Brazilian Pampa Research Articles

Estimating natural grassland biomass by vegetation indices using Sentinel 2 remote sensing data

ABSTRACTEstimation of natural grassland biomass was carried out in a region located in the Brazilian Pampa, using field and remote sensing data and statistical models. The study was conducted in a grassland with a rotational grazing system, with grazing rest interval based on accumulated thermal sums 375 and 750 Degrees Day (DD). One image of the MSI (MultiSpectral Instrument) sensor aboard the Sentinel-2 satellite was evaluated and calibrated by 57 sampled biomass units collected in the field. Initially, the image was preprocessed, with extraction of the reflectance values of the Sentinel-2 bands, re-sampling of the pixels to 20 metres and calculation of vegetation indices. Data statistical analyses indicated significant correlations between field and remote sensing data. Multiple linear regression analyses were applied at each grazing rest interval using the remote sensing variables as predictors (independent) of the biomass (dependent). Among the variables, it is important to highlight the significant correlation of the red-edge bands with the biomass. The equations for estimating green biomass-presented coefficients of determination (R2) of R2 = 0.51 for the rest interval 375 DD and R2 = 0.65 for the rest interval 750 DD, while the senescent and total biomass generated adjustments with R2 ≤ 0.50 for the two rest intervals. Biomass estimates results were satisfactory, regardless of the interval evaluated. Sampling schemes at different seasons of the year and further spectral and field variables (spectral and biomass) are suggested to improve even more the accuracy of the estimates.

Passive restoration contributes to bird conservation in Brazilian Pampa grasslands

Passive restoration contributes to bird conservation in Brazilian Pampa grasslands

Correction: Gisele Cristina Rubert et al., Evapotranspiration of the Brazilian Pampa Biome: Seasonality and Influential Factors. Water 2018, 10, 1864

The authors wish to make the following corrections to this paper [...]

Tecendo vidas

O objetivo desse artigo foi pesquisar saberes e aspectos identitários relativos ao artesanato em lã no pampa brasileiro. Para alcançar esse objetivo, foram realizadas oito entrevistas com artesãos e artesãs do município Santana do Livramento com auxílio de um roteiro de questões. Os artesãos e as artesãs resgatam a trajetória de suas vidas junto a essa paixão de tecer individualmente ou em grupo, de diferentes formas, preservando a rusticidade. Acompanhando as mudanças do mercado, somando os saberes repassados no interior da família e nos cursos, o artesanato em lã e as pessoas que o fazem garantem a vitalidade da identidade territorial do pampa a cada nova peça que produzem, carregada de significados.
 Palavras-chave: Artesanato. Cadeia da lã. Saberes. Identidade territorial. Pampa brasileiro.

Pampa: Terroir do gado bovino?

Este trabalho visa avaliar as transformações nos sistemas de produção da atividade pecuária bovina de corte de sua origem até o momento, com ênfase na pecuária bovina do Pampa uruguaio e argentino, e da região da Campanha gaúcha, porção do Pampa brasileiro. Centro das modernizações, bem como formador de uma identidade regional e territorial, o Pampa se coloca como uma marca identitária da produção bovina única no mundo. As recentes inovações na atividade pecuária bovina territorializam a vanguarda da modernização técnica. Associada à lavoura, verticaliza o processo produtivo consolidando laços dentro e fora do país com diferentes formas de capital internacional, tanto na produção como nas novas formas de consumo, redefinindo a inserção da atividade pecuária de corte no agronegócio, bem como a dinâmica no mercado interno e externo e a exclusividade do lugar.

Bacterial and Archaeal Communities Change With Intensity of Vegetation Coverage in Arenized Soils From the Pampa Biome.

Arenization occurs in regions that present sandy soils with normal rainfall levels. Predatory use of environmental sources, the dissolution of arenitic rocks and reworking of non-consolidated surface sands intensify this degradation scenario. Thus, this work aimed to evaluate the impact of the arenization process in the Brazilian Pampa Biome and how this phenomenon affects the soil microbial and plant communities. For this purpose, three arenized areas in Southern Brazil (Pampa Biome) were selected and, in each one, three sampling points were studied: arenized (ARA), arenized to grassland transition (AGT), and grassland (GRA) areas. In the three sampling points, soils presented low levels of nutrients, organic matter, mud and pH acidic in all regions but, the presence of vegetation coverage in AGT and GRA areas preserved the topsoil structure. Our study related ARA with bacterial families Alcaligenaceae, Pseudomonadaceae, and Xanthomonadaceae. AGT with bacterial families Bacillaceae and Burkholderiaceae, and plant species Melinis repens (Willd.) Zizka and Paspalum stellatum Humb. and Bonpl. ex Flüggé, and GRA with bacterial families Koribacteraceae, Hyphomicrobiaceae, and Chthoniobacteraceae, and plant species Croton subpannosus Müll.Arg. ex Griseb., Piptochaetium montevidense (Spreng.) Parodi and Elyonurus sp. The three studied areas (as well as sampling points) present soils extremely poor in nutrients with sandy texture, and the bacterial and plant composition well known to be resistant to environmental stresses were dominant. The vulnerability of these areas causes a degradation scenario, which is worsened by agricultural activities. However, in general, this phenomenon is a natural process that occurs mainly due to soil characteristics (poor soils) and climatic variations.

