Plants and animals are disappearing at unprecedented rates due to threats caused by human modification and clearing of their habitats. Many governments are now investing in trying to reverse these declines before species are lost.
However, forecasting changes in communities of animals and plants under management is hindered by very little information on individual species’ responses to threats and their mitigation, as well as uncertainty in which species might benefit or suffer under alternative management strategies.
We are slowly learning the effects of some management actions on certain well-studied species. For example, in grazing or cropping landscapes where trees have been cleared, a number of woodland bird species such as the willie wagtail, grey fantail and many honeyeaters will most likely increase in a patch of remnant vegetation if we restore tree cover through revegetation or grazing exclusion.
We also know that other species might decline if their patch of vegetation is changed through restoration, because they prefer the current open conditions to more closed canopy woodland (e.g. the much-loved Bird of the Year, the Australian magpie, and parrots such as the eastern rosella).
Our study is unique in evaluating our predictions five years after management of the three threats; and what we found supported our models. Birds that co-occurred in the threatened landscape were more likely to respond in similar ways (e.g. both species increased when livestock grazing was reduced), and species with more links responded better than those with few links to other species. Birds that avoided one another in the threatened landscape were more likely to respond to management in different ways (e.g. one species increased when livestock were removed from a vegetation patch whilst the other declined).
Despite overwhelming evidence that most ecosystems are exposed to multiple co-occurring threats that need to be managed simultaneously to recover species, no studies have attempted to predict the likely outcomes of mitigating multiple threats on the entire community of species, information that is vital to effective management decisions.
Our paper shows that analyses of co-occurrence networks are crucial for informing decisions about threat management when there are uncertainties about which species might benefit versus suffer from a given action and not enough time or money to learn about every individual species’ response. By thinking not only about individual species but about how they share space and resources with others, we can ensure that management actions are chosen that benefit the most vulnerable species, and avoid actions that might lead to unintended declines.
Created with images by leardstateforest - "Aerials of Leard State Forest and surrounds." • AdaMacey - "Barbs gettin' rusty..." • PaulBalfe - "Little Grey Fantail" • sandid - "lewin's honeyeater meliphaga lewinii bird" • sandid - "magpie australian magpie hungry" • sharp_pics - "Eastern rosella" • recoverling - "qld deforestation" • sussexbirder - "Brown Treecreeper (Climacteris picumnus)" • leardstateforest - "Aerials of Leard State Forest and surrounds." • James Niland - "Noisy Miner Portrait" • blachswan - "Eastern Rosella"