DOI: 10.1016/j.foreco.2013.04.013
Scopus记录号: 2-s2.0-84877835373
论文题名: Using a deterministic population model to evaluate population stability and the effects of fruit harvesting and livestock on baobab (Adansonia digitata L.) populations in five land-use types
作者: Venter S.M. ; Witkowski E.T.F.
刊名: Forest Ecology and Management
ISSN: 0378-1127
出版年: 2013
卷: 303 起始页码: 113
结束页码: 120
语种: 英语
英文关键词: Baboons
; Climate change
; Rainfall
; Recruitment
; Seedling protection
; Tolerance level
Scopus关键词: Baboons
; Environmental conditions
; Population structures
; Projection matrix model
; Recruitment
; Seedling protections
; Sustainable harvest
; Tolerance levels
; Climate change
; Fruits
; Land use
; Landforms
; Population statistics
; Rain
; Rural areas
; Seed
; Agriculture
; arid environment
; climate change
; fruit
; harvesting
; land use change
; livestock
; matrix
; nature reserve
; population decline
; population growth
; population modeling
; rainfall
; recruitment (population dynamics)
; sapling
; shrub
; tolerance
; Africa
英文摘要: The subsistence and commercial use of baobab (Adansonia digitata) fruit is important to many thousands of marginalized people in the arid tropics of Africa, yet sustainable harvest levels have not previously been studied. Size-class distributions of baobab populations tend to be stable, suggesting high tolerance to fruit harvesting. However, environmental conditions have changed substantially over the last 100. years. Increasing livestock numbers, land modification and climate change are new threats which may affect tolerance to fruit harvesting. To investigate this, a deterministic stage-based population projection matrix model was developed using (a) long term baobab monitoring data from 2 sites, (b) radiocarbon age calculations, (c) extensive field surveys of population structure and fruit (and seed) production, and (d) experimental field trials on seed banks and seedling and sapling survival in relation to the presence of livestock. Projected population growth (λ) was then evaluated for five land-use types (nature reserves, rocky outcrops, plains, fields, and villages) under three levels of livestock (none, moderate and high stocking rates). Response to fruit harvest intensity was tested for each scenario by decreasing seed availability by 10% from 100%. High livestock numbers resulted in baobab population declines, with λ<. 1 in all land-use types. Under moderate and zero livestock numbers, baobab populations in plains, rocky outcrops, villages and fields were able to tolerate between 33% and 90% fruit harvest rates. In nature reserves there was already high predation on immature fruit by baboons, another cause of population decline, with the model showing no tolerance whatsoever to fruit harvesting. These results show that fruit harvesting can be sustainable in production landscapes under moderate livestock levels. However the future is uncertain, as a predicted lowering of rainfall due to climate change is a further concern, with likely negative impacts on fruit yields and recruitment and consequently population projections. Thus active planting and protection of seedlings should take place to mitigate current and future negative impacts facing baobab populations. © 2013 Elsevier B.V.. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/66539
Appears in Collections: 影响、适应和脆弱性
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作者单位: Restoration and Conservation Biology Research Group, School of Animal Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg PO, Wits 2050, South Africa
Recommended Citation:
Venter S.M.,Witkowski E.T.F.. Using a deterministic population model to evaluate population stability and the effects of fruit harvesting and livestock on baobab (Adansonia digitata L.) populations in five land-use types[J]. Forest Ecology and Management,2013-01-01,303