Paracoccidioides spp. in Soil from the Pampa Biome in Southern Brazil.

High rates of paracoccidioidomycosis disease and infection have been recently reported in southern Brazil. However, the knowledgment about the ecoepidemiology of Paracoccidioides spp. in the region is limited, therefore, this study aimed to evaluate the presence of Paracoccidioides spp. DNA in soil samples from a rural area in Southern Rio Grande do Sul, Brazil. Thirty pools of soil samples from Bagé, RS (31º19'53"S 54º06'25"W) were submitted to physicochemical analysis, and to fungal DNA extraction by Norgen Biotek® Kit (Thorold, Canada), followed by Nested PCR technique with ITS4 and ITS5 as external primers, and PBITS-E and PBITS-T as internal primers. DNA amplification products of about 424bp compatible with Paracoccidioides spp. were detected in eight (26.7%) of the 30 pools of samples, being three were sequenced and identified as P. brasiliensis. Positive soils were characterized by high levels of humidity, organic matter, basic saturation, and pH. This study shows for the first time the presence of Paracoccidioides spp. DNA at soils from the Brazilian Pampa Biome, proving that people living in those areas are exposed to the main agent of paracoccidioidomycosis.

Diet, sexual dimorphism and reproduction of sympatric racers Philodryas aestiva and Philodryas patagoniensis from the coastal Brazilian Pampa.

Herein we investigated diet, sexual dimorphism and reproductive biology of two sympatric congeneric species at the coastal Brazilian Pampa, Philodryas aestiva and P. patagoniensis. Analysis of the stomach content of the scansorial Philodryas aestiva revealed that it feeds mainly on Anura and small mammals, while it occasionally consumes Insecta, Squamata and Aves. The more terrestrial Philodryas patagoniensis presented a broader diet, composed mainly of Anura, Squamata and small mammals. Insecta and Actinopterygii were found in lower frequencies. In females of both species, snout-vent length was significantly larger than in males, while tail length/snout-vent length ratio was significantly higher in males. Males reach sexual maturity at smaller sizes than females in both species. Fecundity was higher in P. patagoniensis (3 to 24 eggs; 15 ± 8.15) than in P. aestiva (10 to 20 eggs; X = 14.50 ± 3.53). Females of P. aestiva showed secondary follicles in all seasons while eggs occurred from middle-winter to early-summer. Secondary follicles occurred throughout the year in P. patagoniensis, but concentrated in spring. Eggs occurred in late-summer, middle-autumn and spring. Both species presented positive correlations between SVL and clutch size. Differences in analyzed traits seem to reflect divergences in species morphology and use of habitat/microhabitat.

Comparative trophic ecology of two sympatric canids in the Brazilian Pampa

AbstractStudies on resource utilization by carnivores are essential to assess the role of the species in the ecosystem. These studies help us to understand the mechanisms that influence vertebrate community structure and the relationships between predators and prey. The aims of this study were to compare and describe the food habits of the sympatric Pampas fox (Lycalopex gymnocercus) and crab‐eating fox (Cerdocyon thous) in the Brazilian Pampa, and to evaluate the food niche overlap between them, and infer aspects of habitat preferences on the basis of their prey. For the diet analyses, 25 stomach contents of Pampas foxes and 33 of crab‐eating foxes were collected. We identified 80 prey items (49 for the Pampas fox and 63 for the crab‐eating fox) and grouped them into eight main categories. Mammals and invertebrates were the most frequent items in the diets of both canids, followed by fruits. The trophic niche breadth of the Pampas fox (Bsta = 0.56) was larger than that of the crab‐eating fox (Bsta = 0.47). The diet overlap between them was Ojk = 0.58. However, a PERMANOVA test showed that diets did not differ between species or season. Our results showed that both L. gymnocercus and C. thous had generalist diets, with a great diversity of prey, but based on similar main food items. Items that contributed the most to the diet of the Pampas fox were insects (Gryllotalpidae and Scarabaeidae) and cavies (Cavia aperea) and those that contributed the most to the diet of the crab‐eating fox were fruits of Syagrus romanzoffiana, beetles (Scarabaeidae), amphibians (Leptodactylus spp.) and cavies. This is the first study to describe and compare the food habits of these two species, occurring in sympatry in the Brazilian Pampa.

Evapotranspiration of the Brazilian Pampa Biome: Seasonality and Influential Factors

Experimentally characterizing evapotranspiration (ET) in different biomes around the world is an issue of interest for different areas of science. ET in natural areas of the Brazilian Pampa biome has still not been assessed. In this study, the actual ET (ETact) obtained from eddy covariance measurements over two sites of the Pampa biome was analyzed. The objective was to evaluate the energy partition and seasonal variability of the actual ET of the Pampa biome. Results showed that the latent heat flux was the dominant component in available energy in both the autumn–winter (AW) and spring–summer (SS) periods. Evapotranspiration of the Pampa biome showed strong seasonality, with highest ET rates in the SS period. During the study period, approximately 65% of the net radiation was used for the evapotranspiration process in the Pampa biome. The annual mean ET rate was 2.45 mm d−1. ET did not show to vary significantly between sites, with daily values very similar in both sites. The water availability in the Pampa biome was not a limiting factor for ET, which resulted in a small difference between the reference ET and the actual ET. These results are helpful in achieving a better understanding of the temporal pattern of ET in relation to the landscape of the Pampa biome and its meteorological, soil, and vegetation characteristics.

Wavelet approach applied to EVI/MODIS time series and meteorological data

The aim of this study was to describe the phenology of different types of grasslands from the Pampa and Mata Atlântica biomes in the southern region of Brazil and its relation with meteorological variables, in a time series of EVI/MODIS data using the Wavelet approach (Transform – WT - and Coherence - WC). There is a lack of studies focusing on how climate variability influences the phenology of different Brazilian Pampa grassland typologies. This information is essential to describe the spatio-temporal dynamics of grasslands and contribute to actions of sustainable management and conservation strategies, threatened by crops, forestry, and expansion of overgrazed cattle farms. A series of EVI/MODIS acquired from February 2000 to December 2014, totaling 342 images, were sampled for each of the 10 grassland typologies at the study area. Mean EVI data and the WT indicated when and where changes in the grassland phenological dynamics occurred. The WC, applied to the EVI/MODIS time series with (i) rainfall and (ii) air temperature, helped to identify the correlation between the data. Two well - defined cycles were identified: annual, ranging from 1 to 23 observations, and interannual, from 92 to 184 observations. The different grassland typologies showed similar phenological patterns, although some spatial dependency was observed and related to the different soil and terrain morphometry at the study area. The influence of those abiotic factors on the grassland vegetation, phenological events and their expression on the EVI was also spatially dependent and strongly linked to weather conditions (e.g., the permanence of humidity after rainfall in shallow soils) and climate. The correlation between EVI and air temperature was stronger in the annual cycle for all grassland typologies. For the interannual cycles, El Niño and La Niña events caused higher correlation between EVI data and rainfall.

Ecoregions within the Brazilian Pampa biome reflected in Odonata species assemblies

AbstractBased on vegetation composition, previous studies of the Pampa biome in southern Brazil have defined seven ecoregions within the area. Here, we test this ecoregion approach studying the semi‐aquatic insect group Odonata in five of these regions, aiming at comparing the ecoregions to the more traditional environmental predictors of water quality and land cover. Based on a data set of occupancy comprising 99 species distributed between 131 localities, a one‐way Permutational Multivariate Analysis of Variance was used to compare differences in the species composition between the ecoregions, followed by a Principal Component Analysis to visualize the variation. The composition varied significantly between all groups tested, and the ordination explained 61.8% of the variance. A partial redundancy analysis of ecoregions, land cover and water quality variables explained 71% of the variance in Odonata community structure. Ecoregion was the most important predictor, followed by water quality and land cover. Within these species assemblies, we could select certain species that were representative of a given ecoregion, to which their distribution within the Pampa biome was entirely or mainly confined. Of 24 representative species 41.7% were rare, while the rest were more abundant and, hence, easier to detect. We suspect that the differences found between the Pampa ecoregions might be due to geology, as such factors may be strong determinants of biodiversity. Specific ecological requirements at the family and genus levels also seemed to act selectively on the species compositions within the ecoregions. Today, the Pampa is highly fragmented due to agricultural activities such as rice cultivation, extensive cattle farming and forest plantations. We suggest that an ecoregion‐based approach to the implementation of conservation measures may be the best way to help these distinct species assemblies survive.

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.

On the ecological recognition of Butia palm groves as integral ecosystems: Why do we need to widen the legal protection and the in situ/on-farm conservation approaches?

