| 1. |
- Aggemyr, Elsa, et al.
(författare)
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Species richness and composition differ in response to landscape and biogeography
- 2018
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Ingår i: Landscape Ecology. - : Springer Science and Business Media LLC. - 0921-2973 .- 1572-9761. ; 33:12, s. 2273-2284
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Tidskriftsartikel (refereegranskat)abstract
- Context Understanding how landscape patterns affect species diversity is of great importance in the fields of biogeography, landscape ecology and conservation planning, but despite the rapid advance in biodiversity analysis, investigations of spatial effects on biodiversity are still largely focused on species richness.Objectives We wanted to know if and how species richness and species composition are differentially driven by the spatial measures dominating studies in landscape ecology and biogeography. As both measures require the same limited presence/absence information, it is important to choose an appropriate diversity measure, as differing results could have important consequences for interpreting ecological processes.Methods We recorded plant occurrences on 112 islands in the Baltic archipelago. Species richness and composition were calculated for each island, and the explanatory power of island area and habitat heterogeneity, distance to mainland and structural connectivity at three different landscape sizes were examined.Results A total of 354 different plant species were recorded. The influence of landscape variables differed depending on which diversity measure was used. Island area and structural connectivity determined plant species richness, while species composition revealed a more complex pattern, being influenced by island area, habitat heterogeneity and structural connectivity.Conclusions Although both measures require the same basic input data, species composition can reveal more about the ecological processes affecting plant communities in fragmented landscapes than species richness alone. Therefore, we recommend that species community composition should be used as an additional standard measure of diversity for biogeography, landscape ecology and conservation planning.
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| 2. |
- Albert, Aurélie, et al.
(författare)
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Seed dispersal by ungulates as an ecological filter : a trait-based meta-analysis
- 2015
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 124:9, s. 1109-1120
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Tidskriftsartikel (refereegranskat)abstract
- Plant communities are often dispersal-limited and zoochory can be an efficient mechanism for plants to colonize new patches of potentially suitable habitat. We predicted that seed dispersal by ungulates acts as an ecological filter - which differentially affects individuals according to their characteristics and shapes species assemblages - and that the filter varies according to the dispersal mechanism (endozoochory, fur-epizoochory and hoof-epizoochory). We conducted two-step individual participant data meta-analyses of 52 studies on plant dispersal by ungulates in fragmented landscapes, comparing eight plant traits and two habitat indicators between dispersed and non-dispersed plants. We found that ungulates dispersed at least 44% of the available plant species. Moreover, some plant traits and habitat indicators increased the likelihood for plant of being dispersed. Persistent or nitrophilous plant species from open habitats or bearing dry or elongated diaspores were more likely to be dispersed by ungulates, whatever the dispersal mechanism. In addition, endozoochory was more likely for diaspores bearing elongated appendages whereas epizoochory was more likely for diaspores released relatively high in vegetation. Hoof-epizoochory was more likely for light diaspores without hooked appendages. Fur-epizoochory was more likely for diaspores with appendages, particularly elongated or hooked ones. We thus observed a gradient of filtering effect among the three dispersal mechanisms. Endozoochory had an effect of rather weak intensity (impacting six plant characteristics with variations between ungulate-dispersed and non-dispersed plant species mostly below 25%), whereas hoof-epizoochory had a stronger effect (eight characteristics included five ones with above 75% variation), and fur-epizoochory an even stronger one (nine characteristics included six ones with above 75% variation). Our results demonstrate that seed dispersal by ungulates is an ecological filter whose intensity varies according to the dispersal mechanism considered. Ungulates can thus play a key role in plant community dynamics and have implications for plant spatial distribution patterns at multiple scales.
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| 3. |
- Auffret, Alistair G.
(författare)
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Can seed dispersal by human activity play a useful role for the conservation of European grasslands?
- 2011
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Ingår i: Applied Vegetation Science. - 1402-2001 .- 1654-109X. ; 14:3, s. 291-303
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To review the recent research into human-mediated dispersal (HMD) in the European rural landscape, and explore the potential positive aspect of HMD for grassland conservation, in contrast to it's common association with the spread of invasive species. Methods: A literature search was undertaken to identify HMD vectors in the rural landscape for discussion regarding dispersal potential past and present, implications for management, and the identification of future research needs. Results: Grazing animals are important propagule dispersers, but the reduced movement of livestock through the landscape has also meant a reduction in seeds dispersed in this way. Other, non-standard human-mediated dispersal vectors such as clothing and motor vehicles can also transport seeds of many species, and HMD vectors often transport seeds with a variety of dispersal specialisations. Recommendations: There should be a greater movement of grazing animals throughout the landscape, either within larger grazing areas or between existing grasslands. Where this is not possible, other, more directed dispersal of propagules from species-rich communities to target sites should be considered. The potential of non-standard HMD vectors to make a positive contribution to biodiversity should be considered, but more research into all types of HMD vectors is important if we are to fully understand their role in the dispersal of plant species in fragmented landscapes.
