PARASITES AS THREATS TO BIODIVERSITY IN SHRINKING ECOSYSTEMS

Shrinking ecosystems concentrate both individuals and species into res tricted areas, promoting transmission and exchange of parasites. Fragm entation increases edge and brings an influx of new species into the d isturbed or agricultural habitats between fragments, introducing new p arasites and possibly leading to the development of new and more patho genic strains of parasite. Environmental contaminants act as stressors , and may compromise immune systems. Global climate changes challenge the adaptability of organisms, and may allow the invasion of new paras ites. Because each of these effects increases the potential for parasi tes to become pathogenic, the importance of disease is expected to inc rease in shrinking ecosystems, with the emergence of new diseases and increasing numbers of epidemics. Increased pathogenicity of generalist parasites may pose a threat to species with restricted distributions or small populations.