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Habitat destruction and degradation are the leading causes of species declines and extinctions in the world. Human altered landscapes often leave fragments of previously continuous habitat, which may be of significant conservation value. We assessed the effects of habitat fragmentation on the taxonomic diversity, community composition, and nestedness of avian communities before and after fragment isolation at the Biological Dynamics of Forest Fragments Project research site in the Amazon rainforest. Species loss in 10ha and 100ha fragments was significantly different from random taxonomic loss. In addition, after fragment isolation, but not prior to fragmentation, the species in the 10ha fragments were a nested subset of the species in the 100ha fragments. Finally, within the fragments two distinct communities formed, those on the edge of the fragments and those at the interior of the fragments, indicating that edge species did not penetrate the interior portion of the fragments. The controlled isolation of fragments from continuous forest resulted in rapid changes in the taxonomic diversity and species composition where fragment size served as a driver of species assemblages across the landscape. We suggest that future research continue to assess community level adjustments to habitat fragmentation and investigate the drivers behind the non-random loss of taxonomic groups and the nested structure of species composition of smaller fragments into larger ones after habitat fragmentation.

The efforts to increase protected area coverage are overlooking the importance of remaining wilderness areas.

Thomas E. Lovejoy Lee Hannah Although models of climate and vegetation change are greatly improving, they remain far from perfect. For example, on the one hand, recent modeling studies indicate that limiting temperature increase to 1.5°C will greatly reduce the impact on the ranges of insect, vertebrate, and plant communities. However, we also know that, since these models do not account for critical climate-sensitive relationships among species, their predictions are serious underestimates. New research is allowing scientists to better understand the fine-tunings of climate-sensitive relationships among species, including how even very small changes of temperature can have devastating effects on ecosystems. We know, for example, that many coral bleaching events are due to temperature-based disruption of coral reef ecosystems. Even a subtle increase of temperature for a short period can cause coral animals to eject their symbiotic algae, a separation that quickly leads to coral bleaching and often to mortality and the collapse of the entire reef ecosystem. Another example of huge impacts resulting from small temperature changes is that slightly …

Not all that protected, after all The intention of creating protected natural areas is to protect them in the long term from destructive human activities. Governments do not always follow these intentions, however, and often legally remove protections and reduce the extent of protected areas. Golden Kroner et al. looked across the United States and Amazonia over the past 200 years and found more than 700 such changes, two-thirds of which have occurred since the year 2000 (see the Perspective by Naughton-Treves and Holland). The majority of these were to permit destructive practices, such as resource extraction. Thus, these changes do not just alter status but lead to irreparable environmental harm. Science , this issue p. 881 ; see also p. 832

Thomas E. Lovejoy Carlos Nobre In the 1970s, Brazilian scientist Eneas Salati shattered the long held dogma that vegetation is simply the consequence of climate and has no influence on climate whatsoever ( 1 ). Using isotopic ratios of oxygen in rainwater samples collected from the Atlantic to the Peruvian border, he was able to demonstrate unequivocally that the Amazon generates approximately half of its own rainfall by recycling moisture 5 to 6 times as airmasses move from the Atlantic across the basin to the west. From the start, the demonstration of the hydrological cycle of the Amazon raised the question of how much deforestation would be required to cause the cycle to degrade to the point of being unable to support rain forest ecosystems. High levels of evaporation and transpiration that forests produce throughout the year contribute to a wetter atmospheric boundary layer than would be the case with …

In addition to the physical impacts of climate change—the retreat of ice in most places, change in fire regimes, extreme weather events (droughts, major storms), sea level rise and ocean acidification, there are multiple biological impacts. The latter are no longer just modest changes in phenology and geographical distribution. The shift to accelerating change makes a strong case for limiting climate change to no more than 1.5° above pre-industrial temperature. That challenging goal can only be achieved by lowering greenhouse gas concentrations. Restoration of extensive historically degraded and destroyed ecosystems has the potential to substantially lower atmospheric CO2 concentrations—hence a “wild solution” to climate change.

Climate change and its interactions with human modification of the biosphere will result in major changes in species and ecosystem distributions, dynamics, and interactions. Here, we discuss major categories of management responses to climate change impacts on biodiversity. Adaptation or adjustment of natural or human systems are explored, including common conservation strategies, protected areas, and landscape and seascape connectivity. Ecosystem-based adaptation is defined and explored, to highlight the benefits of conserving ecosystems for the inherent services they provide to humans. Reduced Emissions from Deforestation and Degradation (REDD +) policy have great potential to reduce greenhouse gas emissions from clearing of forests in subtropical and tropical countries. Implementation and financing this policy has been a challenge with many recommendations for improvement and successful implementation and is a topic that is being refined in international dialoges. The detrimental impacts of deforestation through land use changes for biofuel production are very significant, and biofuels have a long payback period and release between 17 and 420 times more emissions upfront. Conservation needs to be concerned with both the direct impacts of climate change on biodiversity, but also the indirect effects (positive) of REDD and the negative indirect effects of biofuels production.

