Multiple axes of ecological vulnerability to climate change

Abstract

Observed ecological responses to climate change are highly individualistic across species and locations, and understanding the drivers of this variability is essential for management and conservation efforts. While it is clear that differences in exposure, sensitivity, and adaptive capacity all contribute to heterogeneity in climate change vulnerability, predicting these features at macroecological scales remains a critical challenge. We explore multiple drivers of heterogeneous vulnerability across the distributions of 96 vegetation types of the ecologically diverse western US, using data on observed climate trends from 1948 to 2014 to highlight emerging patterns of change. We ask three novel questions about factors potentially shaping vulnerability across the region: (a) How does sensitivity to different climate variables vary geographically and across vegetation classes? (b) How do multivariate climate exposure patterns interact with these sensitivities to shape vulnerability patterns? (c) How different are these vulnerability patterns according to three widely implemented vulnerability paradigms-niche novelty (decline in modeled suitability), temporal novelty (standardized anomaly), and spatial novelty (inbound climate velocity)-each of which uses a distinct frame of reference to quantify climate departure? We propose that considering these three novelty paradigms in combination could help improve our understanding and prediction of heterogeneous climate change responses, and we discuss the distinct climate adaptation strategies connected with different combinations of high and low novelty across the three metrics. Our results reveal a diverse mosaic of climate change vulnerability signatures across the region's plant communities. Each of the above factors contributes strongly to this heterogeneity: climate variable sensitivity exhibits clear patterns across vegetation types, multivariate climate change data reveal highly diverse exposure signatures across locations, and the three novelty paradigms diverge widely in their climate change vulnerability predictions. Together, these results shed light on potential drivers of individualistic climate change responses and may help to inform effective management strategies. K E Y W O R D S biogeography, climate change, climate departure, climate velocity, niche model, novel climate, resource management, vegetation, vulnerability

Points of view matter when assessing biodiversity vulnerability to environmental changes

“…Managing the complexities of measuring and linking measures of exposure, sensitivity and adaptive capacity could be achieved by framing their assessment within a well‐defined vulnerability paradigm which describes the response mechanism of the biological entity of interest (Figure 1). This perspective is the one taken by Kling et al (2020). They propose three alternative vulnerability paradigms, each centred on an alternative definition of how biodiversity could respond to changing environmental conditions.…”

“…However, assessing biodiversity responses to observed or expected changes in environmental conditions is a multifaceted problem, where the point of view used to determine both the drivers and the degree of change matter. In this issue of Global Change Biology , Kling, Auer, Comer, Ackerly, and Hamilton (2020) tackle these problems by focusing on two of the facets (observed multivariate climate change and limiting environmental factors) defining how biodiversity may respond to climate change. Then they combine these facets to show how biodiversity could respond to novel climatic conditions under alternative paradigms of response.…”

“…This focus on impact mechanisms is central for translating vulnerability assessments into actionable conservation, mitigations and adaptation plans. Furthermore, the results of Kling et al (2020) show how a multi‐paradigm perspective is necessary to get the full picture of biological vulnerability to environmental change.…”

“…Decisions of where and how to invest the limited resources available for conservation need the support of vulnerability assessments grounded on precise impact mechanisms and the best available information. Kling et al (2020) have taken the first steps in this direction, by highlighting the need to frame vulnerability assessments under a specific paradigm, and the need to analyse the interaction between vulnerability paradigms when defining suitable conservation, management and adaptation strategies.…”

Habitat Climate Change Vulnerability Index Applied to Major Vegetation Types of the Western Interior United States

“…Using distributions that have been affected by land conversion could skew how we define climate suitability for a vegetation type and hence, how we measure climate exposure. Kling et al [35] provide additional detail on component model design and performance.…”