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| 4. |
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| 5. |
- Auffret, Alistair G., et al.
(författare)
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Grassland connectivity by motor vehicles and grazing livestock
- 2013
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Ingår i: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 36:10, s. 1150-1157
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Tidskriftsartikel (refereegranskat)abstract
- In addition to habitat loss and fragmentation, agricultural change has led to a change in seed dispersal processes in therural landscape through a loss of structural and functional connectivity. Here, human-mediated dispersal vectors areprevalent, and we explored whether the loss of connectivity via free-ranging livestock could be mitigated by the increasein roads and motor vehicles. We found that structurally, 39% of all valuable semi-natural grassland habitats in southernSweden are adjacent to public road verges, which in the rural landscape are often considered to be suitable habitat forgrassland species. Additionally, by collecting mud attached to cars and farming machinery and manure from livestock(cattle, horse, sheep) grazing semi-natural grassland pasture, we found that motor vehicles are also capable seed dispers-ers. A similar number of species were dispersed by both vectors, although the composition of samples was quite different.Motor vehicles dispersed more grassland specialists than invasive species, although in much lower abundances than didgrazing livestock. Despite these differences, motor vehicles were found to be able to disperse species with the same kindsof dispersal traits as livestock. A high number of seeds, species and specialists in manure samples means that greater move-ment of livestock is desirable to increase functional grassland connectivity. However, effective management could improvethe suitability of roadsides as grassland corridors and increase the availability of seeds for long-distance human-mediateddispersal via cars and tractors. Our results suggest that in many rural landscapes, connectivity by road networks couldhelp mediate habitat loss and fragmentation of grasslands. However, such effects can be context dependent, and the con-nectivity provided by roads could have serious negative consequences in other regions.
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| 6. |
- Auffret, Alistair G., et al.
(författare)
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Grazing networks provide useful functional connectivity for plants in fragmented systems
- 2012
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Ingår i: Journal of Vegetation Science. - : Wiley. - 1100-9233 .- 1654-1103. ; 23:5, s. 970-977
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Tidskriftsartikel (refereegranskat)abstract
- Question To what extent does the movement of animals between fragmented habitat patches provide functional connectivity via endozoochorous seed dispersal? Location The Stockholm archipelago, Sweden. Methods We followed all movements of livestock between islands during one grazing season. After each movement, manure was collected and its seed content assessed through seedling emergence. Seedling data were then compared to vegetation surveys from the grazed islands with regard to functional traits. Results Light- and nitrogen-demanding locally abundant species, and those with relatively small and persistent seeds were more likely to be moved between islands. For quantitative traits, only a subset of the available trait ranges were dispersed, with extreme values left behind. Species apparently specialized to other means of dispersal emerged from the manure samples. Neither dispersed traits nor seed density changed with timing of movement, but seed richness and diversity both increased throughout the season. The subsets of endozoochorously-dispersed species in the established vegetation were more similar than non-dispersed subsets between islands linked by livestock. Conclusions Grazing networks contribute to the connectivity of the core species in the system, and could provide useful tools for grassland management in fragmented landscapes.
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| 7. |
- Auffret, Alistair G., et al.
(författare)
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HistMapR : Rapid digitization of historical land-use maps in R
- 2017
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Ingår i: Methods in Ecology and Evolution. - 2041-210X. ; 8:11, s. 1453-1457
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Tidskriftsartikel (refereegranskat)abstract
- Habitat destruction and degradation represent serious threats to biodiversity, and quantification of land-use change over time is important for understanding the consequences of these changes to organisms and ecosystem service provision. Comparing land use between maps from different time periods allows estimation of the magnitude of habitat change in an area. However, digitizing historical maps manually is time-consuming and analyses of change are usually carried out at small spatial extents or at low resolutions. HistMapR contains a number of functions that can be used to semi-automatically digitize historical land use according to a map's colours, as defined by the RGB bands of the raster image. We test the method on different historical land-use map series and compare results to manual digitizations. Digitization is fast, and agreement with manually digitized maps of around 80-90% meets common targets for image classification. We hope that the ability to quickly classify large areas of historical land use will promote the inclusion of land-use change into analyses of biodiversity, species distributions and ecosystem services.
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| 8. |
- Auffret, Alistair G., et al.
