Determining the Distribution of QoI Fungicide-Resistant Cercospora sojina on Soybean from Indiana.

Frogeye leaf spot (FLS) is a foliar disease of soybean (Glycine max) caused by Cercospora sojina. Application of fungicide products that contain quinone outside inhibitor (QoI) active ingredients has been one of the major tools used in the management of this disease, but, since 2010, QoI-resistant C. sojina isolates have been confirmed in over 20 states in the United States, including Indiana. In summer 2019 and 2020, 406 isolates of C. sojina were collected from 32 counties across Indiana and screened for QoI resistance using a PCR-restriction fragment length polymorphism (RFLP) method. An in vitro fungicide sensitivity test was also performed on a subset of isolates to evaluate their sensitivity to three QoI fungicides: azoxystrobin, pyraclostrobin, and picoxystrobin. A discriminatory dose of picoxystrobin was established as 1 µg/ml by testing five concentrations (0.001, 0.01, 0.1, 1, and 10 µg/ml). QoI-resistant isolates were found in 29 counties, and 251 of the 406 isolates (61.8%) were confirmed to be resistant to QoI fungicides based on PCR-RFLP results. Partial nucleotide sequences of the cytochrome b gene from four resistant and four sensitive isolates corroborated the presence and absence, respectively, of the G143A mutation. Results from the sensitivity assays with discriminatory doses of azoxystrobin (1 µg/ml) and pyraclostrobin (0.1 µg/ml) also supported the findings from the PCR-RFLP assay, because all QoI-resistant isolates were inhibited less than 50% relative to a no-fungicide control when exposed to these doses. Resistant isolates harboring the G143A mutation also exhibited resistance to picoxystrobin. The effective concentrations to inhibit mycelial growth by 50% relative to the nonamended control (EC50) in QoI-sensitive isolates ranged from 0.087 to 0.243 µg/ml, with an overall mean of 0.152 µg/ml, while EC50 values in QoI-resistant isolates were established as >10 µg/ml for picoxystrobin. Results from this study indicated that QoI-resistant C. sojina isolates are spread throughout Indiana and exhibit cross-resistance to QoI fungicides.

Identification of Quinone Outside Inhibitor Fungicide-Resistant Isolates of Parastagonospora nodorum from Illinois and Kentucky.

Stagonospora leaf and glume blotch, caused by Parastagonospora nodorum, is a major disease of winter wheat (Triticum aestivum) in the United States capable of significantly reducing grain yield and quality. Pathogens such as P. nodorum that overwinter in crop residue are often an increased concern in cropping systems that utilize no-till farming. In addition, the lack of wheat cultivars with complete resistance to P. nodorum has led to the reliance on foliar fungicides for disease management. Quinone outside inhibitor (QoI) fungicides (Fungicide Resistance Action Committee group 11) are one of the major classes used to manage foliar diseases in wheat. Use of the QoI class of fungicides tends to select isolates of fungal pathogens with resistance due to mutations in the fungal cytochrome b gene. Isolates of P. nodorum were collected from Illinois in 2014 and Kentucky in 2018, 2019, and 2020. Amplification and sequencing of a segment of the cytochrome b gene from these isolates revealed a mutation at codon 143 that confers a change from glycine to alanine in the amino acid sequence (known as the G143A mutation). In vitro plate assays and greenhouse trials were used to confirm and characterize the QoI resistance caused by the G143A mutation. The frequency of the tested isolates with the G143A mutation was 46% (57 of 123 isolates) and 5% (3 of 60 isolates) for Kentucky and Illinois, respectively. This research is the first to identify the G143A mutation in P. nodorum isolates with resistance to QoI fungicides in Illinois and Kentucky.

Reduction of pesticide application via real-time precision spraying.

Farmers focus on reducing the cost of production and aim to increase profit. The objective of this study was to quantify the reduction of pesticides applied to soybean (Glycine max (L.) Merrill) and maize (Zea mays L.) crops in several stages of the production cycle using a site-specific spraying application based on real-time sensors in the Brazilian Cerrado region. The sprayers were equipped with a precision spraying control system based on a real-time sensor. The spraying operations were performed not only for herbicide, but also for fungicide and insecticides applications. The maps recorded the percentage of the spray boom when the application was turned on (on/off spray system) with nozzle-to-nozzle control. The precision spraying system based on real-time sensors reduced the volume of pesticides (including herbicides, insecticides, and fungicides) applied to soybean and maize crops. There was a more significant reduction in the volume of pesticides applied post-emergence of the crops in the initial stages of soybean and maize when the crops had less leaf area or less foliage coverage between the rows. The cost reduction achieved using this technology was 2.3 times lower than the cost associated with pesticide application over the entire area using a conventional sprayer. Under the experimental conditions, there were no differences in the average crop yield, compared to the historical productivity of soybean and maize crops by applying this technology because the recommended doses were not affected and the site of application was limited to points where the presence of plants was present was detected.

Identification of Septoria glycines Isolates from Soybean with Resistance to Quinone Outside Inhibitor Fungicides.

Brown spot, caused by Septoria glycines, is a common foliar disease of soybean (Glycine max). Applications of fungicide products that contain quinone outside inhibitor (QoI) active ingredients to soybean fields have contributed to the selection and development of QoI-resistant populations of S. glycines. We investigated the molecular mechanisms of QoI-resistance in these populations through targeted analysis of the cytochrome b gene. Isolates of S. glycines collected from several soybean fields over different seasons varied in sensitivity to QoI fungicides. Characterization of the cytochrome b gene revealed a mutation that changed an amino acid from glycine to alanine at codon 143 - one that is generally associated with QoI fungicide resistances. A PCR assay was developed that allowed successful discrimination of QoI-sensitive and -resistant isolates based on the G143A mutation. Results of this study demonstrated that 47.5% of S. glycines isolates tested were resistant to QoI fungicides. Accurate monitoring of this mutation will help slow the spread of QoI resistance and will be important for fungicide resistant management in this pathosystem.

Reduction of Pythium Damping-Off in Soybean by Biocontrol Seed Treatment.

Pythium spp. is one of the major groups of pathogens that cause seedling diseases on soybean, leading to both preemergence and postemergence damping-off and root rot. More than 100 species have been identified within this genus, with Pythium irregulare, P. sylvaticum, P. ultimum var ultimum, and P. torulosum being particularly important for soybean production given their aggressiveness, prevalence, and abundance in production fields. This study investigated the antagonistic activity of potential biological control agents (BCAs) native to the U.S. Midwest against Pythium spp. First, in vitro screening identified BCAs that inhibit P. ultimum var. ultimum growth. Scanning electron microscopy demonstrated evidence of mycoparasitism of all potential biocontrol isolates against P. ultimum var. ultimum and P. torulosum, with the formation of appressorium-like structures, short hyphal branches around host hyphae, hook-shaped structures, coiling, and parallel growth of the mycoparasite along the host hyphae. Based on these promising results, selected BCAs were tested under field conditions against six different Pythium spp. Trichoderma afroharzianum 26 used alone and a mix of T. hamatum 16 + T. afroharzianum 19 used as seed treatments protected soybean seedlings from Pythium spp. infection, as BCA-treated plots had on average 15 to 20% greater plant stand and vigor than control plots. Our results also indicate that some of these potential BCAs could be added with a fungicide seed treatment with minimum inhibition occurring, depending on the fungicide active ingredient. This research highlights the need to develop tools incorporating biological control as a facet of soybean seedling disease management programs. The harnessing of native BCAs could be integrated with other management strategies to provide efficient control of seedling diseases.

The adaptive challenge of extreme conditions shapes evolutionary diversity of plant assemblages at continental scales.

The tropical conservatism hypothesis (TCH) posits that the latitudinal gradient in biological diversity arises because most extant clades of animals and plants originated when tropical environments were more widespread and because the colonization of colder and more seasonal temperate environments is limited by the phylogenetically conserved environmental tolerances of these tropical clades. Recent studies have claimed support of the TCH, indicating that temperate plant diversity stems from a few more recently derived lineages that are nested within tropical clades, with the colonization of the temperate zone being associated with key adaptations to survive colder temperatures and regular freezing. Drought, however, is an additional physiological stress that could shape diversity gradients. Here, we evaluate patterns of evolutionary diversity in plant assemblages spanning the full extent of climatic gradients in North and South America. We find that in both hemispheres, extratropical dry biomes house the lowest evolutionary diversity, while tropical moist forests and many temperate mixed forests harbor the highest. Together, our results support a more nuanced view of the TCH, with environments that are radically different from the ancestral niche of angiosperms having limited, phylogenetically clustered diversity relative to environments that show lower levels of deviation from this niche. Thus, we argue that ongoing expansion of arid environments is likely to entail higher loss of evolutionary diversity not just in the wet tropics but in many extratropical moist regions as well.