Funding Information: Natural Environment Research Council (NERC), Grant/Award Number: NE/ N004655/1; NERC Consortium Grants “AMAZONICA”; BIO‐RED; European Research Council (ERC); The Gordon and Betty Moore Foundation; European Union's Seventh Framework Programme, Grant/ Award Number: 282664; Royal Society, Grant/Award Number: CH160091; Royal Society Wolfson Research Merit Award. Most of the planet's diversity is concentrated in the tropics, which includes many regions undergoing rapid climate change. Yet, while climate-induced biodiversity changes are widely documented elsewhere, few studies have addressed this issue for lowland tropical ecosystems. Here we investigate whether the floristic and functional composition of intact lowland Amazonian forests have been changing by evaluating records from 106 long-term inventory plots spanning 30 years. We analyse three traits that have been hypothesized to respond to different environmental drivers (increase in moisture stress and atmospheric CO2 concentrations): maximum tree size, biogeographic water-deficit affiliation and wood density. Tree communities have become increasingly dominated by large-statured taxa, but to date there has been no detectable change in mean wood density or water deficit affiliation at the community level, despite most forest plots having experienced an intensification of the dry season. However, among newly recruited trees, dry-affiliated genera have become more abundant, while the mortality of wet-affiliated genera has increased in those plots where the dry season has intensified most. Thus, a slow shift to a more dry-affiliated Amazonia is underway, with changes in compositional dynamics (recruits and mortality) consistent with climate-change drivers, but yet to significantly impact whole-community composition. The Amazon observational record suggests that the increase in atmospheric CO2 is driving a shift within tree communities to large-statured species and that climate changes to date will impact forest composition, but long generation times of tropical trees mean that biodiversity change is lagging behind climate change. Publisher PDF

This is an editorial for the special series.

Many contemporary ecosystems are likely to be affected by multiple environmental drivers, complicating efforts to predict future changes in those ecosystems. We studied long-term changes (1980–2012) in forest dynamics and liana (woody vine) abundance and biomass in fragmented and intact forests of the central Amazon. We did so by contrasting trends in 33 permanent 1-ha plots near forest edges (plot center

The US National Park System is significantly different – in scope, number of units, size and complexity – than in the 1960s when the Leopold Report. Scientific understanding of natural and cultural resources has expanded dramatically. Developments since the 1960s include increasing biodiversity loss, habitat fragmentation, land use change, groundwater depletion, invasive species, rapid and sometimes unplanned development, growing air, noise, and light pollution and the impacts of climate change. The cultural values and interests held by the American people have also broadened, generating pressing demands for parks to reflect diversity and relevance for new generations. Fifty years on, the National Parks Service and its National Park System Advisory Board have revisited the Leopold Report. The new report, Revisiting Leopold, published here, focuses on the natural and cultural resource management of the National Park System and answers three questions: 1) What should be the goals of resource management in the National Park System?; 2) What policies for resource management are necessary to achieve these goals?; 3) What actions are required to implement these policies?

The population extinction pulse we describe here shows, from a quantitative viewpoint, that Earth's sixth mass extinction is more severe than perceived when looking exclusively at species extinctions. Therefore, humanity needs to address anthropogenic population extirpation and decimation immediately. That conclusion is based on analyses of the numbers and degrees of range contraction (indicative of population shrinkage and/or population extinctions according to the International Union for Conservation of Nature) using a sample of 27,600 vertebrate species, and on a more detailed analysis documenting the population extinctions between 1900 and 2015 in 177 mammal species. We find that the rate of population loss in terrestrial vertebrates is extremely high-even in "species of low concern." In our sample, comprising nearly half of known vertebrate species, 32% (8,851/27,600) are decreasing; that is, they have decreased in population size and range. In the 177 mammals for which we have detailed data, all have lost 30% or more of their geographic ranges and more than 40% of the species have experienced severe population declines (80% range shrinkage). Our data indicate that beyond global species extinctions Earth is experiencing a huge episode of population declines and extirpations, which will have negative cascading consequences on ecosystem functioning and services vital to sustaining civilization. We describe this as a "biological annihilation" to highlight the current magnitude of Earth's ongoing sixth major extinction event.

