Effects of predator functional diversity on grassland ecosystem function

Schmitz, Oswald J.

doi:10.1890/08-1919.1

Cited by 132 publications

(137 citation statements)

References 36 publications

Supporting

Mentioning

129

Contrasting

Unclassified

Order By: Relevance

“…First, although our efforts focus on describing grasshopper abundance and species community composition with respect to plant nutritional (measured in terms of elements) and biomass traits, we realize that insect herbivore distributions and abundances can also interact and covary with a range of nonnutritional factors, including: vegetation structure and plant species composition (Haddad et al 2001, Joern 2004, resource complementation (Beckerman 2002), behavioral limits affecting local dispersal (With andCrist 1995, Haynes andCronin 2006), predation risk (Schmitz et al 1997, Cronin et al 2004, Danner and Joern 2004, Schmitz 2009, Hawlena and Schmitz 2010, and larger-scale landscape features than that studied here (Haynes et al 2007). Second, we acknowledge that what is measured in plants, and what is available to insect herbivores, are not necessarily equal.…”

Section: Discussionmentioning

confidence: 99%

Not just the usual suspects: Insect herbivore populations and communities are associated with multiple plant nutrients

Joern

Provin

Behmer

2012

Ecology

152

129

View full text Add to dashboard Cite

Abstract. The relationship between plant nutrient content and insect herbivore populations and community structure has long interested ecologists. Insect herbivores require multiple nutrients, but ecologists have focused mostly on nitrogen (an estimate of plant protein content), and more recently phosphorus (P); other nutrients have received little attention. Here we document nutrient variation in grass and forb samples from grassland habitats in central Nebraska using an elemental approach; in total we measured foliar concentrations of 12 elements (N and P, plus S, B, Ca, Mg, Na, K, Zn, Fe, Mn, and Cu). We detected significant variability among sites for N, P, Mg, Na, K, and Cu. We next used a model selection approach to explore how this nutritional variation and plant biomass correlate with grasshopper densities (collectively and at the feeding-guild level), and principal component analysis to explore nutrient correlations with grasshopper community species composition. When all grasshoppers were pooled, densities varied among sites, but only P was associated with abundance of the elements shown to vary between sites. Different responses occurred at the feeding-guild level. For grass specialists, densities were associated with N, plus P, Mg, and Na. For forb specialists, N and P were often associated with density, but associations with Na and K were also observed. Finally, mixed-feeder abundance was strongly associated with biomass, and to a lesser extent P, Mg, Na, and Cu. At the community level, B, Ca, Zn, and Cu, plus biomass, explained .30% of species composition variation. Our results confirm the positive association of N and P with insect herbivore populations, while suggesting a potential role for Mg, Na, and K. They also demonstrate the importance of exploring effects at the feeding-guild level. We hope our data motivate ecologists to think beyond N and P when considering plant nutrient effects on insect herbivores, and make a call for studies to examine functional responses of insect herbivores to dietary manipulation of Mg, Na, and K. Finally, our results demonstrate correlations between variation in nutrients and species assemblages, but factors not linked to plant nutrient quality or biomass likely explain most of the observed variation.

show abstract

Section: Discussionmentioning

confidence: 99%

Not just the usual suspects: Insect herbivore populations and communities are associated with multiple plant nutrients

Joern

Provin

Behmer

2012

Ecology

152

129

View full text Add to dashboard Cite

show abstract

“…1]). Previous studies reporting strong predator control over ecosystem function are often either from aquatic ecosystems, in which plant tissue is more nutritious and more easily decomposed than in terrestrial ecosystems, or from systems with large vertebrate carnivores (Oksanen and Oksanen 2000, Schmitz et al 2000, Shurin et al 2002, Borer et al 2005, Halpern et al 2006, Schmitz 2009), which may strictly control the density and behavior of large herbivores that effectively decrease plant production. The top-down effect of manipulation of small predators on ecosystem properties usually requires a long time (e.g., three years; Schmitz 2003Schmitz , 2008 to take place if simulated closely to nature.…”

Section: Role Of Predators In Ecosystem Functioningmentioning

confidence: 99%

“…The role of predator diversity in regulating plant and herbivore dynamics and ecosystem functioning is complex (Ives et al 2005, Duffy et al 2007, Bruno and Cardinale 2008, Letourneau et al 2009). Many reports show that increasing predator diversity can either strengthen or weaken the predator effect on other trophic levels (e.g., Losey and Denno 1998, Sinclair et al 2003, Byrnes et al 2006, Schmitz 2009). As found in plant diversity-ecosystem functioning relationships, mechanisms underlying positive effects of predator diversity on predation rate could include sampling effects and complementary use of prey taxa or foraging microhabitats.…”

