Biology ETDs

Publication Date

Summer 7-15-2024

Abstract

Climate change related temperature increases, and precipitation shifts, along with an increase in fuel loads have rendered large areas of the Southwest more prone to high-severity fire for longer periods of time throughout each year. Fire adapted forests that experience high-severity, stand replacing fires are not consistently experiencing dominant tree species regeneration, and appear, in some cases, to be shifting into novel systems. We collected and analyzed up to 11 years of understory plant community data in ponderosa pine (Pinus ponderosa) forests in the Jemez Mountains, New Mexico, to address early forest regeneration after high and low severity fires. We hypothesized that because of a potential lack of tree regeneration after high severity fire the understory plant community would converge with montane grassland vegetation, which is moving up in elevation under climate change, rather than pine understory vegetation. Results indicated that a compositional shift occurred in the sites affected by high-severity fire generating a potentially novel, nonnative dominated herbaceous community. We found almost no tree seedlings in high-severity sites, while lower-severity sites maintained a more stable understory community and did have dominant tree species seedlings present nine years post-fire. Given that most tree seedling establishment occurs relatively quickly after fire, vegetation following high severity fire appears to be changing from woody to herbaceous plant communities. Continued data collection to better understand vegetation dynamics in high-severity sites will be necessary to determine if these areas will remain treeless in the future.

Document Type

Thesis

Degree Name

Biology

Level of Degree

Masters

Department Name

UNM Biology Department

First Committee Member (Chair)

Scott Collins

Second Committee Member

Robert Parmenter

Third Committee Member

Esteban Muldavin

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