Forest Resources and Wildlife Management Publications

Permanent URI for this collection

http://196.220.97.103:4000/handle/123456789/167
Forest Resources and Wildlife Management Publications

Browse

Browsing Forest Resources and Wildlife Management Publications by Author "Ndlovu, L.R."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Effect of leaf size, thorn density and leaf accessibility on instantaneous intake rates of five woody species browsed by Matebele goats (Capra hircus L) in a semi-arid savanna, Zimbabwe
    (Elsevier, 2010) Sebata, A.; Ndlovu, L.R.
    Browse instantaneous intake rate (IIR) is a product of bite size and bite rate which are constrained by plant morphology. We studied the effects of leaf size, thorn density and leaf accessibility on the IIRs of five browse species in semi-arid savanna over three leaf phenophases using cafeteria-style trials. Bite size was influenced by leaf size and bite rate by leaf accessibility, while thorn density had an impact on both bite size and bite rate. The lowest IIRs were recorded on the small leafed Acacia tortilis which also had the highest thorn density. Dichrostachys cinerea had the highest IIRs due to the large bite sizes. Although Terminalia prunioides and Commiphora pyracanthoides had small leaves, their arrangements in clusters allowed for higher IIRs, which were comparable to those of the large leafed D. cinerea. Instantaneous intake rate showed no clear trend in relation to leaf phenophase, although at early leaf the goats cropped smaller bites because of the small size of the newly sprouting leaves. We conclude that leaf size influenced IIRs through bite size, leaf accessibility through bite rate and thorn density through both bite size and bite rate.
  • No Thumbnail Available
    Item
    Within-plant variation in defences in response to simulated herbivory in a semi-arid southern African savannah
    (John Wiley & Sons Ltd, 2015) Sebata, A.; Ndlovu, L.R.
    Within-plant spatial variation in herbivore pressure can induce localized antiherbivory defence responses. We tested this hypothesis by studying branch-specific responses of Acacia robusta, Dichrostachys cinerea and Ziziphus mucronata to simulated mammalian herbivory. Herbivory was simulated by clipping the terminal shoots (3 cm from tip) of tree branchlets, allowing them one year of regrowth and then comparing their spine length and density and condensed tannins with those of adjacent unclipped branchlets. Condensed tannins concentrations were higher in clipped branchlets than in unclipped branchlets in all three woody species (P < 0.05). Spine length was higher in clipped branchlets than in unclipped branchlets in A. robusta (P < 0.05) but was similar in both D. cinerea and Z. mucronata (P > 0.05). Spine density was double in clipped branchlets as compared to the unclipped branchlets in Z. mucronata (P < 0.05) but was similar in both A. robusta and D. cinerea (P > 0.05). We found evidence of within-plant variation in condensed tannins concentration and spine length and density in response to simulated herbivory in the three woody species.