Little known side of Hong Kong: Conservation and Restoration work at Kadoorie Farm and Botanic Garden (KFBG)

James and Thibaud Aronson made a stop in Hong Kong recently, and post a report on what’s going on restoration-wise at the 60-year old Kadoorie Farm and Botanic Gardens.

After three weeks in New Zealand – about which we will report in our next two posts – we stopped recently in Hong Kong to visit the Kadoorie Farm and Botanic Garden (KFBG), which has just celebrated its 60th anniversary. Most visitors to Hong Kong never leave the city center, which has the second highest concentration of skyscrapers in the world and rivals London and New York for shopping, but also as a global hub for finance, trading, and marketing. But, we were lucky: through our friend Kingsley Dixon we had an introduction to Dr. Gunter Fischer, Head of the Flora Conservation Department at KFBG. Dr. Fischer came to Hong Kong from Austria, 7 years ago, and now oversees the vast – and gorgeous – botanic garden, the herbarium, the genetic and ecology laboratories and the various restoration and native plant recovery programs at the KFBG, which is the result of an exemplary public sector-private sector partnership. Behind the scenes, a key component is the large on-site tree nursery and enormous amounts of effort devoted to seed collecting and plantations of mother plant collections of rare native tree species for seed production. “In a changing world, resilience comes from diversity”, as Gunter so nicely puts it.

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Ms. Chung Yick Kwan, an employee of the garden working in the KFBG tree nursery, handling one of the many rare native species propagated here.

Other departments at KFBG include the Sustainable Living and Agriculture, Fauna Conservation, Kadoorie Conservation China, and Education. Activities are devoted to developing and demonstrating sustainable small-scale farming methods for food production in South China, including new methods such as permaculture and traditional Chinese methods that have been lost or abandoned during the Chinese cultural revolution. There is also an extensive rehabilitation program for wild animals, notably many rare and endangered turtles, mammals, and birds that were seized by Hong Kong customs or delivered by animal rescue organizations.

All of these activities stem naturally from the original raison d’être of the organization. When Sir Horace and his brother Lord Lawrence Kadoorie founded the Farm 60 years ago, their goal was to help Chinese immigrants get established as small farmers.

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Sir Horace and Lord Lawrence Kadoorie – the founders of KFBG. (Photo: KFBG archives)

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Text of one of the guiding principles of the charity work of KFBG in the early 1950s, which is still valid in the 21st century (NB. In the 1950s KFBG was called KAAA, Kadoorie Agricultural Aid Association). (Photo: KFBG archives)

To this day, the Kadoorie Foundation is the main funding source of the KFBG. But with vastly greater affluence in Hong Kong today, since the mid-1990s, a decision was made to transform the property into a world-class education and conservation center with a botanic garden at its heart. The conservation work comprises numerous projects in Hong Kong and mainland China but also parts of Southeast Asia, such as poorly explored regions of Laos and Cambodia.

Originally, Hong Kong was covered in tropical and subtropical forest, but it was completely deforested after the British took over in 1841; visitors in the 19th and early 20th century called Hong Kong a “barren rock”. As a result of centuries of cultivation with crops such as rice and tea, and ongoing urbanization in combination with more and more exhausted soils, many mountain slopes were left to their fate, completely denuded of any vegetation ongoing soil erosion, and high run-off during the annual monsoon seasons caused landslides and wreaked havoc.

Starting in the 1880s, successive governments undertook massive afforestation programs, as documented by the eminent ecologist Richard Corlett. However, during the World War II Japanese occupation of Hong Kong, most of the recently recovered forests were burned or devastated by harvesting of fuel wood.

After WWII, secondary forests began to recover, but of the 450 native tree species, only ca. 100 regenerated naturally, and the other species carry on sadly towards extinction. Moreover, there are huge problems with introduced grasses, many of which carry fire far better than anyone would like.

