Smithsonian Tropical Research Institute

Ancon, Panama

Smithsonian Tropical Research Institute

Ancon, Panama

The Smithsonian Tropical Research Institute in Panama, the only bureau of the Smithsonian Institution based outside of the United States, is dedicated to understanding biological diversity. What began in 1923 as a small field station on Barro Colorado Island in the Panama Canal Zone has developed into one of the world's leading research institutions. STRI’s facilities provide a unique opportunity for long-term ecological studies in the tropics, and are used extensively by some 600 visiting scientists from academic and research institutions in the United States and around the world every year. The work of resident scientists has allowed STRI to better understand tropical habitats and has trained hundreds of tropical biologists. Wikipedia.

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News Article | April 17, 2017
Site: www.eurekalert.org

Whales from both poles migrate long distances to breed in tropical waters. Smithsonian scientist Hector M. Guzman and Fernando Félix at the Salinas Whale Museum in Ecuador, tagged 47 humpbacks with satellite transmitters to understand how the humpbacks' Southeastern Pacific population moves within breeding areas. "Our work fills an informational void: we've known these whales move between feeding areas and breeding areas, but we hadn't characterized their movements, and we couldn't exactly pinpoint the range of the breeding area," said Guzman, marine ecologist at the Smithsonian Tropical Research Institute (STRI) in Panama. "Now we know that individuals move between countries within the breeding season and that their entire breeding area extends approximately 2,600 kilometers of non-straight coastline from Costa Rica to Peru." For years, scientists have identified individual humpback whales (Megaptera novaeangliae) based on their unique fluke and dorsal fin patterns. In this study funded by STRI, Panama's National Office of Science and Technology, the Candeo Fund at the International Community Foundation and the Whale Museum, 25 whales were satellite tagged in Panama and 22 in Ecuador between 2009 and 2015 according to methods approved by the Smithsonian's Animal Care and Use Committee (IACUC). On average, tags transmitted for about two weeks, although one tag lasted for 69 days during which a mother whale swam nearly 6,000 kilometers. Information from the 37 tags that transmitted for at least 1 day revealed the movements of 23 mothers accompanied by newborn calves and 14 unsexed animals. "Thanks to new spatial models that were used to evaluate the movement of the whales, we could differentiate behaviors and gauge the speed of the whales during their reproductive and migratory periods," Félix said. Part of the Southeast Pacific humpback whale population breeds in Panama's Las Perlas Archipelago and in the Gulf of Guayaquil in Ecuador. The roughly 60,000 square kilometers of home range of the group in Panama was about twice the size of the home range of the group breeding in Ecuador--about 26,000 square kilometers, which means whales are not randomly distributed but show site fidelity. Whales tended to spend time in short-range movement, alternating with long-range, faster, directed movement. Mothers spent more time closer to shore than other tagged, unsexed individuals. Both types of whales swam into deeper waters mainly during migration. Mothers in Panamanian waters spent much more time in long-range movements than did mothers in Ecuadorian waters, perhaps because they were shifting from a nursing phase to a migratory phase. Guzman and Félix suggest that the overlap between breeding individuals exhibiting short-range movements and non-breeding individuals exhibiting long-range movements at the same sites creates confusion about how many animals are breeding at a given time. This is especially true in Ecuador because individuals breeding in Colombia, Panama and Costa Rica pass through on North-South migrations. Humpback whales were once hunted nearly to extinction. Since the 1966 hunting moratorium, populations rebounded to more than 80,000 humpback whales in the world. But as human populations grow, the number of oil and gas terminals, offshore platforms, new ports and marinas is on the rise and coastal pollution, and traditional activities such as fishing and maritime traffic are intensifying. "Our breeding range analyses provided the first-ever insight at such a fine scale on the distribution of humpbacks and the coastal space they use for breeding and migration, particularly for mother/calf pairs," Felix said. "We hope our density-distribution maps are carefully considered by the oil industry and governments planning seismic exploration in coastal areas along the North-South breeding axis of this species from Costa Rica to Peru," said Guzman. "Strong scientific evidence suggests that cetaceans behavior can be affected by this activity several kilometers from the exploration area." "By satellite tagging these animals we can better predict the impact of human activities on populations that are recovering by about 6 to 10 percent each year," Guzman said. "There are more whales to take care of now, and there's still a striking absence of policy governing the location of human activities, especially with increasing coastal maritime traffic overlapping migratory routes and oil exploration." In a second study off the coast of Chile, Guzman and Juan Capella from Whalesound followed a group of seven out of 25 whales tagged in the Magellan Strait to see if tagging affected their behavior or health during a period of several years. Tagging did not seem to affect whale behavior or their health or reproduction. Indeed, a female returned to the feeding area twice with new calves three and six years after tagging. Several individuals had small scars or lumps near the tag site, but they completely healed within two years. This study provides evidence to assist IACUC decisions by taking animal welfare into consideration. "We found the use of satellite-transmitter implants for remote tracking is harmless to the whale's health and breeding success, and doesn't damage the whales' bodies or alter their behavior but provides an enormous amount of data to inform managers," Capella said. "Using biotelemetry multiplied the information that we have about this group fivefold. We hope this will help decision makers understand the needs of this highly migratory species and leads to excellent, state-of-the-art management strategies for their survival," Guzman said. The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The institute furthers the understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. Website: http://www. . Guzman, H. M. y Félix, F. (2017) Movements and habitat use by Southeast Pacific Humpback Whales (Megaptera novaeangliae) satellite tracked at two breeding sites. Aquatic Mammals 2017, 43(2), 139-155, DOI 10.1578/AM.43.2.2017.139 Guzman, H. M. and Capella, J. J. (2017) Short-term recovery of humpback whales after percutaneous satellite tagging. The Journal of Wildlife Management, doi:10.1002/jwmg.21235


