Marcela E. da S. CáceresDoctoral student
At Mycology Dept. until 01/2007
Abteilung Mykologie, Lehrstuhl für Pflanzensystematik – Universität Bayreuth, Universitätsstraße 30 - NW I, D-95440 Bayreuth
- PhD Research Project: "Corticolous Lichens of Northeastern Brasil: Atlantic rainforest and Caatinga – Inventory and Biodiversity, Ecology of Lichen Species and Lichen Communities"
- Foliicolous Lichens of Northeastern Brazil - Biodiversity and Biogeography
- Descriptive Data of the Genera Polycoccum, Stigmidium and Pyrenidium in the LIAS Database
Consult DALI Database
Corticolous Lichens of Northeastern BrasilBrazil is the fifth largest country in the world and comprises five main ecoregions: the Amazon, Pantanal, Cerrado, Caatinga, and Mata Atlântica. Northeastern Brazil comprises the States of Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe and Bahia. Three vegetation zones can be recognized in this region:  the coastal Atlantic rainforest (Mata Atlântica), along the coast and extending from Rio Grande do Norte to Rio Grande do Sul, in its northern part characterized as perennial forest with pronounced dry season;  the Caatinga, a very dry thornbush vegetation, and  the montane Atlantic rainforest, the so-called 'Brejos de Altitude', which consist of rainforest remnants isolated from the coastal vegetation and located amidst the Caatinga in areas of higher elevation (800–900 m).
Unfortunately, more than 95% of the original vegetation cover in northeastern Brazil has been destroyed or alterated by human activities such as agriculture (sugar cane), logging, and extension of large cities like Recife (Pernambuco) and Salvador (Bahia). One of the consequences of deforestation is the increasing drought, which further affects the already reduced and overstressed rainforests remnants.
Lichens are expected to develop a high diversity in this mixture of dry and humid vegetation, with an estimated number of 1000 species, but thus far no floristic treatment of northeastern Brazil is available. Current knowledge of Brazilian lichens is mostly based on work performed in the southern region; yet, northeastern lichenology has tradition by the late mycologist Batista, who studied lichenized microfungi in the sixties. His work was briefly continued by his students Cavalcante and Xavier Filho. Later, Xavier Filho became interested in applied lichen biochemistry, a field that has been successfully expanded by Eugenia Pereira. The first detailed floristic study of foliicolous lichens, including a revision of Batista's material, was undegone by Cáceres in 1999, coming up with more than 200 species. Following this approach, a survey of corticolous microlichens started in 2000 as a Ph. D. project at the University of Bayreuth, thus far revealing more that 100 new records for the area.
Foliicolous Lichens of Northeastern BrazilA floristic survey of foliicolous lichens in the Mata Atlântica of Pernambuco (Brazil), in the frame of a M.Sc. at the Federal University of Pernambuco, revealed a total of 191 species, comprising 47 genera, 18 families and 11 orders. Sixty-one foliicolous lichens and six lichenicolous fungi were reported for the first time for the state. For the Atlantic rainforest as a whole, 45 foliicolous lichens and six lichenicolous fungi represent new records, while 19 foliicolous lichens and three lichenicolous fungi are new records for Brazil, increasing the acknowledged diversity for the country to 354 foliicolous lichens and 39 lichenicolous fungi. Five species were described as new.
Most of the species have a wide distribution, being pantropical or widely neotropical. Apart from the reduced diversity found in the northern part of the Atlantic rainforest, explained by the drier climate, species composition is very similar to that of other neotropical regions such as Costa Rica, Amazonia and the southern Mata Atlântica. Comparison between four representative localities of the Atlantic rainforest in Pernambuco indicates that local diversity of foliicolous lichens is strongly affected by the degree of deforestation. Degradation of the vegetation also explains the absence of well-defined species communities, as certain communities disappear with increasing drought. This study also suggests that isolated forest remnants cannot conserve the biodiversity present within the original forest cover, but several remnants have to be connected by biological corridors to serve that purpose.