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Upper area of KFBG’s restoration site devastated by a fire in 2004. (Photo: Dr. Billy Hau)

Thus the challenges for conservation and restoration are enormous. Indeed, the same is true at the regional scale. As Gunter told us, “most of the forests of South China have been trashed”; only tiny fragments of primary forest remain, and very little work on restoration of the original forest is going on. Since he arrived at KFBG, over 6 years ago, Gunter has done remarkable things in the botanic garden portion of the 159 hectare property, located on a steep slope of Tai Mo Shan, the highest point in Hong Kong (957 m or 3140 ft), including the launch of an ambitious restoration program on the recovering wilderness portion of the property that few visitors see. Rather than full coverage, a tree island, or assisted nucleation approach is taken, similar to that used in on-going experiments in Costa Rica, which Leighton Reid posted on last November.

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Core area of the 15 hectare (42 acre) experiment restoration site at KFBG, showing tree island plantings of 2015 and 2016, with various soil preparation techniques and tree guards being tested. (Photo : Gunter Fischer)

The focus is largely scientific and conservation-oriented, given that most of the flora of Hong Kong is highly endangered. However, horticulture and arboriculture are as important as ecology here, Gunter assures us – an observation that jives well with the Missouri Botanical Garden’s approach to restoration as well. For example, Gunter and his colleagues not only plant ten thousand trees on average each year, all produced in the experimental KFBG nursery, they also prune and shape the trees they’ve planted to encourage upward growth rather than low shrubby formatting, which is what often happens with many trees after planting.

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Structurally pruned Quercus edithiae, a rare canopy tree in South China.

A large proportion of the tree planting budget is devoted to plastic cylinders (tree guards/shelters) to protect tree saplings from barking deer and wild boar, but also from harsh climatic conditions.

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Tree guards used to protect seedlings on a ridge from strong desiccating winds.

The KFBG restoration team also makes a big effort to study soil improvement techniques that will compensate for degraded soils and improve survival and early growth of the planted trees. One of the most interesting components of this experimental work concerns the use of Biochar prepared on site, by slowly heating wood in closed containers with almost no air. Much of the wood comes from stems and trunks of intentionally introduced and now invasive fast-growing trees, such as the appropriately named Acacia confusa, that are gradually being removed from the property. This approach to invasive woody weeds has great potential in many parts of the world and should receive a lot more attention and investment.

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Invasive trees and those deemed hazardous to human safety are continuously removed and replaced with native species. The wood is used to prepare biochar.

Clearly, KFBG is one of the bright spots of plant and animal conservation, and ecological restoration in Asia today.

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Native animals such as this bamboo pit viper (Trimeresurus stejnegeri) are recolonising the restoration site. (Photo: Gunter Fischer)

For more information, see the recent article published by Gunter and his colleague Jinlong Zhang. Also, if you’re travelling to Hong Kong, be sure to stop by. Even if you don’t trek to the higher slopes to see restoration work-in-progress, the Botanic Garden is also full of interesting natural and cultural sights and stories too, such as these elevated pigeon hotels. And how many botanical gardens occasionally have to close a road because a massive python is stretched right across it, digesting a deer for a week!

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Dragon boat pigeon hotel on the KFBG grounds.

And there is the museum, theme gardens such as the Gloria Barretto orchid sanctuary, and lush forest gardens that appear to be native forest fragments but in fact are tropical gardens providing an exhilarating experience for thousands of visitors each month just a few miles from downtown Hong Kong.

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Montane streamside forest garden with trees covered in epiphytic ferns.

 

 

Vascular epiphyte restoration using bromeliad transplants in Southern Costa Rica

Estefania Fernandez is a Bascom Fellow who recently finished her master’s thesis at the University of Montpelier, France. Last year, Estefania wrote about her preliminary results on tropical forest restoration and vascular epiphyte reintroductions in Costa Rica. Here, she describes the final results, recently published in Restoration Ecology.

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A transplanted bromeliad, Aechmea dactylina flowering in a 10-year old tree plantation.