How deregulation, drought and increasing fire impact Amazonian biodiversity.

Biodiversity contributes to the ecological and climatic stability of the Amazon Basin1,2, but is increasingly threatened by deforestation and fire3,4. Here we quantify these impacts over the past two decades using remote-sensing estimates of fire and deforestation and comprehensive range estimates of 11,514 plant species and 3,079 vertebrate species in the Amazon. Deforestation has led to large amounts of habitat loss, and fires further exacerbate this already substantial impact on Amazonian biodiversity. Since 2001, 103,079-189,755 km2 of Amazon rainforest has been impacted by fires, potentially impacting the ranges of 77.3-85.2% of species that are listed as threatened in this region5. The impacts of fire on the ranges of species in Amazonia could be as high as 64%, and greater impacts are typically associated with species that have restricted ranges. We find close associations between forest policy, fire-impacted forest area and their potential impacts on biodiversity. In Brazil, forest policies that were initiated in the mid-2000s corresponded to reduced rates of burning. However, relaxed enforcement of these policies in 2019 has seemingly begun to reverse this trend: approximately 4,253-10,343 km2 of forest has been impacted by fire, leading to some of the most severe potential impacts on biodiversity since 2009. These results highlight the critical role of policy enforcement in the preservation of biodiversity in the Amazon.

Variable-rate in corn sowing for maximizing grain yield.

Sowing density is one of the most influential factors affecting corn yield. Here, we tested the hypothesis that, according to soil attributes, maximum corn productivity can be attained by varying the seed population. Specifically, our objectives were to identify the soil attributes that affect grain yield, in order to generate a model to define the optimum sowing rate as a function of the attributes identified, and determine which vegetative growth indices can be used to predict yield most accurately. The experiment was conducted in Chapadão do Céu-GO in 2018 and 2019 at two different locations. Corn was sown as the second crop after the soybean harvest. The hybrids used were AG 8700 PRO3 and FS 401 PW, which have similar characteristics and an average 135-day cropping cycle. Tested sowing rates were 50, 55, 60, and 65 thousand seeds ha-1. Soil attributes evaluated included pH, calcium, magnesium, phosphorus, potassium, organic matter, clay content, cation exchange capacity, and base saturation. Additionally, we measured the correlation between the different vegetative growth indices and yield. Linear correlations were obtained through Pearson's correlation network, followed by path analysis for the selection of cause and effect variables, which formed the decision trees to estimate yield and seeding density. Magnesium and apparent electrical conductivity (ECa) were the most important soil attributes for determining sowing density. Thus, the plant population should be 56,000 plants ha-1 to attain maximum yield at ECa values > 7.44 mS m-1. In addition, the plant population should be 64,800 plants ha-1 at values < 7.44 mS m-1 when magnesium levels are greater than 0.13 g kg-1, and 57,210 plants ha-1 when magnesium content is lower. Trial validation showed that the decision tree effectively predicted optimum plant population under the local experimental conditions, where yield did not significantly differ among populations.

First Report of Spot Blotch Caused by Bipolaris sorokiniana on Winter Rye in Kentucky.

