times higher than in the grassland. The estimated average soil organic carbon (SOC) was 76.03 +/- 6.26 t/ha across the entire study area. Our study helps to identify land use impacts on ecosystem services, supporting decision-makers in future land-use planning.

    Read more about Land Use Land/Cover Change Reduces Woody Plant Diversity and Carbon Stocks in a Lowland Coastal Forest Ecosystem, Tanzania
  • Land Use/Cover Change Reduces Elephant Habitat Suitability in the Wami Mbiki-Saadani Wildlife Corridor, Tanzania

    2022. Lucas Theodori Ntukey (et al.). Land 11 (2)

    Article

    Wildlife corridors are critical for maintaining the viability of isolated wildlife populations and conserving ecosystem functionality. Anthropogenic pressure has negatively impacted wildlife habitats, particularly in corridors between protected areas, but few studies have yet quantitatively assessed habitat changes and corresponding wildlife presence. We quantified land use/land cover and human–elephant conflict trends over the past two decades in the Wami Mbiki–Saadani (WMS) wildlife corridor, Tanzania, using RS and GIS combined with human–wildlife conflict reports. We designed landscape metrics and habitat suitability models for the African savanna elephant (Loxodonta africana) as a large mammal key species in the WMS ecosystem. Our results showed that forest cover, a highly suitable habitat for elephants, decreased by 3.0% between 1998 and 2008 and 20.3% between 2008 and 2018. Overall, the highly suitable habitat for elephants decreased by 22.4% from 1998 to 2018, when it was scarcely available and when small fragmented patches dominated the unprotected parts of the corridor. Our findings revealed that large mammalian habitat conservation requires approaches beyond habitat-loss detection and must consider other facets of landscape patterns. We suggest strengthening elephant habitat conservation through community conservation awareness, wildlife corridor mapping, and restoration practices to ensure a sustainable pathway to human–wildlife coexistence. 

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  • Livestock Browsing Threatens the Survival of Balanites aegyptiaca Seedlings and Saplings in Dinder Biosphere Reserve, Sudan

    2022. Elmugheira M. I. Mohammed (et al.). Journal of Sustainable Forestry 41 (10), 1046-1063

    Article

    While the impact of livestock grazing has been frequently assessed for grasses, little is known about how livestock affects tree seedlings and saplings. We explored the effects of goat, cattle and camel browsing on the survival of Balanites aegyptiaca seedlings and saplings, a broadleaved evergreen tree species indigenous to Sudan, in Dinder Biosphere Reserve-Sudan (DBR). We used a stratified sampling design with four sites: GOA (mainly browsed by goats), CAT and CAM being mainly browsed by cattle and camels, respectively, while CON was a control area without any livestock browsing. We tested the survival, mortality and recovery of seedlings and saplings across different sites. Our results revealed that mortalities of seedlings in GOA were almost four times higher than that of CAM and CON and twice that of CAT (F3,196 = 100.39, P < .001). Further, sapling mortality was three times higher in GOA than that observed in CAT and CON (F3,196 = 73.4, P < .001). We found that seedlings recover better than saplings, and, unexpectedly, goat browsing severely affected the natural regeneration of B. aegyptiaca in DBR compared to other livestock species. Our study findings contribute to sustainable forest management and show that particularly goat browsing needs to be suppressed for conservation of vulnerable tree species. 

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  • Moving Toward the Greener Side: Environmental Aspects Guiding Pastoral Mobility and Impacting Vegetation in the Dzungarian Gobi, Mongolia