News Article | March 22, 2017
Site: www.techtimes.com

While already threatened by ocean warming or acidification, coral reefs around the world are facing another adversity in the form of dead zones. Hypoxia, or low oxygen levels, can create large dead zones that snuff out marine life and threaten dozens to hundreds of coral reefs worldwide, according to researchers from the Smithsonian Tropical Research Institute or STRI. Dead zones take place at the bottom of a body of water when there isn’t sufficient oxygen to sustain marine life. They form naturally but their number and severity have significantly increased in the recent decades, said lead study author Andrew Altieri. They are worsened by eutrophication, or a density of nutrients, as well as sewage inputs in coastal waters. This leads phytoplankton blooms and plankton to die, decompose, and draw off oxygen in the process. "The number of dead zones currently on our map of the world is 10 times higher in temperate areas than it is in the tropics, but many marine biologists work out of universities in Europe and North America and are more likely to find dead zones close to home," the STRI scientist said in a statement. Fortunately, while warming acidification demands large-scale solutions, dead zones are usually a localized issue and can be reduced through controlling sewage and agricultural runoff into the ocean, Altieri added. The study focused on the huge, semi-enclosed Almirante Bay, located around 174 square miles in the Bocas del Toro province in Panama. When they saw a massive coral reef die-off in the area in September 2010, the team suspected that a dead zone instead of warm or acidic ocean water could be the culprit. After measuring water quality and going through thick bacterial slime and dead marine animal bodies on the ocean floor, the researchers found extremely low oxygen levels in greater depths while there was still high oxygen in shallow waters where corals were healthy — a symptom of a dead zone. The findings, Altieri said, could apply to coral reefs globally, as dead zones may be commonly occurring in the tropics but have gone largely undocumented since scientists didn’t look for them. Another problem is that research institutions from tropical areas tend to suffer from poor funding compared with those in temperate regions. Dead zones may be underreported “by an order of magnitude,” warned co-author Nancy Knowlton, estimating that there are likely 10 for every 1 dead zone in the tropics. But the team saw that some coral species can fare better with low oxygen than others. Stephanocoenia intersepta, for instance, usually manages to survive in the Almirante Bay dead zone while others have died out. This species, though, is not a branching coral and does not offer an ideal habitat for others. Warming temperatures also play a role, since coastal environments become more vulnerable to hypoxia amid warming climate. Altieri insists on delving deeper into the tropics, proposing that at least 370 dead zones in the tropics remain undocumented. The findings were discussed in the journal PNAS. The Great Barrier Reef, while still recovering from the massive coral bleaching that ravaged 400 miles of its northern regions in 2016, is still facing an “elevated and imminent risk” of another widespread bleaching this year. Authorities are closely watching the accumulated heat stress it is demonstrating just like in the same period last year, when it experienced the worst bleaching incident. Experts have proposed different measures to mitigate bleaching, including addressing overfishing and pollution. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.


