Breeding waterbird wetland habitat availability and response to water-level management in Saint John River floodplain wetlands, New Brunswick

Abstract

Wetland management by the Eastern Habitat Joint Venture (EHJV) has focused primarily on water level control to increase the amount of available brood-rearing habitat for waterfowl along the Saint John River floodplain in New Brunswick. Impounded wetlands make up approximately 13% of the Saint John River Floodplain complex. Study objectives included an evaluation of waterfowl brood, and wetland obligate bird use of impoundments and seasonally flooded wetlands within the Saint John River floodplain. Historical water level data and a GIS wetlands inventory were used to estimate the duration of flooding on seasonally flooded wetland habitats, and the distribution and relative amount of brood-rearing habitat throughout the breeding period by region. Aerial brood surveys and call response surveys were used to estimate the relative abundance of waterfowl broods and breeding wetland obligate birds respectively. The overall density of waterfowl broods was greater on impoundments than on seasonally flooded wetlands during both years of study but varied by site. Mean species richness of wetland obligate birds was significantly greater on impoundments than on seasonally flooded wetland habitat. Generally, use of seasonally flooded wetlands by wetland obligate birds during late summer declined while the use of impoundments increased. Current habitat management for waterfowl appears to be compatible with habitat requirements of wetland obligate birds by increasing the availability of interspersed open water and emergent vegetation throughout the breeding season. A watershed-based analysis of wetland habitat suggests future wetland management should focus on enhancing current impoundments within the Saint John River floodplain. Resources must be secured for maintenance and water level manipulation within existing managed wetlands rather than the construction of additional impoundments. Further evaluation of the distribution of wetland habitat types in the province is essential to identifying focus areas for waterbird conservation throughout NB.

Effects of Human Activities on the Diversity of Waterbirds Wintering in a Shallow Lake of the Middle and Lower Yangtze River Floodplain, China

“…The results suggest that artificial wetlands can become a temporary substitute habitats for wintering waterbirds for relatively short periods. As socioeconomic development occurs, and populations increase, more natural wetlands are converted into artificial hydrologically-controlled habitats [32,33], which, in turn, changes vegetation quality [34]. As substitute habitats for natural wetlands, researchers are increasingly paying attention to artificial wetlands in waterbird conservation efforts, as they are potential substitute habitats for natural wetlands [35,36].…”

Prediction of change in wetland habitats by groundwater: case study in Northeast Lithuania

“…Additional research indicates considerable biological changes in the shallow ecosystems and littoral zones, where even small fluctuations of water level cause fundamental habitat changes (Blindow et al 1993;Coops et al 2003;Beklioglu et al 2006;Leira & Cantonati 2008). Other studies suggest that waterfowl are very sensitive to changes in their habitat area, especially during the breeding season (Hake et al 2005;Connor & Gabor 2006).…”

“…Many relevant studies deal with the responses of aquatic ecosystems to natural and artificial water level changes (Riis & Hawes 2002;Schmieder 2004;Chow-Fraser 2005;Coops & Havens 2005;Hudon et al 2005;Connor & Gabor 2006;Desgranges et al 2006;Wilcox & Xie 2007). According to various research results, the fluctuations of water level greatly influence the area of waterfowl habitats as well as the rate of biomass accumulation in aquatic ecosystems (Casanova & Brock 2000;Van Geest et al 2005;Paillisson & Marion 2006).…”

Water Birds Of Sinnar Dam Reservoir

“…Artificial wetlands are those that are created or extensively modified by humans, including paddy fields, salt ponds, aquacultural ponds, impoundments and reservoirs. Although artificial wetlands cannot completely replace the functions of natural ones as water bird habitats [4] researchers and managers widely recognize that artificial wetlands can provide alternative or complementary habitats for water birds in all life stages [5] and consequently, can partially mitigate the adverse influences of loss and degradation of natural wetlands ( Figure 1).…”