Download Introduction to Overexploitation - Introduction to Conservation Biology - Lecture Slides and more Slides Biology in PDF only on Docsity! Overexploitation Docsity.com N Time Exponential growth ∆N ∆t = r • N Occurs when growth rate is proportional to population size; Requires unlimited resources Population Dynamics Docsity.com Yield (Y) N or overexploitation (overharvesting) Sustainable yield K Rate of net production of new individuals Exploitation (harvesting) Population Dynamics & Maximum Sustainable Yield (MSY) ∆N ∆t or ∆N ∆t = Docsity.com N K ½ K MSY Sustainable yield Constant quota exploitation Yield (Y) Population Dynamics & Maximum Sustainable Yield (MSY) Docsity.com N Constant quota exploitation MSY quota Low quota High quota This is very rarely truly sustainable (since it is difficult to obtain demographic information to make the predictions and half of the possible intersections on the curve are unstable) Yield (Y) Population Dynamics & Maximum Sustainable Yield (MSY) Docsity.com N K Zone of Allee Effects b d Population Dynamics & Allee Effects Allee Effects occur when per capita fitness declines as a population becomes smaller or d b ? ? Docsity.com Logging Subsistence hunting Sport hunting Pest management Fishing Shelling Non-timber forest products Trapping Pet trade Examples of Exploitation of Target Species Docsity.com Paleolithic human hunters may have caused the extinction of many species of megafauna (large- bodied birds and mammals) Pleistocene Overkill Hypothesis Pleistocene = 1.8 million to 10,000 yr before present Docsity.com Economic Incentives to Combat Overexploitation e.g., conservation agreement between Conservation International (CI) & Chumnoab Commune, Cambodia Commune members agreed to several specific measures of good land stewardship in their patchwork landscape of agriculture (rice) & protected forests (wildlife & timber) CI agreed to provide economic incentives, including 8 water buffalo after 1 year (5/25/06 – 5/24/07) Threat: overharvesting of wildlife (e.g., crocodiles) & timber Docsity.com Economic Incentives to Combat Overexploitation e.g., conservation agreement between Conservation International (CI) & Chumnoab Commune, Cambodia 12 ha cleared illegally by commune members; after renegotiation, 6 water buffalo were provided by CI Collectively, the commune eagerly entered into new contracts in subsequent years Compliance monitoring conducted by Cambodia Forestry Administration, an independent party Threat: overharvesting of wildlife (e.g., crocodiles) & timber Docsity.com Economic Incentives to Combat Overexploitation e.g., conservation agreement between Tetepare Descendants’ Association (TDA) & villagers in the Solomon Islands Image of leatherback turtle digging a nest from Wikipedia; case study from Ted Groves (UCSD), pers. comm. Villagers agreed to protect sea turtles by reporting to sea turtle monitors Threat: overharvesting leatherback sea turtle females & eggs Villagers & monitors receive compensation upon initial report & upon successful hatching So successful that TDA seeks to build an endowment to fund future payments Docsity.com
