Biomass present before and after burning was measured in forest cleared for pasture in a cattle ranch (Fazenda Dimona) near Manaus, Amazonas, Brazil. Aboveground dry weight biomass loading averaged 265 t ha−1 (standard deviation (SD) = 110, n = 6 quadrats) at Fazenda Dimona, which corresponds to approximately 311 t ha−1 total dry weight biomass. A five‐category visual classification at 200 points showed highly variable burn quality. Postburn aboveground biomass loading was evaluated by cutting and weighing of 100 m2 quadrats and by line intersect sampling. Quadrats had a mean dry weight of 187 t ha−1 (SD = 69, n = 10), a 29.3% reduction from the preburn mean in the same clearing. Line intersect estimates in 1.65 km of transects indicated that 265 m3 ha−1 (approximately 164 t ha−1 of aboveground dry matter) survived burning. Using carbon contents measured for different biomass components (all ∼50% carbon) and assuming a carbon content of 74.8% for charcoal (from other studies near Manaus), the destructive measurements imply a 27.6% reduction of aboveground carbon pools. Charcoal composed 2.5% of the dry weight of the remains in the postburn destructive quadrats and 2.8% of the volume in the line intersect transects. Thus approximately 2.7% of the preburn aboveground carbon stock was converted to charcoal, substantially less than is generally assumed in global carbon models. The findings confirm high values for biomass in central Amazonia. High variability indicates the need for further studies in many localities and for making maximum use of less laborious indirect methods of biomass estimation. While indirect methods are essential for regional estimates of average biomass, only direct weighing such as that reported here can yield information on combustion efficiency and charcoal formation. Both high biomass and low percentage of charcoal formation suggest the significant potential contribution of forest burning to global climate changes from CO2 and trace gases.

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Dimorphandra wilsonii Rizzini is a rare species. Although cited as endemic to the Brazilian state of Minas Gerais, it has been recorded only for the municipalities of Paraopeba and Caetanópolis and therefore has not been extensively studied. This long-term, intensive survey, conducted from 2004 to 2012 in the central region of the state, was aimed at assessing its distribution, describing its habitat, and verifying its endemism, as well as assessing threats and determining its conservation status. Given the considerable size of the area to be studied and the difficulty of locating individuals of the species, we adopted popular participation as a complementary tool and we employed spatial distribution modeling. Communities were mobilized through the dissemination of print materials, and interviews were conducted. We visited 74 municipalities and addressed 900 people in search of this species. We found that D. wilsonii is endemic to the cerrado (savanna) and Atlantic Forest in the central region of Minas Gerais, occurring in 16 municipalities. Is not present in any fully protected conservation area, and its population (fewer than 250 individuals) is declining due to habitat destruction, caused mainly by agricultural/livestock and urban expansion, and its conservation status is "critically endangered". (Rizzini & Mattos Filho 1986). Although it has been considered rare and endangered since 1986, it was not until 1997 that it was added to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, where it was listed in the "endangered" category (Walter & Gillett 1998); it was later withdrawn because of the lack of information about the species. In 2000, it was added to the Red List of Endangered Species in the Flora of Minas Gerais, although it was listed there as "vulnerable" rather than "endangered" (Mendonça & Lins 2000). In 2003, we made an expedition to the reported sites of occurrence. We found only 13 adults, all of them in pastures of Urochloa spp. on three farms within the municipalities cited, a situation similar to that reported by Rizzini & Mattos Filho (1986). At that time, we conducted a review of the literature and found only the records of occurrence mentioned above (for Paraopeba and Caetanópolis). Therefore, later that year, the Botanical Garden of the Belo Horizonte Zoological and Botanical Foundation (hereafter referred only as the Botanical Garden), in cooperation with other institutions, initiated a survey of the remaining population (Fernandes et al. 2007), in order to define the distribution of D. wilsonii, characterize its environment, verify its endemism, identify threats to the species, and determine its conservation status. Material and methods Study areaThis study was conducted from January 2004 to October 2012. The study area comprises the central region of the state of Minas Gerais (Fig. 1). According to the Köppen-Geiger climate classification, the climate of the region is type Cwa (mesothermal), with dry winters and an average temperature in t...

Although there is a consensus among conservation biologists about the importance of genetic information, the assessment of extinction risk and conservation decision-making generally do not explicitly consider this type of data. Genetic data can be even more important in species where little other information is available. In this study, we investigated a poorly known legume tree, Dimorphandra exaltata , from the Brazilian Atlantic Forest, a hotspot for conservation. We coupled species distribution models and geospatial assessment based on herbarium records with population genetic analyses to evaluate its genetic status and extinction risk, and to suggest conservation measures. Dimorphandra exaltata shows low genetic diversity, inbreeding, and genetic evidence of decrease in population size, indicating that the species is genetically depleted. Geospatial assessment classified the species as Endangered. Species distribution models projected a decrease in range size in the near future (2050). The genetic status of the species suggests low adaptive potential, which compromises its chances of survival in the face of ongoing climatic change. Altogether, our coupled analyses show that the species is even more threatened than indicated by geospatial analyses alone. Thus, conservation measures that take into account genetic data and the impacts of climate change in the species should be implemented.

A survey of foliicolous fungi associated with Dimorphandra wilsonii and Dimorphandra mollis (Fabaceae) was conducted in the state of Minas Gerais, Brazil. Dimorphandra wilsonii is a tree species native to the Brazilian Cerrado that is listed as critically endangered. Fungi strictly depending on this plant species may be on the verge of co-extinction. Here, results of the pioneering description of this mycobiota are provided to contribute to the neglected field of microfungi conservation. The mycobiota of D. mollis, which is a common species with a broad geographical distribution that co-occurs with D. wilsonii, was examined simultaneously to exclude fungal species occurring on both species from further consideration for conservation because microfungi associated with D. wilsonii should not be regarded as under threat of co-extinction. Fourteen ascomycete fungal species were collected, identified, described and illustrated namely: Byssogene wilsoniae sp. nov., Geastrumia polystigmatis, Janetia dimorphandra-mollis sp. nov., Janetia wilsoniae sp. nov., Johansonia chapadiensis, Microcalliopsis dipterygis, Phillipsiella atra, Piricauda paraguayensis, Pseudocercospora dimorphandrae sp. nov., Pseudocercosporella dimorphandrae sp. nov., Ramichloridiopsis wilsoniae sp. and gen. nov., Stomiopeltis suttoniae, Trichomatomyces byrsonimae and Vesiculohyphomyces cerradensis. Three fungi were exclusively found on D. wilsonii and were regarded as potentially threatened of extinction: B. wilsoniae, J. wilsoniae and R. wilsoniae.