Biology subjects

Higgins, S. I.

Publications and source records attributed to Higgins, S. I..

3 recordsLinked to original sources

bioRxiv2023

Reassessment of the risks of climate change for terrestrial ecosystems

Forecasting the risks of climate change for species and ecosystems is necessary for developing targeted conservation strategies. Previous risk assessments mapped the exposure of the global land surface to changes in climate1-4 However, this procedure is unlikely to robustly identify priority areas for conservation actions because non-linear physiological responses and co-limitation processes ensure that ecological changes will not map perfectly to the forecast climatic changes. Here, we combine ecophysio{-}logical growth models of 135,153 vascular plant species and plant growth form information to transform ambient and future climatologies into phytoclimates, which describe the ability of climates to support the plant growth forms that characterise terrestrial ecosystems. We forecast that 33% to 68% of the global land surface will experience a significant change in phytoclimate by 2070 under RCP 2.6 and RCP 8.5, respectively. Novel phytoclimates without present-day analogue are forecast to emerge on 0.3-2.2% of the land surface, and 0.1-1.3% of currently realised phytoclimates are forecast to disappear. Notably, the geographic pattern of change, disappearance and novelty of phytoclimates differs markedly from the pattern of analogous trends in climates detected by previous studies1,3,4, thereby defining new priorities for conservation actions and highlighting the limits of using untransformed climate change exposure indices in ecologicaI risk assessments. Our findings suggest that a profound transformation of the biosphere is underway and emphasise the need for a timely adaptation of biodiversity management practices.

ecology↗

bioRxiv2023

Winners and losers under past and future climate change

Understanding the historical and physiological context of species vulnerabilities to climate change is a crucial step in predicting "winners" and "losers" under climate change. However, few studies have compared the magnitude and mechanisms of extant species responses to climate change in both the past and the future. By combining temporally contrasting range and niche projections, we show that range shifts in the next 50 years will need to be more extreme than in the past 6000 years to track climate niches in a large plant radiation. A new subset of physiological niche traits, particularly temperature and radiation tolerance, will be strong filters of range occupancy under anthropogenic compared with Holocene climate change. In the absence of migration, temperature niche shifts tracking the magnitude of climate change will also be required for many species to maintain their present ranges. Where range shifts occur, our results suggest that communities will be restructured differently in different habitats, with widespread range contraction in the mountains and potential latitudinal range expansion in the lowlands. Our study adds to a growing body of evidence that despite the threats posed by climate change to many species, not all species will experience unmitigated loss, and that it may be possible to predict which species are most at risk based on physiological and geographical traits.

ecology↗

bioRxiv2019

Diversification in evolutionary arenas -- assessment and synthesis

Understanding how and why rates of evolutionary diversification vary is a key issue in evolutionary biology, ecology, and biogeography, and the metaphorical concepts of adaptive radiation and evolutionary stasis describe two opposing aspects causing variation in diversification rates. Here we review the central concepts in the evolutionary diversification literature and synthesize these into a simple, general framework for studying rates of diversification and quantifying their underlying dynamics, which can be applied across clades and regions and across spatial and temporal scales. Our framework describes the diversification rate (d) as a function of the abiotic environment (a), the biotic environment (b) and clade-specific phenotypes or traits (c); thus d[~]a,b,c. We refer to the four components (a-d) and their interactions collectively as the Evolutionary Arena. We outline analytical approaches to this framework and present a case study on conifers, for which we parameterise the general model. We also discuss three conceptual examples: the Lupinus radiation in the Andes in the context of emerging ecological opportunity and fluctuating connectivity due to climatic oscillations; oceanic island radiations in the context of island formation and erosion; and biotically driven radiations of the Mediterranean orchid genus Ophrys. The results of the conifer case study are consistent with the long-standing scenario that low competition and high rates of niche evolution promote diversification. The conceptual examples illustrate how using the synthetic Evolutionary Arena framework helps to identify and structure future directions for research on evolutionary radiations. In this way, the Evolutionary Arena framework promotes a more general understanding of variation in evolutionary rates by making quantitative results comparable between case studies, thereby allowing new syntheses of evolutionary and ecological processes to emerge.

evolutionary biology↗