Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
1.
Naturwissenschaften ; 111(4): 33, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38904668

RESUMEN

Some parasitic fungi can increase fitness by modifying the behavior of their hosts. These behaviors are known as extended phenotypes because they favor parasitic gene propagation. Here, we studied three lineages of Ophiocordyceps, a fungus that infects ants, altering their conduct before death. According to fungal strategy, ants may die in leaf litter, with entwined legs in branches, under the moss mat, or biting plant tissue. It is critical for parasites that the corpses stay at these places because Ophiocordyceps exhibit iteroparity, possibly releasing spores in multiple life cycles. Thus, we assumed substrate cadaver permanence as a fungi reproductive proxy and corpse height as a proxy of cadaver removal. We hypothesize that biting vegetation and dying in higher places may increase the permanence of ant corpses while avoiding possible corpse predation on the forest floor. We monitored over a year more than 4000 zombie ants in approximately 15 km2 of undisturbed tropical forest in central Amazonia. Our results show a longer permanence of corpses with increasing ground height, suggesting that the parasites may have better chances of releasing spores and infecting new hosts at these places. We found that the zombie ants that last longer on the substrate die under the moss mat in tree trunks, not necessarily biting vegetation. The biting behavior appears to be the most derived and complex mechanism among Ophiocordyceps syndromes. Our results put these findings under a new perspective, proposing that seemingly less complex behavioral changes are ecologically equivalent and adaptative for other parasite lineages.


Asunto(s)
Hormigas , Fenotipo , Hormigas/fisiología , Hormigas/microbiología , Hormigas/parasitología , Animales , Hypocreales/fisiología , Brasil , Conducta Animal/fisiología , Interacciones Huésped-Parásitos/fisiología
2.
Conserv Biol ; 37(3): e14033, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36349503

RESUMEN

Given the speed at which humans are changing the climate, species with high degrees of endemism may not have time to avoid extinction through adaptation. We investigated through teleconnection analysis the origin of rainfall that determines the phylogenetic diversity of rainforest frogs and the effects of microclimate differences in shaping the morphological traits of isolated populations (which contribute to greater phylogenetic diversity and speciation). We also investigated through teleconnection analysis how deforestation in Amazonia can affect ecosystem services that are fundamental to maintaining the climate of the Atlantic rainforest biodiversity hotspot. Seasonal winds known as flying rivers carry water vapor from Amazonia to the Atlantic Forest, and the breaking of this ecosystem service could lead Atlantic Forest species to population decline and extinction in the short term. Our results suggest that the selection of morphological traits that shape Atlantic Forest frog diversity and their population dynamics are influenced by the Amazonian flying rivers. Our results also suggest that the increases of temperature anomalies in the Atlantic Ocean due to global warming and in the Amazon forest due to deforestation are already breaking this cycle and threaten the biodiversity of the Atlantic Forest hotspot.


Efectos de los ríos voladores de la Amazonía sobre la diversidad y las poblaciones de ranas en la Mata Atlántica Resumen Con la velocidad a la que la humanidad está alterando el clima, puede que las especies con un nivel elevado de endemismo no cuenten con tiempo suficiente para adaptarse y evitar la extinción. Usamos un análisis de teleconexión para investigar el origen de las precipitaciones que determinan la diversidad filogenética de las ranas selváticas y los efectos de las diferencias microclimáticas sobre la determinación de las características morfológicas de las poblaciones aisladas, las cuales contribuyen a una mayor especiación y diversidad filogenética. También utilizamos este análisis para investigar cómo la deforestación en la Amazonía puede afectar los servicios ambientales que son fundamentales para mantener el punto caliente de biodiversidad que es la Mata Atlántica. Los ríos voladores son vientos estacionales que transportan vapor de agua desde la Amazonía hasta la Mata Atlántica; la interrupción de este servicio ambiental podría derivar en la declinación poblacional y la extinción a corto plazo de las especies en este ecosistema. Nuestros resultados sugieren que los ríos voladores de la Amazonía influyen sobre la selección de las características morfológicas que determinan la diversidad de ranas y sus dinámicas poblacionales en la Mata Atlántica. Nuestros resultados también sugieren que el incremento de anomalías térmicas en el Océano Atlántico, causadas por el calentamiento global, y en la Amazonía, causadas por la deforestación, ya están interrumpiendo este ciclo y son una amenaza para la biodiversidad del punto caliente que es la Mata Atlántica.


