| 1. |
- 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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| 2. |
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| 3. |
- Dengler, Jürgen, et al.
(författare)
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Species constancy depends on plot size - a problem for vegetation classification and how it can be solved
- 2009
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Ingår i: Journal of Vegetation Science. - : Wiley. - 1100-9233 .- 1654-1103. ; 20:4, s. 754-766
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Tidskriftsartikel (refereegranskat)abstract
- Question While it is well known that species richness depends on plot size, it is not generally recognised that the same must be true for constancy. Accordingly, many authors use varying plot sizes when classifying vegetation based on the comparison of constancies between groups of plots. We ask whether the constancy-area relationship follows a general rule, how strong the effect of plot sizes is on constancies, and if it is possible to correct constancies for area. Location For empirical evaluation, we use data from plant communities in the Czech Republic, Sweden and Russia. Methods To assess the potential influence of differences in plot size on constancies, we develop a mathematical model. Then, we use series of nested plot species richness data from a wide range of community types (herbaceous and forest) to determine the parameters of the derived function and to test how much the shape of the constancy-area relationship depends on taxa or vegetation types. Results Generally, the constancy-area relationship can be described by C (A)=1-(1-C-0)((A/A0)boolean AND d), with C being constancy, A area, C-0 known constancy on a specific area A(0), and d a damping parameter accounting for spatial autocorrelation. As predicted by this function, constancies in plant communities always varied from values near 0% to near 100% if plot sizes were changed sufficiently. For the studied vegetation types, a two- to fourfold increase in plot size resulted in a change of conventional constancy classes, i.e. an increase of constancy by 20% or more. Conclusions Vegetation classification, which largely relies on constancy values, irrespective of whether traditional or modern fidelity definitions are used, is strongly prone to distorting scale effects when releves of different plot sizes are combined in studies. The constancy-area functions presented allow an approximate transformation of constancies to other plot sizes but are flawed by idiosyncrasies in taxa and vegetation types. Thus, we conclude that the best solution for future surveys is to apply uniform plot sizes within a few a priori delimited formations and to determine diagnostic species only within these formations. Finally, we suggest that more detailed analyses of constancy-area relationships can contribute to a better understanding of species-area relationships because the latter are the summation of the first for all species.
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| 4. |
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| 5. |
- Dengler, Jürgen, et al.
(författare)
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Working group on dry grasslands in the Nordic and Baltic region – Outline of the project and first results for the class Festuco-Brometea
- 2006
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Ingår i: Annali di Botanica N.S.. - 0365-0812. ; 6, s. 73-100
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Tidskriftsartikel (refereegranskat)abstract
- The vegetation databank established by our working group covers the classes Festuco-Brometea, Koelerio-Corynephoretea, and Trifolio-Geranietea sanguinei in the Nordic and Baltic region, i.e. NE Germany, Denmark, Norway, Sweden, Finland, N Poland, Lithuania, Latvia, Estonia, and NW Russia. We aim to use these data to develop a consistent supra-national phytosociological classification of these xerothermic vegetation types in the study area and to analyse their biodiversity patterns. Up to now, we located some 12,500 relevés meeting our criteria, and more than 3,500 of them have already been included in the databank. We give an overview of the properties of these relevés as regards coverage of syntaxa and countries, source types, plot sizes, and cryptogam treatment. We also present first analyses for the basiphilous semi-dry grasslands (Brachypodietalia pinnati) within the Festuco-Brometea. For this group of communities, many different and incompatible classification schemes have been proposed. We give an overview of the alliance and association names that have been in use for them in the study area, accompanied by a nomenclatural assessment. The relevés presently included in the databank have been tentatively assigned to those vegetation classes whose diagnostic taxa were prevailing. Accordingly, more than 2,000 relevés have been placed in the Festuco-Brometea. These show considerable floristic differences compared to stands of the southern temperate Brachypodietalia pinnati alliances Bromion erecti, Cirsio-Brachypodion pinnati, and Agrostion vinealis. The presence degrees of Avenula pratensis and Homalothecium lutescens, for instance, are significantly increased in the study area, and those of Festuca rupicola and Euphorbia cyparissias decreased. An analysis of the species-area relationship yielded a power function with z = 0.09 which is considerably lower than increments determined by nested-plot analyses of this commu-nity type, indicating the probable incompleteness of the species lists for many of the larger plots. Finally, we give an outlook on the future objectives of the working group.
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| 6. |
- Idoia Biurrun, Idoia, et al.
(författare)
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GrassPlot v. 2.00 – first update on the database of multi-scale plant diversity in Palaearctic grasslands
- 2019
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Ingår i: Palaearctic Grasslands. - : Eurasian Dry Grassland Group (EDGG). - 2627-9827. ; :44, s. 26-47
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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). Following a previous Long Database Report (Dengler et al. 2018, Phytocoenologia 48, 331–347), we provide here the first update on content and functionality of GrassPlot. The current version (GrassPlot v. 2.00) contains a total of 190,673 plots of different grain sizes across 28,171 independent plots, with 4,654 nested-plot series including at least four grain sizes. The database has improved its content as well as its functionality, including addition and harmonization of header data (land use, information on nestedness, structure and ecology) and preparation of species composition data. Currently, GrassPlot data are intensively used for broad-scale analyses of different aspects of alpha and beta diversity in grassland ecosystems.
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| 7. |
- Löbel, Swantje, et al.
(författare)
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Biological traits explain bryophyte species distributions and responses to forest fragmentation and climatic variation
- 2018
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Ingår i: Journal of Ecology. - : Wiley. - 0022-0477 .- 1365-2745. ; 106, s. 1700-1713
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Tidskriftsartikel (refereegranskat)abstract
- 1. Forest ecosystems have been subjected to intensive exploitation, and on top of these land use-driven habitat alterations, there is an ongoing and rapid climate change. Understanding why environmental responses differ across species and how differences are mediated by species' traits is crucial for predicting the complex effects of global change on forest biodiversity.2. We used (1) single-species distribution models and (2) multispecies predictive fourth-corner models of varying complexity to identify critical response traits of dead wood inhabiting bryophytes and to quantify species' relationships with climatic and forest landscape variation. We hypothesized that reproductive and life-history traits would be mainly linked with forest connectivity, whereas morphological traits would mostly relate to (micro-) climatic variation.3. The inferred trait-environment relationships based on the different fourth-corner models were consistent. Unexpectedly, reproduction modes were more closely linked to climatic and habitat factors than to forest connectivity. Sexual reproduction was positively related to high temperatures and broadleaf trees, but negatively to high amounts of precipitation. The opposite was true for species which predominantly, or additionally, reproduce asexually. Bryophyte life-forms were related to both habitat and climatic conditions. The positive relationship of shoot length with both high temperatures and high amounts of precipitation suggested that competitive exclusion is important in determining trailing edges of dead wood inhabiting bryophytes.4. Synthesis. Differences in physiological tolerances obviously play a much greater role in shaping the distributional pattern of bryophyte species with different reproductive systems than previously thought. Evidence suggests that current geographic ranges were primarily determined by physiological tolerances and competitive abilities. Species' relationships with forest connectivity were complex and determined by the combination of reproductive traits with other critical species' properties. Given the different species' relationships with climatic gradients, and the varying species' dispersal and competitive capacities, we expect clear changes in metacommunity composition following climate change and an overall decrease in the diversity of dead wood inhabiting bryophytes in Sweden.
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| 8. |
- Löbel, Swantje, 1978-, et al.
(författare)
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Dispersal and life-history strategies in epiphyte metacommunities : alternative solutions to survival in patchy, dynamic landscapes
- 2009
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 161:3, s. 569-579
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Tidskriftsartikel (refereegranskat)abstract
- Host trees for obligate epiphytes are dynamic patches that emerge, grow and fall, and metacommunity diversity critically depends on efficient dispersal. Even though species that disperse by large asexual diaspores are strongly dispersal-limited, asexual dispersal is common. The stronger dispersal limitation of asexually reproducing species compared to species reproducing sexually via small spores may be compensated by higher growth rates, lower sensitivity to habitat conditions, higher competitive ability or younger reproductive age. We compared growth and reproduction of different groups of epiphytic bryophytes with contrasting dispersal (asexual vs sexual) and life-history strategies (colonists, short- and long-lived shuttle species, perennial stayers) in an old-growth forest stand in the boreo-nemoral region in Eastern Sweden. No differences were seen in relative growth rates between asexual and sexual species. Long-lived shuttles had lower growth rates than colonists and perennial stayers. Most groups grew best at intermediate bark pH. Interactions with other epiphytes had a small, often positive effect on growth. Neither differences in sensitivity of growth to habitat conditions nor differences in competitive abilities among species groups were found. Habitat conditions, however, influenced the production of sporophytes, but not of asexual diaspores. Presence of sporophytes negatively affected growth, whereas presence of asexual diaspores did not. Sexual species had to reach a certain colony size before starting to reproduce, whereas no such treshold existed for asexual reproduction. The results indicate that the epiphyte metacommunity is structured by two main trade-offs: dispersal distance vs reproductive age, and dispersal distance vs sensitivity to habitat quality. There seems to be a trade-off between growth and sexual reproduction, but not asexual. Trade-offs in species traits may be shaped by conflicting selection pressures imposed by habitat turnover and connectivity rather than by species interactions.
