Globally-distributed ecology

[Dummy caterpillar at Zackenberg, Greenland (photo: Tomas Roslin)]

Process-level ecological data is usually collected locally, making scaling to the landscape and global scale a dubious exercise. I’m collborating with two projects that seek to remedy this deficiency by using global distributed experiments.

Geographic gradients in species interactions

Species diversity generally increases towards the Equator, and the extent to which this affects species interactions will have profound biogeographic and evolutionary consequences. Despite decades of local experimentation and extrapolation, we still lack a globally-coherent picture of interaction strength.

The Global Dummy Caterpillar Project deployed plasticine caterpillar mimics around the world to measure predation rates by multiple taxa, distinguished by mouth marks left in the plasticine. We found strong evidence of higher predation in the tropics with a parallel pattern over elevation with stronger predation in the lowlands.

Collaborators:

  • Global Dummy Caterpillar Project Network
  • Colleen Nell, University of California, Irvine
  • Tomas Roslin, Swedish University of Agricultural Sciences

PlantPopNet: Scaling up demography

Demographic models provide powerful insight into the life history processes that control individual fitness, population growth, and extinction risk. Demographic studies to-date are too poorly replicated in space and time to tease apart the complex ways that demographic processes respond to environmental variation—-this is a key blindspot in our understanding of fundamental population processes made more glaring in light of global change, elevated extinctions, and species invasions.

PlantPopNet is focusing on collecting demographic vital rates for a cosmopolitan plant, Plantago lanceolata, all over the world. By comparing individual performance across environments, we are beginning to understand how different life history processes respond to the environment and scale up to impact population dynamics.

I have established five replicate monitoring populations across a broad environmental gradient in California, from the mediterranean south to the mesic redwood forests of the north. These data will be pooled with ca. 25 other sites in the network to form the largest demographic database for any single species.

Collaborators: