Comparing Diversity Indices Based on Counts Weighted by Biomass or Other Importance Values

Lyons, N. I.

doi:10.1086/283836

Cited by 20 publications

(9 citation statements)

References 11 publications

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“…Plot-scale diversity (H′) was calculated as: H′= −∑ S i¼1 P i lnP i , where S is the plot-scale species richness and P i is aboveground biomass of species i divided by total aboveground biomass of all plant species in the four sampled patches in a plot. We used biomass rather than the number of individuals to calculate H′ to account for differences in the size of species in a community (Lyons 1981). Patch-scale species richness was determined by averaging the species number over the four sampled patches per plot (or in the case of heterogeneous soil treatments, averaged over each of the two patch types).…”

Section: Discussionmentioning

confidence: 99%

Soil heterogeneity and plant species diversity in experimental grassland communities: contrasting effects of soil nutrients and pH at different spatial scales

2019

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Background and aims Current knowledge of soil heterogeneity-diversity relationships (HDR) is largely based on studies manipulating single factor, but the advancements in HDR may require a comprehensive experiment incorporating multiple factors. Methods We conducted a three-year field experiment in which a seed mixture of 16 common grassland species was sown in plots with heterogeneous soils consisting of small (10 cm × 10 cm) or large patches (30 cm × 30 cm) of low and high nutrients or low and high pH, and homogeneous soils with an even mixture of low and high nutrient/pH soils. Soil nutrients and pH were manipulated in separate treatments. We determined plant species richness and diversity at two focal scales (40 cm × 40 cm plotscale and 10 cm × 10 cm patch-scale). Results Plot-scale richness and diversity were not influenced by soil heterogeneity, but patch-scale richness was lower in plots with heterogeneous nutrients than in plots where nutrients were distributed homogeneously. There was no difference between the two heterogeneous nutrient soils with different grain sizes. Patch-scale diversity was higher in heterogeneous pH soils of large patch size than in heterogeneous pH soils of small patch size or the homogeneous pH soil at the final harvest. Species richness and diversity quantified at both plot and patch scales declined in all soils over time. Conclusions The influence of soil heterogeneity on plant species diversity depends on whether the soil varies in nutrients or pH, and on the temporalspatial scale at which species diversity and soil heterogeneity are measured. These results indicate that soil heterogeneity has the potential to promote plant coexistence and future HDR studies should consider multiple soil factors at various temporalspatial scales.

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Section: Discussionmentioning

confidence: 99%

Soil heterogeneity and plant species diversity in experimental grassland communities: contrasting effects of soil nutrients and pH at different spatial scales

2019

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“…For invertebrates, we used an ANOVA to evaluate effects of treatment, month, and their interaction on mass for November–February 2006–2009, as previously described. We calculated Shannon's index of diversity using mass by Order for each treatment plot and month and computed averages across years (Hair 1980, Lyons 1981, Gray et al 1999, Zar 2009).…”

Section: Methodsmentioning

confidence: 99%

Winter waterbird and food dynamics in autumn‐managed moist‐soil wetlands in the Mississippi Alluvial Valley

Hagy

Kaminski

2012

Wildlife Society Bulletin

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Managed moist-soil wetlands are important habitats for waterfowl and other waterbirds in the Mississippi Alluvial Valley (MAV) and elsewhere in North America. These wetlands often contain abundant food resources, but they also contain tall and dense (i.e., robust) vegetation that may constrain use and foraging by waterbirds. During winters 2006-2009, we estimated densities of waterbirds, seeds and tubers, and aquatic invertebrates following autumn, preflooding treatments of disking, mowing, and no manipulation (control) of robust vegetation in 26 moist-soil wetlands in and near the MAV. In late autumn, seed and tuber dry mass was greater in control (x ¼ 750.7 kg/ha) and mowed (x ¼ 709.7 kg/ha) than disked plots (x ¼ 509.8 kg/ha). Dabbling ducks (Anatini) accounted for 92% of all waterbirds observed and were 2-3 times more abundant in mowed and disked than control plots during winter. Invertebrates comprised <1% (dry mass) of potential waterbird foods, but were greatest in control plots throughout winter. In mid-and late winter, residual seed and tuber masses were similar among mowed, disked, and control plots within study sites (approx. 260 kg/ha), despite different waterbird use. We recommend 1) active management of moistsoil wetlands, including partial autumn mowing of robust vegetation to increase use by waterbirds; 2) that conservation planners consider increasing foraging thresholds (e.g., giving-up density) in carrying-capacity models for moist-soil wetlands; and 3) additional experiments to describe foraging thresholds in moist-soil and other wetlands

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“…Species with higher proportions in a community are considered to characterize the community better than species with lower proportions. For instance, for organisms with very different biomass, measuring diversity using biomass might be more relevant than using the number of individuals (e.g., [25]). When the objective is to compare the composition of communities, species with high and unequal proportions over all communities will contribute more to the definition of the differences among communities than species with low, even if unequal, proportions in all communities.…”

Section: Methodsmentioning

confidence: 99%

A New Technique for Analysing Interacting Factors Affecting Biodiversity Patterns: Crossed-DPCoA

Pavoine

Blondel²,

Dufour

et al. 2013

PLoS ONE

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We developed an approach for analysing the effects of two crossed factors A and B on the functional, taxonomic or phylogenetic composition of communities. The methodology, known as crossed-DPCoA, defines a space where species, communities and the levels of the two factors are organised as a set of points. In this space, the Euclidean distance between two species-specific points is a measure of the (functional, taxonomic or phylogenetic) dissimilarity. The communities are positioned at the centroid of their constitutive species; and the levels of two factors at the centroid of the communities associated with them. We develop two versions for crossed-DPCoA, the first one moves the levels of factor B to the centre of the space and analyses the axes of highest variance in the coordinates of the levels of factor A. It is related to previous ordination approaches such as partial canonical correspondence analysis and partial non-symmetrical correspondence analysis. The second version projects all points on the orthogonal complement of the space generated by the principal axes of factor B. This second version should be preferred when there is an a priori suspicion that factor A and B are associated. We apply the two versions of crossed-DPCoA to analyse the phylogenetic composition of Central European and Mediterranean bird communities. Applying crossed-DPCoA on bird communities supports the hypothesis that allopatric speciation processes during the Quaternary occurred in open and patchily distributed landscapes, while the lack of geographic barriers to dispersal among forest habitats may explain the homogeneity of forest bird communities over the whole western Palaearctic. Generalizing several ordination analyses commonly used in ecology, crossed-DPCoA provides an approach for analysing the effects of crossed factors on functional, taxonomic and phylogenetic diversity, environmental and geographic structure of species niches, and more broadly the role of genetics on population structures.

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Comparing Diversity Indices Based on Counts Weighted by Biomass or Other Importance Values

Cited by 20 publications

References 11 publications

Soil heterogeneity and plant species diversity in experimental grassland communities: contrasting effects of soil nutrients and pH at different spatial scales

Soil heterogeneity and plant species diversity in experimental grassland communities: contrasting effects of soil nutrients and pH at different spatial scales

Winter waterbird and food dynamics in autumn‐managed moist‐soil wetlands in the Mississippi Alluvial Valley

A New Technique for Analysing Interacting Factors Affecting Biodiversity Patterns: Crossed-DPCoA

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