Sponsor
This research was supported by an Australian Research Council (grant #DP11010195) and National Science Foundation US (grants #0966472, #1738104, and #1832483).
Published In
Global Change Biology
Document Type
Post-Print
Publication Date
3-2020
Subjects
Climatic changes, Fire management
Abstract
Untangling the nuanced relationships between landscape, fire disturbance, human agency, and climate is key to understanding rapid population declines of fire‐sensitive plant species. Using multiple lines of evidence across temporal and spatial scales (vegetation survey, stand structure analysis, dendrochronology, and fire history reconstruction), we document landscape‐scale population collapse of the long‐lived, endemic Tasmanian conifer Athrotaxis selaginoides in remote montane catchments in southern Tasmania. We contextualized the findings of this field‐based study with a Tasmanian‐wide geospatial analysis of fire‐killed and unburned populations of the species. Population declines followed European colonization commencing in 1802 ad that disrupted Aboriginal landscape burning. Prior to European colonization, fire events were infrequent but frequency sharply increased afterwards. Dendrochronological analysis revealed that reconstructed fire years were associated with abnormally warm/dry conditions, with below‐average streamflow, and were strongly teleconnected to the Southern Annular Mode. The multiple fires that followed European colonization caused near total mortality of A. selaginoides and resulted in pronounced floristic, structural vegetation, and fuel load changes. Burned stands have very few regenerating A. selaginoides juveniles yet tree‐establishment reconstruction of fire‐killed adults exhibited persistent recruitment in the period prior to European colonization. Collectively, our findings indicate that this fire‐sensitive Gondwanan conifer was able to persist with burning by Aboriginal Tasmanians, despite episodic widespread forest fires. By contrast, European burning led to the restriction of A. selaginoides to prime topographic fire refugia. Increasingly, frequent fires caused by regional dry and warming trends and increased ignitions by humans and lightning are breaching fire refugia; hence, the survival Tasmanian Gondwanan species demands sustained and targeted fire management.
Rights
National Science Foundation, Grant/Award Numbers: 0966472, 1738104 and 1832483
The Federal awarding agency reserves a royalty-free, nonexclusive and irrevocable right to reproduce, publish, or otherwise use the work for Federal purposes, and to authorize others to do so.
This is the post-print version. The final version is available from the publisher:
https://doi.org/10.1111/gcb.15031
DOI
10.1111/gcb.15031
Persistent Identifier
https://archives.pdx.edu/ds/psu/33502
Citation Details
Holz, A, Wood, SW, Ward, C, Veblen, TT, Bowman, DMJS. [Post-print] Population collapse and retreat to fire refugia of the Tasmanian endemic conifer Athrotaxis selaginoides following the transition from Aboriginal to European fire management. Glob Change Biol. 2020; 26: 3108– 3121. https://doi.org/10.1111/gcb.15031
Figures
gcb15031-sup-0002-texts1.docx (14 kB)
GARerr models