The Kentucky distilling industry ranks as one of the state's largest industries and continues to expand. In 2017, the Kentucky distilling industry was responsible for approximately $235 million in state and local tax revenues (Coomes and Kornstein, 2019). Rye (Secale cereale L.) grains are a vital component for production of some distilled spirits. Although winter rye is produced on relatively few hectares in Kentucky currently, a recent initiative has supported expanding production to help meet the growing demand of local distilleries. University of Kentucky winter rye research field trials were visited in Caldwell and Logan Counties, KY in May 2018, and in Fayette County, KY in May 2019. Leaves were collected that had dark brown, oval to irregular-shaped lesions with definite margins and yellow halos. Symptoms were present on approximately 50% to 80% of the flag leaves, with severity ranging from 5% to 30% of the flag leaf area affected. Leaves were surface-disinfested by soaking in a 2% NaOCl solution for 1 min and rinsed twice in sterilized water and then placed in a humidity chamber (plastic bag with moist paper towels) at room temperature (approximately 24°C) to induce fungal sporulation. Seventeen single-spore isolates were obtained and stored at -80°C in 15% glycerol solution. Isolates were grown on potato dextrose agar under 12 h cycles of white light/darkness for 5 days. Colonies were gray to black. Conidia that formed were mostly straight or slightly curved, dark olivaceous brown, 3-7 septate, and 41.0-90.4 × 15.2-29.3 µm. Based on the symptoms observed on the collected leaves and these morphological characteristics similar to those described by Chang and Hwang (2000) and Manamgoda et al. (2014), the fungus was tentatively identified as Bipolaris sorokiniana (Sorokin) Shoemaker. The sequence of internal transcribed spacer regions (ITS) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were used to identify three isolates (18Bs004, 18Bs111 and 19Bs064) using primer ITS1/ITS4 (White et al. 1990) and GPD1/GPD2 (Berbee et al. 1999), respectively. The sequences were deposited in GenBank with accession numbers MT457817, MT457818 and MZ066635 for ITS sequences and MZ073644 to MZ073646 for GAPDH sequences. BLAST searches with ITS and GAPDH sequences matched 100% identity (344/344 bp and 515/515 bp for ITS and GAPDH sequences, respectively) to B. sorokiniana (GenBank accession No. MT254731 and MH844813, respectively). To prove pathogenicity, a conidial suspension (1 × 105 conidia/ml) was used to inoculate 15-day-old cultivar 'Serafino' winter rye plants in the greenhouse. Leaves of 8 plants were inoculated with 50 ml of the conidial suspension using a spray bottle. Plants were covered with a transparent plastic bag for 48 h, and symptoms were observed 10 days after inoculation. Leaf lesions, similar to those described above, were present on all inoculated plants, but no symptoms were observed on non-inoculated control plants. Bipolaris sorokiniana was reisolated from symptomatic leaves and the identity of the pathogen was confirmed based on the morphology previously described. To our knowledge, this is the first report of spot blotch caused by B. sorokiniana on winter rye in Kentucky, but B. sorokiniana has been reported on rye in the neighboring state of Virginia (Roane 2009). Kentucky produces approximately 150,000 and 4,000 ha of winter wheat (Triticum aestivum) and winter barley (Hordeum vulgare) annually, respectively, which are both known hosts of B. sorokiniana (Kumar et al. 2002). An isolate of B. sorokiniana from rye was reported by Ghazvini and Tekauz (2007) to be less virulent on barley differential lines. Further research is needed to better understand spot blotch distribution, susceptibility in winter rye cultivars, and potential yield and quality loss implications in winter rye production and end use. It is unknown how susceptible various winter rye cultivars grown in Kentucky are to spot blotch.

Liquid nitrogen fertilization on the yield and phenologic variables of narrow-row cotton / Adubação nitrogenada líquida na produtividade e variáveis fenológicas em algodoeiro adensado

Slow-release liquid nitrogen fertilizer sources have been around since 1970. However, this technique is not widely used in the field, probably due to the low cost per ton of nitrogen in the solid form. This study aimed to evaluate the combination of the conventional and slow-release nitrogen fertilization on the yield and phenological variables in a narrow-row cotton crop. Treatments consisted of the combination of the nitrogen fertilizer applied as topdressing in solid form (via soil) and pulverized in the liquid form (via urea formaldehyde - UF): 0% of solid N + 0% of liquid N (0S0L); 100% of solid N + 0% of liquid N (100S0L); 75% of solid N + 25% of liquid N (75S25L); 50% of solid N + 50% of liquid N (50S50L); 25% of solid N + 75% of liquid N (25S75L); e 0% of solid N + 100% of liquid N (0S100L). The cotton crop was phenotypically evaluated at 35, 70, and 130 DAE (Days after emergence) and at the harvest time. The variation between the source of the solid nitrogen fertilizer applied to the soil (ammonium nitrate) and the liquid Nitrogen fertilizer applied by spraying (UF) affects the phenology, physiology, and yield components of the narrow-row cotton crop. The highest yield of the narrow-row cotton crop under the experimental conditions was achieved when 25% of the dose of the solid nitrogen fertilizer was applied as topdressing via soil, and 75% of the dose of the slow-release nitrogen fertilizer was sprayed. This technique provides higher profitability of the produced cotton in relation to the conventional application of the N solid fertilizer via soil.

