Modelling the nutritional ecology of ungulate herbivores: evolution of body size and competitive interactions

Illius, A.W.; Gordon, Iain J.

doi:10.1007/bf00317422

Cited by 360 publications

(271 citation statements)

References 30 publications

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“…The allometric retention time for ruminants in general is described by the equation .695*Mb^.22 (days; Demment and van Soest, 1985;Illius and Gordon, 1992), and gives a retention time of 72.4 hours for a 1000 kg giraffe. Overall the conclusion must be drawn that Clauss et al's (2003A; estimates (13.7*Mb^.18; range 1.4-2.1 days) are the best available for retention time of ingesta in a giraffe.…”

Section: Discussionmentioning

confidence: 99%

The digestive morphophysiology of wild, free-living, giraffes

Mitchell

Roberts

Sittert

2015

Comparative Biochemistry and Physiology Part A: Molecular &

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We have measured rumen-complex (rumen, reticulum, omasum, abomasum) and intestine (small and large combined) mass in 32 wild giraffes of both sexes with body masses ranging from 289 -1441kg, and parotid gland mass, tongue length and mass, masseter and mandible mass in 9 other giraffes ranging in body mass from 181 to 1396kg. We have estimated metabolic and energy production rates, feed intake and home range size. Interspecific analysis of mature ruminants show that components of the digestive system increase linearly (Mb 1 ) or positively allometric (Mb >1 ) with body mass while variables associated with feed intake scale with metabolic rate (Mb .75 ). Conversely, in giraffes ontogenetic increases in rumen-complex mass were negatively allometric (Mb <1 ), and increases in intestine mass, parotid gland mass, masseter mass, and mandible mass were isometric (Mb 1 ). The relative masseter muscle mass (0.14% of Mb) and the relative parotid mass (0.03% of Mb) are smaller than in other ruminants. Increases in tongue length scale with head length 0.72 and Mb .32 and tongue mass with Mb .69 . Absolute mass of the gastrointestinal tract increased throughout growth but its relative mass declined from 20% to 15% of Mb. Rumen-complex fermentation provides ca43% of daily energy needs, large intestine fermentation 24% and 33% by digestion of soluble carbohydrates, proteins, and lipids. Dry matter intake (kg) was 2.4 % of body mass in juveniles and 1.6% in adults.Energy requirements increased from 35Mj/day to 190 Mj/day. Browse production rate sustains a core home range of 2.2-11.8 km 2 .

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Section: Discussionmentioning

confidence: 99%

The digestive morphophysiology of wild, free-living, giraffes

Mitchell

Roberts

Sittert

2015

Comparative Biochemistry and Physiology Part A: Molecular &

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“…In general, the passage data of this study support the concept that free-ranging browsing ruminants have faster passage rates than grazing ruminants. Illius and Gordon (1992) postulated that total GIT particle passage in ruminants was independent of feeding type, and was total GIT MRT particles (h) = 15.3 BM 0.251 .…”

Section: Discussionmentioning

confidence: 99%

Seasonal faecal excretion, gut fill, liquid and particle marker retention in mouflonOvis ammon musimon, and a comparison with roe deerCapreolus capreolus

et al. 2004

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Seasonal faecal excretion, gut fill, liquid and particle marker retention in mouflon ovis ammon musimon, and a comparison with roe deer capreolus capreolus Seasonal faecal excretion, gut fill, liquid and particle marker retention in mouflon ovis ammon musimon, and a comparison with roe deer capreolus capreolus AbstractFive mouflon (average body mass [BM] 33 kg) and two roe deer (average BM 20 kg) with rumen cannulas were kept in large enclosures under semi-natural conditions and were used for seasonal studies on gastrointestinal tract (GIT) indigestible fill and digesta passage kinetics. As the mouflon were not fully mature, both species had similar digesta volumes in the reticulorumen (RR; mouflon 5.5 ± 1.8% of BM; roe deer 5.4 ± 1.5% of BM); however, the mouflon had lower RR liquid flow rates (15.1 ± 4.3 ml h-1 kg-0.75) than the roe deer (19.2 ± 0.2 ml h-1 kg-0.75), and particle retention in the RR accounted for 68 ± 3% of total GIT retention in the mouflon versus 55 ± 6% in the roe deer. Annual average total GIT retention times for liquids and particles were longer in the mouflon (23.4 ± 0.9 h and 37.9 ± 4.0 h) than in the roe deer (18.4 ± 1.7 h and 22.4 ± 1.9 h). Similarly, annual average RR retention times for liquids and particles were longer in the mouflon (11.9 ± 0.9 h and 25.8 ± 3.3 h) than in the roe deer (8.1 ± 1.7 h and 12.5 ± 2.3 h). The factor of selective particle retention in the RR (retention of particles/retention of liquid) was 2.10 ± 0.09 in the mouflon versus 1.54 ± 0.01 in the roe deer. These observations are in accord with differences in digesta passage characteristics postulated between browsing and grazing ruminants. Total GIT indigestible fill was lower in the mouflon than in the roe deer (10.7 ± 2.1 g kg-1 and 13.3 ± 1.0 g kg-1). As the mouflon were not fully mature, both species had similar digesta volumes in the reticulorumen (RR; mouflon 5.5 ± 1.8% of BM; roe deer 5.4 ± 1.5% of BM); however, the mouflon had lower RR liquid flow rates (15.1 ± 4.3 ml h -1 kg -0.75 ) than the roe deer (19.2 ± 0.2 ml h -1 kg -0.75 ), and particle retention in the RR accounted for 68 ± 3% of total GIT retention in the mouflon versus 55 ± 6% in the roe deer. Annual average total GIT retention times for liquids and particles were longer in the mouflon (23.4 ± 0.9 h and 37.9 ± 4.0 h) than in the roe deer (18.4 ± 1.7 h and 22.4 ± 1.9 h). Similarly, annual average RR retention times for liquids and particles were longer in the mouflon (11.9 ± 0.9 h and 25.8 ± 3.3 h) than in the roe deer (8.1 ± 1.7 h and 12.5 ± 2.3 h). The factor of selective particle retention in the RR (retention of particles/retention of liquid) was 2.10 ± 0.09 in the mouflon versus 1.54 ± 0.01 in the roe deer. These observations are in accord with differences in digesta passage characteristics postulated between browsing and grazing ruminants. Total GIT indigestible fill was lower in the mouflon than in the roe deer (10.7 ± 2.1 g kg -1 and 13.3 ± 1.0 g kg -1 ).

