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| 2. |
- Siefert, Andrew, et al.
(författare)
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A global meta-analysis of the relative extent of intraspecific trait variation in plant communities
- 2015
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 18:12, s. 1406-1419
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Forskningsöversikt (refereegranskat)abstract
- Recent studies have shown that accounting for intraspecific trait variation (ITV) may better address major questions in community ecology. However, a general picture of the relative extent of ITV compared to interspecific trait variation in plant communities is still missing. Here, we conducted a meta-analysis of the relative extent of ITV within and among plant communities worldwide, using a data set encompassing 629 communities (plots) and 36 functional traits. Overall, ITV accounted for 25% of the total trait variation within communities and 32% of the total trait variation among communities on average. The relative extent of ITV tended to be greater for whole-plant (e.g. plant height) vs. organ-level traits and for leaf chemical (e.g. leaf N and P concentration) vs. leaf morphological (e.g. leaf area and thickness) traits. The relative amount of ITV decreased with increasing species richness and spatial extent, but did not vary with plant growth form or climate. These results highlight global patterns in the relative importance of ITV in plant communities, providing practical guidelines for when researchers should include ITV in trait-based community and ecosystem studies.
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| 3. |
- Ekroos, Johan, et al.
(författare)
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Sparing land for biodiversity at multiple spatial scales
- 2016
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- A common approach to the conservation of farmland biodiversity and the promotion of multifunctional landscapes, particularly in landscapes containing only small remnants of non-crop habitats, has been to maintain landscape heterogeneity and reduce land-use intensity. In contrast, it has recently been shown that devoting specific areas of non-crop habitats to conservation, segregated from high-yielding farmland (“land sparing”), can more effectively conserve biodiversity than promoting low-yielding, less intensively managed farmland occupying larger areas (“land sharing”). In the present paper we suggest that the debate over the relative merits of land sparing or land sharing is partly blurred by the differing spatial scales at which it is suggested that land sparing should be applied. We argue that there is no single correct spatial scale for segregating biodiversity protection and commodity production in multifunctional landscapes. Instead we propose an alternative conceptual construct, which we call “multiple-scale land sparing,” targeting biodiversity and ecosystem services in transformed landscapes. We discuss how multiple-scale land sparing may overcome the apparent dichotomy between land sharing and land sparing and help to find acceptable compromises that conserve biodiversity and landscape multifunctionality.
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| 4. |
- Reitalu, Triin, et al.
(författare)
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Plant species segregation on different spatial scales in semi-natural grasslands
- 2008
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Ingår i: Journal of Vegetation Science. - : John Wiley & Sons. - 1100-9233 .- 1654-1103. ; 19:3, s. 407-416
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Tidskriftsartikel (refereegranskat)abstract
- Question: We studied the patterns of plant species co-occurrence on three, nested, spatial scales in semi-natural grassland communities and explored the possible ecological processes underlying the patterns. Location: Dry, semi-natural grasslands in a 4.5 km x 4.5 km area on the Baltic Island of Oland (Sweden). Methods: The study used replicated samples on three, nested, spatial scales: 50 cm x 50 cm plots (N= 516), grassland patches (N = 109) and the whole landscape (N= 6). We used a null model approach to study species co-occurrence patterns and compared the ecological amplitudes of the pairs of species contributing most to the patterns. We used linear models to search for associations between species segregation and environmental and landscape factors. Results and Conclusions: Our results support the prediction that patterns of species co-occurrence are likely to be influenced by different mechanisms on different spatial scales. On the plot scale, we interpreted the species segregation in terms of species interactions. The degree of species segregation was significantly associated with the plots'positions within the grassland patches (edge effects) and with management intensity of the grasslands - both variables can be assumed to influence species interactions. On the grassland patch scale, we interpreted the species segregation in terms of within-patch environmental heterogeneity. The degree of segregation was significantly associated with the area of the grassland patches and with management intensity - both variables that are likely to be related to environmental heterogeneity within the grasslands. Species segregation on the landscape scale was interpreted in terms of environmental heterogeneity among grassland patches and was significantly associated with land-use history
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| 5. |
- Reitalu, Triin, et al.
(författare)
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Small-scale plant species richness and evenness in semi-natural grasslands respond differently to habitat fragmentation
- 2009
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Ingår i: Biological Conservation. - : Elsevier BV. - 1873-2917 .- 0006-3207. ; 142:4, s. 899-908
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Tidskriftsartikel (refereegranskat)abstract
- The study explores whether small-scale species diversity, species evenness and species richness in semi-natural grassland communities are similarly associated with present management regime and/or present and historical landscape context (percentage of different land-cover types in the surroundings). Species diversity, evenness and richness were recorded within 44150 x 50 cm grassland plots in a 4.5 x 4.5 km agricultural landscape on bland, Sweden. Recent and historical land-cover maps (years 2004, 1959, 1938, 1835, and 1800) were used to characterize the present and past landscape context of the sampled vegetation plots. Partial regression and simultaneous autoregressive models were used to explore the relationships between species diversity measures (Shannon diversity, richness and evenness) and different explanatory variables while accounting for spatial autocorrelation in the data. The results indicated that species richness was relatively sensitive to grassland isolation, while the response of species evenness to isolation was characterized by a degree of inertia. Because the richness and evenness components of species diversity may respond differently to habitat fragmentation, we suggest that monitoring projects and empirical studies that focus on changes in biodiversity in semi-natural grasslands should include the assessment of species evenness - as a complement to the assessment of species richness. In addition, our results indicated that the development and persistence of a species-rich and even grassland vegetation was favoured in areas that have historically (in the 19th century) been surrounded by grasslands. Information on landscape history should, whenever possible, be incorporated into the planning of strategies for grassland conservation. (C) 2008 Elsevier Ltd. All rights reserved.
