COS 62-6 - CANCELLED - Nutrient deposition and drought effects on arthropod herbivore damage in longleaf pine savanna understory

Abstract: Herbivory, a key ecosystem process, ensures the cycling of energy and nutrients. By feeding on plants, herbivores impact primary production and plant community composition and structure with consequences for biodiversity, function, and economic value. Herbivory is a particularly important driver of grassland and savanna dynamics. In grasslands, the more inconspicuous insect herbivores can account for the majority of herbivory. Sadly, worldwide insect abundance and biodiversity are being lost at alarming rates. Understanding arthropod herbivory and the role it plays in structuring ecosystems is particularly critical now as the current insect apocalypse unfolds.

Insects are the primary herbivore in the longleaf pine (LLP) savanna which lost its larger herbivores centuries ago. LLP savanna, once expansive throughout the southeastern United States, is now among the most critically threatened ecosystems with 4% of its historical range remaining. Managed properly at small scales, this ecosystem is one of the most ecologically diverse in the world. Over 900 plant and animal species reside in its understory, and the titular tree has been lauded as ‘The tree that built the South’, making LLP savanna both economically and ecologically valuable to restore and conserve. Restoration and conservation success in LLP savannas is threatened by numerous global change factors, including drought and nutrient deposition. Understanding the role of arthropod herbivores and how global change may interact with and alter herbivory is critical for conducting successful restorations in the Anthropocene.

My research aims to understand how global change, specifically nutrient deposition and drought, will interreact to affect a key disturbance in herbaceous-dominated systems – herbivory. I will assess this by utilizing an existing long-term (4 years total) drought and nutrient experiment in healthy, xeric longleaf pine savanna in the Sandhills Gamelands of Richmond County (NC). I aim to:

1. Quantify drought and nutrient addition impact on herbivore damage in five dominant understory plant species and determine how herbivore damage changes through time across two timescales

2. Determine the importance of various mechanisms in driving changes in magnitude of herbivore damage

Sustainable and environmentally friendly land management is challenging, and global change complicates this further. In the face of these changes, my goal is to inform sustainable practices for restoration and the management of natural resources with arthropods in mind. Understanding the roles they play – both good and bad – and how these roles may differ in the future will help land managers prepare for the changes to come.