Past and ongoing shifts in Joshua tree distribution support future modeled range contraction.
Kenneth L Cole1, Kirsten Ironside, Jon Eischeid
1USGS, Colorado Plateau Research Station, P.O. Box 5614, Northern Arizona University, Flagstaff, Arizona 86011, USA. ken_cole@usgs.gov
Summary
Climate change threatens Joshua trees (Yucca brevifolia). Rising temperatures will eliminate most southern populations, while limited dispersal hinders natural expansion into new habitats.
Area of Science:
- Ecology
- Climate Change Biology
- Paleoecology
Background:
- The Joshua tree (Yucca brevifolia) is a keystone species in its ecosystem.
- Past climate warming events have impacted Joshua tree distribution.
- Megafaunal extinction may have limited Joshua tree's historical range expansion.
Purpose of the Study:
- To project the future distribution of the Joshua tree under climate change scenarios.
- To integrate paleoecological and modern ecological data for distribution modeling.
- To identify areas suitable for Joshua tree survival and potential assisted migration.
Main Methods:
- Geostatistical analysis of 20th-century climate data.
- Application of climate suitability models to future climate projections from multiple General Circulation Models (GCMs).
- Integration of paleoecological data on past climate change responses.
Main Results:
- All models project significant range contraction, with elimination in southern areas due to rising temperatures.
- Limited populations are predicted to remain sustainable within the current range.
- Potential for expansion into new areas exists, but natural dispersal is likely insufficient.
Conclusions:
- Climate change poses a severe threat to Joshua tree survival.
- Assisted migration may be necessary to preserve the species.
- Integrating diverse data sources is crucial for understanding and predicting species' responses to climate change.
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