We performed bimonthly mosquito larval collections during 1 year, in an agricultural settlement in the Brazilian Amazon, as well as an analysis of malaria incidence in neighboring houses. Water ...collections located at forest fringes were more commonly positive for Anopheles darlingi larvae and Kulldorff spatial analysis pinpointed significant larval clusters at sites directly beneath forest fringes, which were called larval "hotspots." Remote sensing identified 43 "potential" hotspots. Sampling of these areas revealed an 85.7% positivity rate for A. darlingi larvae. Malaria was correlated with shorter distances to potential hotpots and settlers living within 400 m of potential hotspots had a 2.60 higher risk of malaria. Recently arrived settlers, usually located closer to the tip of the triangularly shaped deforestation imprints of side roads, may be more exposed to malaria due to their proximity to the forest fringe. As deforestation progresses, transmission decreases. However, forest remnants inside deforested areas conferred an increased risk of malaria. We propose a model for explaining frontier malaria in the Amazon: because of adaptation of A. darlingi to the forest fringe ecotone, humans are exposed to an increased transmission risk when in proximity to these areas, especially when small dams are created on naturally running water collections.
Land use intensification drives biodiversity loss worldwide. In heterogeneous landscape mosaics, both overall forest area and anthropogenic matrix structure induce changes in biological communities ...in primary habitat remnants. However, community changes via cross‐habitat spillover processes along forest–matrix interfaces remain poorly understood. Moreover, information on how landscape attributes affect spillover processes across habitat boundaries are embryonic. Here, we quantify avian α‐ and β‐diversity (as proxies of spillover rates) across two dominant types of forest–matrix interfaces (forest–pasture and forest–eucalyptus plantation) within the Atlantic Forest biodiversity hotspot in southeast Brazil. We also assess the effects of anthropogenic matrix type and landscape attributes (forest cover, edge density and land‐use diversity) on bird taxonomic and functional β‐diversity across forest–matrix boundaries. Alpha taxonomic richness was higher in forest edges than within both matrix types, but between matrix types, it was higher in pastures than in eucalyptus plantations. Although significantly higher in forests edges than in the adjacent eucalyptus, bird functional richness did not differ between forest edges and adjacent pastures. Community changes (β‐diversity) related to species and functional replacements (turnover component) were higher across forest–pasture boundaries, whereas changes related to species and functional loss (nested component) were higher across forest–eucalyptus boundaries. Forest edges adjacent to eucalyptus had significant higher species and functional replacements than forest edges adjacent to pastures. Forest cover negatively influenced functional β‐diversity across both forest–pasture and forest–eucalyptus interfaces. We show the importance of matrix type and the structure of surrounding landscapes (mainly forest cover) on rates of bird assemblage spillover across forest‐matrix boundaries, which has profound implications to biological fluxes, ecosystem functioning and land‐use management in human‐modified landscapes.
Context
The ecological interplay between edge and matrix effects along forest-matrix interfaces is closed linked to landscape processes modulating biodiversity and ecosystem services provision in ...disturbed landscapes. Improving such knowledge is therefore essential to design more efficient land use management in multifunctional landscapes.
Objectives
Estimate the avian-mediated Ecosystem Service Provision (ESP) in contrasting types of forest-matrix interfaces in tropical landscapes, and examine how local habitat and landscape attributes can predict ESPs.
Methods
We sampled bird assemblages in forest-pasture (FP) and forest-eucalyptus plantation (FE) interfaces, and estimated their potential as pest control, seed dispersal and pollination agents across human-modified landscapes in southeastern Brazil. Using Random Forest algorithm, we also quantified the relative importance of local vs. landscape attributes in predicting ESPs.
Results
The overall ESPs was higher in FP than FE interfaces. Habitat generalist birds were important potential seed disperser and pollinator agents at both FP and FE. At forest edges, landscape forest cover best predicted pest control services, whereas the density of rural homesteads best predicted potential seed dispersal and pollination services. Local habitat features were particularly important in predicting all ESP in pastures.
Conclusions
We highlight the importance of matrix type and matrix habitat structure in modulating avian ESPs across forest-matrix interfaces in human-altered landscapes and suggest that forest cover and rural homestead density are key elements in multifunctional landscapes that consider avian ESP in both forest and matrix habitats.
Pleurothallidinae orchids have been the focus of many multidisciplinary studies due to their challenging systematics and taxonomy. The synapomorphies already recognized in the group are mostly ...related to floral characters, the last proposed being the occurrence of alkanes in the floral fragrance. The composition of the floral bouquet varied significantly among the studied species, leading us to hypothesize that the variations in volatiles emitted could be linked to the structure of osmophores, especially when comparing the myophilous and sapromyophilous pollination syndromes. Sepals and labellum at different developmental stages of seven Brazilian Pleurothallidinae species were examined using light, scanning, and transmission electron microscopy. Nectar reabsorption was assessed by Lucifer Yellow CH tracer and imaged under confocal microscopy. Nectaries were restricted to the labellum of the myophilous species, whereas osmophores occurred in the dorsal and/or lateral sepals, varying according to species. In the sapromyophilous species, floral nectaries were not detected and osmophores were restricted to the labellum. Osmophore structure was correlated with the volatiles emitted, being the trichome osmophores notably present on the sepals of both myophilous species that possess nectaries. For the first time, we demonstrated reabsorption of the released nectar in Pleurothallidinae and the occurrence of a unique gland named sticky-exudate glands, which occurred in the lateral sepals and labellum of
Echinosepala aspasicensis
, a sapromyophilous species, that released a heterogeneous exudate composed of polysaccharides and lipids. Similar glands have been reported in
Bulbophyllum
, highlighting the convergence between both groups.
