Brazilian Savanna Research Articles

Strict protected areas are essential for the conservation of larger and threatened mammals in a priority region of the Brazilian Cerrado

Assessing protected area (PA) effectiveness is key to ensure the objectives of habitat protection are being achieved. There is strong evidence that legal protection reduces loss of natural vegetation, but biodiversity loss can still happen without significant changes in vegetation cover. Here we use data from a specifically designed camera trap survey to conduct a counterfactual assessment of PA effectiveness at safeguarding local biodiversity in the Brazilian Cerrado. We surveyed the mammal community in 517 locations at the Sertão Veredas-Peruaçu mosaic, distributed across five strict PAs (264 survey sites in five arrays) and two multiple-use PAs with low management levels (253 survey sites in four arrays). We adopted a multi-species occupancy framework to analyse our dataset while also controlling for confounding factors not directly related to protection. Of the 21 species assessed, nine had higher occupancy in strict PAs, one had higher occupancy in multiple-use PAs, and ten did not respond to protection level. Site species richness was nearly twice as large in areas under stricter protection, with even greater differences for species richness of globally threatened and larger mammals (>15 kg). Overall we demonstrated that the strict PAs surveyed support higher mammal diversity than similar areas under less restrictive management, with a particular strong effect on larger and threatened species. Given that strict PAs cover only 3% of the Cerrado, our results suggest that expanding the area under strict protection is likely to benefit iconic species of the Brazilian savanna, such as the maned wolf and giant anteater.

The need to consider searcher efficiency and carcass persistence in railway wildlife fatality studies

To improve mitigation planning on railways, it is crucial to accurately assess the number of fatalities resulting from this type of infrastructure. To illustrate the relevance of considering the two main errors from the sampling process (searcher efficiency and carcass persistence), we corrected the estimation of mammal fatalities (> 1 kg) on a 750-km railway located in the Brazilian Savanna accounting for these errors. Observed fatalities were collected by two observers in a rail inspection vehicle (RV). We estimated searcher efficiency comparing the number of carcasses found during the searcher efficiency trials on foot and by RV on the same subsections of the railway. Carcass persistence was estimated based on trials with a subset of carcasses that had their persistence verified over three consecutive days. Searcher efficiency was 29.8% and daily carcass persistence probability was 99.7%. Nine surveys on the entire railway (2015–2016) recorded 1950 carcasses and, after correcting for the sampling errors, we estimated that 4286 mammals died on this railway in 23 months. This estimate is 2.2 times larger than the observed number of fatalities. These errors should not be neglected, as our results demonstrate that the number of observed carcasses is a misperception in relation to the true number of fatalities caused by the railway. However, our results also indicate that dealing with these errors in railway ecology is still a challenge. We stress the need to test more suitable sampling designs for fatality estimates on railways.

Microsatellites for the Neotropical Ant, Odontomachus chelifer (Hymenoptera: Formicidae)

Odontomachus chelifer (Latreille) (Ponerinae) is a ground-dwelling, predominantly carnivorous ant whose colonies may contain multiple egg-laying queens and are potentially susceptible to border effects in the Brazilian savanna known as Cerrado. The ecology and natural history of O. chelifer is well studied, but very little is known about the genetic diversity of O. chelifer colonies. In this study, we developed microsatellite markers for the study of genetic variation in O. chelifer. We created a microsatellite-enriched library that resulted in the development and characterization of 22 markers, of which 18 were found to be polymorphic in the population studied. The mean expected heterozygosity was 0.59, whereas the mean rarified allelic richness was determined as 4.27 alleles per locus. The polymorphism level detected was similar to genetic diversity estimates found in other poneromorph ant species. The microsatellites developed here are likely to be useful for the investigation of colony structure, functional polygyny, breeding system, and population genetics in O. chelifer. Moreover, the description of O. chelifer’s genetic diversity is crucial for its conservation and maintenance of its ecological role in the Cerrado savanna.

