When a landscape is transformed irrevocably, what replaces it is a novel ecosystem. Examples of novel ecosystems are suburbs built over grasslands, wheatfields replacing renosterveld, sugarcane farms where there used to be coastal forest, etc, etc. Dams, from mega dams to farm dams, create freshwater habitat in areas that were dry. These are novel habitats. Pine plantations, orchards, vineyards, pastures, cities, … , all represent novel ecosystems.
Development, and also climate change, are going to increase the area which is classified as novel ecosystems.
Novel ecosystems pose ethical dilemmas for conservation. Does a farm dam, which is supporting a diversity of waterbirds and even dragonflies, have value for biodiversity conservation? They were not there before the dam was built. Do the wheatfields of the Overberg region of the Western Cape have biodiversity conservation value? They destroyed a lot of natural habitat, but now support a large fraction of the world population of Blue Cranes. Should biodiversity conservation focus on pristine habitats? Or should we also be focusing on “making the best of a bad job” doing conservation in our suburbs, canalized rivers, golf-courses and sewage works? There are eucalyptus trees at some of the railway stations on the Karoo which are used by roosting Lesser Kestrels. Should we chop the trees down because the are aliens? Or should we protect the trees and declare the railway station precinct to be an area of special biological importance, because of the role it is playing in the conservation of a threatened species?
What seems obvious is that the challenge which novel ecosystems create for conservation biologists, policy makers, landowners and even gardeners.is not a choice between pristine ecosystems and novel ecosystems. Somehow we have to do both.
Here is a blog on a totally messed up section of a river in Cape Town. The river was straight-jacketed into a concrete canal. The river fought back. This is a great but inevitably transient example of a novel ecosystem. Transient, because the City can return at any moment and return this ecosystem to a concrete shell.
There is a growing number of scientific papers about novel ecosystems. The following paper is a useful point of entry if you want to find out more: Novel ecosystems in the urban-industrial landscape – Interesting aspects of environmental knowledge requiring broadening: A review.