Modeling the effects of nutria(Myocastor coypus) on wetland loss

Abstract

We created a model to study the process in which nutria (Myocastor coypus) feeding activities lead to erosion and loss of marsh area. This model ties together data on nutria population dynamics and feeding behavior from the literature with data from field studies on the phenology of Scirpus americanus and Spartina patens conducted in the Barataria Basin, Louisiana, USA in 1992. The complete model consists of three linked models: a model of nutria population dynamics (nutria model), a model of the annual marsh biomass cycle of Scirpus americanus and Spartina patens (biomass model), and a plant-biomass densitydependent marsh area model (area model). When all three models are linked together, they form the "nutnabiomass-area mode1." Analysis of the models indicated the following. (1) The high population densities and low survivorship rates as reported in the literature are incompatible.(2) The nutria model is sensitive to adult and juvenile survivorship and, to a lesser extent, young born per female. It is not particularly sensitive to gestation periods, impregnation rates, or time to maturity. (3) The marsh area model is not sensitive to the marsh loss equation nor to the density at which loss of marsh area begins but is sensitive to the amount of biomass destroyed per nutria. (4) Nutria numbers do not significantly decrease in the nutria-biomass-area model until the total marsh area approaches zero because marsh loss occurs only during winter when marsh biomass is at its annual low.

Distribution, spread and habitat preferences of nutria (Myocastor coypus) invading the lower Nakdong River, South Korea

“…(1) location in the river system (Guichón et al 2003), (2) food availability (Carter et al 1999), (3) riparian buffer zone (Gosling et al 1980), (4) levee type (Corriale et al 2006), (5) water flow rate (Atwood 1950;Ehrlich 1962), (6) sand dune occurrence (Corriale et al 2006;Meyer 2006), and (7) sheltering area at the edge of the water Taylor et al 1997;Guichón et al 2003;Corriale et al 2006). The relationship between these habitat characteristics and nutria occurrence (i.e.…”

Effects of mud fiddler crabs (Uca pugnax) on the recruitment of halophyte seedlings in salt marsh dieback areas of Cape Cod (Massachusetts, USA)

“…The effects of soil-disturbing fauna on plant communities, both positive and negative, have been well documented in a wide variety of ecosystems (e.g., Swihart andPicone 1991, Laundre´1998;Carter et al 1999;Rudnick et al 2005). In coastal wetlands, there are many different kinds of burrowing animals, including several species of crabs.…”

Ecological Dynamics II: The Influences of Vertebrate Herbivory on Ecological Dynamics in Wetland Ecosystems

“…Its burrowing activities, however, threaten dykes, and the strong impact of coypu on vegetation is now considered a serious threat to marsh vegetation. Coypu activity that totally removes vegetative cover in 'eat-outs' is probably one of the major reasons for the observed increase in the erosion and loss of coastal marshes in Louisiana, USA (Carter et al 1999). In the United Kingdom, special trapping programmes were ultimately successful in eradicating the coypu.…”