Section: Introductionmentioning

confidence: 99%

A brown-world cascade in the dung decomposer food web of an alpine meadow: effects of predator interactions and warming

Duffy

Reich

et al. 2011

Ecological Monographs

109

113

View full text Add to dashboard Cite

Abstract. Top-down control has been extensively documented in food webs based on living plants, where predator limitation of herbivores can cascade to facilitate plant growth (the green-world hypothesis), particularly in grasslands and aquatic systems. Yet the ecosystem role of predators in detrital food webs is less explored, as is the potential effect of climate warming on detritus-based communities. We here show that predators have a ''brown-world'' role in decomposer communities via a cascading top-down control on plant growth, based on the results of an experiment that factorially manipulated presence and size of two predator species as well as temperature (warmed vs. unwarmed). The inclusion of predatory beetles significantly decreased abundance of coprophagous beetles and thus the rate of dung decomposition and productivity of plants growing surrounding the dung. Moreover, the magnitude of these decreases differed between predator species and, for dung loss, was temperature dependent. At ambient temperature, the larger predators tended to more strongly influence the dung loss rate than did the smaller predators; when both predators were present, the dung loss rate was higher relative to the treatments with the smaller predators but comparable to those with the larger ones, suggesting an antagonistic effect of predator interaction. However, warming substantially reduced dung decomposition rates and eliminated the effects of predation on dung decomposition. Although warming substantially decreased dung loss rates, warming only modestly reduced primary productivity. Consistent with these results, a second experiment exploring the influence of the two predator species and warming on dung loss over time revealed that predatory beetles significantly decreased the abundance of coprophagous beetles, which was positively correlated with dung loss rates. Moreover, experimental warming decreased the water content of dung and hence the survival of coprophagous beetles. These results confirm that the ''brown-world'' effect of predator beetles was due to cascading top-down control through coprophagous beetles to nutrient cycling and primary productivity. Our results also highlight potentially counterintuitive effects of climate warming. For example, global warming might significantly decrease animalmediated decomposition of organic matter and recycling of nutrients in a future warmed world.

show abstract

“…Predation is a pervasive process that can influence community organization (Paine 1966, Schmitz 1998, Duffy & Hay 2001 and ecosystem functioning (Schmitz 1998, Sih et al 1998, Schmitz 2009. A fundamental component of predation is the direct removal of prey, leading to reductions in the numerical abundance of prey populations (Murdoch et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Density- and trait-mediated effects of fish predators on amphipod grazers: potential indirect benefits for the giant kelp Macrocystis pyrifera

Pérez‐Matus¹,

Shima²

2010

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Indirect effects of predators on primary producers may arise when predators suppress herbivore abundance and/or alter the behaviour patterns of herbivores in ways that reduce grazing pressure. Most studies highlight the role of predators in reducing herbivore abundance (i.e. densitymediated interactions), while behavioural effects (i.e. trait-mediated interactions) induced by predators are less commonly considered and are often assumed to be of secondary importance. We used a mesocosm experiment to evaluate the consumptive and behavioural effects of 2 species of predatory fishes on amphipod grazers that feed and nest on the giant kelp Macrocystis pyrifera. Only one, Notolabrus celidotus, of the 2 predator species reduced grazer abundance. Although the second predator species, N. fucicola, did not affect grazer abundance directly, it significantly reduced the grazing efficiency of amphipods on blades of M. pyrifera. Our study illustrates how density-and trait-mediated interactions reduce grazer efficiency and provide potential indirect benefits to primary producers. To our knowledge, this is the first experimental evidence of a potential trophic cascade in kelp beds generated by consumptive and nonconsumptive effects. When considered alongside results of other studies that highlight positive effects of macroalgae on reef fish demographic rates, our results provide compelling evidence that mutualistic relationships may exist between kelp and associated predatory fishes.

show abstract

Effects of predator functional diversity on grassland ecosystem function

Cited by 132 publications

References 36 publications

Not just the usual suspects: Insect herbivore populations and communities are associated with multiple plant nutrients

Not just the usual suspects: Insect herbivore populations and communities are associated with multiple plant nutrients

A brown-world cascade in the dung decomposer food web of an alpine meadow: effects of predator interactions and warming

Density- and trait-mediated effects of fish predators on amphipod grazers: potential indirect benefits for the giant kelp Macrocystis pyrifera

Contact Info

Product

Resources

About