Invasive exotic species and protected areas
The expected results include: a) sharing and discussing the various technical exercises that have been carried out in the context of the Amazon biome; b) defining the methodological pathway for analysing climate change resilience and vulnerability of protected areas, including their performance in the provision of ecosystem services and the identification of other conservation opportunities that could possibly complement the actual protected areas systems; and c) preparing and validating a preliminary proposal for complementary indicators to evaluate protected areas management efficiency in the light of climate change phenomena.
In that regard, the potential invasion of protected areas by exotic species might serve as an additional indicator. Invasive exotic species are those which for one reason or another have arrived in an area where they do not naturally belong, generally as the result of voluntary or involuntary human actions, and which accordingly bring about alterations to the native biodiversity (and eventually, cultural diversity) of the places where they become established.
“One could consider protected areas to be immune to the introduction of species but the problems that have arisen from the introduction of rats, dogs, pigs, goats and other animals in islands such as those of the Galapagos National Park are well known. The situation in continental areas, such as with the introduction of alien plant species, is less well known”, explains Tarcisio Granizo, coordinator for the WWF Living Amazon Initiative’s Protected Areas and Indigenous Lands Strategy.
“It must be stated that not all introduced species are necessarily ‘invaders’. Those that represent a threat are the ones that are capable of transforming the habitats, competing with and eventually extinguishing the native species”, he adds.
The introduction of exotic plant and animal species is something that affects even those protected areas generally held to be “isolated”.
Recent studies like those of Pauchard and Jiménez have confirmed that the number and abundance of exotic species in protected areas are usually much lower than in the adjacent landscapes more intensely affected by human activities. Nevertheless, over 15 years ago, authors like Lonsdale estimated that introduced species already represented more than 8% of the flora in protected areas and other recent studies have put that figure between 15 and 18% and as high as 60%, for example, in some of the Galapagos Islands. The evidence suggests that even though protected areas present natural and human barriers that restrict the invasion of alien species, those species nevertheless do invade and establish themselves even in the most intact and well preserved areas, and are capable of giving rise to the same impacts that have been registered for areas with much higher levels of anthropic interference.
It is possible in certain scenarios, for climate change to favour the invasion of exotic species. Evidently, climate change is liable to alter the structure and composition of the native communities and consequently, the functioning of the respective ecosystems, establishing a regime of disturbances that heightens the risk of biological invasions.
The various resilience and vulnerability studies conducted in the Amazon basin, especially those led by WWF with funding from the German Environment Ministry’s International Climate Initiative, can help predict future scenarios regarding invasive exotic species and succeed in facilitating implementation of suitable measures to avoid harm to the natural and cultural Andean and Amazon environments and landscapes.