Skip navigation
Skip navigation

A simple, integrative assay to quantify nutritional quality of browses for herbivores

De Gabriel, Jane; Wallis, Ian; Moore, Ben; Foley, William

Description

Many regard the concentrations of nitrogen (N), tannins and plant cell wall constituents (fibre) as key indicators of food quality and habitat suitability for browsing herbivores; yet there is no method for measuring their combined effects. We have developed a simple in vitro assay for measuring the effects of tannins and fibre on N availability in browse. We determined the effects of tannins by measuring the polyethylene glycol (PEG)-binding capacity (PEG-BC) of Eucalyptus leaf samples,...[Show more]

dc.contributor.authorDe Gabriel, Jane
dc.contributor.authorWallis, Ian
dc.contributor.authorMoore, Ben
dc.contributor.authorFoley, William
dc.date.accessioned2015-12-10T22:25:46Z
dc.identifier.issn0029-8549
dc.identifier.urihttp://hdl.handle.net/1885/53630
dc.description.abstractMany regard the concentrations of nitrogen (N), tannins and plant cell wall constituents (fibre) as key indicators of food quality and habitat suitability for browsing herbivores; yet there is no method for measuring their combined effects. We have developed a simple in vitro assay for measuring the effects of tannins and fibre on N availability in browse. We determined the effects of tannins by measuring the polyethylene glycol (PEG)-binding capacity (PEG-BC) of Eucalyptus leaf samples, followed by a two-stage in vitro digestion with pepsin and cellulase to determine the digestibility of dry matter and N. There was a significant relationship between concentrations of digestible N and the PEG-BC of the leaves. Furthermore, adding PEG significantly improved the digestibility of N. Our results concur with in vivo observations from several mammalian species. This suggests that our method is effective for measuring the nutritional quality of browse and the benefits of adding PEG, providing some index of the detrimental effects of tannins. We further simplified the assay by removing the PEG step, allowing us to quickly analyse samples in bulk. Nevertheless, this simplified method is still not practical for analysing the many samples necessary to compare the nutritional values of different tracts of forest. We used near-infrared reflectance spectroscopy to produce calibration equations and predicted total and digestible N in 322 trees at eleven sites. Both within and between sites, we found a wide variation in concentrations of digestible N but a much lower variation in total N, with either no relationship or poor relationships between the two measures. This confirms the variability in the nutritional quality of eucalypt forests, which may explain the distribution and abundance of mammalian herbivores. Thus, our assay provides a useful tool for understanding how food resources influence herbivore populations at different scales.
dc.publisherSpringer
dc.sourceOecologia
dc.subjectKeywords: macrogol derivative; nitrogen; tannin derivative; bioassay; browsing; evergreen forest; habitat quality; herbivore; infrared spectroscopy; mammal; nutrient availability; nutritive value; spatial distribution; article; chemistry; Eucalyptus; metabolism; ne Eucalyptus; Folivory; Nitrogen availability; PEG; Tannins
dc.titleA simple, integrative assay to quantify nutritional quality of browses for herbivores
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume156
dc.date.issued2008
local.identifier.absfor060208 - Terrestrial Ecology
local.identifier.ariespublicationu9511635xPUB278
local.type.statusPublished Version
local.contributor.affiliationDe Gabriel, Jane, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationWallis, Ian, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationMoore, Ben, James Cook University
local.contributor.affiliationFoley, William, College of Medicine, Biology and Environment, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.startpage107
local.bibliographicCitation.lastpage116
local.identifier.doi10.1007/s00442-008-0960-y
dc.date.updated2015-12-09T09:27:26Z
local.identifier.scopusID2-s2.0-42149152046
local.identifier.thomsonID000255034300011
CollectionsANU Research Publications

Download

File Description SizeFormat Image
01_De Gabriel_A_simple,_integrative_assay_to_2008.pdf289.64 kBAdobe PDF    Request a copy


Items in Open Research are protected by copyright, with all rights reserved, unless otherwise indicated.

Updated:  19 May 2020/ Responsible Officer:  University Librarian/ Page Contact:  Library Systems & Web Coordinator