How to grow instant fig trees to restore rain forests in Costa Rica

CCSD scientist Leighton Reid and Lyon Arboretum director Rakan Zahawi write about giant fig tree cuttings: how to make them and why some grow better than others.

Choosing the right species to include in a restoration project is a hard choice, but in the economy of nature, some species earn a bigger ROI than others. For example, Pacific sea otters maintain kelp forests by eating sea urchins, and wolves in Yellowstone National Park allow aspen groves to regenerate by scaring away tree-munching elk. These vital creatures are called “keystone species” because they hold ecosystems together, much like the keystone in an arch.

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A keystone and three keystone species. (A) This small keystone holds up an arch in the Shoenberg Temperate House at Missouri Botanical Garden. (B) Sea otters are keystone predators in kelp forests. Photo by Marshal Hedin CC-BY 2.0. (C) Gray Wolves are keystone terrestrial predators. Photo by Gary Kramer USFWS CC-BY-NC 2.0. (D) A keystone fig tree feeding a Knobbed Hornbill in Sulawesi, Indonesia. Photo by T. R. Shankar Raman CC BY-SA 3.0.

Plants can be keystone species too. Around the world there are about 800 species of fig trees, and they hold tropical forests together by providing food for a wide array of animals. On any given day, the busiest tree in a rain forest is likely to be a fig tree with fruits. Monkeys, birds, bats, and others gather at fig trees to eat, and in the process, they deposit seeds of other plant species that they have been carrying in their guts. This chain of events, repeated day after day, often turns the area beneath a fig tree into a hotspot of plant diversity.

A few years ago, we had an idea to plant keystone fig trees in young forests in Costa Rica. We wanted the figs to grow as fast as they could, so instead of planting seedlings, we planted cuttings – big ones. With help from our local collaborator, Juan Abel Rosales, we cut dozens of twelve foot-long branches from eight species of fig trees. We stripped off all of their leaves to keep them from drying out, and then we planted our figs trees in shallow holes.

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Rakan Zahawi (delighted!) poses with a three year-old fig stake.

To our delight, many of the fig trees grew!

The ones that did the best came from a special group, the subgenus Urostigma. Many figs in this group have a unique life strategy. They begin their lives in the top of a tree when their tiny seeds are deposited on a branch by a bird or some other animal. As they grow in the treetop, they send long roots down to the ground, and these roots harden and fuse together, forming a lattice-like trunk. Over time, these figs kill their host trees by taking most of the water, nutrients, and light. They also keep the host tree from growing outwards, giving them the nickname “strangler figs”. Maybe the ability to transform a flimsy, dangling root into a solid trunk is related to these figs being able to grow from cuttings.

To find out how well our planted fig cuttings might survive over the long-term, we also tracked down some fig cuttings that we had planted in 2004. We were happy to learn that out of the trees that survived for their first three years of life, all of them were still thriving a decade later.

Full disclosure: planting large cuttings is not a new idea.  Farmers in many parts of the tropics plant trees this way to create ‘living fences’ – with all of the normal fixings like gates and barbed wire, but with a row of living trees instead of dead posts. The advantages for farmers are many – their fences don’t rot and fall apart (that happens quickly in the tropics); the trees provide shade for cattle; they have a constant source of new fence posts (by cutting off a limb); and in some cases they can feed the young shoots to livestock.

Big cuttings have big benefits for restoration too. Not only are planted trees already several feet tall, you also get to skip the pricey nursery phase, and, most excitingly, cuttings have a tendency to fruit quickly.

Some of our young fig trees are now making fruit, but we will have to wait a bit longer to see whether they start attracting more big animals and whether those animals carry more tree seeds into our young forests. For now, we can say that others who are interested in growing keystone figs for forest restoration may have the best luck by working with the stranglers.

For more information, please take a look at our open access paper on this project in Perspectives in Ecology and Conservation and prior blog posts here, here, and here.

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How to grow an instant fig tree. (A) Remove a long, thin branch segment from an adult tree. The red arrow shows a cut branch. (B) Strip the cuttings of their leaves to keep them from drying out, then carefully transport cuttings so as not to damage cortical tissue. Here, cuttings are padded by a foam mattress. (C) Remove the bark from a ring on the cutting to promote root growth. Here, a ring is being cut about 20 cm (8 in) above the base so that it will be just below the soil surface when planted. (D) Dig a shallow hole and plant the cutting. Be sure that the cutting is firmly planted to prevent it from toppling, but take care not to compact the soil too much around its roots. Photos by Rakan Zahawi.

