| 1. |
- Irminger Street, Therese, et al.
(författare)
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Removal of woody vegetation from uncultivated field margins is insufficient to promote non-woody vascular plant diversity
- 2015
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Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 1873-2305 .- 0167-8809. ; 201, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Uncultivated field margins are one of the most frequent non-crop habitat types in contemporary, highintensity agricultural landscapes and may therefore be important for the persistence of many farmland species. Managing field margins in a way that preserves, and preferably enhances, their value for biodiversity is therefore important. In the present study, we evaluate how the flora of uncultivated field margins is affected by the removal of woody vegetation as prescribed by an agri-environment scheme (AES) under the Swedish Rural Development Program 2007–2013. We used generalized linear mixed models and detrended correspondence analysis to compare the flora of open (cleared) and more overgrown field margins, located within agricultural landscapes of different complexity, in Scania, S. Sweden. As expected, there was a negative effect of management on woody species. However, the local (1m2) and transect (100 m) level richness of non-woody species did not differ significantly between management categories, and there were no differences in the within-transect variability of non-woody species (local b diversity) or the species composition (0.25m2 plots) in managed and unmanaged field margins. Our results show that the removal of woody vegetation from uncultivated field margins, as prescribed by the evaluated AES, is unlikely to benefit non-woody plant species. The species composition of the sampled field margins suggests that inclusion of appropriate field layer management alone is unlikely to be sufficient to improve habitat conditions for grassland species unless measures are taken to counteract eutrophication. Landscape type, on the other hand, influenced both the total richness and the richness of each of the species groups that were considered to be of particular conservation value in the present study: field margins in the complex agricultural landscapes were significantly richer than those in the simple ones. Maintaining non-crop habitat at the landscape scale is likely to be a necessary first step in the prevention of a further decline of farmland plants.
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| 2. |
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| 3. |
- Dalmayne, Jonas, et al.
(författare)
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Assessment of fine-scale plant species beta diversity using WorldView-2 satellite spectral dissimilarity
- 2013
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Ingår i: Ecological Informatics. - : Elsevier BV. - 1574-9541. ; 18:november, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Plant species beta diversity is influenced by spatial heterogeneity in the environment. This heterogeneity can potentially be characterised with the help of remote sensing. We used WorldView-2 satellite data acquired over semi-natural grasslands on The Baltic island of Öland (Sweden) to examine whether dissimilarities in remote sensing response were related to fine-scale, between-plot dissimilarity (beta diversity) in non-woody vascular plant species composition within the grasslands. Fieldwork, including the on-site description of a set of 30 2 m × 2 m plots and a set of 30 4 m × 4 m plots, was performed to record the species dissimilarity between pairs of same-sized plots. Spectral data were extracted by associating each plot with a suite of differently sized pixel windows, and spectral dissimilarity was calculated between pairs of same-sized pixel windows. Relationships between spectral dissimilarity and beta diversity were analysed using univariate regression and partial least squares regression. The study revealed significant positive relationships between spectral dissimilarity and fine-scale (2 m × 2 m and 4 m × 4 m) between-plot species dissimilarity. The correlation between the predicted and the observed species dissimilarity was stronger for the set of large plots (4 m × 4 m) than for the set of small plots (2 m × 2 m), and the association between spectral and species data at both plot scales decreased when pixel windows larger than 3 × 3 pixels were used. We suggest that the significant relationship between spectral dissimilarity and species dissimilarity is a reflection of between-plot environmental heterogeneity caused by differences in grazing intensity (which result in between-plot differences in field-layer height, and amounts of biomass and litter). This heterogeneity is reflected in dissimilarities in both the species composition and the spectral response of the grassland plots. Between-plot dissimilarities in both spectral response and species composition may also be caused by between-plot variations in edaphic conditions. Our results indicate that high spatial resolution satellite data may potentially be able to complement field-based recording in surveys of fine-scale species diversity in semi-natural grasslands.
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| 5. |
- de Bello, Francesco, et al.
