RESUMEN Los estudios epidemiológicos sobre los efectos de la contaminación del aire en México a menudo utilizan las concentraciones ambientales de los monitores más cercanos al hogar como indicadores de exposición, sin embargo, este enfoque ignora los gradientes espaciales de los contaminantes y asume que las personas no tienen movilidad dentro de la ciudad. Nuestro objetivo fue desarrollar modelos espaciales y temporales de alta resolución para predecir la exposición a largo plazo a PM2.5 y NO2 en una población de ~16 500 participantes de un estudio de Cohorte de Maestras Mexicanas (ESMaestras). Geocodificamos las direcciones de la casa y el trabajo de las participantes. Utilizando información de fuentes secundarias sobre variables geográficas y meteorológicas, así como otros contaminantes, ajustamos dos modelos aditivos generalizados para predecir las concentraciones mensuales de PM2.5 y NO2 en el periodo 2004-2019. Los modelos se evaluaron mediante validación cruzada de 10 iteraciones. Ambos mostraron una alta precisión predictiva con datos fuera de la muestra y no sobreajuste (CV RMSE = 0.102 para PM2.5 y CV RMSE = 4.497 para NO2). Los participantes estuvieron expuestos a un promedio mensual de 24.38 (6.78) µg m-3 de PM2.5 y 28.21 (8.00) ppb de NO2 durante el periodo de estudio. Estos modelos ofrecen una alternativa prometedora para estimar la exposición a PM2.5 y NO2 con alta resolución espaciotemporal para estudios epidemiológicos en la región del Valle de México.

ABSTRACT Epidemiological studies on air pollution in Mexico often use the environmental concentrations of pollutants as measured by monitors closest to the home of participants as exposure proxies, yet this approach does not account for the space gradients of pollutants and ignores intra-city human mobility. This study aimed to develop high-resolution spatial and temporal models for predicting long-term exposure to PM2.5 and NO2 in ~16 500 participants from the Mexican Teachers’ Cohort study. We geocoded the home and work addresses of participants, and used secondary source information on geographical and meteorological variables as well as other pollutants to fit two generalized additive models capable of predicting monthly PM2.5 and NO2 concentrations during the 2004-2019 period. Both models were evaluated through 10-fold cross-validation, and showed high predictive accuracy with out-of-sample data and no overfitting (CV-RMSE = 0.102 for PM2.5 and CV-RMSE = 4.497 for NO2). Participants were exposed to a monthly average of 24.38 (6.78) µg m-3 of PM2.5 and 28.21 (8.00) ppb of NO2 during the study period. These models offer a promising alternative for estimating PM2.5 and NO2 exposure with high spatiotemporal resolution for epidemiological studies in the Mexico City Metropolitan Area.

Abstract Here, we evaluate the relationships between the infestation rates of five monogenean parasites species with the dry and wet seasons, with the organic and inorganic parameters of the water of two rivers: the Jacaré-Pepira and Jacaré-Guaçú, and with the condition factors of its fish hosts: Serrasalmus maculatus and Astronotus crassipinnis, in the state of São Paulo, southeastern Brazil. Fish were collected between January and December 2017. Anacanthorus serrasalmi, Amphithecium speirocamarotum and Gussevia asota had higher abundance rates (Student’s t test, p ≤ 0.05) in the wet season. Gussevia asota had its abundance negatively correlated to nitrate in the Jacaré-Pepira River and with total nitrogen and potassium in the Jacaré-Guaçú River. Regarding the fish hosts condition factors, was observed a positive correlation with the abundances of G. asota in the Jacaré-Guaçú River, and with A. serrasalmi in the Jacaré-Pepira River. In general, wet season favored an increasing in the infestation rates of the monogeneans parasites in their host species, mainly in the river considered as the most polluted, the Jacaré-Guaçú River. Of the five parasites species analyzed in this study, only Gussevia astronoti and Rhinoxenus piranhus had no interaction with seasonality, river water variables, or fish host condition factors. On the other hand, G. asota had interactions both with water parameters (nitrate and total nitrogen) and with the hosts condition factors, which reflected in the abundance and intensity rates, showing itself as a species sensitive to changes in the environment and, therefore, that can be considered as a bioindicator organism.

