Biology subjects

Smithers, B. V.

Publications and source records attributed to Smithers, B. V..

2 recordsLinked to original sources

bioRxiv2026

Temporal stasis in three facets of biodiversity reveals mechanisms of community assembly across elevation gradients

Understanding spatial and temporal variation in community composition is central to protecting and monitoring biodiversity. Similarity in the composition of two communities decreases along spatial and temporal gradients, a relationship known as distance decay. Comparing distance-decay relationships across taxonomic, functional, and bioclimatic facets of diversity provides a means of interrogating niche-based versus neutral influences on community assembly. Furthermore, the context in which these facets yield overlapping or complementary information about global change impacts remains poorly understood. In this study, we examined spatiotemporal distance-decay relationships for taxonomic, functional, and bioclimatic facets of alpine plant diversity leveraging elevation gradients on five peaks in the White Mountains, California, USA, sampled at 3-4 time points between 2007 and 2024. Using multivariate Bayesian beta regression models, we estimated the slopes of elevation distance decay over multiple surveys and across taxonomic, functional and bioclimatic diversity to understand how spatial distance-decay relationships are changing through time and across different facets of diversity. We found strong spatial distance decay of taxonomic similarity across all peaks, with the highest elevation peak showing the strongest decay. Functional and bioclimatic similarities decayed more weakly than taxonomic similarity, suggesting environmental filtering shapes trait and niche distributions. Critically, spatial decay patterns showed no temporal signal across facets of diversity, indicating community stasis rather than biotic homogenization or differentiation. This study adds further evidence that xeric alpine plant communities are resisting climate change impacts through time.

ecology↗

bioRxiv2019

Community turnover by composition and climate affinity across scales in an alpine system

Premise of the studyExamining community turnover across climate gradients at multiple scales is vital to understanding biogeographic response to climate change. This approach is especially important for alpine plants in which the relative roles of topographic complexity and non-climatic or stochastic factors vary across spatial scales.\n\nMethodsWe examined the structure of alpine plant communities across elevation gradients in the White Mountains, California. Using community climatic niche means (CCNMs) and measures of community dissimilarity, we explored the relationship between community composition and elevation gradients at three scales: the mountain range, individual peaks, and within elevation contours.\n\nKey ResultsAt the mountain range scale, community turnover and CCNMs showed strongly significant relationships with elevation, with an increase in the abundance of cooler and wetter-adapted species at higher elevations. At the scale of a single peaks, we found weak and inconsistent relationships between CCNMs and elevation, but variation in community composition explained by elevation increased. Within the elevation contours, the range of CCNMs was weakly positively correlated with turnover in species identity, likely driven by microclimate and other site-specific factors.\n\nConclusionsOur results suggest that there is strong environmental sorting of alpine plant communities at broad scales, but microclimatic and site-specific, non-climatic factors together shape community turnover at finer scales. In the context of climate change, our results imply that community-climate relationships are scale-dependent, and predictions of local alpine plant range shifts are limited by a lack of topoclimatic and habitat information.

ecology↗