Plant clonal morphologies and spatial patterns as self-organized responses to resource-limited environments

TL;DR

This study models plant clonal morphologies in resource-limited environments as self-organized structures resulting from facilitation and competition among ramets, successfully reproducing observed patch patterns and inter-patch distances.

Contribution

It introduces a simple integro-differential model that captures the self-organization of plant patches based on non-local interactions among clonal ramets.

Findings

Model reproduces patch patterns observed in the Andean altiplano.

Predicted inter-patch distances match real measurements.

Model can be used to forecast vegetation responses to environmental changes.

Abstract

We propose here to interpret and model peculiar plant morphologies (cushions, tussocks) observed in the Andean altiplano as localized structures. Such structures resulting in a patchy, aperiodic aspect of the vegetation cover are hypothesized to self-organize thanks to the interplay between facilitation and competition processes occurring at the scale of basic plant components biologically referred to as 'ramets'. (Ramets are often of clonal origin.) To verify this interpretation, we applied a simple, fairly generic model (one integro-differential equation) emphasizing via Gaussian kernels non-local facilitative and competitive feedbacks of the vegetation biomass density on its own dynamics. We show that under realistic assumptions and parameter values relating to ramet scale, the model can reproduce some macroscopic features of the observed systems of patches and predict values for the inter-patch distance that match the distances encountered in the reference area (Sajama National Park in Bolivia). Prediction of the model can be confronted in the future to data on vegetation patterns along environmental gradients as to anticipate the possible effect of global change on those vegetation systems experiencing constraining environmental conditions.