Increasing isolation reduces predator:prey species richness ratios in aquatic food webs

Shulman, Rachel S.; Chase, Jonathan M.

doi:10.1111/j.0030-1299.2007.14690.x

Cited by 35 publications

(15 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Th e potential for environmental perturbations to have disproportionate eff ects on large-bodied, high trophic level taxa compared to smaller, lower trophic level taxa is an emerging generality (Petchey et al 1999, Gardner et al 2011, Ledger et al 2012, but the pattern is somewhat at odds with a long-held ecological belief. Whereas the theory of predator:prey ratio invariance suggests that the number of predator taxa per prey taxon should remain constant as the membership of local food webs increases or decreases (Cohen 1977, Jeff ries and Lawton 1985, Warren and Gaston 1992, but see Wilson 1996, our work and that of others (Shulman and Chase 2007) suggests that this may not always be the case, particularly in spatially compressed, isolated, or otherwise perturbed habitats. We found that local communities in smaller stream segments supported ca 25% fewer predator taxa per prey compared to larger perennial stream segments.…”

Section: Effects Of Habitat Size On Food Web Structurementioning

confidence: 63%

Habitat size influences food web structure in drying streams

et al. 2014

View full text Add to dashboard Cite

Biodiversity in running waters is threatened by an increased severity and incidence of low‐flow extremes resulting from global climate change and a growing human demand for freshwater resources. Although it is unknown how and to what extent riverine communities will change in the face of these threats, considerable insight will be gained from efforts aimed at quantifying habitat size‐related controls on the trophic relationships among taxa in streams experiencing extreme flow loss. Here we report on a detailed space‐for‐time survey of replicate stream food webs sampled along the perennial‐ to‐drying continuum in each of fourteen different intermittent South Island, New Zealand streams. We quantified several structural attributes of food webs at fifty‐eight sites, including two taxonomically‐based metrics (web size, predator:prey ratio) and three stable isotope‐based metrics (food chain length [FCL], trophic area, δ13C range); we also quantified habitat size‐, disturbance‐, and resource‐related covariates at each site. Food web structure varied widely across sample sites within and across study streams and much of this variation was explained by habitat size. Consistent with our predictions, we found that food webs became smaller (ca 30 to ca 15 taxa, ca 20‐fold reduction in stable isotope‐based trophic area) and shorter (maximum trophic position [FCL] from 4.1 to 2.0, 25% reduction in predator:prey ratio) as we moved from the largest to smaller habitats. These results, and a comparison of our findings with those from a similar assessment conducted in perennial streams, suggest that there are perturbation thresholds which may trigger food web collapse when exceeded, and further imply that food webs may ultimately be ‘sized’ to minimum flows rather than average flow conditions. Our work provides a basis for making general predictions about how habitat contraction, and flow loss in particular, may affect communities and additionally provides insight on mechanisms warranting further attention.

show abstract

Section: Effects Of Habitat Size On Food Web Structurementioning

confidence: 63%

Habitat size influences food web structure in drying streams

et al. 2014

View full text Add to dashboard Cite

show abstract

“…While the effects of fragmentation on metacommunity diversity are only tentatively understood (Forbes and Chase 2002, Gonzalez 2005, Layman et al 2007, Shulman and Chase 2007, Cagnolo et al 2009) we conclude that habitat quality at the individual patch level and the proximity of high-quality habitat within the network are important determinants of network biodiversity. These results reinforce the conclusion that habitat heterogeneity within the landscape has a strong influence on patterns of diversity (Trzcinski et al 1999, Heikkinen et al 2004) and that it interacts with network configuration to effect diversity and in certain circumstances it may prove to be as important as the effects of isolation and area (Thomas et al 2001, Fleishman et al 2002.…”

Section: Discussionmentioning

confidence: 75%

Metacommunity diversity depends on connectivity and patch arrangement in heterogeneous habitat networks

Chisholm¹,

Lindo²,

Gonzalez³

2010

Ecography

116

View full text Add to dashboard Cite

Connectivity is critical to the maintenance of biodiversity in fragmented landscapes, but its effects differ depending on the arrangement of linkages within a habitat network. Additionally, heterogeneity in habitat quality within the habitat network can alter patterns of diversity at local and regional scales in the metacommunity. Using a controlled experiment we examined the interactive effects of habitat connectivity, network form (linear vs square), and habitat patch quality on a moss‐inhabiting microarthropod community. We fragmented moss habitat while controlling for habitat loss, and altered habitat patch quality by regulating moisture conditions in landscapes differing in patch arrangement. Habitat patch quality had a significant effect on patterns of species richness, extinction, abundance and biomass. The effects of network form on diversity were strongest in heterogeneous landscapes. Gamma and beta diversity were greatest in continuous and linear landscapes. However, linear habitat networks showed marked patch specific edge effects that were detrimental to diversity under heterogeneous conditions. We provide direct evidence that habitat network structure impacts species community properties through mass effects, that are most evident when heterogeneity in habitat patch quality is present within the network. We conclude that habitat quality at the individual patch level and the distribution of high‐quality habitat within the network are important factors affecting biodiversity in metacommunities.

show abstract

“…Predators generally have lower abundances than their prey (Spencer 2000) due to inefficient energy transfer among trophic levels. This lower abundance also results in both greater susceptibility to local extinctions due to small population sizes and fewer dispersers colonizing open patches (Shulman & Chase 2007). Thus at larger scales, predator species are likely to be included due to increased sampling (Holt et al 1999;Hoyle 2004), whereas prey species saturate at much smaller scales.…”

Section: O N C L U S I O N Smentioning

confidence: 99%

Plant genetics shapes inquiline community structure across spatial scales

2009

View full text Add to dashboard Cite

Recent research in community genetics has examined the effects of intraspecific genetic variation on species diversity in local communities. However, communities can be structured by a combination of both local and regional processes and to date, few community genetics studies have examined whether the effects of instraspecific genetic variation are consistent across levels of diversity. In this study, we ask whether host-plant genetic variation structures communities of arthropod inquilines within distinct habitat patches--rosette leaf galls on tall goldenrod (Solidago altissima). We found that genetic variation determined inquiline diversity at both local and regional spatial scales, but that trophic-level responses varied independently of one another. This result suggests that herbivores and predators likely respond to heritable plant traits at different spatial scales. Together, our results show that incorporating spatial scale is essential for predicting the effects of genetically variable traits on different trophic levels and levels of diversity within the communities that depend on host plants.

show abstract

Increasing isolation reduces predator:prey species richness ratios in aquatic food webs

Cited by 35 publications

References 45 publications

Habitat size influences food web structure in drying streams

Habitat size influences food web structure in drying streams

Metacommunity diversity depends on connectivity and patch arrangement in heterogeneous habitat networks

Plant genetics shapes inquiline community structure across spatial scales

Contact Info

Product

Resources

About