Increased human activity around one of Africa's most iconic ecosystems is "squeezing the wildlife in its core", damaging habitation and disrupting the migration routes of wildebeest, zebra, and gazelle, an international study has concluded. The study, led by the University of Groningen and with collaborators at 11 institutions around the world, looked at 40 years of data, and revealed that some boundary areas have seen a 400 percent increase in human population over the past decade while larger wildlife species populations in key areas (the Kenyan side) were reduced by more than 75%. The findings are published this week in the scientific journal Science. Dr. Michiel Veldhuis, lead author of the study from the University of Groningen: "This finding alters our view on what is needed to protect biodiversity."
The Serengeti-Mara ecosystem is one of the largest and most protected ecosystems on Earth, spanning 40,000 square kilometers and taking in the Serengeti National Park and Maasai Mara National Reserve in East Africa. Every year a million wildebeest, half a million gazelle and 200,000 zebra make the perilous trek from the Serengeti Park in Tanzania to the Maasai Mara reserve in Kenya in their search for water and grazing land.
Now, an international team of scientists has discovered that increased human activity along the boundaries is having a detrimental impact on plants, animals, and soils. The study reveals how population growth and an influx of livestock in the buffer zones of the parks has squeezed the area available for migration of wildebeest, zebra, and gazelles, causing them to spend more time grazing less nutritious grasses than they did in the past. This has reduced the frequency of natural fires, changing the vegetation and altering grazing opportunities for other wildlife in the core areas.
The team shows that the impacts are cascading down the food chain, favoring less palatable herbs and altering the beneficial interactions between plants and microorganisms that enable the ecosystem to capture and utilize essential nutrients. The effects could potentially make the ecosystem less resilient to future shocks such as drought or further climate change, the scientists warn.
The authors conclude that, even for reasonably well-protected areas like the Serengeti and Mara, alternative strategies may be needed that sustain the coexistence and livelihood of local people and wildlife in the landscapes surrounding protected areas. The current strategy of increasingly hard boundaries may be a major risk to both people and wildlife.
Dr. Michiel Veldhuis, lead author of the study from the University of Groningen noted: "There is an urgent need to rethink how we manage the boundaries of protected areas to be able to conserve biodiversity. The future of the world's most iconic protected area and their associated human population may depend on it."
Dr. Simon Mduma, Director of the Tanzanian Government's Wildlife Research Institute commented: "These results come at the right time, as the Tanzanian government is now taking important steps to address these protected areas boundary issues on a national level. 'This paper provides important scientific evidence of the far-ranging consequences of the increased human pressures around the Serengeti-Mara ecosystem, information that is now urgently needed by policymakers and politicians."
Dr. Simon Mduma: "We should re-think our protected area strategy, making sure that conservation efforts do not stop at protected area boundaries."
Prof. Mark Ritchie from Syracuse University: "Keeping people out of an area to protect biodiversity is not enough - we need to integrate human activities and conservation outside reserves as well."
Dr. Joseph Ogutu from the University of Hohenheim: "The intense compression of a large protected area, such as the Serengeti-Mara, should ring alarm bells because most other protected areas are far smaller in size and therefore experience even more intense pressures from human activities impinging on their borders. In countries where far more wildlife are still found outside than inside protected areas, such as Kenya where more than 65% of wildlife occur outside protected areas, expanding human population size, livestock and human activities pose serious and unprecedented threats to wildlife populations."
Dr. Colin Beale from the University of York: "Protected areas across East Africa are under pressure from a wide range of threats. Our work shows that encroachment by people should be considered just as serious a challenge as better known issues such as poaching and climate change."
Dr. Kate Parr from the University of Liverpool: 'Our results show that we cannot rely on the sheer extent of protected areas to conserve biodiversity - human impacts are pervasive and threaten even our most iconic reserves."
Dr. James Probert from the University of Liverpool: "The Serengeti-Mara is one of the largest trans-boundary protected area complexes in the world, and yet we find the negative impacts of human activities impacting its core."
Dr. James Probert: "It is clear that even large protected areas, with strict restrictions on what human activities can take place, can be indirectly affected by human populations at their boundaries."
Patrick Wargute from the Directorate of Resource Surveys and Remote Sensing, Nairobi, Kenya: 'These findings will inform policies and pieces of legislation for the conservation and management of wildlife for sustainable development."
Reference: Veldhuis et al. Cross-boundary human impacts compromise the Serengeti-Mara ecosystem. Science 29 March 2019