Environmental Dependency of Inbreeding Depression: Implications for Conservation Biology

Inbreeding depression is environmentally dependent, such that a population may suffer from inbreeding depression in one environment but not another. We examined the phenotypic responses of 35 inbred ( F = 0.672) lineages of the red flour beetle Tribolium castaneum in two different climatic environments. We found a significant environmental effect on males but not females. More important, we found that the rank fitness order of lineages differs between environments; lineages of high fitness in one environment may have low fitness in another environment. This change in rank is evident in a significant genotype-by-environment interaction for inbreeding depression for both females and males. These results suggest that even if we know the average environmental effect of inbreeding depression in a population, for any particular lineage measurements of inbreeding depression in one environment may not predict the level of inbreeding depression in another environment. Conservation biologists need to be aware of the environmental dependency of inbreeding depression when planning wildlife refuges or captive propagation programs for small populations. Ideally, captive propagation programs should maintain separate lineages for release efforts. Refuge design programs should consider maintaining a range of habitat types.     

Conservation Biology and Real-World Conservation

Abstract:  In the 20 years since Conservation Biology was launched with the aim of disseminating scientific knowledge to help conserve biodiversity and the natural world, our discipline has hugely influenced the practice of conservation. But we have had less impact outside the profession itself, and we have not transformed that practice into an enterprise large enough to achieve our conservation goals. As we look to the next 20 years, we need to become more relevant and important to the societies in which we live. To do so, the discipline of conservation biology must generate answers even when full scientific knowledge is lacking, structure scientific research around polices and debates that influence what we value as conservationists, go beyond the certitude of the biological sciences into the more contextual debates of the social sciences, engage scientifically with human-dominated landscapes, and address the question of how conservation can contribute to the improvement of human livelihoods and the quality of human life.     

Gaia's Handmaidens: the Orlog Model for Conservation Biology

Abstract:  The Gaia hypothesis, which proposes that Earth's biota and material environment form a self-regulating system, has been influential in conservation biology, but it has not translated into specific guidelines. Proponents of phylogenetics and ecology often claim primacy over the foundations of conservation biology, a debate that has deep roots in philosophy and science. A more recent claim is that conservation efforts should protect evolutionary processes that will allow diversification. Phylogenetics, ecology, and evolution all have legitimate roles in conservation, when viewed in a temporal perspective. Phylogenetic studies identify the bioheritage of past species radiations, ecology preserves the life-support systems for these lineages in the present, and evolutionary processes allow adaptation of these lineages to novel challenges in the future. The concept of temporal domains in conservation (past, present, future) has an appropriate metaphor in the Norse worldview known as the Orlog. In this body of mythology, three sisters tend the tree of life and fend off a dragon gnawing at the roots. The names of these sisters, Urd, Verdandi, and Skuld, translate to Past, Present, and Future. In Viking mythology, the threads of life cannot persist without the cooperation of these sisters. In the science of conservation biology, they represent the handmaidens of Gaia–three scientific disciplines that can succeed only with a spirit of familial cooperation.     

A Science for Survival: Values and Conservation Biology

Practice of conservation biology that does not actively and continuously question the values that shape it is self-defeating: Conservation biology is inescapably normative. Advocacy for the preservation of biodiversity is part of the scientific practice of conservation biology. If the editorial policy of or the publications in Conservation Biology direct the discipline toward an "objective, value-free" approach, then they do not educate and transform society but rather narrow the focus to the "object of knowledge" (be this species, gene pools, landscapes, or ecosystems). To pretend that the acquisition of "positive knowledge" alone will avert mass extinctions is misguided. Conservation biologists should reflect on the constitutive values (especially contextual, but also methodological and bias) underlying their research programs and policy recommendations. Such reflection is itself an inherent element of scientific objectivity and takes into account the social nature of scientific knowledge. Without openly acknowledging such a perspective, conservation biology could become merely a subdiscipline of biology, intellectually and functionally sterile and incapable of averting an anthropogenic mass extinction.     

Long-Term Ecosystem Dynamics in the Serengeti: Lessons for Conservation

Abstract:  Data from long-term ecological studies further understanding of ecosystem dynamics and can guide evidence-based management. In a quasi-natural experiment we examined long-term monitoring data on different components of the Serengeti-Mara Ecosystem to trace the effects of disturbances and thus to elucidate cause-and-effect connections between them. The long-term data illustrated the role of food limitation in population regulation in mammals, particularly in migratory wildebeest and nonmigratory buffalo. Predation limited populations of smaller resident ungulates and small carnivores. Abiotic events, such as droughts and floods, created disturbances that affected survivorship of ungulates and birds. Such disturbances showed feedbacks between biotic and abiotic realms. Interactions between elephants and their food allowed savanna and grassland communities to co-occur. With increased woodland vegetation, predators' capture of prey increased. Anthropogenic disturbances had direct (hunting) and indirect (transfer of disease to wildlife) effects. Slow and rapid changes and multiple ecosystem states became apparent only over several decades and involved events at different spatial scales. Conservation efforts should accommodate both infrequent and unpredictable events and long-term trends. Management should plan on the time scale of those events and should not aim to maintain the status quo. Systems can be self-regulating through food availability and predator-prey interactions; thus, culling may not be required. Ecosystems can occur in multiple states; thus, there may be no a priori need to maintain one natural state. Finally, conservation efforts outside protected areas must distinguish between natural change and direct human-induced change. Protected areas can act as ecological baselines in which human-induced change is kept to a minimum     

Exotic Organisms: A Dilemma for Conservation Biology

Abstract: Human-induced problems in resource conservation fall into three categories: (1) inappropriate resource use, (2) pollution, and (3) exotic organisms. Problems of resource use and pollution are correctable; exotic organisms are frequently permanent and may be the most pervasive influence affecting biodiversity in many systems, particularly on oceanic islands. Invasive exotic organisms often have effects far in excess of what might be predicted by equilibrium island biogeographic theory; a single exotic species may cause numerous extinctions in addition to altering the physical environment. Exotic organisms frequently cause environmental crises. In such crises, calls for more research are commonplace, but research results may be an unaffordable luxury, providing information only for the eulogy. Programs to eradicate exotic organisms provide an opportunity to combine good science and good conservation into functioning conservation biology.