Resumo Aqui, nós avaliamos as relações entre as taxas de infestação de cincos espécies de parasitos monogenéticos em relação aos períodos seco e chuvoso, aos parâmetros orgânicos e inorgânicos da água de dois rios: Jacaré-Pepira e Jacaré-Guaçú, e em relação aos fatores de condição das espécies de peixes hospedeiras: Serrasalmus maculatus e Astronotus crassipinnis, no estado de São Paulo, sudeste do Brasil. Os peixes foram coletados entre os meses de janeiro a dezembro de 2017. Anacanthorus serrasalmi, Amphithecium speirocamarotum e Gussevia asota tiveram maiores taxas de abundância (teste t de Student, p ≤ 0,05) no período chuvoso. Gussevia asota teve sua abundância negativamente correlacionada com o nitrato no rio Jacaré Pepira e com o nitrogênio total e potássio no rio Jacaré-Guaçú. Em relação ao fator de condição dos peixes, foi observado uma correlação positiva com a abundância de G. asota no rio Jacaré-Guaçú e com A. serrasalmi no rio Jacaré-Pepira. No geral, o período chuvoso favoreceu um aumento nas taxas de infestação dos parasitos monogenéticos em seus peixes hospedeiros, especialmente no rio considerado como o mais poluído, o rio Jacaré-Guaçú. Das cinco espécies de parasitos analisadas no estudo, somente Gussevia astronoti e Rhinoxenus piranhus não tiveram nenhum tipo de interação com a sazonalidade, com as variáveis das águas dos rios ou com o fator de condição dos peixes hospedeiros. Por outro lado, G. asota teve interações tanto com os parâmetros da água (nitrato e nitrogênio total) quanto com os fatores de condição dos hospedeiros, que refletiram nas taxas de abundância e de infestação, mostrando que esta espécie é sensível às mudanças no ambiente e que, portanto, pode ser utilizada como um organismo bioindicador.

Abstract Understanding patterns of freshwater fish assemblage structure is key to protect them from ongoing human-induced threats to aquatic biodiversity. Yet, studies on associations between fish assemblages and habitat are lacking from many areas of high diversity in Middle America. We assessed fish assemblage structure and environmental associations from a portion of the Lacantún River sub-basin (Usumacinta River, Chiapas, Mexico). Based on environmental data and 17,462 individuals (56 species, 46 genera, and 22 families) captured from 13 sites sampled between 2017–2019, we found that stream order, distance to the Usumacinta, forest cover, temperature, and dissolved oxygen are key to explaining assemblage composition. Four clusters were found via multivariate regression tree analysis, with stream order and dissolved oxygen as defining variables. Our findings suggest that fish communities remain spatially structured even at small scales, in association to environmental gradients among habitats.

Resumen Comprender los patrones de estructuración en los ensamblajes de peces dulceacuícolas es una clave para protegerlos de las amenazas humanas a la biodiversidad acuática. No obstante, los estudios sobre asociaciones entre ensamblajes de peces y su hábitat son aún escasos en muchas áreas de alta diversidad de América Media. Evaluamos las asociaciones entre la estructura de los ensamblajes de peces y el ambiente de una porción de la subcuenca del Río Lacantún (cuenca del Río Usumacinta, Chiapas, México). Con base en datos ambientales y un total de 17,462 individuos (56 especies, 46 géneros, y 22 familias) capturados de 13 sitios muestreados entre 2017–2019, encontramos que el orden del cauce, distancia al Usumacinta, cobertura vegetal, temperatura y oxígeno disuelto son clave para explicar la composición de los ensamblajes. Cuatro grupos se detectaron utilizando un árbol de regresión multivariada, definidos por el orden del cauce y el oxígeno disuelto como variables definitorias. Nuestros hallazgos sugieren que las comunidades de peces retienen su estructura espacial aún a pequeñas escalas, en asociación a gradientes ambientales entre hábitats.

Abstract Gradual climatic changes caused by mountains’ altitudinal variation promote alterations in the structure of ecological communities. Environmental changes are also expected according to the slope’s position in relation to the sea. In this study, we aimed to compare epiphytic pteridophyte communities along altitudinal gradients on opposite slopes in a section of the Atlantic Forest. We sampled a total of 10 sites in the montane and upper montane zones from the eastern (facing the sea) and western (facing away from the sea) slopes. A total of 1,742 individuals from 62 epiphytic species were recorded. The slopes showed similar epiphytic abundances and richness. Species richness showed a tendency to decrease with an increase in altitude on the western slope, and abundance was higher at intermediate altitudes, with no altitudinal trend in dominance. Conversely, on the eastern slope, there was no clear altitudinal pattern in richness or abundance; however, dominance increased with an increase in altitude from 1,200 to 1,800 m. Species compositions differed among altitudinal zones and between slopes. The eastern slope had lower species richness and no clear altitudinal gradient, although it was better preserved than the western one. Thus, there are differences in the community structure of epiphytic pteridophytes from the forest understory due to altitudinal variation and slope orientation, and these findings corroborate our hypotheses.

