Habitat Based Conservation Strategies

This sub-topic really applies to the design of protected areas. It is important that students have a case study to which they can refer and in this case, again, I like the students to choose their own protected area. The assignment can be found in Protected Area Case Study. This way students can apply the knowledge from this sub-topic.

We start this topic by watching the short film, The Guide, from HHMI Biointeractive then review the criteria for success in designing a protected area.

There are some guiding questions and short answer questions to support this topic on the page.

Designing Protected Areas

One of the most important requirements of any nature conservation strategy is to preserve the largest possible amount of undisturbed environment so that species and habitats can continue in as near natural a state as possible

In a number of countries there has been a shift in emphasis away from simply designating as many sites as possible for protection, towards creating an optimum network of protected sites. Such a network takes into account such factors as:

• The need to conserve as wide a range of species and habitats as possible

• The need to manage protected sites in sustainable ways, using available resources

• The need to have a balance between special sites (with some unique properties) and ordinary sites (which protect representative or characteristic species and habitats that may not be endangered themselves)

Networks of Protected Areas

Protected areas vary in size, but many – particularly in crowded countries like Britain, where sites are mostly acquired as and when opportunities arise – are small and isolated. Ecologists have established clear links between habitat fragmentation and species extinction, which means that larger protected areas are usually much more valuable for conserving species than smaller ones. The aim is thus to:

• conserve as wide a range of species and habitats as possible
• manage protected sites in sustainable ways, using available resources
• balance between special sites (with some unique properties) and ordinary sites (which protect representative or characteristic species and habitats)

Island Biogeography

Ecologists have established clear links between habitat fragmentation and species extinction.

Therefore larger reserves are usually much more valuable for conserving species than smaller ones.

Important decisions have to be made about the optimum size, shape, pattern and geographical coverage of reserves often based on principles of island biogeography.

The image shows the number of species found on an island based on the rate of immigration (to the island), the rate of extinction (on the island), the distance from the mainland and the size of the island.

Try these associated questions  3.4 Island Biogeography - Data Analysis 

Conservation Corridors

• Conservation corridors (like hedges of strips of natural vegetation between reserves) allow migration and movement of species between the isolated islands of protection.

The Carnaby Cockatoo:

• The cockatoos require a close association between breeding and feeding sites during the breeding season. If these two very different habitats are not within a reasonable distance of each other, breeding attempts fail.
• Need to create native habitat corridors to link areas of native vegetation, especially in extensively cleared agricultural areas such as the Western Australian wheatbelt.
• Find out more about these cockatoos here.

There are also simple technocentric solutions involving the building of animal bridges.

Criteria for Success: Size and Proximity to Potential Human Interference

• The protected area needs to be large enough to hold a viable population of the species it is trying to conserve.
• Although consideration can be given to the surrounding area, it must be considered that this land use could change. Buffer zones are usually incorporated for this reason.
• Migratory species must have at least feeding and breeding sites. The image is a Northern Bald Ibis (Waldrapp Ibis) which has required protection of several areas through its migration route as well as the feeding and breeding sites.
• Wide-ranging species need particularly large areas, while an orchid may need a tiny area.

 Community Involvement

One of the most critical and challenging criteria for a successful protected area is community involvement. If the community haven't been involved in the establishment of a protected area then it could fail. Removing local people, failing to provide alternatives or job creation can all create problems.

A great example of a well funded but integrated project is the Gorongosa National Park in Mozambique. There is a short film (34 minutes) about the park and the opportunities offered to a local boy when he met the famous scientist EO Wilson. The full film can be viewed or downloaded from the HHMI site here but here's a trailer.

Criteria for Success: Shape and Edge Effects

• This may be determined by pre-existing natural features.
• A circular shape is best as it has the smallest amount of edge possible for a given area.
• The edge zone is not representative of a "pure" ecosystem and so more edge means less "pure" ecosystem.
• It also increases the vulnerability of the core protected area. 
• Studies have been made of different plot sizes in the Amazon with similar sizes in undisturbed forest. The smaller the size the greater the loss of biodiversity.

So is there a Best Strategy for Designing Protected Areas?

• There may be no “best strategy” for protected area design.
• Habitat diversity may be more important than size in a protected area
• In some cases several small protected areas may be better than one large one because they cover a wider range of environmental conditions.
• A number of smaller protected areas may be more useful in the case of natural disasters where there is less risk of the elimination of a rare species.
• Protected area design depends very much on the purpose of the protected area: is the focus a species, an ecosystem or a series of ecosystems.