Exploiting delayed transitions to sustain semiarid ecosystems after catastrophic shifts

Abstract

<jats:p>Semiarid ecosystems (including arid, semiarid and dry-subhumid ecosystems) span more than 40% of extant habitats and contain a similar percentage of the human population. Theoretical models and palaeoclimatic data predict a grim future, with rapid shifts towards a desert state, with accelerated diversity losses and ecological collapses. These shifts are a consequence of the special nonlinearities resulting from ecological facilitation. Here, we investigate a simple model of semiarid ecosystems identifying the so-called ghost, which appears after a catastrophic transition from a vegetated to a desert state once a critical rate of soil degradation is overcome. The ghost involves a slowdown of transients towards the desert state, making the ecosystem seem stable even though vegetation extinction is inevitable. We use this model to show how to exploit the ecological ghosts to avoid collapse. Doing so involves the restoration of small fractions of desert areas with vegetation capable of maintaining a stable community once the catastrophic shift condition has been achieved. This intervention method is successfully tested under the presence of demographic stochastic fluctuations.</jats:p>

Harnessing tipping points in complex ecological networks

“…systems described by a few first-order nonlinear differential equations or maps, a previous work investigated how small perturbations can be used to drive the system to a desired attractor (tipping point control) [49]. Quite recently, it has been demonstrated for semiarid ecosystems that the phenomenon of an ecological 'ghost', a long transient phase during which the system maintains its stability, may be exploited to delay or prevent the occurrence of a tipping point [50]. Our problem is significantly more challenging as we seek to investigate how tipping points in real-world complex and nonlinear dynamical networks in ecology, which are typically high-dimensional with phase-space dimension of © 2019 The Author(s) Published by the Royal Society.…”

Synthetic Biology for Terraformation Lessons from Mars, Earth, and the Microbiome

“…Figure adapted from Berdugo, et al 2017 [118]. In panel (e), it can be seen the same bistability in the vegetation than in the other traits as functionality (adapted from [129]).…”

“…Presumably, those changes would involve also a drastic change in soil microorganisms [125,126], which are the main biotic agents driving and connecting soil nutrients and stocks [127,128] and contribute importantly to enhance soil stability and water capacity. [100,111,129]. Functionality in semiard ecosystems depends on the aridity (c).…”

Synthetic soil crusts against green-desert transitions: a spatial model

“…What type of microscopic mechanisms could actually avoid green-desert transitions? In this paper, we are extending previous models of dryland dynamics [19,47] to predict the impact of bioengineering strategies on these fragile ecosystems. In this context, several bioremediation approaches have been developed in the last two decades to enhance and stabilize soil biocrusts (for an overview, see [26] and references therein).…”

“…Increasing aridity is pushing these ecosystems towards serious declines in microbial diversity, land degradation and loss of multifunctionality as desert states are approached [ 11 , 13 , 14 ]. Dedicated efforts have been addressing several avenues to both understanding how transitions can be anticipated by means of warning signals [ 15 – 17 ] and even prevented [ 11 , 18 , 19 ]. Catastrophic transitions i.e.…”