    2022. Lena M. Michler (et al.). Rangeland Ecology & Management 83, 149-160

    Article

    Livestock grazing often intensifies around herder camps, which can lead to degradation, particularly in arid areas, where vegetation is scarce. In Mongolia, nomadic herders have covered long distances between camps and changed camps regularly for centuries. However, changing socioeconomics, rising livestock numbers, and climatic change have led to growing concerns over rangeland health. To understand travel mobility and livestock grazing patterns, we combined Global Positioning System tracking data of goats, remotely sensing pasture productivity, and ground-based vegetation characteristics in the Great Gobi B Strictly Protected Area, Mongolia. We assessed herder preferences for camp selection, followed 19 livestock herds over 20 months, determined use and nutrient contents of the most dominant plant communities, and estimated plant species richness, vegetation cover, and biomass within different grazing radii around camps. Biomass availability was key for herder decisions to move camps, but in winter, other factors like shelter from wind were more important. Camps were mainly located in Stipa spp. communities, agreeing with herder preferences for this highly nutritious species, and its dominance around camps. Herders changed their camp locations on average 9 times yearly, with a maximum distance of 70–123 km between summer and winter camps, and an average visitation period of 25–49 d per camp, depending on season. Small livestock spent > 13−17 h daily within a radius of 100 m from camp, and livestock use intensity decreased steeply with distance from camp but was remarkably similar around spring, autumn, and winter camps on the Gobi plains. However, we found little evidence for a corresponding gradient in plant species richness, biomass, and cover on the Gobi plains. The high mobility of local herders and the overriding impact of precipitation on pasture dynamics contribute to a sustainable vegetation offtake by livestock in the nonequilibrium rangelands of the Dzungarian Gobi.

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  • Qualitative Modeling for Bridging Expert-Knowledge and Social-Ecological Dynamics of an East African Savanna

    2022. Maximilien Cosme (et al.). Land 11 (1)

    Article

    Sub-Saharan social-ecological systems are undergoing changes in environmental conditions, including modifications in rainfall pattern and biodiversity loss. Consequences of such changes depend on complex causal chains which call for integrated management strategies whose efficiency could benefit from ecosystem dynamic modeling. However, ecosystem models often require lots of quantitative information for estimating parameters, which is often unavailable. Alternatively, qualitative modeling frameworks have proved useful for explaining ecosystem responses to perturbations, while only requiring qualitative information about social-ecological interactions and events and providing more general predictions due to their validity for wide ranges of parameter values. In this paper, we propose the Ecological Discrete-Event Network (EDEN), an innovative qualitative dynamic modeling framework based on if-then rules generating non-deterministic dynamics. Based on expert knowledge, observations, and literature, we use EDEN to assess the effect of permanent changes in surface water and herbivores diversity on vegetation and socio-economic transitions in an East African savanna. Results show that water availability drives changes in vegetation and socio-economic transitions, while herbivore functional groups have highly contrasted effects depending on the group. This first use of EDEN in a savanna context is promising for bridging expert knowledge and ecosystem modeling.

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  • Retaliatory killing negatively affects African lion (Panthera leo) male coalitions in the Tarangire-Manyara Ecosystem, Tanzania

    2022. Nancy Felix (et al.). PLOS ONE 17 (8)

    Article

    In landscapes where people and lions coexist, conflicts are common due to livestock predation and threats to human safety. Retaliatory lion killing by humans is often a consequence and is one of the leading causes of lion population declines across Africa. We assessed the effects of retaliatory lion killing on male lion coalitions in the Tarangire-Manyara Ecosystem (TME) using a long-term dataset of lion monitoring for ten lion prides, spanning over a fourteen year-period from 2004-2018. We also interviewed 214 respondents about their attitudes and awareness of the effects of retaliatory killing on lions. We found that male lion coalitions were larger and lasted for a longer tenure period in locations with low risk of retaliatory killing, as well as far away from active hunting blocks. Further, young people (18-35 years old) had a more positive attitude towards lion existence and conservation compared to older age classes. Surprisingly, people with primary or secondary level of education were more likely to having lions killed if they attack livestock compared to people with no formal education, although the former supported lion presence for tourism in protected areas. We conclude that retaliatory killing has a large effect on long-term lion coalition dynamics and, thus, survival. Community awareness on retaliation effect varies widely, and we recommend implementing better education and policy strategies at TME to protect the declining carnivore populations. 

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  • Social knowledge, attitudes, and perceptions on wastewater treatment, technologies, and reuse in Tanzania

    2022. Gerubin Liberath Msaki (et al.). Water Reuse 12 (2), 223-241

    Article

    This study assessed the social knowledge, attitude, and perceptions (KAPs) on wastewater treatment, the technologies involved, and its reuse across different wastewater treatment areas in four regions of Tanzania. We used both quantitative and qualitative data collection methods in a household-level questionnaire (n=327) with structured and semi-structured questions, which involved face-to-face interviews and observation. Our results show that social KAPs surrounding wastewater treatment and reuse were sufficient based on KAP scores achieved from asked questions. However, the general knowledge on treatment technologies, processes, and reuse risks was still low. Of the respondents, over 50% approved using treated wastewater in various applications, while the majority (93%) were reluctant if the application involved direct contact with the water. Furthermore, over 90% of interviewees did not know the technologies used to treat wastewater and the potential health risks associated with its use (59%). Multivariate analysis of variance revealed significant differences (P<0.05) in the KAPs on treated wastewater across different studied demographic variables, i.e., age, sex, and education level. Therefore, we recommend that more effort be spent on providing public education about the potential of wastewater treatment and existing technologies in order to facilitate their adoption for the community's and environment's benefit.

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  • Spatial and seasonal group size variation of wild mammalian herbivores in multiple use landscapes of the Ngorongoro Conservation Area, Tanzania

    2022. Cecilia M. Leweri (et al.). PLOS ONE 17 (4)

    Article

    Group sizes of wild herbivores can be indicators of ecosystem health and proxies for individual and population fitness, particularly in areas where human activities have become increasingly common. We recorded 176 single- and multi-species groups of wild herbivores in human-dominated landscapes of the Ngorongoro Conservation Area (NCA) during dry and wet seasons. We analyzed how wild herbivore group sizes were affected by: (1) season, (2) distance to fully protected area (NCA crater) and to streams, (3) distance to human settlements, and (4) numbers of livestock. Group sizes were generally larger during the wet season than during the dry season and varied seasonally with distance to NCA crater, streams, and human settlements. During the wet season, larger groups were observed further away from the NCA crater whereas the opposite pattern was apparent during the dry season. Average wild herbivore group sizes increased by about three-fold with increasing distance from the streams during the dry season but were invariant to streams during the wet season. Furthermore, during the dry season, group sizes were larger close to settlements but varied little with distance to settlements during the wet season. While livestock presence did not directly affect wild herbivore group size, distance to settlements, streams and distance to the Ngorongoro crater in interaction with rainfall seasonality did. We conclude that the NCA crater functions as a key resource area for wild herbivores such as wildebeest (Connochaetes taurinus) and zebra (Equus quagga burchelli) during the dry season, highlighting the need for its full protection status in this Man and Biosphere reserve.

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  • Spatio-Temporal Water Quality Determines Algal Bloom Occurrence and Possibly Lesser Flamingo (Phoeniconaias minor) Presence in Momella Lakes, Tanzania

    2022. Deogratias Ladislaus Lihepanyama, Patrick Alois Ndakidemi, Anna Christina Treydte. Water 14 (21)

    Article

    Eutrophication and algal blooms have sparked worldwide concern because of their widespread effects on water-dependent species. Harmful algal blooms can cause fatal effects to lesser flamingos (Phoeniconaias minor), obligatory filter feeders and vital bio-indicators in soda lakes. Thus, early detection of algal blooms and potential indicators in water quality is critical, but general tools are lacking in eastern African soda lakes. We monitored algal biomass changes and related water physico–chemical variables for 12 consecutive months in the lakes Big Momella and Rishateni in northern Tanzania. We used chlorophyll-a to measure algal biomass and quantified water physico–chemical variables that might influence algae growth. We also monitored lesser flamingo numbers to understand trends across the year and according to algal bloom occurrence. Algal biomass was strongly related to water nitrogen (r = 0.867; p < 0.001) and phosphorus (r = 0.832; p < 0.001). Monthly patterns showed significant differences in water quality and algal biomass (F = 277, p < 0.001) but not across sampling sites (F = 0.029, p = 0.971). Lesser flamingo numbers seemed to be related to algal biomass at Lake Big Momella (r = 0.828; p < 0.001) and shortly after algal biomass peaked high (i.e., March and April 2021), flamingo numbers declined. Lake Rishateni showed similar patterns. Our findings can provide a basis towards understanding the factors contributing to temporal changes in lesser flamingo abundance due to spatio–temporal water quality variations, which is important for optimising conservation efforts for the species in these unique Momella lakes.

