# Localized states qualitatively change the response of ecosystems to varying conditions and local disturbances

## TL;DR

This study investigates how localized states influence the response of pattern-forming ecosystems, like dryland vegetation, to environmental changes and disturbances, revealing diverse outcomes including collapse, pattern formation, and increased biomass.

## Contribution

It demonstrates that localized states qualitatively alter ecosystem responses to oscillating precipitation and disturbances, highlighting their role in ecosystem resilience and transitions.

## Key findings

- Large amplitude precipitation oscillations can cause vegetation collapse or pattern stabilization.
- Local disturbances can lead to vegetation collapse or sustained biomass fluctuations.
- Localized states are key to understanding diverse ecosystem responses.

## Abstract

The response of dynamical systems to varying conditions and disturbances is a fundamental aspect of their analysis. In spatially extended systems, particularly in pattern-forming systems, there are many possible responses, including critical transitions, gradual transitions and locally confined responses. Here, we use the context of vegetation dynamics in drylands in order to study the response of pattern-forming ecosystems to oscillating precipitation and local disturbances. We focus on two precipitation ranges, a bistability range of bare soil with a patterned vegetation state, and a bistability range of uniform vegetation with a patterned vegetation state. In these ranges, there are many different stable states, which allow for both abrupt and gradual transitions between the system states to occur. We find that large amplitude oscillations of the precipitation rate can lead to a collapse of the vegetation in one range, while in the other range, they result in the convergence to a patterned state with a preferred wavelength. In addition, we show that a series of local disturbances results in the collapse of the vegetation in one range, while it drives the system toward fluctuations around a finite average biomass in the other range. Moreover, it is shown that under certain conditions, local disturbances can actually increase the overall vegetation density. These significant differences in the system response are attributed to the existence of localized states in one of the bistability ranges.