This chapter explores different conservation strategies and the important debate on the best way to conserve ecosystems. Nature protectionists insist that people-free Protected Areas are the only proven method while social conservationists insist that the sustainable use of wildlife with social justice for local people is the only long-term solution. Evidence shows that five elements need to be present for marine Protected Areas to be effective, including the engagement of local people. Global international conservation has the right priorities, but enacting them is hard; for example, the plan for UK conservation calls for a wildlife-friendly landscape, with a large expansion in reserve area and connectedness, together with more effective management. There is not necessarily any conflict between biodiversity conservation, agricultural production, and human wellbeing. The trick is to find the win-win-win solution.
Conservation, Ecology, and Science
This chapter discusses the relationship between conservation, ecology, and science. The big problem facing human beings, and all other organisms on the planet, is that the ecological footprint of humans—the area of biologically productive land needed per person per year to sustain their lifestyles—exceeds the ability of the Earth to support it. This environmental crisis will drive many species to extinction. The extent to which these extinctions matter depends on what the species actually do in ecosystems. The chapter then looks at the importance of biodiversity. Apart from dealing with living evolving organisms that are individually different, there are other important aspects of ecology (and hence conservation) as a science. Some of these are: that it involves the hierarchical structure of nature; that it involves huge changes of scale; and that there are many different kinds of explanations for the same thing.
Francis Gilbert and Hilary Gilbert
Conservation starts off by looking at conservation, ecology, and science and describing how they relate to each other. It then examines populations and how they may change in relationship to movement and the size of suitable habitat available, covering also processes that lead to extinction. Other topics include interactions among different species and the processes through which ecological communities are created. Ecosystems are treated next with a look at their relationship to human wellbeing. Finally, the text examines different human attitudes towards nature, including those of indigenous people, and different conservation strategies.
Ecosystem Services and Human Wellbeing
This chapter highlights the importance of conservation for human wellbeing. Nature provides us with ecosystem services vital to our health and wellbeing. However, these services have been taken for granted until now. There is a relationship between biodiversity and ecosystem service delivery; loss of biodiversity leads to losses in the ecosystem service, both in its level and its reliability. Traditionally, nature has been valued at zero, hence decision-makers rarely opt for nature conservation rather than using land for other purposes. It is vital that we value ecosystem services correctly and fully so that the real cost of their loss is realized. Often when the full costs and benefits are assessed, nature conservation turns out to be the most cost-effective and valuable option.
Indigenous People and Conservation
This chapter assesses the role of human beings in the environments of yesterday. Since they first evolved, humans have both modified and been part of the environment. Evidence that hunter-gatherers lived 'in harmony with nature' and that urban humans are uniquely destructive is poor. Attitudes towards nature were universally animistic in hunter-gatherers, but changed in urban humans, who usually thought of nature as a threat and as dangerous. In Western thought, the Romantic movement produced the idea of conservation as a way of keeping 'pristine' nature as a spiritual resource for humans. Studies of modern indigenous peoples show that they often have mechanisms for sustaining their environment that can easily be lost when Western-style development arrives.
Interactions Among Species
This chapter evaluates interactions among species. Most species interactions in ecology are between insects and plants. Selection for defence against herbivores has led plants to evolve toxins, while selection for the ability to use a toxic diet has led herbivores to evolve counter-measures, such as P450 detoxification enzymes. This coevolutionary process is a major source of evolutionary change. Meanwhile, top predators can have disproportionate effects (a 'trophic cascade') on the species below them in the food web of their community. The eradication of wolves by humans in Yellowstone National Park had the unintended consequence of preventing tree regeneration. The chapter also looks at indirect interactions via intermediate species. Conservation needs to pay attention to the variety of ways in which such indirect interactions work.
Populations, Patchiness, and Movement
This chapter describes how population sizes change. Understanding the dynamics of populations involves studying the key demographic processes of birth, death, immigration, and emigration. Much of twentieth-century population ecology concentrated on explaining population dynamics of closed populations, using the effects of density on births and deaths, while ignoring movement. The equilibrium theory of island biogeography changed this focus onto the study of movement as a key determinant of species richness. This focus was then transferred into the idea of the metapopulation, a set of extinction-prone populations on patches kept going by the movement of individuals. Natural landscapes consist of many patches of suitable habitat in a sea of unsuitable habitat. Movement across such landscapes is an important element in the population dynamics of many organisms.
Rarity and Extinction
This chapter examines the consequences of changes in the size of a patch of suitable habitat. Reductions in island or habitat area lead to extinction of some of the populations because of the reduced resources and increased isolation. Meanwhile, habitat fragmentation leads to an extinction debt because it takes time for populations to die out. Creating corridors between isolated patches can help prevent some extinctions, but they cannot abolish them entirely. Setting aside nature reserves for conservation is obviously a good thing to do, but it will also not be enough as the reserves become isolated patches of natural habitat in a sea of man-made agricultural or urban landscapes. Ultimately, a landscape approach to conservation is needed for it to be successful.
What Processes Create Ecological Communities?
This chapter focuses on four processes at work in ecological communities. These are selective forces (competition, predation, and coevolution) that modify the characteristics of populations and species, and/or determine their presence in a community; ecological drift, i.e. random chance that affects small populations in particular, that might lead to extinction or immigration events; speciation; and dispersal. On the large scale, the relative importance of these processes is not the same as on the small scale. The species richness of local communities depends on large-scale species richness via the processes of dispersal, and abiotic and biotic filtering. The chapter then considers the idea of the 'balance of Nature'.