. Proceedings of the Symposium on Management of Forest and Range Habitats for Nongame Birds, May 6-9, 1975, Tucson, Arizona. Birds Conservation Congresses; Birds Habitat Congresses; Range management Congresses; Wildlife habitat improvement Congresses. GENERAL CONCEPTS Success ion "Ecological succession" or "ecosystem I development": (1) is "an orderly process of community development that involves changes in species structure and community processes with time; it is reasonably directional and therefore predictable, (2) results from modifications of the physical environ
. Proceedings of the Symposium on Management of Forest and Range Habitats for Nongame Birds, May 6-9, 1975, Tucson, Arizona. Birds Conservation Congresses; Birds Habitat Congresses; Range management Congresses; Wildlife habitat improvement Congresses. GENERAL CONCEPTS Success ion "Ecological succession" or "ecosystem I development": (1) is "an orderly process of community development that involves changes in species structure and community processes with time; it is reasonably directional and therefore predictable, (2) results from modifications of the physical environment by I the , (3) culminates in a stabilized ecosystem in which maximum and symbiotic function between organisms are maintained per unit of available energy flow " (Odum 1971). Odum (1969) discusses theoretical trends that can be expected in succession. The most important trends for our consideration are: (1) variety component of species diversity increases number of species increases, (2) equitability component of species diver- sity increases there tends to be a more even division in numbers between individuals of the various organisms in the community, (3) stratification and spatial heterogenity increases more niches become available, (4) niche specialization increases, (5) size of organisms increases,(6) biomass increases, and (7) gross production/community respira- tion (P/R ratio) decreases and approaches one. All of the above results in the complication of food webs and an increase in stability in the system ('De Angelis 1975). There is an inherent conflict in these trends, and our desire to manage avian popu- lations. By necessity most avian management has been incidental to other aims such as timber or pulpwood production. As an ecosystem matures P/R decreases. In other words, no new net biomass is added. Therefore, harvesting will tend to be accomplished when the net in- crement of biomass increase begins to decrease (fig.
Size: 1860px × 1344px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorunitedstatesforestservice, bookcentury1900, bookpublis