(författare)
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Humans as Long-Distance Dispersers of Rural Plant Communities
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- Humans are known for their capacity to disperse organisms long distances. Long-distance dispersal can be important for species threatened by habitat destruction, but research into human-mediated dispersal is often focused upon few and/or invasive species. Here we use citizen science to identify the capacity for humans to disperse seeds on their clothes and footwear from a known species pool in a valuable habitat, allowing for an assessment of the fraction and types of species dispersed by humans in an alternative context. We collected material from volunteers cutting 48 species-rich meadows throughout Sweden. We counted 24 354 seeds of 197 species, representing 34% of the available species pool, including several rare and protected species. However, 71 species (36%) are considered invasive elsewhere in the world. Trait analysis showed that seeds with hooks or other appendages were more likely to be dispersed by humans, as well as those with a persistent seed bank. More activity in a meadow resulted in more dispersal, both in terms of species and representation of the source communities. Average potential dispersal distances were measured at 13 km. We consider humans capable seed dispersers, transporting a significant proportion of the plant communities in which they are active, just like more traditional vectors such as livestock. When rural populations were larger, people might have been regular and effective seed dispersers, and the net rural-urban migration resulting in a reduction in humans in the landscape may have exacerbated the dispersal failure evident in declining plant populations today. With the fragmentation of habitat and changes in land use resulting from agricultural change, and the increased mobility of humans worldwide, the dispersal role of humans may have shifted from providers of regular local and landscape dispersal to providers of much rarer long-distance and regional dispersal, and international invasion.
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| 9. |
- Auffret, Alistair G., et al.
(författare)
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Land uplift creates important meadow habitat and a potential original niche for grassland species
- 2018
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 285:1876
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Tidskriftsartikel (refereegranskat)abstract
- Semi-natural grasslands have been severely affected by agricultural land-use change. However, the isostatic land adjustment following deglaciation in the Northern Hemisphere means that new land is continually being created in coastal areas. We modelled isostatic adjustment during the last 4000 years in a region of the Baltic coast to estimate the emergence of potential grassland habitat. We also compared the alpha and beta diversity of existing managed and abandoned coastal meadows, and assessed their contribution to biodiversity at landscape scales. We estimated that half the 7866 km(2) of emerging land had the potential to become coastal meadow habitat, which is an order of magnitude larger than the total area of all valuable semi-natural grassland in the study region today. The small area of managed coastal habitat remaining was found to have a disproportionate influence on the richness of threatened species at landscape scales, but our results also show that continued management is essential for the maintenance of grassland biodiversity. Our combination of approaches identifies uplifted coastal meadows as an additional original niche for grassland plant species, while highlighting that low-intensity disturbance through grassland management is essential for the maintenance of diversity at multiple scales.
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| 10. |
- Auffret, Alistair G., et al.
(författare)
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More warm-adapted species in soil seed banks than in herb layer plant communities across Europe
- 2023
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Ingår i: Journal of Ecology. - : John Wiley & Sons. - 0022-0477 .- 1365-2745. ; 111:5, s. 1009-1020
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Tidskriftsartikel (refereegranskat)abstract
- Responses to climate change have often been found to lag behind the rate of warming that has occurred. In addition to dispersal limitation potentially restricting spread at leading range margins, the persistence of species in new and unsuitable conditions is thought to be responsible for apparent time-lags. Soil seed banks can allow plant communities to temporarily buffer unsuitable environmental conditions, but their potential to slow responses to long-term climate change is largely unknown. As local forest cover can also buffer the effects of a warming climate, it is important to understand how seed banks might interact with land cover to mediate community responses to climate change. We first related species-level seed bank persistence and distribution-derived climatic niches for 840 plant species. We then used a database of plant community data from grasslands, forests and intermediate successional habitats from across Europe to investigate relationships between seed banks and their corresponding herb layers in 2763 plots in the context of climate and land cover. We found that species from warmer climates and with broader distributions are more likely to have a higher seed bank persistence, resulting in seed banks that are composed of species with warmer and broader climatic distributions than their corresponding herb layers. This was consistent across our climatic extent, with larger differences (seed banks from even warmer climates relative to vegetation) found in grasslands. Synthesis. Seed banks have been shown to buffer plant communities through periods of environmental variability, and in a period of climate change might be expected to contain species reflecting past, cooler conditions. Here, we show that persistent seed banks often contain species with relatively warm climatic niches and those with wide climatic ranges. Although these patterns may not be primarily driven by species’ climatic adaptations, the prominence of such species in seed banks might still facilitate climate-driven community shifts. Additionally, seed banks may be related to ongoing trends regarding the spread of widespread generalist species into natural habitats, while cool-associated species may be at risk from both short- and long-term climatic variability and change.
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