There are a number of controversies surrounding both biomass estimation and carbon balance in tropical forests. Here we use long-term (from 1978 through 2000) data from five 0.5-ha permanent sample plots (PSPs) within a large tract of relatively undisturbed Atlantic moist forest in southeastern Brazil to quantify the biomass increment (DeltaM(I)), and change in total stand biomass (DeltaM(stand)), from mortality, recruitment, and growth data for trees >/=10 cm diameter at breast height (DBH). Despite receiving an average of only 1,200 mm annual precipitation, total forests biomass (334.5+/-11.3 Mg ha(-1)) was comparable to moist tropical forests with much greater precipitation. Over this relatively long-term study, forest biomass experienced rapid declines associated with El Niño events, followed by gradual biomass accumulation. Over short time intervals that overlook extreme events, these dynamics can be misinterpreted as net biomass accumulation. However for the 22 years of this study, there was a small reduction in forest biomass, averaging -1.2 Mg ha(-1) year(-1) (+/-3.1). Strong climatic disturbances can severely reduce forest biomass, and if the frequency and intensity of these events increases beyond historical averages, these changing disturbance regimes have the capacity to significantly reduce forest biomass, resulting in a net source of carbon to the atmosphere.

RESUMOMedidas precisas de volume de madeira são ferramentas importantes no planejamento do uso do recurso florestal. Neste estudo, foram investigados modelos volumétricos para a Floresta Nacional do Tapirapé-Aquirí, na Serra dos Carajás (PA), baseados numa cubagem rigorosa de 55 árvores para obter o diâmetro, altura comercial do fuste e volume sólido. Um total de 8 modelos de dupla entrada e 4 de simples entrada foram testados para o diâmetro mínimo de 14 cm. Para seleção do melhor modelo foram usadas as estatísticas do coeficiente de determinação, erro padrão da estimativa e distribuição dos resíduos. Entre os modelos de simples entrada o modelo logarítmico de Husch se ajustou melhor aos dados (R 2 = 0,9105) e entre os de dupla entrada o logarítmico de Schumacher & Hall se ajustou melhor (R 2 = 0,9942). O uso do modelo da Flona de Tapajós ou o uso do modelo de volume cilíndrico com fator de forma 0,7 subestimam a volumetria na Flona do Tapirapé. Isso enfatiza a importância de modelos volumétricos locais para melhorar a precisão da estimativa de madeira. PALAVRAS-CHAVEEquações de volume, modelos logarítmicos, manejo florestal, floresta tropical, Carajás. Volumetric models for Tapirapé-Aquirí

No abstract

The extinction of large frugivores has consequences for the recruitment of large-seeded plants with potential lasting effects on carbon storage in tropical rainforests. However, previous studies relating frugivore defaunation to changes in carbon storage ignore potential compensation by redundant frugivores and the effects of seed predators on plant recruitment. Based on empirical data of the recruitment success of a large-seeded hardwood tree species (Cryptocarya mandioccana, Lauraceae) across a defaunation gradient of seed dispersers and predators, we show that defaunation increases both seed dispersal limitation and seed predation. Depending on the level of seed predator loss, plant recruitment is reduced by 70.7–94.9% as a result of the loss of seed dispersers. The loss of large seed predators increases the net seed mortality by 7–30% due to the increased abundance of small granivorous rodents. The loss of large seed dispersers can be buffered by the compensatory effects of smaller frugivores in seed removal, but it is not sufficient to prevent a decrease in plant recruitment. We show that the conservation of both seed predators and dispersers is necessary for the recruitment of large-seeded plants. Since these plants contribute substantially to carbon stocks, defaunation can jeopardize the maintenance of tropical forest carbon storage.

Damage caused by capybaras in agroecossystems in Brazil has been frequently observed. The objective of this study was to describe and quantify the actual damage caused by capybaras in a corn field, aiming to get basic information on how, how much, and where these damage occur. Systematic sampling indicated that 26% of the planted area were damaged by capybaras, and the highest percentage of damage occurred on the border of the corn field (t=4.5698, p=0.0001). Damage in areas adjacent to a forest fragment was significantly higher (t=13.6198, p=0.0001), suggesting that the strategy of area utilization for feeding was related to the proximity of the resources "forest" and "water". Avoiding corn plantation in areas adjacent to forest fragments used by capybaras and, when possible, controlling capybara population may lead to a reduction of damage occurrence in agroecossystems.

