Match!

Ecological Meltdown in Predator-Free Forest Fragments

Published on Nov 30, 2001in Science41.037
· DOI :10.1126/science.1064397
John Terborgh78
Estimated H-index: 78
(Duke University),
Lawrence Lopez4
Estimated H-index: 4
(FIU: Florida International University)
+ 8 AuthorsLuis Balbas1
Estimated H-index: 1
Sources
Abstract
The manner in which terrestrial ecosystems are regulated is controversial. The “top-down” school holds that predators limit herbivores and thereby prevent them from overexploiting vegetation. “Bottom-up” proponents stress the role of plant chemical defenses in limiting plant depredation by herbivores. A set of predator-free islands created by a hydroelectric impoundment in Venezuela allows a test of these competing world views. Limited area restricts the fauna of small (0.25 to 0.9 hectare) islands to predators of invertebrates (birds, lizards, anurans, and spiders), seed predators (rodents), and herbivores (howler monkeys, iguanas, and leaf-cutter ants). Predators of vertebrates are absent, and densities of rodents, howler monkeys, iguanas, and leaf-cutter ants are 10 to 100 times greater than on the nearby mainland, suggesting that predators normally limit their populations. The densities of seedlings and saplings of canopy trees are severely reduced on herbivore-affected islands, providing evidence of a trophic cascade unleashed in the absence of top-down regulation.
Figures & Tables
  • References (22)
  • Citations (1088)
📖 Papers frequently viewed together
1,151 Citations
11.3k Citations
25.4k Citations
78% of Scinapse members use related papers. After signing in, all features are FREE.
References22
Newest
#1Madhu Rao (Duke University)H-Index: 16
#2John Terborgh (Duke University)H-Index: 78
Last. Percy NuñezH-Index: 7
view all 3 authors...
: Understanding processes driving population declines and, ultimately, species loss in forest isolates has significant implications for the long-term maintenance of species diversity. We investigated a potential mechanism driving loss of plant species in small, medium, and large land-bridge islands in Lago Guri, a 4300-km2 hydroelectric impoundment in the State of Bolivar, Venezuela. Our hypothesis was that elevated Atta ( leaf-cutter ants) herbivory on small Guri islands, attributable to releas...
59 CitationsSource
#1Kalan Ickes (LSU: Louisiana State University)H-Index: 12
#2Saara J. DeWalt (LSU: Louisiana State University)H-Index: 25
Last. S. Appanah (Forest Research Institute Malaysia)H-Index: 1
view all 3 authors...
Large mammals often play important roles in determining the struc- ture and composition of plant communities. This study focused on the extent to which wild pigs (Sus scrofa) influence the dynamics of tree seedlings and saplings in a lowland rain forest at Pasoh Forest Reserve in West Malaysia. Native wild pigs are common in the study area and may significantly influence growth and survivorship of woody plants in the understorey through several activities - namely, nest building, soil rooting an...
76 CitationsSource
#1Lauri Oksanen (Umeå University)H-Index: 43
#2Tarja Oksanen (Umeå University)H-Index: 27
abstract: Hypotheses on trophic dynamics in terrestrial ecosystems fall into two major categories: those in which plants are assumed to be invulnerable to their consumers and those in which the build‐up of plant biomass is assumed to require top‐down control of folivores. The hypothesis of exploitation ecosystems (EEH) belongs to the latter category and focuses particularly on the consequences of the high energetic costs of maintenance of endotherms. Carnivorous endotherms require relatively hig...
284 CitationsSource
The potential role of predation as a factor underlying variation in leaf-cutter ant (Atta sp.) densities was investigated on recently isolated land-bridge islands in Lago Guri, Venezuela. A survey of mature Atta colonies revealed a sharp increase in densities on small and medium islands (5.6 and 2.3 colonies ha-' respectively) compared to large islands (0.72 colonies ha-') and the mainland (0 nests in 5.5 ha). Incipient colonies showed the reverse trend with higher densities on larger landmasses...
58 CitationsSource
#1Oswald J. SchmitzH-Index: 51
#2Peter A. HambäckH-Index: 27
Last. Andrew P. BeckermanH-Index: 33
view all 3 authors...
abstract: We present a quantitative synthesis of trophic cascades in terrestrial systems using data from 41 studies, reporting 60 independent tests. The studies covered a wide range of taxa in various terrestrial systems with varying degrees of species diversity. We quantified the average magnitude of direct effects of carnivores on herbivore prey and indirect effects of carnivores on plants. We examined how the effect magnitudes varied with type of carnivores in the study system, food web diver...
743 CitationsSource
#1Michael L. PaceH-Index: 73
#2Jonathan J. ColeH-Index: 84
Last. James F. Kitchell (UW: University of Wisconsin-Madison)H-Index: 66
view all 4 authors...
Abstract New studies are documenting trophic cascades in theoretically unlikely systems such as tropical forests and the open ocean. Together with increasing evidence of cascades, there is a deepening understanding of the conditions that promote and inhibit the transmission of predatory effects. These conditions include the relative productivity of ecosystems, presence of refuges and the potential for compensation. However, trophic cascades are also altered by humans. Analyses of the extirpation...
1,045 CitationsSource
This paper evaluates the multiple factors that determine the production of plant biomass and its distribution among producers and various trophic groups of con_ ?^)^ Osumers. In rough order of their importance, water and nutrient availability, factors 0*S that deter herbivores (plant defenses, environmental heterogeneity and disturbance, nutrient stoichiometry), and consumption by herbivores appear to be the most universal determinants of the production and distribution of plant biomass. In some...