Resumo As mudanças climáticas graduais causadas pela variação altitudinal nas montanhas promovem alterações na estrutura das comunidades ecológicas. Mudanças ambientais também são esperadas de acordo com a posição das vertentes em relação ao mar. Neste estudo, nós objetivamos comparar a comunidade de pteridófitas epífitas ao longo dos gradientes altitudinais em vertentes opostas em um trecho de Floresta Atlântica. Amostramos um total de 10 sítios nas faixas montana e alto-montana das vertentes oriental (voltada para o mar) e ocidental (oposta ao mar). Um total de 1,742 indivíduos, distribuídos em 62 espécies epifíticas, foram registrados. As vertentes mostraram valores similares de abundância e riqueza epifítica. A riqueza tendeu a diminuir com o aumento da altitude na vertente ocidental; a abundância foi elevada na altitude intermediária e nenhuma tendência altitudinal na dominância foi observada. Na oriental, não houve nenhum padrão altitudinal claro na riqueza ou abundância em relação à altitude, mas um aumento na dominância de 1,200 a 1,800 m. A composição de espécies diferiu entre as faixas altitudinais e entre as vertentes. A vertente oriental teve menor riqueza e nenhum gradiente altitudinal claro, embora fosse mais preservada que a ocidental. Portanto, existem diferenças na estrutura da comunidade de pteridófitas epífitas do sub-bosque florestal devido à variação altitudinal e orientação das vertentes, e esses resultados corroboram nossas hipóteses.

Abstract Teredinids are bivalves mollusks considered the most abundant of invertebrates group of marine wood borers performing an important role in the mangrove environment. This study aimed to characterize the Teredinidae species from the Acaraú River estuary in Ceará and analyse the relationship between the mangrove plant structure and the distribution of Teredinidae, according to gradients estuaries: vertical (flooding) and horizontal (salinity). The collection of mangrove logs with Teredinidae happened in three places within the estuary (inner, median, and upper); in each area, three transects were traced in which three plots were lined off, and a total of 40 logs were collected. Teredinidae species were found and identified: Nausitora fusticula; Neoteredo reynei; Teredo turnerae; Teredo cf. bartschi; Bankia bipennata; Bankia gouldi; Lirodus massa and Lyrodus cf. bipartitus. The Lyrodus cf. bipartitus, Bankia gouldi, and Teredo cf. bartschi species were registered for the first time in Ceará. The distribution and species richness of Teredinidae were directly related to the vertical gradient (flooding) and heterogeneity of the mangrove forest habitat. The data presented here are essential for comprehending the mechanisms responsible for the distribution patterns of the Teredinidae species in the mangrove, contributing to biodiversity conservation in Ceará coastal zones.

Resumo Os teredinídeos são moluscos bivalves considerados o grupo de invertebrados mais abundante de organismos perfuradores de madeira marinha, desempenhando importante papel ecológico nos ambientes de manguezais. O objetivo do estudo foi realizar a caracterização das espécies de Teredinidae do estuário do Rio Acaraú, Ceará e analisar a relação da estrutura vegetal do bosque de mangue com a distribuição dos teredinídeos de acordo com os gradientes estuarinos: vertical (inundação) e horizontal (salinidade). A coleta dos troncos de mangue com teredinídeos aconteceu em três pontos do estuário (interior, médio e superior). Em cada ponto foram traçados três transectos nos quais, foram demarcadas três parcelas das quais foram coletados o total de 40 troncos. Foram encontradas e identificadas 8 espécies de Teredinidae: Nausitora fusticula; Neoteredo reynei; Teredo turnerae; Teredo cf. bartschi; Bankia bipennata; Bankia gouldi; Lirodus massa e Lyrodus cf. bipartitus. As espécies Lyrodus cf. bipartitus, Bankia gouldi e Teredo cf. bartschi, foram registradas pela primeira vez no estado. A distribuição e riqueza de espécies de Teredinidae estiveram diretamente relacionadas com o gradiente vertical (inundação) e heterogeneidade de hábitat do bosque de mangue. Os dados aqui apresentados serão importantes para compreensão dos mecanismos responsáveis pelos padrões de distribuição das espécies de Teredinidae nos bosques de mangues, contribuindo para a conservação da biodiversidade em zonas costeiras do Ceará.

