Scale decisions can reverse conclusions on community assembly processes

Münkemüller, Tamara; Gallien, Laure; Lavergne, Sébastien; Renaud, Julien; Roquet, Cristina; Abdulhak, Sylvain; Dullinger, Stefan; Garraud, Luc; Guisan, Antoine; Lenoir, Jonathan; Svenning, Jens‐Christian; Es, Jérémie Van; Vittoz, Pascal; Willner, Wolfgang; Wohlgemuth, Thomas; Zimmermann, Niklaus E.; Thuiller, Wilfried

doi:10.1111/geb.12137

Cited by 65 publications

(68 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Indeed, if environmental heterogeneity is too high, fine‐scale environmental filtering processes may lead to differences in co‐occurrence and co‐abundance patterns similar to those expected from facilitation (i.e., if the niche of the species B is nested within the one of A and A's abundance is generally higher than that of B). We note that such assumption about environmental homogeneity is similarly made (although not always explicitly) in most analyses of community functional similarity patterns (e.g., when inferring environmental filtering and competition processes; Münkemüller et al., 2014; Willis et al., 2010). Additionally, our estimation of facilitation intensity relies on the assumption that an increase in relative cover of species is associated with an increase in its fitness.…”

Section: Methodsmentioning

confidence: 99%

Frequency and intensity of facilitation reveal opposing patterns along a stress gradient

Gallien

Zurell

Zimmermann

2018

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

Disentangling the different processes structuring ecological communities is a long‐standing challenge. In species‐rich ecosystems, most emphasis has so far been given to environmental filtering and competition processes, while facilitative interactions between species remain insufficiently studied. Here, we propose an analysis framework that not only allows for identifying pairs of facilitating and facilitated species, but also estimates the strength of facilitation and its variation along environmental gradients. Our framework combines the analysis of both co‐occurrence and co‐abundance patterns using a moving window approach along environmental gradients to control for potentially confounding effects of environmental filtering in the co‐abundance analysis. We first validate our new approach against community assembly simulations, and exemplify its potential on a large 1,134 plant community plots dataset. Our results generally show that facilitation intensity was strongest under cold stress, whereas the proportion of facilitating and facilitated species was higher under drought stress. Moreover, the functional distance between individual facilitated species and their facilitating species significantly changed along the temperature–moisture gradient, and seemed to influence facilitation intensity, although no general positive or general negative trend was discernible among species. The main advantages of our robust framework are as follows: It enables detecting facilitating and facilitated species in species‐rich systems, and it allows identifying the directionality and intensity of facilitation in species pairs as well as its variation across long environmental gradients. It thus opens numerous opportunities for incorporating functional (and phylogenetic) information in the analysis of facilitation patterns. Our case study indicated high complexity in facilitative interactions across the stress gradient and revealed new evidence that facilitation, similarly to competition, can operate between functionally similar and dissimilar species. Extending the analyses to other taxa and ecosystems will foster our understanding how complex interspecific interactions promote biodiversity.

show abstract

Section: Methodsmentioning

confidence: 99%

Frequency and intensity of facilitation reveal opposing patterns along a stress gradient

Gallien

Zurell

Zimmermann

2018

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

show abstract

“…Diversity within each summit community (α-diversity) was assessed for all Spermatophyta and separately within five orders with the greatest species-richness to account for taxonomic scale (Munkemüller et al ., 2014) by calculating two widely used measures of phylogenetic distance: the mean nearest taxon distance (MNTD) and the mean pairwise distance (MPD), to capture more recent and phylogeny-wide patterns, respectively (Webb et al ., 2002). Beta phylogenetic diversity between all pairs of summits was also estimated using the PhyloSor index (as in Leprieur et al .…”

Section: Methodsmentioning

confidence: 99%

Riders in the sky (islands): Using a mega‐phylogenetic approach to understand plant species distribution and coexistence at the altitudinal limits of angiosperm plant life

