Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1890/1051-0761(2000)010[1133:CGOTAD]2.0.CO;2 |
Compensatory growth of the African dwarf shrub Indigofera spinosa following simulated herbivory | |
Oba, G; Mengistu, Z; Stenseth, NC | |
通讯作者 | Oba, G |
来源期刊 | ECOLOGICAL APPLICATIONS
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ISSN | 1051-0761 |
出版年 | 2000 |
卷号 | 10期号:4页码:1133-1146 |
英文摘要 | Use of long-term herbivory studies in understanding the effects of Livestock grazing on dwarf shrubs of arid zones of Africa is uncommon. Moreover, research has seldom focused on monitoring a 4-5 yr effect of herbivory at the level of individual plants. This study provided information on field-based experiments and simplified statistical modeling to test compensatory growth responses of individuals of the African dwarf shrub Indigofera spinosa in northwestern Kenya. From August 1986 to January 1990, we simulated livestock grazing during dry and wet seasons and over the full year, whereby plants were defoliated during both wet and dry seasons. Individuals of I. spinosa (n = 480 plants) were subjected to one of five clipping intensities: unclipped control (0%), light (30%), moderate (50%), severe (70%), and very severe (90%) clipping; and defoliated of regrowth (i.e., new biomass). Our findings showed that rainfall, clipping regimes, and seasons of treatment influenced the compensatory growth response. Rainfall more than residual biomass influenced regrowth, while plants with greater residual biomass produced more regrowth than those with less. Optimum residual biomass was achieved under the 30% clipping level, while least was maintained under the 90% level. We separated compensatory growth response into under- and overcompensation. We showed that overcompensation occurred under some conditions but not in others. The shrub displayed relative overcompensation with a compensatory ratio (CR) > 1.0 for three continuous years with light clipping regime during the wet season defoliations (WSD). In two of five years there was overcompensation with the dry season defoliations (DSD), but undercompensation (CR < 1.0) with full-year defoliations (FYD). On average, under the moderate, severe, and very severe clipping regimes the plants had undercompensation. Patterns’ of change of cumulative regrowth and its derivative, relative growth rates (RGR), provided different compensatory responses. RGR was more positive at lower cumulative regrowth but gradually declined and became negative when cumulative regrowth was maximum. The exception was in WSD where RGR remained positive for three years. DSD by far achieved greater cumulative regrowth than WSD and FYD. However, compared to the controls, FYD (except under light regime) exactly overcompensated for total "biomass budget" while WSD overcompensated under all clipping regimes except very severe. DSD under the light and moderate regimes overcompensated by +343.6% and by +202.7%, respectively. The study showed that I. spinosa combines tolerance with compensatory growth response to cope with a wide array of herbivory and seasons of use. The shrub may be grazed under light regime during the wet and dry seasons as opposed to the full-year grazing which is unsustainable. |
英文关键词 | arid zone compensatory growth compensatory ratio cumulative regrowth defoliation dwarf shrub land Indigofera spinosa Kenya relative growth rates residual biomass simulated herbivory |
类型 | Article |
语种 | 英语 |
国家 | Norway |
收录类别 | SCI-E |
WOS记录号 | WOS:000088496000015 |
WOS关键词 | NOMADIC PASTORAL ECOSYSTEM ; RESPONSES ; WATER ; OPTIMIZATION ; OVERCOMPENSATION ; NITROGEN ; ECOLOGY ; PLANTS ; DEFOLIATION ; SERENGETI |
WOS类目 | Ecology ; Environmental Sciences |
WOS研究方向 | Environmental Sciences & Ecology |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/138849 |
作者单位 | (1)Univ Oslo, Dept Biol, Div Zool, N-0316 Oslo, Norway;(2)Norwegian Water & Energy Directorate, Oslo, Norway;(3)Agr Univ Norway, NORAGRIC, N-1432 As Nlh, Norway |
推荐引用方式 GB/T 7714 | Oba, G,Mengistu, Z,Stenseth, NC. Compensatory growth of the African dwarf shrub Indigofera spinosa following simulated herbivory[J],2000,10(4):1133-1146. |
APA | Oba, G,Mengistu, Z,&Stenseth, NC.(2000).Compensatory growth of the African dwarf shrub Indigofera spinosa following simulated herbivory.ECOLOGICAL APPLICATIONS,10(4),1133-1146. |
MLA | Oba, G,et al."Compensatory growth of the African dwarf shrub Indigofera spinosa following simulated herbivory".ECOLOGICAL APPLICATIONS 10.4(2000):1133-1146. |
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