News Article | March 13, 2017
Site: www.techtimes.com

Beyond tourism concern, the trouble in Australia's Great Barrier Reef could spell trouble for mankind. It may seem far removed but the slow death the giant coral structure is experiencing could also foreshadow the doom that awaits the human society. This is even more alarming as the Great Barrier Reef is reported to have suffered from massive coral bleaching — the second of such event in two years. The question is not much in knowing what will happen to it and all other coral ecosystems in the world if the destruction goes on unabated but rather in knowing what will happen to society if it ever dies. All is not lost, however. Scientists agree that the Great Barrier Reef is in trouble and may be dying but it is not dead yet. It is not yet time to write the obituary. "This is a fatalistic, doomsday approach to climate change that isn't going to engage anyone and misinforms the public," coral reef expert Kim Cobb from Georgia Tech said. Cobb is convinced that a portion of the giant barrier reef and coral reefs around the world will stay beyond 2050. "I'm pretty confident of that. I'm put off by pieces that say we are doomed," he declared. These coral reefs are alive and they have the capacity to adapt to the changing climate. Researchers have discovered that some of the corals change their algal partners as they grow older. In this way, they can acquire algae that are more tolerant to heat brought about by global warming. There is hope, Terry Hughes, director of ARC Centre of Excellence for Coral Reef Studies, said. To save the coral ecosystem from demise is important to human survival. The 2014 report of the Food and Agriculture Organization underscored the importance of reefs as it provides some 17 percent of the protein global requirement. In some areas like Sierra Leone and Maldives, the figure may climb to as high as 70 percent. In addition, one-fourth of the marine species depend on coral reefs. There are several ways scientists believe they could do to save it and save humanity, too. A study conducted by the Smithsonian Tropical Research Institute in Panama found out that combination of warming and sea acidification is lethal to the health of corals. Based on this finding, one proposed conservation strategy is to add bicarbonates or lime to the water in order to reduce ocean acidity. It needs an estimated 10 cubic kilometers of lime every year to achieve this. To address warming, some scientists propose the building of giant shades on reefs in shallow waters. Replanting of corals with varieties that are heat-tolerant is also offered as one of the solutions. Toward this end, scientists are considering the idea of gardening coral reefs. These proposed strategies are limited when applied on a global scale. In the end, the reduction of carbon dioxide emissions is important to save the dying Great Barrier Reef and the whole coral ecosystem worldwide. "By 2050, we may still have corals, and things we call 'reefs', but they will be massive limestone structures that were built in the past, with tiny patches of living coral struggling to survive on them," coral ecologist Peter Sale said. He is convinced that the world without coral reefs will still survive but it will be less livable than we have now. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.