399 CitationsSource
Trophic cascades have been the subject for considerable research during the last decade. A review of the literature suggests that trophic cascades have been observed in many kinds of systems and organisms. However, the extent to which trophic cascades have community-wide effects (e.g. affecting total primary producer biomass density) is only indisputably demonstrated in aquatic systems. The lack of unequivocal evidence for community-wide trophic cascades from terrestrial systems may be due to (1...
202 CitationsSource
#1John Terborgh (Duke University)H-Index: 78
#2Lawrence LopezH-Index: 4
Last. S José Tello (MU: University of Missouri)H-Index: 1
view all 3 authors...
We report on the bird communities of a set of 12 7-yr-old forested land- bridge islands in Lago Guri, a 4300 km2 hydroelectric impoundment in the State of Bolivar, Venezuela. Birds were censused on all islands and at mainland control sites by spot mapping in 1993, and via point counts in 1995. Instead of orderly "nested sets" of species on landmasses of graded size, the species composition of small (- 1 ha) and medium (11-12 ha) islands was highly variable. Spot mapping substantiated the occurre...
82 CitationsSource
#1William J. McSheaH-Index: 35
#2H. Brian UnderwoodH-Index: 2
Last. John H. RappoleH-Index: 24
view all 3 authors...
328 Citations
Cited By1088
Newest
Coyotes (Canis latrans) and red fox (Vulpes vulpes) are both generalist predators presently found in the Northeastern United States. This study aimed to identify major prey items of both species in suburban New York, investigate consumption of anthropogenic resources, and examine seasonal changes in diet. Scat samples were collected from 2017 to 2018 for coyotes, and from 2011 to 2012 for red fox. Hairs, feathers, bone fragments and other scat components were classified by comparison with refere...
Source
#1José M. Fedriani (CSIC: Spanish National Research Council)H-Index: 23
#2Daniel Ayllón (Complutense University of Madrid)H-Index: 13
Last. Volker Grimm (Helmholtz Centre for Environmental Research - UFZ)H-Index: 52
view all 4 authors...
Source
#1Tierra Smiley Evans (UC Davis: University of California, Davis)H-Index: 3
#2Theingi Win MyatH-Index: 3
Last. Christine K. Johnson (UC Davis: University of California, Davis)H-Index: 19
view all 15 authors...
Source
Source
#1Blai Vidiella Rocamora (UPF: Pompeu Fabra University)
#2Sergi ValverdeH-Index: 12
Last. Josep SardanyésH-Index: 2
view all 4 authors...
Transients in ecology are extremely important since they determine how equilibria are approached. The debate on the dynamic stability of ecosystems has been largely focused on equilibrium states. However, since ecosystems are constantly changing due to climate conditions or to perturbations such as the climate crisis or anthropogenic actions (habitat destruction, deforestation, or defaunation), it is important to study how dynamics can proceed till equilibria. In this contribution we investigate...
Source
#1Jessica Cheok (JCU: James Cook University)H-Index: 2
#2Rebecca Weeks (JCU: James Cook University)H-Index: 15
Last. Robert L. Pressey (JCU: James Cook University)H-Index: 74
view all 4 authors...
Abstract Problems of scale abound in the governance of complex social-ecological systems. Conservation governance, for example, typically occurs at a single scale, but needs to inform governance and action at other scales to be truly effective at achieving social and ecological outcomes. This process is conventionally conceived as unidirectional – either scaling down or scaling up – in the way it both exploits and creates the natural, social, human, institutional, and financial resources and ben...
Source
#1Leo Ohyama (UCF: University of Central Florida)
#2Joshua R. King (UCF: University of Central Florida)H-Index: 13
Last. David G. Jenkins (UCF: University of Central Florida)H-Index: 28
view all 3 authors...
Ants are a widespread group of ecologically important insects. Therefore, ants that are important predators of other ants are likely to play key roles by changing the abundance and impacts of their prey. Familiar arthropod predators, like army ants, are known for their overwhelming raids on invertebrate prey but are limited to mostly tropical systems. Thief ants (Genus: Solenopsis Westwood) are a cosmopolitan group of mostly subterranean ants found in a wide variety of ecosystem types. They are ...
Source
#1Joseph Reustle (A&M-CC: Texas A&M University–Corpus Christi)H-Index: 1
#2Delbert Lee Smee (USA: University of South Alabama)
Source
#1Valentina Oberosler (UNIPV: University of Pavia)H-Index: 2
#2Simone TenanH-Index: 8
Last. Francesco Rovero (UniFI: University of Florence)H-Index: 30
view all 4 authors...
Protected areas (PAs) in the tropics are vulnerable to human encroachment, and, despite formal protection, they do not fully mitigate anthropogenic threats to habitats and biodiversity. However, attempts to quantify the effectiveness of PAs and to understand the status and changes of wildlife populations in relation to protection efficiency remain limited. Here, we used camera-trapping data collected over 8 consecutive years (2009-2016) to investigate the yearly occurrences of medium-to-large ma...
Source
#1Jillian R. Stark (Pace University)
#2Matthew E. Aiello-Lammens (Pace University)H-Index: 13
Last. Melissa M. Grigione (Pace University)H-Index: 8
view all 3 authors...
The presence of human activity and development affects the distribution and behavior of carnivore species in various ways. It is necessary to examine the effects of urbanization and associated habitat fragmentation on the spatial ecology of predators, in order to develop a comprehensive understanding and formulate a proactive approach towards biodiversity protection in such areas. In this study, we observed patterns of occurrence and activity of carnivores in four preserves in metropolitan the N...
Source