Asunto(s)
Ecosistema , Bosque Lluvioso , Humanos , Animales , Filogenia , Conservación de los Recursos Naturales , Biodiversidad , Brasil , Anuros
3.
An Acad Bras Cienc ; 95(3): e20230051, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37878914

RESUMEN

Long-term-ecological-research (LTER) faces many challenges, including the difficulty of obtaining long-term funding, changes in research questions and sampling designs, keeping researchers collecting standardized data for many years, impediments to interactions with local people, and the difficulty of integrating the needs of local decision makers with "big science". These issues result in a lack of universally accepted guidelines as to how research should be done and integrated among LTER sites. Here we discuss how the RAPELD (standardized field infrastructure system), can help deal with these issues as a complementary technique in LTER studies, allowing comparisons across landscapes and ecosystems and reducing sampling costs. RAPELD uses local surveys to understand broad spatial and temporal patterns while enhancing decision-making and training of researchers, local indigenous groups and traditional communities. Sampling of ecological data can be carried out by different researchers through standardized protocols, resulting in spatial data that can be used to answer temporal questions, and allow new questions to be investigated. Results can also be integrated into existing biodiversity networks. Integrated systems are the most efficient way to save resources, maximize results, and accumulate information that can be used in the face of the unknown unknowns upon which our future depends.


Asunto(s)
Biodiversidad , Ecosistema , Humanos , Estudios Longitudinales
4.
Oecologia ; 198(1): 193-203, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34853902

RESUMEN

Understanding the direct and indirect effects of niche and neutral processes in structuring species diversity is particularly challenging because environmental factors are often geographically structured. Here, we used Structural Equation Modeling to quantify direct and indirect effects of geographic distance, the Amazon River's opposite margins, and environmental differences in temperature, precipitation, and vegetation density (Normalized Difference Vegetation Index-NDVI) on ant beta diversity (Jaccard's dissimilarity) across Amazon basin. We used a comprehensive survey of ground-dwelling ant species from 126 plots distributed across eight sampling sites along a broad environmental gradient. We found that geographic distance and NDVI differences were the major direct predictors of ant composition dissimilarity. The major indirect effect was that of temperature through NDVI, whereas precipitation neither had direct or indirect detectable effects on beta diversity. Thus, ant compositional dissimilarity seems to be mainly driven by a combination of isolation by distance (through dispersal limitation) and selection imposed by vegetation density, and indirectly, by temperature. Our results suggest that neutral and niche processes have been similarly crucial in driving the current beta diversity patterns of Amazonian ground-dwelling ants.


Asunto(s)
Hormigas , Animales , Biodiversidad , Temperatura
5.
An Acad Bras Cienc ; 93(2): e20201604, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33852672

RESUMEN

The Program for Biodiversity Research (PPBio) is an innovative program designed to integrate all biodiversity research stakeholders. Operating since 2004, it has installed long-term ecological research sites throughout Brazil and its logic has been applied in some other southern-hemisphere countries. The program supports all aspects of research necessary to understand biodiversity and the processes that affect it. There are presently 161 sampling sites (see some of them at Supplementary Appendix), most of which use a standardized methodology that allows comparisons across biomes and through time. To date, there are about 1200 publications associated with PPBio that cover topics ranging from natural history to genetics and species distributions. Most of the field data and metadata are available through PPBio web sites or DataONE. Metadata is available for researchers that intend to explore the different faces of Brazilian biodiversity spatio-temporal variation, as well as for managers intending to improve conservation strategies. The Program also fostered, directly and indirectly, local technical capacity building, and supported the training of hundreds of undergraduate and graduate students. The main challenge is maintaining the long-term funding necessary to understand biodiversity patterns and processes under pressure from global environmental changes.


Asunto(s)
Biodiversidad , Ecosistema , Brasil , Conservación de los Recursos Naturales , Humanos , Conocimiento
6.
J Environ Manage ; 232: 37-44, 2019 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-30468955

RESUMEN

Riparian areas around streams are those areas in which biological communites are directly influenced by the stream. The size of protected riparian areas and their conservation has become a controversial topic after changes implemented in the Brazilian Forest Code (BFC): a set of laws that regulates the size of Permanent Protection Areas (PPA). Here, we investigate the influence of distance from water bodies on bat-species and guild composition in a lowland Amazonian rainforest. Our hypotheses were that bat assemblages would change depending on the distance to the water body and that the abundance of herbivorous bats (frugivorous and nectarivorous) would be greater in areas close to water. Bats were captured with mist-nets in 24 riparian and 25 non-riparian plots within a trail grid in an old-growth terra-firme forest, northeast of Manaus, Amazonas, Brazil. Each plot was sampled three times in a total of 7056 net-hours. We captured 1191 bats, comprising 51 species. We used model selection based on AIC (Akaike Information Criterion) to compare linear and piecewise regressions to estimate the ecological thresholds for different bat assemblages. Piecewise models with one breakpoint were more parsimonious than linear models for abundance data, and the species and guild composition of animalivorous and frugivorous bats. Animalivorous-bat abundance increased from the stream to about 181 m, and frugivorous-bat abundance decreased within 50 m of the stream. The patterns of guild abundance suggest that frugivorous bats may need greater access to streams than animalivorous bats. The most conservative model suggests that most of the variation in bat composition occurs close to the stream and extends to up 114 m from the banks. Therefore, the 30 m wide strip of riparian forest protected by Brazilian law would maintain a relatively small fraction of bat-species assemblages in Ducke Reserve, and is insufficient to represent most of the assemblage-composition variation within the riparian zone. The suggestion to reduce the width of the protected riparian zone from 30 to 15 m for streams smaller than 10 m wide, as is under discussion, would likely be prejudicial for bat assemblages.


Asunto(s)
Quirópteros , Animales , Brasil , Ecosistema , Bosques , Ríos
7.
Glob Chang Biol ; 24(10): 4614-4625, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-29851235

RESUMEN

The relationship between levels of dominance and species richness is highly contentious, especially in ant communities. The dominance-impoverishment rule states that high levels of dominance only occur in species-poor communities, but there appear to be many cases of high levels of dominance in highly diverse communities. The extent to which dominant species limit local richness through competitive exclusion remains unclear, but such exclusion appears more apparent for non-native rather than native dominant species. Here we perform the first global analysis of the relationship between behavioral dominance and species richness. We used data from 1,293 local assemblages of ground-dwelling ants distributed across five continents to document the generality of the dominance-impoverishment rule, and to identify the biotic and abiotic conditions under which it does and does not apply. We found that the behavioral dominance-diversity relationship varies greatly, and depends on whether dominant species are native or non-native, whether dominance is considered as occurrence or relative abundance, and on variation in mean annual temperature. There were declines in diversity with increasing dominance in invaded communities, but diversity increased with increasing dominance in native communities. These patterns occur along the global temperature gradient. However, positive and negative relationships are strongest in the hottest sites. We also found that climate regulates the degree of behavioral dominance, but differently from how it shapes species richness. Our findings imply that, despite strong competitive interactions among ants, competitive exclusion is not a major driver of local richness in native ant communities. Although the dominance-impoverishment rule applies to invaded communities, we propose an alternative dominance-diversification rule for native communities.


Asunto(s)
Hormigas/fisiología , Biodiversidad , Animales , Clima , Ecosistema
8.
Ecology ; 98(3): 883-884, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27984661

RESUMEN

What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51 ,388 ant abundance and occurrence records of more than 2,693 species and 7,953 morphospecies from local assemblages collected at 4,212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type, and degree of disturbance. The aim of compiling this data set was to provide comprehensive species abundance data in order to test relationships between assemblage structure and environmental and biogeographic factors. Data were collected using a variety of standardized methods, such as pitfall and Winkler traps, and will be valuable for studies investigating large-scale forces structuring local assemblages. Understanding such relationships is particularly critical under current rates of global change. We encourage authors holding additional data on systematically collected ant assemblages, especially those in dry and cold, and remote areas, to contact us and contribute their data to this growing data set.