News Article | May 3, 2017
Site: www.eurekalert.org

VIDEO:  Extension of Continental, Marginal and Marine environments from ~18.4 to ~10.5 Ma showing the the two marine incursions reported in this study. view more A tiny shark tooth, part of a mantis shrimp and other microscopic marine organisms reveal that as the Andes rose, the Eastern Amazon sank twice, each time for less than a million years. Water from the Caribbean flooded the region from Venezuela to northwestern Brazil. These new findings by Smithsonian scientists and colleagues, published this week in Science Advances, fuel an ongoing controversy regarding the geologic history of the region. "Pollen records from oil wells in eastern Colombia and outcrops in northwestern Brazil clearly show two short-lived events in which ocean water from the Caribbean flooded what is now the northwest part of the Amazon basin," said Carlos Jaramillo, staff scientist at the Smithsonian Tropical Research Institute and lead author of the study. "Geologists disagree about the origins of the sediments in this area, but we provide clear evidence that they are of marine origin, and that the flooding events were fairly brief," Jaramillo said. His team dated the two flooding events to between 17 to18 million years ago and between 16 to 12 million years ago. Several controversial interpretations of the history of the region include the existence of a large, shallow sea covering the Amazon for millions of years, a freshwater megalake, shifting lowland rivers occasionally flooded by seawater, frequent seawater incusions, and a long-lived "para-marine metalake," which has no modern analog. Jaramillo assembled a diverse team from the Smithsonian and the University of Illinois at Urbana-Champaign; Corporacion Geologica Ares; the University of Birmingham; the University of Ghent; the Universidad del Norte, Baranquilla, Colombia; the University of Alberta, Edmonton; the University of Zurich; Ecopetrol, S.A.; Hocol, S.A.; the Royal Netherlands Institute for Sea Research at Utrecht University; the University of Texas of the Permian Basin; and the Naturalis Biodiversity Center. Together, they examined evidence including more than 50,000 individual pollen grains representing more than 900 pollen types from oil drilling cores from the Saltarin region of Colombia and found two distinct layers of marine pollen separated by layers of non-marine pollen types. They also found several fossils of marine organisms in the lower layer: a shark tooth and a mantis shrimp. "It's important to understand changes across the vast Amazonian landscape that had a profound effect, both on the evolution and distribution of life there and on the modern and ancient climates of the continent," Jaramillo said. The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a part of the Smithsonian Institution. The Institute furthers the understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. STRI website: http://www. . C. Jaramillo, I. Romero, C. D'Apolito, J. Ortiz. "Miocene flooding events of western Amazonia." Science Advances. Manuscript Number: sciadv.1601693; Smithsonian Tropical Research Institute


News Article | May 3, 2017
Site: www.sciencemag.org

The Amazon rainforest is a treasure trove of biodiversity, containing 10% of the planet’s species in its 6.7 million square kilometers. How it got to be that way has been fiercely disputed for decades. Now, a new study suggests that a large section of the forest was twice flooded by the Caribbean Sea more than 10 million years ago, creating a short-lived inland sea that jump-started the evolution of new species. But the new evidence still hasn’t convinced scientists on the other side of the debate. “It’s hard to imagine a process that would cover such a large forest with an ocean,” says lead author Carlos Jaramillo, a paleontologist at the Smithsonian Tropical Research Institute