Cape Argus

Managing invasive species

New framework developed for monitoring and reporting in World Heritage Sites

- ROSS SHACKLETON LOUISA WOOD Shackleton is a postdoctor­al student, Conservati­on and Invasion Biology, Stellenbos­ch University, and Wood is a scientist with a focus on aquatic nonnative species

MORE than 250 000 protected areas make up around 15% of the globe’s surface area. They include World Heritage Sites, national parks, provincial parks, nature reserves and many other sites on land and water.

These protected areas are crucial for preserving the world’s biodiversi­ty and ecosystem functions. They also support the well-being of millions of people.

Protected areas are increasing­ly under threat because of humaninduc­ed drivers of global change. These include poaching, pollution, climate change and biological invasions caused by invasive alien species.

Invasive alien species are organisms moved by humans to new regions where they traditiona­lly don’t occur. For various reasons, these species spread uncontroll­ably. They can negatively affect their new environmen­ts.

Invasive alien species are one of the leading threats to biodiversi­ty in protected areas globally. For example, in South Africa, invasive tree species in Table Mountain National Park are changing naturally occurring fire and water systems.

Managing invasive alien species is also a huge financial burden for many protected areas. For instance, SA National Parks and Working for Water, an ecosystem restoratio­n programme, spend on average R2 million a year for invasive alien species control in the Kruger National Park, one of Africa’s largest game reserves.

A team of researcher­s and managers working in invasion science have been monitoring invasive alien species in World Heritage Sites across the world. When reviewing documents about invasions in these sites, we found reports were hard to compare because no systematic method of reporting was followed.

We therefore developed a new framework to guide the monitoring and reporting of invasive alien species in natural World Heritage Sites globally.

The framework allows assessors to assign an overall threat score to a World Heritage Site. This will help improve the monitoring and control of invasive alien species at these sites.

A review of United Nations Educationa­l, Scientific and Cultural Organisati­on and Internatio­nal Union for Conservati­on of Nature documents about invasive alien species in World Heritage Sites revealed reporting problems.

Essential data were often not reported in documents or not detailed enough to be useful. This made it difficult to assess changes to levels of threat or progress in the management of invasive alien species in the sites over time.

The framework we developed has three components.

The first focuses on monitoring and reporting of the current status of biological invasions. It relates to compiling lists of alien species, assessing how they were introduced into the sites, identifyin­g and reporting their impact.

The second component looks to the future and aims to predict future threats and management needs.

The third component assesses knowledge gaps and the overall threat levels of invasive alien species to the site.

To test the framework, we did seven in-depth case studies in different social-ecological contexts on five continents. These include the Aldabra Atoll (Seychelles tropical islands), Serengeti National Park (Tanzania) and Vredefort Dome (South Africa).

We drew informatio­n from the literature and consulted local researcher­s and managers to get additional informatio­n about each site. Applying the framework yielded more informatio­n than past monitoring initiative­s.

For example, the threat level shown in the 2017 World Heritage Outlook for the Serengeti and Vredefort Dome sites was “data deficient”. They’re now categorise­d as facing moderate to high threats from biological invasions based on our assessment informed by the framework. Just over half of the World

Heritage Sites globally are formally listed as being threatened by biological invasions, from over 300 different invasive alien species. But the number of sites and invasive alien species is probably under-reported and likely to be much higher.

Use of the framework more than doubled the number of invasive species reported for all sites except for Aldabra. This site has fewer invasive alien species now due to effective eradicatio­n and control initiative­s. The total number of invasive species in the site dropped from seven to five.

A major issue that limits efficaciou­s management is the availabili­ty and collation of data about invasions for many protected areas. This lack of informatio­n limits understand­ing and hinders the formulatio­n of robust policy or control responses.

Better transparen­cy and standardis­ation of long-term monitoring and reporting of biological invasions in protected areas will allow for meaningful analysis of trends over time. This will also guide adaptive management. Further research that collects baseline data and empirical evidence on invasions in protected areas is also crucial.

We hope that the framework we’ve developed will help to do this and become a global norm moving forward.

 ?? MOTSHWARI MOFOKENG African News Agency (ANA) ?? A WORKER clears water hyacinth at the mouth of Inanda Dam in KwaZulu-Natal. Invasive species like hyacinth pose an increasing threat to the world’s protected areas, say the writers.
MOTSHWARI MOFOKENG African News Agency (ANA) A WORKER clears water hyacinth at the mouth of Inanda Dam in KwaZulu-Natal. Invasive species like hyacinth pose an increasing threat to the world’s protected areas, say the writers.
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