Natural superficial water storage and aquifer recharge assessment in Brazilian savanna wetland using unmanned aerial vehicle and geophysical survey

Human pressure on the water resources provided by natural isolated wetlands has intensified in Brazil due to an increase in agricultural land equipped with irrigation. However, the amount of water stored in these areas and its contribution to aquifer recharge is unknown. This study aimed to quantify the amount of water that can be retained in a natural wetland and to propose a model of groundwater recharge. We used remote sensing techniques involving unmanned aerial vehicle to map the wetland and highlight its internal morphology, using a red–green–blue orthomosaic and a digital surface model. The 2-D inversion and a pseudo-3-D model from electrical resistivity tomography data were used to visualize the subsurface structures and hydrologic flow paths. The wetland is a reservoir storing up to 416.996 m3 of water during the rainy months. Distinct internal compartments characterize the wetland topography and different water-volume storage, lower in the border and higher in the center. A leakage point connects surface water to groundwater through direct vertical flow, which constitutes the aquifer recharge zone. Remotely sensed very high-resolution images allied with geophysical techniques allowed complete surface and subsurface imaging and offered visual tools that contributed to understanding the hydrodynamics of the wetland.

Variações espaço-temporais na abertura do dossel em diferentes tipologias vegetais sob efeito de fogo

Os domínios fitogeográficos Atlântico e dos Cerrados brasileiros destacam-se pelo alto grau de ameaça de seus remanescentes, fazendo com que o estudo de sua ecologia seja de suma importância para a conservação desses domínios. Apesar da existência de distúrbios ecológicos naturais, a ação humana pode agravar a ocorrência desses fenômenos, como por exemplo: o aumento da frequência do fogo em ambientes naturais. Mesmo o dossel, camada superior da vegetação, é prejudicado direta ou indiretamente pela ação desse distúrbio. Além disso, as características do dossel são determinantes para a dinâmica de regeneração das comunidades vegetais, pois suas condições regulam os níveis de luminosidade que chegam às camadas inferiores da vegetação. Assim, este trabalho buscou estudar as variações na abertura do dossel de um mosaico vegetacional inserido em uma área de contato entre os domínios Atlântico e dos Cerrados, com o intuito de identificar como se dão essas alterações entre as tipologias vegetais analisadas e qual a influência da ocorrência de fogo nas oscilações no estrato superior da vegetação. Para isso, o estudo acompanhou as mudanças na abertura do dossel, com o uso de fotografias hemisféricas, em diferentes unidades vegetacionais por três anos, a partir da ocorrência de um evento de fogo no local. Os resultados obtidos mostraram que fitofisionomias semelhantes apresentaram níveis de abertura do dossel parecidos, da mesma forma que exibiram um padrão de oscilação similar entre si. Por fim, depreende-se que o fogo se mostrou como um modificador indireto do dossel, uma vez que as próprias características da vegetação têm a capacidade de controlar os impactos desse tipo de distúrbio.

A IMPORTÂNCIA DE AULAS TEÓRICA E DE CAMPO PARA ABORDAR QUESTÕES AMBIENTAIS DO BIOMA CERRADO: UM ESTUDO DE CASO

Devido aos problemas ambientais enfrentados pelo bioma Cerrado é urgente aplicar ações voltadas à sua proteção. Nesse sentido, a educação ambiental se mostra como uma excelente abordagem para a conscientização dos efeitos das ações humanas nesse bioma. Neste trabalho, realizado em março de 2018 no Instituto Federal de Brasília (Campus Recanto das Emas), foi avaliada a eficácia de aulas teórica e de campo para abordar os problemas ambientais observados nesse bioma. Nossos resultados sugerem que ambas as aulas foram satisfatórias. Isso porque em ambos os casos houve rendimento similar e aumento do interesse dos discentes pela questão ambiental. Portanto, os dados deste estudo sugerem que reflexões e ações discentes sobre questões ambientais independem da estratégia didática adotada.

Topography, more than land cover, explains genetic diversity in a Neotropical savanna tree frog

AbstractAimEffective conservation policies rely on information about population genetic structure and the connectivity of remnants of suitable habitats. The interaction between natural and anthropogenic discontinuities across landscapes can uncover the relative contributions of different barriers to gene flow, with direct consequences for decision‐making in conservation. We aimed to quantify the relative roles of land cover and topographic variables on the population genetic differentiation and diversity of a stream‐breeding savanna tree frog (Bokermannohyla ibitiguara) across its range.LocationSerra da Canastra mountain range, Cerrado of Minas Gerais State, Brazil.MethodsWe collected samples and extracted DNA samples from 12 populations within and outside a strictly protected park, and used 17 microsatellite markers to assess genetic structure, among‐population differentiation and within‐population diversity measures. We incorporated landscape data derived from digital models and satellite images to create connectivity matrices to correlate with genetic differentiation using Mantel tests. We used generalized linear models and path analyses to assess the roles of each landscape variable in shaping genetic diversity in this species.ResultsPopulations within and outside the park boundaries belonged to four genetic clusters. Most populations showed evidence of limited gene flow, with significant genetic differentiation, except for those within the park, which also had higher levels of allelic richness and heterozygosity. However, genetic differentiation among populations in this landscape was primarily explained by topographic complexity. Likewise, within‐population measures of genetic diversity were best explained by models including elevation and topographic complexity, and not the amount of natural habitat or gallery forests.Main conclusionsOur results underscore that topography may be a strong historical factor shaping genetic structure among amphibian populations. Therefore, effective conservation strategies for endangered amphibians should avoid focusing exclusively on habitat suitability, and incorporate topographic complexity, which seems to be a key factor for the fauna of the extremely threatened Brazilian savanna.