 

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Seedlings planted for Brazilian forest restoration are not representative of tropical tree biodiversity

A collaborative research project involving MBG’s Center for Conservation and Sustainable Development, the Tropical Silviculture Lab at the University of São Paulo, and the PARTNERS research coordination network highlights important differences between the native tree flora of the Brazilian Atlantic Forest and the species that are widely planted for ecological restoration projects.

The Brazilian Atlantic Forest is a global biodiversity hotspot. This designation denotes two things. First, the Atlantic Forest is exceptionally and uniquely biodiverse. Second, the biodiversity of the Atlantic Forest is exceptionally threatened. This once-vast biome historically stretched from northern Argentina to Brazil’s eastern tip in Rio Grande do Norte, but it is now reduced to about 12% of its original size, and most of what remains exists as small, isolated fragments.

During the past decade, a major, multilateral effort has been undertaken to staunch biodiversity loss by doubling the size of the Atlantic Forest through ecological restoration. The Atlantic Forest Restoration Pact is composed of more than 270 private companies, governments, NGOs, and research organizations. It aims to restore 15 million hectares of Atlantic Forest by 2050.

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The Atlantic Forest biome: a global biodiversity hotspot and the site of the most ambitious tropical forest restoration project on the planet. Map imagery from NASA via Wikimedia Commons.

Atlantic Forest restoration projects are characteristically thorough and well-documented. For example, they often include high diversity plantings more than 80 tree species. Yet until recently there had never been a systematic study to evaluate how well these restoration plantings represented the Atlantic Forest biodiversity they aimed to protect.

Dr. Pedro Brancalion is a professor at the University of São Paulo’s agricultural school in Piracicaba, Brazil, where he co-directs the Tropical Silviculture Lab. Five years ago, he approached me at a meeting of the Society for Ecological Restoration in Madison, Wisconsin, and over a beer he told me about a dataset that he thought could shed light on the how well Atlantic Forest restoration projects were conserving tree biodiversity. The dataset consisted of seedling donation records from the NGO SOS Mata Atlântica. Between 2002 and 2015, the NGO donated more than 14 million tree seedlings to 961 restoration projects. By comparing the species composition in these records to tree species living in mature forests, we could see what elements of biodiversity might be missing and how this could be affecting carbon stocking – an important factor in mitigating global climate change.

Even in high diversity plantings, many of the most threatened tree species were not included.

Last month, Pedro and our collaborative team published a paper in Conservation Letters describing our results. We found that restoration projects in the Atlantic Forest biome had included 416 tree species out of the >2,500 tree species known from mature and old-growth forest fragments. This is an impressive figure, but the team discovered that it reflects a highly biased subsample of the Atlantic Forest tree flora. The most under-represented species were those with large seeds that are dispersed by animals. Animal-dispersed trees make up as much as 89% of tree species in some parts of the Atlantic Forest and include some of the most threatened species.

The reason that large-seeded, animal-dispersed species are being used less often was probably related to the cost and challenges of collecting and growing seeds. Large-seeded, animal-dispersed trees are more expensive to purchase from nurseries than small-seeded or wind-dispersed species. Because they are energetically expensive to produce and are contained within large fruits, trees tend to produce large seeds in relatively low quantities, with just one or a few seeds per fruit. They are generally found in remote forest areas, and seed collectors have to compete for them with seed-eating animals, like peccaries and agoutis. Once large seeds are collected, they also take up considerably more space in storage and production facilities.

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In our analysis of animal-dispersed tree species, seed diameter explained 87% of the variance in seed price. Large seeds like those of Caryocar brasiliense were much more expensive than small ones, like Ficus guaranitica. Grid size: 1 mm. Photos reproduced from C. N. Souza Junior & P. H. S. Brancalion (2016).

The absence of large-seeded, animal-dispersed tree species in restoration plantings has important implications for biodiversity conservation. First, fewer large-seeded trees means less food for large birds, some of which eat mainly large fruits. Second, these species are sometimes overharvested for timber and have difficulty recolonizing forests from which they have been removed. So the fact that large-seeded, animal-dispersed trees are under-represented in restoration projects means that even if the ambitious restoration goals of the Atlantic Forest Restoration Pact are met, the increase in forest cover may not improve dispersal between fragmented populations of the most vulnerable species.

