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Conclusions Much work needs to be done before a unified approach to conservation biology emerges. Several issues remain unresolved, including scale. An anthropocentric bias towards small spatial scale was illustrated by a survey (Karieva and Anderson 1988) in which 80 percent of experimental community studies were done in areas -9 ft' (1 ml). Some ecologists claim that the processes affected by habitat fragmentation on small spatial scales are similarly affected at large spatial scales. Ims (1990) and Stenseth (1990) suggested that small mammals in small-scale fragmented landscapes can serve as "empirical model systems" for larger mammals living in areas frag- mented by human activity. Similarly, J. A. Wiens (personal communication: 1991) believes that it might be possible to use information obtained at a micro-landscape level (e.g., beetles on a lawn) to make predictions about larger scales (e.g., elephants on the Serengeti). To extrapolate processes that occur at a microscale to a macroscale phenomena is appealing because the smaller the scale, the more amenable the system is to experimental manipulation. However, making generalizations about population dynamics from small to large landscapes may be possible only if ecological processes scale monotonically with area. The complexity of biotic and abiotic interactions increases with area so that a straightforward relationship between small and large scale ecological processes is unlikely. Another major area of contention is the relative role of genetic and demographic factors in causing population extinctions. The "50/500" rule, which has been dis- puted (Simberloff 1988), focuses on the relationship between genetic stochasticity and population extinction. An effective population size of 50 results in inbreeding depression (a short-term effect), whereas 500 results in genetic drift and a loss of genetic variation (a long-term effect). In both cases there would be a high probability of population extinction, particularly in a changing environment. However, Lande (1988:1,455) concludes from theoretical and empirical examples "that demography is usually of more immediate importance than population genetics in determining the minimum viable sizes of wild populations." Nevertheless, Lande (1988) suggests that future conservation plans include integration of ecology and population genetics. An understanding of the ecological genetics of threatened and endangered species in fragmented habitats may be the only hope for species' survival. A fertile area for future research is population persistence in the context of source/ sink dynamics. Species live in a heterogenous landscape with subpopulations oc- curring on patches of varying quality. Habitat fragmentation due to human disturbance has greatly contributed to this heterogeneity. Detailed information on movements between semi-isolated refuges and the manner in which corridors facilitate this move- ment is needed. Information about the mating success of individuals after they immigrate to a new patch can be obtained with recent advances in radiotelemetry and DNA fingerprinting. As wildlife conservation increases in scope and sophistication, ecological theory will be needed in conservation planning and management policy. The development of relevant theory has been rapid, despite the complexity of the questions addressed. The concepts of minimum viable population and population vulnerability analysis (Gilpin and Soule 1986) have provided a valuable heuristic tool: small populations are vulnerable, and very small ones may quickly succumb to stochastic processes. However, a more fundamental issue is how to keep populations and whole species from falling below a critical size. Since nearly all species exist as several populations, 260 ? Trans. 571h N. A. Wildl. & Nat. Res. Conf. (1992)