5.5 Ecological reserve design using GIS
One of the main tools in maintaining biodiversity is the use of conservation areas (also known as reserves or protected areas), such as national parks, game reserves, or Sites of Special Scientific Interest (SSSI’s). Special legislation is used to protect biodiversity in such areas by restricting other economic activities. Some conservation areas are government-owned rather than privately owned. Deciding exactly where conservation areas are to be positioned is one of the key types of spatial decision in ecological management. This object examines how GIS can be used to help identify appropriate locations for conservation areas and explains how information about conservation areas is usually stored.
Conservation Areas as Spatial Data
In a GIS, conservation areas tend to be stored as vector polygon data. In terms of attributes, the International Union for the Conservation of Nature and Natural Resources (IUCN) identifies six main types of conservation area, depending on their main purpose:
Table 1. IUCN categories of Conservation Area
|Category 1a: Strict nature reserve||protected area managed mainly for science|
|Category 1b: Wilderness area||protected area managed mainly for wilderness protection|
|Category II: National Park||protected area managed mainly for ecosystem protection and recreation|
|Category III: Natural Monument||protected area managed mainly for conservation of specific natural features|
|Category IV: Habitat/species management area||protected area managed mainly for conservation through management intervention|
|Category V: Protected landscape/seascape||protected area managed mainly for landscape/seascape conservation and recreation|
|Category VI: Managed Resource Protected Area||protected area managed mainly for the sustainable use of natural ecosystems|
A more detailed description of these categories is provided by UNEP (see references). Any one country typically has its own set of categories for conservation areas and these are often numerous, complex and varied. In the UK, for example, types of conservation area include Ramsar sites (sites where wetland is protected based on the Convention on Wetlands of International Importance Especially as Waterfowl Habitat), National Nature Reserves, Sites of Special Scientific Interest, Special Protected Areas, and Special Areas of Conservation (see the English Nature web site below). The legislation protecting each of these types of conservation area is slightly different.
Using GIS to plan conservation areas
One of the most straightforward and widely known approaches in which GIS has been used to help plan conservation areas is the Gap Analysis Plan (GAP) in the USA (see the GAP reference below). The concept of gap analysis is simple: map layers are created of major vegetation types and key species of vertebrates. These maps are then overlaid onto a second map depicting the extent of protected areas. Any species or vegetation communities that are currently poorly protected through the existing network of conservation areas can then be identified. The Gap Analysis Plan makes no recommendations about what should be done to protect such species – the information is simply passed on to relevant decision-makers to inform their judgments.
There are more sophisticated software tools available for deciding where nature reserves should be located, notably the WorldMap software produced by the UK Natural History Museum (see references below). Unlike the Gap Analysis Program, the WorldMap software tries to identify the priority areas for conservation instead of leaving this to the decision-maker. The WorldMap software takes map layers of many different species distributions and analyses them together. WorldMap tries to identify new sites for conservation areas by maximising the biodiversity within the protected areas. This is done either by:
- identifying ‘hot spots’ of diversity, where a very large number of different species can be found.
- identifying ‘hot spots’ of rarity, where several species occur that are not found in any other location. Such species that are found only in a very restricted geographical range are sometimes referred to as endemic and we can therefore talk of ‘hot spots’ of endemism.
- identifying sites that will preserve the greatest number of additional species over and above those already protected by existing conservation areas. This is known as a complementarity method to choosing areas, since it involves finding sites for conservation that are complementary to those already designated.
Depending on which of these approaches is adopted, different areas may be identified as priorities for conservation.
Q. Can you think of any issues involved in selecting conservation areas that neither WorldMap nor the Gap Analysis Program address?
We can think of conservation as just one of several different land uses, competing with agriculture, forestry, tourism (golf courses and so on), and demand for housing land. WorldMap and the Gap Analysis Program really only consider the suitability of the land for conservation, but not for these other land uses like agriculture or forestry. If two areas have similar conservation value, it makes sense to conserve the one that has the least economic value for tourism, forestry and other uses. WorldMap and the Gap Analysis Program do not consider such trade-offs between competing land uses.
From a landscape ecology point of view, the other important issue is the spatial connectivity of conservation areas. Imagine that there are two areas that have similar conservation value and one lies between two existing national parks, whilst the second does not. It may make sense to conserve the first area rather than the second, since it will act as a ‘corridor’ for animals migrating between the two national parks.
A Gap Analysis for Zimbabwe’s conservation areas
If you are using ArcGIS Desktop, download the zip file, which contains data on major land cover types and conservation areas in Zimbabwe. If you are using ArcGIS Pro, please download this zip file instead. When you have familiarised yourself with the data, undertake the GIS operations described in the pdf file.
References (Essential reading for this learning object indicated by *)
* An excellent, but very high-level and demanding, description of how GIS can be used to plan conservation areas is available from the UK Natural History Museum. The WorldMap software, which has been specifically designed for identifying suitable sites for conservation areas, is also available for downloading from the Natural History Museum web site: https://s10.lite.msu.edu/res/msu/botonl/b_online/library/biodiversity/index.html
To see examples of different types of conservation area data set, visit the Natural England open data portal: http://naturalengland-defra.opendata.arcgis.com/
Note that you will need to complete a registration form before downloading any of these data.
More details of the Gap Analysis Program in the US are available here: http://gapanalysis.usgs.gov/
The land cover data used in the practical were derived from the US Geological Survey’s EROS Global Land Cover facility, now best accessed via here: https://www.usgs.gov/centers/eros/science/usgs-eros-archive-land-cover-products-global-land-cover-characterization-glcc?qt-science_center_objects=0#qt-science_center_objects