Brazilian Pampa Biome Research Articles

Sustainability in the Brazilian pampa biome: A composite index to integrate beef production, social equity, and ecosystem conservation

The natural grasslands of the Pampa biome (PB) are maintained by moderate grazing of large ruminants that traditionally occupy the area, offering a place where food production and natural habitat conservation may coexist. The conversion of natural grasslands (NG) into other land covers, and the consequent modifications of natural landscapes, highlights the need for better management strategies to maintain grasslands in good natural conditions. However, there are many factors that influence sustainability, and to understand the reality of each location and its needs to achieve a sustainable status are a challenge for public managers and for entrepreneurs. Therefore, it is important to evaluate where sustainable beef production is more indicated and which criteria demands more attention for a better sustainable scenario. Hence, this study proposed a composite index to evaluate areas of tension based on the concepts of sustainability and efficient beef cattle farming for NG in the Brazilian PB. The Sustainable Tension Index (STI) is a composite index of descriptor variables that represent the economic, social, and environmental dimensions. The selection of this variables was based on a literature review and governmental documents. For each variable a weight was calculated by a principal components analysis. Each standardized variable was multiplied by the value of its weight, and the results were summed for each municipality to obtain the STI. The STI was classified into intervals by dividing the amplitude of the values by five from very low to very high tensions. Municipalities with low tensions across the three dimensions were considered closer to sustainable development. To evaluate the differences among mesoregions, a PERMANOVA was applied in R software. The STI was able to describe the localities regarding sustainable beef production variables and identified the critical factors in each municipality. Most of Pampa's municipalities presented intermediaries STI, but only three presented low tension in all the dimension, emphasizing the complexity of this issue. The southwest and southeast mesoregions were more apt to sustainable beef production, and the metropolitan mesoregion was the least indicated for this activity. Variables associated to education, income and land use had higher weight for the index. The proposed STI is a tool for both farm managers and political representants to support important decisions and its application presented an optimistic reality regarding the Brazilian PB, which if well managed and supported, has a great potential for sustainable beef cattle farming.

Population analysis of white grubs (Coleoptera: Melolonthidae) throughout the Brazilian Pampa biome

The replacement of natural grassland by cultivated areas might favor the increase in abundance of some root-feeding species such as the white grubs, which may become a constraint for field crop production. This research aimed to assay the population density and geographical distribution of white grubs pest and other species in natural grassland and cultivated areas throughout the Brazilian Pampa biome. White grubs were sampled in 18 locations in both landscape use types and identified. Population density (number of larvaem−2) was calculated for each recorded species and sorted within two groups (pest species and other species), compared between natural grasslands and cultivated areas, as well as among locations. A dendrogram to evaluate species similarity among locations was built based on combined data obtained from both landscape use types throughout the region. In total, 31 species were found in the Brazilian Pampa, and four of them are considered as crop pests: Diloboderus abderus (Sturm, 1826), Euetheola humilis (Burmeister, 1847), Lyogenys fusca (Blanchard, 1830), and Phyllophaga triticophaga Morón & Salvadori, 1998. The average population density of pest species in cultivated areas was less than five larvae m−2, at most of locations. Some species had a wide geographical distribution (e.g. D. abderus and Cyclocephala modesta Burmeister), while other melolontids occurred at only one location. The knowledge of which white grub species are present in a field and its population densities assist farmers to take proper management decisions.

Abundance and Diversity in the Melolonthidae Community in Cultivated and Natural Grassland Areas of the Brazilian Pampa.

