The geography of climate change: implications for conservation biogeography

Abstract

Aim Climate change poses significant threats to biodiversity, including impacts on species distributions, abundance and ecological interactions. At a landscape scale, these impacts, and biotic responses such as adaptation and migration, will be mediated by spatial heterogeneity in climate and climate change. We examine several aspects of the geography of climate change and their significance for biodiversity conservation. Location California and Nevada, USA. Methods Using current climate surfaces (PRISM) and two scenarios of future climate (A1b, 2070–2099, warmer‐drier and warmer‐wetter), we mapped disappearing, declining, expanding and novel climates, and the velocity and direction of climate change in California and Nevada. We also examined fine‐scale spatial heterogeneity in protected areas of the San Francisco Bay Area in relation to reserve size, topographic complexity and distance from the ocean. Results Under the two climate change scenarios, current climates across most of California and Nevada will shrink greatly in extent, and the climates of the highest peaks will disappear from this region. Expanding and novel climates are projected for the Central Valley. Current temperature isoclines are projected to move up to 4.9 km year−1 in flatter regions, but substantially slower in mountainous areas because of steep local topoclimate gradients. In the San Francisco Bay Area, climate diversity within currently protected areas increases with reserve size and proximity to the ocean (the latter because of strong coastal climate gradients). However, by 2100 of almost 500 protected areas (>100 ha), only eight of the largest are projected to experience temperatures within their currently observed range. Topoclimate variability will further increase the range of conditions experienced and needs to be incorporated in future analyses. Main Conclusions Spatial heterogeneity in climate, from mesoclimate to topoclimate scales, represents an important spatial buffer in response to climate change, and merits increased attention in conservation planning.

Strengths and Weaknesses of Quantitative Climate Reconstructions Based on Late-Quaternary Biological Proxies

“…It is questionable whether such gridded or interpolated climate data reflect the actual alpine environment where the majority of organisms live in microhabitats strongly decoupled from atmospheric conditions and interacting with micro-topography at a very fine spatial scales (Lookingbill & Urban 2003;Scherrer & Körner 2010. Spatial heterogeneity in climate is a very important environmental feature and is of critical importance in the reliability and usefulness of bioclimate-envelope models that use mesoscale climate data (Ashcroft et al 2009;Ackerly et al 2010;Bennie et al 2010). When the biological distribution data are derived from distribution maps and atlases, the altitudes at which the species grow are often unknown so the climate data from lowland climate stations used in MCR are likely to be ecologically unrealistic.…”

Landscape-scale indicators of biodiversity's vulnerability to climate change

“…Researchers are highlighting the importance of identifying and protecting landscape-scale features such as topographic and climatic heterogeneity, elevation gradients, solar insolation, soil types, geology, and riparian corridors to aid species' adaptation to climate change (Peterson 2003, Seavy et al 2009, Ackerly et al 2010, Anderson and Ferree 2010, Beier and Brost 2010, Dobrowski 2011. Our method combines this information with climate change stress and potential constraints to adaptation to provide a map of climate adaptation strategies.…”

“…In addition, there have been significant concerns raised about the methodology and performance of these models (Pearson and Dawson 2003, Hampe 2004, Beale et al 2008. While detailed vulnerability assessments for select well-studied species are possible for some managers (Hannah et al 2007, Hannah et al 2008, the costs and data requirements make a comprehensive study of all of the species in an area impractical (Williams et al 2008, Ackerly et al 2010. Even managers with larger research budgets and sufficient technical capacity will need new tools to complement their species vulnerability assessments to generate strategies for lesser-known species.…”

Local patterns of diversity in California northern coastal scrub

“…While California's coastal zone harbors a significant percentage of the plant diversity within the CFP, it is also heavily impacted and threatened by altered ecological processes due to development (Tang, 2008), invasive species (Dukes & Mooney, 2004), and climate change (Ackerly et al., 2010). Our objectives are to assess patterns of diversity within NCS as a first step to conservation efforts.…”