SPECIES RANGE EDGES

[PUBLICATION] Range edges in heterogeneous landscapes: Integrating geographic scale and climate complexity into range dynamics.

Figure showing the relationship between geographic and climate edges

Overview

This research, published in Global Change Biology (2020), investigates how the relationships between geographic space and climate space influence species range dynamics, particularly in topographically complex landscapes. As a co-author on this paper led by Meagan Oldfather, I led the empirical portion of the study, developing the analytical framework and data analyses examining how climate heterogeneity, collinearity, and spatial scale interact to shape species distributions.

Key Contributions

Our paper challenges the common assumption that geographic range edges consistently align with climate niche limits. Through extensive data analysis of North American tree distributions, we demonstrated that:

Geographic range edges and climate edges show surprisingly weak correlation (mean r ≈ 0.25 across 662 tree species)
Climate heterogeneity and climate variable collinearity interact to create diverse relationships between geographic and climate space
Future climate change will often create conditions where species cannot simultaneously track multiple climate variables due to spatial constraints

Methodological Innovation

We developed novel analytical approaches to quantify the relationships between:

Distance to geographic edge and distance to climate edge for hundreds of species
Climate heterogeneity and collinearity across global landscapes
Alignment between spatial climate relationships and predicted climate change trajectories

Implications

These findings have significant implications for predicting species vulnerability to climate change. In particular, our work shows that populations at the geographic center of a species' range may sometimes be more vulnerable to climate change than those at the range edge, challenging conventional conservation approaches that prioritize peripheral populations.

This research contributes to a more nuanced theory of range dynamics that accounts for the complexities of real landscapes and provides a framework for more accurate predictions of climate change impacts on biodiversity.