Annual crops or exotic trees for cellulose extraction have replaced natural grassland areas of the Brazilian Pampa biome. These activities have been intensified in recent years and may lead to changes in the white grub complex. The objective of this study was to characterize the diversity and abundance of white grubs in cultivated and natural grassland areas of the Brazilian Pampa biome. We conducted samplings in natural grassland and cultivated areas throughout 18 locations in the Brazilian Pampa. Diversity index and nonmetric multidimensional scaling (NMDS) were used to compare the Melolonthidae community within and between cultivated and natural grassland areas. Diloboderus abderus Sturm, Cyclocephala modesta Burmeister, and Plectris sp.5 (Coleoptera: Melolonthidae) were the most abundant taxa, accounting for 49.08% of all white grubs collected from both land use types. Abundance, diversity, and evenness indices were greater in natural grassland than in cultivated areas. The NMDS demonstrated that natural grassland and cultivated areas share similar white grub species assemblages, with 22 species collected in both land use types. Our data suggest that most of the Melolonthidae species collected in the Brazilian Pampa are capable of persisting in cultivated areas. This is the first work characterizing the Melolonthidae community throughout the Brazilian Pampa, which is vital for implementing pest management tactics and conservation of beneficial species.

Honey protects against wings posture error and molecular changes related to mitochondrial pathways induced by hypoxia/reoxygenation in adult Drosophila melanogaster

We conducted an investigation to evaluate the effects of Brazilian Pampa biome honey and its major phenolic compounds on the development of an erected wings posture phenotype and related mitochondrial aspects induced by Hypoxia/Reoxygenation (H/R) in Drosophila melanogaster. Flies were pre-treated for 3 days with a 10% honey solution and different concentrations of caffeic acid and ρ-coumaric acid and then submitted to hypoxia for 3 h. We observed that after reoxygenation, some flies acquired an erected wings posture and that this feature may be related to mortality. In addition, H/R induced down-regulation of ewg mRNA expression, which could be associated to the observed complex phenotype. H/R also caused a dysregulation in opa1-like, ldh and diap genes expression and reduced O2 fluxes in flie's mitochondria. Honey mitigated opa1-like mRNA expression changes provoked by H/R. Differently from honey, caffeic and ρ-coumaric acids displayed no protective effects. In conclusion, we report for the first time the protective effects of honey against complex phenotypes and mitochondrial changes induced by H/R in adult flies.

Co-invasion of ectomycorrhizal fungi in the Brazilian Pampa biome

The introduction of ectomycorrhizal fungi along with the introduced ectomycorrhizal plants is rarely considered at the ecosystem level. In Brazil, the Pampa biome is the dominant ecosystem in the Rio Grande do Sul State, predominantly with pastoral management but intensively planted with non-native trees over the last century. Sporocarps of ectomycorrhizal and putative ectomycorrhizal fungi were collected in Pampa biome native forest vegetation and plantation forests during the period 2009–2013, with an emphasis on plantations of eucalypts and pines. Morphological analysis and molecular markers were used to identify collected sporocarps. A total of 60 different taxa were collected, mainly fitting into Australasian ectomycorrhizal fungi lineages. Among collections, two turned out to be saprotrophic species from Amanita belonging to the subsect. Vittadiniae. The ectomycorrhizal fungi reported here showed that some co-introduced lineages are frequent co-invaders in the Brazilian Pampa biome with alien ectomycorrhizal trees, especially /descolea, /hysterangium, /laccaria, /pisolithus-scleroderma lineages. No ectomycorrhizal sporocarps were found in either plantation forest or in native forest sites and no novel associations were observed between native ectomycorrhizal fungal species and introduced plants. All ectomycorrhizal fungi co-introduced in the Brazilian Pampa were recorded with plant species of Australian or North American origin. The study has raised additional questions regarding the distribution, ecology and taxonomy of fungi from the Brazilian Pampa biome.