Made available in DSpace on 2018-12-11T16:48:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-09-01 National Research Council of Science and Technology Amazon forests are fire-sensitive ecosystems and consequently fires affect forest structure and composition. For instance, the legacy of past fire regimes may persist through some species and traits that are found due to past fires. In this study, we tested for relationships between functional traits that are classically presented as the main components of plant ecological strategies and environmental filters related to climate and historical fires among permanent mature forest plots across the range of local and regional environmental gradients that occur in Amazonia. We used percentage surface soil pyrogenic carbon (PyC), a recalcitrant form of carbon that can persist for millennia in soils, as a novel indicator of historical fire in old-growth forests. Five out of the nine functional traits evaluated across all 378 species were correlated with some environmental variables. Although there is more PyC in Amazonian soils than previously reported, the percentage soil PyC indicated no detectable legacy effect of past fires on contemporary functional composition. More species with dry diaspores were found in drier and hotter environments. We also found higher wood density in trees from higher temperature sites. If Amazon forest past burnings were local and without distinguishable attributes of a widespread fire regime, then impacts on biodiversity would have been small and heterogeneous. Alternatively, sufficient time may have passed since the last fire to allow for species replacement. Regardless, as we failed to detect any impact of past fire on present forest functional composition, if our plots are representative then it suggests that mature Amazon forests lack a compositional legacy of past fire. Laboratório de Ecologia Vegetal Universidade do Estado de Mato Grosso (UNEMAT) Instituto de Ciência e Tecnologia Universidade Estadual Paulista (Unesp) College of Science and Engineering and Centre for Tropical Environmental and Sustainability Science (TESS) James Cook University School of Geography University of Leeds Biological Dynamics of Forest Fragments Project National Institute for Amazonian Research (INPA) and Smithsonian Tropical Research Institute Laboratoire EDB Université Paul Sabatier Instituto de Investigaciones de la Amazonía Peruana Coordenação de Botânica Museu Paraense Emilio Goeldi National Institute for Amazonian Research (INPA) Department of Environmental Science and Policy George Mason University Environmental Change Institute School of Geography and the Environment University of Oxford Proyecto Flora del Peru Jardin Botanico de Missouri Puyo Universidad Estatal Amazónica Instituto de Ciencias Naturales Universidad Nacional de Colombia Universidad de Los Andes Naturalis Biodiversity Center Systems Ecology Free University, De Boelelaan 1087 University of Washington Geography College of Life and Environmental Sciences University of Exeter Instituto de Ciência e Tecnologia Universidade Estadual Paulista (Unesp) National Research Council of Science and Technology: PELD 403725/2012-7 National Research Council of Science and Technology: PPBio 457602/2012-0 National Research Council of Science and Technology: PVE 401279/2014-6

Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-Tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable within 1 ha plots, indicating that diversity effects in tropical forests may be scale dependent. The absence of clear diversity-carbon relationships at scales relevant to conservation planning means that carbon-centred conservation strategies will inevitably miss many high diversity ecosystems. As tropical forests can have any combination of tree diversity and carbon stocks both require explicit consideration when optimising policies to manage tropical carbon and biodiversity., 0, SCOPUS: ar.j, info:eu-repo/semantics/published

One of the fundamental challenges of climate change is that we contribute to it increment by increment, and experience it increment by increment after a considerable time lag. As a consequence, it is very difficult to see what we are doing to ourselves, to future generations, and to the living planet as a whole. There are monumental ethical issues involved, but they are obscured by the incremental nature of the process and the long time frame before reaching the concentration of greenhouse gases and the ensuing accumulation of radiant heat—and consequent climate change—that ensues.

We propose the wildlife premium mechanism as an innovation to conserve endangered large vertebrates. The performance-based payment scheme would allow stakeholders in lower-income countries to generate revenue by recovering and maintaining threatened fauna that can also serve as umbrella species (i.e., species whose protection benefits other species with which they co-occur). There are 3 possible options for applying the premium: option 1, embed premiums in a carbon payment; option 2, link premiums to a related carbon payment, but as independent and legally separate transactions; option 3, link premiums to noncarbon payments for conserving ecosystem services (PES). Each option presents advantages, such as incentive payments to improve livelihoods of rural poor who reside in or near areas harboring umbrella species, and challenges, such as the establishment of a subnational carbon credit scheme. In Kenya, Peru, and Nepal pilot premium projects are now underway or being finalized that largely follow option 1. The Kasigau (Kenya) project is the first voluntary carbon credit project to win approval from the 2 leading groups sanctioning such protocols and has already sold carbon credits totaling over $1.2 million since June 2011. A portion of the earnings is divided among community landowners and projects that support community members and has added over 350 jobs to the local economy. All 3 projects involve extensive community management because they occur on lands where locals hold the title or have a long-term lease from the government. The monitoring, reporting, and verification required to make premium payments credible to investors include transparent methods for collecting data on key indices by trained community members and verification of their reporting by a biologist. A wildlife premium readiness fund would enable expansion of pilot programs needed to test options beyond those presented here.