Fontes de fertilizantes nitrogenados líquidos de liberação lenta existem desde 1970. No entanto, esta técnica não é amplamente utilizada no campo, provavelmente devido ao baixo custo por tonelada de nitrogênio na forma sólida. Este trabalho teve como objetivo avaliar a combinação da adubação nitrogenada convencional e de liberação lenta sobre a produtividade e as variáveis fenológicas em uma cultura de algodão de fileira estreita. Os tratamentos consistiram da combinação do fertilizante nitrogenado aplicado como cobertura na forma sólida (via solo) e pulverizado na forma líquida (via uréia formaldeído - UF): 0% de N sólido + 0% de N líquido (0S0L); 100% de N sólido + 0% de N líquido (100 S); 75% de N sólido + 25% de N líquido (75S25L); 50% de N sólido + 50% de N líquido (50S50L); 25% de N sólido + 75% de N líquido (25S75L); e 0% de N sólido + 100% de N líquido (0S100L). A cultura do algodão foi avaliada fenotipicamente aos 35, 70 e 130 DAE (dias após a emergência) e no momento da colheita. A variação entre a fonte de adubação nitrogenada aplicada ao solo (nitrato de amônio) e o fertilizante nitrogenado líquido aplicado por pulverização (UF) afeta os componentes fenológicos, fisiológicos e produtivos da cultura de algodão de fileiras estreitas. O maior rendimento da cultura de algodão de linha estreita nas condições experimentais foi alcançado quando 25% da dose do fertilizante de nitrogênio sólido foi aplicado como cobertura de solo via solo, e 75% da dose do fertilizante de nitrogênio de liberação lenta foi pulverizada. Esta técnica proporciona maior rentabilidade do algodão produzido em relação à aplicação convencional do fertilizante N via solo.

Survival of Pratylenchus brachyurus under dry soil conditions.

Pratylenchus brachyurus, a root-lesion nematode, depends on host plants for growth and survival. Weeds, volunteer plants, and crop root residues may act as reservoirs for the parasite in the field, but little is known about the ability of P. brachyurus to survive in the absence of a host. This study aimed to evaluate P. brachyurus survival and infectivity in artificially and naturally infested soil under dry conditions. Two experiments were conducted, the first using artificially infested soil and the second using naturally infested soil. Soil samples were inoculated with a nematode suspension or infected root fragments. At 0, 30, 60, and 90 days post-inoculation, pots were planted with nematode-susceptible maize and soybean. Fallow pots were also analyzed. Nematode survival, infectivity, and morphology were determined 30 days after planting. P. brachyurus showed enhanced survival in soil in the presence of root fragments. However, inoculation method had no effect on the ability of surviving nematodes to infect host roots. Parasites showed signs of anhydrobiosis (C-shaped or tightly coiled body) after 90 and 120 days under dry conditions.

Freezing and water availability structure the evolutionary diversity of trees across the Americas.

The historical course of evolutionary diversification shapes the current distribution of biodiversity, but the main forces constraining diversification are still a subject of debate. We unveil the evolutionary structure of tree species assemblages across the Americas to assess whether an inability to move or an inability to evolve is the predominant constraint in plant diversification and biogeography. We find a fundamental divide in tree lineage composition between tropical and extratropical environments, defined by the absence versus presence of freezing temperatures. Within the Neotropics, we uncover a further evolutionary split between moist and dry forests. Our results demonstrate that American tree lineages tend to retain their ancestral environmental relationships and that phylogenetic niche conservatism is the primary force structuring the distribution of tree biodiversity. Our study establishes the pervasive importance of niche conservatism to community assembly even at intercontinental scales.

Evolutionary diversity in tropical tree communities peaks at intermediate precipitation.

