Remotely sensed canopy height reveals three pantropical ecosystem states: reply

Xu, Chi; Staal, Arie; Hantson, Stijn; Holmgren, Milena; Nes, Egbert H. van; Scheffer, Marten

doi:10.1002/ecy.2077

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…Closed tree canopies are generally dominated by forest‐tree species (Ratnam et al., ), which, as opposed to those in savannas, have not evolved in conditions with regular fires (Keeley, Pausas, Rundel, Bond, & Bradstock, ). Apart from differences between ecosystem types, there are differences among continents in ecosystem structure (Xu et al., ) and in fire ecology (Lehmann et al., ). For example, fire frequency is relatively high in Africa (Giglio, Randerson, & van der Werf, ; Van Nes et al., ), although that may be counteracted by relatively low fire intensity (Dantas & Pausas, ) and relatively high recovery from disturbances in that continent (Schwalm et al., ).…”

Section: Discussionmentioning

confidence: 99%

Resilience of tropical tree cover: The roles of climate, fire, and herbivory

Staal

Nes

Hantson

et al. 2018

Global Change Biology

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Fires and herbivores shape tropical vegetation structure, but their effects on the stability of tree cover in different climates remain elusive. Here, we integrate empirical and theoretical approaches to determine the effects of climate on fire- and herbivore-driven forest-savanna shifts. We analyzed time series of remotely sensed tree cover and fire observations with estimates of herbivore pressure across the tropics to quantify the fire-tree cover and herbivore-tree cover feedbacks along climatic gradients. From these empirical results, we developed a spatially explicit, stochastic fire-vegetation model that accounts for herbivore pressure. We find emergent alternative stable states in tree cover with hysteresis across rainfall conditions. Whereas the herbivore-tree cover feedback can maintain low tree cover below 1,100 mm mean annual rainfall, the fire-tree cover feedback can maintain low tree cover at higher rainfall levels. Interestingly, the rainfall range where fire-driven alternative vegetation states can be found depends strongly on rainfall variability. Both higher seasonal and interannual variability in rainfall increase fire frequency, but only seasonality expands the distribution of fire-maintained savannas into wetter climates. The strength of the fire-tree cover feedback depends on the spatial configuration of tree cover: Landscapes with clustered low tree-cover areas are more susceptible to cross a tipping point of fire-driven forest loss than landscapes with scattered deforested patches. Our study shows how feedbacks involving fire, herbivores, and the spatial structure of tree cover explain the resilience of tree cover across climates.

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Section: Discussionmentioning

confidence: 99%

Resilience of tropical tree cover: The roles of climate, fire, and herbivory

Staal

Nes

Hantson

et al. 2018

Global Change Biology

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“…树木盖度(Hirota et al, 2011;Staver et al, 2011)和冠层高度(Xu et al, 2016(Xu et al, , 2018Hantson et al, 2017;Scheffer et al, 2018)的频度分布表现出显著的不连续多峰分布(multi-modal distribution)格局; 同时, 基于树木胸径、树皮厚度、比叶面积等植物性状 (Dantas et al, 2013, 2016)的地面观测结果也反映出一致的多峰分布格局, 这些分布的众数(峰值)分别图2 长江浅水湖群沉水植物生物量的不连续分布可能是浅水湖泊生态系统的多稳态证据。 (A)沉水植物生物量的频度分布表现出不连续的多峰分布(修改自王海军, 2007); (B)在水体总磷含量的梯度上沉水植物的生物量表现出不连续特征(修改自 Wang et al, 2014)。 Fig. 2 Discontinuous distribution of submerged plant biomass in the Yangtze shallow lakes as suggestive evidence of alternative stable states of shallow lake ecosystems.…”

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Alternative stable states and tipping points of ecosystems

Chi¹,

Wang²,

Liu³

et al. 2020

Biodiversity Science

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Many ecosystems may experience abrupt shifts at certain tipping points subject to gradual environmental changes or small perturbations. The theory of alternative stable states has been applied to explain a wide range of observed ecosystem tipping points. In recent years, alternative ecosystem states and tipping points have received increasing attention among both researchers and the public. Here, we reviewed the theoretical basis of alternative stable states, the approaches for detecting the existence of alternative stable states, and a set of "generic early warning indicators" for anticipating the transitions between alternative stable states. We also reviewed typical cases to demonstrate how the alternative stable states theory is linked to real-world ecosystems. and discuss the potential misuse and controversy with respect to the concept and applications of this theory. We expect to provide useful references to Chinese audiences in the fields of nonlinear ecosystem dynamics, ecosystem management and biodiversity conservation in a changing world.

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