A great challenge for ecologists is predicting how communities in fragmented tropical landscapes will change in the future. Available evidence suggests that fragmented tropical tree communities are progressing along a trajectory of ‘retrogressive succession’, in which the community shifts towards an early or mid-successional state that will persist indefinitely. Here, we investigate the potential endpoint of retrogressive succession, examining whether it will eventually lead to the highly depauperate communities that characterise recently abandoned agricultural lands. We tested this hypothesis by using neural networks to construct an empirical model of Amazonian rainforest-tree-community responses to experimental habitat fragmentation. The strongest predictor of tree-community composition in the future was its composition in the present, modified by variables like the composition of the surrounding habitat matrix and distance to forest edge. We extrapolated network predictions over a 100 year period and quantified trajectories of forest communities in multidimensional ordination space. We found no evidence that forest communities, including those near forest edges, were converging strongly towards a composition dominated by just one or two early successional genera. Retrogressive succession may well be stronger in fragmented landscapes altered by chronic disturbances, such as edge-related fires, selective logging, or intense windstorms, but in this experimental landscape in which other human disturbances are very limited, it is unlikely that forest edge communities will fully revert to the species poor assemblages observed in very early successional landscapes. This article is protected by copyright. All rights reserved.

In her News In Depth story “Brazilian crisis threatens science and environment” (27 May, p. [1044][1]), L. Wade explored the consequences of the controversial constitutional amendment that is under consideration in the Brazilian Senate amidst the country's economic and political turmoil. This

Introduction In June 2012, corporate, nongovernmental (NGO), and government leaders will converge in Rio de Janeiro, Brazil for a conference on sustainable development. Occurring twenty years after the first Rio conference, the "Earth Summit," the 2012 meeting is a chance to examine and reaffirm commitments to global sustainability.As articulated by the United Nations Industrial Development Organization (UNIDO), the meeting provides a timely opportunity to ensure a "shared and common understanding of [sustainability] and what it means to improve the lives of ordinary people in developing countries and countries with economies in transition" (UNIDO, 2011). The title of the initial draft of the conference outcome document, "The Future We Want," is the inspiration for the title of thisarticle (UNCSD, 2011).Over the next two decades, governments and businesses will face serious environmental and social changes that hold both risks and opportunities (KPMG, 2012). We are optimistic that we have the capacity to meet these challenges and achieve a strong global economy while advancing social well-being and protecting human health and the environment.Several trends inspire our hopefulness: leaders in corporations and financial institutions are moving toward sustainable operations and globally responsible investing; advances in science, technology, innovation, and social marketing via the Internet are creating new economic opportunities for sustainability; and national, state, and local governments around the world are taking leadership roles in pursuing sustainability.Some commentators are less optimistic about the future. As The Economist (2011) observed in a recent review of the planet's growing population and its potential impacts, "Once upon a time, the passing of population milestones might have been a cause of celebration. Now it gives rise to jeremiads" (emphasis in original). Population growth, along with increasing affluence in developing nations, is seen as a primary driver of the growing, unsustainable global demand for energy and natural resources.The future is indeed fraught with environmental, economic, and social risks that could derail progress. For example, the ecological footprint measure assembled by the Global Footprint Network (2011) notes that humanity's ecological footprint has more than doubled since 1966. The Network'scalculations indicate that if every human today were consuming resources at a level typical of developed countries, we would need three or four planets with natural resources equivalent to Earth.The challenge ahead is to meet the needs of the growing population in a way that restores and maintains the Earth's natural resources while promoting economic prosperity. This is what "sustainable development" is all about. Sustainability has in turn been widely characterized as resting on three pillars: social well-being, economic prosperity, and environmental protection.From the perspective of public policy, sustainability is aimed at meeting society's basic economic and social needs without undermining the natural resource base and environmental quality necessary for continuing to meet those needs in the future. From the standpoint of business and finance, sustainability is evolving into a platform for innovation and value creation at a global market scale for shareholders and society while efficiently using resources and minimizing adverse effects on the environment. The traditional tension between corporate environmental responsibility and profitability is giving way to a convergence between public and private sector interests, as illustrated by numerous examples cited in this article.Today, government, business, and civil society are developing a shared view of sustainability as a force for spurring innovation, strengthening competitiveness, and enhancing quality of life through transformed leadership of our major institutions. But fundamental changes in institutional approaches are necessary to make this happen. …

