By J. Leighton Reid
J. Leighton Reid is an Associate Professor of Ecological Restoration in the School of Plant and Environmental Sciences at Virginia Tech.
The acid test of our understanding is not whether we can take ecosystems to bits on pieces of paper, however scientifically, but whether we can put them back together in practice and make them work. Anthony Bradshaw, 1987
Ecological analyses in the Choco region are greatly complicated by the inadequacy of the taxonomic data base. Alwyn Gentry, 1986
In northwestern South America there is a long, thin strip of rain forest that stretches from western Ecuador through Colombia to eastern Panama. This area, known as the Chocó, contains some of the wettest rain forests on Earth, with certain areas receiving more than 11,000 mm (433 inches) of rain each year. The Chocó is isolated from the Amazon basin by the Andes, and as a result many Chocoan species are found nowhere else. Despite its relatively small size, the Chocó is home to about 3% of the world’s vascular plants and 63 endemic bird species. More species are described each year.
Although the Chocó rain forest has been relatively well preserved on the west slope of the Andes and in lowland Colombia, the section in lowland Ecuador is mostly gone. More than two thirds (68%) of lowland northwestern Ecuador has been deforested to make space for cattle pastures, oil palm plantations, and cacao plantations. Federally protected areas have had mixed success in preventing or reversing this decline. The Cotacachi-Cayapas Ecological Reserve in the higher elevations of the western slope is still about 99% forested, while the Mache-Chindul Ecological Reserve in the lower coast range retains only 61% of its forest.
Several non-profit organizations are working to shore up protection of the remaining forest and ensure an evolutionary future for Chocoan biodiversity. One of these is the Foundation for the Conservation of the Tropical Andes (FCAT), an Ecuadorian non-profit committed to achieving durable Chocoan biodiversity conservation in collaboration with local residents and scientists, who call themselves the FCATeros. To advance their mission, the FCATeros are researching local ecosystems and socio-ecological systems, building bioliteracy through youth education, developing local capacity for science and conservation, and helping local farmers diversify their income through regenerative agriculture. FCAT is also purchasing land for conservation and to connect remaining forest fragments, with a goal of conserving 10,000-hectares (~25,000 acres) to sustain healthy populations of Chocoan plants and animals. They have already acquired 700 hectares (~1700 acres) – a mix of primary rain forest and regenerating agricultural lands.
Some of the degraded land within the FCAT Reserve is regenerating quickly into secondary rain forest. This is particularly the case in areas that were deforested recently and retain many remnant trees, a seed bank, and resprouting tree stumps. Other areas were deforested longer ago and were used more intensively for cattle grazing and cacao production. These areas have more compacted soils, fewer remnant trees, and introduced African forage grasses that inhibit native tree regeneration. As the reserve expands, FCAT will need cost-effective ecological restoration techniques to fill gaps between forest fragments.
The Choconexión Experiment
In 2021, FCAT invited me to help develop a restoration strategy to meet this need. We formed a collaborative local and international team of scientists and conservationists to recommend restoration strategies for about 80 hectares (~200 acres) of degraded agricultural land. For roughly two thirds of the land (the less-degraded part), we recommended a natural regeneration approach; cattle were removed and the area was allowed to regenerate without further intervention. On the remaining and more degraded area, we developed an experimental restoration study to identify a cost-effective strategy for FCAT to apply on other degraded lands. In doing so, we also took the opportunity to test a basic theory about how ecological communities assemble themselves.
For our restoration experiment, we chose a technique called applied nucleation, which mimics the patchy spatial patterning of natural forest regeneration. Applied nucleation is intermediate between natural regeneration and more extensive native tree plantations. I studied this method for my PhD research in southern Costa Rica, where over more than 20 years we have found that applied nucleation produced more biodiverse secondary forest more consistently than natural regeneration, and it produced nearly equivalent biodiversity recovery compared to more extensive tree plantations for about 1/3-1/4 the cost. At FCAT, we sought to test applied nucleation in the Chocoan context and to optimize some of the tree planting parameters – including how many species to plant, which particular species to plant, and how widely to space the tree planting patches.
In 2022-2023, FCAT installed the experiment by clearing pasture grasses and planting more than 3,000 native tree seedlings into 116 15×15-m plots (roughly 50×50 feet). Native trees were all of which were harvested as seed from mother trees in the surrounding landscape and propagated in hand-made nurseries at the FCAT field station. In half of the plots, we planted 19 tree species, and in the other half we planted four species to test the influence of tree diversity on forest recovery. Tree planting plots were separated from one another by either 10, 20, or 30 m to test the optimal spacing. We assumed that planted trees would be able to extend their branches to fill a 10-m gap within a few years, but that it would take many years for them to fill a 30-m gap.