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  • The stocking density and regeneration status of Balanites aegyptiaca in Dinder Biosphere Reserve, Sudan

    2022. Elmugheira M. I. Mohammed (et al.). Trees, Forests and People 8

    Article

    Balanites aegyptiaca as food, feed, and medicinal tree species, contributes significantly to the livelihoods and food security of forest-based communities, particularly in the Sahel. However, up-to-date information on the stocking density and regeneration status of the species is lacking. The current study bridged this gap and explored the species status in Dinder Biosphere Reserve, Sudan, across 150 sample plots of 40×25 m2 randomly distributed in the stratified sites of the reserve. After checking for normality using Shapiro Wilk test, a two-way ANOVA with Tukey's post hoc test (α = 0.05) in JAMOVI (Version 1.1.7) has been used to compare the tree density, basal area, and volume between the assessed sites and within the sites. The study found that the stocking density of B. aegyptiaca seedlings, saplings, and adult trees in the non-disturbed sites were double and three times equal to that of the highly disturbed sites and significantly differed between sites (F2,147 = 122.4 and P < 0.001; F2,147 = 148.3 and P = 0.001; F2,147 = 131.2 and P = 0.021, respectively). Moreover, the smallest tree crown diameter, basal area, and volume were observed in the highly disturbed sites. The study concluded that unbalanced utilization of B. aegyptiaca in the biosphere severely reduced the species population and disturbed their dynamics, which might also affect the food security in the area. Therefore, an introduction of monitoring and awareness-raising programs is urgently needed to maintain this valuable tree species and manage it sustainably.

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  • Using Trophy Hunting to Save Wildlife Foraging Resources: A Case Study from Moyowosi-Kigosi Game Reserves, Tanzania

    2022. Nyangabo V. Musika (et al.). Sustainability 14 (3)

    Article

    Globally, the role of trophy hunting in wildlife conservation has been a topic of much debate. While various studies have focused on the financial contribution of trophy hunting towards wildlife conservation, little is known about whether hunting activities can protect wildlife forage resources. We examined the effect of illegal livestock grazing on wildlife habitat in operational and non-operational wildlife hunting blocks in Moyowosi-Kigosi Game Reserves (MKGR), Tanzania. We assessed whether the physical presence of hunting activities lowered illegal grazing and, thus, led to higher vegetation quality. We compared 324 samples of above-ground biomass (AGB) and grass cover between control (0.0007 cattle ha−1), moderately (0.02 cattle ha−1), and intensively (0.05 to 0.1 cattle ha−1) grazed hunting blocks. Likewise, we assessed soil infiltration, soil penetration, soil organic carbon (SOC), and soil Nitrogen, Phosphorus, and Potassium (N-P-K) across grazing intensity. Illegal grazing decreased AGB by 55%, grass cover by 36%, soil penetration by 46%, and infiltration rate by 63% compared to the control blocks. Illegal grazing further lowered SOC by 28% (F2,33 = 8, p < 0.002) but increased soil N by 50% (F2,33 = 32.2, p < 0.001) and soil K by 56% (H (2) = 23.9, p < 0.001), while soil P remained stable. We further examined if Hunting Company (HC) complements anti-poaching efforts in the Game Reserves (GR). We found that HC contributes an average of 347 worker-days−1 for patrol efforts, which is 49% more than the patrol efforts conducted by the GR. However, patrol success is higher for GR than HC (F1,21 = 116, p < 0.001), due to constant surveillance by HC, illegal herders avoided invading their hunting blocks. We conclude that illegal grazing severely reduced vegetation and soil quality in MKGR. We further claim that trophy hunting contributes directly to wildlife habitat preservation by deploying constant surveillance and preventing illegal grazing. We propose maintaining trophy hunting as an essential ecological tool in wildlife conservation.

