A new NSF DEB grant to Mike Kaspari and Nate Sanders supports a 3-year postdoc who will join us to explore the Geographical Ecology of invertebrate plant consumers across North American grasslands, meadows, and roadways. Our focus is on the role sodium and other micronutrients play as unique catalysts of the vigor, abundance, activity, and diversity of above- and below-ground communities. We will combine geographical snapshots from across North America with field and lab experiments to identify and explore mechanisms. It will be grand.

We are looking for an ecologist with expertise in invertebrate ecology and an interest in testing big picture models that combine Ecological Stoichiometry, Metabolic Ecology, and Trophic Ecology. Proposed starting date as soon as January 2017. To apply, email Mike Kaspari (mkaspari@ou.edu) your CV and a letter of introduction that includes a summary of your most relevant research experience, your future research plans, and contact info for at least two references. Check out our lab’s webpage at michaelkaspari.org.

OU Biology is dedicated to growing our already considerable expertise in Geographical Ecology, including a recently completed cluster hire of three ecologists with expertise in physiological ecology, macroecology, and aquatic ecology. Join us!

NSF Project Summary

Overview

Plant populations transform CO₂, water, and nutrients into tissue; detritivore and herbivore populations consume and ultimately mineralize that tissue. Geographical ecology predicts how the abundance of these populations (and their summed activity as net primary productivity, decomposition, and herbivory) covary across Earth’s ecosystems. This proposal offers a timely focus on the role of sodium as a catalyst driving the abundance and activity of plant consumers. It builds on recent work highlighting three features placing sodium at the hub of terrestrial ecology: 1) the many ways that Na availability is non-randomly distributed among Earth’s terrestrial ecosystems, 2) the failure of Na shortage to decrease plant fitness, and 3) the necessity for plant consumers to find and retain sufficient Na supplies. Combined, these elements form a framework that posits Na shortfall as a key constraint on herbivores, pollinators, detritivores, and their summed effects on communities and ecosystems. Moreover, other drivers of geographical ecology are either catalyzed by Na—adding it allows consumers to better use available N and P—or exacerbate Na shortfall–as temperatures increase, so do Na loss rates.

Field and lab experiments will be combined with comparative community studies to test how the effects of Na shortage are enhanced at higher temperatures, in ecosystems inland from oceanic aerosols, and in the absence of road salt application. In the first year, geographical variation in the abundance, behavior, and stoichiometry of focal populations will be quantified among 40 grasslands/old fields paired with associated roadsides of mesic North America. In the following two years, 7×7 m plots will be fertilized with Na in quantities mimicking oceanic aerosols, into which N and P fertilization plots are embedded. The goal will be to explore how Na shortage acts as a catalyst for plant consumers, one that decreases their activity, consumption, and N and P use efficiency relative to the plants they eat and the predators that consume them.

Intellectual Merit

Four drivers—temperature, precipitation, N, and P—have been key in predicting the geography of plant productivity. Ecology lacks an equivalent understanding of the abundance and activity of plant consumers. This proposal offers two remedies toward transforming geographical ecology. The first is a framework by which a third, powerful driver of herbivores and detritivore acts independently of plant productivity. The second is a test of this Na framework via a systematic exploration of invertebrate grassland consumers across mesic North America. If successful, this project has the potential to jump-start the biogeography of trophic structure and carbon cycling by focusing on Earth’s ubiquitous Na gradients.

Broader Impacts of the Proposed Work

We envision three. We link climate and biogeochemistry to build novel predictive models useful to community and ecosystem ecologists. In doing so, we help jump-start NEON, and build the nascent field of Roadside Ecology. We foster graduate STEM education. Given the extraordinary pace of change in how we “Do Ecology”, we will address the need for an evolving source of information on best practices with a curated living online document. We foster undergraduate STEM education. Sodium Catalyst theory is a rich source of ideas that are easily tested. We will mentor undergrads on our projects to develop and test some of these low-hanging fruit. Kaspari will develop and publish a series of three labs from his Principles of Ecology course that focus on the geography, trophic, and pollination ecology of sodium.