Ch4b: Overexploitation, Exotic Species, and Disease Species may be threatened even when habitat is intact Overexploitation is driven by globalization & technology Exotic species & diseases are widespreadI. Overexploitation A. What is it?1. overharvesting species2. threatens endangered vertebrates B. Humans are ecologically efficient predators1. traditional societies2. globalization of markets 3. pets, décor, ornamentals 4. technology C. Particularly evident in oceans1. many animals killed as “bycatch”2. maximum sustainable yields may be unrealistic3. overfished marine organisms 1946 –1974 -- 1986 –D. Solutions?1. regulations & CITES 2. national parks & nature reserves3. link conservation & local economies.II. Exotic speciesA. Introduced accidentally or deliberately1. desirable traits2. repeat offenders:3. most introductions are not successful4. few exotics will harm their new environ.B. Introduction facilitated by11. loss of density-dependent factors 2. human altered environ. 3. “weedy” traitsC. Impacts on native biota?1. competition 2. predation3. environmental degradationD. Endangered species in foreign landsE. Natives may become pests F. Few places free of exoticsG. Islands are particularly vulnerableIII. Spread of disease viaA. CrowdingB. Poor health from malnourishmentC. Contact with domestic animalsD. Human travelE. Global climate