DYNAMICS OF AGRICULTURAL EXPANSION IN AREAS OF THE BRAZILIAN SAVANNA BETWEEN 2000 AND 2019

Abstract. The information survey and the land use and land cover (LULC) change monitoring are essential to understand the changes in the landscape and their impacts on the environment. The Brazilian savanna (Cerrado) constitutes the second largest biome in Brazil and is highly relevant because of its rich biodiversity. The Cerrado in the Maranhão State is facing a high conversion rate of its natural vegetation into agricultural systems because of the agricultural development policies. This article aims to analyze and quantify the LULCC in the Chapadinha microregion, Maranhão State, Brazil, by comparing Landsat satellite images from 2000, 2009, and 2019. The Chapadinha microregion covers an area of more than 14,000 km2 and, since 2000, presents significant spatial transformations related to agricultural expansion. The goal of this expansion is the economic development based on agricultural commodities (mainly soybean monoculture) for exportation. The study area is the third microregion in terms of agricultural production in Maranhão. The satellite image interpretation showed a reduction of more than 800 km2 of natural vegetation.

Woody Aboveground Biomass Mapping of the Brazilian Savanna with a Multi-Sensor and Machine Learning Approach

The tropical savanna in Brazil known as the Cerrado covers circa 23% of the Brazilian territory, but only 3% of this area is protected. High rates of deforestation and degradation in the woodland and forest areas have made the Cerrado the second-largest source of carbon emissions in Brazil. However, data on these emissions are highly uncertain because of the spatial and temporal variability of the aboveground biomass (AGB) in this biome. Remote-sensing data combined with local vegetation inventories provide the means to quantify the AGB at large scales. Here, we quantify the spatial distribution of woody AGB in the Rio Vermelho watershed, located in the centre of the Cerrado, at a high spatial resolution of 30 metres, with a random forest (RF) machine-learning approach. We produced the first high-resolution map of the AGB for a region in the Brazilian Cerrado using a combination of vegetation inventory plots, airborne light detection and ranging (LiDAR) data, and multispectral and radar satellite images (Landsat 8 and ALOS-2/PALSAR-2). A combination of random forest (RF) models and jackknife analyses enabled us to select the best remote-sensing variables to quantify the AGB on a large scale. Overall, the relationship between the ground data from vegetation inventories and remote-sensing variables was strong (R2 = 0.89), with a root-mean-square error (RMSE) of 7.58 Mg ha−1 and a bias of 0.43 Mg ha−1.

Termite functional diversity along an elevational gradient in the Cerrado of Mato Grosso do Sul

Termites are dominant invertebrates in tropical environments and are important intermediate species of decomposition in terrestrial ecosystems. The study aimed to characterize how termite richness and feeding group diversity vary along an elevational gradient in the Brazilian savanna. Termites were sampled within a standardized 100 × 2 m transect at undisturbed Cerrado sites along an elevational gradient from 210 to 600 m asl. Termite diversity declined with the increase in elevation in the Serra de Maracaju, with an elevation range of 400 m and strong undulated relief. Higher elevations cause a significant decrease in the number of grass-litter-feeding species and Syntermitinae species, associated with more acidic soils with lower saturation by exchangeable bases. Beta and, especially, alpha diversity at plot level were responsible for the observed diversity of almost all groups, except for wood-feeders. Our results suggest a greater change in termite taxonomic and functional diversities at a lower elevational gradient than at high elevations. Finally, this study gives some insights that even in a rockier physiognomy, probably with fewer resources to be explored the termite diversities was still higher than in a pasture area at lower elevations.