Fusarium fujikuroi : A novel source of metabolites with herbicidal activity

Abstract This study presents the isolation and identification of a fungus (Fusarium fujikuroi) from the Brazilian Pampa biome that is able to produce phytotoxic secondary metabolites with herbicidal activity. Before selecting such promising fungus, 132 microorganisms were isolated from weed plants with infections symptoms. Each sample of isolated material was used in submerged fermentation to produce a fermented broth. Thereafter, the cells were separated by centrifugation and the supernatant was filtered. Each filtered sample (culture filtrate) was used to evaluate the herbicidal activity in the bioassays with two target plants: Cucumis sativus and Sorghum bicolor. The selection criteria consisted of analyzing germination in pre-emergence, phytotoxicity, plant height and root length in post-emergence, and lesions in detached leaf-punctured assay. The pre-emergence was the primary screening, where 11 samples of culture filtrate provided 100% inhibition of germination of both plants. These samples underwent a secondary screening, which the sample SO210 presented 25% phytotoxicity, 40% reduction of plant height, 28% reduction of root length, and necrosis and chlorosis in 70% of foliar area. The microorganism coded as SO210 was identified as a strain of Fusarium fujikuroi. Up to now, studies that attribute herbicidal activity to this fungus are scarce in the literature. Therefore, this work shows a potential activity of metabolites produced by this fungus toward the inhibition of germination and development of plant weeds.

Agricultural land use change in the Brazilian Pampa Biome: The reduction of natural grasslands

This manuscript analyzes the land use changes and its conjectural drivers in the Brazilian Pampa Biome. Therefore, land use changes in the municipalities of this biome were collected from the Brazilian Agricultural Censuses of 1975, 1985, 1995/1996 and 2006. To analyze the changes in the land use for natural pastures, pampa’s microregions were compared in 10-year by a relative growth rate. There has been a 26% decrease in natural pastures in the Brazilian Pampa Biome since 1975, with a negative growth of −12.5% between 1975 and 1985. The activities with the highest growth were cultivated forests and temporary crops (1985–2005), and the increment of the area dedicated for those agricultural activities was related to the decrease in the area of natural pastures in the Pampa. Temporary crops (soy) and cultivated forests (forestry) began to integrate Pampa’s landscape mainly between 1995 and 2005, changing the native configuration of the biome. Finally, sharing information on the Brazilian Pampa Biome phenomena will facilitate future dialogue among all stakeholders, and this manuscript is expected to contribute to the global debate on the conservation of natural landscapes, especially natural grasslands.

Selection, isolation, and identification of fungi for bioherbicide production.

Production of a bioherbicide for biological control of weeds requires a series of steps, from selection of a suitable microbial strain to final formulation. Thus, this study aimed to select fungi for production of secondary metabolites with herbicidal activity using biological resources of the Brazilian Pampa biome. Phytopathogenic fungi were isolated from infected tissues of weeds in the Pampa biome. A liquid synthetic culture medium was used for production of metabolites. The phytotoxicity of fungal metabolites was assessed via biological tests using the plant Cucumis sativus L., and the most promising strain was identified by molecular analysis. Thirty-nine fungi were isolated, and 28 presented some phytotoxic symptoms against the target plant. Fungus VP51 belonging to the genus Diaporthe showed the most pronounced herbicidal activity. The Brazilian Pampa biome is a potential resource for the development of new and sustainable chemical compounds for modern agriculture.

Simulating the selfing and migration of Luehea divaricata populations in the Pampa biome to investigate the conservation potential of their genetic resources.

Computer simulations are an important tool for developing conservation strategies for forest species. This study used simulations to investigate the genetic, ecological, and reproductive patterns that contribute to the genetic structure of the tree Luehea divaricata Mart. & Zucc. in five forest fragments in the Brazilian Pampa biome. Using the EASYPOP model, we determined the selfing and migration rates that would match the corresponding genetic structure of microsatellite marker data (based on observed and expected heterozygosity parameters). The simulated reproductive mode was mixed, with a high rate of outcrossing (rate = 0.7). This was consistent with a selfing-incompatible system in this species, which reduced, but did not prevent, selfing. The simulated migration rate was 0.02, which implied that the forest fragments were isolated by distance, and that the inbreeding coefficients were high. Based on Nei's gene diversity analysis, 94% of the genetic variability was distributed within the forest fragments, and only 6% of the genetic diversity was caused by differences between them. Furthermore, the minimum viable population and minimum viable area genetic conservation parameters (which determine conservation potential in the short and long term) suggested that only the Inhatinhum forest fragment had the short-term potential to maintain its genetic diversity. However, in the long term, none of the forest fragments proved to be sustainable, indicating that the populations will require intervention to prevent a decline in genetic variability. The creation of ecological corridors could be a useful solution to connect forest fragments and enhance gene flow between them.

APPLICATION OF FISHER’S DISCRIMINANT ANALYSIS TO CLASSIFY FOREST COMMUNITIES IN THE PAMPA BIOME

http://dx.doi.org/10.5902/1980509820587Fisher Discriminant Analysis (DA) seeks a linear combination of independent variables maximizing separation of predicted groups and also permits new observations for being classified in groups know a priori. We applied DA with eight structural attributes of vegetation obtained of systematic tree inventory surveys realized in five physiognomies types in the Brazilian Pampa biome. Later, 10 new samples were randomly selected from the same vegetation types to perform model validation. The DA generated four discriminant functions (DFs), where the first two had 88.4% power for discriminating groups (DF1 = 74.4% and DF2 = 14%). From the structural attributes used in the model, species richness, commercial height, and total height were related to DF1. Basal area and maximum stem diameter were related to DF2. The others DFs and structural variables have had less power of discriminating the groups. The DA classified 100% of the cases in their respective groups, showing a high efficiency of the chosen discriminating variables. The new forest samples inserted in the model were also classified with a small degree of error. The use of DA models should be enhanced because it is simple and more effective to express a forest classification model than the other descriptive multivariate methods.

Brazilian Pampa Biome Honey Protects Against Mortality, Locomotor Deficits and Oxidative Stress Induced by Hypoxia/Reperfusion in Adult Drosophila melanogaster.

We aimed to investigate the potential beneficial effects of the Brazilian Pampa biome honey in a Drosophila-based hypoxia model. Adult flies were reared in standard medium in the presence or absence of honey (at a final concentration of 10 % in medium). Then, control flies (4 % sucrose in medium) and honey-treated flies were submitted to hypoxia. Subsequently, flies were analyzed for mortality, neurolocomotor behavior (negative geotaxis), mitochondrial/oxidative stress parameters and expression of hypoxia/stress related genes by RT-qPCR. The HPLC analysis revealed the presence of phenolics and flavonoids in the studied honey. Caffeic acid was the major compound followed by p-coumaric acid and kaempferol. The presence of such compounds was correlated with a substantial antioxidant activity in vitro. Flies subjected to hypoxia presented marked mortality, locomotor deficits and changes in oxidative stress and mitochondrial activity parameters. Honey treatment was able to completely block mortality and locomotor phenotypes. In addition, honey was able to reverse ROS production and hypoxia-induced changes in mitochondrial complex I and II activity. Hypoxia also induced an up-regulation in mRNA expression of Sima (HIF-1), NFκβ, NRF2, HOX, AKT-1, InR, dILP2, dILP5 and HSP27. Honey treatment was not able to modulate changes in the tested genes, indicating that its protective effects involve additional mechanisms other than transcriptional activity of hypoxia-driven adaptive responses in flies. Our results demonstrated, for the first time, the beneficial effects of honey against the deleterious effects of hypoxia/reperfusion processes in a complex organism.