Vascular epiphytes are plants that germinate and root on other plants without taking their nourishment from their host plant, and they represent 50% of the flora in some tropical forests and 9% of all vascular plants worldwide. If you are a plant lover, then you most likely have one or several vascular epiphytes in your house. Some of the most appreciated horticultural families include orchids (Orchidaceae), aroids (Araceae), and bromeliads (Bromeliaceae).

Vascular epiphytes also play key roles in our ecosystems. They are crucial to forest water and mineral recycling as they intercept rainfall and prevent rapid run-off and nutrient leaching. Vascular epiphytes are also exceptional microhabitats where invertebrate communities find refugia and birds and arboreal mammals forage.

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Transplanted individual of Werauhia gladioliflora

Despite their importance in forest ecosystems, vascular epiphytes are rarely taken into account in forest restoration. This is problematic because vascular epiphytes are often among the slowest plants to recolonize regenerating forests.

In 2015-2016, I tested whether transplanting epiphytes into young restoration sites could be a viable strategy to accelerate their reestablishment. I used a bromeliad for my experiment, Werauhia gladioliflora (H. Wendl.) J.R. Grant, which was common in remnant forest but had not been found during epiphyte surveys in nearby restoration areas. In March-June 2015, I transplanted 60 bromeliads into three restoration plantations near Las Cruces Biological Station in southern Costa Rica. I revisited the sites in January-February 2016, nine months after transplantation, to monitor survival and arthropod recolonization.

Happily, over 75% bromeliads survived and the number of arthropods on branches with bromeliads was seven times greater than in branches without bromeliads. Additionally, I observed that bromeliads buffered the local microclimate; during the driest and hottest times of the day, the interior of the bromeliads was moister and cooler than ambient air.

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Transplanted individuals of Werauhia gladioliflora (left) hosted considerably more arthropods in their rosettes than could be found on the stems of trees that had not received a transplant. GN, JG, and MM are three study sites near Las Cruces Biological Station in southern Costa Rica. Photo by Dave Janas.

Restoring arboreal refugia

My research suggests that transplanting fallen epiphytes onto trees in restored sites contributes to the recovery of vascular epiphyte diversity in these ecosystems and has the additional benefits of bringing back arthropod diversity to these sites. Epiphytes, and specifically “tank” epiphytes that retain water in their rosettes, help stabilize microclimatic conditions, a critical function in light of climate change, which may put arboreal communities at special risk. Indeed, the body temperature of many animals such as invertebrates entirely depends on ambient temperatures but rising temperatures could push arboreal animal communities to the ground. Epiphytes offer ideal refugia from high temperatures and drought and their presence in tree canopies and understory is critical to preserve arboreal animal communities. Transplanting other epiphyte families or even entire epiphyte communities found on fallen branches could be tested in the future to broaden this strategy.

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Estefania inspects a flowering individual of an Aechmea dactylina transplant

 

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.

Reforesting with Figs

 Benjamin E. Smith is a Ph.D. student at George Washington University. He recently completed a field ecology course with the Organization for Tropical Studies in Costa Rica, where he worked with CCSD scientist Leighton Reid. When he’s not coring fig trees in Costa Rica, Benjamin studies plant-herbivore interactions in American chestnut.

It was my recent privilege to spend a week at Las Cruces Biological Station in Costa Rica where I learned about some amazing properties of fig trees.

The genus Ficus contains over 800 species, which can be found in the tropical to warm temperate regions throughout the world. Where they occur, figs are vital components of their local ecosystems because they provide high quality fruits for many animals. Animals attracted by the delicious figs often carry other plants’ seeds in their digestive tracks and subsequently deposit them below the fruiting fig tree. This can lead to patches of forest with especially high plant diversity.

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Two individuals of Ficus obtusifolia demonstrating the strangler lifestyle (left) and the free-standing lifestyle (right). The individual on the left has overtaken one host tree and is reaching out to claim another. The individual on the right was planted (either by humans or birds) in a fence row.