Insufficient focused attention has been paid by the conservation community to conservation of biodiversity outside of protected areas. Biodiversity mainstreaming addresses this gap in global conservation practice by “embedding biodiversity considerations into policies, strategies and practices of key public and private actors that impact or rely on biodiversity, so that it is conserved, and sustainably used, both locally and globally” (Huntley and Redford, 2014). Biodiversity mainstreaming is designed to change those policies and practices that influence land uses outside of protected areas as well as to change economic and development decision-making by demonstrating the importance of conserving biodiversity for achieving development outcomes. The practice of mainstreaming is tied to implementation of the Convention on Biological Diversity and is practiced with billions of dollars of investment by development agencies, national government agencies, and the Global Environment Facility (GEF) and its implementing organizations as well as other donors. It is essential for the long-term survival of biodiversity inside and outside protected areas. However, it is virtually unheard of in the main conservation science field. This must change so as to bring careful documentation, analysis, monitoring, publishing, and improvement of practices—all things that conservation science should provide as partners to practitioners of biodiversity mainstreaming. The situation is ripe for informed coordination and consolidation and creation of a science-driven field of biodiversity mainstreaming.

George Evelyn Hutchinson, born on 13 January 1903 in Cambridge, is considered by many to be the father of modern ecology because he infused the science with theory that was anchored in natural history. When called the father of ecology in 1973 on receiving the very first Tyler Prize, he instantly demurred, saying that credit should go to Darwin and Charles Elton, and further that what he was really proud of was the string of wonderfully bright students who had studied with him. Nonetheless in many senses and to a major extent Hutchinson can be credited with transforming natural history into a science. He spent most of his professional years at Yale and returned to England in 1991 for the last months of his life.

We synthesize findings to date from the world’s largest and longest-running experimental study of habitat fragmentation, located in central Amazonia. Over the past 32 years, Amazonian forest fragments ranging from 1 to 100 ha have experienced a wide array of ecological changes. Edge effects have been a dominant driver of fragment dynamics, strongly affecting forest microclimate, tree mortality, carbon storage, fauna, and other aspects of fragment ecology. However, edge-effect intensity varies markedly in space and time, and is influenced by factors such as edge age, the number of nearby edges, and the adjoining matrix of modified vegetation surrounding fragments. In our study area, the matrix has changed markedly over the course of the study (evolving from large cattle pastures to mosaics of abandoned pasture and regrowth forest) and this in turn has strongly influenced fragment dynamics and faunal persistence. Rare weather events, especially windstorms and droughts, have further altered fragment ecology. In general, populations and communities of species in fragments are hyperdynamic relative to nearby intact forest. Some edge and fragment-isolation effects have declined with a partial recovery of secondary forests around fragments, but other changes, such as altered patterns of tree recruitment, are ongoing. Fragments are highly sensitive to external vicissitudes, and even small changes in local land-management practices may drive fragmented ecosystems in markedly different directions. The effects of fragmentation are likely to interact synergistically with other anthropogenic threats such as logging, hunting, and especially fire, creating an even greater peril for the Amazonian biota.

The article examines an underexplored episode of the Brazilian history in the context of the Cold War: the role of the Hudson Institute in South America and the proposal to create a large lacustrine system in the Amazon domains. From the analysis of official documents and literary registers, some of them little-known from the public, we attempted to identify the existence of a relationship between the aforementioned project and the Cold War systemic agenda and, also, the role of Brazil in this paradigmatic moment of the contemporary history. Evidences did not allow us to point out a clear connection between the Amazon Great Lakes Project and the dynamics of the United States-Soviet Union political disputes, even though they have shown that such an enterprise, if carried out, could make the Hylea a low-cost arena for the achievement of U.S. interests in the Cold War's game of power.

Summary There is already widespread change in the natural calendars (phenology) of plants and animals, as well as change in some species distributions. Now threshold change (sudden, fundamental change) in ecosystems is beginning to be observed in nature. At minimum, the natural world will experience an equal amount of warming to that which has already taken place. This all suggests a future with nature and ecosystems very much in flux with profound implications for epidemiology.

Fragmentation can alter the ecology of rain forest remnants in many ways, but its long-term effects on tree communities are poorly understood. One phenomenon that has received little attention is tree regeneration in fragmented forests (Janzen 1983; Viana et al. 1997). Patterns of regeneration are important because they will ultimately determine the floristic composition of the remnant. Janzen (1983) suggested that fragments of tropical dry forest in Costa Rica are prone to invasions of weedy, generalist plant species from the surrounding modified matrix, which could progressively alter the floristic composition of remnants. Laurance (1991, 1997) proposed that fragments in some tropical regions are chronically disturbed by winds and other factors and may exhibit a general shift toward successional trees, lianas, and vines adapted for recurring disturbance. Using data collected over 13 years, we describe patterns of tree recruitment in a fragmented landscape in central Amazonia. We ask three questions: (1) Do rates of tree recruitment differ between fragmented and continuous forests? (2) Are recruitment rates influenced by fragment area, age, and proximity of forest edge? (3) Are regenerating trees in fragments biased toward successional species or against old-growth species?