Large-seeded tree species also tend to store carbon more densely than small-seeded species. This tendency is related to large-seeded species growing slowly in the shady understory of the Atlantic Forest and their gradual formation of dense wood, which is rich in carbon. We simulated potential carbon stocking in restored forests and compared it to mature forests, and our results showed that under-representation of large-seeded, animal-dispersed trees could cause a 2.8-10.6% reduction in carbon storage. Based on the current price of carbon, this loss could represent $17-63 USD per hectare in lost carbon credits.

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Many Atlantic Forest restoration projects are quite isolated. A large seed would have a hard time reaching sites like this forest in a sugarcane matrix. Photo by Pedro Brancalion.

Reduced capacity for biodiversity conservation and carbon stocking sounds like bad news, and indeed it is not ideal. However, restoration ecology moves forward by identifying problems and seeking scientifically-based solutions to overcome them. Knowing that large-seeded, animal-dispersed trees are under-represented in restoration plantings means that we can turn our attention to innovative solutions.

For example, new policies could help bridge the gap between Brazil’s exceptional tree biodiversity and the relative paucity of species being used for ecological restoration. One way this could happen would be for the Brazilian government to subsidize the cost of producing large-seeded, animal-dispersed tree seedlings. This could be done through financial incentives or potentially by opening some forest reserves for seed harvesting, to make it easier for collectors to acquire these species. Facilitating uptake by reducing costs would be a carrot. A stick could be to legally mandate some representation of these species in future restoration plantings.

Market solutions may also exist. Based on our calculations, adding more large-seeded, animal-dispersed species to restoration plantings would increase carbon storage and carbon credits, offsetting the cost of the expensive seedlings and creating a net gain of $3-32 USD per hectare.

Banner image: Sterculia striata (Malvaceae). Photo by Mauricio Mercadante. CC BY-NC-SA 2.0.

Drivers of epiphyte recovery in secondary forests in southeastern Brazil

Alex Fernando Mendes is an undergraduate researcher in the Tropical Silviculture Lab at the University of São Paulo, Brazil. He describes his thesis project, undertaken in dozens of forest fragments in the endangered Atlantic Forest biome. Currently, Alex is analyzing his data as a visiting researcher in the Center for Conservation and Sustainable Development.

Historically, intensive agriculture in the Brazilian Atlantic Forest has caused large-scale deforestation of this biome. However, new legal requirements, land exhaustion, and the shifting priorities of farmers have recently allowed forests to regenerate on some formerly farmed lands. Given the unique nature of the Atlantic Forest, its high species endemism, and its potential for providing ecosystem services, the Tropical Silviculture Lab (LASTROP) at the University of São Paulo, coordinated by Prof. Pedro Brancalion and its partners, initiated a project in 2014 to better understand the structure and composition of these new forests.

However, forests aren’t made solely of trees. Among the plant components of a forest, there are others life forms such as epiphytes, lianas, and herbs that contribute to biodiversity and provide food, water, and shelter for many animal species. Epiphytes are plants that use other plants as support. Due to their sensitivity to environmental changes, epiphytes can be used as bioindicators. Therefore, we asked how these plants are doing in these young regenerating forests. And what landscape and local attributes facilitate or hinder their recolonization?

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Epiphyte species found in second-growth forests of the Atlantic Forest – A) Philodendron bipinnatifidum Schott; B) Lepismium houlletianum (Lem.) Barthlott.; C) Ionopsis utricularioides (Sw.) Lindl.; D) Catasetum fimbriatum (E. Morren) Lindl. & Paxton; E) Aechmea bromeliifolia (Rudge) Baker; F) Billbergia sp.

 

To try to answer these questions, we are studying the epiphyte communities in 40 second-growth forests (i.e., forests that were once completely cut down). We are considering three landscape drivers (distance from watercourses, distance from forest edge and forest cover in a 1-km buffer around the remnant) and four local drivers (previous land use, forest age, liana abundance, and tree basal area). We expect that forests close to watercourses would provide the moisture required by epiphytes. We expect to find more epiphytes further from the forest edge since forest cover in more conserved forests may limit their establishment. Since our forests regenerated from abandoned eucalyptus plantation and pastures, we want to check if the non-native eucalyptus could act as a filter preventing epiphytes recolonization. We also expect that older forests and forests with more basal area could house more epiphytes than young forests. Finally, field observations made us wonder if lianas could compete with epiphytes by occupying the same niche.

