Conduct scientific studies on large-bodied animals and their interactions with other species, including humans, providing high-valued knowledge for management and conservation.
Conduct scientific studies on large-bodied animals and their interactions with other species, including humans, providing high-valued knowledge for management and conservation.
WHY STUDY LARGE ANIMAL ECOLOGY?
LARGE ANIMALS ARE BOTH UNIQUE AND IMPORTANT
Different selective forces may have favored large body size in animals: to be large pays off in interference competition, in predation for both the predator and the prey, or in heat conservation in warm-blooded species due to a decreased ratio of body surface to body volume. However, the drawback of being large is the higher energy demand connected with body weight, both to sustain the basal metabolic functions as well as reproduction, locomotion and other activities. Consequently, large-bodied species often roam over larger areas than small-bodied species to ensure access to resources and mates. Many large-bodied species are long-lived and characterized by low reproductive rates and long generation times combined with a higher investment per offspring than small-bodied species.
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Due to their high energy demand, large-bodied species are often very influential in an ecosystem. They may have key roles in species communities by e.g. consuming an essential part of the net production at the next lower trophic level, which again may lead to cascading effects at lower trophic levels. This applies to top predators as well as large herbivores. However, their impact in ecosystems is often in conflict with human interests.
HUMANS ARE THE MOST INFLUENTIAL LARGE ANIMALS
As human beings, we represent the most influential large-bodied species, not only because we make up 36% of all mammalian biomass on Earth, but also because we harvest and exploit other species on all trophic levels, alter natural habitats and cause climate change. We have eradicated or reduced other large-bodied species in most of the world because we perceived them as a threat to human safety, competitors for livestock production and harvest of game. We have over-harvested populations of large-bodied species in our need for food, pelts and trophies. Our need for space and transportation has led to habitat loss and fragmentation, with negative impacts disproportionately affecting wide-ranging, large-bodied species. Pollution leads to accumulation of toxic substances in long-lived species, particularly for those at the top of the food chain. Not surprisingly, large-bodied wild mammals have a higher extinction risk than smaller mammalian species.
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Humans impact ecosystems also indirectly through livestock production. Today, livestock, dominated by cattle, makes up close to 60% of all mammalian biomass on Earth. These large-bodied domestic grazers appropriate a large proportion of all net primary production consumed by terrestrial herbivores and have altered the Earth’s terrestrial ecosystems, first from highly structured forests to nutrient-poor, species-rich meadows, and in recent times to nutrient-rich, species-poor grasslands. If kept on uncultivated lands, domestic species may interact with wild species and conflict with human interests, such as forestry or carnivore conservation.
LARGE ANIMALS ARE AT RISK
In light of the ever-growing human need for natural resources and global warming, there is an immediate need for management measures that can balance human needs and species conservation. To be successful, management actions should be knowledge-based and adaptive, for example, offer an effective framework to manage resources in the face of uncertainty. This learning process involves assessing the impact of management measures, searching for and systematically testing new and alternative methods, and adjusting measures based on new knowledge and/or changing circumstances. Applied to large-bodied species, this implies continuous monitoring of the populations in question as well as related human-wildlife conflicts. It also requires up-to-date knowledge on the ecology of the species or populations in question, on factors that affect population dynamics and viability, on spatial and temporal variation of these factors, and direct and indirect effects of the species on other species.