Today’s landscape is fragmented by roads, cities and farms. Within the United States, these disturbed areas transect millions of acres of natural habitats where plants and animals thrive. Many of the organisms living within these natural patches will need to track their preferred habitats as climates shift. We examine to what extent fragmented landscapes prevent those organisms living in natural patches from tracking their current temperatures across the contiguous US. Using human impact values, we identify remaining tracts of relatively natural lands across the contiguous U.S. We then calculate the coolest temperature that an organism living in a given natural patch could reach by moving through adjacent natural patches. We then connect those natural land patches with routes that allow species to move across existing temperature gradients while avoiding heavily impacted areas. We demonstrate where and by how much habitat fragmentation prevents plants and animals from being dynamically resilient to changing climates by tracking preferred climates.
Results/Conclusions
We demonstrate that only 41% of the remaining natural land area retains enough connectivity to allow plants and animals to track current temperatures as the climate warms into the future. In the eastern U.S., less than 2% of natural area is sufficiently connected. Introducing corridors to facilitate movement through human-dominated landscapes increases the percentage of climatically connected natural area to 65%, with a 25% increase in the East and a 24% increase in the West. The most impactful gains occur in low-elevation regions, particularly those in the southeastern U.S. We find that human impacts limit the ability of organisms to track their current temperatures by 24%. This study demonstrates that climate connectivity analyses can allow ecologists and conservation practitioners to determine the most effective regions for increasing landscape connectivity to mitigate the effects of climate change. More importantly, we demonstrate that increasing connectivity is critical for allowing species to track rapidly changing climates.