When Indices of Condition Don't Tell Us About Wetland Function

Wetland loss has been significant across the globe. Those that remain are vulnerable to the effects of surrounding land use and are in some cases subjected to biotic homogenization. To monitor the condition of these wetlands, we commonly focus on gathering information about their surrounding land use, onsite stressors, and vegetative communities. The question remains: are these good indicators of a wetland’s functions, such as those performed in full or in part by microbes? We investigated this question in headwater wetlands of Pennsylvania and Ohio, focusing on pools and fluxes of the carbon and nitrogen that regulate water quality and climate change. While some pool (e.g., carbon storage) and flux (e.g., soil 15N) measurements were correlated with condition gradients derived from land use and onsite characterizations, rarely did we find congruence across regions (e.g., carbon accretion) Many functions fail to be explained without first accounting for other landscape gradients (e.g., soil texture’s effects on denitrification). Given these findings we ask, are there innovative ways for monitoring function that can be implemented in our monitoring programs in the future?

Impact/Purpose

Ecologists in the wetland community have long debated whether information about surrounding land use, onsite stressors, and vegetative communities used to define wetland condition relate to wetland function. In this study, we investigated pools and fluxes of carbon and nitrogen, important to the wetland functions of water quality regulation and climate amelioration, in headwater wetlands of Pennsylvania and Ohio. In addition, we collected information from each wetland to determine condition. We found that some pool (e.g., carbon storage) and flux (e.g., soil 15N) measurements were correlated with wetland condition gradients derived from land use and onsite characterizations; however, for some measurements, like carbon accretion, we rarely found congruence across regions. Furthermore, many functions fail to be explained without first accounting for other landscape gradients (e.g., soil texture’s effects on denitrification). We hope to inform monitoring programs with innovative ways for monitoring function, in addition to condition, in the future.

Citation

Moon, J., D. Wardrop, M. Fennessy, H. Ingram, AND A. Nahlik. When Indices of Condition Don't Tell Us About Wetland Function. Society for Freshwater Science Annual Meeting, NA, Virtual, May 23 - 27, 2021.