Abstract Background: Phenotypic and functional traits of plant populations vary with environmental conditions at local and regional scales. The analysis of these traits along environmental gradients provides information on the differential response of populations to climate changes. Objective: We analyzed the leaf morphological variation of an endemic oak to identify the degree of population differentiation along an environmental gradient. Study species: Quercus mexicana Bonpl. (Fagaceae). Study site and dates: Samples were collected from 39 populations in the Sierra Madre Oriental and east of the Trans-Mexican Volcanic Belt from 2014 to 2016. Methods: We measured eight macromorphological traits in 5,507 leaves and three micromorphological traits in 228 leaves. We performed univariate and multivariate statistical analyses to assess the morphological differentiation among populations, and the relationship between variation in leaf traits and environmental variables related to temperature and water availability. Results: Populations of Q. mexicana showed leaf morphological differentiation along its distribution. Significant linear correlations were found between leaf traits and environmental variables. Smaller and thicker leaves with lower density of trichomes and smaller stomata were found in populations located in more arid regions. In contrast, larger and thinner leaves with higher trichome density and larger stomata occurred in more humid places. Conclusions: Populations of Q. mexicana are adapted to a wide range of climatic conditions. Considering the predictive future climatic changes for the region (i.e., warmer and drier conditions), Q. mexicana populations with traits better adapted to a more humid and cooler environments could be negatively affected.

Resumen Antecedentes: Los caracteres fenotípicos y funcionales de las poblaciones de plantas varían a escalas local y regional. El análisis de estos caracteres a lo largo de gradientes ambientales proporciona información sobre la respuesta diferencial de las poblaciones a cambios climáticos. Objetivo: Analizamos la variación foliar morfológica de un encino endémico para identificar el grado de diferenciación poblacional a un gradiente ambiental. Especie de estudio: Quercus mexicana Bonpl. (Fagaceae). Sitio de estudio y fechas: Se colectaron 39 poblaciones en la Sierra Madre Oriental y del este de la Faja Volcánica Transmexicana de 2014 al 2016. Métodos: Medimos ocho caracteres macromorfológicos en 5,507 hojas y tres micromorfológicos en 228 hojas. Se realizaron análisis estadísticos univariados y multivariados para evaluar la diferenciación morfológica entre poblaciones, y las relaciones entre la variación foliar y variables relacionadas con la temperatura y la disponibilidad de agua. Resultados: Las poblaciones de Q. mexicana están diferenciadas a lo largo de su distribución. Se encontraron correlaciones significativas entre caracteres foliares y variables ambientales. Hojas pequeñas y gruesas con baja densidad de tricomas y estomas pequeños se encontraron en sitios más áridos. En contraste, hojas más grandes y delgadas con mayor densidad de tricomas y estomas más grandes ocurrieron en sitios más húmedos. Conclusiones: Las poblaciones de Q. mexicana están adaptadas a un amplio intervalo de condiciones climáticas. Considerando los futuros cambios climáticos para la región (i.e., condiciones más secas y cálidas), las poblaciones de Q. mexicana con caracteres adaptados a ambientes más húmedos y fríos podrían afectarse negativamente.

Resumen Colombia presenta alta diversidad de genotipos de papa diploide (Solanum tuberosum, grupo Phureja), cultivados en un amplio rango altitudinal. El objetivo de esta investigación fue evaluar el efecto de la altitud en el rendimiento y la calidad poscosecha de cultivares mejorados de papa del grupo Phureja. Para ello, se empleó un arreglo factorial completo en bloques generalizados, cuyo primer factor fue el cultivar (Criolla Colombia, Criolla Dorada, Criolla Ocarina, Paola y Violeta) y el segundo, la localidad con altitudes contrastantes (3.200, 2.700 y 2.300 m s.n.m.). Las variables de productividad evaluadas fueron rendimiento, porcentaje por categoría comercial y número de tubérculos, mientras que las de calidad fueron gravedad específica, respuesta a fritura y, para el cultivar violeta, pigmentación en tubérculo. Se presentaron diferencias significativas en todas las variables evaluadas, por la interacción de la localidad por cultivar. Criolla Dorada fue el cultivar más estable en rendimiento entre localidades. En la localidad baja, se afectó la productividad de los cultivares Criolla Ocarina, Paola y Violeta, a diferencia de localidades con mayor altitud, donde se favoreció el rendimiento y porcentaje de papa “categoría primera” en todos los cultivares. Una mayor altitud de la localidad favoreció el número de tubérculos por sitio en Criolla Ocarina, la gravedad específica en Criolla Dorada y la pigmentación en tubérculo de Violeta, pero afectó negativamente la fritura en todos los cultivares. Teniendo en cuenta que la altitud de siembra afectó todas las variables evaluadas con diferencias por cultivar, se debe considerar esta interacción al momento de establecer cultivos de papa del grupo Phureja.

Abstract Colombia has an important diversity of diploid potatoes genotypes (Solanum tuberosum, Phureja Group) cultivated in a wide altitudinal range. The goal of this research was to evaluate the effect of planting altitude in terms of yield and postharvest quality on improved potato cultivars of the Phureja Group. A complete factorial arrangement on generalized blocks was used. The first factor was the cultivar (Criolla Colombia, Criolla Dorada, Criolla Ocarina, Paola y Violeta), and the second one the locality with contrasting altitudes (3200, 2700 y 2300 m a.s.l.). Examined productivity variables were yield, percentage by commercial category and number of tubers, while the quality variables were specific gravity, response to frying and, for the violet cultivar, tuber pigmentation. Significant differences were found in all the variables evaluated, due to the interaction between locality and cultivar. Criolla Dorada was the most stable cultivar in yield between locations. In the lower locality, the productivity of the cultivars Criolla Ocarina, Paola and Violeta was affected, in contrast to localities with higher altitude, where the yield and percentage of "first category" potato was enhanced in all cultivars. Altitude enhanced the number of tubers per site in Criolla Ocarina, specific gravity in Criolla Dorada and pigmentation in Violeta tubers, but negatively affected frying in all cultivars. Considering that planting altitude affected all the variables evaluated with differences by cultivar, this interaction should be considered when establishing potato cultivars of the Phureja group.

Abstract Background: Seedling establishment depends on the quality of the seeds and environmental conditions. Differential biomass allocation in emergent seedlings probably constitutes a relevant adaptive response of populations along environmental gradients. Questions: Are there differences in seed mass and biomass allocation in seedlings among Prosopis laevigata populations? Is this variation correlated with environmental variables? Studied species: Prosopis laevigata (Humb. & Bonpl. ex Willd.) M.C.Johnst (Fabaceae). Study site and dates: Thirteen localities along the distribution of P. laevigata in México. From 2016 to 2020. Methods: Seeds were collected from four or five mother trees per locality. Seed mass (SM) was obtained in ten seeds per mother and six functional traits indicative of biomass allocation were measured in the seedlings after 10 days of germination. Population mean values were obtained for the six traits plus SM and subjected to a principal component analysis (PCA). Population scores on the first two axis of the PCA were regressed against environmental variables from the collection localities using a stepwise regression model. Results: Populations displayed functional variation congruent with alternative biomass allocation strategies. The conservative strategy was characterized by larger seeds and seedlings with denser tissues and a higher investment in root biomass, while the opposite characterized the acquisitive strategy. Actual evapotranspiration in May, isothermality and soil water content in February were environmental variables that significantly predicted population scores on the first two axes of the PCA. Conclusion: Water availability gradients influence seed mass and seedling biomass allocation variation among P. laevigata populations.

Resumen Antecedentes: El establecimiento de las plántulas depende de la calidad de las semillas y las condiciones ambientales. El patrón de asignación de biomasa en plántulas recién emergidas es probablemente una adaptación relevante en gradientes ambientales. Preguntas: ¿Existen diferencias en masa de la semilla y asignación de biomasa de plántulas entre poblaciones de Prosopis laevigata? ¿Se correlaciona esta variación con factores ambientales? Especie de estudio: Prosopis laevigata (Humb. & Bonpl. ex Willd.) M.C.Johnst (Fabaceae). Sitio y años de estudio: Trece localidades de P. laevigata. 2016-2020. Métodos: Se colectaron semillas de cinco árboles por localidad. Se determinó la masa (MS) en diez semillas por árbol y se midieron seis rasgos funcionales en plántulas de 10 días de edad. Las medias por población para los siete atributos se analizaron mediante componentes principales (PCA). Se hicieron regresiones multivariadas de los puntajes de las poblaciones en los dos primeros ejes del PCA contra las variables ambientales de las localidades. Resultados: Las poblaciones desplegaron variación congruente con estrategias alternativas de asignación de biomasa. La estrategia conservativa mostró una alta biomasa de semilla y plántulas con tejidos densos y un mayor tejido radicular, mientras que el patrón opuesto caracterizó la estrategia adquisitiva. La evapotranspiración en mayo, la isotermalidad y el contenido de agua en el suelo en febrero fueron variables ambientales que predijeron los puntajes de las poblaciones en los dos primeros ejes del PCA. Conclusión: Los gradientes de disponibilidad de agua influyen en la masa de las semillas y la asignación de biomasa en P. laevigata.

RESUMO O estudo objetivou avaliar a distribuição espacial das defesas e das taxas de herbivoria em 20 espécies vegetais e a relação destas com o gradiente edáfico em quatro formações de restinga no Parque Estadual do Acaraí (PEA), Estado de Santa Catarina, Brasil. Atributos morfoanatômicos, histoquímicos e nutricionais foliares foram medidos em vinte folhas de dez indivíduos de cada espécie. Seis amostras de solo foram coletadas em cada formação para análise dos teores de macronutrientes, matéria orgânica, umidade e espessura da serapilheira. As análises estatísticas foram realizadas utilizando software R. Os resultados indicaram que as taxas de herbivoria variam de acordo com os atributos morfoanatômicos e histoquímicos foliares, os quais respondem às características nutricionais e hídricas do solo, influenciando o agrupamento de defesas anti-herbivoria em cada comunidade vegetal.

ABSTRACT This study aimed to evaluate the spatial distribution of defenses and herbivory rates in 20 plant species and their relationship with the edaphic gradient in four sandbank formations in the State Park of Acaraí (PEA) in Santa Catarina State, Brazil. The morphoanatomical, histochemical and nutritional attributes of the leaves were measured on twenty leaves of ten individuals of each species. Six soil samples were collected in each formation for analysis of macronutrient contents, organic matter, moisture and litter thickness. Statistical analyzes were performed with the R software. The results indicated that herbivory rates vary according to leaf morphoanatomical and histochemical attributes, which respond to the soil’s nutritional and water characteristics and, therefore, influence the anti-herbivory groups in each plant community.

Abstract Benthic cyanobacterial assemblages from ponds distributed along inland-coastal gradients in the McMurdo Sound region were studied during the 2011/12 Antarctic summer season. Twenty-five ponds were sampled in four distinct geographic locations, including the Lower and Upper Wright Valleys, Ross Island and the McMurdo Ice Shelf. For morphological identification, benthic mat samples were thawed and a subsample was directly observed by light microscopy. Remaining sample material was stored in 50 ml sterile polycarbonate bottles containing the mineral nutrient medium MLA for future studies, maintained at a temperature of 21°C. Ten morphological criteria were used to describe the morphotypes (trichome shape, number of trichomes in sheath, presence or absence of terminal attenuation of trichome, calyptra on mature apical cell, shape of apical cell, presence or absence of constrictions at transverse walls, granules, branching, range in width of trichomes and range of cell length) with reference to available identification literature. All morphospecies were documented using photomicrography. In total, 29 morphospecies were described, four assigned to the order Chroococcales, three to Nostocales and 22 to Oscillatoriales. The four geographic locations had similar taxonomic richness, sharing many morphospecies. However, each also contained distinct floristic elements that were rare or absent from the others.

Resumo O gradiente altitudinal entre outros fatores abióticos, está diretamente ligado à diversidade e distribuição de espécies. Outro fator importante é o posicionamento da cadeia de montanha, visto que as vertentes continental e oceânica possuem características distintas e podem exercer influência sobre a composição da vegetação. O objetivo deste estudo foi compreender a distribuição dos organismos pertencentes à família Passifloraceae sensu stricto em um gradiente de altitude, com variação de 300 a 2.199 m, no Parque Nacional Serra dos órgãos (PARNASO), localizado no estado do Rio de Janeiro, sudeste do Brasil. Foram realizadas expedições em campo para registro e coleta do material nas diferentes altitudes do PARNASO. Mapas de distribuição foram elaborados levando em consideração o esforço amostral, o gradiente de altitude e a pluviosidade. Foram realizadas análises estatísticas para estipular o padrão de riqueza e abundância dentro das classes de altitude. Para as vertentes oceânica e continental foram realizadas análises de similaridade, agrupamento e nMDS. Além disso, foram feitos cálculos de Área de Ocupação e Extensão de Ocorrência para avaliar o status de conservação das espécies. Foram registradas 19 espécies de Passifloraceae. As altitudes intermediárias apresentaram maior riqueza (1.100–1.300 m). A similaridade entre as vertentes foi de 28%, relatando riqueza distinta em ambos os lados da montanha. Os dados encontrados delimitam a distribuição e a composição de espécies de Passifloraceae dentro do PARNASO, tornando-se uma ferramenta colaborativa para ações de conservação do Parque.

