Estimating aboveground net biomass change for tropical and subtropical forests: Refinement of IPCC default rates using forest plot data.

As countries advance in greenhouse gas (GHG) accounting for climate change mitigation, consistent estimates of aboveground net biomass change (∆AGB) are needed. Countries with limited forest monitoring capabilities in the tropics and subtropics rely on IPCC 2006 default ∆AGB rates, which are values per ecological zone, per continent. Similarly, research into forest biomass change at a large scale also makes use of these rates. IPCC 2006 default rates come from a handful of studies, provide no uncertainty indications and do not distinguish between older secondary forests and old-growth forests. As part of the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, we incorporate ∆AGB data available from 2006 onwards, comprising 176 chronosequences in secondary forests and 536 permanent plots in old-growth and managed/logged forests located in 42 countries in Africa, North and South America and Asia. We generated ∆AGB rate estimates for younger secondary forests (≤20 years), older secondary forests (>20 years and up to 100 years) and old-growth forests, and accounted for uncertainties in our estimates. In tropical rainforests, for which data availability was the highest, our ∆AGB rate estimates ranged from 3.4 (Asia) to 7.6 (Africa) Mg ha-1  year-1 in younger secondary forests, from 2.3 (North and South America) to 3.5 (Africa) Mg ha-1  year-1 in older secondary forests, and 0.7 (Asia) to 1.3 (Africa) Mg ha-1  year-1 in old-growth forests. We provide a rigorous and traceable refinement of the IPCC 2006 default rates in tropical and subtropical ecological zones, and identify which areas require more research on ∆AGB. In this respect, this study should be considered as an important step towards quantifying the role of tropical and subtropical forests as carbon sinks with higher accuracy; our new rates can be used for large-scale GHG accounting by governmental bodies, nongovernmental organizations and in scientific research.

Seed local adaptation and seedling plasticity account for Gleditsia triacanthos tree invasion across biomes.

BACKGROUND AND AIMS: Phenotypic plasticity and local adaption can contribute to the success of invasive species. While the former is an environmentally induced trait, the latter involves a selection process to filter the best genotype for a location. We examined the evidence for phenotypic plasticity and local adaptation for seed and seedling traits of the invasive tree Gleditsia triacanthos, with three origins distributed along an approx. 10° latitude gradient across three biomes. METHODS: In sub-tropical forests, dry woodlands and secondary temperate grasslands in Argentina, we harvested seeds from clusters of neighbouring trees (i.e. families) distributed within 15-20 km in each origin (biome). We manipulated the environmental conditions relevant to each biome, assuming that propagule availability did not represent an ecological barrier. In growth chambers, we evaluated seed imbibition and seed germination under different light, temperature and water potential. In a 2 year common garden, we evaluated the impact of resident vegetation removal on seedling survival and growth. KEY RESULTS: Mean time to complete seed imbibition differed among origins; seeds from temperate grasslands reached full imbibition before seeds from dry woodlands and sub-tropical forests. Germination was always >70 %, but was differentially affected by water potential, and light quantity (dark-light) and quality (red-far red) among origins, suggesting local adaptation. In the common garden, vegetation removal rather than origin negatively affected seedling survival and enhanced seedling growth. Vegetation removal increased basal diameter, leaves per plant and spine number, and reduced the height:basal diameter ratio. CONCLUSIONS: We conclude that local adaptation in seed germination traits and plastic changes in seedling allometry (e.g. height:diameter) may allow this tree to respond over the short and long term to changes in environmental conditions, and to contribute to shape G. triacanthos as a successful woody invader. Overall, our study revealed how local adaptation and plasticity can explain different aspects of tree invasion capacity across biomes.

Direct and indirect effects of a pH gradient bring insights into the mechanisms driving prokaryotic community structures.

