{
  "id": 18301016,
  "title": "Human-caused ignitions and plant invasion drive fire-regime change in a dryland biodiversity hotspot",
  "url": "https://urgent.news/2026/11/05/human-caused-ignitions-and-plant-invasion-drive-fire-regime-change-in",
  "topic": "science",
  "section": "Science",
  "published": "2026-11-05T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.11.03.764038v1?rss=1"
  },
  "original_language": "en",
  "account": "Drylands, which encompass a large portion of the Earth's land area, are experiencing heightened vulnerability due to climate change, land-use alterations, and biological invasions. The Sonoran Desert, located in western North America and recognized as a biodiversity hotspot, has witnessed a shift from infrequent to frequent fire regimes as a result of these global changes. An analysis of over 73,000 wildland fire events has revealed the significant influence of human activities and plant invasions on fire dynamics in this desert ecosystem.\n\nHuman-induced ignitions were responsible for the overwhelming majority of fires recorded since the early 1990s, accounting for 95.5% of all documented incidents. These ignitions were primarily concentrated around human-modified areas such as roads, buildings, and other structures, particularly during the late spring season. In stark contrast, lightning-induced fires were infrequent within the Sonoran Desert itself and were more common in adjacent montane forests during the late summer months.\n\nSimilar to trends observed across the western United States, fires in the Sonoran Desert tended to be larger when they originated far from human infrastructure, where access for fire management is limited. Traditionally, fire management strategies in this region have focused on indirect approaches due to the challenging accessibility of remote fire ignition points.\n\nThe presence of annual and perennial herbaceous vegetation was found to enhance fire spread, even at relatively low cover values of just 5%. Conversely, bare ground acted as a barrier to fuel connectivity, thereby limiting the growth and progression of fires. Instead of adhering to a rigid threshold response, fire spread exhibited a linear relationship with the extent of herbaceous vegetation, indicating that modest increases in fine fuels can significantly alter fire behavior in this ecosystem that is historically characterized by sparse fuel sources.\n\nIn summary, this study highlights the crucial role of human ignitions in determining the location of fires, while the prevalence of herbaceous fuels dictates whether those fires will spread. The transformation of the fire regime in the Sonoran Desert, driven by these interacting factors, necessitates coordinated efforts to mitigate human-induced ignition sources, control invasive herbaceous plants, preserve bare-ground patches, and ensure rapid fire suppression. These findings not only shed light on the mechanisms underlying fire regime changes in dryland ecosystems but also offer a valuable framework for predicting and adapting to ecosystem transformations in response to ongoing global change.",
  "summary": "Dryland ecosystems cover much of Earths terrestrial surface and are increasingly affected by climate warming, land-use change, and biological invasion. The Sonoran Desert of western North America, a biodiversity hotspot that historically experienced infrequent fire, exemplifies how these global-change processes are driving ecosystem transformation through the emergence of novel disturbance…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}