Many ecologists believe birds disappear from tropical forest fragments because they are poor dispersers. We test this idea using a spatially explicit capture data base from the Biological Dynamics of Forest Fragments Project near Manaus, Brazil. We measure bird movements directly, over relatively large scales of space and time, both before and after landscape fragmentation. We found that species which disappear from fragments move extensively between plots before isolation, but not after, and often disperse to longer distances in continuous forest than in fragmented forest. Such species also preferentially emigrate from smaller to larger fragments, showing no preference in continuous forest. In contrast, species that persist in fragments are generally less mobile, do not cross gaps as often, yet disperse further after fragmentation than before. " Heavy tailed" probability models usually explain dispersal kernels better than exponential or Gaussian models, suggesting tropical forest birds may be better dispersers than assumed with some individuals moving very long distances. Ecol Lett

Urgent need for conservation and restoration measures to improve landscape connectivity., We conducted an analysis of global forest cover to reveal that 70% of remaining forest is within 1 km of the forest’s edge, subject to the degrading effects of fragmentation. A synthesis of fragmentation experiments spanning multiple biomes and scales, five continents, and 35 years demonstrates that habitat fragmentation reduces biodiversity by 13 to 75% and impairs key ecosystem functions by decreasing biomass and altering nutrient cycles. Effects are greatest in the smallest and most isolated fragments, and they magnify with the passage of time. These findings indicate an urgent need for conservation and restoration measures to improve landscape connectivity, which will reduce extinction rates and help maintain ecosystem services.

Forest fragmentation is considered a greater threat to vertebrates than to tree communities because individual trees are typically long-lived and require only small areas for survival. Here we show that forest fragmentation provokes surprisingly rapid and profound alterations in Amazonian tree-community composition. Results were derived from a 22-year study of exceptionally diverse tree communities in 40 1-ha plots in fragmented and intact forests, which were sampled repeatedly before and after fragment isolation. Within these plots, trajectories of change in abundance were assessed for 267 genera and 1,162 tree species. Abrupt shifts in floristic composition were driven by sharply accelerated tree mortality and recruitment within ≈ 100 m of fragment margins, causing rapid species turnover and population declines or local extinctions of many large-seeded, slow-growing, and old-growth taxa; a striking increase in a smaller set of disturbance-adapted and abiotically dispersed species; and significant shifts in tree size distributions. Even among old-growth trees, species composition in fragments is being restructured substantially, with subcanopy species that rely on animal seed-dispersers and have obligate outbreeding being the most strongly disadvantaged. These diverse changes in tree communities are likely to have wide-ranging impacts on forest architecture, canopy-gap dynamics, plant-animal interactions, and forest carbon storage. © 2006 by The National Academy of Sciences of the USA.

The rainforests of the Amazon basin are being cut by humans at a rate >20,000 km 2 /year, leading to smaller and more isolated patches of forest, with remaining fragments often in the range of 1-100 ha. We analyzed samples of understory birds collected over 20 years from a standardized mist-netting program in 1- to 100-ha rainforest fragments in a dynamic Amazonian landscape near Manaus, Brazil. Across bird guilds, the condition of second growth immediately surrounding fragments was often as important as fragment size or local forest cover in explaining variation in abundance. Some fragments surrounded by 100 m of open pasture showed reductions in insectivorous bird abundance of over 95%, even in landscapes dominated by continuous forest and old second growth. These extreme reductions may be typical throughout Amazonia in small (≤10 ha), isolated fragments of rainforest. Abundance for some guilds returned to preisolation levels in 10- and 100-ha fragments connected to continuous forest by 20-year-old second growth. Our results show that the consequences of Amazonian forest loss cannot be accurately described without explicit consideration of vegetation dynamics in matrix habitat. Any dichotomous classification of the landscape into "forest" and "nonforest" misses essential information about the matrix.

