Win-Win Ecology – The Good News

Most of us know that humans have largely transformed this planet, and that species and their habitats are being lost at an alarming rate. However, there are National Parks and reserves, and international efforts to protect more of the remaining natural environments on land and in the sea – surely that should take care of the problem?

The unfortunate answer is that it cannot. As important and wonderful as these conservation efforts are, they will not protect the majority of species left on earth. But there is some good news – we can adapt our urban, suburban and agricultural environments to protect many of these species, and we can make a difference. We can become practitioners of what the ecologist Michael L. Rosenzweig calls “Reconciliation Ecology” in his book “Win-Win Ecology”. This book fundamentally changed the way I think about our Noordhoek environment, and gave me new optimism. So let’s take a look at why we need to put these ideas into practice.

Why are reserves not enough?

Biologists have known for a long time that the number of species that an area can support is related to the size of that area: in general, the bigger the area, the more species there are. In fact, this relationship can be quantified, and it is exponential. Technically, that means that it is a log-log relationship, but anyone interested in those details needs to read Rosenzweig’s book. The important point is simply that if we want to preserve all the species this earth holds, then we need to preserve the whole of the earth’s surface in a natural state. Well, it’s far too late for that! Most estimates agree that at the moment less than 5% of terrestrial environments are in their natural state! That’s right – not 50%, or even 20%, but less than 5%.

So, why can’t we cram all the animals and plants into what’s left, and look after that very carefully? It turns out that things are not that simple – species are constantly evolving and becoming extinct, and those processes depend on large populations that are contiguous (meet up at the edges). Isolated bits of natural land will tend to lose species faster than new species evolve, especially when natural disasters (like droughts, fires, floods, or unusually cold or warm weather) strike. Again, Rosenzweig describes these processes simply but in detail. We are losing species fast, and only a new approach can slow down the rate of loss.

What can we do?

The new approach is what Rosenzweig calls Reconciliation Ecology (or in trendy terms, Win-Win Ecology). Basically, this consists of deliberately modifying the human environment to create habitats for as many species as possible. In other words, we need to create habitats within our urban, suburban, agricultural and rural environments that will make the indigenous plants and animals welcome – they will do the rest.

In Noordhoek, this is even more important, because our valley forms a break in the Cape Peninsula mountain chain. We can either build a unfriendly barrier to natural life: a sterile suburban “no-creature’s land” of impermeable concrete walls, cropped lawns and insecticide-poisoned beds of exotic flowers, or a diverse, species-rich series of habitats that support indigenous birds, rodents, insects, and plants, forming a link between the mountains to the north of us and the wetlands and mountains to the south.

In practical terms, there are many things that each land-occupier can do.

Build only permeable barriers. If you have to have fences, use material with gaps and holes in it, like vertical steel railings, or large-mesh game fencing. For greater security, these can be planted with thorny hedges (far more difficult to get over than a concrete wall!).

A wall is an impermeable barrier to small animals, although it may give some (illusion of?) security.

A wooden fence with gaps is pleasing to the eye and allows insects and small animals to pass through.

Paddock-style fencing may be too permeable for some, but with a spiky hedge or game-fencing, it is reasonably secure and no barrier to small life.

Do not use insecticides or herbicides. These will kill far more “friendly” natural species than the one “pest” they are aimed at, and can disrupt even a garden ecosystem and make future problems worse. A diverse garden will seldom suffer infestations of pests, and when natural pests do proliferate, their natural enemies will also do so, and in time bring them under control. A good example of this was the massive outbreak of milkwood-eating caterpillars in parts of Noordhoek in 2005 (see our story “The Milkwood Eaters”)

Grow a variety of indigenous plants. Get advice from local experts or your nursery, and plant a mixture of water-wise species that provides berries for birds, flowers for nectar-feeders (birds and insects), and a variety of habitats for birds and insects.

Avoid alien pest plants or those with the potential to become pests. These will seed themselves in nearby natural land and replace a diverse natural vegetation that contains many habitats and food sources with one-species thickets that support very few species of plants or animals.

A final thought

We can do something – we are shaping most of the world – let’s shape it to protect natural habitats and create habitats that are as natural as possible!

Rob Anderson, March 2007.

Reference

Michael L Rosenzweig, 2002. Win-Win Ecology. How the Earth’s Species Can Survive in the Midst of Human Enterprise. Oxford University Press, 211 pp.

Further information

Picker. M. and Anderson, R.J. Milkwood forests under attack by gypsy moths. Veld and Flora, June 2006, pp. 89-91.

Information on SA insects

Picker, M.D., Griffiths,C. and Weaving, A. 2002. Field guide to insects of South Africa. Struik, Cape Town.