|
|
| Invasive Species 
What They Are and Why You Should Care Invasive species are plants and animals that are not native to an area. Often brought in without thought to their potential harmful effects, invasions have begun innocently through boat transfers, aquaria, stowaways in produce and other shipments and other methods. Invasive species can alter both the biological and physical habitats, driving out native species and changing the ability of an area to support its original plants, animals and birds by altering the feeding, reproductive and other habitats required by native organisms. Scientific statement Human activities have long been shown to be agents of dramatic alteration of the distribution of earth’s biota (Elton 1958; Drake et al. 1989; Williamson 1996; Corn et al. 1999). Estuaries and bays are particularly vulnerable to invasion because of the abundance and variety of non-native exposures by humans using these environments. For example, entire planktonic assemblages can be moved down a coastline, among estuaries and even across oceans in the ballast water of international vessels (Carlton 1987; Carlton and Geller 1993). Vessel hulls can also tranport sessile organisms. Further, many adult invaders have been stocked and/or accidentally released by people in the aquarium, aquaculture and seafood industries. Invasions by non-native species are recognized as a leading contributor to global biodiversity loss (Gophen et al. 1995; Vitousek et al. 1997; Pimm 1987; ).Hundreds of non-native aquatic species have become established in U.S. estuaries and the numbers are steadily increasing (Cohen and Carlton 1998; Ruiz et al. 2000). These non-native species alter the composition of estuarine species and potentially affect the behavior, distribution, and trophic interactions of native species. Some non-native species alter the physical characteristics of estuarine habitats changing population, community, and ecosystem processes in estuaries and bays (Ruiz et al. 1997; Grosholz 2002). While the destructive effects of non-native species are now widely known (Corn et al. 1999; Carlton 2001), the patterns of invasion in U.S. estuaries are still not well understood. Experts identify a vital need to initiate “standardized ecological surveys of non-native species across major regions of the U.S.” (Ruiz et al. 2000). | |
|