Conservation biology

4th in a series on ecological science

Conservation is a political movement to place value on nature itself. The value of the food, fibre and fuel that we collect from natural systems is self-evident. It is less clear why we should continue relying on nature rather than further controlling and cultivating our sources of organic matter. Conservation biology is particularly focused on why and how to maintain natural sources of food, fibre and fuel as well as to maintain the experience of being in a landscape or seascape that is beyond our control. The key question in conservation biology is “What is the best use of time and money in maintaining nature?”

Will this species survive?

Much of ecology is focused on individual species. This may be because 1) the species is rare and could vanish forever, 2) it plays a role in supporting other species, or 3) it has played an important cultural role in inspiring people’s lives and ensuring their survival. Population viability analysis estimates the odds of a species’ survival and models the factors that contribute to the continuation of the population in a given area. This technique provides some rigor to the practice of identifying species at risk and, perhaps more promisingly, identifies sensitive life cycle stages and the most effective interventions.

Gordon Court

Restoring the land

Ecological restoration is the process of removing or adding plants and animals at a site in search of a sustainable and diverse balance. Often this involves reinstating a former disturbance regime of burning or flooding to which native species are adapted. Frequently, the focus is on removing invasive species. The techniques for decreasing the population growth rate of invasive species have advanced in recent years, including chemical, biological and genetic methods. Population viability analysis can be used to measure the success of these techniques. Sometimes, the best available outcome is to naturalize the invading species as a part of a sustainable community. Climate change complicates ecological restoration by questioning the nature of sustainability. Ultimately, a restoration project must set a time horizon and a description of the target ecosystem, including anticipated changes from climate.

Fish and trees

The most important ecosystems from a commercial point of view are fisheries and forests. Fisheries management has had many setbacks with almost one third of the world’s fisheries considered to be overfished. The concept of maximum sustainable yield, though based on population modelling, has not been sufficiently broad to consider ecosystem and society effects. Current efforts focus on Marine Spatial Planning, where the incentives to sustain a fishery are front and centre. Forest modelling helps managers to predict the species, growth forms and productivity that will result from harvest and disturbance patterns. Increasingly, climate change is an important part of both fishery and forest management. The fish we catch and the trees we harvest will change with the warmth and moisture of a carbon dioxide rich atmosphere. Oceans and land surfaces help absorb carbon dioxide, even though their ability to do this decreases with increasing temperature.

How can nature help us?

Getting the right balance of wild and cultivated stocks could boil down to a cost-benefit analysis. Are cultivated plants and animals consistently more productive than those produced by nature? Do we properly value the services that nature provides? What would it cost to replace these services with industrial processes? The study of ecosystem services identifies four kinds of service to society:

• Provisioning,including non-cultural commodities that can be sold (e.g.food or pharmaceuticals)

• Regulating, including the moderation of climate, maintenance of air and water quality and disease control

• Cultural, including recreational, cultural and spiritual experiences

• Supporting, including nutrient cycling, soil formation and other services that support the other services but have a significant lag time before they are appreciated by humans.

Models that look at the strength of different services and the trade-offs between them have been developed in different ecosystems. In some cases, there are synergies that allow multiple services to be offered without diminishing the others. Apart from the market value of provisions and the value of local tourism, most of these services are not valued as part of the economy. The danger for most ecosystems is that a Maximum Sustainable Yield approach is adopted without a full apprecation of what it takes to sustain a grove of plants or a population of animals.

A theory of conservation?

Though science has brought increasingly precise data and more discriminating methods to bear on the problem of getting good value from less developed lands and oceans, ecology has not been able to halt biodiversity loss. There is good experimental evidence that more species provide more stable returns in a variable environment. This work on biomass production needs to be replicated in circumstances that test for a net societal return on relying on nature. Nevertheless, the value of wilderness calls out to us as we seek increasing productivity and reliability in our day-to-day life. Ecology will be ready whenever our humility allows us to seek out a lifestyle that is more in-tune with a greater whole.