in Panama City who has been in both camps. Researchers generally agree that parts of the Amazon were once under water, but they don’t agree on where the water came from. Those in the “river camp” argue that freshwater streaming down from the rising Andes sliced up the land below, dividing plants and animals into isolated groups that later turned into new species. The fast-growing mountains also created microclimates at different elevations, sparking speciation and funneling new plants and animals into the Amazon basin. However, when marine microorganisms were discovered in Amazonian sediments in the 1990s, some scientists hypothesized that the forest was once inundated by an ocean, which created new species as forest dwellers quickly adapted to the flood. But proving either case—the river view or the ocean view—is tough. Rocks and fossils that could paint a definitive picture are exceedingly rare. So Jaramillo and his colleagues turned to a different kind of data: cores drilled into the jungle floor. Six centimeters wide and 600 meters deep, the cylindrical cores preserve a record of the region’s past environments in the form of pollen, fossils, and sediments, going back tens of millions of years. Jaramillo used two cores: one from eastern Colombia, drilled by an oil company, and one from northeastern Brazil, taken by the Brazilian Geology Survey in the 1980s. Jaramillo’s team went through the cores layer by layer. Most of the remains came from land-dwelling species. But in two thin layers, it found marine plankton and seashells. The Colombian core even contained a fossilized shark’s tooth and a mantis shrimp, both ocean dwellers. That was enough to convince Jaramillo, who was once firmly in the river camp, that the Caribbean Sea had reached down into the western Amazon of Brazil, Ecuador, and Peru twice: once 18 million years ago, and again 14 million years ago, he writes today in . “It’s a lost ecosystem,” he says. These seas didn’t last for long. In northwest Brazil, the first flood endured some 200,000 years, while the second lasted 400,000 years. Colombia, which is closer to the Caribbean, was inundated for a longer period, 900,000 and 3.7 million years, respectively. Those floods could have been caused by the growing Andes, Jaramillo says. The mountains would have pushed down the rest of the continent as they thrust upward, letting seawater flow in. But that water would have been quickly displaced as freshwater and sediments flowed down the peaks and rebuilt the basin. In geological time, these floods lasted a mere blink of the eye, Jaramillo says, “but it’s still a long time for a tree.” Even these relatively short events would have transformed the region. The new work “makes the case [for marine flooding] much stronger, and it makes the timing more definite,” says Carina Hoorn, a geologist and palynologist at the University of Amsterdam and Ikiam Regional University of Amazonia in Tena, Ecuador, who first proposed the marine flooding theory. But Paul Baker, a geologist at Duke University in Durham, North Carolina, and Yachay Tech in Urcuquí, Ecuador, is still a firm member of the river camp. “In [Colombia], I don’t have any problem with there being a marine incursion,” Baker says. But the Brazilian core troubles him, because marine-looking plankton has turned up in other ancient freshwater lakes in Europe, he says. More convincing to Baker would be a measurement of oxygen isotopes in the shells, which could reveal whether they grew in salt- or freshwater. Jaramillo says he’s already working on it. He’d also like to find more Amazonian fossils to study species that may have gone extinct during this dynamic time. For now, there’s only one thing Jaramillo, Hoorn, and Baker can all agree on: They will need to drill and study many more cores from across the region to solve the mystery of the Amazon’s biodiversity.


