Low genetic diversity hampers restoration efforts
The future resilience of restored forests and landscapes across the globe may be threatened if there is little genetic diversity in the trees that are used.
Speakers at a session during Tree Diversity Day, organized by the World Agroforestry Centre at the 12th meeting of the Conference of Parties to the Convention on Biological Diversity (COP12) outlined the importance of ensuring the right trees get planted in restoration efforts and genetic diversity is carefully considered and monitored.
“The genetic diversity of species is the foundation for food security,” said Linda Collette, Secretary of the Commission on Genetic Resources of the Food and Agriculture Organization (FAO) of the United Nations. “The genetic resources for food and agriculture are unique and irreplaceable resources that help production systems adapt to climate change, ensure healthy and diversified nutrition for all as well as secure livelihoods.”
In 2014, the FAO published the first ever State of World’s Forest Genetic Resources which found that nearly half of all utilized forest species are under threat. It shows how the conversion of forests to pastures and farmland, overexploitation and climate change are all impacting on the food, goods and services that forests provide for the survival and wellbeing of humanity.
For example, in 1900 Sumatra, Indonesia had 16 million hectares of lowland rainforest. In 2010 there were just half a million hectares remaining.
“The contribution of forests and trees to boosting food security, reducing poverty, and promoting sustainable development depends on the availability of a rich diversity of tree species,” says the FAO. This diversity is what enables breeders to select for desirable traits in domesticating improved tree species. It also ensures forests can adapt to changing environmental conditions or survive pests and diseases.
The report found that knowledge on genetic resources is poorly managed and current institutional and technical capacity to do so is insufficient.
Lars Graudel, Domain Leader for Tree diversity, Domestication and Delivery at the Word Agroforestry Centre, together with colleagues, has developed a framework for a set of genetic level indicators for trees which could help countries move towards meeting many of the report’s recommendations. This work was published in 2014 in the journal, Forest Ecology and Management.
“Indicators for genetic diversity are still largely absent from comprehensive bio-monitoring schemes, even though genetic diversity is acknowledged as a major element of biodiversity,” says Graudal.
“We have proposed 7 indicators that will tell us about the state of genetic diversity, its benefits and responses,” explained Graudal. “The indicators operate from the global level down to local stands of trees.”
He outlined how indicators need to reflect trends and patterns, how these may affect us and what we should do about them. “They are not just measuring sticks, they are important for guiding action.”
Graudal believes this framework can help in developing strategies to manage tree genetic resources to support more resilient and productive landscapes; vital especially in terms of mitigating and adapting to global changes, such as in climate.
Riina Jalonen, Associate Scientist with Biodiversity International, explained how the indicators developed by Graudal and colleagues can be used to assess the success of restoring resilient forests.
Numerous countries worldwide are responding to the 15th Aichi Target to restore degraded ecosystems by setting forest and landscape restoration targets in millions of hectares and initiating large scale tree planting programs. But how resilient will these newly established forests be, and how will they contribute to climate change mitigation and adaptation, asked Jalonen.
“The resilience of these forests is largely determined by the genetic diversity of the planting material and how well it is matched to current and predicted future environmental conditions on the restoration site.”
Without this diversity we see problems such as in-breeding emerge. In Sabah, Indonesia Acacia magnum was introduced in 1967 from Australia to reforest more than 15,000 hectares. But the planting material was only sourced from 2 small stands, resulting in a 44 per cent reduction in average height of the trees from the first to the third generation.
A review of 23 studies into genetics in relation to forest restoration found that genetic diversity is significantly lower in restored forests. This can perhaps be attributed to many flaws in restoration efforts, such as seed only being collected from a low number of trees, not necessarily from quality sources and often from areas far away from the restoration site.
Jalonen says seed source forests must be large and genetically diverse enough to avoid inbreeding and to contain genetic material for natural selection. “Good seed collection practices must be observed to capture the genetic diversity of the seed sources.”
View the presentations from this event on SlideShare:
Landscapes and restoration: Indicators of forest genetic diversity, erosion and vulnerability, and genetic considerations in forest landscape restoration
- Forest Genetic Diversity: Building knowledge-implementing priorities – Linda Collette, FAO
- Indicators of tree genetic diversity for monitoring status and trends of forest genetic resources and the effectiveness of ameliorative actions – Lars Graudal, World Agroforestry Centre
- Assessing the success of forest and landscape restoration efforts – what do genetic diversity indicators tell us? – Riina Jalonen, Bioversity
Graudal L et al. (2014). Global to local genetic diversity indicators of evolutionary potential in tree species within and outside forests. Forest Ecology and Management.
Bozzano M, Jalonen R, Thomas E, Boshier D, Gallo L, Cavers S, Bordács S, Smith P, Loo J. (2014). Genetic considerations in ecosystem restoration using native tree species. In: State of the World’s Forest Genetic Resources – Thematic Study.
Find out more about the World Agroforestry Centre’s participation at CBD COP12