Land use changes has led to a decline of diversity of plants in agriculture landscapes. Some of the plant species may still grow in small remnant habitats that are excluded from the cultivation. Small areas that are left, squeezed in between crop fields and forest as a border or surrounded of field as a midfield-islet. These small remnant habitats has a history of being grazed from a time when the grazing animals was grazing all over the landscape around farms. Small remnant habitats are likely to play an important role in agriculture landscapes in preserving biodiversity, associated with species richness and ecosystem functions for the future.

My research is about small remnant habitats of grassland and their additive value to biodiversity, when it comes to plants, shrubs and deciduous trees, and ecosystem functions in human modified landscapes.  I focus on how different factors (for example fragmentation, isolation and management) affect the function of small habitats in agriculture landscapes.

A selection from Stockholm University publication database

• Regional-scale land-cover change during the 20th century and its consequences for biodiversity

  2015. Sara A. O. Cousins (et al.). Ambio 44, s17-S27

  Article

  Extensive changes in land cover during the 20th century are known to have had detrimental effects on biodiversity in rural landscapes, but the magnitude of change and their ecological effects are not well known on regional scales. We digitized historical maps from the beginning of the 20th century over a 1652 km(2) study area in southeastern Sweden, comparing it to modern-day land cover with a focus on valuable habitat types. Semi-natural grassland cover decreased by over 96 % in the study area, being largely lost to afforestation and silviculture. Grasslands on finer soils were more likely to be converted into modern grassland or arable fields. However, in addition to remaining semi-natural grassland, today's valuable deciduous forest and wetland habitats were mostly grazed grassland in 1900. An analysis of the landscape-level biodiversity revealed that plant species richness was generally more related to the modern landscape, with grazing management being a positive influence on species richness.

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• The contribution of patch-scale conditions is greater than that of macroclimate in explaining local plant diversity in fragmented forests across Europe

  2015. Alicia Valdés (et al.). Global Ecology and Biogeography 24 (9), 1094-1105

  Article

  AimMacroclimate is a major determinant of large-scale diversity patterns. However, the influence of smaller-scale factors on local diversity across large spatial extents is not well documented. Here, we quantify the relative importance of local (patch-scale), landscape-scale and macroclimatic drivers of herbaceous species diversity in small forest patches in agricultural landscapes across Europe. LocationDeciduous forest patches in eight regions along a macroclimatic gradient from southern France to central Sweden and Estonia. MethodsThe diversity of forest specialists and generalists at three levels (whole forest patch, sampling plots within patches and between scales) was related to patch-scale (forest area, age, abiotic and biotic heterogeneity), landscape-scale (amount of forest, grasslands and hedgerows around the patch, patch isolation) and macroclimatic variables (temperature and precipitation) using generalized linear mixed models and variation partitioning for each group of variables. ResultsThe total amount of explained variation in diversity ranged from 8% for plot-scale diversity of generalists to 54% for patch-scale diversity of forest specialists. Patch-scale variables always explained more than 60% of the explained variation in diversity, mainly due to the positive effect of within-patch heterogeneity on patch-scale and between-scale diversities and to the positive effect of patch age on plot-scale diversity of forest specialists. Landscape-scale variables mainly contributed to the amount of explained variation in plot-scale diversity, being more important for forest specialists (21%) than for generalists (18%). Macroclimatic variables contributed a maximum of 11% to the plot-scale diversity of generalists. Main conclusionsMacroclimate poorly predicts local diversity across Europe, and herbaceous diversity is mainly explained by habitat features, less so by landscape structure. We show the importance of conserving old forest patches as refugia for typical forest species, and of enhancing the landscape context around the patches by reducing the degree of disturbance caused by agriculture.

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• Island biogeography theory outweighs habitat amount hypothesis in predicting plant species richness in small grassland remnants

  2017. Jessica P. Lindgren, Sara A. O. Cousins. Landscape Ecology 32 (9), 1895-1906

  Article

  Context

  The habitat amount hypothesis has rarely been tested on plant communities. It remains unclear how habitat amount affect species richness in habitat fragments compared to island effects such as isolation and patch size.

