Influences of Design and Landscape Placement Parameters on Amphibian Abundance in Constructed Wetlands

Abstract

As natural wetlands disappear, constructed wetlands may play vital roles in amphibian conservation. However, previous investigations have concluded that artificial wetlands do not adequately replace lost wildlife habitat. Nevertheless, constructed wetlands serve as breeding habitat for amphibians where extensive natural wetland loss has occurred. To investigate the roles of engineered wetland features on amphibian abundance, we surveyed 49 constructed wetlands throughout northern Missouri. Cricket frogs (Acris crepitans), bullfrogs (Lithobates catesbeianus), and leopard frogs (Lithobates blairi/sphenocephalus complex) each occurred in over 80% of surveyed wetlands. Salamanders and hylid frogs were rarely encountered. We used an information theoretic approach to examine relationships between individual species and habitat features associated with wetland designs and placements. We found that models incorporating design features of open water ponds best explained abundances of most commonly encountered species. At the placement level, models that included nearby aquatic habitat ranked highest for common species. Salamanders and most hylid frogs responded positively to aquatic vegetative cover but negatively to fish abundance and anthropogenic disturbance-related features in the landscape. Our results indicate that to be effective amphibian conservation tools, constructed wetlands should be fish-free, heavily vegetated, include shallows, and placed within areas of low anthropogenic disturbance.

Making leaps in amphibian ecotoxicology: translating individual‐level effects of contaminants to population viability

“…Because reductions in survival at metamorphosis were only evident when individuals were exposed to high Hg concentrations through both trophic and maternal pathways , reducing exposure through either route would alleviate most population-level effects. Reducing Hg exposure through larval diet may provide the most realistic target for remediation because amphibian breeding habitats are often small, discrete, and can be artificially constructed for some species (Shulse et al 2010). Our results suggest that if Hg contamination can be reduced within breeding habitats, or if uncontaminated alternative breeding sites can be created nearby, population-level effects of Hg might be reduced, even if adults continue to accumulate Hg in terrestrial habitats and pass it to offspring though maternal transfer (Bergeron et al 2010a).…”

Design guidelines for integrating amphibian habitat into golf course landscapes

“…A range of small natural wetlands (<0.2 ha) and large ponds (>2.0 ha) with open and closed canopy can provide suitable aquatic environments for breeding and larval development as well as enhance the connectivity between populations (Semlitsch, Boone, & Bodie, 2007). For constructed aquatic environments to aid conservation efforts, they must be free of predatory fish, have shallow vegetated littoral shelves and be located in areas with minimal disturbance from human activity (Shulse et al, 2010).…”

“…By integrating these general requirements into the layout, design and/or redesign of golf courses, these landscapes will be more suitable to the life cycle requirements of amphibians. However, conservation efforts should be directed towards locally threatened species (Hodgkison et al, 2007a(Hodgkison et al, , 2007bShulse et al, 2010) and local conservation authorities should be consulted to determine their specific habitat requirements.…”

“…Landscape composition is critical with this approach to ensure strong relationships between aquatic and terrestrial environments, to maintain connectivity between populations (Guerry & Hunter, 2002;Semlitsch, Conner, Hocking, Rittenhouse, & Harper, 2008) and to provide opportunities for pond-breeding amphibians to shift habitat in areas experiencing modifications to terrestrial environments . In order for golf course ponds to provide breeding habitat for species of conservation concern, they must be free of predatory fish and American Bullfrogs (Boone, Semlitsch, & Mosby, 2008;Kats & Ferrer, 2003;Shulse, Semlitsch, Trauth, & Williams, 2010) which requires seasonal drying regimes (Maret, Snyder, & Collins, 2006). With proper design, anthropogenic aquatic environments in suburban areas can serve as breeding habitats for amphibian populations while still serving their intended functions (Brand & Snodgrass, 2010).…”

Linking environmental drivers with amphibian species diversity in ponds from subtropical grasslands

“…Environmental heterogeneity at many scales is also important (Hamer and Parris 2011, Richter-Boix et al 2007, Shulse et al 2010, Silva et al 2011a, 2012, Werner et al 2009). Complex environments tend to have more microhabitats that allow differential resource use thereby favoring species coexistence (Campos and Vaz-Silva 2010, Cardoso et al 1989, Conte and Rossa-Feres 2007, Rossa-Feres and Jim 2001, Vasconcelos et al 2009…”