Identification and Analysis of Burned Areas in Ecological Stations of Brazilian Cerrado

Several studies pointed out soil properties as the prime determinant of cerrado (the Brazilian savanna) physiognomies, and a gradient from “campo cerrado” (a shrub savanna) to “cerradao” (a tall woodland) has been correlated with a soil fertility gradient. Based on this hypothesis, we investigated soil-vegetation relationships in the Pe-de-Gigante Reserve (Sao Paulo State, Southeastern Brazil). We randomly distributed 10 quadrats (10 × 10 m) on each of the following physiognomies: “campo cerrado”, “cerrado sensu stricto”, “cerradao”, and seasonal semideciduous forest, previously defined by the analysis of satellite images (LANDSAT-5). We sampled the woody individuals with stem diamete r>3c m atsoil level, identifying their species. In each quadrat, we collected soil samples at the depths of 0–5, 5–25, 40–60, and 80–100 cm, and determined pH, K, Ca, Mg, P, Al, H + Al, base saturation, aluminium saturation, cation exchange capacity, and percentage of sand, clay and loam. Obtained data were submitted to a canonical correspondence analysis (CCA) and to a detrended correspondence analysis (DCA). Our results showed a clear distinction between semideciduous forest and the cerrado physiognomies, based in soil parameters. The former was related to higher concentrations of cations and clay in the soil, while the latter was related to higher concentrations of exchangeable aluminium in the soil surface. The three cerrado physiognomies – “campo cerrado”, “cerrado sensu stricto”, and “cerradao” – could not be distinguished considering plant density and the analysed soil features.

Savannas are the most sensitive ecosystems to future changes in land use and climate. Therefore, understanding of the factors underpinning savanna ecosystem function is urgently required for ecologically-relevant conservation and management. This thesis aims to address this knowledge gap, investigating how local conditions and landscape features influence soil microbial attributes, and the resistance and resilience of soil functioning within the three distinct vegetation types of the Brazillian Cerrado biome: Gallery forest, Veredas and Cerrado sensu stricto. Firstly, I evaluated how local vegetation characteristics and soil physico-chemical properties interact and influence soil microbial attributes (Chapter 2). Secondly, I investigated how landscape-scale anthropogenic disturbance and topography affect soil microbial community structure and enzyme activity (Chapter 3). I also assessed how soil CO2 emissions are related to microbial attributes and topography, and the resistance and resilience of soil functioning (respiration) of the vegetation types in response to drought and drying-rewetting (Chapter 4). Lastly, I conducted an experiment to investigate the mechanisms underpinning C mineralisation in rewetted soils from the different Cerrado vegetation types (Chapter 5). At the local scale, I found different patterns in above- and below-ground interactions within the three vegetation types. Soil physico-chemical properties strongly affected soil microbial attributes in Gallery forests and Veredas, whereas vegetation characteristics were the main determinant in Cerrado sensu stricto. At the landscape scale, I found topography to be the major predictor of microbial attributes in all vegetation types, and that anthropogenic disturbance influences soil microbial communities both positively and negatively. Veredas soils were the most resistant to drought, while Gallery forests soils were the most resilient in their reponse to rewetting after drought. I also discovered that soil organic matter quality combined with nutrient availability influenced different mechanisms underpinning soil C stock and release to the atmosphere across the different Cerrado types. Based on these findings, I discuss the importance of flooding regimes in the wetland vegetation types (Gallery forest and Veredas) for ecosystem functioning, and implications for future land-use and climate change in the Cerrado biome (Chapter 5). I emphasize the need for Brazilian environmental legislation to prioritize the integral conservation of periodically flooded areas.