Some fig species have the ability to resprout roots, branches, and leaves from broken limbs – an adaptation that would be useful in an ecosystem with frequent disturbances, like hurricanes or landslides. Rural people have been utilizing this incredible feat of nature to create living fences for hundreds of years; they simply cut branches from a tree and plant them. Plant a large enough branch, and you’ve got an instant tree.

Instant fruiting trees could be a practical tool for ecological restoration, and there is currently an experiment underway to test this idea. But not all fig species can resprout from cuttings, so in order for this tool to be useful outside of southern Costa Rica, it would be helpful to know which species will resprout and which will not.

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A healthy cutting of Ficus colubrinae. This instant tree was planted in May 2015.

Does wood density predict resprouting in figs?

We sought a way to determine whether a particular fig species would be able to resprout from a limb cutting before actually cutting apart large trees. This would mean only trees whose cuttings will survive would be used and trees that can’t resprout could be left undamaged.

We believed that wood density would be a good measure to figure this out. Wood density can tell you a lot about a tree’s life history strategy. Is it a hard tree that will resist snapping in a stiff breeze? Or is it a softer tree that might break, but then resprout?

To test this, we took core samples from seven fig species and headed to the lab. After a couple days of measurements, we had our data.

Methods

(A) OTS student Orlando Acevedo Charry extracts a core from a Ficus colubrinae. (B) Cores were cut into small pieces. We measured the mass of the water that each segment displaced to determine the wood’s green volume. (C) Next, samples were placed in a drying oven at 106° C for 24 hours. Finally, we measured the mass of the dried samples and divided by the green volume to determine wood density.

The fig species we tested turned out to have pretty similar wood densities. Also, the slight variations in wood density did not correlate with trees’ resprouting abilities. This initially came as a big disappointment, but after taking a second look at our data we started to see a trend that may actually be much cooler.

Results

Wood density was a poor predictor of resprouting capacity (measured by tallying fig cuttings that were planted in April-May 2015; Left), but strangler figs in the subgenus Urostigma performed much better than two free-standing species in subgenus Pharmacosycea.

Fig species come in a variety of forms. Some are rather conventional free-standing trees that grow from the ground up, but others start as seedlings high in the canopy of another tree and send roots down to the ground, gradually strangling their host. Still others are shrubs, climbers, and epiphytes. We found that stakes cut from strangling figs, the ones that initially rely on a host tree, were much more likely to resprout than stakes cut from free-standing fig species. If this holds true, no measurements will be needed in the future. People around the world may be able to tell if a tree will likely sprout from a cutting just by the way it grows.

Hill of Honey: Forest Recovery on Madagascar’s Central Highlands

This post was co-written by Leighton Reid and Chris Birkinshaw after a three-day field trip in the tampoketsa with Cyprien Mandriamanana and Jeannie Raharimampionona.

A narrow, paved road winds north from Antananarivo through a high, windswept plain. It is the wet season, and the hills are green and close-cropped, but in the long dry season the landscape burns black. Orange rivers wind through the valleys, muddied by massive erosion. Here and there are thin strips of riparian forest, chock full of endemic species.

The biggest chunk of remaining forest is Ambohitantely, Malagasy for “hill of honey”. Ambohitantely encompasses 1,800 ha of humid forest (about three times the size of Saint Louis’s Forest Park). We visited the reserve to observe natural forest recovery in one of the few places it can still be seen on Madagascar’s Central Highlands.

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Ambohitantely: the last large tract of forest on Madagascar’s Central Highlands. Ten kilometers to the northwest is Ankafobe, a much smaller forest fragment managed by a local community with assistance from Missouri Botanical Garden.

