Precipitation gradients drive high tree species turnover in the woodlands of eastern and southern Africa-猫眼课题宝

DOI：

10.1111/ecog.06720

发表时间：

2023-07

期刊：

Ecography

影响因子：

5.9

通讯作者：

中科院分区：

环境科学与生态学1区

文献类型：

作者：

Robert W. Davies;C. Ryan;R. Harrison;K. Dexter;A. Ahrends;M. te Beest;Lorena Benitez;T. Brade;J. Carreiras;D. Druce;A. Fayolle;M. Finckh;J. L. Godlee;Francisco M. Gonclaves;I. Grundy;T. Hoche;R. Holdo;S. Makungwa;I. McNicol;Penelope J. Mograbi;A. Muchawona;Aristidies Muhate;J. Muledi;R. Pritchard;R. Revermann;N. Ribeiro;Abel Siampale;A. Carla Staver;S. Syampungani;M. Williams;A. Swemmer;D. Edwards

稀树草原覆盖了地球表面的五分之一，拥有丰富的生物多样性，并为数亿人提供广泛的生态系统服务。热带湿润森林的树木群落组成随气候变化而变化，但在干扰驱动的稀树草原中，是否同样的过程结构群落仍然相对未知。我们研究了生物多样性是如何在非洲东部和南部林地的大环境和扰动梯度上结构的。我们使用来自非洲林地研究社会生态观测站（SEOSAW）网络的树木清单数据，覆盖了非洲东部和南部9个国家总计6780个地块的755公顷，来研究α、β和系统发育多样性在环境和干扰梯度中的变化。我们发现了强烈的气候丰富度模式，降水在决定这些稀树草原树木丰富度和高周转模式方面起着主要作用。降雨量大的热带稀树草原包含更多的树种，这表明低可用水量限制了物种的分布，从而形成了观测到的气候丰富度模式。火和草食对树木多样性的影响都很小，尽管它们在决定稀树草原的分布和结构方面起着重要作用。树种、属和科的高更替与美洲季节性干旱热带森林的更替相似，表明这是半干旱树木区系的一个特征。湿润样地的丰富度和系统发育多样性表明，大尺度生态模式适用于扰动驱动的稀树草原系统。高分类更替表明，如果我们要最大限度地保护独特的树木群落，就应该保护来自整个区域降雨梯度的稀树草原。

Savannas cover one‐fifth of the Earth's surface, harbour substantial biodiversity, and provide a broad range of ecosystem services to hundreds of millions of people. The community composition of trees in tropical moist forests varies with climate, but whether the same processes structure communities in disturbance‐driven savannas remains relatively unknown. We investigate how biodiversity is structured over large environmental and disturbance gradients in woodlands of eastern and southern Africa. We use tree inventory data from the Socio‐Ecological Observatory for Studying African Woodlands (SEOSAW) network, covering 755 ha in a total of 6780 plots across nine countries of eastern and southern Africa, to investigate how alpha, beta, and phylogenetic diversity varies across environmental and disturbance gradients. We find strong climate‐richness patterns, with precipitation playing a primary role in determining patterns of tree richness and high turnover across these savannas. Savannas with greater rainfall contain more tree species, suggesting that low water availability places distributional limits on species, creating the observed climate‐richness patterns. Both fire and herbivory have minimal effects on tree diversity, despite their role in determining savanna distribution and structure. High turnover of tree species, genera, and families is similar to turnover in seasonally dry tropical forests of the Americas, suggesting this is a feature of semiarid tree floras. The greater richness and phylogenetic diversity of wetter plots shows that broad‐scale ecological patterns apply to disturbance‐driven savanna systems. High taxonomic turnover suggests that savannas from across the regional rainfall gradient should be protected if we are to maximise the conservation of unique tree communities.

Precipitation gradients drive high tree species turnover in the woodlands of eastern and southern Africa

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