  Objectives

  How do patch size and spatial distribution compared to habitat amount predict plant species richness and grassland specialist plant species in small grassland remnants? How does sampling area affect the prediction of spatial variables on species richness?

  Methods

  We recorded plant species density and richness on 131 midfield islets (small remnants of semi-natural grassland) situated in 27 landscapes in Sweden. Further, we tested how habitat amount, compared to focal patch size and distance to nearest neighbor predicted species density and richness of plants and of grassland specialists.

  Results

  A total of 381 plant species were recorded (including 85 grassland specialist species). A combination of patch size and isolation was better in predicting both density and richness of species compared to habitat amount. Almost 45% of species richness and 23% of specialist species were explained by island biogeography parameters compared to 19 and 11% by the amount of habitat. A scaled sampling method increased the explanation level of island biogeography parameters and habitat amount.

  Conclusions

  Habitat amount as a concept is not as good as island biogeography to predict species richness in small habitats. Priority in landscape planning should be on larger patches rather than several small, even if they are close together. We recommend a sampling area scaled to patch size in small habitats.

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• Local conditions in small habitats and surrounding landscape are important for pollination services, biological pest control and seed predation

  2018. Jessica Lindgren, Regina Lindborg, Sara A. O. Cousins. Agriculture, Ecosystems & Environment 251, 107-113

  Article

  Small semi-natural and natural habitats in agricultural landscapes are important for biodiversity. With modern and more intensive agricultural practices they have become smaller (less than 1600 m²) and more isolated study which also affects ecosystem functions. Most ecosystem function studies using field experiments focus on a single function. Here, we investigate three functions in the same landscape at the same time. We investigated how local (trees, shrubs and grass-cover in small remnant habitats) and landscape factors (amount of and distance from key habitats i.e. forest and semi-natural grasslands) affect pollination, biological pest control and seed predation. We applied a multifunctional approach using different organisms to analyze pollination success (Primula veris), predation on aphid pests (Rhopalosiphum padi) and seed predation (of Helianthus annuus). A set-up of 3 different experiments were placed in situ on 12 midfield islets. Pollination was more affected by local factors than landscape factors, although pollination success was improved by a smaller proportions of surrounding crop fields. Seed predation was higher on islets with more surrounding forest and also with more trees on the habitat, especially close to shrubs, compared to more open areas of habitat. Predation on aphids decreased on midfield islets with a larger amount of nearby forest but was positively affected by increasing local tree cover on the habitat.

  We show that managing semi-open habitats that are connected to other natural or semi-natural habitats can improve pollination success and biological pest and weed control, thus potentially increasing yield in surrounding crop fields.

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• The complexity of forest borders determines the understory vegetation

  2018. Jessica Lindgren, Adam Kimberley, Sara A. O. Cousins. Applied Vegetation Science 21 (1), 85-93

  Article

  Questions: What are the most important drivers of plant species richness (γ-diversity) and species turnover (β-diversity) in the field layer of a forest edge? Does the tree and shrub species richness structure and complexity affect the richness of forest and grassland specialist species?

  Location: South-eastern Sweden.

  Methods: We sampled 50 forest edges with different levels of structural complexity in agricultural landscapes. In each border we recorded trees, shrubs and herb layer species in a 50 m transect parallel with the forest. We investigated species composition and species turnover in relationship to the proportions of gaps the border, the diversity of trees and shrubs and distance to semi-natural grasslands.

  Results: Total plant species richness in the field layer was mainly explained by the proportion of gaps to areas with full canopy cover, and tree diversity. Increasing number of gaps promoted higher diversity of grassland specialist species within the field layer, resulting in open forest borders with the highest overall species richness. Gaps did however have a negative impact on forest species richness. Conversely, increasing forest species richness was positively related to tree diversity but number of grassland specialist species was negatively affected by tree diversity.

  Conclusions: Managing forest borders, and therefore increasing the area of semi-open habitats in fragmented agricultural landscapes, gives future opportunities to create a network of suitable habitats for both grassland and deciduous forest specialist species. Such measures therefore have the potential to increase functional connectivity and support dispersal of species in homogeneous forest/agriculture landscapes.

