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Alpha and beta diversity of plants and animals along a tropical land-use gradient

Albrecht-von-Haller-Institute of Plant Sciences, University of Göttingen, 37073 Göttingen, Germany.
Ecological Applications (Impact Factor: 4.13). 12/2009; 19(8):2142-56. DOI: 10.1890/08-1074.1
Source: PubMed

ABSTRACT Assessing the overall biological diversity of tropical rain forests is a seemingly insurmountable task for ecologists. Therefore, researchers frequently sample selected taxa that they believe reflect general biodiversity patterns. Usually, these studies focus on the congruence of alpha diversity (the number of species found per sampling unit) between taxa rather than on beta diversity (turnover of species assemblages between sampling units). Such approaches ignore the potential role of habitat heterogeneity that, depending on the taxonomic group considered, can greatly enhance beta diversity at local and landscape scales. We compared alpha and beta diversity of four plant groups (trees, lianas, terrestrial herbs, epiphytic liverworts) and eight animal groups (birds, butterflies, lower canopy ants, lower canopy beetles, dung beetles, bees, wasps, and the parasitoids of the latter two) at 15 sites in Sulawesi, Indonesia, that represented natural rain forest and three types of cacao agroforests differing in management intensity. In total, we recorded 863 species. Patterns of species richness per study site varied strongly between taxonomic groups. Only 13-17% of the variance in species richness of one taxonomic group could be predicted from the species richness of another, and on average 12-18% of the variance of beta diversity of a given group was predicted by that in other groups, although some taxon pairs had higher values (up to 76% for wasps and their parasitoids). The degree of congruence of patterns of alpha diversity was not influenced by sampling completeness, whereas the indicator value for beta diversity improved when using a similarity index that accounts for incomplete sampling. The indication potential of alpha diversity for beta diversity and vice versa was limited within taxa (7-20%) and virtually nil between them (0-4%). We conclude that different taxa can have largely independent patterns of alpha diversity and that patterns of beta diversity can be more congruent. Thus, conservation plans on a landscape scale need to put more emphasis on the high heterogeneity of agroforests and the overarching role of beta diversity shaping overall diversity patterns.