Forest transition feedback

Why is forest recovery so rare in the Malagasy highlands? Madagascar’s Central Highlands are currently undergoing a complete ecological transition, from forest and wooded savanna to grassland. The degradation cycle often starts when people cut forest trees to extract wood for timber and charcoal production. Small-scale cutting opens the canopy, dries the forest floor, and creates debris, all of which increase forest vulnerability to annual wildfires that sweep across the grasslands during the eight month dry season. C4 grasses quickly colonize the burned land, inhibiting forest recovery, and creating ideal conditions for future fires. The reason that Ambohitantely has natural forest recovery for us to observe is because reserve staff maintain a wide fire break for more than thirty kilometers around the reserve.

Our guide at Ambohitantely took us on a hike through several areas where forest had once been cleared and burned but where fire had been excluded for 15 or 25 years, allowing the forest to begin to recover. Frankly, the vegetation was uninspiring. Low shrubs and forbs were scattered through a matrix of C4 grass (mostly Aristida), but trees and tree seedlings were nowhere to be seen outside of the forest (where they were abundant). By tropical forest standards, this looked slow. But for natural forest recovery on the Central Highlands, it’s hard to imagine a better situation than being protected from fire and immediately adjacent to the largest remaining tract of forest.

Ambohitantely forest edge

After 25 years of recovery, forest edges were sharp. Tree seedlings were almost totally restricted to forest, and grasses dominated the ground layer just outside.

Our main interest in Ambohitantely was to compare natural forest recovery there to our observations at another forest fragment, Ankafobe, 10 km northwest. For the last decade, MBG has partnered with a local community to preserve a thin, riparian forest containing several critically endangered plant species. Community members constructed a fire break and have begun to restore the surrounding hillsides by turning over the orange clay and planting fast-growing legumes to develop the soil.

Ankafobe hillside with Schizolaena

A degraded hillside at Ankafobe; the remnant forest is down the hill to the right, near the edge of the photo. The tree at the top of the hill is Schizolaena tampoketsana, a critically endangered microendemic in an endemic Malagasy plant family (Sarcolaenaceae). It is a remnant forest tree that likely escaped repeated fires by being nestled in a deep, protective gully. The multi-stemmed shrub in the foreground is actually a large tree species, Brexia montana, which has likely resprouted many times from a well-developed root system.

Some of our comparative observations were promising. We were happy to find examples at Ambohitantely where recovering land dominated by heather and blueberry seemed to have continued developing into a more diverse thicket, including Nuxia capitata, Psiadia altissima, and Razafimandimbisonia minor. At Ankafobe, we had worried that the heather growing in some areas signified poor soil conditions and possibly arrested development.

Overall our visit left us with more questions than answers. We hope to answer at least a couple of them over the coming years.

  • Why is natural forest recovery so slow on the Central Highlands?
  • Has it always been this slow?
  • Are Malagasy tree species poor pioneers because of their long, relatively stable evolutionary ecological history?
  • Is there any way to make Malagasy trees grow any faster on the degraded grasslands?1
  • Are the fire-stoking C4 grasses introduced from east Africa rather than being native species?
  • If so, when?
  • Is the soil too far gone to ever recover?
  • How important were now-extinct seed dispersers and grazers, like 200-kg lemurs and elephant birds?
Ambohitantely cloud cover

Although Ambohitantely is the only remnant forest fragment of any size, we learned recently that it may not be a perfect reference system for Ankafobe. For one thing, Ambohitantely is slightly higher and farther east, which results in considerably greater cloud cover during the dry season. This probably ameliorates the harsh conditions outside of the forest, at least a little. Shown here is cloud frequency from May – October, taken from NOAA MODIS satellite imagery. Thanks, Michael Douglas!

References

Goodman, S.M. & Jungers, W.L. 2014. Extinct Madagascar: Picturing the Island’s Past. University of Chicago Press, Chicago, IL.

Pareliussen, I., Olsson, E.G.A. & Armbruster, W.S. 2006. Factors Limiting the Survival of Native Tree Seedlings Used in Conservation Efforts at the Edges of Forest Fragments in Upland Madagascar. Restoration Ecology 14: 196-203.