Seasonal landscape and spectral vegetation index dynamics in the Brazilian Cerrado: An analysis within the Large-Scale Biosphere–Atmosphere Experiment in Amazônia (LBA)

Arbuscular mycorrhizal community in soil from different Brazilian Cerrado physiognomies

The orchid bees are a very important group of pollinators distributed in the Neotropics. Although a lot of studies concerning male euglossine bees have been done in this region, few works have so far been carried out in the Cerrado biome. This manuscript has the main objective to present the orchid bee community from a Gallery Forest in the Northeastern Brazilian Cerrado landscape, taking account the species composition, abundance, seasonality and hourly distribution. Male euglossine bees were collected monthly from October 2007 to May 2009, in the Reserva Florestal da Itamacaoca belonging to the Companhia de Agua e Esgoto do Maranhão, in Chapadinha municipality, Maranhão State. The scents eucalyptol, eugenol and vanillin were utilized, between 07:00 and 17:00hr, to attract the euglossine males. Cotton balls were dampened with the scents and suspended by a string on tree branches 1.5m above soil level, set 8m from one another. The specimens were captured with entomological nets, killed with ethyl acetate and transported to the laboratory to be identified. A total of 158 individuals and 14 species of bees were recorded. The genus Eulaema was the most representative group of euglossine bees in relation to the total number of the sampled individuals, accounting for 50.6% of bees followed by Euglossa (26.6%), Eufriesea (15.2%) and Exaerete (7.6%). The most frequent species were Eulaema nigrita (27.8%), Eulaema cingulara (19%) and Euglossa cordata (18.3%). Many species typical of forested environments were found in samples, like Euglossa avicula, Euglossa violaceifrons and Eulaema meriana, emphasizing the role played by the Gallery Forests as bridge sites to connect the two great biomes of Amazonia and Atlantic Forest. The occurrence of Exaerete guaykuru represents the second record of this species for the Neotropical region, and both records coming from the Gallery Forest zones. The male euglossine bees were sampled mainly in the dry season, where 62.5% of the individuals were collected in that period. Eufriesea species appeared at the baits only in the wet season. The hourly frequency of bees at scent baits showed a clear preference for the morning period, where 87.9% visited the baits from 07:00 to 12:00hr. The euglossine bee fauna found in the Northeastern Maranhão Cerrado is represented chiefly by species of large geographic distribution and by some forest bee species, where their occurrence is maybe related to to the environmental conditions supported by the Gallery Forest ecosystem.

Little is known about the termite fauna of the different vegetation physiognomies in the Cerrado biome. It is suggested that the species compositions in grassland and savanna areas are closely related to each other, and quite distinct from those of forests. This study compared the species composition from five different physiognomies of Cerrado, and tested the hypothesis that the termite faunas of savannas and grasslands form a distinct group from that of forests. The study was conducted in the Parque Estadual da Serra de Jaraguá, state of Goiás, Brazil. Termites were sampled from two physiognomies of savanna, one natural grassland, one pasture, and one gallery forest. A transect with 10 parcels of 5x2 m was established in each physiognomy. The relative abundance was inferred by the number of encounters, termites were classified in feeding guilds, and the dissimilarity in the species composition between the physiognomies was calculated. A total of 219 encounters, of 42 species of two families were recorded. The most abundant feeding guilds were the humivores (98) and xylophages (55). The physiognomies with the largest number of species were rupestrian cerrado (23 species) and cerrado sensu stricto (21). The physiognomies had a similar species composition (less than 55% dissimilarity), mainly the natural open areas. The hypothesis of a distinct fauna of termites in forest vegetation was refuted. The termite fauna of gallery forest is very different from that of pasture, but most species also occur in natural open areas. The impact of pasture on the diversity and composition of termites seems to be significant, but the impact is even greater on the proportion of the feeding guilds, reducing the proportion of xylophages and intermediates.