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  • Balancing Bees and Livestock: Pastoralist Knowledge, Perceptions and Implications for Pollinator Conservation in Rangelands, Northern Tanzania

    2021. Faith Thomas Mpondo, Patrick A. Ndakidemi, Anna C. Treydte. Tropical Conservation Science 14

    Article

    Insect pollinators provide numerous ecosystem services that support other living organisms. While pollinators play a large role in cropping systems, little is known about their presence and function in rangeland ecosystems, which have recently become fragmented and overexploited at an extraordinary rate. We assessed local Maasai knowledge on insect pollinators and how pollinators affect livelihood diversification in Simanjiro rangelands, Tanzania. Through questionnaires, key informant interviews, focus group discussions, and field observations, we found varied insect knowledge among Maasai herders. Lasioglossum of sub genus Ipomalictus and Syriphidae were the least commonly recognized pollinators as only 24%, and 7% of participants could identify them, respectively. Responses varied significantly between men and women (F = 7.397, p = .007). Commiphora africana, Acacia mellifera and Albizia anthelmintica were noted as most important bee forage plants while observations showed Aspilia mossambicensis, Justicia debile and Acacia tortilis. Most (77%) of Maasai herders showed limited ability to link pollinators and rangeland wellbeing. Beekeeping contributed to livelihood diversification for 61% of respondents, with women participating more frequently than men (chi(2) = 46.962, p = .0001). Beekeeping was positively influenced by education level (R = .421, p < .0001) and occupation (R = .194, p = .009). Pollinator declines were attributed to climate change (47%), agriculture (37%), and habitat destruction (8%). We conclude that Maasai have limited knowledge of common pollinator groups and their roles. Community outreach and training should bridge the knowledge gap in pastoralist communities to fully realize pollinator benefits and highlight the importance of rangeland health.

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  • Comparison of the effects of a broad-spectrum herbicide and a bio-herbicide on insect flower visitation in the Serengeti ecosystem, Tanzania

    2021. Mecklina M. Mbundi (et al.). Journal for Nature Conservation 64

    Article

    The functional role of insect visitors on flowering plants is crucial to both natural and agricultural ecosystems. While, few studies have addressed the impact of invasive plant species on insect visitors, even less is known about how management practices against invasive plants may affect plant-pollinator interactions. We assessed how natural versus chemical-based management against the invasive plant Gutenbergia cordifolia affected insect visitors in Mwiba area, Tanzania. We compared the number of insect visitors, diversity and richness, the number of inflorescences visited, inflorescences abundance and flower diversity across treatments of Desmodium uncinatum crude leaves extract (DUL), the chemical glyphosate (GLY), and none /control (CON). We found that more than half (55%) of the insect visitors observed were found visiting flowering plants in DUL plots, followed by CON with 26% and GLY plots with 19%. Further, DUL plots had almost twice as many inflorescences visited compared to CON and GLY plots. Inflorescence's abundance and flower diversity were significantly higher in DUL plots compared to CON and GLY plots. Our study revealed that DUL treatment did not disrupt insect flower visitation but rather attracted more insects. We conclude that using the natural plant extract treatment is highly preferable to the chemical management of invasive plants such as G. cordifolia, as the DUL treatment maintained and even enhanced flower diversity while suppressing G. cordifolia and fostering insect visitors.

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  • Conservation status revision and communities' perceptions of 22 Aloe species in Tanzania

    2021. Siri A. Abihudi, Hugo J. de Boer, Anna C. Treydte. Plant Ecology and Evolution 154 (3), 391-404

    Article

    Background and aims – Many Aloe species are globally threatened due to overharvesting for trade and habitat destruction. CITES regulates their international trade. In Tanzania, 50% of all existing Aloe species had previously been assessed, though some of these assessments were Data Deficient. For those with sufficient data, an update is required as the rate of decline has rapidly increased over the last years.

    Material and methods – We estimated Area of Occupancy (AOO), Extent of Occurrence (EOO), and number of locations for 22 Tanzanian Aloe species using the Geospatial Conservation Assessment software (GeoCAT). We assessed the reasons leading to their decline based on direct field observations and community perceptions.

    Key results – We revised the conservation status of 22 Aloe species; two were assessed as Critically Endangered, ten as Endangered, five as Vulnerable, and five as Least Concern. We re-discovered the Critically Endangered Aloe boscawenii, which had not been seen in Tanzania for more than six decades. We propose to downgrade the endemic Aloe dorotheaeAloe leptosiphon, and Aloe flexilifolia from Critically Endangered to a lower threat level. The community perception on Aloe species availability did not accurately reflect their categorisation based on the IUCN criteria B. We identified agricultural activities and climate change effects as the two main threats to Tanzanian Aloe species.

    Conclusion – We conclude that overall numbers are declining for 22 Aloe species in Tanzania, mainly due to human activities. We recommend the implementation of laws and policies to protect their natural habitats.

