A recent paper published in Global Ecology and Conservation reports on the first global analysis of current patterns and long-term trends in built-up areas within protected areas (PAs) and their surroundings.
The analysis shows to what extent PAs have been effective in limiting building construction within their boundaries, and what pressures they face from building activities outside.
Using the JRC’s Global Human Settlement Layer (GHSL), the analysis demonstrated that buildings cover only a very small fraction of the global extent of PAs compared to their unprotected surroundings. Over the past 40 years, PAs overall have also been relatively effective in avoiding an increase in built-up areas, although small, coastal, less strictly managed or more recent PAs were found to face higher pressure from building activities.
Protected areas as a key tool to promote biodiversity and sustainability
Protected areas (PAs) are usually established and managed to achieve the long-term conservation of nature. They are key to global efforts to conserve biodiversity and ecosystem services. In Aichi Target 11 of the Strategic Plan for Biodiversity 2011-2020 of the United Nations Convention on Biological Diversity (CBD), the 196 CBD Parties agreed to conserve at least 17% of terrestrial and inland water areas by 2020 through effectively and equitably managed, ecologically representative and well-connected systems of PAs. Terrestrial PAs also contribute to the achievement of the United Nations Sustainable Development Goal (SDG) 15 as they seek to protect, restore and promote sustainable use of terrestrial ecosystems.
Terrestrial PAs are expanding and, as of October 2020, they cover 15% of the Earth’s land area, compared to around 10% in 1992 (when the CBD was signed). However, protected areas face many pressures from within and outside their boundaries, including from encroachment, extractive activities, pollution, invasive alien species and climate change.
Why assess built-up structures within and around protected areas?
Most PAs are not free from human habitation and use. They are home to millions of people (including many indigenous peoples), support hundreds of millions of livelihoods, and are used by billions of people for recreation and tourism. Human habitation and use usually requires some built infrastructure, including settlements, roads and visitor facilities. Hence, the majority of the world’s terrestrial PAs include built-up structures within their boundaries or immediate surroundings. These man-made structures range from individual buildings (e.g. visitor centres, museums, hotels, lodges, or religious buildings) to villages, towns and even cities. The extent and evolution of built-up areas within and around PAs can be important indicators of PA effectiveness and the pressures PAs face.
The JRC analysis therefore calculated for over 52,000 PAs (all larger than 5 km2) and their 10-km unprotected buffer zones the percentage of land area covered by built-up areas for 1975, 1990, 2000 and 2014 to answer the following questions:
- How much land within and around PAs is covered by built-up structures?
- How has built-up area within and around PAs changed over the past 40 years?
- How do the patterns and trends differ between continents, regions and countries, and between different types of PAs?
Current patterns and long-term trends in built-up area pressures
Combining the Global Human Settlement Layer (GHSL) with the World Database on Protected Areas (WDPA), the analysis revealed some striking findings. While built-up areas cover 0.57% of all land (either unprotected or protected) globally, they are much less prevalent within PAs (0.12%) and much more widespread within the 10-km unprotected buffer zones of PAs (2.71%). This means that the percentage of built-up areas within PAs is around 23 times smaller than within their surroundings. Built-up areas within PAs are, however, very unevenly distributed across continents and countries (see figure below). The lowest presence of built-up structures within PAs is found, at the continental level, in Oceania, Africa and the Americas. In Europe (including Russia), 0.378% of the PA network is built up, which increases to 1.196% if only Western Europe is considered. At the country level, the percentage of built-up areas varies, for example from 2.87% in Belgium to countries such as Iceland with less than 0.001%
Small PAs have, on average, higher percentages of built-up area than larger ones. For example, the average built-up coverage is 30 times larger in terrestrial PAs with sizes ranging from 5 to 25 km2 (1.20%) than in terrestrial PAs larger than 1,000 km2 (0.04%). Built-up area was globally more than double in coastal PAs compared to non-coastal PAs, reflecting the concentration of human populations, activities and facilities near the sea.
The analysis also found that PAs that were established several decades ago have considerably fewer built-up structures than more recently designated PAs, and that older PAs have experienced lower rates of increase in built-up areas than more recent PAs. Overall, however, built-up areas increased 23 times more in unprotected buffers than within PAs over the past 40 years.
Implications of increasing built-up area within and around protected areas
Given that PAs are established and managed to conserve nature, there should be fewer built-up structures within PAs compared to unprotected land. This has been clearly confirmed by the analysis. This finding is important because, in many cases, there are direct and indirect pressures associated with buildings, settlements, urbanisation and other forms of human-made infrastructures that may affect biodiversity and ecological processes.
On the other hand, well-planned and controlled increases in built-up structures within PAs are not necessarily in conflict with conservation objectives. They may even be beneficial to PA success by supporting the infrastructures required for adequate management of the PAs and the threats to their conservation values. Buildings used as ranger facilities, PA visitor or nature interpretation centres or wildfire extinction infrastructure, for example, are part of the integrated management of PAs and are necessary for their effective management.
Although PAs appear to be effective in limiting building construction, the analysis also shows that PAs face considerable pressure from building activities in their surroundings. The high coverage and increase of built-up structures in close proximity to PAs may have significant effects on the ecological processes and biodiversity within PAs. For example, habitat transformation and fragmentation outside their boundaries may increasingly isolate PAs and the wildlife they protect, thus limiting the effectiveness of PAs for biodiversity conservation.
Building activities within and around protected areas need careful planning
The increasing pressure from built-up areas within, and particularly around PAs, highlights the need for adequate planning, management and governance of PAs in their wider landscape context. The trends revealed by the analysis may only intensify in the future, both because of the projections of human population growth and because of the additional expansion of the PA systems required to meet Aichi Target 11 and any future conservation targets.
The analysis therefore provides an important baseline for monitoring future trends in built-up areas within PAs and their surroundings.
- Data de publicação
- 11 novembro 2020