Motivation: Leaf traits represent an important component of plant functional strategies, and those related to carbon fixation and nutrient acquisition form the leaf economics spectrum. However, observations of functional leaf traits are underrepresented in tropical regions in comparison with those in temperate areas. Brazil, a country with continental scale and vast biodiversity is a timely example, where many biomes are impacted by human activities and climate change. However, leaf traits relevant to understand vegetation responses to these impacts remain poorly quantified for many species found in the country. We compiled an extensive data set of four functional leaf traits for native woody species occurring in the Brazilian territory. In addition to trait observations, sampling dates and geo-references were compiled and climatic parameters and soil properties of each sampling site were extracted from several databases. Main types of variables contained:The LT-Brazil data set contains 3,479, 1,216, 775 and 775 clean observations of leaf mass per area, leaf nitrogen (N) concentration per unit mass, leaf phosphorus (P) concentration per unit mass, and leaf N : P ratio, respectively, from native woody species, encompassing information of biome, vegetation, taxonomic data, geographical coordinates, climatic parameters, as well as soil properties. Spatial location and grain: We compiled trait observations from 223 sites under native vegetation distributed in all main biomes (i.e., Amazônia, Caatinga, Cerrado, Mata Atlântica, Pampa and Pantanal) across the Brazilian territory. Time period and grain: The data represent information published and/or sampled during the last 25 years.| 2137 MARIANO et Al.
This paper results from discussions triggered during the "Stream Ecology Symposium" that took place at the XIII Congress of the Brazilian Society of Limnology in September of 2011 in Natal, Brazil. Based on our experiences, we have raised several questions regarding ecological studies of headwater streams facing threats under global-changes and proposed numerous subjects to be addressed in future studies in Brazil. These studies deal with the necessity of knowing species biology and the elaboration of models to assess changes (which implies the availability of time-series or large-scale data sets); the ecology of riparian zones and the interchange of materials and energy across the land-water boundaries; forest conversions and standardized sampling strategies and data treatment to assess global change.
The breakdown of allochthonous plants is of great importance in providing energy and nutrients in streams. In this regard, shredder macroinvertebrates play an important role in decomposing organic matter. Changes in land use strongly influence the type of material entering a stream, which ultimately affects the food chain dependent on this material. This study compared the decay of C3 (Mollinedia schottiana) and C4 (Brachiaria brizantha) plants in the montane Atlantic Forest of Brazil using litterbag experiments in two streams draining watersheds of different land uses. Concomitantly, we investigated the colonisation and assimilation of these plant detritus by aquatic macroinvertebrates. The breakdown of C4 plants in the forest stream was faster than that of C3 plants; however, aquatic macroinvertebrates did not assimilate the C4 carbon. These results support other studies that have shown a greater abundance of shredders in montane tropical streams (lower temperature) than in lowland streams. Moreover, the findings of this study support the view that changes in land use alter the structure of the benthic community, and that these changes can alter the leaf breakdown process.
The breakdown of allochthonous organic matter is considered to be the main source of energy and nutrients for the majority of first-order streams. Thus, land-use change and riparian vegetation, such as deforestation and conversion of native forest to pasture lands, will lead to unwanted changes of the structure and function of aquatic ecosystems due to the disturbance of organic-matter supply. The C4 grasses, extensively used as forage in tropical regions, are poorly studied as important sources of allochthonous material because they are usually considered as a poor source of nutrients. Because the effects of land-use change on ecosystem functions are not fully known, we aimed to evaluate how such changes in riparian vegetation can affect nutrient cycling by means of measuring the decomposition rate of an abundant native C3 species and an exotic C4 grass species in first-order streams of the Atlantic Forest. Our results showed that C4 detritus decomposed faster than did C3 detritus, despite its lower nutrient concentration. This was likely to be due to the lower lignin concentration of the C4 species than the native C3 species. Lignin also influenced nutrient-loss dynamics of the C3 species, because it can interact with other cellular constituents and prevent the decomposition of most labile compounds. Our results supported the observation that the replacement of riparian vegetation alters breakdown rates and nutrient distributions, which may disrupt aquatic food webs.
Terrestrial invertebrates link terrestrial systems to aquatic ones, making vegetal material produced in the watershed available to aquatic food webs. In this study, using carbon and nitrogen stable isotopes, we evaluated the importance of introduced C4 grasses as a source of carbon in aquatic food webs of headwater streams of the coastal Atlantic Forest located on the north coast of the State of São Paulo, in the southeastern region of Brazil. Terrestrial invertebrates were collected in two streams: one where the main land cover was pristine montane Atlantic Forest (forest stream) and another where the main land cover was introduced C4 forage grasses for livestock (pasture stream). The average δ13C of terrestrial invertebrates collected in the forest stream (−26.3±2.1‰) was significantly (p<0.01) smaller than the average δ13C of terrestrial invertebrates collected in the pasture stream (−15.7±4.7‰), denoting a larger contribution of C4grasses to terrestrial invertebrates of the pasture stream. The average δ15N of terrestrial invertebrates of the forest stream (4.1±2.4‰) was significantly (p<0.01) lower than the average δ15N of terrestrial invertebrates of the pasture stream (9.5±2.7‰). The relative contribution of C3 and C4 plants to terrestrial invertebrates was estimated using SIAR. In the forest stream, the C3 contribution was on average 0.75 (0.72 minimum to 0.79 maximum), and the C4 contribution was on average 0.25 (0.21 minimum to 0.28 maximum). In the pasture stream, the C3contribution decreased to 0.20 (0.14 minimum to 0.26 maximum), and the C4 contribution increased to 0.80 (0.74 minimum to 0.86 maximum). These results have several implications for the ecosystem functioning as well as for recent changes in environmental policies of Brazil. The lower nutritional value of C4 grasses may not only decrease invertebrate performance, but also alter the stoichiometry of several components of the aquatic food webs with potential consequence for the whole ecosystem functioning. On the public policy side, recent changes in the Brazilian Forest Act, a series of laws that regulate land cover at the property level, reduced the width of the forested riparian area with potentially dangerous consequences for aquatic ecosystems.
Motivation SIA‐BRA is a data set that compiles stable carbon (C) and nitrogen (N) isotope ratios of terrestrial and aquatic animals sampled in Brazilian biomes and coastal marine areas. Stable isotope ratios are helpful in animal ecology for several reasons; for instance, they can be used to investigate trophic niches, energy sources (diet tracing) and to track migration patterns. The Neotropics are considered one of the most undersampled regions of the world. Given that Brazil is a continental country where most of the dietary ecology of animal species is under‐assessed, we believe that the SIA‐BRA can provide important complementary information to address this gap in the literature. Additionally, the SIA‐BRA data set allows future investigations to address many questions concerning diet tracing, habitat use, food webs, foraging ecology, physiological aspects and effects of phylogeny on dietary ecology. Main type of variable investigated Carbon and nitrogen stable isotope ratios for terrestrial and aquatic animals. Spatial location and grain The SIA‐BRA included animal tissues sampled in 964 sites in the main Brazilian biomes and coastal marine areas. Time period The data represent information published and/or sampled from 1984 to 2021. Major taxa studied and measurement level The SIA‐BRA contains isotopic data of c. 21,804 non‐captive wildlife specimens, excluding livestock production or laboratory experiments. They were 13,881 vertebrates and 7,923 invertebrates. They were divided into the following habitats: terrestrial (30% of the total), freshwater (27%), oceanic (40%) and estuarine (4%). There were 11 phyla, with a clear dominance of Chordata (64%) and Arthropoda (29%), 36 classes, 154 orders, 473 families, 894 genera and 1,157 species. Software format Data are supplied as a comma‐delimited text file (.csv).
The Earth has undergone numerous geological and biological changes over billions of years. The evolution of plants and animals had a direct relationship with the elements’ changes in the atmosphere and the development of the biogeochemical cycles on Earth. The Anthropocene is the age of the Homo sapiens leaves its geological signature on the planet. Human domination and/or interference in the biogeochemical cycles results in an environmental change that affects not only ecosystems, in general, but also the biota and global biodiversity. In this way, we are creating another mass extinction event, the “sixth extinction wave” as well as transforming the ecosystems’ functions and services.
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