The relationship between a species and its environment may result in different distribution patterns, depending on spatial scale. In this regard, habitat and climatic variables can directly affect species distribution and occurrence. An increasing number of studies seek to understand species occupancy as a function of habitat and climatic factors, identifying key variables to which species respond. In the Cerrado region studies with bird species in this area are lacking. The Cerrado is one of the largest tropical savannas in the world and the second-largest vegetation formation in South America. About 72% of bird species are dependent or partially dependent on forest formations and 43% of the 30 endemic species are forest birds. Assessing the relationship between species and their abiotic environment is important to understand how spacial scale, habitat and climatic variables affect organisms distribution and abundance. Thus, considering the lack of information on the Cerrado biome, studies occupancy patterns are needed. Our aim was to understand distribution patterns of Cerrado endemic forest bird species and which factors affect their occurrence in macro and local scale. Also, we assessed and compared estimation methods of species geographic distribution that account for detection probability with methods that do not accunt for this parameter. Our aim in the first chapter was to estimate occupancy and detection probability of five Cerrado endemic forest bird species (Antilophia galeata, Herpsilochmus longirostris, Syndactyla dimidiata, Hylocryptus rectirostris e Basileuterus leucophrys), using single-season occupancy modeling. We evaluated hypotheses related to forest cover (NDVI – Normalized Difference Vegetation Index, and NDVI Standard Deviation) and to the landscape composition (amount of forest, native and non-native surrounding vegetation). We conducted 589 point counts surveys at a total of 310 points in 59 sites within gallery forests during September to December from 2011 to 2013. Model-averaged occupancy estimates (ψ) ranged from 0.33 to 0.75, and detection probability (p) was less than one (0.29-0.71) for all species. Forest cover (NDVI in a 100-m buffer) was an important predictor variable and occupancy probability increased with NDVI values for three bird species. Landscape composition variables had a weak effect on occupancy probabilities. NDVI is an indirect measure of primary production and sites with higher NDVI values might have more resources available to birds. Considering this, in a local scale, the effect of habitat quality on birds’ occupancy may be more important than the amount of available habitat. Our aim in the second chapter was to assess hypotheses related to bird species abundance across the geographic distribution - centroid-periphery and habitat suitability, and to local variables - forest amount and forest cover (NDVI – Normalized Difference Vegetation Index) in a 1km buffer around survey points. We expected to find a negative relationship between species abundance and the distance to the distribution centroid and a positive relationship with forest amount and forest cover. We estimate a suitability index using program MAXENT, considering bioclimatic variables. The mean abundance was 5.22 ± 0.72 to Helmeted Manakin, 2.98 ± 0.88 to White-striped Warbler and 4.62 ± 0.71 to Larged-billed Antwren. We found significant relationships with the variables considered just to White-striped Warbler. Contrary to our expectations, species abundance decreased with increasing forest amount and increased with distance to the distribution centroid. Regarding habitat suitability the relationship with species abundance was positive, abundance increased in more suitable sites. Thus, we found that at least for one bird species, abundance probably increase towards the periphery of the distribution in areas of suitable climatic conditions. Our aim in the third chapter was to understand the effect of detectability on the species distribution modeling and compare approaches that assume p=1 (MAXENT and BIOMOD) with single-season occupancy models that account for imperfect detection. We modeled the geographic distribution of five Cerrado endemic forest birds species (Chapter 1), with different detection (p=0.51 to 0.74) and occupancy probability (ψ=0.28 to 0.89), using all three approaches. We compared the predictive performance between occupancy models and the others by calculating the relative performance of each approach considering the AUC (Area Under the Curve-ROC) and the TSS (True Skill statistic). Contrary to our expectations occupancy models showed the worst predictive performance with a significant difference between these models and the others, considering AUC and TSS accuracy measures. Possible explanations for these results can be the poor quality of the validation data and the choice of the accuracy method to compare among the approaches. Our results showed that different approaches may result in distinct predictions, and it was evident when presence-absence models were compared with presence-only models.

Few studies have evaluated the efficiency of methods for sampling ants, especially in regions with highly variable vegetation physiognomies such as the Cerrado region of central Brazil. Here we compared three methods to collect ground-dwelling ants: pitfall traps, sardine baits, and the Winkler litter extractor. Our aim was to determine which method would be most appropriate to characterize the ant assemblages inhabiting different vegetation types. More species were collected with pitfall traps and with the Winkler extractor than with sardine baits. Pitfall traps collected more species in the cerrado (savanna) physiognomies, particularly in those with a poor litter cover, whereas the Winlker extractor was more efficient in the forest physiognomies, except the one subject to periodic inundations. There was a low similarity in species composition between forest and cerrado physiognomies, and this pattern was detected regardless of the method used to sampling ants. Therefore, even the use of a single, relatively selective method of collection can be enough for studies comparing highly distinct habitats and/or conditions. However, if the purpose of the sampling is to produce a more thoroughly inventory of the ant fauna, we suggest the use of a combination of methods, particularly pitfall traps and the Winkler extractor. Therefore, the Ants of the Leaf-Litter (ALL) Sampling Protocol appear to be an adequate protocol for sampling ants in the highly-threatened Brazilian cerrado biome.

