A network theoretic study of potential movement and spread of Lantana camara in Rajaji Tiger Reserve, India

TL;DR

This study models the spread of invasive Lantana Camara in Rajaji Tiger Reserve using GIS and complex network analysis, identifying key patches and network properties to inform management strategies.

Contribution

It introduces a novel integration of GIS, MaxEnt modeling, and complex network analysis to understand and identify critical regions for controlling lantana spread.

Findings

Key patches like dry river beds are crucial for lantana spread.

The lantana network exhibits small-world properties and community structure.

Management of identified hub patches can help contain invasion.

Abstract

Ecosystems are often under threat by invasive species which, through their invasion dynamics, create ecological networks to spread. We present preliminary results using a technique of GIS coupled with complex network analysis to model the movement and spread of Lantana Camara in Rajaji Tiger Reserve, India, where prey species are being affected because of habitat degradation due to Lantana invasion. Understanding spatio-temporal aspects of the spread mechanism are essential for better management in the region. The objective of the present study is to develop insight into some key characteristics of the regulatory mechanism for lantana spread inside RTR. Lantana mapping was carried out by field observations along multiple transects and plots and the data generated was used as input for MaxEnt modelling to identify land patches in the study area that are favourable for lantana growth. The patch information so obtained is integrated with a raster map generated by identifying different topographical features in the study area which are favourable for lantana growth. The integrated data is analysed with a complex network perspective, where relatively dense potential lantana distribution patches are considered as vertices, connected by relatively sparse lantana continuities, identified as edges. The network centrality analysis reveal key patches in the study area that play specialized roles in the spread of lantana in a large region. Hubs in the lantana network are primarily identified as dry seasonal river beds and their management is proposed as a vital strategy to contain lantana invasion. The lantana network is found to exhibit small-world architecture with a well formed community structure. We infer that the above properties of the lantana network have major contribution in regulating the rapid infestation and even spread of the plant through the entire region of study.