Measures Of Species Turnover Research Articles

Maximizing the monitoring of diversity for management activities: Additive partitioning of plant species diversity across a frequently burned ecosystem

Monitoring understory plant diversity is important, allowing managers to track current diversity status and trends both spatially and temporally at a landscape-scale. Improving precision in quantifying patterns in understory plant diversity improves efficiency in monitoring design and more accurate measures of success of management intervention over time. Patterns of species diversity are dependent upon the scale in which they are examined – an increase in small-scale diversity across a gradient can convert to a decrease in large-scale diversity across that same gradient. Using two extensive datasets including both mined historical data and supplemental experimental data, we performed an additive partitioning of plant diversity to elucidate the hierarchical spatial patterns of understory plant species richness, and independent measures of alpha and beta diversity in the species-rich longleaf pine ecosystem at Eglin Air Force Base in northwestern FL, USA. This analysis allowed us to identify the spatial scale that most effectively captures plant diversity to inform monitoring efforts by using measures of species turnover, specifically beta diversity. We found that while species richness and alpha diversity increased with spatial scale, beta diversity began to reach an asymptote at smaller (1 m2) scales. Furthermore, we found the sampling effort at this 1 m2 scale required as few as 60 plots to effectively estimate plant diversity within management blocks. While our results are attributable to Eglin AFB specifically, these scaling analyses can help to streamline monitoring efforts in other ecosystems that seek to elucidate the individual contributions of diversity components.

Combining the effects of biological invasion and climate change into systematic conservation planning for the Atlantic Forest

Biological invasions and climate changes are the major causes of changes in biodiversity, which reduce, shift, and extinguish species ranges. While climate changes have been widely used in systematic conservation planning (SCP), biological invasions are rarely considered. Here, we combine the effects of climate changes and Artocarpus heterophyllus Lam. (Moraceae) invasion on the SCP for endemic aromatic fruit tree species from the Atlantic Forest (EFAF). We tested the effect of invasion on SCP measures of species turnover, biotic stability, and irreplaceability. Ecological niche models were used to establish species environmental suitability for the preindustrial period for both invasive species and EFAF and to forecast to the end of the century (2080–2100). We calculated the niche overlap between the invasive species and EFAF and tested the overlap significance using a null model. We tested the biological invasion effect on the results using results with no species invasion correction. The niche overlap between A. heterophyllus and EFAF was significant for 50% of species in the preindustrial period and for 33% in the future. The spatial patterns of species turnover, biotic stability, and irreplaceability had significant effects on biological invasion changing the spatial pattern in both shape and magnitude, which can misplace and overvalue conservation priorities. We showed that the disregard of biological invasion on SCP can cause negative effects on SCP under climate change. We strongly recommend accounting for biological invasion in the evaluation of SCP.

Multi‐site generalised dissimilarity modelling: using zeta diversity to differentiate drivers of turnover in rare and widespread species

SummaryGeneralised dissimilarity modelling (GDM) applies pairwise beta diversity as a measure of species turnover with the purpose of explaining changes in species composition under changing environments or along environmental gradients. Beta diversity only captures turnover across pairs of sites and, therefore, disproportionately represents turnover in rare species across communities. By contrast, zeta diversity, the average number of shared species across multiple sites, captures the full spectrum of rare, intermediate and widespread species as they contribute differently to compositional turnover.We show how integrating zeta diversity intoGDMs (which we term multi‐site generalised dissimilarity modelling,MS‐GDM), provides a more information rich approach to modelling how communities respond to environmental variation and change. We demonstrate the value of including zeta diversity in biodiversity assessment and modelling using BirdLife Australia Atlas data. Zeta diversity values for different numbers of sites (the order of zeta) are regressed against environmental differences and distance using two kinds of regressions: shape constrained additive models and a combination of I‐splines and generalised linear models.ApplyingMS‐GDMto different orders of zeta revealed shifts in the importance of environmental variables in explaining species turnover, varying with the order of zeta and thus with the level of co‐occurrence of the species and, by extension, their commonness and rarity. In particular, precipitation gradients emerged as drivers in the turnover of rare species, whereas temperature gradients were more important drivers of turnover in widespread species.Appreciation of the factors that drive compositional turnover across multiple sites is necessary for accommodating the full spectrum of compositional turnover across rare to common species. This extends beyond understanding drivers for pairwise beta diversity only.MS‐GDMprovides a valuable addition to the toolkit ofGDM, with further potential for survey gap analysis and prediction of species composition in unsampled sites.

