There is evidence that COVID-19, the disease caused by the betacoronavirus SARS-CoV-2, is sensitive to environmental conditions. However, such conditions often correlate with demographic and socioeconomic factors at larger spatial extents, which could confound this inference. We evaluated the effect of meteorological conditions (temperature, solar radiation, air humidity and precipitation) on 292 daily records of cumulative number of confirmed COVID-19 cases across the 27 Brazilian capital cities during the 1st month of the outbreak, while controlling for an indicator of the number of tests, the number of arriving flights, population density, proportion of elderly people and average income. Apart from increasing with time, the number of confirmed cases was mainly related to the number of arriving flights and population density, increasing with both factors. However, after accounting for these effects, the disease was shown to be temperature sensitive: there were more cases in colder cities and days, and cases accumulated faster at lower temperatures. Our best estimate indicates that a 1 °C increase in temperature has been associated with a decrease in confirmed cases of 8%. The quality of the data and unknowns limit the analysis, but the study reveals an urgent need to understand more about the environmental sensitivity of the disease to predict demands on health services in different regions and seasons.
Aim Despite the accelerating loss of biodiversity and the increased number of methods for conservation planning, the availability of information about the spatial distribution of biodiversity remains limited. One way to overcome this problem is to focus on surrogate resolutions that are able to represent specieslevel data and can be efficiently measured. Surrogates are only useful if the ecological patterns detected at the species-level still hold when based on coarser taxonomic identification, and if these responses are consistent across regions. We present a comprehensive analysis using data from a large-scale evaluation of ground-dwelling ants, to evaluate the use of surrogates.Location Amazon basin.Methods The sampling design covered 13 sites in eight phytophysiognomies, which in conjunction with other environmental characteristics (altitude, soil granulometry and slope) were used to validate the ecological patterns (ability of the surrogates to reproduce the ecological responses identified for species) of coarser surrogate taxa (indicator taxa, mixed-level approach, genus and subfamily). The surrogates were evaluated for their capacity to predict variation in total species richness and composition. We also estimated the monetary and time costs, in order to evaluate the cost-effectiveness of using different surrogate levels.Results Genus was the most cost-effective surrogate: it predicted 81% of site variation in species richness, was highly correlated (r 2 = 0.76) with species composition, very highly correlated (r 2 = 0.97) with ecological patterns detected at species level and saved~40% of total project costs. The mixed-level approach, indicator taxa and subfamily were not effective in representing the species-level data.Main conclusions Genus can be used as a surrogate for species, due to its high predictive value, independent of environmental heterogeneity. Genus may be useful as a surrogate for species in other megadiverse regions, especially where savings in project costs can be applied to increase sampling effort.
The intensity and frequency of severe droughts in the Amazon region have increased in the recent decades. These extreme events are associated with changes in forest dynamics, biomass and floristic composition. However, most studies of drought response have focused on upland forests with deep water tables, which may be especially sensitive to drought. Palms, which tend to dominate the less well‐drained soils, have also been neglected. The relative neglect of shallow water tables and palms is a significant concern for our understanding of tropical drought impacts, especially as one‐third of Amazon forests grow on shallow water tables (<5 m deep). We evaluated the drought response of palms and trees in forests distributed over a 600 km transect in central‐southern Amazonia, where the landscape is dominated by shallow water table forests (SWTF). We compared vegetation dynamics before and following the 2015–2016 El Nino drought, the hottest and driest on record for the region (−214 mm of cumulative water deficit). We observed no change in stand mortality rates and no biomass loss in response to drought in these forests. Instead, we observed an increase in recruitment rates, which doubled to 6.78% year‐1 ± 4.40 (M ± SD) during 2015–2016 for palms and increased by half for trees (to 2.92% year‐1 ± 1.21), compared to rates in the pre‐El‐Nino interval. Within these SWTF, mortality and recruitment rates varied as a function of climatic drought intensity and water table depth for both palms and trees, with mortality being greatest in climatically and hydrologically wetter environments and recruitment greatest in drier environments. Across our transect, there was a significant increase over time in tree biomass. Synthesis. Our results indicate that forests growing over shallow water tables—relatively under‐studied vegetation that nonetheless occupies one‐third of Amazon forests—are remarkably resistant to drought. These findings are consistent with the hypothesis that local hydrology and its interactions with climate strongly constrain forest drought effects, and has implications for climate change feedbacks. This work enhances our understanding of integrated drought effects on tropical forest dynamics and highlights the importance of incorporating neglected forest types into both the modelling of forest climate responses and into public decisions about priorities for conservation.