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  • Cropping patterns along an altitudinal gradient and their implications to wildlife conservation in Rombo, Tanzania

    2021. Naza E. Mmbaga, Linus K. Munishi, Anna C. Treydte. Global Ecology and Conservation 28

    Article

    Ecosystem and livelihood sustainability of small-scale farmers in Eastern Africa are often challenged by climate change and unsustainable land use practices. Little is known on the small-scale temporal processes of cropping systems in relation to long-term climatic conditions. To understand the climatic influence on the cropping patterns, and its implications to wildlife/elephant conservation, our study used a combination of time-series datasets on crop and climate as well as geo-spatial layers spanning more than three decades. To validate the information analyzed from secondary data, we carried out participatory observation and interviews, whereby about 5% of village households were selected along an altitudinal gradient of Rombo area, Tanzania. We generated land use change maps using Geographical Information System (ArcGIS 10.4) and used Spearman's correlation analysis to assess the influence of rainfall, temperature, and crop yield on the observed longitudinal changes in the crop types and other land use patterns both within and across altitudinal gradients. We found that perennial crops like coffee and banana concentrated in upper agro-ecological zones, with a clear division line above 1230 masl while seasonal crops like maize and beans were mostly cultivated in lowlands (below 1230 masl). The results further showed that coffee yields significantly declined with higher average annual minimum temperatures over the last 16 years. Within the same time period, there was a disproportionate shift from coffee to seasonal crop cultivation such as maize and beans. Elephant numbers declined by about 38%, while human settlement area increased by 28% over the last 30 years. We conclude that changes in land use and shifts in climate and cropping patterns have important implications for elephant conservation and sustainability of the ecosystem in Rombo area, Tanzania.

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  • Illegal harvesting threatens fruit production and seedling recruitment of Balanites aegyptiaca in Dinder Biosphere Reserve, Sudan

    2021. Elmugheira M. Mohammed (et al.). Global Ecology and Conservation 29

    Article

    Illegal harvesting negatively affects the forest tree populations, particularly in sub-Saharan Africa, but little is known how fruit production and seedling recruitment are impacted. We assessed recruitment parameters of Balanites aegyptiaca trees in the Dinder Biosphere Reserve (DBR) across 100 sample plots of 25 m x 40 m in both human-impacted (disturbed) and undisturbed sites. We found that the average number of fruiting branches of B. aegyptiaca in the undisturbed sites were three times as high as those in the disturbed sites (F1,98 = 139, P < 0.001). Further, fruiting branches were positively correlated with crown width (R2 = 0.71, beta = 7.1, P = 0.01) across both sites. The height and crown width of B. aegyptiaca in the undisturbed sites were double that of the disturbed sites (F1,196 = 80, P < 0.001; F1,196 = 94.8, P < 0.001). Saplings and seedlings at the undisturbed sites were three times and twice that of the disturbed sites, respectively (F1,196 = 94.5, P < 0.001; F1,196 = 100.8, P < 0.001), with a positive correlation to the average number of fruiting branches (R2 = 0.74, beta = 0.45, P < 0.001). The soil nitrogen and phosphorus contents beneath trees in the undisturbed sites were almost double that of those in the disturbed sites (F1, 196 = 68.1, P < 0.001; F1, 196 = 97.9, P < 0.001) while sodium and electrical conductivity were by about 50% lower (F1, 196 = 535.8, P < 0.001; F1, 196 = 16.1, P < 0.001). We conclude that illegal harvesting in DBR severely reduced tree structure and recruitment parameters of B. aegyptiaca, which might also have impacted soil fertility. We urge for intensive monitoring and awarenessraising programs to conserve this vulnerable tree species.

