Recent declines in aspen populations have occurred in the western U.S., especially along drought-sensitive margins of its range or where fire exclusion and herbivory have promoted community transition.
Examining mechanisms that influence aspen persistence can offer conservation insights, especially where populations are vulnerable to changing climate or disturbance. USGS researchers sampled isolated aspen forests in the arid Great Basin to determine if they are more likely to be fire-dependent and seral, or fire-independent and stable. They also looked at whether ungulate browsing inhibits aspen stability and how aspen reproduction over time was correlated with climate. Researchers found that most aspen stands were fire-independent and stable, and generally exhibited regeneration rates adequate for self-replacement, with exceptions mostly occurring in heavily browsed stands. Complex regeneration dynamics of these self-sustaining aspen stands, including sensitivity to climate variability, suggest they may serve as harbingers of ecological change in the arid Great Basin and for other aspen forests near arid range margins.
Shinneman, D.J., McIlroy, S.K., 2019, Climate and disturbance influence self-sustaining stand dynamics of aspen (Populus tremuloides) near its range margin: Ecological Applications, https://doi.org/10.1002/eap.1948