Providing evidence to improve practice

Individual study: Biodiversity within restored wetlands in South Dakota, USA

Published source details

Juni S. & Berry C.R. (2001) A biodiversity assessment of compensatory mitigation wetlands in eastern South Dakota. Proceedings of the South Dakota Academy of Science, 80, 185–200

Background

Wetland mitigation is undertaken to compensate for human impacts to wetlands.  This study used a rapid biodiversity assessment technique to compare bird, fish, mammal, amphibian, reptile and invertebrate richness in created, restored, enhanced and natural wetlands in South Dakota, USA.

 

Action

Study sites were four created (in previous 10 years), four restored, four enhanced and five natural wetlands.  Creation tended to involve excavation or enclosing a small stream.  Restoration tended to involve plugging drainage ditches or breaking sub-surface drainage tiles.  Enhancement included manipulating water levels to increase wetland size or changing vegetation structure.

Wetlands were surveyed using a rapid biodiversity assessment technique in spring and autumn in 1999-2000.  Monitoring involved point counts for birds, fyke nets, drift-fences and pitfall traps, live-traps, aquatic invertebrate traps and visual surveys around wetland perimeters.

 

Consequences

A total of 76 bird, nine fish, 11 amphibian and reptile and 16 mammal species and 52 aquatic invertebrate taxa were recorded in the wetlands.

There were significantly higher numbers of invertebrate taxa in restored than created or enhanced wetlands and more in natural than created wetlands.  Diversity did not differ between wetland types.

There were no significant differences between bird richness or diversity, or species richness for fish, amphibians and reptiles or mammals in created, restored, enhanced and natural wetlands.   Although not significant, there was a trend for higher numbers of species of birds in restored wetlands, fish in created then restored wetlands, amphibians and reptiles in restored then enhanced wetlands and mammals in restored and created wetlands compared to natural wetlands.