Range deformation: consequences of range shifts during climate change

OVERVIEW

The intellectual motivation for ecological and evolutionary research is to explain the distribution of biodiversity across the globe (“why is what where”). This research now finds itself at the centre of immense interest from society, as climate change is expected to produce large-scale spatial shifts in biodiversity.

Populations are unlikely to simply track the climates they now inhabit. Lags may be introduced by a number of endogenous factors primarily those determining to (1) colonisation and so access to newly available, unoccupied habitat, and (2) extinction which determines rates of extirpation from occupied habitat. Exogenous factors, such as habitat loss-fragmentation-geometry, may also play an important role in determining the strength of these lags through density dependent emigration and spatial selection.

Very importantly there is no reason for either of these lags to be equal and maintain the pre climate change range size, shape and population’s relationship to climate. The action of multiple processes need not have exactly compensating effects. Instead populations are likely to change in shape and size, even when environmental conditions are present in exactly the same amounts.

Deformation of populations’ ranges (change in shape, size and relationship to the environment) are the likely consequence of climate change (Range Deformation see: Rapoport 1975), altering the spatio-temporal dynamics of populations’ and the context of biotic interactions. Very importantly there are considerable changes in the evolutionary dynamics for the above stated reasons.

Key evolutionary changes may be driven by the iterated founder effects during range shifts causing changes in neutral dynamics, exposure to novel environments or exposure to previous environments but within a different population context may alter adaptive dynamics and changes in gene flow may alter perceptions of symaptry within populations leading to speciation.

In this research track the large scale consequences of these issues (e.g. biogeographic patterns) are considered when investigating the mechanisms causing range deformation. Using simulation modelling and microcosm experiments new hypotheses about how to make predictive ecological models are explored. With this understanding we may approach better predictive models of natural systems as we better answer the “why is what where” question. Ultimately we will be exploring new explanations for patterns of global diversity.  

 

We are interested in understanding biotic responses to the world’s worst experiment - Climate Change. It is an experiment of immense scale and will offer great insights into how ecological systems work, but the experiment has not been thoughtfully designed and contravenes nearly all aspects of experimental good practice. Interestingly, some groups do not even acknowledge the existence of the experiment. The experiment is littered with confounding factors. Not only is the study system affected by the treatment (climate change), but there are many other experiments simultaneously taking place (habitat loss; habitat fragmentation; habitat deterioration; exploitation;... etc). Considerable interactions between the focal (climate change) and other experimental treatments are expected. As there is a single replicate (earth), our ability to conduct future experimentation may depend on predicting the experimental outcome in the early stages (conservation). This problem is compounded by our lack of prior knowledge of the system (science). Irretrievable loss of our experimental material (biodiversity) is expected to occur during the experiment but we did not know exactly what the system contains at the beginning (data). More importantly the experiment is undertaken without an appropriate understanding of the system properties (ecology; evolution) in ‘static’ conditions, or in response to the confounding factors referred to above. Thus our hypotheses will develop as we go on.
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