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  • Spatio-Temporal Patterns of Increasing Illegal Livestock Grazing over Three Decades at Moyowosi Kigosi Game Reserve, Tanzania

    2021. Nyangabo V. Musika (et al.). Land 10 (12)

    Article

    The global increase of livestock has caused illegal intrusion of livestock into protected areas. Until now, hotspot areas of illegal grazing have rarely been mapped, long-term monitoring data are missing, and little is known about the drivers of illegal grazing. We localized hotspots of illegal grazing and identified factors that influenced spatio-temporal patterns of illegal grazing over three decades in the Moyowosi Kigosi Game Reserve (MKGR), Tanzania. We used questionnaires with local pastoralists (N = 159), georeferenced aerial survey data and ranger reports from 1990–2019 to understand the reasons for illegal grazing in the area. We found that hotspots of illegal grazing occurred initially within 0–20 km of the boundary (H (3) = 137, p < 0.001; (H (3) = 32, p < 0.001) and encroached further into the protected area with time (H (3) = 11.3, p = 0.010); (H (2) = 59.0, p < 0.001). Further, livestock herd sizes decreased with increasing distance from the boundary (R = −0.20, p = 0.020; R = −0.40, p = 0.010). Most interviewees (81%) claimed that they face challenges of reduced foraging land in the wet season, caused by increasing land used for cultivation, which drives them into the MKGR to feed their livestock. We conclude that there is spatio-temporal consistency in the illegal livestock intrusion over three decades, and hotspot areas are located along the boundary of the MKGR. We suggest focusing patrols at these hotspot areas, especially during the wet season, to use limited law enforcement resources effectively.

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  • The Potential of Oyster Nuts (Telfairia pedata) for Environmental Conservation and Food Security in Tanzania: A Review

    2021. Philipina F. Shayo, Ernest R. Mbega, Anna C. Treydte. Human Ecology 49, 495-504

    Article

    The oyster nut, Telfairia pedata, a vine that grows on tall trees, is native only to Tanzania and Uganda. Its nuts are valued by the local population mainly because of their lactogenic properties. Despite its nutritional, economic, and environmental benefits and its low management demands, little is known about why this species has almost disappeared from local markets and farmlands. We selected 187 publications that described the current nutritional, environmental, and commercialization potential of Telfairia species as well as their socioeconomic importance, domestication, and utilization in East Africa. Most studies (60%) mentioned the nutritional and health benefits of Telfairia species, while 40% described their socioeconomic and environmental potentials. Almost half of the studies (47%) cited lack of alternative propagation methods to seeds, including cuttings, tissue culture, and grafting, as a constraint for oyster nut development. We conclude that studies on oyster nut production are rare despite its potential to contribute to food security, environmental conservation, and commercialization. The future of oyster nut production depends on the efforts by agriculturalists, conservationists, and nutritionists to conduct collaborative research and outreach programmes on this underutilized crop to diversify livelihoods of Tanzania's smallholder farmers.

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  • Traditional rangeland management can conserve insect pollinators in a semi-arid rangeland, northern Tanzania

    2021. Faith T. Mpondo (et al.). Acta Oecologica 113

    Article

    Globally, pollinators are threatened by land-use changes, including habitat degradation. East African rangelands are under pressure due to livestock population increase and overutilization, which lead to degradation of vegetation and soils. While traditional grazing management is widely used to restore vegetation, little is known how this affects insect pollinators. We investigated whether differently managed rangeland areas harbor different insect pollinator abundance, richness and diversity in Simanjiro, Tanzania. We established twelve blocks in four grazing areas under different management categories (private and communal enclosures, wet and dry season grazing lands) and used pan traps and sweep nets to collect insect pollinators. We collected a total of 1977 insects, representing 44 families and 239 species. Beetles were most frequently trapped, with 646 (33%) individuals, followed by 522 bees (26%). Pollinator abundance was twice as high in the private enclosure compared to the communal dry grazing area (χ2 = 27.63, P < 0.001). We found a strong positive correlation between floral and pollinator abundances (r = 0.68, P = 0.015) but not for pollinator species richness and diversity. Bee species abundance and diversity were also significantly higher (χ2 = 68.00, P < 0.0001) in enclosures compared to open rangelands and were significantly influenced by season (χ2 = 220.73, P < 0.0001). Apis mellifera (honey bee) and Lasioglossum of the subgenus Ipomalictus were the most abundant bee species with 107 (21%) and 105 (20%) individuals, respectively. We noticed a significant interaction between season and management on influencing bee pollinator numbers (χ2 = 19.84, P = 0.0002). We conclude that traditional rangeland management can strongly influence pollinator abundance and communities. Our study will aid in developing rangeland management strategies to promote conservation of and enhance pollinator availability in tropical rangelands.

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