A multibiomarker approach in the caged neotropical fish to assess the environment health in a river of central Brazilian Cerrado

Water safety is a world-wide concern and several efforts have been made in order to ensure the conservation of aquatic ecosystems. Water quality monitoring must be performed with an integrated approach using biomonitor organisms allied to water parameters. Nonetheless, very few studies have focused on biomarker responses in neotropical fish, especially in the freshwater ecosystem of Brazilian Cerrado savanna. In present study, the active biomonitoring of the João Leite river (central Brazilian Cerrado river) was performed through the evaluation of biomarker responses in caged Astyanax lacustris in combination with land use classification and analysis of water parameters. Caged fish were exposed for seven days at four sites along the river and two control groups were kept in a tank under controlled conditions. Results showed that pasture was the predominant land use in the João Leite river basin (54.07%), followed by natural vegetation (34.92%) and other kind of land use (11.01%). Water analyses showed metal concentrations (Mn and Fe) above the maximum allowed by Brazilian regulation, with particularly higher concentrations at Site 2 (near to pasture area). Biomarker responses did not show significant differences for somatic and mutagenic biomarkers between sites. However, the comet assay showed high DNA damage at Sites 2 and 3, indicating genotoxic effects in caged fish at pasture areas. Histopathological analysis showed highest frequency of leukocyte infiltration in liver of fish from Site 2, confirming the ecotoxic effects on A. lacustris in streams impacted by grazing activities. DNA damage and leukocyte infiltration in fish hepatic tissues were sensitive biomarkers in the neotropical fish A. lacustris to assess the environment health of the Cerrado river. These results showed the importance of using a multibiomarker approach in environmental risk assessment, especially in areas more at risk from anthropogenic pollution.

Contrasting effects of herbivore damage type on extrafloral nectar production and ant attendance

The ant-plant mutualism mediated by extrafloral nectaries (EFNs) is based on the provision of extrafloral nectar (a sugar-rich liquid) in exchange for ant defense against herbivores. The extrafloral nectar production can vary depending on the intensity or types of leaf damage caused by different mouthparts of insect herbivores (i.e., sucking or chewing insects). However, it is poorly known how the type of herbivore damage changes the outcomes of tri-trophic interactions. Here, we address how the damage inflicted by different herbivore groups affects extrafloral nectar production and ants’ attendance and aggressiveness. Through an experimental field study, we tested whether the type of leaf damage, sucking or chewing, changes extrafloral nectar volume and sugar concentration, and subsequently ant composition and behavior. We evaluated the extrafloral nectar production and ant attendance and aggressiveness before and after simulated herbivory in Qualea parviflora (Vochysiaceae), a Brazilian savanna EFN-bearing plant. We found that only plants with sucking damage increased the sugar concentration of their extrafloral nectar, only plants with chewing damage increased ant abundance, and surrogate herbivore predation differed before and after simulated herbivory only for sucking damage. We provided the first evidence that the type of damage can influence ant aggressiveness via changes in extrafloral nectar production, translating to changes in the outcomes of this ant-plant mutualism. Ultimately, studies should consider the effects of herbivore damage type when studying insect-plant interactions.

Water infiltration in the Brazilian tropical savanna: the case of Cerrado típico

The Brazilian savanna, regionally known as Cerrado is an important water source due to its spatial position in the highlands known as Planalto Central of Brazil. Yet, the hydrological functioning of such complex ecosystems and its many variations is poorly understood. In this paper, we characterized the soil surface permeability to water under in one of the most common vegetation types: the Cerrado típico which is a type of savanna. In doing so, we measured infiltration capacity using the Mini-Disk infiltrometer (n = 15) and soil resistance to penetration using the Stolf penetrometer (n = 7) in a Latossolo (oxisol) under Cerrado típico located in Brasília (Planaltina), Distrito Federal, Brazil. Our results indicated a high infiltration capacity under Cerrado típico which is potentially associated with a low penetration resistance. This fact might highlight the importance of the natural undisturbed ecosystems, in this case Cerrado típico, as a land-cover which favors hydrological processes which, in turn, promotes soil-groundwater recharge that are inportant to maintain water bodies and reservoirs in the region.