News Article | April 27, 2017
Site: www.eurekalert.org

The ability of some Western conifer forests to recover after severe fire may become increasingly limited as the climate continues to warm, scientists from the Smithsonian Conservation Biology Institute (SCBI) and Harvard Forest found in a new study published today in Global Change Biology. Although most of these cone-bearing evergreen trees are well adapted to fire, the study examines whether two likely facets of climate change -- hotter, drier conditions and larger, more frequent and severe wildfires -- could potentially transform landscapes from forested to shrub-dominated systems. As part of the study, which was funded by the National Science Foundation, scientists examined conifer forests in the richly diverse Klamath region of northern California and southwestern Oregon. The Klamath region is a botanical hotspot, home to 29 species of conifers and a suite of plant species that exist nowhere else on earth. The researchers sampled sites that burned severely in wildfires between 1987 and 2008. They found that, after fire, hardwood trees and shrubs quickly established by either re-sprouting from surviving root systems or growing rapidly from seeds that persisted in the soil. These plants dominated the vegetation for at least the first few decades after fire. Most conifers, on the other hand, were slow to compete, relying on establishment of new seedlings borne by trees in less severely burned patches or from outside the fire perimeter. As a result, conifers had only a few years to establish before the regenerating hardwoods and shrubs grew dense enough to suppress them. "If they miss that window there's much less chance of successful establishment and their growth will be slower," says study author Kristina Anderson-Teixeira, a forest ecologist at SCBI and the Smithsonian Tropical Research Institute. In fact, the study found that the longer the interval between the fire and the conifer's establishment, the slower the tree's growth. "The Klamath ecosystem is an important transition zone separating the shrubs of the California chaparral from the Pacific Northwest's temperate rainforest," says Jonathan Thompson, a Senior Ecologist at Harvard Forest and co-author on the study. "Our work suggests climate change will push the chaparral north at the expense of the Klamath's existing conifer forests." Because most conifers depend on seed dispersal from surviving trees, larger patches of high-severity fire could put a growing portion of the landscape at risk of poor post-fire conifer regeneration. The study suggests this trend could be even more pronounced because under drier conditions more abundant seed sources are needed to support conifer seedlings at densities sufficient for forest recovery. In addition, previous research by Thompson and others suggests the young, shrub-dominated vegetation that develops after severe fire tends to burn more severely in subsequent fires than older conifer forests, meaning that once severe fire converts a conifer forest to a shrub-dominated system, the non-forested vegetation could be perpetuated almost indefinitely through a cycle of repeated burning. "We see climate change affecting the system from two directions," says Thompson. "First, it is slowing conifer growth, keeping them low to the ground and more vulnerable to future fires for a longer period of time. Second, climate change is making fire more frequent. This phenomenon, which researchers call the 'interval squeeze,' threatens to transform this and other arid, fire-prone forests worldwide." Still, portions of the landscape may be relatively resilient. For example, conifers were able to regenerate in wetter sites, even amid relatively large high-severity patches with few surviving trees. "The Klamath region has supported conifers for thousands of years," says Thompson. "Some patches will surely survive no matter what climate throws at them." The researchers hope these findings could help provide information needed to prioritize management efforts. "Our study helps to identify the places that are at greatest risk of forest loss, where managers could either target management to promote post-fire forest recovery, or accept that we're going to see some degree of landscape transformation in the coming decades and learn to meet ecological objectives under the new climate and disturbance regimes," says Alan Tepley, a forest ecologist with SCBI and the study's lead author. These findings could also be applied in a broader context to other forest ecosystems. "There are concerns for much of the western U.S. and other similar landscapes that under climate change, forests may be less likely to regenerate," says Anderson-Teixeira. "And that can then reduce forest cover on the landscape and result in big losses of carbon storage." According to Anderson-Teixeira, the fate of the Klamath region depends in part on societal carbon emissions, where increased emissions lead to more warming, which ultimately could result in more forest loss. An additional author on this paper is Howard Epstein from the University of Virginia. The study is part of a large collaborative effort that includes the US Forest Service and Portland State University. The Harvard Forest, founded in 1907 and located in Petersham, Mass., is Harvard University's outdoor laboratory and classroom for ecology and conservation, and a Long-Term Ecological Research (LTER) site funded by the National Science Foundation. Its 4,000 acre property is one of the oldest and most intensively studied research forests in the U.S. In addition to studying New England landscapes, research scientists at the Forest study ecosystems around the U.S. and the globe. More information can be found at http://harvardforest. . SCBI plays a leading role in the Smithsonian's global efforts to save species from extinction and train future generations of conservationists. SCBI spearheads research programs at its headquarters in Front Royal, Va., the Smithsonian's National Zoo in Washington, D.C., and at field research stations and training sites worldwide. SCBI scientists tackle some of today's most complex conservation challenges by applying and sharing what they learn about animal behavior and reproduction, ecology, genetics, migration and conservation sustainability. For interviews with a Harvard Forest scientist or contacts for SCBI scientists, contact Clarisse Hart, hart3@fas.harvard.edu; 978-756-6157.


Riehl C.,Smithsonian Tropical Research Institute
Proceedings. Biological sciences / The Royal Society | Year: 2013

Cooperatively breeding animals live in social groups in which some individuals help to raise the offspring of others, often at the expense of their own reproduction. Kin selection--when individuals increase their inclusive fitness by aiding genetic relatives--is a powerful explanation for the evolution of cooperative breeding, particularly because most groups consist of family members. However, recent molecular studies have revealed that many cooperative groups also contain unrelated immigrants, and the processes responsible for the formation and maintenance of non-kin coalitions are receiving increasing attention. Here, I provide the first systematic review of group structure for all 213 species of cooperatively breeding birds for which data are available. Although the majority of species (55%) nest in nuclear family groups, cooperative breeding by unrelated individuals is more common than previously recognized: 30% nest in mixed groups of relatives and non-relatives, and 15% nest primarily with non-relatives. Obligate cooperative breeders are far more likely to breed with non-kin than are facultative cooperators, indicating that when constraints on independent breeding are sufficiently severe, the direct benefits of group membership can substitute for potential kin-selected benefits. I review three patterns of dispersal that give rise to social groups with low genetic relatedness, and I discuss the selective pressures that favour the formation of such groups. Although kin selection has undoubtedly been crucial to the origin of most avian social systems, direct benefits have subsequently come to play a predominant role in some societies, allowing cooperation to persist despite low genetic relatedness.