Abstract. Soils of tropical forests are important to the global budgets of greenhouse gases. The Brazilian Atlantic Forest is the second largest tropical moist forest area of South America, after the vast Amazonian domain. This study aimed to investigate the emissions of nitrous oxide (N 2 O), carbon dioxide (CO 2 ) and methane (CH 4 ) fluxes along an altitudinal transect and the relation between these fluxes and other climatic, edaphic and biological variables (temperature, fine roots, litterfall, and soil moisture). Annual means of N 2 O flux were 3.9 (± 0.4), 1.0 (± 0.1), and 0.9 (± 0.2) ng N cm −2 h −1 at altitudes 100, 400, and 1000 m, respectively. On an annual basis, soils consumed CH 4 at all altitudes with annual means of −1.0 (± 0.2), −1.8 (± 0.3), and −1.6 (± 0.1) mg m −2 d −1 at 100 m, 400 m and 1000 m, respectively. Estimated mean annual fluxes of CO 2 were 3.5, 3.6, and 3.4 µmol m −2 s −1 at altitudes 100, 400 and 1000 m, respectively. N 2 O fluxes were significantly influenced by soil moisture and temperature. Soil-atmosphere exchange of CH 4 responded to changes in soil moisture. Carbon dioxide emissions were strongly influenced by soil temperature. While the temperature gradient observed at our sites is only an imperfect proxy for climatic warming, our results suggest that an increase in air and soil temperatures may result in increases in decomposition rates and gross inorganic nitrogen fluxes that could support consequent increases in soil N 2 O and CO 2 emissions and soil CH 4 consumption.

Soils of tropical forests are important to the global budgets of greenhouse gases. The Brazilian Atlantic Forest is the second largest tropical moist forest area of South America, after the vast Amazonian domain. This study aimed to investigate the emissions of Nitrous Oxide (N₂O) and Carbon Dioxide (CO₂) as well as methane (CH₄) emissions and consumptions along an altitudinal transect and the relation between these fluxes and other climatic, edaphic and biological variables (temperature, fine roots, litterfall, and soil moisture). Annual means of N₂O flux were 2.6 (±0.5), 0.9 (±0.1), and 0.7 (±0.2) ng N cm⁻² h⁻¹ at altitudes 100, 400, and 1000 m, respectively. On an annual basis, soils consumed CH₄ at all altitudes with annual means of −1.0 (±0.2), −1.8 (±0.1), and −1.6 (±0.3) mg m⁻² d⁻¹ at 100 m, 400 m and 1000 m, respectively. Although not sampled in the hottest and wettest portion of the year because of instrument malfunctions, mean fluxes of CO₂ averaged 3.6 (±0.2), 3.5 (±0.3), and 3.1 (±0.3) μmol m⁻² s⁻¹ at altitudes 100, 400 and 1000 m, respectively. N₂O fluxes were significantly influenced by soil moisture and temperature. Soil-atmosphere exchange of methane responded to changes in soil moisture. Carbon dioxide emissions were strongly influenced by soil temperature. While the temperature gradient observed at our sites is only an imperfect proxy for climate warming, our results suggest that increasing temperatures will result in increased in microbial activity with a consequent increase in soil N₂O and CO₂ emissions and soil CH₄ consumption

RESUMO -(Composição florística do estrato arbóreo da Floresta Estacional Semidecidual na Planície Aluvial do rio Doce, Linhares, ES, Brasil). Este trabalho apresenta a flora de espécies arbóreas e palmeiras na floresta estacional semidecidual na planície aluvial do rio Doce, uma área de cerca de 20.000 ha, a partir de Linhares (ES) até próximo à foz no oceano atlântico. Foram determinadas 408 espécies (27 classificadas em gênero) e 59 famílias, entre arbóreas e palmeiras. Por meio da análise de agrupamento, foi evidenciado que a floresta do rio Doce é muito semelhante floristicamente à floresta estacional dos tabuleiros terciários, que estas se agrupam com as florestas estacionais do rio Doce em MG e que, por sua vez, todas estas se agrupam com as florestas ombrófilas do sul da Bahia, sendo o conjunto nitidamente separado das outras formações ombrófilas costeiras. Foram encontradas dezenas de espécies deocorrência restrita ou pouco frequentes em levantamentos na floresta atlântica, enfatizando a importância da área para conservação da biodiversidade. Pelo fato das matas de cacau na região abrangerem mais de 80% dessa área, sugere-se a delimitação de uma Área de Proteção Ambiental, que permita conciliar o cultivo do cacau com a proteção da biodiversidade.Palavras-chave: rio Doce, floresta atlântica, floresta de tabuleiro, composição florística, cacau ABSTRACT -(Floristic composition of the tree layer in Atlantic forest on the rio Doce alluvial floodplain, Espírito Santo State, Brazil). The tree and palm flora was studied in the Atlantic forest of the rio Doce alluvial floodplain, in a 20,000 ha area, between Linhares (Espírito Santo State) and the Atlantic Ocean. The floristic survey recorded 408 species and 59 families. Floristic composition was compared to other forests of São Paulo, Minas Gerais, Bahia and Rio de Janeiro states using cluster analysis. The forest flora of the study area was most similar to that of forests in Espírito Santo, Minas Gerais, and Bahia. Dozens of species in the study area are restricted and rare in Atlantic forest; this area deserves special attention for biodiversity conservation. The Brazilian government should pay heed to the biological importance of this area and declare it an Environmental Protection Area, a type of conservation unit where sustained exploitation of resources is legal. We understand that, in practical terms, this sort of conservation unit is not very efficient in conserving natural resources, but it would be a start and might contribute to improved awareness, especially by local farmers and politicians.