BACKGROUND: pH is frequently reported as the main driver for prokaryotic community structure in soils. However, pH changes are also linked to "spillover effects" on other chemical parameters (e.g., availability of Al, Fe, Mn, Zn, and Cu) and plant growth, but these indirect effects on the microbial communities are rarely investigated. Usually, pH also co-varies with some confounding factors, such as land use, soil management (e.g., tillage and chemical inputs), plant cover, and/or edapho-climatic conditions. So, a more comprehensive analysis of the direct and indirect effects of pH brings a better understanding of the mechanisms driving prokaryotic (archaeal and bacterial) community structures. RESULTS: We evaluated an agricultural soil pH gradient (from 4 to 6, the typical range for tropical farms), in a liming gradient with confounding factors minimized, investigating relationships between prokaryotic communities (16S rRNA) and physical-chemical parameters (indirect effects). Correlations, hierarchical modeling of species communities (HMSC), and random forest (RF) modeling indicated that both direct and indirect effects of the pH gradient affected the prokaryotic communities. Some OTUs were more affected by the pH changes (e.g., some Actinobacteria), while others were more affected by the indirect pH effects (e.g., some Proteobacteria). HMSC detected a phylogenetic signal related to the effects. Both HMSC and RF indicated that the main indirect effect was the pH changes on the availability of some elements (e.g., Al, Fe, and Cu), and secondarily, effects on plant growth and nutrient cycling also affected the OTUs. Additionally, we found that some of the OTUs that responded to pH also correlated with CO2, CH4, and N2O greenhouse gas fluxes. CONCLUSIONS: Our results indicate that there are two distinct pH-related mechanisms driving prokaryotic community structures, the direct effect and "spillover effects" of pH (indirect effects). Moreover, the indirect effects are highly relevant for some OTUs and consequently for the community structure; therefore, it is a mechanism that should be further investigated in microbial ecology.

Influence of cypermethrin on avoidance behavior, survival and reproduction of Folsomia candida in soil.

Cypermethrin is a pyrethroid widely used in agriculture and in control of animal ectoparasites, being effective against a large number of insects. Therefore, this study aimed to evaluate the effects of cypermethrin on soil fauna using reproduction and behavior ecotoxicological tests with the springtail Folsomia candida. The surface layer of a soil characteristic of the western region of the Santa Catarina State, classified as Typic Dystrupept, was used as test substrate. The treatments on both tests consisted of five concentrations of cypermethrin (0, 7.5, 15.0, 22.5, and 30.0mgkg(-)(1)) corresponding to 0, 1.5, 3.0, 4.5, and 6.0gm(-2), respectively. This range was chosen according to technical instruction for the use of this product in broilers beds (that are used afterwards as organic fertilizer in soil) that recommends 15mgkg(-1) (3.0gm(-2)). The results obtained with tests for F. candida showed toxicity at all doses tested, following a dose-related response resulting in reduction in survival rate (LC50 of 18.41mgkg(-1), equivalent to 3.8gm(-2)), in the number of juveniles (EC50 of 15.05mgkg(-1), corresponding to 3.01gm(-2)), and an increase in avoidance response (AC50 of 29mgkg(-1), corresponding to 5.8gm(-2)). Although more studies are needed focusing on the fate of cypermethrin in soil when the poultry beds are used as fertilizer and how it may affect soil fauna, data obtained in this study, by showing effects within the range of the doses that are recommended implies that caution and possible mitigation measures should be taken when using this compound.

Socio-economic characteristics of the Cachoeira de Emas small-scale fishery in Mogi-Guaçu River, State of São Paulo, Brazil / Características socioeconômicas da pesca profissional de pequena escala na cachoeira de Emas, Rio Mogi-Guaçu, Estado de São Paulo (Brasil)

Fishing in the area of Cachoeira de Emas dates from the aboriginal Painguás who inhabited its margins. The socioeconomic conditions of the fishers and fishing are described, derived from personal interviews with 33 fishers. Their mean age is 48.6 years and they have been fishing on average for 24.2 years. The monthly total raw income is US$ 575.52 and the raw income just from fishing is of US$ 239.64 per fisher. Most of them (66.6 percent) have only incomplete primary and junior education. The main capture species are curimba Prochilodus lineatus, piapara Leporinus obtusidens, dourado Salminus brasiliensis, mandi Pimelodus maculatus, Pimelodus heraldoi and lambari (genus Astyanax and Roeboides). Fishers capture an average of 19.9 kg of fish per day. The total average raw income just calculated from the interviews is very high when compared with other places in Brazil and in the world, and above the poverty line as defined by the Getúlio Vargas Foundation. So we may conclude there these fishers are not the poorest in society.