Paradigmas da Gestão do Fogo em Áreas Protegidas no Mundo e o Caso da Estação Ecológica Serra Geral do Tocantins

Duas abordagens claras de gestão do fogo podem ser observadas em áreas protegidas pelo mundo: uma está associada ao paradigma do fogo zero, pautada em políticas de proibição do uso do fogo e de exclusão do fogo dos ecossistemas; e outra baseada no manejo do fogo­, que considera o papel ecológico do fogo nos ecossistemas, suas necessidades de uso para práticas tradicionais e o contexto territorial no qual estão inseridas. Este artigo emerge de uma longa reflexão e aprendizados dos autores a partir da experiência de mudança de paradigmas na gestão do fogo na Estação Ecológica Serra Geral do Tocantins, sistematizada em uma dissertação de mestrado profissional. O presente ensaio apresenta e caracteriza os dois paradigmas e derivações, à luz de uma perpectiva holística que considerou a influência dos contextos ecológico, sócio-político e normativo na determinação de política de gestão de uso ou exclusão do fogo em unidades de conservação, especialmente aquelas que protegem ecossistemas naturalmente propensos a sua passagem.

Effect of Season and Nitrogen Fertilization on the Agronomic Traits and Efficiency of Piatã Grass in Brazilian Savanna

The aim of the present study was to evaluate the agronomic traits in the pre- and post-grazing and the nitrogen use efficiency of Piatã grass that was subjected to nitrogen fertilization throughout the seasons of the year. The experiment was performed in a randomized block design with four treatments (0, 150, 300, and 450 kg ha−1 N). Grazing was performed with sheep when the forage canopy reached 95% light interception up to 20 cm height of post-grazing. The pre-grazing forage mass of the Piatã grass showed a behavior (p < 0.05) linear to nitrogen fertilization, with higher and lower values in spring and winter, respectively. The post-grazing forage mass responded linearly (p < 0.05) to nitrogen fertilization, with an increase of 43.12% for the dose of 450 kg ha−1 N in relation to pastures without nitrogen fertilization. When the non-fertilized pasture was compared with the highest nitrogen dose, a reduction of 21.79% dead tissue was observed in the post-grazing forage mass. The highest nitrogen use efficiency was obtained with the dose of 450 kg ha−1 N. The forage mass production of the Piatã grass in the pre- and post-grazing conditions are positively influenced by nitrogen fertilization and the seasons of the year, with lower values in winter.

SEMANTIC SEGMENTATION OF BRAZILIAN SAVANNA VEGETATION USING HIGH SPATIAL RESOLUTION SATELLITE DATA AND U-NET

Abstract. Large-scale mapping of the Brazilian Savanna (Cerrado) vegetation using remote sensing images is still a challenge due to the high spatial variability and spectral similarity of the different characteristic vegetation types (physiognomies). In this paper, we report on semantic segmentation of the three major groups of physiognomies in the Cerrado biome (Grasslands, Savannas and Forests) using a fully convolutional neural network approach. The study area, which covers a Brazilian conservation unit, was divided into three regions to enable testing the approach in regions that were not used in the training phase. A WorldView-2 image was used in cross validation experiments, in which the average overall accuracy achieved with the pixel-wise classifications was 87.0%. The F-1 score values obtained with the approach for the classes Grassland, Savanna and Forest were of 0.81, 0.90 and 0.88, respectively. Visual assessment of the semantic segmentation outcomes was also performed and confirmed the quality of the results. It was observed that the confusion among classes occurs mainly in transition areas, where there are adjacent physiognomies if a scale of increasing density is considered, which agrees with previous studies on natural vegetation mapping for the Cerrado biome.

Baru Pulp (Dipteryx alata Vogel): Fruit from the Brazilian Savanna Protects against Oxidative Stress and Increases the Life Expectancy of Caenorhabditis elegans via SOD-3 and DAF-16.

Fruits are sources of bioactive compounds that are responsible for several biological activities. Therefore, this study aimed to identify the chemical composition of the pulp of the Brazilian Savanna fruit Dipteryx alata; evaluate its toxic effects, influence on the life expectancy of the nematode Caenorhabditis elegans, and its antioxidant activities in vitro and in vivo; and describe the mechanisms involved. The chemical compounds identified include phenols, terpenes, fatty acid derivatives, vitamins, and a carboxylic acid. The in vitro antioxidant activity was demonstrated by radical scavenging methods. in vivo, the D. alata fruit pulp was not toxic and promoted resistance to oxidative stress in nematodes exposed to a chemical oxidizing agent. Furthermore, it promoted an increased life expectancy in wild-type nematodes and increased the expression of superoxide dismutase and the nuclear translocation of DAF-16. These results suggest that the beneficial effects identified are related to these two genes, which are involved in the regulation of metabolic activities, the control of oxidative stress, and the lifespan of C. elegans. These beneficial effects, which may be related to its chemical constituents, demonstrate its potential use as a functional and/or nutraceutical food.

