Abstract Detail

Mycological Section

Roy, Bitty A. [1], Soukup, Hannah [2], Vandegrift, Roo [2], Thomas, Dan [3], Yombiyeni, Prudence [4].

Patterns of diversity of tropical forest saprotrophic fungi within the family Xylariaceae.

Tropical saprotrophic fungi are important for many reasons. First, most of the nutrient pool in tropical forests is rapidly cycled through dead leaves, twigs and logs, which are decomposed by fungi. Second, many other species, such as cavity nesting birds, depend on these fungi to help them make their homes. Third, to understand global carbon fluxes it is essential to understand the processes that affect the distribution and functioning of tropical decomposer fungi. Two common groups of wood decay fungi, the Polyporales sensu lato (“polypores”) and the Xylariaceae, are the primary focus here. As part of a pan-tropical study in September 2014 we surveyed wood litter for both fungal groups in the Smithsonian Center for Tropical Forest Science Forest Dynamic Plot at Rabi, Gabon. The plot is in the rich Guineo-Congolian rainforest, which has been very under collected for fungi. To sample we divided the 500 by 500 m plot into 9 equal sized subplots, then randomly chose four subplots for sampling. Within each subplot we used a log-scale sampling design to collect from 22 1m² quadrats for a total of 88 quadrats. We also collected throughout the forest and in other forests in Gabon to more completely capture the diversity present. One specific hypothesis concerned the genus Xylaria. Based on our earlier work in Ecuador and Taiwan, we predicted that Xylaria species would be water-limited for fruiting, with stromata occurring primarily near streams or on large woody debris, which holds water longer. Of the 88 1m2 Rabi quadrats, 64% had wood decomposing fungi fruiting from the family Xylariaceae, 16% had polypore fungi, and 8% had both groups. The 83 collections in the Xylariaceae were in the following genera: Annulohypoxylon (25.3%), Hypoxylon (22.9%), Jumillera (3.6%), Biscaugniauxia (12%), Kretzchmaria (12%), and Rosellinia (1.2%) but no Xylaria. An additional 26 fungal collections (31.3%) were sterile and are as yet undetermined. The mix of genera we collected at Rabi was similar to those we found in a similar sampling in Taiwan, except that Xylaria species were more common in Taiwan. However, compared to Ecuadorean cloud forest, which has abundant Xylaria, the lack of Xylaria in the Rabi plot in Gabon was striking. We did find Xylaria species in Gabon, but not in our Rabi quadrats, and only on large logs and near streams. These data are consistent with Xylaria often being water-limited for fruiting.

1 - University Of Oregon, Biology, 5289 CEEB, Eugene, OR, 97403-5289, USA
2 - University of Oregon, Biology, 5289 Ecology and Evolution, Eugene, OR, 97403-5289, USA
3 - University , Biology, 5289 Ecology and Evolution, Eugene, OR, 97403-5289, USA
4 - Institut de Recherche en Ecologie Tropicale (IRET), BP-13354 Gros Bouquet, Libreville, Gabon

Keywords:
Xylaria
Africa
decomposer.

Presentation Type: Oral Paper:Papers for Sections
Session: 29
Location: Salon 1/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 9:15 AM
Number: 29006
Abstract ID:1073
Candidate for Awards:None