Of the more than 6,000 phorophytes (trees that could support epiphytes) sampled in these 40 forests we found 398 epiphytes belonging to 21 morphospecies distributed in 4 families (Araceae – 1 species, Bromeliaceae – 14 species, Cactaceae – 5 species, Orchidaceae – 5 species). Only three species, Tillandsia pohliana, Tillandsia tricholepis, and Ionopsis utricularioides, represented more than half (59.5%) of all epiphytes found in second-growth forests. The genus Tillandsia was expected to be abundant in these young forests, since these are disturbance-adapted species that can even be found growing on power lines in cities.

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Epiphytes of the genus Tillandsia (Bromeliaceae) are often found in extreme microenvironments in urban areas (Photos by A. Mendes, 2017).

Our analysis is in progress, but our preliminary observations suggest that forests closer to watercourses and closer to forest edge are more likely to have epiphyte recolonization than forests far from edge and watercourses. Forests regenerated on pastures have more epiphytes than those on abandoned eucalyptus plantation. Our dataset will soon be upgraded with new forest types: conserved and disturbed old-growth forests, and mixed tree plantings for forest restoration, totaling approximately 70 forests with epiphyte samples.

With this research, we hope to find out the local and landscape factors that contribute to epiphyte recolonization in second-growth forests. In practice, this will allow us to locate sites with limited potential for spontaneous colonization of this life form to take actions that promote colonization and establishment, such as introducing individuals. Finally, by identifying epiphytes species that are more sensitive to disturbance, we can focus our reintroduction interventions.

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Small, remnant forests are surrounded by cattle pastures in southern Brazil.

Note: The image of Philodendron bipinnatifidum featured at the top of this post was taken by David Stang. 

Tree islands for tropical forest restoration: the outlook is rosy after 10 years

Planting tree islands has many of the benefits of larger plantations, but entails significantly less cost. Karen Holl (University of California, Santa Cruz), Leighton Reid (Missouri Botanical Garden), and Zak Zahawi (American University of Beirut) describe recent findings on tree seedling recruitment in a long-term experiment in southern Costa Rica.

Over the past few years there have been a growing number of commitments at the global, national and regional scale to restore forests because of their importance to conserve biodiversity, sequester carbon, reduce erosion, and provide goods and services to people. For example, Initiative 20×20, led by the International Union for the Conservation of Nature, aims to restore 20 million hectares of tropical forest by 2020, an area roughly equivalent to the size of Uruguay or Nebraska.

A common strategy to restore forests is to plant trees. But, the big question is: where will the money come from to plant billions of trees when there are so many pressing needs? As restoration ecologists, we started thinking about how we could most efficiently allocate resources to get the best bang for the buck and restore the largest area of forest.

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Trade-offs in forest restoration strategies. Planting fewer trees leaves more to chance and can require more time, but tree plantations are more expensive and leave a bigger ecological footprint. Our study tests an intermediate option, and after 10 years it appears to provide a good balance. Figure modified from Corbin & Holl (2012).

Starting over 10 years ago, we set up a large-scale tropical forest restoration experiment in southern Costa Rica to test two ideas.

First, we tried planting tree “islands”. The idea is to plant groups of trees that attract birds and bats, which disperse most tropical forest tree seeds. The tree canopy also shades out light-demanding grasses that can outcompete tree seedlings. In one experimental treatment, we planted tree islands that covered about 20% of 50 × 50 m plot of former cattle pasture. We compared that to plots where no trees were planted (natural recovery) and to the more intensive (and more typical) restoration strategy of planting trees in rows throughout the plot (plantation).

Second, we asked: is it only possible to restore forest near remnant forests or can you restore forest anywhere in the landscape? This is important information to help guide forest restoration efforts. To do this we set up our entire experiment at 13 sites, some of which were mostly surrounded by agricultural land and some of which were adjacent to the largest remaining forests in the region.

Then we monitored establishment of new tree seedlings in our research plots over a decade. We compared the number of seedlings, number of species, and types of species in the restoration plots with those found in the nearby forest to evaluate how well the forest is recovering.

The tree island planting method not only saves money on buying, planting, and maintaining seedlings, but it also results in a more heterogeneous distribution of trees, so it looks more like a natural forest.