Abstract Altitudinal gradients, among other abiotic factors, are directly linked to species’ diversity patterns and distributions. Another important factor to be considered is the geographic position of a mountain chain, with oceanic and continental-facing slopes having distinct environmental conditions reflected in distinct phytophysiognomies. We examined the distributions of species of Passifloraceae sensu stricto along an altitudinal gradient (varying from 300 to 2,199 m.a.s.l.) in the Serra dos Órgãos National Park (PARNASO) in Rio de Janeiro state, southeastern Brazil. Field excursions were undertaken to record and collect specimens. Maps were prepared of the distribution of sampling efforts, taking into consideration altitudinal gradients and rainfall. The statistical analysis was made to define the patterns of richness and abundance within the altitudinal classes. Analyses of similarity, grouping and NMDS were made of the oceanic and continental slopes. A total of 19 species of Passifloraceae s.s. were encountered. The greatest species richness was found at intermediate elevations (1,100–1,300 m.a.s.l). The similarity index between the two exposure slopes was 28%, indicating distinct species compositions on different faces. Our data helps to define the distribution and species composition of Passifloraceae s.s. within the PARNASO, and should be useful for conservation actions there.

Abstract In this study, we aimed to assess the spatial variability of microclimate inside a closed compost-bedded pack barn (CBP) with a negative ventilation system during summer and winter. The research was carried out in a CBP located in the Zona da Mata region, Minas Gerais, Brazil. For each of the stations analyzed, the following environmental mean variables observed inside a CBP were measured: air dry-bulb temperature (tdb), air relative humidity (RH), and windspeed, Temperature-Humidity index, and specific enthalpy. The kriging maps showed that the most critical housing conditions in the thermal environment were found, mainly, from the central part of the CBP, close to the exhaust fans. The analyses also pointed out that the system presented temperature gradients along the length, up to 3°C. During the summer afternoon, the entire region of the CBP was in a discomfort situation (tdb>26°C; RH>75%). During the winter, the measured environmental data remained within the comfort zone throughout the facility. However, probably due to the lack of thermal insulation of the material used to close the sides of the CBP, it did not allow spatial thermal uniformity for both seasons. It was also inefficient to keep the animals within the comfort zone for lactating cattle during the critical summer period.

Abstract Despite growing knowledge on the distribution and functioning of dryland vegetation types, their internal biodiversity structure (i.e., subregions) is much less studied. In the delineation of subregions, the use of species occurrence or abundance data may reveal different aspects of metacommunity structure. We revisit the issue of the bioregionalization of the woody flora of the Caatinga, the largest block of the dry forest and woodland biome in Latin America, using abundance data. We also evaluated the drivers of the spatial distribution of plant subregions: historical, current environmental and human effects. Using a K-means partition on interpolated NMDS axes, we identified 10 abundance subregions. Aridity, topography and soil, biome stability since the Pleistocene, and historical indigenous effects were retained by a Multinomial Logistic regression model, and their combined fractions explained most of the abundance variability in subregions. The subregions we present may support spatialized conservation and management decisions in the lack of detailed local data. The present results confirm the Caatinga woody flora broad composition patterns uncovered using presence-absence data in previous studies. Additionally, we found larger subregions than those identified with presence and absence data, suggesting the existence of oligarchies of dominant species in distinct parts of the Caatinga biome.

Resumo No norte da Tunísia, riachos sazonais chamados wadi são caracterizados por condições hidrológicas e térmicas extremas. Esses sistemas de água doce têm características muito particulares como resultado de sua forte irregularidade de fluxo devido ao regime de escoamento de precipitação limitado, levando a fortes flutuações hidrológicas sazonais. O estudo atual enfocou a distribuição espaço-temporal dos quironomídeos em 28 locais de amostragem espalhados pelo norte da Tunísia. Ao aplicar PERMANOVA, os resultados indicaram uma variação espaço-temporal significativa ao longo de vários gradientes ambientais. Os principais fatores abióticos responsáveis pelas diferenças observadas na distribuição espacial dos quironomídeos no wadi foram a condutividade e a temperatura, seguidos de perto por altitude, pH, salinidade, declive do talvegue e oxigênio dissolvido, identificados como tais empregando o procedimento de modelos lineares baseados na distância. A ordenação da análise de redundância baseada em distância mostrou dois grupos principais: o primeiro agrupou os sítios Bizerte, que foram caracterizados por alta condutividade da água, concentração de sódio e salinidade. O segundo grupo principal compreendia locais da zona de Tell e era caracterizado por baixas temperaturas, pH neutro, baixa condutividade e conteúdo de nutrientes. A subfamília Tanypodiinae (por exemplo, Prochladius sp., Prochladius choerus [Meigen, 1804] e Macropelopia sp.) era o grupo dominante na zona de Tell, enquanto espécies como Diamesa starmachi (Kownacki et Kownacha, 1970) e Potthastia gaedii (Meigen, 1838) foram encontradas apenas em Tell Wadis. Em contraste, espécies de quironomídeos, como Diamesa starmachi (Kownacki et Kownacha, 1970), Potthastia gaedii (Meigen, 1838), Procladius choreus (Meigen, 1804), eram específicas para Tell Mountain. A região de Cap Bon wadis foi dominada pelo gênero Cladotanytarsus sp. Os resultados desta pesquisa gostaram da composição taxonômica das assembleias de quironomídeos com a variação dos gradientes hidromorfológicos e físico-químicos nos wadis do norte da Tunísia.