Wright S.J.,Smithsonian Tropical Research Institute
Annals of the New York Academy of Sciences | Year: 2010

Five anthropogenic drivers-land use change, wood extraction, hunting, atmospheric change, climate change-will largely determine the future of tropical forests. The geographic scope and intensity of these five drivers are in flux. Contemporary land use change includes deforestation (∼64,000 km2 yr-1 for the entire tropical forest biome) and natural forests regenerating on abandoned land (∼21,500 km2 yr-1 with just 29% of the biome evaluated). Commercial logging is shifting rapidly from Southeast Asia to Africa and South America, but local fuelwood consumption continues to constitute 71% of all wood production. Pantropical rates of net deforestation are declining even as secondary and logged forests increasingly replace old-growth forests. Hunters reduce frugivore, granivore and browser abundances in most forests. This alters seed dispersal, seed and seedling survival, and hence the species composition and spatial template of plant regeneration. Tropical governments have responded to these local threats by protecting 7% of all land for the strict conservation of nature - a commitment that is only matched poleward of 40°S and 70°N. Protected status often fails to stop hunters and is impotent against atmospheric and climate change. There are increasing reports of stark changes in the structure and dynamics of protected tropical forests. Four broad classes of mechanisms might contribute to these changes. Predictions are developed to distinguish among these mechanisms. © 2010 New York Academy of Sciences.


Leigh Jr. E.G.,Smithsonian Tropical Research Institute
Journal of Evolutionary Biology | Year: 2010

Many thought Darwinian natural selection could not explain altruism. This error led Wynne-Edwards to explain sustainable exploitation in animals by selection against overexploiting groups. Williams riposted that selection among groups rarely overrides within-group selection. Hamilton showed that altruism can evolve through kin selection. How strongly does group selection influence evolution? Following Price, Hamilton showed how levels of selection interact: group selection prevails if Hamilton's rule applies. Several showed that group selection drove some major evolutionary transitions. Following Hamilton's lead, Queller extended Hamilton's rule, replacing genealogical relatedness by the regression on an actor's genotypic altruism of interacting neighbours' phenotypic altruism. Price's theorem shows the generality of Hamilton's rule. All instances of group selection can be viewed as increasing inclusive fitness of autosomal genomes. Nonetheless, to grasp fully how cooperation and altruism evolve, most biologists need more concrete concepts like kin selection, group selection and selection among individuals for their common good. © 2009 European Society for Evolutionary Biology.


Leigh E.G.,Smithsonian Tropical Research Institute
Journal of Evolutionary Biology | Year: 2010

Like altruism, mutualism, cooperation between species, evolves only by enhancing all participants' inclusive fitness. Mutualism evolves most readily between members of different kingdoms, which pool complementary abilities for mutual benefit: some of these mutualisms represent major evolutionary innovations. Mutualism cannot persist if cheating annihilates its benefits. In long-term mutualisms, symbioses, at least one party associates with the other nearly all its life. Usually, a larger host harbours smaller symbionts. Cheating is restrained by vertical transmission, as in Buchnera; partner fidelity, as among bull-thorn acacias and protective ants; test-based choice of symbionts, as bobtail squid choose bioluminescent bacteria; or sanctioning nonperforming symbionts, as legumes punish nonperforming nitrogen-fixing bacteria. Mutualisms involving brief exchanges, as among plants and seed-dispersers, however, persist despite abundant cheating. Both symbioses and brief-exchange mutualisms have transformed whole ecosystems. These mutualisms may be steps towards ecosystems which, like Adam Smith's ideal economy, serve their members' common good. No claim to original US government works. Journal compilation © 2010 European Society for Evolutionary Biology.

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