In the face of worldwide habitat fragmentation, managers need to devise a time frame for action. We ask how fast do understory bird species disappear from experimentally isolated plots in the Biological Dynamics of Forest Fragments Project, central Amazon, Brazil. Our data consist of mist-net records obtained over a period of 13 years in 11 sites of 1, 10, and 100 hectares. The numbers of captures per species per unit time, analyzed under different simplifying assumptions, reveal a set of species-loss curves. From those declining numbers, we derive a scaling rule for the time it takes to lose half the species in a fragment as a function of its area. A 10-fold decrease in the rate of species loss requires a 1,000-fold increase in area. Fragments of 100 hectares lose one half of their species in

We synthesized key findings from the Biological Dynamics of Forest Fragments Project, the world's largest and longest-running experimental study of habitat fragmentation. Although initially designed to assess the influence of fragment area on Amazonian biotas, the project has yielded insights that go far beyond the orig- inal scope of the study. Results suggest that edge effects play a key role in fragment dynamics, that the matrix has a major influence on fragment connectivity and functioning, and that many Amazonian species avoid even small ( � 100-m-wide) clearings. The effects of fragmentation are highly eclectic, altering species richness and abundances, species invasions, forest dynamics, the trophic structure of communities, and a variety of ecological and ecosystem processes. Moreover, forest fragmentation appears to interact synergistically with ecological changes such as hunting, fires, and logging, collectively posing an even greater threat to the rainforest biota. Descomposicion del Ecosistema en Fragmentos de Bosque Amazonico, Una Investigacion de 22 Anos Resumen: Sintetizamos resultados clave del proyecto sobre Dinamicas Biologicas de Fragmentos de bosque, el estudio experimental sobre fragmentacion del habitat mas largo y de mayor trayectoria del mundo. A pesar de que inicialmente el proyecto se diseno para evaluar la influencia del area de fragmentos en biotas del Amazo- nas, ha proporcionado un entendimiento que va mas alla del proposito original del estudio. Los resultados sugieren que los efectos de borde juegan un papel clave en las dinamicas de los fragmentos, que la matriz tiene una influencia mayor sobre la conectividad y el funcionamiento del fragmento y que muchas de las especies del Amazonas evitan areas taladas pequenas (de hasta � 100 m de ancho). Los efectos de la fragmentacion son al- tamente eclecticos, alterando la riqueza y abundancia de especies, las invasiones de especies, las dinamicas del bosque, la estructura trofica comunitaria y una variedad de procesos ecologicos y del ecosistema. Mas aun, la fragmentacion del bosque aparentemente interactua sinergisticamente con cambios ecologicos como lo son la caza, los incendios y la tala, representando colectivamente una gran amenaza sobre la biota del bosque lluvioso.

Lianas (climbing woody vines) are important structural parasites of tropical trees and may be increasing in abundance in response to global-change drivers. We assessed long-term (∼14-year) changes in liana abundance and forest dynamics within 36 1-ha permanent plots spanning ∼600 km2 of undisturbed rainforest in central Amazonia. Within each plot, we counted each liana stem (≥2 cm diameter) and measured its diameter at 1.3 m height, and then used these data to estimate liana aboveground biomass. An initial liana survey was completed in 1997–1999 and then repeated in 2012, using identical methods. Liana abundance in the plots increased by an average of 1.00% ± 0.88% per year, leading to a highly significant (t = 6.58, df = 35, P < 0.00001) increase in liana stem numbers. Liana biomass rose more slowly over time (0.32% ± 1.37% per year) and the mean difference between the two sampling intervals was nonsignificant (t = 1.46, df = 35, P = 0.15; paired t tests). Liana size distributions shifted significantly (χ2 = 191, df = 8, P < 0.0001; Chi-square test for independence) between censuses, mainly as a result of a nearly 40% increase in the number of smaller (2–3 cm diameter) lianas, suggesting that lianas recruited rapidly during the study. We used long-term data on rainfall and forest dynamics from our study site to test hypotheses about potential drivers of change in liana communities. Lianas generally increase with rainfall seasonality, but we found no significant trends over time (1997–2012) in five rainfall parameters (total annual rainfall, dry-season rainfall, wet-season rainfall, number of very dry months, CV of monthly rainfall). However, rates of tree mortality and recruitment have increased significantly over time in our plots, and general linear mixed-effect models suggested that lianas were more abundant at sites with higher tree mortality and flatter topography. Rising concentrations of atmospheric CO2, which may stimulate liana growth, might also have promoted liana increases. Our findings clearly support the view that lianas are increasing in abundance in old-growth tropical forests, possibly in response to accelerating forest dynamics and rising CO2 concentrations. The aboveground biomass of trees was lowest in plots with abundant lianas, suggesting that lianas could reduce forest carbon storage and potentially alter forest dynamics if they continue to proliferate.

In tropical forests, lianas (woody vines) are important structural parasites of trees. We assessed the effects of forest fragmentation, treefall disturbance, soils, and stand attributes on liana communities in central Amazonian rain forests. Over 27 500 liana stems (≥2 cm diameter at breast height [dbh]) were recorded in 27 1-ha plots in continuous forest and 42 plots in 10 forest fragments ranging from 1 to 100 ha in area. For each plot, an index of forest disturbance was determined from a 20-yr study of tree-community dynamics, and 19 soil-texture and chemistry parameters were derived from soil surface samples (top 20 cm). Liana abundance was 187–701 stems/ha, and liana aboveground dry biomass varied from 3.7 to 12.3 Mg/ha. Liana abundance increased significantly near forest edges and was significantly positively associated with forest disturbance and significantly negatively associated with tree biomass. Liana biomass was similarly associated with disturbance and tree biomass but also increased signifi...