Marx

Dentant²,

Renaud

et al. 2017

Journal of Biogeography

Self Cite

View full text Add to dashboard Cite

Aim Plants occurring on high-alpine summits are generally expected to persist due to adaptations to extreme selective forces caused by the harshest climates where angiosperm life is known to thrive. We assessed the relative effects of this strong environmental filter and of other historical and stochastic factors driving plant community structure in very high-alpine conditions (up to 4,000m). Location European Alps, Écrins National Park, France. Methods Using species occurrence data collected from floristic surveys on 15 summits (2,791 m – 4,102 m a.s.l.) throughout the Écrins range, along with existing molecular sequence data obtained from GenBank, we used a mega-phylogenetic approach to evaluate the phylogenetic structure of high-alpine plant species assemblages. We used three nested species pools and two null models to address the importance of species-specific and species-neutral processes for driving coexistence. Results Compared to the entire species pool of the study region, alpine summits exhibited a strong signal of phylogenetic clustering. Restricting statistical sampling to environmentally and historically defined species pools reduced the significance of this pattern. However, we could not reject a model that explicitly incorporates neutral colonization and local extinction in shaping community structure for dominant plant orders. Between summits, phylogenetic turnover was generally lower than expected. Environmental drivers did not explain overall phylogenetic patterns, but we found significant geographic and climatic structure in phylogenetic diversity at finer taxonomic scales. Main conclusions Although we found evidence for strong phylogenetic clustering within alpine summits, we were not able to reject models of species-neutral processes to explain patterns of floristic diversity. Our results suggest that plant community structure in high-alpine regions can also be shaped by neutral processes, and not through the sole action of environmental selection as traditionally assumed for harsh and stressful environments.

show abstract

“…The sampling strategy for a given study may focus on the most species-rich clades (e.g., Kellar et al, 2015), the taxa that are either most ecologically representative or ecologically dominant (e.g., Araya et al, 2012), or the taxa that are relevant to a specific research question (e.g., Cavender-Bares et al, 2004;Mishler et al, 2014;Münkemüller et al, 2014). The sampling strategy for a given study may focus on the most species-rich clades (e.g., Kellar et al, 2015), the taxa that are either most ecologically representative or ecologically dominant (e.g., Araya et al, 2012), or the taxa that are relevant to a specific research question (e.g., Cavender-Bares et al, 2004;Mishler et al, 2014;Münkemüller et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…vary depending on the question, but is crucial (e.g.,Cavender-Bares et al, 2004;Cavender-Bares, Keen, & Miles, 2006;Münkemüller et al, 2014). Thus, conclusions about the ecological processes taking place in the community would only be applicable to each clade and could not be generalized to the overall community (also suggested byMünkemüller et al, 2014). With the exception of the complete dataset, each of these clades had similar species richness in this community.…”

mentioning

confidence: 99%

Effects of taxon sampling and tree reconstruction methods on phylodiversity metrics

Jantzen

Whitten

Neubig

et al. 2019

Ecology and Evolution

View full text Add to dashboard Cite

The amount and patterns of phylodiversity in a community are often used to draw inferences about the local and historical factors affecting community assembly and can be used to prioritize communities and locations for conservation. Because measures of phylodiversity are based on the topology and branch lengths of phylogenetic trees, which are affected by the number and diversity of taxa in the tree, these analyses may be sensitive to changes in taxon sampling and tree reconstruction methods. To investigate the effects of taxon sampling and tree reconstruction methods on measures of phylodiversity, we investigated the community phylogenetics of the Ordway‐Swisher Biological Station (Florida), which is home to over 600 species of vascular plants. We studied the effects of (a) the number of taxa included in the regional phylogeny; (b) random versus targeted sampling of species to assemble the regional species pool; (c) including only species from specific clades rather than broad sampling; (d) using trees reconstructed directly for the taxa under study compared to trees pruned from a larger reconstructed tree; and (e) using phylograms compared to chronograms. We found that including more taxa in a study increases the likelihood of observing significantly nonrandom phylogenetic patterns. However, there were no consistent trends in the phylodiversity patterns based on random taxon sampling compared to targeted sampling, or within individual clades compared to the complete dataset. Using pruned and reconstructed phylogenies resulted in similar patterns of phylodiversity, while chronograms in some cases led to significantly different results from phylograms. The methods commonly used in community phylogenetic studies can significantly impact the results, potentially influencing both inferences of community assembly and conservation decisions. We highlight the need for both careful selection of methods in community phylogenetic studies and appropriate interpretation of results, depending on the specific questions to be addressed.

show abstract

Scale decisions can reverse conclusions on community assembly processes

Cited by 65 publications

References 38 publications

Frequency and intensity of facilitation reveal opposing patterns along a stress gradient

Frequency and intensity of facilitation reveal opposing patterns along a stress gradient

Riders in the sky (islands): Using a mega‐phylogenetic approach to understand plant species distribution and coexistence at the altitudinal limits of angiosperm plant life

Effects of taxon sampling and tree reconstruction methods on phylodiversity metrics

Contact Info

Product

Resources

About