Ch. 18 Study Guide

Ch. 18 Study Guide - Ch 18 Study Guide Exotic Wildlife...

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Ch. 18 Study Guide Exotic Wildlife Exotics are those organisms introduced into places that they have not previously occupied. Exotics range from human comensals to serious pests that have directly or indirectly affected wildlife to valued additions to our native faunas. 1. Some examples of exotics 1. rats, fire ants, starlings, brown tree snake, European mute swans but also, ring-necked pheasant, chukar, sika deer… 2. Mongoose - 1. Inadvertent introduction of another exotic, the Old World rat ( Rattus rattus ) a human comensal, led to a major ecological mistake involving the mongoose. 2. In an attempt to control rat populations on Caribbean Islands and Hawaii, mongoose were released with the intent that they control snakes and rats. However, snakes were only partially controlled by mongoose and after depleting the more easily available rats in sugar cane fields the mongooses began to prey on native mammals and ground nesting birds. Within 20 years of its introduction into the Caribbean, the mongoose was considered the worst of all the pests. 3. It is currently illegal to bring even 1 mongoose into the continental U.S. . 2. The case for exotic game 1. major impetus for introductions in N.A. came after World War II 1. hunting license sales soared with returning soldiers 2. soldier-sportsmen added interest in exotic game with the tales/experience they had with animals encountered on foreign soil 2. Financial rewards for exotic game 1. in 1977, Trophy class exotics stocked on ranches provided gross profits to ranch entrepreneurs of 40-80%. However, the average return on investment was < 2% if land costs (the cost of using the land and the costs of damage/degradation/ restoration to the land were included. 2. Addition of exotics increased returns by 20% (without land costs included) where native wildlife was also hunted for economic gains 3. Works on Private lands only 3. conditions under which one might consider introduction of exotic game species 1. natural habitats lack any suitable game species 2. natural habitats have a limited abundance of native game 3. modified habitats non longer producing sufficient native game and/ or those habitats where restoration is not practical 4. The "vacant niche"
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1. Pleistocene extinctions of N.A. fauna may have left resources
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Ch. 18 Study Guide - Ch 18 Study Guide Exotic Wildlife...

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