Finally, in half of the plots we planted three fast-growing pioneer tree species that we knew would produce a lot of fruit, and in the other half of the plots we planted fast-growing trees that would not produce much fruit, either because they were wind-dispersed or because their fruits were not appealing to most animals. We built this test into the experiment because the vast majority of plants in western Ecuador have seeds that are dispersed by animals. We thought that if we planted trees that quickly produce many fruits, these trees would attract fruit-seeking animals that would visit the sites more often and deposit plant seeds from the surrounding rain forest. If we are right and that effect is strong enough, it might be possible to plant fewer trees or a lower diversity of trees and have animals compensate by planting more trees (and other plants) for us. This would save FCAT money and allow us to reforest larger areas or put more funds into land acquisition and other mission-driven activities.
By creating differences in early successional fruit availability, this experiment also represents a basic test of how the first trees to establish in a rain forest influence the types of trees that establish later. In other words, it is a test of priority effects in rainforest reassembly.
There are four high-level processes that determine which species will gain membership in a local ecological community. These are dispersal, selection, drift, and speciation. In many parts of the world, environmental selection imposes strict limits on which species can live in a given place. For example, there is no woody plant that can tolerate the combination of freezing temperatures and inundation in salty water. Thus, mangroves exist only in the tropical and subtropical latitudes and herbaceous salt marsh plants occupy similar environments closer to the poles.
It is possible to make very good predictions about the kinds of plants that will form a local community if you know: (A) the traits of the plants in the community, (B) the relationship between those traits and a set of important environmental variables, and (C) the values or ranges of the important environmental variables at a local site. However, these models work best in places with relatively harsh environments, such as boreal wetlands and arid mountain ranges. Predicting rainforest community assembly is harder because the abiotic environment is more benign (generally warm and wet), and as a result, the particular species that arrive and survive may be more strongly determined by biotic gradients – potentially including fruit availability.
As of October 2025, the Choconexión Project has been planted for 2-3 years (it was planted in two rounds in 2022 and 2023). Most species survived well (82% overall, range ~40-95%) and those that did not survive are being replanted. Some of the balsa are more than 10 m (32 feet) high after two years of growth, and a fig species (Ficus tonduzii) has begun to produce fruit. This year we will develop tree phenology and fruit availability protocols to characterize the effects that experimental treatments are having on the biotic environment.
A growing number of collaborators and students are monitoring a wide range of ecological variables within the experiment. Last year, an expert botanist, Milton Tirado, established a baseline of the initial woody plant community at 192 points throughout the experiment. Others have also described gradients in soil quality, identified and tagged remnant trees, produced LiDAR data from a flyover at the start of the experiment, and generated annual orthomosaics with a drone. Monitoring is underway for birds, frogs, and other wildlife. Studies have also begun to measure secondary seed dispersal and recovery of the plant-frugivore network. In addition, the experimental landscape is being used for several other projects, including studies of caterpillar predation risk, volatile organic compound composition, and bat disease ecology, among others.
In the next few years, we plan to replicate this experiment in additional sites and to develop protocols to measure plant and animal functional traits, abiotic environmental gradients, and seed rain. These will allow us to rigorously test how much more information about rain forest reassembly can be gained when dispersal-mediated priority effects are considered in addition to environmental filters.
More importantly, the results of this experiment will provide pragmatic and timely information to FCAT and others working to preserve the Ecuadorian Chocó. By refining and optimizing applied nucleation designs for this unique landscape, we will make limited conservation funding go farther to restore trophic and landscape connectivity in the fragmented Mache Chindul Ecological Reserve.
The Choconexión Project is a collaborative effort that involves too many partners to fully enumerate. The experiment was co-designed by Zak Zahawi, Jordan Karubian, Luis Carrasco, and Carlos Aulestia, with support from many others. Carlos led the reforestation with a team of FCATeros. The restoration was funded by the US Fish and Wildlife Service to provide overwintering habitat for Neotropical migratory songbirds. Subsequent ecological monitoring is funded by the US National Science Foundation (DEB 2339839). Some of the graduate students who have worked on the experiment include Nicole Lussier (birds and bird-plant networks), Sebastián Aparicio Vera (tree seedling performance), Holden Jones (frogs), Phoebe Reuben (bats and their diseases), and Mareli Sanchez (soil). All of the scientific work performed within the Choconexión Experiment has been permitted by MAATE.
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