Asunto(s)
Hormigas/fisiología , Bases de Datos Factuales , Ecología , Animales , Hormigas/clasificación , Ecosistema
9.
Am Nat ; 188(5): E126-E133, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27788347

RESUMEN

Among invertebrates, ants are the most abundant and probably most important seed dispersers in both temperate and tropical environments. Crickets, also abundant in tropical forests, are omnivores and commonly attracted to fruits on the forest floor. However, their capability to remove seeds has been reported only once. We compared Marantaceae seed removal by crickets and ants to assess the role of crickets as secondary seed dispersers in Amazonia. Compared with ants, crickets dispersed an equivalent number of seeds and tended to disperse larger seeds farther. However, seed removal by crickets occurs mostly at night, suggesting that removal of arillate seeds by crickets on the tropical forest floor is probably being overlooked or wrongly attributed to other invertebrate groups. One potential consequence of seed dispersal by crickets may be a change in the local spatial distribution of arillate-seed species, due to lower aggregation around ant nests.


Asunto(s)
Bosques , Gryllidae , Dispersión de Semillas , Animales , Hormigas , Frutas , Semillas
10.
Proc Biol Sci ; 282(1808): 20150418, 2015 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-25994675

RESUMEN

Many studies have focused on the impacts of climate change on biological assemblages, yet little is known about how climate interacts with other major anthropogenic influences on biodiversity, such as habitat disturbance. Using a unique global database of 1128 local ant assemblages, we examined whether climate mediates the effects of habitat disturbance on assemblage structure at a global scale. Species richness and evenness were associated positively with temperature, and negatively with disturbance. However, the interaction among temperature, precipitation and disturbance shaped species richness and evenness. The effect was manifested through a failure of species richness to increase substantially with temperature in transformed habitats at low precipitation. At low precipitation levels, evenness increased with temperature in undisturbed sites, peaked at medium temperatures in disturbed sites and remained low in transformed sites. In warmer climates with lower rainfall, the effects of increasing disturbance on species richness and evenness were akin to decreases in temperature of up to 9°C. Anthropogenic disturbance and ongoing climate change may interact in complicated ways to shape the structure of assemblages, with hot, arid environments likely to be at greatest risk.


Asunto(s)
Hormigas/fisiología , Biodiversidad , Clima , Animales , Cambio Climático , Temperatura
11.
PeerJ ; 12: e16986, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38685936

RESUMEN

Environmental heterogeneity poses a significant influence on the functional characteristics of species and communities at local scales. Environmental transition zones, such as at the savanna-forest borders, can act as regions of ecological tension when subjected to sharp variations in the microclimate. For ectothermic organisms, such as lizards, environmental temperatures directly influence physiological capabilities, and some species use different thermoregulation strategies that produce varied responses to local climatic conditions, which in turn affect species occurrence and community dynamics. In the context of global warming, these various strategies confer different types of vulnerability as well as risks of extinction. To assess the vulnerability of a species and understand the relationships between environmental variations, thermal tolerance of a species and community structure, lizard communities in forest-savanna transition areas of two national parks in the southwestern Amazon were sampled and their thermal functional traits were characterized. Then, we investigated how community structure and functional thermal variation were shaped by two environmental predictors (i.e., microclimates estimated locally and vegetation structure estimated from remote sensing). It was found that the community structure was more strongly predicted by the canopy surface reflectance values obtained via remote sensing than by microclimate variables. Environmental temperatures were not the most important factor affecting the occurrence of species, and the variations in ecothermal traits demonstrated a pattern within the taxonomic hierarchy at the family level. This pattern may indicate a tendency for evolutionary history to indirectly influence these functional features. Considering the estimates of the thermal tolerance range and warming tolerance, thermoconformer lizards are likely to be more vulnerable and at greater risk of extinction due to global warming than thermoregulators. The latter, more associated with open environments, seem to take advantage of their lower vulnerability and occur in both habitat types across the transition, potentially out-competing and further increasing the risk of extinction and vulnerability of forest-adapted thermoconformer lizards in these transitional areas.


Asunto(s)
Lagartos , Microclima , Bosque Lluvioso , Animales , Lagartos/fisiología , Pradera , Brasil , Calentamiento Global
12.
Ecol Evol ; 13(1): e9718, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36620401