(författare)
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Evidence for scale- and disturbance-dependent trait assembly patterns in dry semi-natural grasslands
- 2013
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Ingår i: Journal of Ecology. - : Wiley. - 1365-2745 .- 0022-0477. ; 101:5, s. 1237-1244
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Tidskriftsartikel (refereegranskat)abstract
- 1. The mechanisms driving nonrandom assembly patterns in plant communities have long been of interest in ecological research. Competing ecological theories predict that coexisting species may either be more functionally dissimilar than expected by chance (with functional divergence' mainly reflecting niche differentiation) or be functionally more similar than expected (with functional convergence' reflecting either the outcome of environmental filtering or weaker-competitor exclusion effects). Assembly patterns are usually assessed at a single scale and disturbance regime, whereas considering different spatial scales and disturbance regimes may clarify the underlying assembly mechanisms. 2. We tested the prediction that convergence and divergence are scale- and disturbance- dependent in grazed and abandoned species-rich dry grasslands within a 22km(2) landscape in south-eastern Sweden. Convergence and divergence were tested for plant species' traits and phylogenetic relationships at three nested spatial scales: within 412 plots (50x50cm, divided into 10x10cm subplots), within 117 grassland patches (from 0.02 to 11.63ha) and within the whole landscape (across patches). 3. At the finest scale (10x10cm subplots within plots), coexisting species were more different than expected by chance (divergence), both functionally and phylogenetically, suggesting niche differentiation. At the intermediate scale (50x50cm plots within patches), coexisting species showed convergence, suggesting environmental filtering. No significant deviations from random expectations were detected at the broadest scale (patches within the 22km(2) landscape) - suggesting the prevalence of dispersal limitation at this scale. The fact that nonrandom patterns were particularly evident under grazed conditions is consistent with the prediction that assembly patterns are disturbance dependent. 4. Synthesis. This study shows that multiple trait-based assembly processes operate simultaneously in species-rich communities, across spatial scales and disturbance regimes. The results support earlier theoretical predictions that divergence between coexisting species may be an important driver of community assembly, particularly at finer spatial scales, where species compete for the same local resources. In contrast, environmental filtering is expected at broader spatial scales, where species growing in particular environmental conditions share traits that are adaptive under those conditions. Within given habitat types, dispersal limitation may, however, override environmental filtering at increasing spatial scales of observation.
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| 6. |
- Dengler, Juergen, et al.
(författare)
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GrassPlot - a database of multi-scale plant diversity in Palaearctic grasslands
- 2018
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Ingår i: Phytocoenologia. - : Schweizerbart. - 0340-269X. ; 48:3, s. 331-347
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Tidskriftsartikel (refereegranskat)abstract
- GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). GrassPlot collects plot records (releves) from grasslands and other open habitats of the Palaearctic biogeographic realm. It focuses on precisely delimited plots of eight standard grain sizes (0.0001; 0.001;... 1,000 m(2)) and on nested-plot series with at least four different grain sizes. The usage of GrassPlot is regulated through Bylaws that intend to balance the interests of data contributors and data users. The current version (v. 1.00) contains data for approximately 170,000 plots of different sizes and 2,800 nested-plot series. The key components are richness data and metadata. However, most included datasets also encompass compositional data. About 14,000 plots have near-complete records of terricolous bryophytes and lichens in addition to vascular plants. At present, GrassPlot contains data from 36 countries throughout the Palaearctic, spread across elevational gradients and major grassland types. GrassPlot with its multi-scale and multi-taxon focus complements the larger international vegetationplot databases, such as the European Vegetation Archive (EVA) and the global database " sPlot". Its main aim is to facilitate studies on the scale-and taxon-dependency of biodiversity patterns and drivers along macroecological gradients. GrassPlot is a dynamic database and will expand through new data collection coordinated by the elected Governing Board. We invite researchers with suitable data to join GrassPlot. Researchers with project ideas addressable with GrassPlot data are welcome to submit proposals to the Governing Board.
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| 7. |
- Hall, Karin, et al.
(författare)
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Inventorying management status and plant species richness in semi-natural grasslands using high spatial resolution imagery
- 2010
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Ingår i: Applied Vegetation Science. - 1402-2001. ; 13:2, s. 221-233
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Tidskriftsartikel (refereegranskat)abstract
- Question Can we reliably estimate grazing intensity, indicators of grazing intensity (i.e. field-layer height and shrub-cover), and vascular plant species richness in semi-natural grasslands from high spatial resolution satellite data? Location The Baltic Island of Oland (Sweden). Methods Fieldwork included the on-site description of grazed and ungrazed areas and shrub-cover within 107 semi-natural grassland sites. Field-layer height and vascular plant species richness (total within-site and mean small-scale species richness) were recorded within the sites. Digital classification of QuickBird data was performed to identify grazed and ungrazed areas and shrub-cover. Vegetation indices were generated to analyze the performance of satellite data for estimating field-layer height, and the spectral heterogeneity was used to characterize the within-site environmental heterogeneity. Results The proportion of digitally classified grazed area explained 45% of the variation in field-layer height and 43% of the variation in shrub-cover. Field-layer height was significantly related to vegetation indices. A linear model with three explanatory variables (spectral richness(red), spectral richness(NIR), and shrub-cover) explained 47% of the variation in total within-site species richness. Conclusions High spatial resolution imagery may assist in the monitoring of the processes that follow the cessation of grazing, on the scale of individual grassland sites. Measures of spectral heterogeneity acquired by high spatial resolution imagery can be used in the assessment of total within-site vascular plant species richness in semi-natural grassland vegetation.