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• Immigration credit of temperate forest herbs in fragmented landscapes—Implications for restoration of habitat connectivity

  2021. Jörg Brunet (et al.). Journal of Applied Ecology 58 (10), 2195-2206

  Article

  1. In many agricultural landscapes, it is important to restore networks of forests to provide habitat and stepping stones for forest specialist taxa. More knowledge is, however, needed on how to facilitate the immigration of such taxa in restored forest patches. Here, we present the first chronosequence study to quantify the dynamics of immigration credits of forest specialist plants in post-arable forest patches.
  2. We studied the distribution of herbaceous forest specialist plant species in 54 post-arable broadleaved forest patches along gradients of age (20–140 years since forest establishment), distance from ancient forest (0–2,600 m) and patch area (0.5–9.6 ha). With linear mixed models, we estimated the effects of these factors on species richness, patch means of four dispersal-related plant traits and with generalized linear models on the occurrence of 20 individual species.
  3. Post-arable forest patch age and spatial isolation from ancient forest, but not patch size, were important predictors for species richness of forest specialists, suggesting that also small patches are valuable for habitat connectivity. Compared to species richness in ancient forest stands, the immigration credit was reduced by more than 90% after 80 years in post-arable forest patches contiguous to ancient forest compared to 40% after 80 years and 60% after 140 years in isolated patches (at least 100 m to next forest). Tall-growing species with adaptations to long-distance dispersal were faster colonizers, whereas species with heavy diaspores and clonal growth were slower to colonize.
  4. Synthesis and applications. We show that post-arable oak plantations have a high potential for restoration of forest herb vegetation. Dispersal-related plant traits play a key role in explaining interspecific differences among forest specialists. To facilitate forest herb immigration across all functional groups in agricultural landscapes, we suggest to create clusters of relatively small new forest patches nearby older forest with source populations.

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• High ecosystem service delivery potential of small woodlands in agricultural landscapes

  2020. Alicia Valdés (et al.). Journal of Applied Ecology 57 (1), 4-16

  Article

  Global forest loss and fragmentation have strongly increased the frequency of forest patches smaller than a few hectares. Little is known about the biodiversity and ecosystem service supply potential of such small woodlands in comparison to larger forests. As it is widely recognized that high biodiversity levels increase ecosystem functionality and the delivery of multiple ecosystem services, small, isolated woodlands are expected to have a lower potential for ecosystem service delivery than large forests hosting more species. We collected data on the diversity of six taxonomic groups covering invertebrates, plants and fungi, and on the supply potential of five ecosystem services and one disservice within 224 woodlands distributed across temperate Europe. We related their ability to simultaneously provide multiple ecosystem services (multiservice delivery potential) at different performance levels to biodiversity of all studied taxonomic groups (multidiversity), forest patch size and age, as well as habitat availability and connectivity within the landscape, while accounting for macroclimate, soil properties and forest structure. Unexpectedly, despite their lower multidiversity, smaller woodlands had the potential to deliver multiple services at higher performance levels per area than larger woodlands of similar age, probably due to positive edge effects on the supply potential of several ecosystem services. Biodiversity only affected multiservice delivery potential at a low performance level as well as some individual ecosystem services. The importance of other drivers of ecosystem service supply potential by small woodlands in agricultural landscapes also depended on the level of performance and varied with the individual ecosystem service considered. Synthesis and applications. Large, ancient woodlands host high levels of biodiversity and can therefore deliver a number of ecosystem services. In contrast, smaller woodlands in agricultural landscapes, especially ancient woodlands, have a higher potential to deliver multiple ecosystem services on a per area basis. Despite their important contribution to agricultural landscape multifunctionality, small woodlands are not currently considered by public policies. There is thus an urgent need for targeted policy instruments to ensure their adequate management and future conservation in order to either achieve multiservice delivery at high levels or to maximize the delivery of specific ecosystem services.

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Show all publications by Jessica Lindgren at Stockholm University