A pesca na região da Cachoeira de Emas ocorre desde quando os indígenas habitavam suas margens. As condições socioeconômicas dos pescadores que atuam neste local e a caracterização da pesca foram determinadas através de entrevistas com 33 pescadores. A idade média deles é de 48,6 anos e eles vêm pescando em média por 24,2 anos. A renda mensal total familiar é de US$ 575,52 e a renda apenas da pesca é de US$ 239,64 por pescador. A maioria deles tem o primeiro grau incompleto (66,6 por cento). As principais espécies capturadas são o curimba Prochilodus lineatus, a piapara Leporinus obtusidens, o dourado Salminus brasiliensis, o mandi Pimelodus maculatus, Pimelodus heraldoi e o lambari (gênero Astyanax e Roeboides). Os pescadores capturam em média 19,9 kg por dia. Comparando-se a captura média diária por pescador na Cachoeira de Emas com outros lugares percebemos que ela ainda está acima da média. A renda média total está entre as mais altas comparando-se com outros locais do Brasil e do mundo e acima da linha de miséria definida pela Fundação Getúlio Vargas. Podemos então concluir que estes pescadores não são a classe de profissionais mais pobres da sociedade.

Socio-economic characteristics of the Cachoeira de Emas small-scale fishery in Mogi-Guaçu River, State of São Paulo, Brazil

Fishing in the area of Cachoeira de Emas dates from the aboriginal Painguás who inhabited its margins. The socioeconomic conditions of the fishers and fishing are described, derived from personal interviews with 33 fishers. Their mean age is 48.6 years and they have been fishing on average for 24.2 years. The monthly total raw income is US$ 575.52 and the raw income just from fishing is of US$ 239.64 per fisher. Most of them (66.6%) have only incomplete primary and junior education. The main capture species are curimba Prochilodus lineatus, piapara Leporinus obtusidens, dourado Salminus brasiliensis, mandi Pimelodus maculatus, Pimelodus heraldoi and lambari (genus Astyanax and Roeboides). Fishers capture an average of 19.9 kg of fish per day. The total average raw income just calculated from the interviews is very high when compared with other places in Brazil and in the world, and above the poverty line as defined by the Getúlio Vargas Foundation. So we may conclude there these fishers are not the poorest in society.

A pesca na região da Cachoeira de Emas ocorre desde quando os indígenas habitavam suas margens. As condições socioeconômicas dos pescadores que atuam neste local e a caracterização da pesca foram determinadas através de entrevistas com 33 pescadores. A idade média deles é de 48,6 anos e eles vêm pescando em média por 24,2 anos. A renda mensal total familiar é de US$ 575,52 e a renda apenas da pesca é de US$ 239,64 por pescador. A maioria deles tem o primeiro grau incompleto (66,6%). As principais espécies capturadas são o curimba Prochilodus lineatus, a piapara Leporinus obtusidens, o dourado Salminus brasiliensis, o mandi Pimelodus maculatus, Pimelodus heraldoi e o lambari (gênero Astyanax e Roeboides). Os pescadores capturam em média 19,9 kg por dia. Comparando-se a captura média diária por pescador na Cachoeira de Emas com outros lugares percebemos que ela ainda está acima da média. A renda média total está entre as mais altas comparando-se com outros locais do Brasil e do mundo e acima da linha de miséria definida pela Fundação Getúlio Vargas. Podemos então concluir que estes pescadores não são a classe de profissionais mais pobres da sociedade.