Brazilian environmental legislation provides protection to native flora in different ways. However, the predominantly non-forest ecosystems of Brazil have no specific legislation protecting their ecological particularities. Many authors have emphasized the relevance of recognizing the ecological importance of non-forest ecosystems and the need to include them in conservation priorities. Southern Brazil, northeastern Argentina and Uruguay harbor one of the most fascinating ecosystems of the southern South American grasslands, the Butia palm groves. These are natural non-forest ecosystems dominated by populations of Butia species (Arecaceae) scattered through the grassy matrix. Land conversion to agriculture, silviculture and urban sprawl are the greatest threats to these palm species. For instance, in the southern Brazilian Pampa grasslands where palm groves were once very abundant, 26% of the natural grasslands have been lost over a period of 30 years. This significant habitat loss is aggravated by the protection of only 0.4 per cent of the Pampa biome within legally designated areas. Furthermore, palm groves are not recognized in Brazilian official vegetation classification systems. Therefore, there is a need to recognize non-forest ecosystems as ecologically integral entities. This implies the necessity of understanding, for instance, that preservation of palm groves is critical to re-establish the natural processes of these ecosystems, i.e., to begin to support the natural renewal process of palm groves, jointly with conserving the natural grassy matrix and all its diverse flora and fauna. Public policies focusing on these ecosystems and species must include promotion of sustainable use of their products, using their economic value to increase interest in their conservation. Practices that ensure the renewal of populations, such as conservative grazing management and ecosystem restoration, also need to be implemented.

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.

Plant species richness record in Brazilian Pampa grasslands and implications

Species richness remains one of the most valuable type of information for biodiversity conservation. Here, we report a plant richness record in the Brazilian Pampa. We found 56 vascular plant species in a single plot of 1 × 1 m in a privately owned grazed grassland in a region with shallow soils. This number is considerably higher than common species numbers in similar surveys and highlights the high plant diversity in South Brazilian grasslands. We take our record as an opportunity to reflect on some issues of high importance if we wish to reach conservation goals: much of the biodiversity is inside private lands, and these should be more in the focus of conservation efforts; field research, especially quantitative sampling, continues to be essential to improve knowledge on biodiversity and its distribution patterns; training biologists to be able to carry out biodiversity assessments and to interpret the results should be a key issue for universities. We hope that the communication of this record will encourage new scientific discoveries and raise social interest about the conservation of grasslands in South Brazil.

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

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

Trophic ecology of sympatric small cats in the Brazilian Pampa.

Information about resource partitioning among small cat species that live in sympatry in South America is fairly incomplete. Knowledge about feeding habits is essential for understanding the role of these predators in the environment, the impact on prey populations, and potential competition among themselves and with other carnivores. This study aimed to describe and compare the diet of four sympatric small cats in the grasslands of southern Brazil. We analysed the stomach contents of 37 Geoffroy’s cats (Leopardus geoffroyi), 27 margays (Leopardus wiedii), 14 pampas cats (Leopardus colocola), and 20 jaguarundis (Herpailurus yagouaroundi) obtained as road kill in the Brazilian Pampa in southern Brazil. Small mammals were the most representative class consumed by all cats, followed by Aves, Reptilia, and Amphibia. Some items, such as rodents Cavia aperea, Akodon sp., Oligoryzomys sp. and Passeriformes were consumed by all cat species. Niche overlap varied widely, from 10% (margay x jaguarundi) to 92% (jaguarundi x pampas cat). Niche breadth indicated that jaguarundi were the most specialized of the cats (Bsta = 0.24) in this region, with a diet closely associated to C. aperea. Margay consumed more items associated with arboreal behaviour than other cat species, but consumed more terrestrial items than arboreal ones. The pampas cat consumed mostly terrestrial species associated with open fields. Geoffroy’s cat consumed mammals found in a diversity of habitats, indicating high ecological flexibility. Species with more similarity in diet such as jaguarundi and pampas cat probably present temporal segregation in activity. In conclusion, despite their habitat and diet similarities, these four species explore distinct microhabitats by foraging different prey groups, what favor them to live in sympatry.

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.

Negative effects of an invasive grass, but not of native grasses, on plant species richness along a cover gradient

AbstractImpacts of invasive plants on plant communities are not universal, and effects may differ depending on the life form of the invading species. At three sites in the Brazilian Pampa region, we assessed the effects of invasion by Eragrostis plana Nees, considered to be the most problematic invasive plant in South Brazilian grasslands, on local plant communities. Specifically, we evaluated effects on species richness, community evenness and richness of principal functional groups along an invasion gradient. Based on plant community data, we also evaluated the effects of dominant native species on the same plant community features, thus being able to assess the relative impacts of an invasive species compared to abundant native species. Eragrostis plana invasion reduced total plant richness, with some distinct effects regarding plant functional groups, and differently from other coexisting native species that did not show the same effects even when of high abundance. Grasses were the most affected plant group when E. plana cover increased, consistent with the limiting similarity hypothesis. Overall, our results indicate clear negative effects of this invasive plant on the grassland communities. Comparing the effects of an invasive species to those of coexisting natives is crucial for disentangling the real impact of an invader. Our results demonstrate that effects are consequence of species identity, and not only of high abundances.