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| 6. |
- Biurrun, Idoia, et al.
(författare)
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Benchmarking plant diversity of Palaearctic grasslands and other open habitats
- 2021
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Ingår i: Journal of Vegetation Science. - Oxford : John Wiley & Sons. - 1100-9233 .- 1654-1103. ; 32:4
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Tidskriftsartikel (refereegranskat)abstract
- Journal of Vegetation Science published by John Wiley & Sons Ltd on behalf of International Association for Vegetation Science.Aims: Understanding fine-grain diversity patterns across large spatial extents is fundamental for macroecological research and biodiversity conservation. Using the GrassPlot database, we provide benchmarks of fine-grain richness values of Palaearctic open habitats for vascular plants, bryophytes, lichens and complete vegetation (i.e., the sum of the former three groups). Location: Palaearctic biogeographic realm. Methods: We used 126,524 plots of eight standard grain sizes from the GrassPlot database: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1,000 m2 and calculated the mean richness and standard deviations, as well as maximum, minimum, median, and first and third quartiles for each combination of grain size, taxonomic group, biome, region, vegetation type and phytosociological class. Results: Patterns of plant diversity in vegetation types and biomes differ across grain sizes and taxonomic groups. Overall, secondary (mostly semi-natural) grasslands and natural grasslands are the richest vegetation type. The open-access file ”GrassPlot Diversity Benchmarks” and the web tool “GrassPlot Diversity Explorer” are now available online (https://edgg.org/databases/GrasslandDiversityExplorer) and provide more insights into species richness patterns in the Palaearctic open habitats. Conclusions: The GrassPlot Diversity Benchmarks provide high-quality data on species richness in open habitat types across the Palaearctic. These benchmark data can be used in vegetation ecology, macroecology, biodiversity conservation and data quality checking. While the amount of data in the underlying GrassPlot database and their spatial coverage are smaller than in other extensive vegetation-plot databases, species recordings in GrassPlot are on average more complete, making it a valuable complementary data source in macroecology. © 2021 The Authors.
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| 7. |
- Lönn, Mikael, et al.
(författare)
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Gene diversity and demographic turnover in central and peripheral populations of the perennial herb, Gypsophila fastigiata
- 2002
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 99:3, s. 489-498
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Tidskriftsartikel (refereegranskat)abstract
- Within-population gene diversity (HS) was estimated (using allozyme markers) for 16 populations of the perennial, outcrossing plant, Gypsophila fastigiata, on the Baltic island of Öland. The populations were characterized by data on extent, density, life-stages, and habitat diversity. Populations were classed as central or peripheral in relation to the distribution of “alvar” (habitats with shallow, calcareous soils on limestone bedrock) on southern Öland. Three minimal adequate models were used to explain HS and the proportions of juveniles and dead adults. In the first model, HS was significantly lower in peripheral populations and there were no significant additional effects of other explanatory variables. The lower diversity in peripheral populations can be explained by a combination of genetic drift (in populations that vary in size in response to habitat fragmentation) and lower levels of interpopulation gene flow than in central populations. In the two life-stage models, peripheral populations had significantly larger proportions of both juveniles and dead adults – indicating a greater demographic turnover than in the central populations. There were also significant effects of HS and species diversity on the proportion of juveniles. The central or peripheral position of populations is the strongest predictor of both within-population gene diversity and life-stage dynamics in Öland G. fastigiata.
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| 8. |
- Olle, Jonsson B., et al.
(författare)
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Allozyme diversity and geographic variation in the widespread coastal sedge, Carex arenaria
- 2000
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Ingår i: Diversity & distributions. - : Wiley. - 1366-9516 .- 1472-4642. ; 6:2, s. 65-80
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Tidskriftsartikel (refereegranskat)abstract
- Allozyme electrophoresis was used to investigate the structure of genetic variation in the rhizomatous coastal sedge, Carex arenaria, throughout its European range - from the SW Iberian peninsula to the Baltic region. Material was sampled from 77 sites in five geographic regions. Nine of the 13 investigated loci were polymorphic in the total material and there were interregional differences in the number of polymorphic loci per site and the percentage of variable sites. In the Scandinavia/Baltic region only 61% of the sites contained at least one locus with more than one allele, whereas all the British and SW Iberian sites were variable. There was a general tendency for the regional frequencies of the less common alleles at individual loci to decline from SW to NE. The mean (over loci and sites) within-site gene diversity (H(site)) was 0.064 (in calculations based on the number of observed multilocus allozyme genotypes within each sampling site). Although there was considerable variation between geographically adjacent sites, within-site diversity showed a general decrease from SW to NE in Europe. There were significant differences in within-region gene diversity (H(reg)) for the four most variable loci between the five regions. H(reg) generally decreased from SW to NE Europe and most loci showed the highest diversity in the SW Iberian peninsula and the Bay of Biscay regions. The mean (over loci) gene diversity in the total material (H(tot)) was 0.070 and the levels of diversity in Carex arenaria are substantially lower than is usual in rhizomatous sedges. The within-site, between-site and between-regional components of the total diversity were 92.4%, 2.5% and 5.1%, respectively. The low levels of overall gene diversity in C. arenaria and the successive decrease in diversity from SW to NE are interpreted in terms of the species' history of post-glacial spread into northern Europe. Despite the overall northwards decrease in diversity, the widespread occurrence of less common alleles and the lack of regional deviations from Hardy-Weinberg genotype frequency expectations suggest that C. arenaria is not predominantly self-fertilized.
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| 9. |
- Prentice, Honor C, et al.
(författare)
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Changes in allozyme frequencies in Festuca ovina populations after a 9-year nutrient/water experiment
- 2000
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Ingår i: Journal of Ecology. - : Wiley. - 0022-0477 .- 1365-2745. ; 88:2, s. 331-347
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Tidskriftsartikel (refereegranskat)abstract
- 1 The grass Festuca ovina is an important constituent of the species-rich 'alvar' grasslands on the Baltic island of Oland. Levels of allozyme polymorphism are high and variation is known to be correlated with habitat variation (soil moisture, pH and depth). 2 A 9-year field experiment on species diversity provided replicate plots (in three sites) that had been subjected to six different experimental treatments (control; N + P + K; P + K; N + K; K; water). 3 Samples of F. ovina were collected and analyses of deviance were used to investigate associations between allele frequencies, at each of four polymorphic loci, and the nutrient/water treatments. We also used the models to estimate predicted values for the alleles in different nutrient/water treatments and in interactions involving the nutrient/water treatments and additional explanatory variables (vegetation height and clipping). 4 There were significant allozyme frequency differences between samples of F. ovina from the six different nutrient/water treatments in the grassland experiment. Frequencies in the fertilized or watered plots had diverged from those in the control plots. There were also significant allele-habitat associations (after the removal of site effects), especially at the Pgi-2 locus. 5 Soil moisture was the only variable that was common to this study and an earlier study of variation in F. ovina in natural habitats. In natural populations, the Pgi-2-2 allele was significantly associated with soil moisture and was more common in dry habitats. Our findings that the frequency of the Pgi-2-2 allele was significantly affected by the nutrient/water treatments, and that it was rarest in the treatment that involved the addition of extra water, were therefore as predicted. 6 The study supports the conclusion, from an earlier study of populations in unmanipulated grassland habitats, that selection is contributing to the fine-scale patterning of genetic variation in the alvar populations of F. ovina.
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| 10. |
- Prentice, Honor C., et al.
(författare)
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Gene diversity in a fragmented population of Briza media: grassland continuity in a landscape context
- 2006
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Ingår i: Journal of Ecology. - : Wiley. - 0022-0477 .- 1365-2745. ; 94:1, s. 87-97
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Tidskriftsartikel (refereegranskat)abstract
- 1. We investigated patterns of allozyme variation in demes of the grass Briza media in semi-natural grassland fragments within a mosaic agricultural landscape on the Baltic island of Öland. In the study area, Briza is both a characteristic species of old pastures and an early colonizer of young grasslands developing on previously forested or arable sites. 2 Generalized linear models revealed that descriptors of both present landscape structure and past grassland history are significant determinants of genetic variation in the Briza demes. Genetic structure and levels of within-deme diversity are influenced by the size of grassland fragments, the type of habitat surrounding the grasslands, the size/spatial extent of the demes, the geographic position of the demes and the historical continuity of the grassland fragments. 3 Gene diversity (H) was higher in demes from grassland polygons with a high proportion of adjacent grassland, higher in the more extensive demes, and decreased northwards within the study area. 4 The negative association between the inbreeding coefficient (FIS) and grassland continuity is interpreted in terms of a two-stage colonization process: recruitment into young grasslands leads initially to spatial patchiness, but subsequent selection in maturing pastures occurs within an increasingly uniform and dense sward. 5 Despite a weak overall genetic structure (as indicated by Bayesian cluster analysis) the between-deme FST was significant. Linear discriminant analysis of within-deme allele frequencies grouped the demes according to the age and previous land-use history of their grassland polygons. The convergence of the allele frequency profiles in the younger grasslands towards those of the old grasslands is consistent with convergence of selective regimes as pastures mature towards an increasingly uniform, dense sward and characteristic species assemblage. 6 The genetic composition of demes of a grassland species appears to be influenced by the process of plant community convergence during grassland development – complementing the recent finding that convergence of species composition in experimental assemblages of grassland plants is dependent on the genotypic composition of the component species
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