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| 8. |
- Hall, Karin, et al.
(författare)
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Spectral heterogeneity of QuickBird satellite data is related to fine-scale plant species spatial turnover in semi-natural grasslands
- 2012
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Ingår i: Applied Vegetation Science. - 1402-2001. ; 15:1, s. 145-157
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Question: Can satellite data be related to fine-scale species diversity and does the integrated use of field and satellite data provide information that can be used in the estimation of fine-scale species diversity in semi-natural grassland sites? Location: The Baltic Island of Oland (Sweden). Methods: Field work including the on-site description of 62 semi-natural grassland sites (represented by three 0.5m0.5m plots per site) was performed to record response variables (total species richness, mean species richness and species spatial turnover) and field-measured explanatory variables (field-layer height and distance between plots). Within each site, QuickBird satellite data were extracted from a standardized sample area by associating each field plot with a 33 pixel window (1 pixel = 2.4m2.4 m). Explanatory variables (the normalized difference vegetation index and spectral heterogeneity) were generated from the satellite data. Correlation tests, univariate regressions, variance partitioning and multivariate linear regressions were used to analyse the associations between response and explanatory variables. Results: There was a significant association between the spectral heterogeneity of the near-infrared band and the field-measured spatial turnover of species. The most parsimonious explanatory model for each response variable included both field-measured and satellite-generated explanatory variables. The models explained 30–35% of the variation in species diversity (total richness 36%, mean richness 31%, species turnover 33%). Conclusions: High spatial resolution satellite data are capable of supplying fine-scale habitat information that is relevant for the monitoring and conservation management of fine-scale plant diversity in semi-natural grasslands.
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| 9. |
- Irminger Street, Therese, et al.
(författare)
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Predicted effects of management on vascular plant species in arable field margins
- 2010
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Ingår i: Aspects of Applied Biology. - 0265-1491. ; 100, s. 233-243
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Tidskriftsartikel (refereegranskat)abstract
- Many of Sweden’s red listed species are found in the agricultural landscape. Small biotopes (e.g. field margins and field islets) are important for the maintenance of biodiversity in agricultural landscapes, and agri-environmental support is paid to farmers who keep them open. However, a proper evaluation of the biodiversity-gains from this type of management is lacking. We examined the predicted response of vascular plant species in field margins in Scania, S. Sweden, to the removal of woody vegetation and found that more species are expected to show a positive than a negative response to this type of management. Comparison of present-day and historical (1940s) aerial photographs shows that field size and the amount of small biotopes have decreased while the cover of woody vegetation on many of the remaining small biotopes has increased. Changes are greater in the arable plains and in the mixed district than in the forest district.
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| 10. |
- Johansson, Lotten, et al.
(författare)
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Semi-natural grassland continuity, long-term land-use change and plant species richness in a local agricultural landscape on Öland, Sweden
- 2008
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Ingår i: Landscape and Urban Planning. - : Elsevier BV. - 0169-2046 .- 1872-6062. ; :84, s. 200-211
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Tidskriftsartikel (refereegranskat)abstract
- The study characterizes historical land-use change and the development of semi-natural grassland habitats, over 274 years, within a mosaic agricultural landscape (22 km2) on the island of O¨ land (Sweden). We also explore the relationship between previous land-use, habitat continuity and present-day vascular plant species richness in grassland patches.Land-cover maps, based on cadastral maps and aerial photographs, wereproduced for six time-periods between 1723/1733 and 1994/1997. In 1723/1733, the landscape was dominated by grasslands, with arable land surrounding the villages. The grassland area decreased throughout the study period and grassland patches became progressively more fragmented.Present-day grasslands represent 18% of the grassland area in 1723/1733. The land-use structure of the early 18th century is still evident in the modern landscape. The majority of the present-day grasslands are situated on former common grazing land and have had a continuity of at least 274 years: the remaining grasslands are younger and developed during the 20th century on arable or forested land.The proportion of plant speciesthat depend on grazing and are characteristic of semi-natural grasslands significantly reflects the continuity and previous land-use of grassland sites. The study illustrates the way in which information on historical land-use and habitat continuity can help to explain the structuring of plant assemblages in semi-natural grasslands within the modern landscape.
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