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Profuse tree seedling and sapling recruitment in the understory between two tree islands in southern Costa Rica.

We counted over 6000 tree seedlings, 88% of which have seeds that are dispersed by animals. On average there were many more tree seedlings in the tree island and plantation treatments than in the natural recovery plots. These results suggests that some tree planting helps the forest to recover faster, but that it is not necessary to plant the whole area with trees. The tree island planting method not only saves money on buying, planting, and maintaining seedlings, but it also results in a more heterogeneous distribution of trees, so it looks more like a natural forest.

Even though there were many tree seedlings in the island and plantation plots, on average there were less seedlings of tree species that have big seeds (>0.5 cm/0.2 inches across) compared to mature, reference forests. It seems that the larger-seeded species that are common in mature forests are much slower to colonize restored sites, likely because they are eaten and dispersed by a small number of larger animals, such trogons and agoutis. Many of those dispersers are less likely to visit early successional forest.

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Small frugivores, small seeds. Most of the birds we see in these experimental plots are small-gaped omnivores (e.g., Yellow-bellied Elaenia, Elaenia flavogaster, left), but it usually takes large-gaped species to disperse larger seeds1. The figure at right shows the maximum fruit size that a bird species with a given gape size was able to consume in a cloud forest in central Costa Rica (modified from Wheelwright (1985)). In our experiment, small seeds were ubiquitous, but large seeds were mostly absent.

We were surprised that the amount of forest cover around the experimental plots had a weak effect on the number of seedlings establishing. In other words, isolated plots had just as many tree seedlings as plots right next to old-growth forests. We think that this is likely due to the fact that there are many trees in the agricultural landscape surrounding our plots; these trees include remnant trees, living fence rows, and riparian corridors. Trees in the landscape can serve an important role in both providing sources of seeds and stepping stones for the movement of seed-dispersing fauna. We anticipate that having forest nearby will be more important in future years as these forests build up greater diversity of rare, large-seeded species. Nonetheless, our results suggest that there are good prospects for restoring forests in many locations in this landscape.

Our key finding is that planting tree islands can be a cost-effective way to restore tropical forests at our study site in Costa Rica, but we hasten to note that the strategy should be tested in other locations, particularly areas with fewer forest elements in the surrounding countryside. Our study also demonstrates that tropical forests can recover some species quickly but it will take many decades, if ever, for forests to fully recover. So, preserving existing rain forests is critical to conserve biodiversity and the services they provide to people.

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Diverse tree cover in an agricultural landscape in southern Costa Rica. Remnant trees in pastures, trees along fence rows, and riparian forests provide important sources of flora and fauna to speed up forest recovery.

1See Melo et al. (2009) for an example to the contrary: small-gaped animals dispersing fairly large fruits and seeds.

This work was supported by a grant from the National Science Foundation.

Ecological Restoration in a Changing Biosphere

If you were at the MBG Fall Symposium, we want to hear from you! How did the symposium change your perception of restoration? Send us an email at leighton.reid@mobot.org.

On October 8th, Missouri Botanical Garden hosted its 63rd annual Fall Symposium. This year’s theme was Ecological Restoration in a Changing Biosphere. Author and journalist Paddy Woodworth moderated the day, and seven speakers presented contemporary perspectives on a core challenge in modern restoration ecology. Namely: in the post-COP21 world, when all three UN conventions call for scaling up and mainstreaming of restoration, it is clear that restoration will affect hundreds of millions of hectares – and as many people – over the coming decade. At the same time, we find ourselves in an era of unprecedented change where climate, ecological baselines, and future land-use changes are highly uncertain. This raises the question: What should large-scale restoration look like in the remainder of the 21st century?

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2016 Fall Symposium speakers. From left to right: Peter Wyse Jackson, Curt Meine, Robin Chazdon, James Aronson, Leighton Reid, Pedro Brancalion, Karen Holl, Don Falk, Paddy Woodworth, and Jim Miller. Photo by Andrea Androuais.

Talks during the morning focused on tropical forests, where much of the international restoration dialogue is focused.