A guide through a family of phylogenetic dissimilarity measures among sites

Ecological studies have now gone beyond measures of species turnover towards measures of phylogenetic and functional dissimilarity. This change of perspective has a main objective: disentangling the processes that drive species distributions from local to broad scales. A fundamental difference between phylogenetic and functional analyses is that phylogeny is intrinsically dependent on a tree‐like structure whereas functional data can, most of time, only be forced to adhere a tree structure, not without some loss of information. When the branches of a phylogenetic tree have lengths, then each evolutionary unit on these branches can be considered as a basic entity on which dissimilarities among sites should be measured. Several of the recent measures of phylogenetic dissimilarities among sites thus are traditional dissimilarity indices where species are replaced by evolutionary units. The resulting indices were named PD‐dissimilarity indices, in reference to early work on the phylogenetic diversity (PD) measure. Here I review and compare indices and ordination approaches that, although first developed to analyse the differences in the species compositions of sites, can be adapted to describe PD‐dissimilarities among sites. Using simulations of species distributions along environmental gradients, I compare indices, associated with permutation tests and null models, in their ability to reveal existing phylogenetic patterns along the gradients. As an illustration, I show that the amount of bat PD‐dissimilarities along a disturbance gradient in Selva Lacandona of Chiapas, Mexico is dependent on whether species' abundance is considered, and on the PD‐dissimilarity index used. Overall, the family of PD‐dissimilarity indices has a critical potential for future analyses of phylogenetic diversity as it benefits from decades of research on the measure of species dissimilarity. I provide clues to help to choose among many potential indices, identifying which indices satisfy minimal basic properties, and analysing their sensitivity to abundance, size, diversity and joint absences.

Biotic homogenization of urban floras by alien species: the role of species turnover and richness differences

AbstractQuestionThe spread of alien species has been changing the diversity of plant communities all over the world, perhaps most notably in urban habitats. It has been shown that alien species with different residence times have different impacts on the β‐diversity of urban plant communities: archaeophytes tend to contribute to homogenization, while neophytes tend to increase differentiation among sites. However, it has not been determined whether these processes result from changes in species turnover or from differences in species richness. Here, we use an additive partitioning framework to disentangle the contribution of species turnover and richness difference to β‐diversity patterns in invaded urban plant communities.LocationThirty‐two cities in ten countries of Central Europe and Benelux.MethodsWe analysed the effects of alien species on β‐diversity of urban plant communities separately for archaeophytes and neophytes to assess whether the observed patterns differ between these two groups of species with different residence times in the invaded region. We used additive as well as non‐additive measures of species turnover and richness difference. For this purpose, we proposed a new index that complements the recently proposed Podani‐Schmera index of richness difference.ResultsWe confirmed the results of earlier studies that neophytes tend to differentiate the urban plant communities, while archaeophytes tend to homogenize, although in some specific habitats they can also contribute to differentiation. The observed changes in β‐diversity were related to the turnover component of β‐diversity in most cases, especially for neophytes. In contrast, the richness difference component was not significantly different between neophytes and native species. The trends for archaeophytes were less consistent, but in most habitats their turnover and richness difference were not significantly different from native species.ConclusionsChanges in β‐diversity of urban plant communities induced by the establishment of alien species reflect mainly species turnover, whereas the richness difference component has small effects restricted to certain habitats only.

The need for richness‐independent measures of turnover when delineating biogeographical regions

AbstractDelineating biogeographical regions is one of the primary steps when analysing biogeographical patterns. In their proposed quantitative framework, Kreft & Jetz (2010, Journal of Biogeography, 37, 2029–2053) recommended the use of the βsim index to delineate biogeographical regions because this turnover measure is weakly affected by differences in species richness between localities. A recent study by Carvalho et al. (2012, Global Ecology and Biogeography, 21, 760–771) critiziced the use of βsim in ecological and biogeographical studies, and proposed the β‐3 index. Here we used simple numerical examples and an empirical case study (European freshwater fishes) to highlight potential pitfalls associated with the use of β‐3 for bioregionalization. We show that β‐3 is not a richness‐independent measure of species turnover. We also show that this index violates the ‘complementarity’ property, namely that localities without species in common have the largest dissimilarity, which is an essential prerequisite for beta diversity studies.