Global patterns of species and evolutionary diversity in plants are primarily determined by a temperature gradient, but precipitation gradients may be more important within the tropics, where plant species richness is positively associated with the amount of rainfall. The impact of precipitation on the distribution of evolutionary diversity, however, is largely unexplored. Here we detail how evolutionary diversity varies along precipitation gradients by bringing together a comprehensive database on the composition of angiosperm tree communities across lowland tropical South America (2,025 inventories from wet to arid biomes), and a new, large-scale phylogenetic hypothesis for the genera that occur in these ecosystems. We find a marked reduction in the evolutionary diversity of communities at low precipitation. However, unlike species richness, evolutionary diversity does not continually increase with rainfall. Rather, our results show that the greatest evolutionary diversity is found in intermediate precipitation regimes, and that there is a decline in evolutionary diversity above 1,490 mm of mean annual rainfall. If conservation is to prioritise evolutionary diversity, areas of intermediate precipitation that are found in the South American 'arc of deforestation', but which have been neglected in the design of protected area networks in the tropics, merit increased conservation attention.

The commonness of rarity: Global and future distribution of rarity across land plants.

A key feature of life's diversity is that some species are common but many more are rare. Nonetheless, at global scales, we do not know what fraction of biodiversity consists of rare species. Here, we present the largest compilation of global plant diversity to quantify the fraction of Earth's plant biodiversity that are rare. A large fraction, ~36.5% of Earth's ~435,000 plant species, are exceedingly rare. Sampling biases and prominent models, such as neutral theory and the k-niche model, cannot account for the observed prevalence of rarity. Our results indicate that (i) climatically more stable regions have harbored rare species and hence a large fraction of Earth's plant species via reduced extinction risk but that (ii) climate change and human land use are now disproportionately impacting rare species. Estimates of global species abundance distributions have important implications for risk assessments and conservation planning in this era of rapid global change.

Evolutionary diversity is associated with wood productivity in Amazonian forests.

Higher levels of taxonomic and evolutionary diversity are expected to maximize ecosystem function, yet their relative importance in driving variation in ecosystem function at large scales in diverse forests is unknown. Using 90 inventory plots across intact, lowland, terra firme, Amazonian forests and a new phylogeny including 526 angiosperm genera, we investigated the association between taxonomic and evolutionary metrics of diversity and two key measures of ecosystem function: aboveground wood productivity and biomass storage. While taxonomic and phylogenetic diversity were not important predictors of variation in biomass, both emerged as independent predictors of wood productivity. Amazon forests that contain greater evolutionary diversity and a higher proportion of rare species have higher productivity. While climatic and edaphic variables are together the strongest predictors of productivity, our results show that the evolutionary diversity of tree species in diverse forest stands also influences productivity. As our models accounted for wood density and tree size, they also suggest that additional, unstudied, evolutionarily correlated traits have significant effects on ecosystem function in tropical forests. Overall, our pan-Amazonian analysis shows that greater phylogenetic diversity translates into higher levels of ecosystem function: tropical forest communities with more distantly related taxa have greater wood productivity.

Physical, ecological and human dimensions of environmental change in Brazil's Pantanal wetland: Synthesis and research agenda.

The Pantanal is the world's largest freshwater wetland, located in the geographical centre of South America. It is relatively well conserved, and features unique landscapes, ecosystems, and traditional cultural practices, shaped by the dynamic interaction of climatological, hydrological, geological, ecological, and anthropogenic factors. Its ecological integrity is increasingly threatened by human activities, particularly, in the wider catchment area, for example, deforestation, agricultural intensification, and construction of hydropower plants, with implications for local people's livelihoods. We present a synthesis of current literature on physical, ecological, and human dimensions of environmental change in the wetland, outline key research gaps, and discuss environmental management implications. The literature review suggests that better integration of insights from multiple disciplines is needed and that environmental management could be improved through a better grounding in traditional practices and local perspectives. We conclude with four recommendations: First, future environmental change research should build more strongly on the positive example of a small number of case studies where traditional and local knowledge of the environment was put into a dialogue with scientific knowledge and techniques. Second, we recommend a more explicit consideration of longer temporal scales (>10 years) in environmental change research, making use of oral and written histories, as well as palaeoecological techniques, to understand system responses to different magnitudes of human and climatic pressures, and ultimately, to inform future adaptation activities. Third, we suggest that enhanced stakeholder participation in conceiving and implementing research projects in the Pantanal would strengthen the practical relevance of research in addressing environmental management challenges, livelihood needs, and advocacy processes. Fourth, we call for a more systemic and integrative perspective on environmental education, which encompasses engagement activities between researchers, policy-makers, and citizens, to foster environmental awareness, scientific literacy, and public participation.