Bioherbicide production by Diaporthe sp. isolated from the Brazilian Pampa biome

Abstract In this study was presented a rational strategy to scale-up a wild fungal strain from the Brazilian Pampa biome to produce compounds with herbicidal activity in pre-emergence. It was defined the medium composition for the growth and production of bioherbicide in shaken flasks using sucrose corn steep liquor as substrate. In a second step, the process variables in a stirred-tank bioreactor were assessed. Maximum biomass production in shaken flasks was 23.87 g L −1 (41% higher than synthetic media) and in the bioreator 27.8 g L −1 . The Diaporthe sp. growth in bioreactor was negatively affected by agitation higher than 40 rpm. The bioherbicide efficiency rate reached 100%, since none seed germinated after the application of fermented broth. The Brazilian Pampa biome could be an effective way to obtain high-value products from the biodiversity.

Assessment of water pollution in the Brazilian Pampa biome by means of stress biomarkers in tadpoles of the leaf frog Phyllomedusa iheringii (Anura: Hylidae).

The Brazilian Pampa biome is currently under constant threat due to increase of agriculture and improper management of urban effluents. Studies with a focus on the assessment of impacts caused by human activities in this biome are scarce. In the present study, we measured stress-related biomarkers in tadpoles of the leaf frog Phyllomedusa iheringii, an endemic species to the Pampa biome, and tested its suitability as a bioindicator for the assessment of potential aquatic contamination in selected ponds (S1 and S2) nearby agricultural areas in comparison to a reference site. A significant decrease in acetylcholinesterase activity was observed in S2 when compared to S1 and reference. The levels of total-hydroperoxides were increased in S2 site. In parallel, increased activity of the antioxidant enzymes catalase, superoxide dismutase and glutathione S-transferase were observed in S2 when compared to S1 and reference. Further studies are necessary in order to correlate the changes observed here with different chemical stressors in water, as well as to elucidate mechanisms of toxicity induced by pesticides in amphibian species endemic to the Pampa biome. Nevertheless, our study validates Phyllomedusa iheringii as a valuable bioindicator in environmental studies.

Oxidative stress markers in fish (Astyanax sp. and Danio rerio) exposed to urban and agricultural effluents in the Brazilian Pampa biome.

Aquatic ecosystems are under constant risk due to industrial, agricultural, and urban activities, compromising water quality and preservation of aquatic biota. The assessment of toxicological impacts caused by pollutants to aquatic environment using biomarker measurements in fish can provide reliable data to estimate sublethal effects posed by chemicals in contaminated areas. In this study, fish (Astyanax sp. and Danio rerio) exposed to agricultural and urban effluents at the Vacacaí River, Brazil, were tested for potential signs of aquatic contamination. This river comprehends one of the main watercourses of the Brazilian Pampa, a biome with a large biodiversity that has been neglected in terms of environmental and social-economic development. Sites S1 and S2 were chosen by their proximity to crops and wastewater discharge points, while reference site was located upstream of S1 and S2, in an apparently non-degraded area. Fish muscle and brain tissues were processed for determination of acetylcholinesterase as well as oxidative stress-related biomarkers. The results showed signs of environmental contamination, hallmarked by significant changes in cholinesterase activity, expression of metallothionein, antioxidant enzymes, glutathione levels, and activation of antioxidant/cell stress response signaling pathways in fish exposed to contaminated sites when compared to reference. Based on these results, it is evidenced that urban and agricultural activities are posing risk to the environmental quality of water resources at the studied area. It is also demonstrated that cell stress biomarkers may serve as important tools for biomonitoring and development of risk assessment protocols in the Pampa biome.

Assessment of Water Pollution Signs in the Brazilian Pampa Biome Using Stress Biomarkers in Fish (Astyanax sp.)