Current measures for distance decay in similarity of species composition are influenced by study extent and grain size

ABSTRACTAim The relationship between geographic distance and similarity in species composition is regularly used as a measure of species turnover and beta diversity. Distance–decay analyses are applied, cited and compared despite the variable extent, and different grain sizes of records (e.g. plots, islands, states) are regularly used within such analyses. Currently, differences among distance–decay relationships that cover different grain sizes and extents are attributed to ecological processes that are suspected to operate differently over varying extents and grain sizes. We assess whether the implicit assumption that the distance–decay relation is independent of grain size and study extent is valid, or whether sampling design could be the underlying cause for observed differences.Location An artificial one‐dimensional ‘landscape’.Methods The distance–decay relationship was quantified in simulated communities. Grain and study extent were varied systematically. In each sampled data set the linear relation of Simpson and Sørensen similarity to geographic distance (on both log‐transformed and original scales) between 100 even‐sized equidistant plots was assessed using linear regression and generalized linear regression with a log‐link function. Regressions were applied either including or removing zero similarities from the data.Results Both the slope (measuring turnover) and the goodness of fit measure r2 (quantifying the influence of space on species composition) of the distance–decay relationship were strongly influenced by grain and study extent. Approaches that are able to cope with zero similarity values of large distance comparisons were less dependent on grain and extent.Main conclusions Reported differences between landscapes detected by current distance–decay measures cannot be explicitly traced back to ecological scale‐specific processes. Instead, they can largely be attributed to sampling design and are highly sensitive to grain size and study extent. More appropriate approaches for the study of distance–decay and the understanding of scale‐specific processes are required.

β-diversity as a measure of species turnover along the salinity gradient in the Baltic Sea, and its ­consistency with the Venice System

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 436:101-118 (2011) - DOI: https://doi.org/10.3354/meps09219 β-diversity as a measure of species turnover along the salinity gradient in the Baltic Sea, and its ­consistency with the Venice System S. Bleich1,*, M. Powilleit1, T. Seifert2, G. Graf1 1Institute of Biological Sciences-Marine Biology, University of Rostock, Albert Einstein Strasse 3, 18059 Rostock, Germany 2Leibniz Institute for Baltic Sea Research, Warnemünde, Seestrasse 15, 18119 Rostock, Germany *Email: steffen.bleich@googlemail.com ABSTRACT: Transition zones between marine and freshwater environments are characterized by a pronounced salinity gradient and concomitant variation in invertebrate species richness. Here we use the β-diversity concept to depict the species turnover of macrobenthic species along the salinity gradient of the Baltic Sea with salinities ranging from 34 in the transition zone to the North Sea to less than 5 in the Bothnian Sea. Based on 250 data sets from 72 locations that were grouped into 2 habitats defined according to their depths and sediment types (shallower: 15 to 19 m, fine to medium sand; deeper: 20 to 35 m, silt to silty sand), we calculated the ­Jaccard dissimilarity index (β1–J) as a measure of species turnover. To keep the focus on the salinity gradient, sediment characteristics and the time period covered by the data sets (spring and summer 1995 to 2005) were predefined. The mean hydrographic parameters, including temperatures, salinities and dissolved oxygen (DO) concentrations of the sample locations were derived from model ­calculations based on data gathered over a 3 yr period before sampling. At the deeper stations, the total number of macrofaunal species was 255, while at the shallower ones, 172 taxa were found. Statistical analyses revealed salinity to be the main structuring factor for macrobenthic species turnover. High correlations between the β1–J index and mean salinities in both habitats (Spearman’s rank correlation coefficient ρ = 0.88 in shallower and ρ = 0.86 in deeper areas) confirmed these findings. β-diversity values with median β1–J varied between 51 and 65% within the salinity classes eu-, poly-, α-meso- and β-mesohaline, while values of 75 to 100% characterized between-group comparisons. Furthermore, these high β-diversity values depict a discontinuous change in the communities and are found at salinities of around 10, 18, and 30, which ties in fairly well with the existing salinity boundaries postulated by the Venice System. KEY WORDS: Species turnover · β-diversity · Salinity gradient · Macrofauna · Venice System · Baltic Sea Full text in pdf format PreviousNextCite this article as: Bleich S, Powilleit M, Seifert T, Graf G (2011) β-diversity as a measure of species turnover along the salinity gradient in the Baltic Sea, and its ­consistency with the Venice System. Mar Ecol Prog Ser 436:101-118. https://doi.org/10.3354/meps09219 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 436. Online publication date: August 31, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.