While agricultural expansion and intensification are the biggest threats to biodiversity in the tropics, it is actually smallholder farms – often no bigger than five hectares – that dominate agriculture in this band around the planet. Quite unlike the large, intensively farmed plantations of monoculture species, these mosaic landscapes, composed of millions of small farms, integrate varied and synergistic types of land cover, including crops, fallow areas, forests and secondary forests. Also known as working landscapes, they offer a greater variety of ecosystem services than most homogeneous landscapes – which makes them an important component of global restoration efforts.
According to a 2016 synthesis study in Biotropica, there are more than 1 billion hectares of degraded forest and woodlands across the tropics, and the majority of this area “is suited for mosaic landscape restoration in which primary and second growth forests and on-farm trees are combined with other land uses, including agroforestry, plantations, smallholder agriculture, and human settlements.”
“When I talk about mosaic landscapes, the first thing that comes to my mind is heterogeneity,” says Bernadette Arakwiye, manager of the World Resources Institute’s (WRI) contributions to the African Forest Landscape Restoration Initiative (AFR100). That intermixture is seen in the different land types, the different actors on that land and those people’s different needs, she says.
“So how do we take this broad perspective and apply it to restoration? This requires a deeper understanding of what’s there in terms of land types and peoples’ needs in the first place,” she says, “because it can become messy and not clear enough to do planning. So really it’s where the initial work, the preparation, the assessment of what’s there, all helps to define the right restoration intervention.”
Satellite technology, which is now advanced enough to provide highly precise images of small pieces of land, helps a lot in that effort, Arakwiye adds. WRI uses satellite imagery for monitoring and planning tree-based restoration interventions. “With the improvement in technology, you can see restoration better and sooner,” she says, “and you can continue to track progress and identify areas that need additional interventions. We have seen that with improved technology, we can… map trees with a higher level of accuracy in comparison to what it used to be in the past.”
For the use of the technology to be successful, though, it needs to be implemented by the people living in the landscapes where it’s applied. Their knowledge is important for interpreting the images, contextualizing them with important details that only they would know.
Arakwiye says natural regeneration is the toughest piece of mosaic landscape puzzles, as it is difficult to keep people from disrupting land as it regrows – but progress is being made. “In the restoration movement, I see people really going back to those cost-effective ways to let nature do it on its own. I know it works for forests,” she says. “It should work for other ecosystems, like grasslands or shrublands.”
Attracting investment for mosaic landscape restoration is one of the key challenges for this type of reforestation. Maximizing tree-cover in one area, for example, and optimizing goals such as improving carbon sequestration or biodiversity habitats, while focusing on other functions such as growing food in others, requires long-term engagement which doesn’t necessarily match the funding options. “Donors are often interested in metrics such as the number of trees planted or grown within the lifetime of the grant, so I need to show to that there are actually trees growing,” she says. “And if I leave it to nature, how do I know if it’s going to grow?”
She notes that tree-planting is attractive to donors, but it doesn’t always address the scope of needs in a landscape to the extent that a mosaic approach would. “You’re going to have settlements somewhere, food groves somewhere. You have this bigger whole instead of just tree-planting somewhere. It should be the way to go, but it can be challenging.”
Read the articles in this series as they are published: