CR 69:117-128 (2016)  -  DOI: https://doi.org/10.3354/cr01398

ABSTRACT: Perceived inconsistencies in the way a species may respond to temperature change across its thermal range can create confusion about the effects of climate change. Confusion can create doubt about the effects of temperature on a species, which can lead to controversy among scientists, ecosystem managers, and the general public. All this arises because empirical studies often take place at local scales, where responses to temperature can be quite different and where population dynamics can often appear to be random. At local scales, the long-term relationship between abundance and temperature can describe one of 3 scenarios: (1) a nil, (2) a negative, or (3) a positive relationship. Here, by showing that differential, regional biological responses to temperature are to be expected from ecological theory, we demonstrate that the 3 different responses to temperature depend upon the interaction between a species’ thermal niche, the thermal local regime and its changes, and the magnitude of stochastic or uncontrolled processes. Using models mixing nonlinear, deterministic, and stochastic processes, we suggest that species’ responses to climate change are quasi-deterministic at some spatial scales, enabling them to be theorised and anticipated, thereby removing future controversy.

KEY WORDS: Marine species · Climate change · Ecological theory · Temperature