Endangered Species and Populations

摘要: Publisher Summary One can define an endangered species based solely on demographic characteristics; i.e., the abundance of is so low or declining precipitously range has retracted greatly that in danger becoming extinct. Note while may be synonymous with a taxonomic species, it also defined as distinct population segmentof species. An alternate approach to consider because threats could lead its extinction. Ultimately, what makes some marked change itself ecosystem (e.g., increased exploitation, loss habitats, etc.). Many, if not most, marine mammal considered being at risk extinction reached this situation human activity (i.e., harvesting). Only recent decades have humans affected habitat sufficiently place risk. These more impacts now extinction, even those formerly due harvesting. Various aspects demography contribute their vulnerability. By beginning twentieth century, many populations had perilously levels.