Fire as a global ‘herbivore’: the ecology and evolution of flammable ecosystems

Trends in Ecology & Evolution, Journal Year: 2005, Volume and Issue: 20(7), P. 387 - 394

Published: May 5, 2005

Language: Английский

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Trophic Cascades in a Formerly Cod-Dominated Ecosystem

Science, Journal Year: 2005, Volume and Issue: 308(5728), P. 1621 - 1623

Published: June 9, 2005

Removal of top predators from ecosystems can result in cascading effects through the trophic levels below, completely restructuring food web. Cascades have been observed small-scale or simple webs, but not large, complex, open-ocean ecosystems. Using data spanning many decades a once cod-dominated northwest Atlantic ecosystem, we demonstrate cascade large marine ecosystem. Several cod stocks other geographic areas also collapsed without recovery, suggesting existence cascades these systems.

Language: Английский

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Viewing invasive species removal in a whole-ecosystem context

Trends in Ecology & Evolution, Journal Year: 2001, Volume and Issue: 16(8), P. 454 - 459

Published: Aug. 1, 2001

Language: Английский

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Trophic cascades: the primacy of trait‐mediated indirect interactions

Ecology Letters, Journal Year: 2004, Volume and Issue: 7(2), P. 153 - 163

Published: Feb. 1, 2004

Abstract Trophic cascades are textbook examples of predator indirect effects on ecological systems. Yet there is considerable debate about their nature, strength and overall importance. This stems in part from continued uncertainty the ultimate mechanisms driving cascading effects. We present a synthesis empirical evidence support one possible mechanism: foraging‐predation risk trade‐offs undertaken by intermediary species. show that simple trade‐off behaviour can lead to both positive negative predators plant resources hence explain contingency nature among Thus, predicting sign effect simply requires knowledge habitat resource use prey with regard predators’ presence, hunting mode. The allows us postulate hypothesis for new conceptualization trophic which be viewed as an between intervening In this context, different apply rules engagement based mode use. These then determine whether behavioural persist or attenuate at level food chain.

Language: Английский

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A cross‐ecosystem comparison of the strength of trophic cascades

Ecology Letters, Journal Year: 2002, Volume and Issue: 5(6), P. 785 - 791

Published: Nov. 1, 2002

Abstract Although trophic cascades (indirect effects of predators on plants via herbivores) occur in a wide variety food webs, the magnitudes their are often quite variable. We compared responses herbivore and plant communities to predator manipulations 102 field experiments six different ecosystems: lentic (lake pond), marine, stream benthos, marine plankton, terrestrial (grasslands agricultural fields). Predator varied considerably among systems were strongest benthos weakest plankton webs. herbivores generally larger more variable than plants, suggesting that become attenuated at plant–herbivore interface. Top‐down control biomass was stronger water land; however, differences five aquatic webs as great those between wet dry systems.

Language: Английский

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Cascading top‐down effects of changing oceanic predator abundances

Journal of Animal Ecology, Journal Year: 2009, Volume and Issue: 78(4), P. 699 - 714

Published: March 9, 2009

Summary Top‐down control can be an important determinant of ecosystem structure and function, but in oceanic ecosystems, where cascading effects predator depletions, recoveries, invasions could significant, such had rarely been demonstrated until recently. Here we synthesize the evidence for top‐down that has emerged over last decade, focusing on large, high trophic‐level predators inhabiting continental shelves, seas, open ocean. In these controlled manipulations are largely infeasible, ‘pseudo‐experimental’ analyses predator–prey interactions treat independent populations as ‘replicates’, temporal or spatial contrasts climate ‘treatments’, increasingly employed to help disentangle from environmental variation noise. Substantial reductions marine mammals, sharks, piscivorous fishes have led mesopredator invertebrate increases. Conversely, abundant suppressed prey abundances. Predation also inhibited recovery depleted species, sometimes through role reversals. Trophic cascades initiated by linking neritic food webs, seem inconsistent pelagic realm with often attenuating at plankton. is not uniformly strong ocean, appears contingent intensity nature perturbations Predator diversity may dampen except nonselective fisheries deplete entire functional groups. other cases, simultaneous exploitation inhibit responses. Explicit consideration anthropogenic modifications foodwebs should inform predictions about trophic control. Synthesis applications . Oceanic socio‐economic, conservation, management implications mesopredators invertebrates assume dominance, overexploited impaired. Continued research aimed integrating across levels needed understand forecast changing abundances, relative strength bottom‐up control, intensifying stressors change.

