Dynamics of the species ranges in a changing climate

Abstract

Evidence is mounting that ongoing climate change is leading to a globally consistent fingerprint of systematic shifts in species distributions, and they are estimated to be 2.5 times greater than previously anticipated. In particular, a series of commonly articulated hypotheses have emerged that species are expected to shift their distributions to higher latitudes or elevations, and deeper depths in response to climate change, reflecting an underlying assumption that species will move to cooler locations to track spatial changes in the temperature. However, many species are not demonstrating range shifts consistent with these hypotheses, because species do not necessarily move along the linear temperature gradients. Their distributions are influenced by many interconnected factors, such as precipitation, land-use change, physical barriers, species trait, population dynamics, invasive species, interspecific species interactions and microclimate conditions. Understanding how species distribution changes in response to climate change is enormously complex. Providing effective explanations for the observed variability in species’ range shifts requires, firstly, that method used for detection of distributional changes are able to distinguish between directional and non-directional changes and secondly, that they are able to distinguish distributional changes driven by natural population dynamics from changes driven by external forcing (climatic or non-climatic).