Predators

Natural Resources Management
01/29/97
Predators and Ecosystem Management

Predators have an everlasting effect on different kinds of ecosystems. They influence there ecosystems by controlling the abundance of lower species certain habitats. In this article, "Predators and Ecosystem Management" by (James A. Estes). He explains results of case studies that indicate important ecological roles for predators in a huge coastal ecosystem. The main challenge in this article is to determine if there are recurrent patterns else where in nature and to also understand when and where they occur.
The author gives his perspective on predators and the coastal ecosystems by giving us a living example, the sea otter and the kelp forests. The relation between the sea otters and the kelp-forests was provided because of a accident of history, the over-exploitation of sea otters in the Pacific maritime fur trade. The study compared areas where sea otters were abundant with nearby areas to area's where they're almost extinct. By doing this comparison of the sea otters coastal system it was possible to gain much insight into the sea otter ecological role in kelp-forest ecosystem.


Over the years it's been possible for us to observe the kelp-forest ecosystem over-time, thanks to the massive growth of the sea otters population we observed the change from otter-free to otter-dominated.
This article relates to many aspects of our textbook. On page 89 in chapter 5 the text explains what an ecosystem is, defined by the book, it's a community of species interacting with one another where there is a non-living environment. In this case the otter and kelp-forests ecosystems a coastal ecosystem. As mentioned in the book, the food chain is involved in the sequence of events with the organism that are the source of the food. In a survey of coastal habitats in many areas of the North Pacific Ocean have revealed that kelp forests usually are extensively deforested where sea otters are absent whereas this condition is rare where occur ( Estes and Duggins 1995).
All ecosystem management has recently emerged as the main way of conversation in wildlife biology and as an alternative to the traditional approach of species-level management. This kind of approach, (1) has involved many resource-management agencies because of the growth or disappearance of their habitats, and (2) the amount of species is great and the time is too short to conserve these species in any other way.






Bibliography
1) Estes, James A.,1996,24(s): Predator and ecosystem management,
Wildlife Society Bulletin, Ca, pg.390-396.
2) Miller, Tyler G.,1996,Living In The Environnment,
Wadsworth Publishing Company,Ca. pg.122,105-107.