  • Leighton Reid (Missouri Botanical Garden) opened with a presentation on restoration longevity – the idea that some restoration projects create ecosystems that persist for more than a century (e.g., Floresta da Tijuca), while other projects fail quickly. Dr. Reid argued that how long restored ecosystems persist is quantifiable, predictable, and manipulable, opening the possibility for more ambitious restoration planning.
  • Robin Chazdon (University of Connecticut and beyond) then spoke about forest landscape restoration, an approach that aims to regain ecological integrity and enhance human well-being in deforested, human-impacted, or degraded forest landscapes. Drawing on a wealth of large-scale studies, Dr. Chazdon made the case that natural forest regeneration is the most ecologically effective and economically feasible approach to forest restoration globally.
  • Karen Holl (University of California Santa Cruz) presented her take on research priorities for forest restoration in the Neotropics. She highlighted that researchers could make an impact by studying forest restoration at larger spatial scales, at longer temporal scales, and in collaboration with stakeholders. Improving information exchange and standardizing monitoring protocols were also among her top priorities. (Graduate students, take note!)
  • Dr. Pedro Brancalion (University of São Paulo) completed the morning session with a TED talk-style discussion of the linkages between science, technology, policy, and best practice in Brazilian Atlantic Forest restoration. Using Thomas Kuhn’s structure of scientific revolutions, Dr. Brancalion argued that restoration ecology is in a crisis period, in part because disciplinary research has predominantly created solutions at smaller spatial scales than the (growing) problems the discipline seeks to address. Perhaps restoration is ripe for a paradigm shift?
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Dr. Pedro Brancalion (right) asks whether restoration ecology is ready for a new paradigm shift, as Paddy Woodworth (left) moderates. Photo by Robin Chazdon.

After lunch, the conversation turned towards a major academic debate in restoration ecology. Has global change outpaced the restoration approach? And is a new approach needed?

  • Curt Meine (The Aldo Leopold Foundation) drew on his long experience in the upper Midwest, and, in particular, his studies of author and environmentalist Aldo Leopold (1887-1948). He argued that Leopold avoided the simple polarities through which some contemporary restoration debates are framed. He viewed nature in a relative way, neither entirely wild, nor entirely domesticated in any given landscape. Although he practiced ecological restoration in some contexts, he also advocated soil conservation and sustainable agriculture – activities motivated by his core values, as expressed in The Land Ethic (1949).
  • James Aronson (Missouri Botanical Garden) followed with an elucidation of the reference ecosystem concept. Reference ecosystems, he noted, help determine the social and ecological vision for a restoration project or program – a critical issue for restoring historic continuity in degraded landscapes. Dr. Aronson described a family of restorative actions for achieving progress towards the reference system, drawing on examples from Jordan and South Africa. He argued we need to look deeper into the past and ponder our choices from many angles as we decide how to do more effective restoration at the landscape and larger scales.
  • Donald Falk (University of Arizona) delivered the keynote address. He painted a disturbing portrait: rapid climate change is driving a massive forest-to-non-forest transition in the southwestern United States. In particular, many ponderosa pine forests will not be able to persist in the future where they have been in the recent past and present. Perhaps restoration ecologists should transition too. Rather than “chasing the ambulance”, maybe we could get out ahead of disasters and ease transitions between stable ecosystem states. Anticipating ecosystem transitions could mitigate the loss of ecosystem functioning that accompanies major climate-driven forest fires, but it would require a shift in restoration thinking. Importantly, Dr. Falk noted that ecosystems do not care what words we use – ecosystems respond to actions.

With moderator Paddy Woodworth’s help, we finished the day with a panel discussion, inviting questions from the audience. Among the thoughts and questions that we were left with:

  • Is ecological restoration more difficult in places with greater population density?
  • Should restoration focus on policy, economic, or cultural motivations for engaging people?
  • Are values a better guide for land management than ecological history? Are the two complementary?
  • How can the reference ecosystem concept accommodate rapid biome changes, as we are seeing in the Southwestern USA?
  • What is the way forward to mainstream serious, multisectorial monitoring and evaluation with all these new factors to consider? Who will fund it?
  • To what extent can we move from restoring degraded ecosystems to avoiding degradation in the first place?
  • Can forest landscape restoration and natural forest regeneration bridge the gap between small-scale, past restoration experience and present, large-scale restoration needs?
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PhD candidates Ricardo Cesar (University of São Paulo) and Leland Werdan (University of Minnesota) compare notes on seedling functional traits in dry tropical forest restoration. Leland was the recipient of the annual Delzie Demaree award. Photo by Robin Chazdon.

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More than 150 people registered for the symposium. They came from three continents, five countries, and seven US states.