Genetic structure of two Acrocomia ecotypes (Arecaceae) across Brazilian savannas and seasonally dry forests

The species of Acrocomia are popularly known as Macaw palm due to their importance as a food source for Anodorhynchus (Psittacidae). They are monoecious, with a mixed reproductive system, and high ecological and economic importance. There is controversy regarding the taxonomic status of Acrocomia aculeata and Acrocomia totai as different species; to avoid misunderstanding, we adopted the ecotype terminology. Using range-wide sampling in Brazil and based on microsatellite data, we aimed to understand the genetic diversity of A. aculeata and A. totai and to evaluate if the genetic structure between them was different. Our results support a separation of Acrocomia aculeata and A. totai based on the patterns of genetic variation between the ecotypes. These findings are supported by the optimal clustering of K = 7, congruent with network analysis, as well as pairwise genetic differentiation and detected barriers to gene flow. We found no evidence of recent bottlenecks in all populations, excepting two. The genetic structure was mainly associated with rivers and topography, but there was also evidence of gene flow among most populations. The association of the genetic structure with the geographical distribution of populations was more evident in A. aculeata than in A. totai. Populations located at the western portion of Brazil showed a high degree of admixture, notably among A. totai populations. The identification of areas with the highest genetic diversity of Acrocomia contributes useful information for plant breeding programs and the detection of potential genotypes of interest for germplasm collections.

Soil compaction affects the silage quality of sunflower and Paiaguas palisadegrass (Brachiaria brizantha) grown on a Latosol in the Brazilian savanna

On the basis of the natural seasonality of pastures during the dry season, preservation of forage, especially silage, is necessary. However, the effects of soil compaction within sunflower and grass crop fields on the nutritional quality of the silage produced are unknown. Therefore, the aim of this study was to evaluate the fermentation and nutritional quality characteristics of sunflower silage under both monocropping and intercropping systems [with Paiaguas palisadegrass (Brachiaria brizantha)] under various degrees of soil compaction. A split-plot randomized complete block design was adopted. In the main plots, the treatments were bulk density values affected by the following traffic intensities: 0, 2, 10 or 30 passes of a tractor with tire wheels weighing 4.9 Mg. The subplots involved forage systems composed of sunflower as a monocrop or intercropped with Paiaguas palisadegrass. The fermentation, nutritional characteristics and in vitro digestibility of the silage were evaluated. Under the various aforementioned conditions, the agronomic characteristics of the forage were affected by increased soil compaction, resulting in changes in the fermentation and nutritional characteristics of the silage. The results showed that intercropping with Paiaguas palisadegrass and adequate proportions of sunflower allow good fermentation. This study recommends the adoption of practices that mitigate soil compaction and intercropping because of the increased forage productivity and the possibility of indirect renewal of the pasture.

Soil compaction affects sunflower and Paiaguas palisadegrass forage productivity in the Brazilian savanna

Integrated crop-livestock systems maximize land use, infrastructure and labor; diversify production; and minimize costs, thereby reducing risks and adding value to agricultural products. However, growing mechanically harvested crops can negatively affect soil structure, reducing plant biomass productivity. The present study aimed to evaluate soil compaction and its effects on the forage productivity of sunflower and Brachiaria brizantha cv. BRS Paiaguas during the second cropping period. The experiment was conducted as a split-plot randomized complete block design with four replications. Four compaction levels represented by traffic from an agricultural tractor were established: 0 (absence of compaction), 2, 10 and 30 passes over the same spot. Two forage systems were established in the subplots: sunflower grown solely as a monocrop (40,000 plants ha-1) or intercropped with Paiaguas palisadegrass (10 plants linear m-1). The following parameters were quantified: soil bulk density, plant height, capitulum diameter and 1000-achene weight for sunflower; stem length and the leaf/stem ratio for Paiaguas palisadegrass; and total and partitioned forage productivity. The results showed that sunflower was highly sensitive to soil compaction and that the development and productivity of this species decreased in response to the greatest bulk density, which in turn affected the Paiaguas palisadegrass. Overall, intercropping is recommended for increased forage productivity.