The brown-nosed coati (Nasua nasua) is a carnivorous species found in all the Brazilian biomes, some of which are endangered areas. The aim of this work was to determine the habitat use and selection, home range and core area of N. nasua in the Cerrado biome, central region of Tocantins, Brazil. The study was carried out in an area of approximately 20 000ha from May 2000 to July 2002. A total of seven box traps were placed in the area for 13 months, three of 11 captured animals were followed and monitored by radio-tracking during 13 months. The monitoring was conducted once a day, three times a week using a car and walking through the study area (radio-tracking and visual contact). The results demonstrate that these three males used more frequently the gallery forest formation, followed by cerrado and wetlands. The use of gallery forest by these animals indicated an habitat selection (Proportion test, z=12.98, p<0.01). Besides, adult males used the gallery forest more frequently (Fisher's exact test, p<0.01) and wetlands less frequently (Fisher's exact test, p<0.01) than juvenile males, without significant differences between animal ages for cerrado percentage of habitat use. Besides, results also showed a gallery forest selection by adult (Proportion test z=13.62, p<0.01) and juvenile (Proportion test z=2.68, p<0.01) males, and a wetland selection by the juvenile male (Proportion test z=3.90, p<0.01). The home ranges varied from 2.20 to 7.55km2 for the Minimum Convex Polygon 100% (MCP 100%) and from 4.38 to 13.32km2 for the Harmonic Mean 95% (HM 95%). The smallest home range overlap occurred between the adult males (Nm1 and Nm3), and the greatest between the juvenile Njm2 and the adult Nm1. The average of the core area (HM 75%) for the three monitored animals represented 21.29% of the home range calculated with HM 95%. No overlap between core areas was observed for adult males, but, it was an overlap between the core area of the juvenile male and its band with that of the two adult males. The present study provides new data on core area size and frequency habitat use by adult and juvenile males of N. nasua in the Brazilian Cerrado, that may support conservation efforts.

Ecological communities are dynamic systems that vary within and across years. In streams, disturbance by spates and the emergence of adult insects during the rainy summer contrast with more stable conditions in the dry winter and can potentially generate distinct and repeatable community states across years. However, demographic stochasticity and the legacies of previous spates may hamper the full attainment of characteristic community states associated with seasons. We developed an attractor domain model encapsulating these factors and hypothesised: (1) partially distinct rainy (summer) and dry (winter) communities. High benthic dynamism during the rainy period should cause higher inter‐annual variability, leading to (2) higher temporal β diversity among rainy periods than among dry periods. Historical effects (e.g., demographic stochasticity and disturbance by spates) should accumulate over the years and lead to (3) increased variation in community structures sampled further apart in time; furthermore, (4) this increase in variation should be higher among rainy than among dry communities. We used data of stream macroinvertebrates (mostly insects) in a subtropical basin in Brazil to evaluate inter‐annual variation using rank‐concordance statistics of the most common species and dissimilarity using all species. For each stream site, samples obtained in the two seasons tended to show distinct community structure using relative abundance data but were much less distinct using species composition (presence–absence). Temporal β diversity was higher among rainy than among dry seasons. The β diversity of both seasons increased with time, although this increase was 2–3 times greater during the rainy season. Our results support a model in which rainy (summer) communities are disrupted by the high dynamism caused by spates and the emergence of adult insects. The low intensity of these two factors during dry (winter) periods allows local environmental conditions to drive community structures toward a less variable, recurrent attractor state. However, the increase in β diversity with time indicates that the legacy effects of previous disturbances and demographic stochasticity preclude the full attainment of a definite stable state and that only a domain of states is approached.