Hypancistrus zebra is a Loricariid endemic to a very limited stretch of the Xingu River and has a high value in the ornamental fish trade. The natural populations have experienced high fishing ...pressure since the late 80s and were recently impacted by the construction of the third largest hydroelectric dam complex in the world, the Belo Monte Project. Since 2004, it has been considered critically endangered and had its capture and trade forbidden. Even with its capture and trade prohibited since 2004, the species continues to be one of the most trafficked fish in the world. The biometric knowledge of the species is essential for monitoring its natural populations and management in ex situ environments. This work aims to establish the weight-length relationship (WLR) and length-length relationship (LLR) of the species and to evaluate the condition factor (K) of H. zebra rescued from trafficking. The study was conducted at the Laboratório de Aquicultura de Peixes Ornamentais do Xingu from February 2022 to June 2022, estimating the parameters of WLR and LLR of 1165 specimens divided into four simple linear regression (SLR) models: all specimens, only juveniles, only females, and only males. The K of 190 specimens rescued from trafficking by the Brazilian Federal Police was evaluated. The WLRs and LLRs were estimated using SLR. The difference between the allometry coefficients (b) and between the residuals of the models (juveniles, females, and males) was evaluated using the ANOVA significance test. The total length of the species ranged from 1.6 to 9.3 cm. The coefficient of allometry (b) of the WLR of the species is 3.22 and of the LLR is 1.04, demonstrating that H. zebra presents positive allometric growth. The evaluation of the residuals of the models showed differences between ontogenetic stages and between sexes. The development of juveniles is isometric until the first sexual maturation phase and differs in negative allometric for females and positive allometric for males, showing sexual dimorphism in the species. Among the specimens rescued from trafficking, 54.74% were underweight, and 13.16% were under 60% of the expected K value, demonstrating the poor conditions in which these animals are transported by trafficking.
The entangled relationship of chromosome number and genome size with species distribution has been the subject of study for almost a century, but remains an open question due to previous ecological ...and phylogenetic knowledge constraints. To better address this subject, we used the clade Maxillariinae, a widely distributed and karyotypically known orchid group, as a model system to infer such relationships in a robust methodological framework.
Based on the literature and new data, we gathered the chromosome number and genome size for 93 and 64 species, respectively. We built a phylogenetic hypothesis and assessed the best macroevolutionary model for both genomic traits. Additionally, we collected together ecological data (preferences for bioclimatic variables, elevation and habit) used as explanatory variables in multivariate phylogenetic models explaining genomic traits. Finally, the impact of polyploidy was estimated by running the analyses with and without polyploids in the sample.
The association between genomic and ecological data varied depending on whether polyploids were considered or not. Without polyploids, chromosome number failed to present consistent associations with ecological variables. With polyploids, there was a tendency to waive epiphytism and colonize new habitats outside humid forests. The genome size showed association with ecological variables: without polyploids, genome increase was associated with flexible habits, with higher elevation and with drier summers; with polyploids, genome size increase was associated with colonizing drier environments.
The chromosome number and genome size variations, essential but neglected traits in the ecological niche, are shaped in the Maxillariinae by both neutral and adaptive evolution. Both genomic traits are partially correlated to bioclimatic variables and elevation, even when controlling for phylogenetic constraints. While polyploidy was associated with shifts in the environmental niche, the genome size emerges as a central trait in orchid evolution by the association between small genome size and epiphytism, a key innovation to Neotropical orchid diversification.
The intrinsic complexity, variety of concepts and numerous ways to quantify landscape heterogeneity (LH) may hamper a better understanding of how its components relate to ecological phenomena. Our ...study is the first to synthesize understanding of this concept and to provide the state of the art on the subject based on a comprehensive systematic literature review of 661 articles published between 1982 and 2019. Definitions, terminologies and measurements of LH were diverse and conflicting. Most articles (534 out of 661) did not provide any definition for LH, and we found great variation among the studies that did. According to our review, only 10 studies measured the effects of different land-cover types on biotic or abiotic processes (functional LH). The remaining 651 studies measured physical attributes of the landscape without mentioning that different land-cover types may impact biotic and abiotic processes differently (structural LH). The metrics most frequently used to represent LH were the Shannon diversity index and proportion of land-cover type. Most metrics used as proxies of LH also coincided with those used to represent non-heterogeneity metrics, such as fragmentation and connectivity. We identify knowledge gaps, indicate future perspectives and propose guidelines that should be addressed when researching LH.