Located in southern Brazil, the Pampa biome has been under constant threat due to improper management of human effluents and use of pesticides. These contaminants accumulate mainly in water resources resulting in chronic poisoning of aquatic biota. Up to date, no studies on the assessment of environmental quality in the Brazilian portion of Pampa biome have been undertaken. Thereby, our main goal in this study was to investigate the ecotoxicological risks caused by human activity in the Santa Maria River, a major water course in the Brazilian Pampa biome. Brain and muscle tissues were used for determining oxidative stress and cholinesterase biomarkers in fish (Astyanax sp.) exposed to urban and agricultural effluents. A substantial decrease in fish muscle acetylcholinesterase activity was observed in exposed animals, compared to controls (kept under laboratory conditions). In parallel, increased lipid peroxidation and significant changes in stress-responsive antioxidant enzymes (GST, CAT, GPx, and TrxR) were detected. In the fish brain, a significant increase in GST activity is reported. In conclusion, our results showed significant changes in biomarkers of water contamination in Astyanax captured in Santa Maria River, pointing to important levels of water pollution in the region and validating the use of Astyanax in biomonitoring programs within the Pampa biome borders.

Modeling distribution of Schinus molle L. in the Brazilian Pampa: insights on vegetation dynamics and conservation of the biome

Natural establishment of forests in the Brazilian Pampa biome should occur due to soil, hydrology and climate conditions, although no significant forest expansion over grassland has been noticed, precluded mainly by human interference and lack of environmental management. In this study, we used niche-modeling distribution of the tree species Schinus molle L. based on climatic variables to access the vegetation dynamics of the Brazilian Pampa and to develop strategies that assure the conservation of this biome, concerning both grassland and forest formations. Here we show that a large area of the Brazilian Pampa is suitable for expansion of S. molle populations, supporting the forest expansion over grassland as a natural process in this biome. We propose that the current absence of tree species expansion over the grassland in these areas is a result of the resilience of the grassland and of human interferences through expansion of agriculture, ranching and forestry with exotic species. Therefore, conservationist actions should focus on establishing preservation unities that include forest populations and grassland, while environmental management should be applied just in farming areas with historical human interference. Such actions will respect the ecological dynamics of the Pampa and value the forest formations in this grassland-dominated environment.

A Study on the Quality and Identity of Brazilian Pampa Biome Honey: Evidences for Its Beneficial Effects against Oxidative Stress and Hyperglycemia.

We characterized, for the first time, the quality and identity of Brazilian Pampa biome honey and its antioxidant properties in vitro (FRAP, DDPH and ABTS). The potential protective effect of honey against oxidative stress induced by iron (Fe) and paraquat, (PQ) in a Drosophila melanogaster model (in vivo) was also tested. The results indicated that all honey samples tested showed antioxidant activity in vitro. Flies treated with honey showed increased lifespan and were protected against oxidative stress induced by Fe and PQ. Despite the high concentration of sugars in honey (approximately 70–80%), our results demonstrate a hypoglycemic-like effect of honey in Drosophila. Thus, this study demonstrates the high quality of Brazilian Pampa biome honey as well as its significant antioxidant activity in vitro and in vivo, pointing to the potential use of this natural product as an alternative in the therapy of oxidative stress-associated diseases.

Land-use change and soil type are drivers of fungal and archaeal communities in the Pampa biome

The current study aimed to test the hypothesis that both land-use change and soil type are responsible for the major changes in the fungal and archaeal community structure and functioning of the soil microbial community in Brazilian Pampa biome. Soil samples were collected at sites with different land-uses (native grassland, native forest, Eucalyptus and Acacia plantation, soybean and watermelon field) and in a typical toposequence in Pampa biome formed by Paleudult, Albaqualf and alluvial soils. The structure of soil microbial community (archaeal and fungal) was evaluated by ribosomal intergenic spacer analysis and soil functional capabilities were measured by microbial biomass carbon and metabolic quotient. We detected different patterns in microbial community driven by land-use change and soil type, showing that both factors are significant drivers of fungal and archaeal community structure and biomass and microbial activity. Fungal community structure was more affected by land-use and archaeal community was more affected by soil type. Irrespective of the land-use or soil type, a large percentage of operational taxonomic unit were shared among the soils. We accepted the hypothesis that both land-use change and soil type are drivers of archaeal and fungal community structure and soil functional capabilities. Moreover, we also suggest the existence of a soil microbial core.