Read the paper in Biological Conservation
Photo shows water hyacinth invasion in Kruger National Park
Globally invasions are known to be increasing at a rapid rate, but is this also true for protected landscapes?
The first global-scale assessment of invasive species was undertaken in the 1980s, as part of the international SCOPE programme on biological invasions. Here we took a look at how the situation had changed for 21 of the protected areas around the world that were assessed in the SCOPE programme. We looked at numbers of invasive species, impacts, and management approaches, and how these have changed over the last 30 years.
The research was led by myself (Ross) also involved Louisa (Centre for Environment, Fisheries and Aquaculture Science, UK), Llewellyn Foxcroft (SANParks and C·I·B Core Team Member), Peter Pyšek (Czech Academy of Sciences and C·I·B Associate), and David Richardson (C·I·B Director). A paper from the study was published in Biological Conservation.
Invasive plants showed the highest increase in number of species out of all taxonomic groups assessed (an increase in 31% of protected areas). As was the case in the 1980s, invasive plants are perceived to be the greatest threat to protected areas (60% of regional experts believe the threat level to be increasing from invasive plants in the respective protected areas). The number of invasive mammals has increased in 26% of protected areas. For all other taxa increases in number of invasive species are below 20%, and threat levels remains fairly stable, except for mammals which have shown a large decrease.
Despite the increase in numbers and impacts caused by invasive species in protected areas, several management success stories were documented, and most protected areas are committed to invasive species management; 55% have long-term continuous control and 40% implement ad hoc management. The number of recorded invasive mammals has decreased in 43% of the protected areas in part due to good control, and there have been successful eradication initiatives of one or more species in more than half of the protected areas assessed.
There have also been successes in containing invasive species at the borders of protected areas over long periods, and there were examples of the control of widespread species though innovative adaptive management approaches and the introduction of biological control agents. It is imperative that these initiatives continue, otherwise the impacts of invasive species on biodiversity and ecosystems in protected areas could be much worse.
“This study offers a nice temporal comparison of how the situation of invasive species has changed in protected areas globally. Moving forward with analysis of larger sample sizes would yield clearer insights and could help us to better understand the drivers invasion dynamics in protected areas globally” said Ross Shackleton. “Co-ordination and centralisation of data would help to achieve this”.
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