RESUMEN

The seasonal flood pulse in Amazonia can be considered a primary driver of community structure in floodplain environments. Although this natural periodic disturbance is part of the landscape dynamics, the seasonal inundation presents a considerable challenge to organisms that inhabit floodplain forests. The present study investigated the effect of seasonal flooding on fruit-feeding butterfly assemblages in different forest types and strata in central Amazonia. We sampled fruit-feeding butterflies in the canopy and the understory using baited traps in adjacent upland (unflooded forests-terra firme), white and blackwater floodplain forests (várzea and igapó, respectively) during the low- and high-water seasons. Butterfly abundance decreased in the high-water season, especially of dominant species in várzea, but the number of species was similar between seasons in the three forest types. Species composition differed between strata in all forest types. However, the flood pulse only affected butterfly assemblages in várzea forest. The ß-diversity components also differed only in várzea. Species replacement (turnover) dominated the spatial ß-diversity in igapó and terra firme in both seasons and várzea in the high-water season. Nonetheless, nestedness was relatively higher in várzea forests during the low-water season, mainly due to the effect of dominant species. These results emphasize the importance of seasonal flooding to structure butterfly assemblages in floodplain forests and reveal the idiosyncrasy of butterfly community responses to flooding in different forest types. Our results also suggest that any major and rapid changes to the hydrological regime could severely affect floodplain communities adapted to this natural seasonal hydrological cycle, threatening the existence of these unique environments.

13.
Ecol Evol ; 13(12): e10783, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38053788

RESUMEN

Medium to large rainforest mammals are key conservation flagship groups that offer non-redundant ecosystem functions, but anthropic pressures, such as illegal hunting, may strongly affect their occupancy in Amazonia. We combined camera traps and occupancy models to assess the influence of distance from human settlements, the number of families per settlement and the synergetic effect of the average weight of 27 species on the occupancy probability of mammals. Specifically, we classified mammal species according to the game preferences of hunters (i.e. a group of species depleted for bushmeat, a group of species hunted for retaliation and a group of non-hunted species). We also accounted for the influence on the detection probability of each group of both the number of days each camera operated and the body weight of mammals. The occupancy probability of the bushmeat group (i.e. deer, peccaries, agoutis, pacas and armadillos) was lower at locations closer to human settlements. Still, the number of families correlated positively with occupancy, with the occupancy probability of the group being slightly higher at sites with more families. This difference was probably due to larger and more abundant crops and fruiting trees attracting wildlife at such sites. Conversely, the occupancy probability of the retaliation group (i.e. carnivores) and the non-hunted group (i.e. opossums, spiny rats, squirrels and anteaters) were indifferent to anthropogenic stressors. The detection probability of the non-hunted and particularly the most depleted species correlated negatively with body weight. This may suggest that larger species, especially those from the bushmeat group, are rarer or less abundant in the system, possibly because they are the preferable target of hunters. In the long term, locals will likely need to travel long distances to find harvest meat. Poaching also threatens food security since game bushmeat is an essential source of protein for isolated rural Amazonians.

14.
Curr Biol ; 33(16): 3495-3504.e4, 2023 08 21.
Artículo en Inglés | MEDLINE | ID: mdl-37473761

RESUMEN

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%-18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost.


Asunto(s)
Biodiversidad , Bosques , Humanos , Bosque Lluvioso , Brasil , Clima Tropical , Conservación de los Recursos Naturales , Ecosistema
15.
R Soc Open Sci ; 10(2): 221170, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36778958

RESUMEN

Research findings in natural sciences need to be comparable and reproducible to effectively improve our understanding of ecological and behavioural patterns. In this sense, knowledge frontiers in biodiversity studies are directly tied to taxonomic research, especially in species-rich tropical regions. Here we analysed the taxonomic information available in 470 studies on Brazilian ant diversity published in the last 50 years. We aimed to quantify the proportion of studies that provide enough data to validate taxonomic identification, explore the frequency of studies that properly acknowledge their taxonomic background, and investigate the primary resources for ant identification in Brazil. We found that most studies on Brazilian ant diversity (73.6%) explicitly stated the methods used to identify their specimens. However, the proportion of papers that provide complete data for the repository institutions and vouchered specimens is vanishingly small (5.8%). Additionally, only 40.0% of the studies consistently presented taxon authorities and years of description, rarely referencing taxonomic publications correctly. In turn, the number of specialists and institutions consulted for ant identification in Brazil has increased in the last years, along with the number of studies that explicitly provide their taxonomic procedures for ant identification. Our findings highlight a shift between generations regarding the recognition of taxonomy as fundamental science, deepening our understanding of biodiversity.