Colony size is often attributed a key role in social insect population ecology. However, in nest‐building termites, colony size is a power function of nest volume, so that colonies of species with low scaling exponents tend to grow less as their nests are expanded. Thus, in such species, intercolonial differences in colony size may be less likely to develop, and changes in species total biomass may largely reflect those in colony numbers rather than colony sizes. The scaling of colony biomass with nest volume in three termite species, namely Anoplotermes banksiEmerson, Neocapritermes braziliensis Snyder and Labiotermes labralis Holmgren was determined. Then, their nests were counted and their total biomass in plots across an Amazonian rainforest landscape was estimated. Finally, whether the strength of the relationship between total biomass and number of nests reflected species scaling exponents was examined. Scaling exponents were 0.47 for N. braziliensis, 0.57 for A. banksi, and 0.83 for L. labralis. On the other hand, the strength of the relationship between total biomass and the number of nests (r2) followed the opposite trend: 0.93 for N. braziliensis, 0.92 for A. banksi, and 0.53 for L. labralis. It is suggested that the scaling of colony size with nest volume may mediate termite population dynamics: as the scaling exponent decreases across species, changes in total biomass would increasingly reflect changes in colony numbers, with an accompanying increase in the importance of colony births and deaths as opposed to colony growth.
This study investigated the spatial distribution of an Amazonian fruit-feeding butterfly assemblage by linking species taxonomic and functional approaches. We hypothesized that: 1) vegetation richness (i.e., resources) and abundance of insectivorous birds (i.e., predators) should drive changes in butterfly taxonomic composition, 2) larval diet breadth should decrease with increase of plant species richness, 3) small-sized adults should be favored by higher abundance of birds, and 4) communities with eyespot markings should be able to exploit areas with higher predation pressure. Fruit-feeding butterflies were sampled with bait traps and insect nets across 25 km(2) of an Amazonian ombrophilous forest in Brazil. We measured larval diet breadth, adult body size, and wing marking of all butterflies. Our results showed that plant species richness explained most of the variation in butterfly taxonomic turnover. Also, community average diet breadth decreased with increase of plant species richness, which supports our expectations. In contrast, community average body size increased with the abundance of birds, refuting our hypothesis. We detected no influence of environmental gradients on the occurrence of species with eyespot markings. The association between butterfly taxonomic and functional composition points to a mediator role of the functional traits in the environmental filtering of butterflies. The incorporation of the functional approach into the analyses allowed for the detection of relationships that were not observed using a strictly taxonomic perspective and provided an extra insight into comprehending the potential adaptive strategies of butterflies.
1. Metabolic rate (B) is a fundamental property of organisms, and scales with body mass (M) as B = αMβ. There has been much debate on whether scaling parameters should be viewed as constants or variables. However, there is increasing evidence that ecological differentiation can affect both α and β. 2. In colonial organisms such as social insects, individual metabolism is integrated at the colony level. Theory and data suggest that whole‐colony metabolism partly reflects individual‐level metabolic and life‐history scalings, but whether these have been affected by ecological diversification is little known. 3. Here, this issue was addressed using termites. Data from the literature were assembled to assess the interspecific scalings of individual metabolic rate with individual mass, and of individual mass with colony mass. Concurrently, it was tested whether such scalings were affected by two key ecological traits: lifestyle and diet. 4. Individual‐level metabolic scaling was affected by diet, with β = 1.02 in wood feeders and 0.60 in soil feeders. However, there was no difference in α. Further, individual mass scaled to the 0.25 power with colony mass, but forager species had larger colonies and smaller individuals relative to wood‐dwelling, sedentary ones, thus producing a grade shift. 5. Our results show that ecological diversification has affected fundamental metabolic and life‐history scalings in termites. Thus, theory on the energetics and evolution of colonial life should account for this variability.
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