Accounting for dispersal in climate change planning

Dispersal is one of the most critical process for species adaptation to climate change, as the driver for both colonization of new habitat and the spread of genes that underlie evolutionary adaptation.  When accounting for dispersal in planning for species’ response to climate change, it’s important to consider not only how species will move but how climate change itself might alter dispersal characteristics.  In their forthcoming Oikos paper, Travis et al. argue that conservation strategies would be greatly enhanced by explicitly including not only dispersal characteristics, but also the uncertainty in dispersal evolution resulting from climate change.  Their perspectives paper raises several key questions:

1. Will climate change reduce or enhance individual dispersal abilities?  Climate change will lead directly to changes in abiotic environmental conditions, which can impact an individual’s dispersal path through indirect means (ex. altering the physical landscape via fragmentation) and direct means (ex. causing biophysical adaptations that change body morphology).  Additional factors, such as interspecies interactions and altered phenologies, have the potential to increase or decrease dispersal abilities both across and within individual species.

2. How will dispersal evolve under climate change?  Previous studies have shown increased dispersal at expanding range margins, which influences how species may spread (non-uniformly) through heterogeneous landscapes.  The evolution of dispersal is ultimately tied to the unknown complexity of the balance between genetic processes and phenotypic plasticity.

3. How is dispersal included in predicting species’ future distributions?  Habitat suitability models that predict future species distribution have only recently started to explicitly include dispersal characteristics.  The shift towards more mechanistic models that allow dispersal to vary in both space and time could create more realistic models that reflect the variation in individual dispersal probabilities.

4. How do conservation strategies for climate change account for dispersal?  With a shift in management focus toward large scale, spatially dynamic landscapes, connectivity models often include basic dispersal processes, although they don’t always capture the complexity of colonization based on multiple dispersal factors.

The authors conclude with recommendations of where to focus future efforts, which include: a) increase the number of large-scale data sets that collect across multiple scales to allow for meta-analyses of numerous species; b) represent dispersal more realistically with a mechanistic approach that merges movement models and population dynamics; c) incorporate within-species variability in dispersal to create a range of probable future range limits; d) increase empirical knowledge on how genetic processes and life-history traits may affect dispersal evolution; and e) account for different phases of dispersal in land management decisions to create more effective and efficient assisted dispersal.  Given the inevitability of some type of human intervention for species adaptation to climate change, incorporating more realistic patterns of dispersal and how it may evolve could be the key to facilitating successful adaptations for a large number of species.