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“…Many previous theoretical frameworks used to predict density do not take into account the characteristics of the resources, including particle size and availablity (Damuth 1987;Bohlin et al 1994;Enquist et al 1998;Carbone and Gittleman 2002;Haskell et al 2002;Jetz et al 2004). Most species within communities do not share common resources: consumers exploit different resources according to their ecological function (diet strategy and trophic level), body size, and phylogeny (Demment and Van Soest 1985;Vezina 1985;Shine 1991;Illius and Gordon 1992;Carbone et al 1999;Schmid et al 2000). Thus, in order to fully understand patterns in animal abundance, we need to understand the scaling of population density not only in relation to metabolic rate (resource need) but also in relation to the characteristics of the resources (particle size, distribution, and availability; Schmid et al 2000).…”

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confidence: 99%

The Scaling of Abundance in Consumers and Their Resources: Implications for the Energy Equivalence Rule

Carbone

Rowcliffe

Cowlishaw

et al. 2007

The American Naturalist

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The negative scaling of plant and animal abundance with body mass is one of the most fundamental relationships in ecology. However, theoretical approaches to explain this phenomenon make the unrealistic assumption that species share a homogeneous resource. Here we present a simple model linking mass and metabolism with density that includes the effects of consumer size on resource characteristics (particle size, density, and distribution). We predict patterns consistent with the energy equivalence rule (EER) under some scenarios. However, deviations from EER occur as a result of variation in resource distribution and productivity (e.g., due to the clumping of prey or variation in food particle size selection). We also predict that abundance scaling exponents change with the dimensionality of the foraging habitat. Our model predictions explain several inconsistencies in the observed scaling of vertebrate abundance among ecological and taxonomic groups and provide a broad framework for understanding variation in abundance.Keywords: population density, diet, allometry, energy equivalence rule.Understanding the relationship between the abundance of organisms and their resources is a key challenge in ecology (Brown 1995;Gaston and Blackburn 2000). One of the most widely used measures of abundance is population density (McNab 1963;Damuth 1981;Peters and Raelson 1984;Lindstedt et al. 1986;Silva et al. 2001 extensive empirical evidence for negative scaling of species population density in relation to body size (Damuth 1987;Duarte et al. 1987;Enquist et al. 1998). Many have also found support for invariance in population energy use across taxa within a trophic level (Damuth 1981(Damuth , 1998Enquist et al. 1998;Ackerman et al. 2004), a phenomenon known as the energy equivalence rule (EER; Nee et al. 1991). However, we still have a poor understanding of how these relationships emerge given the complexity of interactions among members of ecological communities. Many previous theoretical frameworks used to predict density do not take into account the characteristics of the resources, including particle size and availablity (Damuth 1987;Bohlin et al. 1994;Enquist et al. 1998;Carbone and Gittleman 2002;Haskell et al. 2002;Jetz et al. 2004). Most species within communities do not share common resources: consumers exploit different resources according to their ecological function (diet strategy and trophic level), body size, and phylogeny (Demment and Van Soest 1985;Vezina 1985;Shine 1991;Illius and Gordon 1992;Carbone et al. 1999;Schmid et al. 2000). Thus, in order to fully understand patterns in animal abundance, we need to understand the scaling of population density not only in relation to metabolic rate (resource need) but also in relation to the characteristics of the resources (particle size, distribution, and availability; Schmid et al. 2000).Here we develop a simple model of the scaling of animal abundance (measured as population density) in relation to the scaling of resource needs (metabolic rate) based on...

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Modelling the nutritional ecology of ungulate herbivores: evolution of body size and competitive interactions

Cited by 360 publications

References 30 publications

The digestive morphophysiology of wild, free-living, giraffes

The digestive morphophysiology of wild, free-living, giraffes

Seasonal faecal excretion, gut fill, liquid and particle marker retention in mouflonOvis ammon musimon, and a comparison with roe deerCapreolus capreolus

The Scaling of Abundance in Consumers and Their Resources: Implications for the Energy Equivalence Rule

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