1Two datasets (one from our team and one from Pareliussen et al’s [2006]) suggest that NPK fertilizer, even in relatively small doses, reduces native tree seedling performance. It is unclear whether this is because of toxicity (a direct effect) or because other plants, like shrubs, are better able to utilize the nutrient pulse and then compete more strongly against the native tree seedlings (an indirect effect).

El Niño’d: tropical field research when climate won’t sit still

Steve Roels is a PhD candidate in the Department of Integrative Biology at Michigan State University. His research asks how trophic cascades interact with tropical forest restoration. When not in Panama, he enjoys documenting biodiversity and restoring native vegetation on his own 6.2 acres of Michigan.

Tropical field biology has a lot of uncertainty built into it. The scientific community is still barely scratching the surface of tropical biodiversity and the immense complexity of biotic interactions (relationships between organisms). Biologists, myself included, often get lulled into thinking of the tropical climate as a stable abiotic backdrop that lies behind the great drama of biotic interactions. But what happens when those abiotic conditions change abruptly and dramatically?

The current El Niño event in the Pacific is now regarded by meteorologists as one of, if not the, strongest El Niño events ever recorded. The North American media understandably focuses on how El Niños affect our continent; usually wetter West Coast winters and dryer, warmer Midwest winters. What many North Americans don’t realize is that El Niño events have their most profound effects on Pacific countries in the tropics.

El Niños are one extreme of a much larger climate pattern, the Southern Oscillation. The El Niño-Southern Oscillation (ENSO) is an erratic seesaw of Pacific surface water temperatures from warm to cool (La Niña events) and back again. Temperature swings from one extreme to the other occur every few years (on average about 5) and “the switch” is often flipped very abruptly, shifting ocean currents, air pressure, and precipitation throughout the eastern Pacific. It is important to keep in mind that ENSO events are not “bad” per se, just different, and that creates biological winners and losers.

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Strong El Niño conditions in the eastern Pacific during my field season. Image from: www.ncdc.noaa.gov.

In central Panama, where I research bird communities in forest restorations, El Niño conditions generally bring warm coastal waters and drought. I say “generally” because each El Niño is like a snowflake—there are some basic patterns, but every event is unique. This El Niño is sticking to the pattern: central Panama is currently experiencing a severe drought and creating headaches for many of my colleagues at the Smithsonian Tropical Research Institute (STRI). The drought has played havoc with the frog biologists, who are waiting for mating frogs, who have, in turn, often been waiting for rain. Coral researchers are scrambling as abnormally warm waters cause coral bleaching. However, some scientists view this El Niño as an opportunity because it could be considered a proxy for future climate. The El Niño is compounding the warming effects of global climate change, putting 2015 on track to be the warmest year on record. A friend of mine who studies tree physiology and water use in forest restorations says she is getting great data. After all, a key challenge for restoration ecology is deciding what we restore to. An ecosystem that tries to match what was formerly present? Or one that will continue to thrive in an uncertain future?

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The Agua Salud restoration site. The blocks of vegetation in the landscape are different experimental tree planting treatments. Lake Gatun, part of the Panama Canal, lies in the haze on the horizon. Lake levels are anticipated to drop to record lows this dry season.

The effects of current El Niño on my own research are difficult to assess. I study trophic cascades (basically, ripples in food webs) at STRI’s Agua Salud forest restoration project, especially focusing on birds, insects, and trees. I conducted an experiment this past July-August, which is normally the heart of the wet season, but was instead a historic drought. How this drought effected tree growth, insect populations, and bird behavior—all components of my study—is hard to say. Prior research on ENSO effects on trophic relationships is limited (it’s hard to plan research around an unpredictable and irregular event!) but some long-term studies have found large ENSO effects on food webs in Panama and Chile.

When I returned to the United States after my field season and talked with my research advisor about the uncertainty the El Niño brought to my study, she said, “You’re going to hate me for saying it…” I replied, “I already know what you’re going to say.” Maybe I need to do the experiment again next year.