16.
Primates ; 62(1): 199-206, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32862373

RESUMEN

Terrestriality in Platyrrhine primates is primarily associated with low arboreal resource availability, low predation risk when on the ground and increased contact time with human observers. To test the relationship between these variables and ground use frequency, we studied a group of endangered Coimbra-Filho's titi monkeys (Callicebus coimbrai) in a 14-ha forest fragment in north-eastern Brazil. Terrestriality data were collected on a monthly basis (33 months) using scan sampling procedures from July 2008 to July 2012. Overall, Coimbra-Filho's titi monkeys were recorded during 0.6% of observation time (113 out of 18,164 scans) on the ground. Most of the time on the ground was spent feeding on young leaves (71 records) and the least amount of time on fruits (14 records). Availability of arboreal foods, rainfall, and time of contact with human observers did not influence overall terrestrial behaviour (ground use). However, the timing and nature of the monkeys' terrestrial feeding was strongly related to the absence of arboreal fruit (ß-estimate = -3.078) and young leaf (ß-estimate = -3.515) food resources. We suggest that terrestrial feeding by Coimbra-Filho's titi monkeys could be an adaptation to low arboreal fruit availability and the exploitation of alternative food resources.


Asunto(s)
Conducta Alimentaria , Pitheciidae/fisiología , Animales , Brasil , Dieta , Especies en Peligro de Extinción , Femenino , Frutas , Masculino , Hojas de la Planta , Estaciones del Año
17.
PLoS One ; 16(10): e0257875, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34597306

RESUMEN

Plants have been used in Amazonian forests for millennia and some of these plants are disproportionally abundant (hyperdominant). At local scales, people generally use the most abundant plants, which may be abundant as the result of management of indigenous peoples and local communities. However, it is unknown whether plant use is also associated with abundance at larger scales. We used the population sizes of 4,454 arboreal species (trees and palms) estimated from 1946 forest plots and compiled information about uses from 29 Amazonian ethnobotany books and articles published between 1926 and 2013 to investigate the relationship between species usefulness and their population sizes, and how this relationship is influenced by the degree of domestication of arboreal species across Amazonia. We found that half of the arboreal species (2,253) are useful to humans, which represents 84% of the estimated individuals in Amazonian forests. Useful species have mean populations sizes six times larger than non-useful species, and their abundance is related with the probability of usefulness. Incipiently domesticated species are the most abundant. Population size was weakly related to specific uses, but strongly related with the multiplicity of uses. This study highlights the enormous usefulness of Amazonian arboreal species for local peoples. Our findings support the hypothesis that the most abundant plant species have a greater chance to be useful at both local and larger scales, and suggest that although people use the most abundant plants, indigenous people and local communities have contributed to plant abundance through long-term management.


Asunto(s)
Biodiversidad , Plantas , Brasil , Domesticación , Etnobotánica , Humanos
18.
PeerJ ; 8: e9322, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32547889

RESUMEN

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.

19.
Science ; 368(6493): 869-874, 2020 05 22.
Artículo en Inglés | MEDLINE | ID: mdl-32439789

RESUMEN

The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (-9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth's climate.


Asunto(s)
Ciclo del Carbono , Cambio Climático , Bosques , Calor , Árboles/metabolismo , Clima Tropical , Aclimatación , Biomasa , Carbono/metabolismo , Planeta Tierra , Madera
20.
Rev Soc Bras Med Trop ; 52: e20190063, 2019 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-31271624

RESUMEN

INTRODUCTION: The present study reports the presence of triatomines in natural, peridomestic, and intradomicile environments in Itacoatiara municipality, state of Amazonas, a non-endemic region for Chagas disease. METHODS: Active search was performed inside tree trunks, and palm trees, residences, and peridomiciles localized near the forest area. RESULTS: Twenty adults and ten triatomines nymphs were collected, fifteen of which were from natural forests, thirteen from intradomiciles, and two from peridomicile areas. CONCLUSIONS: The new records of adults and nymphs of triatomines in the intra- and peridomiciles suggest the adoption of prophylactic measures for vector surveillance in the study area.


Asunto(s)
Insectos Vectores/parasitología , Triatominae/parasitología , Distribución Animal , Animales , Brasil , Enfermedad de Chagas/transmisión , Femenino , Bosques , Vivienda , Insectos Vectores/clasificación , Densidad de Población , Triatominae/clasificación , Trypanosoma cruzi/aislamiento & purificación
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA