# Signatures of human impact on self-organized vegetation in the Horn of Africa

## TL;DR

This study uses remote sensing to analyze how human activities, especially road development, have altered vegetation band patterns in the Horn of Africa's drylands, revealing impacts on ecosystem dynamics and vegetation structure.

## Contribution

It provides the first detailed remote sensing analysis linking human activity to changes in vegetation band widths and composition in the Horn of Africa.

## Key findings

- Vegetation band widths have increased with human activity.
- Altered colonization and mortality rates at band edges.
- Human-induced shifts in plant species composition observed.

## Abstract

In many dryland environments, vegetation self-organizes into bands that can be clearly identified in remotely-sensed imagery. The status of individual bands can be tracked over time, allowing for a detailed remote analysis of how human populations affect the vital balance of dryland ecosystems. In this study, we characterize vegetation change in areas of the Horn of Africa where imagery taken in the early 1950s is available. We find that substantial change is associated with steep increases in human activity, which we infer primarily through the extent of road and dirt track development. A seemingly paradoxical signature of human impact appears as an increase in the widths of the vegetation bands, which effectively increases the extent of vegetation cover in many areas. We show that this widening occurs due to altered rates of vegetation colonization and mortality at the edges of the bands, and conjecture that such changes are driven by human-induced shifts in plant species composition. Our findings suggest signatures of human impact that may aid in identifying and monitoring vulnerable drylands in the Horn of Africa.