Of goats and spines – a feeding experiment

Skarpe, Christina; Bergström, Roger; Danell, Kjell; Eriksson, Helena; Kunz, Camilla

doi:10.2989/10220119.2012.687075

Cited by 14 publications

(11 citation statements)

References 24 publications

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“…Our results concur with those presented by Pellew (1984c). Spines deter herbivory by preventing access to shoot biting and to leaf stripping thus forcing animals to pick small bites of leaves between the spines (Bergström, 1992;Gowda, 1996;Skarpe et al, 2012;Wilson and Kerley, 2003a). That bite mass is limited by spines and increases if they are removed is known from studies on different browsing animal species (Cooper and Owen-Smith, 1986;Skarpe et al, 2012).…”

Section: Bite Masssupporting

confidence: 89%

“…Although spines cannot stop browsers from feeding they reduce the bite mass and intake rates (Cooper and Owen-Smith, 1986;Dziba et al, 2003;Rooke et al, 2004). Spines act as deterrents to herbivory by limiting access to leaves or shoots directing browsing towards leaf picking (Bergström, 1992;Gowda, 1996;Skarpe et al, 2012;Wilson and Kerley, 2003a) and may restrict the time spent browsing on individual plants (Hartley et al, 1997;Milewski and Madden, 2006). Spineless woody plants often offer opportunities for browsers to strip many leaves in one bite or to take a large twig bite, as different to spiny plants (Searle and Shipley, 2008;Shipley, 2007).…”

Section: Introductionmentioning

confidence: 99%

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Giraffe browsing in response to plant traits

Mahenya¹,

Ndjamba

Mathisen³

et al. 2016

Acta Oecologica

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Intake rates by large herbivores are governed by among other things plant traits. We used Masai giraffe (Giraffa camelopardalis tippelskirchi Matschie) as study animals, testing whether they as very large browsers would follow the Jarman-Bell principle and maximize intake rate while tolerating low forage quality. We worked in Arusha National Park, Tanzania. We investigated how intake rate was determined by bite mass and bite rate, and show that bite mass and bite rate were determined by plant characteristics, governed by inherent plant traits, plant traits acquired from previous years' browsing, and season. We predicted that; (1) bite mass would be larger in trees without spines than with (2) bite mass would be larger in the wet season than in the dry, (3) bite rate would be higher in spinescent trees than in non-spinescent, (4) bite rate and/or bite mass would increase with previous years' browsing, (5) bite mass, bite rate or browsing time per tree would be highest for high trees with large, although still available canopies. Visual observations were used to collect data on tree attributes, number of bites taken and time of browsing. Sample size was 132 observed giraffe. We found that bite mass was larger in spineless than in spinescent trees and was larger in the wet season than in the dry. Bite rate, but not bite mass, increased with increasing browsing in previous years and was highest on two to three meter high trees and in spinescent 2 trees. Intake rate followed bite mass more than bite rate and was higher in spineless than in spinescent trees, higher in the wet season than in the dry, and tended to increase with tree height. Giraffe did not prioritize the highest intake rate, but browsed much on Acacias giving a high quality diet but a low intake rate.

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Section: Bite Masssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Giraffe browsing in response to plant traits

Mahenya¹,

Ndjamba

Mathisen³

et al. 2016

Acta Oecologica

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“…This combination of features suggests the spinelike leaf and bract tips of A. edenensis were more likely a specialization for predator deterrence than dispersal. Such spinelike leaf tips would probably have been of little obstacle to vertebrate herbivores (Palo and Robbins 1991;Belovsky and Schmitz 1994;Skarpe et al 2012) but are in the size range associated with a reduction in infestation by some chewing, sucking, and ovapositing insects (Moles et al 2013 and references therein).…”

Section: Plant-animal Interactionsmentioning

confidence: 98%

Plant-Arthropod Interactions inAcanthostrobus edenensis(Cupressaceae), a New Conifer from the Upper Cretaceous of Vancouver Island, British Columbia

Klymiuk

Stockey

Rothwell

2015

International Journal of Plant Sciences

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Editor: Michael T. Dunn Premise of research. A new, morphologically distinct, anatomically preserved conifer assignable to the basal Cupressaceae, which was subject to arthropod infestation during life, has been discovered within a marine carbonate concretion from the Coniacian (Late Cretaceous) Eden Main locality of Vancouver Island, British Columbia.Methods. Specimens were studied from anatomical sections prepared using the classic cellulose acetate peel technique.Pivotal results. This plant, described as Acanthostrobus edenensis gen. et sp. nov., has helically arranged needle leaves and terminal seed cones composed of numerous helically arranged bract/scale complexes dominated by the bract. Both vegetative leaves and bracts display exceptionally long, narrow tips that may have been involved in predator deterrence. The seed cone has diminutive ovuliferous scales with free distal margins; bract/scale complexes bear two to four small, secondarily inverted ovules. Cone tissues contain arthropod feeding galleries surrounded by necrotic tissue and closing tissue (wound periderm) that proliferated throughout the specimen.Conclusions. The new plant is clearly attributable to basal Cupressaceae (Cunninghamioideae, Taiwanioideae, and Athrotaxoideae). While it shares features with extinct Jurassic and Cretaceous Cupressaceae, it exhibits a novel combination of characters that distinguishes it from previously described genera. This discovery expands our understanding of basal cupressaceous diversity and provides insight into conifer-animal interactions during the Cretaceous.

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“…Spinescence has been the main focus of studies that have investigated how plants can physically impair mammalian herbivore foraging (Cooper & Owen-Smith 1986;Hanley et al 2007;Skarpe et al 2012;P erez-Harguindeguy et al 2013;Burns 2014). Surprisingly, the idea that the wholeplant structure, that is, the branching organization, might affect how and to what extent herbivores can forage a tree, and thus act as a defence trait, had until recently received little attention.…”

Section: Introductionmentioning

confidence: 99%

The architectural design of trees protects them against large herbivores

et al. 2017

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Summary Where large browsers are abundant, the survival of trees depends on their ability to deploy defences, either chemical or structural. Structural defences include the arrangement of dense and intricate architecture, termed ‘cage’ architecture. Previous studies showed that trees developing in herbivore‐rich environments tend to have more cage architecture but its precise effect on mammalian herbivores remains unknown. In this paper, we experimentally test how cage architecture affects the bite rate of goats, a generalist mammalian herbivore. We selected 11 palatable tree species with contrasting architectures. We described their caginess using an index combining spinescence and woodiness of their stems. Finally, we evaluated how the caginess of trees slows down herbivores when feeding on the inner leaves in tree crowns. We observed that the bite rate of goats on inner leaves of the cagiest trees was so severely reduced that they could not satisfy their daily nutritional requirements. We discuss how this could affect the preference of wild herbivores for less cagy trees, especially at the end of the dry season. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12876/suppinfo is available for this article.

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Of goats and spines – a feeding experiment

Abstract: We studied feeding behaviour by twig browsing goats in relation to two types of spines 35 of Acacia tortilis using experimental manipulation of the occurrence of spines.

Cited by 14 publications

References 24 publications

Giraffe browsing in response to plant traits

Giraffe browsing in response to plant traits

Plant-Arthropod Interactions inAcanthostrobus edenensis(Cupressaceae), a New Conifer from the Upper Cretaceous of Vancouver Island, British Columbia

The architectural design of trees protects them against large herbivores

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