Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and meta-analyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging from -9 to +26 °C MAT and from 60 to 3113 mm MAP) across different ecosystems. In this study we tested the effect of climate (temperature and moisture), litter type and land-use on early stage decomposition (3 months) across nine biomes. We show that litter quality was the predominant controlling factor in early stage litter decomposition, which explained about 65% of the variability in litter decomposition at a global scale. The effect of climate, on the other hand, was not litter specific and explained <0.5% of the variation for Green tea and 5% for Rooibos tea, and was of significance only under unfavorable decomposition conditions (i.e. xeric versus mesic environments). When the data were aggregated at the biome scale, climate played a significant role on decomposition of both litter types (explaining 64% of the variation for Green tea and 72% for Rooibos tea). No significant effect of land-use on early stage litter decomposition was noted within the temperate biome. Our results indicate that multiple drivers are affecting early stage litter mass loss with litter quality being dominant. In order to be able to quantify the relative importance of the different drivers over time, long-term studies combined with experimental trials are needed.
Building bridges between environmental and political agendas is essential nowadays in face of the increasing human pressure on natural environments, including wetlands. Wetlands provide critical ecosystem services for humanity and can generate a considerable direct or indirect income to the local communities. To meet many of the sustainable development goals, we need to move our trajectory from the current environmental destructive development to a wiser wetland use. The current article contain a proposed agenda for the Pantanal aiming the improvement of public policy for conservation in the Pantanal, one of the largest, most diverse, and continuous inland wetland in the world. We suggest and discuss a list of 11 essential interfaces between science, policy, and development in region linked to the proposed agenda. We believe that a functional science network can booster the collaborative capability to generate creative ideas and solutions to address the big challenges faced by the Pantanal wetland.
Competition plays a central role in the maintenance of biodiversity. A backbone of classic niche theory is that local coexistence of competitors is favoured by the contraction or divergence of species' niches. However, this effect should depend on the diversity of resources available in the local environment, particularly when resources vary in multiple ecological dimensions. Here, we investigated how available resource breadth (i.e. prey diversity) and competition together shape multidimensional niche variation (between and within individuals) and interspecific niche overlap in 42 populations of congeneric tropical frog species. We modelled realized niches in two key trophic dimensions (prey size and carbon stable isotopes) and sampled available food resources to quantify two-dimensional resource breadth. We found a 14-fold variation in multidimensional population niche width across populations, most of which was accounted for by within-individual diet variation. This striking variation was predicted by an interaction whereby individual niche breadth increased with resource breadth and decreased with the number of congeneric competitors. These ecological gradients also interact to influence the degree of niche overlap between species, which surprisingly decreased with population total niche width, providing novel insights on how similar species can coexist in local communities. Together, our results emphasize that patterns of exploitation of resources in multiple dimensions are driven by both competitive interactions and extrinsic factors such as local resource breadth.
Although neglected by classic niche theory, individual variation is now recognized as a prevalent phenomenon in nature with evolutionary and ecological relevance. Recent theory suggests that differences in individual variation across competitors can affect species coexistence and community patterns. However, the degree of individual variation is flexible across wild populations and we still know little about the ecological drivers of this variation across populations of single species and, especially, across coexisting species. Here, we aimed to (a) elucidate the major drivers of individual niche variation in natural communities and (b) to determine how consistent this variation is across coexisting species and communities. We analysed natural patterns of individual-level niche variation in four species of coexisting generalist frogs across a wide range of tropical communities. Specifically, we used gut contents and stable isotopes (δ C and δ N) from frog species and their prey to quantify individual niche specialization. Then, we combined data on local community structure, availability of prey, phylogenetic relationships and predator-prey size models to test how this variation is related to four ecological factors which are predicted to be key drivers of individual specialization: intraspecific competition, interspecific competition, ecological opportunity (i.e., diversity of resources) and predation. We found that the degree of individual trophic specialization varied by up to ninefold across populations within the same species. This sizable variation in trophic specialization across populations was at least partially explained by gradients of density of competitors (both conspecifics and heterospecifics) and intraguild predation. However, the specific relationships between individual specialization and these ecological gradients were strongly species-specific. As consequences, the identity of the species with more individual variation changed among sites and there was typically no spatial correlation in the degree of individual specialization across coexisting species. Our results show that individual niche specialization within and across species can be strongly context-dependent and that hierarchies of individual variation among coexisting species are not necessarily consistent across communities. Recent theory suggests that this pattern could lead to concurrent changes in competitive interactions across sites and thereby could play a key role in species coexistence at the landscape level. Our results suggest that individual variation across and within coexisting species has the potential to affect not only species coexistence at local communities, but also regional diversity patterns.
Among the physiographic regions included in the central South American diagonal of open formations, the Chaco, with some endemic species, represents the southernmost dry area. In Brazil, the Chaco is found in southwestern corner of Mato Grosso do Sul state, mostly in the municipality of Porto Murtinho along the Paraguay and Apa rivers. From February 2008 to December 2009, we carried out an inventory of amphibians and reptiles in Porto Murtinho, using pitfall traps, time-limited searches, and occasional encounters. A total of 34 amphibian and 39 reptile species were registered. Although some typical Chacoan species were found, most of the species are open area dwellers that also occur in other open biomes, such as the Cerrado and Caatinga.
ABSTRACT. Amphibian diversity of Mato Grosso do Sul State, Brazil. Amphibian species from Mato Grosso do Sul state were compiled and checked for the fi rst time. A total of 97 species were recorded, representing more than 10% of the known Brazilian amphibians. Twenty fi ve anuran genera in nine families and only one caecilian were recorded. Cerrado was the richest area followed by semideciduous forests, Chaco, and veredas (palm swamps). It was recorded 56 species in fl oodplain areas and 92 in the surrounding cerrados. The Serra da Bodoquena National Park and some Pantanal areas were better sampled than other regions in Mato Grosso do Sul, resulting in sampling gaps across the state. Important areas for future inventories were identifi ed: mountainous regions in Serra de Maracaju and those bordering the Apa river, Brazilian chacoan areas, the Taquari river alluvial fan, the broad Taquari-Itiquira fl at area, the Central Plateau scarps, wet areas from Parana river bordering São Paulo state, and inland areas from Pantanal.KEYWORDS. Amphibia, inventories, biodiversity, Biota-MS Program.RESUMO. A fauna de anfíbios do estado de Mato Grosso do Sul foi compilada e elaborada pela primeira vez, totalizando 97 espécies, o que representa pouco mais de 10% das espécies que ocorrem no Brasil. Nove famílias e 25 gêneros de Anura e apenas uma espécie de Gymnophiona foram registradas. As áreas de Cerrado apresentaram a maior riqueza, seguidas pelas fl orestas estacionais semideciduais, Chaco e veredas. Em relação às macrorregiões consideradas, foram registradas 56 espécies para a planície de inundação (majoritariamente representada pelo Pantanal) e 92 para o planalto. As regiões mais amostradas em Mato Grosso do Sul são o Parque Nacional da Serra da Bodoquena e algumas áreas do Pantanal, o que resulta em lacunas de amostragens por todo o estado, principalmente nas regiões norte, leste/sudeste e parte do oeste/sudoeste. Foram identifi cadas áreas consideradas importantes para amostragens em decorrência da complexidade de fi tofi sionomias e relevos encontrados no estado: Maciço do rio Apa, Serra de Maracaju, grande parte do Chaco brasileiro, leque do rio Taquari, planalto do Taquari-Itiquira, escarpas do planalto Central, áreas úmidas/fl orestas estacionais da planície do rio Paraná e áreas interioranas do Pantanal, onde o acesso é difícil.
Variation in fitness across individuals is central to population growth, species coexistence and evolution by natural selection. Fitness variation associated with resource use is hugely consequential, but how this variation is generated and maintained within natural populations remains unclear. In particular, individual fitness may depend on many cumulative foraging decisions over time, but this hypothesis remains untested. We used multi‐tissue stable isotope analysis to determine isotopic niche trajectories within species, populations and sexes of thin‐toed frogs and explored how this temporal dimension of diet affects individual reproductive investment, body condition and parasite load. We found that individual frogs shifted their diets less than expected under a null model, likely due to functional trade‐offs that limit the incorporation of new prey types over time. However, within the observed range of diet shifts, individuals that modified their diet to a greater degree exhibited higher fitness, although this effect was sex‐dependent. We suggest that these different relationships between isotopic niche trajectory length and fitness within thin‐toed frogs are driven by variability in the resource environment, negative density dependence and allometric constraints. These strong fitness effects suggest that the temporal dimension of diet change is a potential target of natural selection and, therefore, could drive correlated evolution in phenotypic traits underlying diet flexibility. Our findings add a new level of complexity to the understanding of ecological and evolutionary consequences of niche variation by demonstrating that temporal variation in foraging consistency within populations leads to different fitness pay‐offs. A free Plain Language Summary can be found within the Supporting Information of this article.
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