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| 9. |
- Löbel, Swantje, et al.
(författare)
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Dry grassland communities on southern Öland: phytosociology, ecology, and diversity
- 2008
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Ingår i: Acta Phytogeographica Suecica. - : Wiley. - 0084-5914. ; 88, s. 13-31
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Tidskriftsartikel (refereegranskat)abstract
- We studied dry grassland vegetation on southern Öland, both within and outside the Great Alvar, using the Braun-Blanquet approach. We were able to distinguish 15 associations or equivalent units belonging to three major syntaxa. Dry grasslands on sandy soils (class Koelerio-Corynephoretea; subclass Koelerio-Corynephorenea) occurred along the east and west coasts. Weathered rock and outcrop communities (class Koelerio-Corynephoretea; subclass Sedo-Scleranthenea) inhabited shallow skeletal soils, mainly on the Great Alvar. Semi-dry basiphilous grasslands of the class Festuco-Brometea occurred on moraine soils, which were the least extreme in terms of soil moisture and nutrient availability. Whereas the first category comprises impoverished variants of widely distributed syntaxa, all Sedo-Scleranthenea and Festuco-Brometea communities lack direct counterparts in central Europe. The alvar communities proved to be floristically well separated from the others. Species density on 4 m2 was highest in the Sedo-Scleranthenea (that of the Gypsophilo fastigiatae-Globularietum vulgaris with 80 taxa being one of the highest known), intermediate in the Festuco-Brometea, and lowest in the Koelerio-Corynephorenea. Harsh and variable conditions, small plant sizes, and a large local species pool are considered possible causes.
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| 10. |
- Löbel, Swantje, et al.
(författare)
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Epiphytic bryophytes near forest edges and on retention trees : reduced growth and reproduction especially in old-growth-forest indicator species
- 2012
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 49:6, s. 1334-1343
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Tidskriftsartikel (refereegranskat)abstract
- Epiphytes are an important component in many forest ecosystems. The proportion of threatened epiphyte species is high, and the impact of clearcuts on key demographic processes via edge-influence is still poorly understood. There are few studies on epiphyte growth, and even less is known about how reproduction is affected by proximity to forest edges. For retention trees, demographic studies are even scarcer.Based on the results from a 6-month transplant experiment and a 3-year study of natural colonies, we modelled growth and reproduction of epiphytic bryophytes used as indicators of old-growth forests and widespread epiphytes in relation to distance from the forest edge. We also modelled growth and reproduction on retention trees within the clearcut. Species responses were linked to variation in canopy openness.Unlike the widespread species, the old-growth-forest indicators grew exponentially with distance from the edge, and this response was more pronounced at the south-east than north-west forest edge. In one red-listed species, reproduction was thoroughly inhibited near the edge, whereas the reproductive rate of the widespread species tended to increase. However, the widespread species also showed reduced shoot lengths on the retention trees.Reduced growth and inhibited reproduction of sensitive epiphytes near edges decrease the number of dispersing diaspores and may, in combination with lower local connectivity and increased tree fall rates close to edges, increase the risk of metapopulation extinction.Synthesis and applications. Two general management implications for boreal forests are drawn. First, retention trees may not have the capacity to act as a ‘lifeboat’ for epiphytic bryophytes and support their populations during the regeneration phase. Second, the creation of buffer zones is a useful conservation strategy for bryophytes. The exact width of zones depends on the forest structure and should be orientated in relation to the requirements of the most sensitive species. For the rather dense experimental forest, a width of at least 30 m was required for the south-facing buffer, whereas for the north-facing buffer 10 m was sufficient.
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