Abstract Detail

Ecology

Coyle, Jessica [1], Martin, Dante [1], Duan, Isabella [2], Liu, Eric [2], Miller, Jesse [2].

Environmental constraints on the geographic distribution of a lichen host and its putative parasite.

Lichens host a diverse microbiome, one component of which are endolichenic fungi. These ubiquitous non-lichen-forming fungi live intercellularly within the host lichen’s thallus, but for most, we know little about their ecology or geographic distributions. We studied ecological determinants of the geographic distribution of one such endolichenic fungus, Unguiculariopsis lettaui, which produces distinct ascomata on the common and broadly distributed lichen, Evernia prunastri. Published literature provided only two prior records of U. lettaui in the United States, yet initial observations by students in an undergraduate research course indicated a high prevalence in coastal Northern California. To map the distribution of U. lettaui in North America, we examined 272 Evernia prunastri collections in the University of California Jepson herbarium and E. prunastri collections from 1025 systematic plot surveys conducted by the U.S. Forest Inventory and Analysis program. We combined these maps with climate data and field surveys to evaluate which environmental factors limit the distribution of U. lettaui relative to its host, E. prunastri at different spatial scales. Except for two cases, U. lettaui was restricted to regions west of the Cascade and Sierra Nevada mountain ranges, ranging from southern Washington to central California. A structural equation model of field survey data in northern California indicated that the prevalence of U. lettaui infection is directly correlated with host abundance and limited both directly and indirectly by atmospheric moisture availability. Spatial models suggest that the geographic range of this endolichenic fungus is restricted relative to that of its host, but additional field observations from range-edge locations will be necessary to confirm this pattern. This research demonstrates a novel integration of existing botanical collections with large-scale public data to detect differential constraints on the geographic distribution of a lichen and its potential parasite.

1 - St. Mary's College of California, Biology, 1328 St. Mary's Rd, Moraga, CA, 94575, USA
2 - Stanford University, Biology

Keywords:
lichen
biogeography
Species Distribution Model
endolichenic fungi
Host-parasite
Collections
Undergraduate Research.

Presentation Type: Poster
Number: PEC021
Abstract ID:915
Candidate for Awards:None