In 1997, the Amazon Basin experienced an exceptionally severe El Nino drought. We assessed ef- fects of this rare event on mortality rates of trees in intact rain forest based on data from permanent plots. Long-term (5- to 13-year) mortality rates averaged only 1.12% per year prior to the drought. During the drought year, annual mortality jumped to 1.91% but abruptly fell back to 1.23% in the year following El Nino. Trees dying during the drought did not differ significantly in size or species composition from those that died previously, and there was no detectable effect of soil texture on mortality rates. These results suggest that intact Amazonian rainforests are relatively resistant to severe El Nino events.

Amazonian forests are experiencing rapid, unprecedented changes that are having major impacts on wildlife, regional hydrology and the global climate. Rates of deforestation and logging have accelerated in recent years and patterns of forest loss are changing, with extensive new highways providing conduits for settlers and loggers into the heart of the Amazon basin. These myriad changes are causing widespread fragmentation of forests. Fragmented landscapes in the Amazon experience diverse changes in forest dynamics, structure, composition and microclimate, and are highly vulnerable to droughts and fires—alterations that negatively affect a wide variety of animal species. In human-dominated lands intensive hunting may interact synergistically with fragmentation to further threaten wildlife populations.

The abilities of species to use the matrix of modified habitats surrounding forest fragments may aAect their vulnerability in fragmented landscapes. We used long-term (up to 19-year) studies of four animal groups in central Amazonia to test whether species’ abundances in the matrix were correlated with their relative extinction proneness in forest fragments. The four groups, birds, frogs, small mammals, and ants, had varying overall responses to fragmentation: species richness of small mammals and frogs increased after fragment isolation, whereas that of birds and ants decreased. For all four groups, a high proportion of nominally primary-forest species were detected in matrix habitats, with 8‐25% of species in each group found exclusively in the matrix. The three vertebrate groups (birds, small mammals, frogs) exhibited positive and significant correlations between matrix abundance and vulnerability to fragmentation, suggesting that species that avoid the matrix tend to decline or disappear in fragments, while those that tolerate or exploit the matrix often remain stable or increase. These results highlight the importance of the matrix in the dynamics and composition of vertebrate communities in tropical forest remnants, and have important implications for the management of fragmented landscapes. # 1999 Elsevier Science Ltd. All rights reserved.

Above-ground dry biomass of living trees including palms was estimated in 65 1 ha plots spanning a 1000 km 2 landscape in central Amazonia. The study area was located on heavily weathered, nutrient-poor soils that are widespread in the Amazon region. Biomass values were derived by measuring the diameter-at-breast-height (DBH) of all10 cm trees in each plot, then using an allometric equation and correction factor for small trees to estimate total tree biomass. Detailed information on soil texture, organic carbon, available water capacity, pH, macro- and micro-nutrients, and trace elements was collected from soil surface samples (0‐20 cm) in each plot, while slope was measured with a clinometer. Biomass estimates varied more than two-fold, from 231 to 492 metric tons ha ˇ1 , with a mean of 356 47 tons ha ˇ1 . Simple correlations with stringent (p < 0.006) Bonferroni corrections suggested that biomass was positively associated with total N, total exchangeable bases, K a ,M g 2a , clay, and organic C in soils, and negatively associated with Zn a , aluminum saturation, and sand. An ordination analysis revealed one major and several minor soil gradients in the study area, with the main gradient discriminating sites with varying proportions of clay (with clayey soils having higher concentrations of total N, organic C, most cations, and lower aluminum saturation and less sand). A multiple regression analysis revealed that the major clay-nutrient gradient was the only significant predictor, with the model explaining 32.3% of the total variation in biomass. Results of the analysis suggest that soil-fertility parameters can account for a third or more of the variation in above-ground biomass in Amazonian terra-firme forests. We suggest that, because the conversion of forest to pasture tends to reduce the nitrogen, clay, organic carbon, and nutrient contents of soils, forests that regenerate on formerly cleared lands may have lower biomass than the original forest, especially in areas with low soil fertility. # 1999 Elsevier Science B.V. All rights reserved.

We wish to clarify some concepts in the recent article “Unique, all-taxa survey in Costa Rica ‘self-destructs’ ” (News, [9 May, p. 893][1]) by Jocelyn Kaiser. The funding opportunity generated by the All-Taxa Biological Inventory (ATBI) was indeed restructured into a new set of national