Epiphyte restoration in Brazil’s Atlantic Forest

CCSD restoration ecologist and PARTNERS member Leighton Reid spent 10 days collaborating with scientists and students in the Tropical Silviculture Lab (LASTROP) at the University of São Paulo. Epiphytes were a central theme of the visit.

Vascular epiphytes are plants that live non-parasitically on other plants. Readers from the tropics will be quite familiar with some epiphytes, like the ubiquitous Tillandsia of Neotropical powerlines, but temperate zoners will have seen many epiphytes as well, at the florist, the botanical garden, and the mall. These plants are incredibly diverse; by one estimate, epiphytes make up 9% of all vascular plants worldwide. But epiphytes also face serious challenges in today’s world. Habitat loss and overharvesting threaten some epiphyte species with extinction. Many epiphytes also have a hard time recolonizing new habitat in regenerating forests, but new studies on epiphyte restoration could help.

I spent the past 10 days in the State of São Paulo learning about epiphyte ecology, conservation, and restoration from students and scientists at the University of São Paulo’s College of Agriculture (Escola Superior de Agricultura Luiz de Queiroz). This part of Brazil was once covered in semideciduous tropical and subtropical forests, which hosted about 150 vascular epiphyte species. Today, only ~15% of the forest remains, but there is a large effort underway to restore 15 million hectares (nearly 58,000 square miles) of it by 2050.

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ESALQ maintains shade house with more than 3,000 orchids, including (A) Cattleya loddigesii, (B) C. forbesii, and (C) Arpophyllum giganteum.

Frederico Domene is a doctoral student studying epiphyte reintroduction in restored Atlantic Forest. Like his advisor, Pedro Brancalion, Fred’s interest in epiphyte restoration stems from a passion for orchids. He grows a variety of them at his house in Piracicaba, preferring true species over horticultural varieties.

Fred picked me up in his black pickup, “mamangava”, and took me on a tour of several tree plantations where he has been developing methods for reestablishing populations of epiphytic orchids, bromeliads, cacti, and aroids. Fred’s basic procedure involves collecting epiphyte seeds (or purchasing small plants, in the case of orchids), growing them out in a nursery, and then attaching them to trees using twine or plastic. He started his work in 2010 and has been monitoring his plants, and reintroducing new plants, every year since. He uses a ladder to put the orchids up high, out of easy reach for would-be poachers.

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Atlantic Forest restoration plantations. Left: 60-year old plantation along the Rio Piracicaba near Rio Claro. Right: 12-year old plantation at the Anhembi Forest Science Experimental Station. The older restoration site had considerably more naturally recolonizing epiphytes than the younger site.

Late August is mid-winter in São Paulo, and while it doesn’t get particularly cold, it is quite dry. The restoration plantations were crunchy with desiccated leaves and twigs. These are harsh conditions for epiphytes, which do not have the luxury of soil to buffer to their roots from the sunlight and dry air. Some of Fred’s epiphytes have withered and died, especially during a 100-year drought in 2012. But others are thriving, thanks to special adaptations, such as the velamen of orchid roots, which wicks up rainwater when it drips down the tree trunk during storms. Many individuals have started fruiting and flowering, a good sign for the future viability of these reintroduced populations.

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Epiphyte reintroductions in restoration plantations. (A) A reintroduced festoon of bromeliads, orchids, and cacti. (B) A fruit-bearing orchid (Cattleya forbesii), six years after reintroduction. (C) This reintroduced cactus (Epiphyllum phyllanthus) seemed to grow better in tree forks than on vertical stems, as did an aroid, (D) Philodendron bipinnatifidum. (E) Two tiny cacti have germinated in this direct seeding experiment, using seeds enrobed in paper discs. (F) Even where epiphytes have dessicated and died, experimental infrastructure continues to enhance epiphyte development; here a small bromeliad (Tillandsia recurvata) uses a piece of natural twine as a foothold.

To identify the key challenges for epiphyte restoration, it is also important to study epiphyte recolonization in naturally regenerating forests. Alex Mendes, an undergraduate researcher at ESALQ, is doing just that. On an unseasonably rainy morning, Alex, Fred, and I visited three regenerating forests near the sugar town of Rio Claro. We ducked under barbed wire fences and wandered through low, dense vegetation where Alex is systematically searching for vascular epiphytes. Two forests had rather few epiphytes – mostly generalist bromeliads – but one forest had a high density of orchids, which happened to be flowering spectacularly on the day we visited. Based on historical aerial photos, Alex knows that these three forests are at least 20 years old. They are part of a network of 75 sites that he will ultimately search for epiphytes. By the end of his undergraduate program, Alex hopes to be able to predict where epiphyte communities will regenerate on their own, and where they will need more assistance.

