Tropical parks need more support

The Serengeti National Park was the largest surveyed

By environment correspondent Alex Kirby

North American researchers say tropical parks, despite widespread doubts about their utility, are an effective way of protecting species and habitats.

They say that parks are a good strategy for conservation, and deserve more support. And they argue for the establishment of new parks to help to meet the threats to biodiversity.

Tropical parks have been surprisingly effective at protecting the ecosystems and species within their borders

But the researchers say the "strictly protected areas" are better at guarding against some threats than others.

The team, from the Washington-DC based group Conservation International and the University of British Columbia in Vancouver, Canada, publish their findings in the journal Science.

They looked at conservation areas ranging in size from the small Bomfobiri Wildlife Sanctuary in Ghana (5,300 hectares) to the vast Serengeti National Park in Tanzania (1,476,300 hectares)

Broad improvement

In total, they assessed the impacts of human threats on 93 protected areas in 22 tropical countries to test the parks' effectiveness in protecting biodiversity, using a questionnaire to collect data on a number of issues.

Some parks find it difficult to resist loggers

These included land-use pressure (land clearing, logging, hunting, grazing and fire), local conditions (for example, the presence of human settlements and the degree of access to the parks), and management activities, such as the number of guards and the level of community involvement in the park management.

All the parks they studied had been in existence for at least five years.

Part of the study involved assessing the parks' effectiveness at preventing land clearing by comparing the current extent of clearing with that at the time the park was established.

'Substantial achievement'

The authors write: "We found that 43% of the parks have had no net clearing since establishment. In an additional 40%, land formerly under cultivation was incorporated into park boundaries, and had been able to recover, leading to an actual increase in vegetative cover. This is a substantial achievement."

Fire clears land - and also the wildlife

A comparison of the human impacts within the parks with those in the 10-km belt surrounding them showed that "the parks in our sample are under great pressure from clearing, hunting and logging, and, to a lesser extent, fire and grazing".

Yet the researchers conclude: "A comparison of the conditions inside the parks with the surrounding area shows that for all five threats, parks were in significantly better condition than their surrounding areas."

Parks, though, are rather less effective at withstanding some pressures, like logging and hunting, than land clearance, where most remain either intact or only slightly cleared.

Guarding influence

The research team also investigated what model of park management appeared to work best. "Park effectiveness," they say, "correlated most strongly with density of guards.

"The median density of guards in the 15 most effective parks was more than eight times higher than in the 15 least effective.

"However, enforcement capacity (a composite variable of training, equipment and salary) was not found to correlate with effectiveness, suggesting that these characteristics are less important than the presence of guards."

The authors also found a "significant" correlation between effectiveness and the level of deterrents applied to illegal activities, though deterrence seemed less effective against hunting than other threats.