Abstract In Northern Tunisia, seasonal streams, called wadi, are characterized by extreme hydrological and thermal conditions. These freshwater systems have very particular features as a result of their strong irregularity of flow due to limited precipitation runoff regime, leading to strong seasonal hydrologic fluctuations. The current study focused on the spatio-temporal distribution of chironomids in 28 sampling sites spread across the Northern Tunisia. By emplying PERMANOVA, the results indicated a significant spatio-temporal variation along various environmental gradients. The main abiotic factors responsible for noted differences in the spatial distribution of chironomids in wadi were the conductivity and temperature, closely followed by altitude, pH, salinity, talweg slope and dissolved oxygen, identified as such by employing distance-based linear models’ procedure. The Distance-based redundancy analysis ordination showed two main groups: the first clustered the Bizerte sites, which were characterized by high water conductivity, sodium concentration and salinity. The second main group comprised sites from the Tell zone and was characterized by low temperatures, neutral pH, low conductivity and nutrients content. The subfamily TANYPODIINAE (e.g., Prochladius sp., Prochladius choerus (Meigen, 1804) and Macropelopia sp.) was the dominant group at Tell zone, whereas species such as Diamesa starmachi (Kownacki et Kownacha, 1970) and Potthastia gaedii (Meigen, 1838) were found only in Tell Wadis. In contrast, chironomid species such as Diamesa starmachi (Kownacki et Kownacha, 1970), Potthastia gaedii (Meigen, 1838), Procladius choreus (Meigen, 1804) were specific for Tell Mountain. Cap Bon wadis region was dominated by genus Cladotanytarsus sp. The results of this survey liked the taxonomic composition of chironomid assemblages to the variation of hydromorphological and physic-chemical gradients across the northern Tunisia wadis.

Meiobenthos (or meiofauna) are microscopic invertebrates that inhabit biofilms and interstitial spaces in rivers. They are diverse and extremely abundant, and they perform essential ecological functions by linking microbial production to higher trophic levels (e.g. macrobenthic invertebrates and fishes). However, meiobenthic communities remain poorly studied in Africa. Here, we sampled meio- and macrobenthic invertebrate communities associated with biofilms and sediments across an upstream-downstream gradient along the Olifants, Sabie and Crocodile rivers flowing through the Kruger National Park (KNP). We expected to link differences in community structure to environmental gradients as those rivers show different degrees of anthropogenic stress as they enter the park. Both meio- and macrobenthic communities differed across rivers and also structured along an upstream-downstream gradient. The upstream sites, which were the closest to the park borders, consistently showed a lower diversity in all three rivers. There, the invasive snail Tarebia granifera strongly dominated (making up 73% - 87% of the macrobenthos), crowding hard substrates, while concomitantly the abundances of biofilm-dwelling meiobenthos like nematodes and rotifers were substantially reduced. Nevertheless, the diversity and evenness of communities then tended to increase as water flowed downstream through the park, suggesting a beneficial effect of protected river reaches on benthic invertebrate diversity. However, for the Crocodile River, which makes up the southern border of the park, this trend was less conspicuous, suggesting that this river may experience the greatest threats. More generally, benthic invertebrate communities were driven by the concentrations of phosphates, sulphates, ammonium and organic matter and by substrate characteristics. CONSERVATION IMPLICATIONS: Meiobenthic organisms are very abundant in KNP rivers and react to environmental gradients; thus, they should be more considered for bio-monitoring or conservation of comprehensive assemblages of animals. Interestingly, protected reaches tended to show a reduced dominance of the invasive T. granifera and a higher diversity of benthic invertebrates