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This secondary forest near Rio Claro might have felt like your average overgrown Psidium guajava patch had it not been  decorated with dozens of Ionopsis sp. orchids.

These are early days for learning about epiphyte restoration, and there is still a lot of work to be done. The projects that I visited in Brazil are making headway, complementing our research in Costa Rica. It remains to be seen under what circumstances epiphyte reintroductions will be most successful. Perhaps an even more important issue will be convincing funding agencies and land managers to think beyond trees.

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Fred Domene and Alex Mendes are making strides in the ecology of epiphyte reintroductions and community assembly. Here, they pose with a reintroduced bromeliad (Billbergia zebrina) at Anhembi experimental station.

Fig Stakes: Shoreline Restoration for a Costa más Rica

Andres Santana is the graduate program coordinator at the Organization for Tropical Studies. During a recent fieldtrip in southern Costa Rica, he and CCSD restoration ecologist Leighton Reid compared notes on using fig stakes for ecological restoration.

Tropical beaches are many things to many people. To plants, beaches are hot, sandy, and salty – complicating their restoration.

Costa Rica has 1228 km (763 mi) of coast line – including 1016 km on the Pacific side and 212 km on the Caribbean. Along Costa Rica’s northern Pacific coast, the beach forms the natural edge of the dry forest. Farther south the adjacent forest is more humid. Giant trees, 40 m or more in height, grow right up to the high tide mark, particularly along the Caribbean.

But as with so many tropical ecosystems, Costa Rica’s coastal forests have been subject to human impacts. Many shoreline forests were cleared for cattle ranching, and exotic grasses were introduced as forage. Some of these grasses are fierce competitors and prevent tree seedlings from establishing, even long after the pastures have been abandoned.

Playa Hermosa Antes y Despues

Playa Hermosa, before (left) and after (right) planting 2-m long cuttings of a coastal fig species (Ficus goldmannii).

In 2009, a small non-profit organization, Costas Verdes, was formed to restore coastal forests along degraded shorelines, particularly wildlife refuges. The restoration work was initially challenging; tree seedlings were hard to establish along the coast because of the harsh environment – high temperatures and salinity and lack of freshwater were among the most significant obstacles. Not to mention the invasive cattle forage grasses.

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Coastal restoration at Playa Hermosa

Playa Hermosa, a surfing destination on the Central Pacific coast, was among the most heavily deforested project sites. This area, part of a wetland and river estuary, was declared a national wildlife refuge in 1998. By 2009, very little forest had naturally regenerated. This led Costas Verdes to implement a restoration project at this beach. Planting plots were established where invasive grass was removed. In other areas, grasses left intact, as a comparison. It quickly became evident that tree seedlings were outcompeted by the grass. Those in the cleared plots grew better, but they still faced the other coastal habitat challenges.

Some native trees are resistant to hot substrates and high salinity, but these species were not available in tree nurseries, most of which focused on ornamental species. This meant that seedlings needed to come from locally collected and germinated seeds. We realized that this would take time to get going. Tree seedlings under 50 cm rarely survive, even if they have the proper coastal adaptations.

To accelerate the restoration, we decided to use tree cuttings rather than growing seedlings from seed. A colleague suggested Ficus goldmannii as a candidate species, so in 2011 we conducted a planting trial. We planted 225 2-m long cuttings. Of these, 195 (87%) survived their first year. By the second year all 195 survivors had become established and were quickly providing canopy cover and lowering the temperature of the sand.

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An established fig stake with a dense canopy. Note the weak, patchy grass below it.

Once fig stakes created some canopy cover, we brought in other tree species – mostly from the coastal tree nursery that we created. Shade from the fig canopy also began to inhibit the invasive grasses, which require high sunlight to photosynthesize efficiently. Reduced competition with these grasses allowed other tree seedling species to survive.

In this instance Ficus cuttings turned out to be useful in promoting restoration. We have since used cuttings for other plots with similar success.

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Coastal trees and shrubs growing below established fig cuttings at Playa Hermosa.