Abstract Detail

Bryological and Lichenological Section/ABLS

Weerakoon, Gothamie [1], Will-Wolf, Susan [2], Wijeyeratne, Chandrani [3], Wolseley, P.A. [4].

Corticolous lichens as indicators of undisturbed and disturbed vegetation types in the central mountains of Sri Lanka.

Tropical forests show a range of vegetation types corresponding to altitude and climate, but their natural extensions have been dramatically reduced by humans. This study investigates the lichen communities of three natural forests and four altered vegetation types in Sri Lanka and demonstrates the use of lichens as indicators of natural and disturbed vegetation types in tropical forests. Corticolous lichens were recorded in each vegetation type (six 100 m² sites/type) on 10 trees/site with DBH > 5 cm. Eight Phorophyte and nine microenvironmental characters were recorded. Lichen species were recorded from four ladder quadrats per tree trunk between 0.5 and 1.50 m height. Corticolous lichen composition was evaluated with nonmetric multidimensional scaling (NMS) ordination and correlations. Indicator species analysis (ISA) was performed on three different sets of site groups: the seven vegetation types, three groups of sites with different disturbance levels, and two groups of sites near to vs. far from an undisturbed site. We found distinct species composition for each vegetation type using NMS. Undisturbed sites had higher species richness of both trees and lichens than disturbed sites. Canopy cover, bark pH, distance to an undisturbed site, and years since disturbance were all correlated with the disturbance gradient. The study demonstrated significant relationships between lichen response and quality of the vegetation. From ISA analysis, thirty-four species were found to be strong indicators for a given vegetation type. Twenty species are strong indicators of undisturbed sites, while three species indicate moderately disturbed sites and five species indicate very disturbed sites. Six additional species are weaker indicators of disturbance level. Most indicators of disturbance level are visually distinct and parataxonomists could be trained to identify them in the field; these would be the most useful indicators for land managers. The environmental parameters correlated with lichen distribution can be used to identify sites of high conservation importance in fast depleting natural forests in south Asia. Our study showed similar differences due to disturbances compared with studies in temperate North America, with higher species richness per site in our study. Compared to studies in tropical Central and South America, our study showed higher species richness in vegetation types but similar patterns of response to disturbance and vegetation types. While the species are mostly different, 13 indicator genera (of 29 total) for our Sri Lanka sites are also reported from South American studies of sites with similar vegetation conditions.

1 - The Filed Museum, Science & Education, 1400, South Lake Shore Drive, Chicago, IL, 60605, USA
2 - University of Wisconsin, Department of Botany, 430 Lincoln Drive, Madison, WI, 53706, USA
3 - University of Sri Jayawardanapura, Botany, Sri Lanka
4 - The Natural History Museum, Botany, Cromwell Road, London, SW75BD, UK

Keywords:
lichens
indicators
Sri Lanka.

Presentation Type: Oral Paper:Papers for Sections
Session: 23
Location: River Fork/Grove
Date: Tuesday, July 29th, 2014
Time: 10:45 AM
Number: 23007
Abstract ID:173
Candidate for Awards:A. J. Sharp Award