Estimation of evapotranspiration using remote sensing is a promising and low-cost alternative, but there is a lack of studies to calibrate the algorithm for different crops and atmospheric conditions. In this context, the objective of the study was to evaluate the efficiency of the SAFER algorithm in estimating evapotranspiration of corn crops (ETa) in three different sources of surface albedo. The study was carried out in a corn (cultivar AG8700) production (March to Jully) area irrigated by central pivot in Itaberaí-GO, Brazil, in 2021. The region's climate is characterized as Aw, with two well-defined seasons, dry winter and rainy summer, and the soil was classified as Red Oxisol of medium texture. Images from a multispectral and thermal camera model MicaSense Altum and albedo images from the Landsat 8 (each 16 days) and Sentinel 2A (each 10 days) satellites were used to estimate the ETa using the SAFER algorithm. These data were compared with ETc (Crop evapotranspiration) obtained by FAO, Embrapa and climatological water balance methods based on statistical indices. In general, the best correlation with standard methods was the Drone method, mainly the FAO and BHC methods. On average, the EQM (mean square error) was less than 0.22 mm day-1. The agreement index ranged from 0.84 to 0.91. The largest errors were observed in phase III, due to contamination of albedo and NDVI pixels caused by screwing. This error was greater for the DroneLand and DroneSent methods. On average the EQM and EMA (mean absolute error) were close to 1 mm day-1, the confidence index was below 0.74 for all methods. Thus, the use of images from multispectral and thermal cameras proved to be a good tool for estimating evapotranspiration. Corn crop flowering interferes with the estimated values of NDVI and surface albedo, leading to greater underestimation. However, when drone images are used to calculate the three SAFER variables, this effect is mitigated. ETa estimation by remote sensing is not recommended for the reproductive phase of corn crop.

Forage production in the Cerrado is based on well-defined seasons: a rainy summer, and a dry winter. To define strategies that minimize the seasonality of forage production, responses in growth and biomass accumulation of five irrigated forages were evaluated during winter. The experimental design was randomized blocks, in a split plot arrangement, with five replicates, five forages in the plots (three of Panicum maximum - Mombasa, Tanzania, and Masai; two of Brachiaria brizantha - piatã and MG5), and five cuts in the subplots made from July to October 2016. Forages were cultivated with centre-pivot irrigation and the water level was defined according to the reference evapotranspiration determined through a Class A pan evaporation method, 0.8 kc, and two-day irrigation shifts. The number of shoots, leaves/tiller, leaves/plant, fresh leaf and stem biomass, dry leaf and stem biomass, fresh leaf mass/fresh stem mass ratio, dry leaf mass/dry stem mass ratio, and biomass accumulated in the five cuts were calculated. Irrigated forage during winter in the Goiás’ Cerrado showed satisfactory growth, reaching a lower plant height between cuts than those reported in the literature. Among the Panicum grasses, Mombasa grass stood out, and MG was superior to piatã grass. Highlights The forages Panicum maximum - Mombasa, Tanzania, and Masai -; and Brachiaria brizantha - piatã and MG5 -, presented satisfactory responses in growth and biomass accumulation in an irrigated culture during winter in the Goiás’ Cerrado. The Mombasa grass stood out among the forage of the genus Panicum and MG5 in the Brachiaria. The Mombasa and Brachiaria MG5 grasses are recommended for cultivation of irrigated forage during the winter in the Goiás’ Cerrado.

Studies on nest-site selection can reveal aspects of habitat requirements of the target species, and can be useful to infer about how habitat changes can affect local populations. The Helmeted Manakin, Antilophia galeata, is a piprid that inhabits mainly the humid gallery forests that occur along watercourses of the savanna-like Cerrado biome from central South America, and like most tropical forest understory passerines, it is poorly known under a nest-site selection perspective. Here we provide nest-site selection assessment based on nine variables for a population of the Helmeted Manakin from southeast Brazil. We found that females strongly selected Miconia nervosa (Melastomataceae) as a nesting plant species. Further, we demonstrated that the presence of nests was positively associated with canopy cover and with the occurrence of the endangered jussara palm trees, Euterpe edulis. These results suggest that the Helmeted Manakin is specialized in reproducing in mature and well-preserved gallery forest tracts. Gallery forests are narrow stripes of riparian vegetation from the endangered Cerrado domain, and here we showed that even in these linear habitats, the Helmeted Manakin can seek for specific portions for nesting. This is one of the few studies reporting nest-site specialization in a Neotropical forest-dwelling passerine.

