tailieunhanh - WILDLIFE SCIENCE: LINKING ECOLOGICAL THEORY AND MANAGEMENT APPLICATIONS - CHAPTER 9

Sự đa dạng của các hệ thống sinh thái từ lâu đã nghĩ rằng để tăng sự ổn định của các hệ thống. Các quan sát và lý luận trực quan Odum (1953), MacArthur (1955), Elton (1958), và các Các nhà sinh thái học sớm chỉ ra rằng các cộng đồng phức tạp kháng hoặc chống chịu được các nhiễu loạn, có nghĩa là trong bản chất với các loài tương tác hơn, sinh khối, thành phần, và năng suất của một cộng đồng ít biến hơn. Điều này có vẻ hợp lý trong một hệ thống rất đơn giản (nondiverse) dựa tất cả các. | 9 Seeing the World through the Nose of a Bear Diversity of Foods Fosters Behavioral and Demographic Stability David L. Garshelis and Karen V. Noyce CONTENTS Relevant Life History Characteristics of Black Bears. 141 Bear Management in Minnesota. 142 Data on Minnesota Bears . 143 Bear Diet Foraging Strategies and Habitat Use. 144 Temporal and Spatial Variation in Food Production. 146 Variation in Movements. 148 Variation in Nuisance Activity. 149 Variation in Cub Production . 150 Variation in Harvest and Harvest Composition. 153 Variation in Population Size and Composition. 155 Causes of Bias in Population Estimates. 155 Management Implications. 157 Postscript Diversity versus Key Foods. 159 Acknowledgments. 160 References. 160 Diversity of ecological systems has long been thought to increase the stability of those systems. Observations and intuitive reasoning by Odum 1953 MacArthur 1955 Elton 1958 and other early ecologists indicated that complex communities were more resistant or resilient to perturbations meaning in essence that with more interacting species the biomass composition and productivity of a community were less variable. This seemed logical in that a very simple nondiverse system relies on all parts functioning normally a disturbance to one key element species or group of species is likely to upset the balance and function of many other components. Diverse systems are more failsafe because of internal redundancy or many species serving similar roles thus providing insurance 139 2008 by Taylor Francis Group LLC 140 Wildlife Science Linking Ecological Theory and Management Applications against a widespread catastrophe unless all species in a certain guild or functional type Hooper et al. 2005 react similarly to a perturbation. Moreover unlike simple systems diverse systems have many linkages among species so change in abundance of one species would have less drastic effects on the others. Early computer modeling of ecosystems initiated by May 1973 .