Functional Equivalence of Created Wetland Water Quality: A Comparison of Amphibian Metamorphic Success

Lauren A Mcpherson,Ida Holásková,James T Anderson

doi:10.4236/oje.2020.107027

Abstract

Wetlands are often created through wetland mitigation to replace lost natural wetlands, but further evaluation is needed to determine the ability of a created wetland to replace lost wetland functions, especially providing wildlife habitat. We used a mesocosm design to compare the water quality between three created wetlands and three natural wetlands in West Virginia, USA and to evaluate how the water quality from the two wetland types were able to support metamorphosis in larval spring peepers (Pseudacris crucifer) and wood frogs (Lithobates sylvaticus) across two years (2014-2015). Responses in metamorphosis rates differed between species and between years. Spring peepers displayed similar metamorphosis rates in the created and natural wetlands in both years of the study. Wood frogs displayed similar metamorphosis rates in created and natural wetlands in 2015, but in 2014 wood frogs reached metamorphosis in less time and at a larger body size in the natural wetlands, suggesting that the wood frogs that developed in the natural wetlands may have higher fitness than those that developed in the created wetlands. Water quality was largely similar between created and natural wetlands, although dissolved oxygen, conductivity, and pH varied between mesocosms and wetlands. Our study suggests that created wetlands may be providing partial mitigation in terms of water quality for amphibian development. We recommend that future monitoring of created wetlands include measures of juvenile amphibian recruitment as well as additional habitat variables to better determine the ability of created wetlands to function as amphibian habitat.

Highlights

Wetland mitigation aims to replace lost wetlands through the creation or restoration of new wetlands, it is unclear whether mitigation projects adequately replace wetland function
Wood frogs displayed similar metamorphosis rates in created and natural wetlands in 2015, but in 2014 wood frogs reached metamorphosis in less time and at a larger body size in the natural wetlands, suggesting that the wood frogs that developed in the natural wetlands may have higher fitness than those that developed in the created wetlands
When we compared water quality between the mesocosm pool and the source wetlands, we found that pH, temperature, and nitrogen were similar between the pools and the wetlands (Table 2)

Summary

Introduction

Wetland mitigation aims to replace lost wetlands through the creation or restoration of new wetlands, it is unclear whether mitigation projects adequately replace wetland function. Many of the studies evaluating the success of created wetlands focus on the three primary wetland characteristics [7]: hydric soils [8] [9], hydrophytic vegetation [2] [9] [10] [11] [12], and hydrology [3] [13]. Each of these studies results in differing conclusions about the functional success of wetland mitigation. The ability of a created wetland to replace lost wildlife habitat and to support wildlife populations are important factors to include in the assessment of created wetland success

Methods

Results

Conclusion