Book of Abstracts (PDF) - International Mycological Association

IMC7 Friday August 16th Lectures
377 - Fungal biodiversity in Colombian Amazon forests:
species composition, ecology and function
A.E. Franco Molano 1* , C.A. Lopez Quintero 1 & T.
Boekhout 2
1
Dept. de Biologia, Universidad de Antioquia, Apartado
Aereo 1226, Medellin, Colombia. -
2
TROPENBOS,
Amsterdam, The Netherlands. - E-mail:
afranco@catios.udea.edu.co
This work constitutes an effort to establish the role of fungi
during regeneration processes of tropical lowland forests,
and was performed at the plots of Tropenbos Colombia in
Araracuara and Peña Roja, in central Caquetá of
Amazonian Colombia. The plots represent different
regeneration stages and primary forests and have been
investigated for a long time at Tropenbos Colombia. Our
project generated new data on the occurrence of macro-
and microfungi along a regeneration gradient in Colombian
Amazon lowland forests. Functional inferences suggest a
considerable role for the putative ectomycorrhizal fungi
and litter decomposing fungi in the nutrient cycling of
these forests. Decomposition of leaf litter can be relatively
fast, but seems to be influenced by the environmental
conditions. Shortly after trees are cut down, many woodinhabiting
fungi appear, which may occur as endophytes in
healthy trees. The formation of fruit bodies may be a result
of the stress imposed by the death of the hosts. After the
felled trees are burnt, soil borne microfungal populations
are dominated by heat resistant fungi. Many new taxa of
macro- and microfungi have been found, and await formal
description. New ideas about the role of microfungal
populations in nutrient cycling led to a new research
proposal to study the role of the microbial interface
connecting the roots of the trees with the environment in
secondary and primary forests.
378 - Diversity and complexity in Ascomycota from
Venezuela
T. Iturriaga 1* & D.W. Minter 2
1
Universidad Simón Bolívar, Dpto. Biología Organismos,
Aptdo. 89000, Sartenejas, Baruta, Edo. Miranda,
Venezuela. -
2
CAB International Mycological Inst.,
Bakeham Line, Egham, Surrey TW20 9TY, England, U.K. -
E-mail: titurri@usb.ve
Since the beginning of the 20th century and up to 1950,
there was a remarkable interest of the US towards Latin
America. The US Department of Agriculture sent UStrained
mycologists to conduct inventories on the natural
resources of several Latin American countries, and as a
result, neotropical mycological knowledge widened. That
was the period when Hans Sydow, and Chardon and Toro
published the results of their expeditions to Venezuela.
More recently, there has been an emphasis in fungal
systematics, an interest towards basic research, and more
participation of local mycologists, all of which have helped
improved knowledge on fungi in general. Programs such as
Flora Neotropica and Flora Amazonica Project, have
contributed toward an increased knowledge of fungi of the
neotropics. R. W. G. Dennis, has been a major contributor
towards neotropical fungal knowledge, specifically in
regards to ascomycetes. In his 'Fungus Flora of Venezuela
and Adjacent Countries', 1970, he treated approximately
1346 species of Ascomycetes. This talk will present
ascomycete collectors in Venezuela over the last 50 years,
as well as numbers of publications dealing with neotropical
ascomycetes in major mycological journals and congress
presentations. in this same area. Knowledge of the total
numbers of Ascomycetes for some neotropical areas will
be compared with other groups of fungi from the same
geographical regions.
379 - Ectomycorrhizal fungi associated with Dicymbe
(Caesalpiniaceae) in the Pakaraima Mountains of
Guyana
T.W. Henkel
Department of Biological Sciences, Humboldt State
University, Arcata, California 95521, U.S.A. - E-mail:
twh5@humboldt.edu
Mycological explorations in the Pakaraima Mountains of
western Guyana have unearthed unique forests dominated
by ectomycorrhizal (EM) tree species of the genus
Dicymbe Spruce ex Benth. (Caesalpiniaceae, tribe
Amherstieae). This remote region of tropical South
America is situated on the central Guiana Shield and is
characterized by highly oligotrophic soils. While EM
associations are still poorly known from South American
rain forests, the discovery of EM Dicymbe forests extends
the known range of EM associations substantially from
previously documented sites in the central Brazilian
Amazon and southern Venezuela. Species of Dicymbe
reach extreme levels of dominance (> 90% of stand basal
area) in a mosaic of primary forests in the Pakaraima
Mountains. Dicymbe stands are sharply demarcated from
surrounding mixed rain forests lacking in EM trees, and
harbor a rich EM mycota. Collecting efforts have currently
recorded > 150 species/morphospecies of EM fungi
occurring in close association with Dicymbe species. These
fungi are primarily basidiomycetes representing most of the
commonly accepted EM families, including Boletaceae,
Russulaceae, Amanitaceae, Cantharellaceae,
Cortinariaceae, and Paxillaceae. Putative EM ascomycetes
include Elaphomyces spp. and Pseudotulostoma volvata
O.K. Mill. & T.W. Henkel, a new taxon in the
Elaphomycetaceae. Ongoing systematic work on these
fungi will be discussed, with a focus on new and unusual
taxa.
Book of Abstracts 119