What happens to the wildlife in patches of native vegetation when the surrounding agricultural landscape is converted from open grazed land to closed pine plantation forest? This is far from being an academic question as this situation is increasingly common as plantations are often established on cultivated or grazed land.
Alessio Mortelliti and colleagues conducted a large-scale (30 km2), long-term (14 years) fully controlled and replicated (111 sites) ‘natural experiment’ in south-eastern Australia to answer this question. The study focused on the effects of changes occurring in the agricultural matrix on mammals which inhabit patches of native eucalypt woodland.
They found that none of the five target species in their study responded negatively to pine plantation establishment. For three species (the sugar glider Petaurus breviceps, the red necked wallaby Macropus rufogriseus and the swamp wallaby Wallabia bicolor) the response to plantation establishment was positive (ie, increase in colonisation/patch use in sites surrounded by pines) whereas the two possums (the common ringtail possum Pseudocheirus peregrinus and the common brushtail possum Trichosurus vulpecula) were positively affected by the amount of native tree cover surrounding sites, rather than pine plantation establishment.
The researchers believe there are two strong implications arising from these results. 1) The conservation of agricultural land to pine plantations will not affect the mammalian species they looked at negatively; rather, it may facilitate colonisation of remnant patches of native vegetation by some species. 2) These findings underscore the critical importance of preserving remnant native vegetation within plantations, as it may decrease the risk of local extinction for some species or facilitate the colonisation of new sites for others. Thus, retention of patches of remnant native vegetation should be part of the design of future plantations.
Mortelliti A, M Crane, S Okada & DB Lindenmayer (2015). Marsupial response to matrix conversion: Results of a large-scale long-term ‘natural experiment’ in Australia. Biological Conservation 191: 60-66. http://www.sciencedirect.com/science/article/pii/S0006320715002384
Note: The site where this data was collected, Nanangroe, was also used for a study on the impact of pine plantations on birdlife. This was discussed in Decision Point #91.