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Dive into the research topics where Thomas E. Lovejoy is active.

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Featured researches published by Thomas E. Lovejoy.


Nature | 2011

Primary forests are irreplaceable for sustaining tropical biodiversity

Luke Gibson; Tien Ming Lee; Lian Pin Koh; Barry W. Brook; Toby A. Gardner; Jos Barlow; Carlos A. Peres; William F. Laurance; Thomas E. Lovejoy; Navjot S. Sodhi

Human-driven land-use changes increasingly threaten biodiversity, particularly in tropical forests where both species diversity and human pressures on natural environments are high. The rapid conversion of tropical forests for agriculture, timber production and other uses has generated vast, human-dominated landscapes with potentially dire consequences for tropical biodiversity. Today, few truly undisturbed tropical forests exist, whereas those degraded by repeated logging and fires, as well as secondary and plantation forests, are rapidly expanding. Here we provide a global assessment of the impact of disturbance and land conversion on biodiversity in tropical forests using a meta-analysis of 138 studies. We analysed 2,220 pairwise comparisons of biodiversity values in primary forests (with little or no human disturbance) and disturbed forests. We found that biodiversity values were substantially lower in degraded forests, but that this varied considerably by geographic region, taxonomic group, ecological metric and disturbance type. Even after partly accounting for confounding colonization and succession effects due to the composition of surrounding habitats, isolation and time since disturbance, we find that most forms of forest degradation have an overwhelmingly detrimental effect on tropical biodiversity. Our results clearly indicate that when it comes to maintaining tropical biodiversity, there is no substitute for primary forests.


Biological Conservation | 1999

Matrix habitat and species richness in tropical forest remnants

Claude Gascon; Thomas E. Lovejoy; Richard O Bierregaard; Jay R Malcolm; Phillip C Stouffer; Heraldo L. Vasconcelos; William F. Laurance; Barbara Zimmerman; Mandy Tocher; Sérgio Borges

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.


BioScience | 1992

The biological dynamics of tropical rainforest fragments A prospective comparison of fragments and continuous forest

Richard O. Bierregaard; Thomas E. Lovejoy; Valerie Kapos; Angelo Augusto dos Santos; Roger W. Hutchings

Richard 0. Bierregaard Jr. is director of the Biological Dynamics of Forest Fragment Project at the National Museum of Natural History, Smithsonian Institution, Washington, DC 20560; his research focuses on avian community structure in Amazonian rainforests, particularly the responses of such communities to forest fragmentation. Thomas E. Lovejoy is the Assistant Secretary for External Affairs of the Smithsonian Institution, Washington, DC 20560. Valerie Kapos is a research associate in the Department of Botany, University of Cambridge, Cambridge CB2 3EA, United Kingdom and at the University of North Wales; her research is on water and nutrient relations and phenology of tropical deciduous trees and edge effects on environment and plant responses. Angelo Augusto dos Santos is the coordinator for international cooperation at Brazils National Institute for Amazonian Research (INPA) and the Brazilian co-principal investigator of BDFFP at the National Museum of Natural History, Smithsonian Institution, Washington, DC 20560; his research focuses on the structure and ecology of tropical rainforest fragments. Roger W. Hutchings is the field director of BDFFP, Ecologia/V-8, INPA, C.P. 478, 69.011 Manaus, AM, Brazil; his research interests include butterflies in tropical forest fragments and adjacent continuous forest, botanical ecology, and general conservation biology of tropical rainforests. A mosaic of small


Science Advances | 2015

Habitat fragmentation and its lasting impact on Earth's ecosystems

Nick M. Haddad; Lars A. Brudvig; Jean Clobert; Kendi F. Davies; Andrew Gonzalez; Robert D. Holt; Thomas E. Lovejoy; Joseph O. Sexton; M. P. Austin; Cathy D. Collins; Ellen I. Damschen; Robert M. Ewers; Bryan L. Foster; Clinton N. Jenkins; Andrew King; William F. Laurance; Douglas J. Levey; Chris Margules; Brett A. Melbourne; A. O. Nicholls; John L. Orrock; Dan Xia Song; J. R. G. Townshend

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.


Ecology | 2001

RAIN FOREST FRAGMENTATION AND THE STRUCTURE OF AMAZONIAN LIANA COMMUNITIES

William F. Laurance; Diego R. Pérez-Salicrup; Patricia Delamônica; Philip M. Fearnside; Sammya D'Angelo; Adriano Jerozolinski; Luciano Pohl; Thomas E. Lovejoy

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...


Forest Ecology and Management | 1999

Relationship between soils and Amazon forest biomass: a landscape-scale study

William F. Laurance; Philip M. Fearnside; Susan G. Laurance; Patricia Delamônica; Thomas E. Lovejoy; Judy M. Rankin-de Merona; Jeffrey Q. Chambers; Claude Gascon

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.


Nature | 2000

Conservation: Rainforest fragmentation kills big trees

William F. Laurance; Patricia Delamônica; Susan G. Laurance; Heraldo L. Vasconcelos; Thomas E. Lovejoy

In tropical forests, large canopy and emergent trees are crucial sources of fruits, flowers and shelter for animal populations. They are also reproductively dominant and strongly influence forest structure, composition, gap dynamics, hydrology and carbon storage. Here we show that forest fragmentation in central Amazonia is having a disproportionately severe effect on large trees, the loss of which will have major impacts on the rainforest ecosystem.


Nature | 2000

Rainforest fragmentation kills big trees.

William F. Laurance; Patricia Delamônica; Susan G. Laurance; Heraldo L. Vasconcelos; Thomas E. Lovejoy

In tropical forests, large canopy and emergent trees are crucial sources of fruits, flowers and shelter for animal populations. They are also reproductively dominant and strongly influence forest structure, composition, gap dynamics, hydrology and carbon storage. Here we show that forest fragmentation in central Amazonia is having a disproportionately severe effect on large trees, the loss of which will have major impacts on the rainforest ecosystem.


Proceedings of the National Academy of Sciences of the United States of America | 2006

Rapid decay of tree-community composition in Amazonian forest fragments

William F. Laurance; Henrique E. M. Nascimento; Susan G. Laurance; Ana Andrade; Jose E. L. S. Ribeiro; Juan Pablo Giraldo; Thomas E. Lovejoy; Richard Condit; Jérôme Chave; Kyle E. Harms; Sammya D'Angelo

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.


Proceedings of the National Academy of Sciences of the United States of America | 2003

Rates of species loss from Amazonian forest fragments

Goncalo N. Ferraz; Gareth J. Russell; Philip C. Stouffer; Richard O. Bierregaard; Stuart L. Pimm; Thomas E. Lovejoy

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 <15 years, too short a time for implementing conservation measures.

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Ana Andrade

Smithsonian Tropical Research Institute

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José Luís C. Camargo

Smithsonian Tropical Research Institute

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Heraldo L. Vasconcelos

Federal University of Uberlandia

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