Language: Английский

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Biodiversity and ecosystem function: the consumer connection

Oikos, Journal Year: 2002, Volume and Issue: 99(2), P. 201 - 219

Published: Nov. 1, 2002

Proposed links between biodiversity and ecosystem processes have generated intense interest controversy in recent years. With few exceptions, however, empirical studies focused on grassland plants laboratory aquatic microbial systems, whereas there has been little attention to how changing animal diversity may influence processes. Meanwhile, a separate research tradition demonstrated strong top‐down forcing many but considered the role of these only tangentially. Integration directions is necessary for more complete understanding both areas. Several considerations suggest that multi‐level food webs can important effects be qualitatively different than those mediated by plants. First, extinctions tend biased trophic level: higher‐level consumers are less diverse, abundant, under stronger anthropogenic pressure average wild plants, thus face greater risk extinction. Second, unlike often impacts ecosystems disproportionate their abundance. Thus, an early consequence declining will skewed structure, potentially reducing influence. Third, where predators remain at lower levels change effectiveness predation penetrance cascades trait potential compensation among species within level. The mostly indirect evidence available provides some support this prediction. Yet functional rarely tested experimentally. Evaluating loss function requires expanding scope current experimental webs. A central challenge doing so, evaluating importance specifically, distribution interaction strengths natural communities they with community composition. Although topology most real extremely complex, it not all clear much complexity translates dynamic linkages aggregate biomass Finally, need detailed data patterns from (community “disassembly” rules).

Language: Английский

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WHAT DETERMINES THE STRENGTH OF A TROPHIC CASCADE?

Ecology, Journal Year: 2005, Volume and Issue: 86(2), P. 528 - 537

Published: Feb. 1, 2005

Trophic cascades have been documented in a diversity of ecological systems and can be important determining biomass distribution within community. To date, the literature on trophic has focused whether which occur. Many biological (e.g., productivity : ratios) methodological experiment size or duration) factors vary with ecosystem data were collected, but type, per se, does not provide mechanistic insights into controlling cascade strength. Here, we tested various hypotheses about why occur what determines their magnitude using from 114 studies that measured indirect effects predators plant community seven aquatic terrestrial ecosystems. Using meta-analysis, examined relationship between effect predator manipulation plants 18 quantified these studies. We found, contrast to predictions, high system low species do consistently generate larger cascades. A combination herbivore metabolic taxonomy (vertebrate vs. invertebrate) explained 31% variation strength among all Within systems, 18% was similar characteristics. across strongest occurred association invertebrate herbivores endothermic vertebrate predators. These associations may result true differences different physiological requirements bias organisms studied systems. Thus, although described by characteristics herbivores, future research must further examine

Language: Английский

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Landscapes of Fear: Spatial Patterns of Risk Perception and Response

Trends in Ecology & Evolution, Journal Year: 2019, Volume and Issue: 34(4), P. 355 - 368

Published: Feb. 10, 2019

Language: Английский

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All wet or dried up? Real differences between aquatic and terrestrial food webs

Proceedings of the Royal Society B Biological Sciences, Journal Year: 2005, Volume and Issue: 273(1582), P. 1 - 9

Published: Nov. 29, 2005

Ecologists have greatly advanced our understanding of the processes that regulate trophic structure and dynamics in ecosystems. However, causes systematic variation among ecosystems remain controversial poorly elucidated. Contrasts between aquatic terrestrial particular inspired much speculation, but only recent empirical quantification. Here, we review evidence for differences energy flow biomass partitioning producers herbivores, detritus decomposers, higher levels. The magnitudes different pathways vary considerably, with less herbivory, more decomposers detrital accumulation on land. Aquatic-terrestrial are consistent across global range primary productivity, indicating structural contrasts two systems preserved despite large input. We argue variable selective forces drive plant allocation patterns environments propagate upward to shape food webs. small size lack tissues phytoplankton mean achieve faster growth rates nutritious heterotrophs than their counterparts. Plankton webs also strongly size-structured, while position correlated most (and many benthic) habitats. available data indicate driven primarily by rate, nutritional quality autotrophs. Differences food-web architecture (food chain length, prevalence omnivory, specialization or anti-predator defences) may arise as a consequence character producer community.

Language: Английский

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