The Magnitude of Local Host Specif icity for Phytophagous Insects and its Implications for Estimates of Global Species Richness

Ødegaard, Frode; Diserud, Ola Håvard; Engen, Steinar; Aagaard, Kaare

doi:10.1046/j.1523-1739.2000.99393.x

Cited by 50 publications

(40 citation statements)

References 21 publications

(27 reference statements)

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“…The relation between our multiple-site similarity and Whittaker's b W is simply If, instead of species-sites data, we are studying host observations of, for example, phytophagous insect species on host plant species, the comparison of species compositions on different host plants can be performed by both similarity and host-specificity measures. The host specificity calculated from trophic interactions is defined as Ødegaard et al 2000;Novotny et al 2002), where S T is the total number of insect species found on T host plant species; S T is the average number of insect species associated with each host plant species; and T is the number of host plant species in the study. The product S T !T is thereby the total number of host observations.…”

Section: Methodsmentioning

confidence: 99%

A multiple-site similarity measure

2006

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Similarity measures are among the most intuitive and common measures for comparing two or more sites, or samples, with respect to their species overlap. A restriction of similarity measures is that they are limited to pairwise comparisons even in a multiple-site study. This work presents a multiple-site similarity measure that makes use of information on species shared by more than two sites and avoids the problem of covariance between pairwise similarities in a multiple-site study. Further, we show that our multiple-site similarity measure is related to b-diversity measures such as Whittaker's b-diversity. Similarity measures can also be used as descriptors of effective specialization of insects to host species by measuring similarity from host observations. Finally, we show that multiple-site similarity and host specificity are two sides of the same coin.

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Section: Methodsmentioning

confidence: 99%

A multiple-site similarity measure

2006

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“…Host specificity was measured as effective specialization (May 1990;Ødegaard et al 2000). The principle behind effective specialization of a plant's insect fauna is to weight each insect species in accordance with its degree of specialization on other plants in the community.…”

Section: Methodsmentioning

confidence: 99%

“…Host specialization among insects complicates the patterns of beta diversity, however. The effective specialization among tropical insect communities is probably as low as 5-10% (Basset et al 1996;Ødegaard et al 2000;Novotny et al 2002a), and it is unknown how the large proportion of generalists among tropical insects affects species turnover.…”

Section: Introductionmentioning

confidence: 99%

Host Specificity, Alpha- and Beta-Diversity of Phytophagous Beetles in Two Tropical Forests in Panama

Ødegaard

2006

Biodivers Conserv

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Abstract. Species diversity, host specificity and species turnover among phytophagous beetles were studied in the canopy of two tropical lowland forests in Panama with the use of canopy cranes. A sharp rainfall gradient occurs between the two sites located 80 km apart. The wetter forest is located in San Lorenzo Protected Area on the Caribbean side of the isthmus, and the drier forest is a part of the Parque Natural Metropolitano close to Panama City on the Pacific slope. Host specificity was measured as effective specialization and recorded by probability methods based on abundance categories and feeding records from a total of 102 species of trees and lianas equally distributed between the two sites. The total material collected included more than 65,000 beetles of 2462 species, of which 306 species were shared between the two sites. The wet forest was 37% more species rich than the dry forest due to more saproxylic species and flower visitors. Saproxylic species and flower visitors were also more host-specific in the wet forest. Leaf chewers showed similar levels of species richness and host specificity in both forests. The effective number of specialized species per plant species was higher in the wet forest. Higher levels of local alpha-and beta-diversity as well as host specificity based on present data from a tropical wet forest, suggests higher number of species at regional levels, a result that may have consequences for ecological estimates of global species richness.

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“…from vertebrate groups, to invertebrates, down to nematodes (e.g. see: Medellín & Soberón, 1999;Ødegaard et al , 2000;Lambshead & Boucher, 2003). In so far as we do know our species, we also have, for many taxa, inadequate knowledge of their global, regional, and even local distributions, a problem that Lomolino (2004) has labelled the Wallacean shortfall.…”

Section: Key Assumptions and Sensitivities (I) The Linnean And Wallacmentioning

confidence: 99%

Conservation Biogeography: assessment and prospect

Whittaker

Araújo

Jepson

et al. 2005

Diversity and Distributions

1,008

848

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There is general agreement among scientists that biodiversity is under assault on a global basis and that species are being lost at a greatly enhanced rate. This article examines the role played by biogeographical science in the emergence of conservation guidance and makes the case for the recognition of Conservation Biogeography as a key subfield of conservation biology delimited as: the application of biogeographical principles, theories, and analyses, being those concerned with the distributional dynamics of taxa individually and collectively, to problems concerning the conservation of biodiversity. Conservation biogeography thus encompasses both a substantial body of theory and analysis, and some of the most prominent planning frameworks used in conservation. Considerable advances in conservation guidelines have been made over the last few decades by applying biogeographical methods and principles. Herein we provide a critical review focussed on the sensitivity to assumptions inherent in the applications we examine. In particular, we focus on four inter-related factors: (i) scale dependency (both spatial and temporal); (ii) inadequacies in taxonomic and distributional data (the so-called Linnean and Wallacean shortfalls); (iii) effects of model structure and parameterisation; and (iv) inadequacies of theory. These generic problems are illustrated by reference to studies ranging from the application of historical biogeography, through island biogeography, and complementarity analyses to bioclimatic envelope modelling. There is a great deal of uncertainty inherent in predictive analyses in conservation biogeography and this area in particular presents considerable challenges.Protected area planning frameworks and their resulting map outputs are amongst the most powerful and influential applications within conservation biogeography, and at the global scale are characterised by the production, by a small number of prominent NGOs, of bespoke schemes, which serve both to mobilise funds and channel efforts in a highly targeted fashion. We provide a simple typology of protected area planning frameworks, with particular reference to the global scale, and provide a brief critique of some of their strengths and weaknesses. Finally, we discuss the importance, especially at regional scales, of developing more responsive analyses and models that integrate pattern (the compositionalist approach) and processes (the functionalist approach) such as range collapse and climate change, again noting the sensitivity of outcomes to starting assumptions. We make the case for the greater engagement of the biogeographical community in a programme of evaluation and refinement of all such schemes to test their robustness and their sensitivity to alternative conservation priorities and goals.

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The Magnitude of Local Host Specif icity for Phytophagous Insects and its Implications for Estimates of Global Species Richness

Cited by 50 publications

References 21 publications

A multiple-site similarity measure

A multiple-site similarity measure

Host Specificity, Alpha- and Beta-Diversity of Phytophagous Beetles in Two Tropical Forests in Panama

Conservation Biogeography: assessment and prospect

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