The production of animal-based foods from native breeds have a synergistic relationship with the regional culture, the local climate, and mainly the maintenance of alternative genetic resources for a ...system with a lower environmental impact. Thus the efficiency of conservation and production depends on assessing the variability of these local breeds. In the case of Curraleiro Pé-duro cattle, the most adapted individuals have undergone natural selection over five hundred years in the Brazilian savannas, mating with little or no human interference. The peculiarities of these biomes, where the regional flora is the food base and cattle is raised in extensive areas, likely influenced the genetic composition of the different groups that make up the first cattle breed of Brazil.
To evaluate the composition, diversity, variation, differentiation, and genetic structure of the populations studied, samples of hair follicles from 474 individuals of different animal categories (calves, yearlings, heifers, cows, and bulls) from three farms, defined as subpopulations "A", "B", and "C", were collected. The animals were genotyped for 17 microsatellite markers using a DNA sequencer. After verification of monomorphic alleles, alleles outside the expected size range, and for the presence of stutter bands, the results were subjected to statistical analysis.
The markers used were suitable for the proposed application with a mean Polymorphism Information Content (PIC) of 0.62. On average, the effective alleles were 4.25 per marker, with mean heterozygosities of 0.74 (observed and expected), which was lower in herd A (0.70) in comparison to herds B (0.77) and C (0.74). The analysis of molecular variance (AMOVA) revealed a higher rate of variation within herds (98.5%) and lower among herds (1.5%) (F
ranging from 0.00723 and 0.03198;
-values < 0.05). However no significant differences among herds where found with the Mantel test based on geographic distances. The formation of genetic clusters of all animals sampled with the software Structure resulted in minimum cluster values, with two main genetic groups (
= 2) observed among the evaluated animals. Therefore, based on PIC and heterozygosity values, a wide genetic diversity was observed, despite little differences in population structure (AMOVA, F
, and Structure results) among sampling sites.
Phylogeographic studies provide an important framework for investigating the mechanisms operating during the earliest stages of speciation, as reproductive barriers can be examined among divergent ...lineages in a geographic context. We investigated the evolution of early stages of intrinsic postmating isolation among different populations and lineages of Epidendrum denticulatum, a Neotropical orchid distributed across different biomes in South America. We estimated genetic diversity and structure for both nuclear and plastid markers, using a haplotype network, differentiation tests, Bayesian assignment analysis, and divergence time estimates of the main lineages. Reproductive barriers among divergent lineages were examined by analyzing seed viability following reciprocal crossing experiments. Strong plastid phylogeographic structure was found, indicating that E. denticulatum was restricted to multiple refuges during South American forest expansion events. In contrast, significant phylogeographic structure was not found for nuclear markers, suggesting higher gene flow by pollen than by seeds. Large asymmetries in seed set were observed among different plastid genetic groups, suggesting the presence of polymorphic genic incompatibilities associated with cytonuclear interactions. Our results confirm the importance of phylogeographic studies associated with reproductive isolation experiments and suggest an important role for outbreeding depression during the early stages of lineage diversification.
Nickel (Ni)-a component of urease and hydrogenase-was the latest nutrient to be recognized as an essential element for plants. However, to date there are no records of Ni deficiency for annual ...species cultivated under field conditions, possibly because of the non-appearance of obvious and distinctive symptoms, i.e., a hidden (or latent) deficiency. Soybean, a crop cultivated on soils poor in extractable Ni, has a high dependence on biological nitrogen fixation (BNF), in which Ni plays a key role. Thus, we hypothesized that Ni fertilization in soybean genotypes results in a better nitrogen physiological function and in higher grain production due to the hidden deficiency of this micronutrient. To verify this hypothesis, two simultaneous experiments were carried out, under greenhouse and field conditions, with Ni supply of 0.0 or 0.5 mg of Ni kg
of soil. For this, we used 15 soybean genotypes and two soybean isogenic lines (urease positive,
; urease activity-null,
, formerly
). Plants were evaluated for yield, Ni and N concentration, photosynthesis, and N metabolism. Nickel fertilization resulted in greater grain yield in some genotypes, indicating the hidden deficiency of Ni in both conditions. Yield gains of up to 2.9 g per plant in greenhouse and up to 1,502 kg ha
in field conditions were associated with a promoted N metabolism, namely, leaf N concentration, ammonia, ureides, urea, and urease activity, which separated the genotypes into groups of Ni responsiveness. Nickel supply also positively affected photosynthesis in the genotypes, never causing detrimental effects, except for the
mutant, which due to the absence of ureolytic activity accumulated excess urea in leaves and had reduced yield. In summary, the effect of Ni on the plants was positive and the extent of this effect was controlled by genotype-environment interaction. The application of 0.5 mg kg
of Ni resulted in safe levels of this element in grains for human health consumption. Including Ni applications in fertilization programs may provide significant yield benefits in soybean production on low Ni soil. This might also be the case for other annual crops, especially legumes.
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