1,721,116 research outputs found
An analytical model to relate the vertical root distribution to climate and soil properties
No full textWe propose an analytical model to relate the vertical distribution of plant roots in water controlled ecosystems to the local climatic and pedologic conditions. We find that the shape of the root profile is determined by the distribution of the incoming rainfall pulses, and that the rooting systems are deeper where the soils are coarse-textured and the evaporative demand slightly exceeds precipitation. Citation: Laio, F., P. D'Odorico, and L. Ridolfi (2006), An analytical model to relate the vertical root distribution to climate and soil propertie
A probabilistic analysis of fire-induced tree-grass coexistence in savannas
No full textFires play an important role in determining the composition and structure of vegetation in semiarid ecosystems. The study of the interactions between fire and vegetation requires a stochastic approach because of the random and unpredictable nature of fire occurrences. To this end, this article develops a minimalist probabilistic framework to investigate the impact of intermittent fire occurrences on the temporal dynamics of vegetation. This framework is used to analyze the emergence of statistically stable conditions favorable to tree- grass coexistence in savannas. It is found that these conditions can be induced and stabilized by the stochastic fire regime. A decrease in fire frequency leads to bush encroachment, while more frequent and intense fires favor savanna- to- grassland conversions. The positive feedback between fires and vegetation can convert states of tree- grass coexistence in semiarid savannas into bistable conditions, with both woodland and grassland as possible, though mutually exclusive, stable states of the syste
Transitions between stable states in the dynamics of soil development
Full text linkThe dynamics of soil development and erosion is studied through a stochastic soil mass balance in which the
soil production by bedrock weathering is expressed as
a state-dependent deterministic function, while the erosion by landslides is modeled as a marked Poisson process. For a range of values of the parameters the dynamics is bistable and the noise drives the transitions
from a state to another through a potential barrier. The
rates of such a transition are analytically estimated and
their dependence on the system parameters is briefly
discussed
Noise-induced stability in dryland plant ecosystems
No full textDryland plant ecosystems tend to exhibit bistable dynamics with two preferential configurations of bare and vegetated soils. Climate fluctuations are usually believed to act as a source of disturbance on these ecosystems and to reduce their stability and resilience. In contrast, this work shows that random interannual fluctuations of precipitation may lead to the emergence of an intermediate statistically stable condition between the two stable states of the deterministic dynamics of vegetation. As a result, there is an enhancement of ecosystem resilience and a decrease in the likelihood of catastrophic shifts to the desert state
Problems and progress in land, water and resources rights at the beginning of the third millennium
No full textEffect of vegetation-water table feedbacks on the stability and resilience of plant ecosystems
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