Wetland creation is a common means for offsetting wetland losses, but do manmade wetlands truly function as well as their natural counterparts?

An article titled “Amphibian Reproductive Success as a Gauge of Functional Equivalency of Created Wetlands in the Central Appalachians” by GAI Senior Environmental Specialist Gabriel F. Strain, PhD and other contributors published recently in Wildlife Research finds that manmade wetlands support breeding of certain frogs just as successfully as natural wetlands—results that suggest manmade wetlands may function similarly to natural wetlands. Wildlife Research is published by CSIRO Publishing; click here to download Dr. Strain’s article. An abstract of the article is provided below.

For related writings, check out the following article by Gabriel F. Strain, PhD:
Anuran Occupancy of Created Wetlands in the Central Appalachians,” published December 2016 in journal Wetlands Ecology and Management.

Gabriel Strain, PhDGabriel F. Strain, PhD specializes in the study of ecology and wildlife. His experience in the field includes the study and identification of northeastern U.S. amphibians, reptiles, and benthic macroinvertebrates, as well as wetland and stream delineation. He has knowledge of fish and tree identification and the use of common sampling techniques for amphibians, reptiles, fish, small mammals, and benthic macroinvertebrates.

For questions or additional information, contact GAI Consultants’ Senior Environmental Specialist Gabriel F. Strain, PhD at 610.640.7456.


Context. Evaluating the adequacy of created wetlands to replace the functions of lost natural wetlands is important because wetland mitigation is a major tool used to offset wetland losses. However, measurements such as vegetative cover and presence of wildlife may not provide sufficient evidence that created wetlands are functioning properly. Thus, examining the ecology of wetland biota such as that of amphibians may be a more useful surrogate for function.

Aims. The objectives of this study were to compare the abundance of amphibian metamorphs and survival and growth of larval amphibians in created wetlands, relative to natural wetlands.

Methods. Amphibian metamorphs were trapped in created and natural wetlands during the spring (April–May) and summer (June–August) of 2009 and 2010, and 165 green frog (Lithobates clamitans) larvae were raised during the spring of 2010 in laboratory aquaria containing water from created or natural wetlands.

Key results. Abundance of spring peeper (Pseudacris crucifer) metamorphs decreased significantly from 2009 to 2010 and abundance of green frog metamorphs increased with habitat complexity, but both were unaffected by wetland type. Detection probability of metamorphs of both species was low, increased with water temperature and declined with month of observation. Survival, growth curves and mass were similar among green frog larvae raised in created and natural wetland aquaria.

Conclusions. Our results suggest that the created and natural wetlands we examined function similarly with respect to providing adequate breeding habitat for green frogs and spring peepers.

Implications. Wetlands created to offset the loss of natural wetlands, although generally not designed for the purpose of wildlife habitat, can function as adequate breeding habitat for generalist amphibians such as green frogs and spring peepers.

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