Fimicolous organisms are those that can grow on dung. These substrates offer conditions that favour colonization by microorganisms, such as high nutrient and moisture content and an alkaline-neutral pH that is especially advantageous in arid/desertic regions. There are about 250 species of myxomycetes known from Brazil, which are distributed in all geographic regions and biomes, obtained mainly from plant-derived substrates. However, there are some reports of fimicolous myxomycetes in Brazil. In this study, we expand this knowledge with new records of fimicolous myxomycetes in multiple Brazilian biomes. Between 2017 and 2018, horse and cattle dung samples were collected in municipal areas in the State of Goiás (Cerrado biome): Pirenópolis, Goiás, and Porangatu; and the State of Mato Grosso (Pantanal biome): Poconé. Samples were incubated in moist chambers and monitored for four months. Myxomycetous fructifications were observed, photographed under stereo and light microscopes, and morphologically identified. Vouchers were deposited at the HUEG Herbarium. A total of five species of myxomycetes were recorded: &lt;em&gt;Arcyria cinerea and &lt;em&gt;Physarum viride (Pirenópolis), &lt;em&gt;P. cinereum (Goiás City), &lt;em&gt;P. melleum&lt;/em&gt; (Porangatu), and &lt;em&gt;Perichaena corticalis&lt;/em&gt; (Poconé). They represent the first records of fimicolous myxomycetes from the Brazilian Cerrado and Pantanal biomes. Additionally, &lt;em&gt;P. melleum&lt;/em&gt; was reported as fimicolous for the first time in Brazil and the second time in the world; &lt;em&gt;P. corticalis&lt;/em&gt; was reported for the first time in midwest region as well as for the first time as fimicolous in Brazil; and &lt;em&gt;P. viride&lt;/em&gt; was reported for the first time as fimicolous in the world.

Buriti (Mauritia flexuosa L.f.), a Brazilian native palm, is widely used by many ethnic groups. In central Brazil, a traditional community of African descendants (maroons), known as the Kalunga, utilize all the native palm species of the region. Buriti is the most important palm species for the Engenho II community of Kalungas, localized in the municipality of Cavalcante, state of Goias. Leaves are used for construction, household utensils, fodder, and medicine. Forests and wetlands of the Brazilian Cerrado are rapidly being converted to pastures and agriculture. Ethnobotanical studies of plant resources may aid in their conservation and also improve the lives of the local inhabitants. The genus Mauritia is comprised of solitary palms, with tall, robust, erect stems and palmate leaves. Two species are recognized, one of which is widely distributed throughout wet areas in northern South America, east of the Andes and just reaching Trinidad (Mauritia flexuosa L.f.) (Henderson et al. 1995). The other is more narrowly distributed in the Amazon region (Mauritia carana Wallace) (Henderson et al. 1995). The common name buriti is derived from dembyriti, a word from the native Indian language Tupi-Guarani, and signifies “a palm tree that oozes liquid.” Other common names for this majestic palm include aeta, aguaje, bariti, boriti, buriti palm, canaguche, caranda-guacu, carandai-guacu, carandai-guazu, chomiya, coqueiro-buriti, ideui, ite, mariti, meriti, miriti, morete, moriche, moriti, muriti, palma real, palmeira-buriti, palmeira-dos-brejos (Cymerys et al. 2005; Lorenzi et al. 2010; Martins et al. 2010a). Buriti frequently occurs at low elevations, forming large populations on river banks and lake margins, around water sources, and in inundated or humid areas. These buriti populations are known in Brazil as “veredas” (Ribeiro and Walter 2008) and are ecological indicators of the presence of surface water. In Brazil, buriti is the most widespread of all palm trees, occurring in the Amazon region, Cerrado, Caatinga, and Pantanal (Henderson et al. 1995; Lorenzi et al. 2010). In the Cerrado biome, the buriti palms grow spontaneously in the veredas, surrounded by shrubby and herbaceous plant communities. They also commonly inhabit inundated gallery forest habitats (Ribeiro and Walter 2008). These palms thrive in flat terrain with humid soils that permit surface water to accumulate (Reatto et al. 2008). Brazilian ethnobotanical studies of palms have focused mostly on indigenous, ribeirinhos (rivermargin dwellers of mixed ethnicity), and seringueiros (itinerant rubber collectors) (e.g., Campos and Ehringhaus 2003; Kahn 1988). A few ethnobotanical studies have been conducted in maroon communities in Brazil (Barroso et al. 2010; Crepaldi and Peixoto 2010; Silva and Freitas 2008). Notes on Economic Plants