Relationship between cotton productivity and variability of NDVI obtained by landsat images / Relação entre produtividade do algodoeiro e variabilidade do NDVI obtido por imagens do landsat

The availability of satellite images has generated a large number of regional and global studies on vegetation mapping. Such studies have related the growth parameters, nutrient status, physiological responses, and water resources to the yield of agricultural crops or native vegetation. The NDVI (Normalized Difference Vegetation Index) is associated with parameters of growth and yield with readings at several moments of the crop cycle. The objective of this work was to correlate the yield and variability of the NDVI in cotton fields by analyzing Landsat satellite images acquired over nine growing seasons. The study involved the analysis of 101 cotton production fields located in West-Central Brazil. One Landsat image was used during each crop cycle, and the average yield was computed based on total fiber harvested at each field. The fiber yield ranged from 393 to 2,030 kg ha-1, and its correlation with NDVI was 0.37. The coefficient of variation (CV) had a negative correlation with yield, approximating -58.1 kg ha-1 for every one percent increment of the CV. The CV explained the yield variability over the cotton fields more accurately than the average absolute NDVI value.

Desde a disponibilização das imagens de satélites, tem-se gerado grande número de estudos regionais e globais para caracterizar a vegetação. Esses estudos têm relacionado parâmetros de crescimento, nutricionais, fisiológicos, hídricos e produtividade das culturas agrícolas ou vegetação nativa. O NDVI (Normalized Difference Vegetation Index) é associado com parâmetros de crescimento e produtividade do algodoeiro com leituras em vários momentos do ciclo. O objetivo desse trabalho foi relacionar a variabilidade do NDVI em campos de produção de algodão e a produtividade pelo uso de imagens do satélite Landsat ao longo de nove safras. O estudo foi desenvolvido com análise de 101 campos de produção localizados na região central do Brasil. Foi utilizada uma imagem durante o ciclo da cultura e a produtividade média obtida. A produtividade de fibra variou de 393 a 2.030 kg ha-1 e a correlação com NDVI foi de 0,37. O coeficiente de variação teve correlação negativa, com queda na produtividade em -58,1 kg ha-1 ao aumentar um ponto percentual. O coeficiente de variação explicou melhor a variabilidade da produtividade dos talhões que o NDVI médio.

Plant diversity patterns in neotropical dry forests and their conservation implications.

Seasonally dry tropical forests are distributed across Latin America and the Caribbean and are highly threatened, with less than 10% of their original extent remaining in many countries. Using 835 inventories covering 4660 species of woody plants, we show marked floristic turnover among inventories and regions, which may be higher than in other neotropical biomes, such as savanna. Such high floristic turnover indicates that numerous conservation areas across many countries will be needed to protect the full diversity of tropical dry forests. Our results provide a scientific framework within which national decision-makers can contextualize the floristic significance of their dry forest at a regional and continental scale.

Occurrence of an invasive coral in the southwest Atlantic and comparison with a congener suggest potential niche expansion.

Tubastraea tagusensis, a coral native to the Galapagos Archipelago, has successfully established and invaded the Brazilian coast where it modifies native tropical rocky shore and coral reef communities. In order to understand the processes underlying the establishment of T. tagusensis, we tested whether Maxent, a tool for species distribution modeling, based on the native range of T. tagusensis correctly forecasted the invasion range of this species in Brazil. The Maxent algorithm was unable to predict the Brazilian coast as a suitable environment for the establishment of T. tagusensis. A comparison between these models and a principal component analysis (PCA) allowed us to examine the environmental dissimilarity between the two occupied regions (native and invaded) and to assess the species' occupied niche breadth. According to the PCA results, lower levels of chlorophyll-a and nitrate on the Atlantic coast segregate the Brazilian and Galapagos environments, implying that T. tagusensis may have expanded its realized niche during the invasion process. We tested the possible realized niche expansion in T. tagusensis by assuming that Tubastraea spp. have similar fundamental niches, which was supported by exploring the environmental space of T. coccinea, a tropical-cosmopolitan congener of T. tagusensis. We believe that the usage of Maxent should be treated with caution, especially when applied to biological invasion (or climate change) scenarios where the target species has a highly localized native (original) distribution, which may represent only a small portion of its fundamental niche, and therefore a violation of a SDM assumption.