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    • "Species turnover can alter the taxonomic or functional distinctness of communities without changing the overall number of species. For example , if a few closely related species are replaced by species that have no close relatives in the community (see also Kessler et al. 2009) or if functionally similar species are replaced by species with one or more exceptional traits (Mayfield et al. 2010). All analyzed arthropod taxa were characterized by a higher functional distinctness in taxonomically more distinct communities if analyzed independent of land-use type or intensity. "
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    ABSTRACT: Land-use change is a major driver of the global loss of biodiversity, but it is unclear to what extent this also results in a loss of ecological traits. Therefore, a better understanding of how land-use change affects ecological traits is crucial for efforts to sustain functional diversity. To this end we tested whether higher species richness or taxonomic distinctness generally leads to increased functional distinctness and whether intensive land use leads to functionally more narrow arthropod communities. We compiled species composition and trait data for 350 species of terrestrial arthropods (Araneae, Carabidae and Heteroptera) in different land-use types (forests, grasslands and arable fields) of low and high land-use intensity. We calculated the average functional and taxonomic distinctness and the rarified trait richness for each community. These measures reflect the range of traits, taxonomic relatedness and number of traits that are observed in local communities. Average functional distinctness only increased significantly with species richness in Carabidae communities. Functional distinctness increased significantly with taxonomic distinctness in communities of all analyzed taxa suggesting a high functional redundancy of taxonomically closely related species. Araneae and Heteroptera communities had the expected lower functional distinctness at sites with higher land-use intensity. More frequently disturbed land-use types such as managed grasslands or arable fields were characterized by species with smaller body sizes and higher dispersal abilities and communities with lower functional distinctness or trait richness. Simple recommendations about the conservation of functional distinctness of arthropod communities in the face of future land-use intensification and species loss are not possible. Our study shows that these relationships depend on the studied taxa and land-use type. However, for some arthropod groups functional distinctness is threatened by intensification and conversion from less to more frequently disturbed land-uses.
    Ecography 01/2015; DOI:10.1111/ecog.01141 · 4.21 Impact Factor
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    • "This is partly explainable by the fact that a-diversity does not take into account information on taxonomic composition, in opposite to bdiversity . It is expected, for instance, that in equally benign and productive environments, b-diversity could change more strongly across a range of environmental conditions than local a-diversity (Kessler et al. 2009). For fish and macroinvertebrates, local a-diversity appeared smaller than expected by chance, indicating that individuals of the same species tended to be locally aggregated. "
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    ABSTRACT: Although the important contribution of β-diversity to regional (γ) diversity is increasingly recognised, our understanding of how the spatial scaling of β-diversity differs among taxonomic groups is still limited, especially in dynamic lotic ecosystems. In this study, we assessed the difference in the partitioning of diversity at nested spatial scales, from reach to catchment, among riparian birds, fish and benthic macroinvertebrates in Mediterranean river systems. Fish and macroinvertebrates showed similar scaling patterns, with β-diversity always larger than expected by a random distribution of individuals at all spatial scales (among reaches, rivers and catchments), and local (α) diversity always lower than expected. Conversely, β-diversity of riparian birds appeared larger than expected only at the largest scale (among catchments), while local diversity did not differ from random expectation. For birds, however, results partly depended on the weighting of abundant and rare species. Although the relative contribution of β to γ-diversity did not differ substantially among groups (with multiplicative β representing five to six distinct communities), its deviation from random expectations showed marked differences indicating that functionally different groups exhibit distinct spatial patterns. This study is among the first to investigate scaling patterns in β-diversity across taxonomic groups with different ecological requirements and dispersal ability, and provides a holistic picture of riverine biodiversity. From a conservation perspective, the results suggest that, in these river systems, flexible conservation strategies are required in order to protect multiple taxonomic groups.
    Aquatic Sciences 12/2014; 77(3). DOI:10.1007/s00027-014-0390-3 · 2.71 Impact Factor
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    • "C represents the number of species shared by both A and B. An increase in the Sørensen index signifies an increase in the similarity of species assemblages between burnt and unburnt habitats and thus a decrease in beta diversity. As with our alpha-diversity metric, metrics such as the Bray–Curtis dissimilarity index (Kessler et al., 2009) which take into account species abundances could not be calculated given the limited quantitative information that was presented in many studies. We used a hierarchical approach to investigate the effects of fire on alpha and beta diversity (Rosenberg et al., 2000). "
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    ABSTRACT: AimWe conducted a quantitative meta-analysis to investigate the responses of vertebrate diversity to fire, controlling for variables such as fire type, taxon and ecoregion to identify trends across studies and locations.LocationWorld-wide.Methods We calculated indices of the difference in species richness (alpha diversity) and species composition (beta diversity) between burnt and unburnt habitats from studies reporting the species richness and assemblage composition of amphibians, reptiles, birds and mammals. We used a hierarchical approach to investigate the effects of fire on alpha and beta diversity. We tested first for the main effect of fire before investigating the potential influence of fire type (wildfire/prescribed burn), taxon, ecoregion and geographical location (hemisphere/continent).ResultsOne hundred and four studies were evaluated: 56 studies on birds, 26 on mammals, 17 on reptiles and 5 on amphibians. The studies fell into 14 ecoregions, with the three most common being temperate broadleaf and mixed forests, temperate grasslands and savannas and shrublands, and temperate coniferous forest. The effect of fire on species richness and community assemblage composition was strongly influenced by fire type. Prescribed burns significantly increased alpha diversity, whereas wildfires had no overall effect. However, wildfire increased the alpha diversity of temperate coniferous birds in North America. The effects of fire on alpha diversity were stronger in the Northern than the Southern Hemisphere. Turnover in species assemblages (beta diversity) was influenced primarily by fire type. Species assemblages in burnt and unburnt habitats were more similar after prescribed burns and generated lower levels of beta diversity than did wildfires.Main conclusionsThe divergent effects of wildfires and prescribed fires on the alpha and beta diversity of vertebrates and the disparate responses of vertebrate diversity to fires in the Northern and Southern Hemisphere suggest that there is no general response of vertebrate diversity to fire. Our results provide little support for the patch mosaic burn theory or the intermediate disturbance hypothesis to predict post-fire responses of vertebrate diversity.
    06/2014; 23(10). DOI:10.1111/geb.12195
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