Abstract Detail

Mycological Section

Huang, Yu-Ling [1], Devan, MM Nandi [2], U'Ren, Jana M. [1], Furr, Susan H. [1], Arnold, A. Elizabeth [1].

Pervasive effects of wildfire on foliar endophyte communities in montane forest trees.

Trees in fire-adapted ecosystems form intimate symbioses with endophytic fungi that inhabit their healthy leaves. How these symbionts respond to major wildfires has not been studied previously. The goal of this study was to examine effects of severe, crown-killing wildfires on endophyte communities in ecologically important genera of forest trees, with a focus on traditionally fire-dominated montane ecosystems in the southwestern USA. Specifically, we used culture-based method to evaluate the abundance, diversity, and composition of endophytes in healthy foliage of Juniperus deppeana (Cupressaceae) and Quercus spp (Fagaceae) collected contemporaneously from areas affected by recent, severe wildfire (i.e., within and bordering areas burned in major fire events within the past 1-18 y) and paired areas not affected by recent fire (i.e., in proximate areas in which severe fires have not occurred within >50-100 y) across four mountain ranges in central and southern Arizona. We tested the broad hypotheses that (1) recent, severe fires would markedly alter the abundance, diversity, and composition of endophyte communities relative to those in proximate, unburned trees; and (2) such differences would decrease as time since fire increases. Samples were grouped into three fire age classes (≤ 6 y, 7-18 y, and > 50 y since the major wildfire) according to the fire history. Analyses of >1100 endophyte isolates revealed pervasive effects of severe fires on endophyte communities: isolation frequency, diversity, community structure and taxonomic composition differed as a function of fire age class. Observed differences did not correspond to intrinsic differences among geographic locations, herbivory or pathogen damage, or leaf chemistry. Although communities differed significantly between host taxa, responses to fire were similar in endophytes of each host in these traditionally fire-dominated ecosystems. Several potentially fire-tolerant taxa (eg. Pezizomycetes) were prevalent in fire-affected trees but rare or absent in trees not affected by recent fire, whereas other major groups (e.g., Leotiomycetes) were absent in most recent fire-affected trees. Fungal endophytes present in trees after severe fire represented subsets of the available mycoflora that appear to circulate at a regional scale among these historically fire-affected forests. Together these findings contribute to an emerging perspective on the responses of diverse communities to severe fire, and highlight the importance of considering fire history when estimating endophyte diversity and community structure for particular biomes.

1 - University of Arizona, School of Plant Sciences, 1140 E. South Campus Drive, Forbes 303, Tucson, AZ, 85721, USA
2 - University of Arizona, Department of Ecology and Evolutionary Biology, 1041 E. Lowell, Tucson, AZ, 85721, USA

Keywords:
Ascomycota
diversity
Dothideomycetes
Eurotiomycetes
fire history
forest management
fungal endophytes
Leotiomycetes
Pezizomycetes
phenology
Sordariomycetes
symbiosis.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PMY014
Abstract ID:783
Candidate for Awards:MSA Best Poster Presentation Award by a Graduate Student