干旱区生态环境知识资源中心(Arid): Pans as possible pedological hotspots in an arid African savanna

Arid

DOI	10.1007/s11273-021-09798-5
	Pans as possible pedological hotspots in an arid African savanna
	Wallington, Caroline A.; Scholes, Mary C.
通讯作者	Wallington, CA (corresponding author), Univ Witwatersrand, Dept Anim Plants & Environm Sci, Johannesburg, South Africa.
来源期刊	WETLANDS ECOLOGY AND MANAGEMENT
ISSN	0923-4861
EISSN	1572-9834
出版年	2021
英文摘要	Vegetation dynamics in savannas are largely determined by water availability as well as soil nutrient dynamics. Species composition differs significantly from nutrient-rich soils to nutrient-poor soils, where the former is dominated by fine-leafed palatable woody species and the latter by broad-leafed and less palatable ones. Whilst this typically occurs at a landscape or catena scale, it is also interestingly observed at a localised and micro scale in areas such as wetlands and termite mounds. Wetlands are important edaphic contrasts in savannas and are paradoxically prevalent in the semi-arid to arid regions. In Southern Africa endorheic (inward draining) wetlands, known as pans, are particularly ubiquitous in arid regions but are not well studied compared to other wetland types. These wetlands were the focus of this study, which took place in the semi-arid savanna of the Limpopo plains, South Africa. The key research aims of this study were to determine how the pans differed from the surrounding terrestrial savanna landscape with respect to soil texture and chemistry, woody plant density and vegetation species composition. Top and sub soil samples were analysed to a depth of 30 and 60 cm and vegetation transects were carried out across three identified 'hydro-ecological' zones, i.e. the pan centre, the wooded wetland zone around the pan and representative terrestrial savanna habitat. In addition, drone aerial imagery was utilised to accurately determine woody species density and visually understand habitat changes. As hypothesised, the physiochemical properties of the soils differed along the study gradient from terrestrial to wetland, where in general the soil fertility, clay content and water holding capacity increased. The high clay content of the pans facilitates the surface pooling of rainwater and the possible maintenance of wetland conditions in these depressions which were found to be localised soil nutrient hotspots. The wooded wetland and terrestrial areas differed from each other in woody species composition where the terrestrial areas were largely dominated by broad leafed tree and shrub species and the wooded wetland areas had few to no broad-leafed species present but rather a dominance of fine-leafed Senegalia/Vachelia species. In addition, the Senegalia/Vachelia dominated habitat had a higher tree density than the surrounding bushveld, forming closed canopy patches in some areas. This change in vegetation and soil dynamics are important in savanna ecology as these habitats function quite differently from each other with respect to nutrient cycling, herbivore behaviour and biodiversity. It was concluded that these pans are nutrient-rich hotspots, likely playing an important ecological role in the savanna landscape. Furthermore, as they are likely to be key water sources and preferential forage sites, they could be the first to show signs of degradation and be useful indicators for land managers. These pans should be highlighted as sensitive habitats with regional conservation significance, which are deserving of adequate protection from surrounding threats such as mining.
英文关键词	Savanna Wetlands Pans Ecological hotspot Soil nutrient dynamics
类型	Article ; Early Access
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000642827400001
WOS类目	Environmental Sciences ; Water Resources
WOS研究方向	Environmental Sciences & Ecology ; Water Resources
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/352490
作者单位	[Wallington, Caroline A.; Scholes, Mary C.] Univ Witwatersrand, Dept Anim Plants & Environm Sci, Johannesburg, South Africa
推荐引用方式 GB/T 7714	Wallington, Caroline A.,Scholes, Mary C.. Pans as possible pedological hotspots in an arid African savanna[J],2021.
APA	Wallington, Caroline A.,&Scholes, Mary C..(2021).Pans as possible pedological hotspots in an arid African savanna.WETLANDS ECOLOGY AND MANAGEMENT.
MLA	Wallington, Caroline A.,et al."Pans as possible pedological hotspots in an arid African savanna".WETLANDS ECOLOGY AND MANAGEMENT (2021).