Resumen Comprender la estructura y diversidad forestal permite elaborar y analizar estrategias para el manejo sustentable de los recursos naturales. El objetivo de la investigación fue contribuir al conocimiento de la estructura arbórea, así como su capacidad de regeneración en un gradiente altitudinal en un Área Natural Protegida, en Madera, Chihuahua. El estudio comprendió tres intervalos altitudinales: inferior (2 307 a 2 466 m), medio (2 466 a 2 625 m) y superior (2 625 - 2 785 m), en los que se distribuyeron 30 sitios circulares de 500 m2 donde se midió el diámetro y altura del arbolado superior, así como la densidad de la regeneración. La estructura vertical se obtuvo con el índice de Pretzsch (A), además, se evaluó el índice de valor de importancia (IVI), la diversidad con el índice de Shannon-Wiener (H’) y riqueza con Margalef (D mg ), asimismo, se estimó la capacidad de renuevo y los daños presentes. Los valores de A muestran la mayor homogeneidad estructural en el intervalo 2; la familia Pinaceae registró el peso ecológico superior en el IVI; los valores de H’ y D mg fueron superiores en el estrato II, sin embargo, todos se consideran de baja diversidad y riqueza; las especies Abies concolor y Pseudotsuga menziesii, mostraron la mayor proporción de regeneración en la comunidad, en la que la supresión es el daño frecuente, no obstante, el 95% de los individuos no presentaron afectaciones. Esta información es de utilidad para la conservación de estas comunidades de importancia ecológica en bosques templados.

Abstract Understanding forest structure and diversity allows the development and analysis of strategies for the sustainable management of natural resources. The objective of the research was to contribute to the knowledge of tree structure, as well as its regeneration capacity in an altitudinal gradient in a Natural Protected Area in Madera, Chihuahua. The study included three altitudinal intervals: lower (2 307 to 2 466 m), middle (2 466 to 2 625 m) and upper (2 625 - 2 785 m), in which 30 circular sites of 500 m2 were distributed where the diameter and height of the upper trees were measured, as well as the density of regeneration. The vertical structure was obtained with the Pretzsch index (A), in addition, the importance value index (IVI), diversity with the Shannon-Wiener index (H') and richness with Margalef (D mg ) were evaluated, as well as the renewal capacity and damage present. The values of A show the greatest structural homogeneity in interval 2; the Pinaceae family registered the highest ecological weight in the IVI; the values of H' and Dmg were higher in stratum II, however, all are considered of low diversity and richness; the species Abies concolor and Pseudotsuga menziesii, showed the highest proportion of regeneration in the community, in which suppression is the frequent damage, however, 95% of the individuals were not affected. This information is useful for the conservation of these ecologically important communities in temperate forests.

ABSTRACT Edge effects are changes in vegetation, microclimate conditions and soil in transition bands between the edge and interior of the forest. The objective of this study was to verify for how many meters it is possible to perceive structural floristic variations caused by the Edge Effect by analyzing the tree and regenerative strata of four seasonal semi-deciduous forests located in the Cerrado Biome, Brazil. Samples were taken from four fragments of semi-deciduous forests in the Cerrado and analyzed by dendrograms and regressions for structural parameters that could distinguish edge and interior regions. In the Bray-Curtis Index and in the Sørensen Coefficient, for the tree stratum, the fragments presented groups with plots close to 40 meters from the edge. For the regenerative stratum the groups were more difficult to distinguish, even with a tendency to floristic dissimilarity of 15 to 20 meters. The groups were statistically confirmed by the Similarity Analysis (ANOSIM). The similarity percentage (SIMPER) can relate the species according to their contribution to the division into groups and to the areas of greatest interest. In the analysis of the structural data, the relationships between the number of trees, species and basal area as a function of the edge were not proven. Similarity analyzes distinguished the interior from the edge and measured the distance covered in the studied fragments, demonstrating that the composition of the first 40 meters of forest can be considered edges. vegetation semideciduous semi deciduous Biome Brazil regions BrayCurtis Bray Curtis Coefficient 4 1 2 ANOSIM. ANOSIM . (ANOSIM) SIMPER (SIMPER interest data trees proven edges (ANOSIM

RESUMO Os Efeitos de Borda são modificações na vegetação, nas condições microclimáticas e no solo na transição entre o meio exterior e o interior da floresta. O objetivo deste estudo foi verificar até quantos metros é perceptível variações florístico estruturais ocasionadas pelo Efeito de Borda, analisando-se o estrato arbóreo e regenerativo de quatro fragmentos de Floresta Estacional Semidecidual localizados no bioma Cerrado. A partir da amostragem realizada nestes quatro fragmentos, foram analisadas, por meio de dendrogramas e regressões, se os parâmetros estruturais podem distinguir regiões de borda e de interior. Para o estrato arbóreo, nos dendrogramas de similaridade (Bray-Curtis e Sørensen), os fragmentos apresentaram grupos com parcelas semelhantes até os 40 metros de borda. Para o estrato regenerativo, os grupos foram mais difíceis em distinguir, mesmo com tendência, a dissimilaridade florística de 15 a 20 m. A partir da Análise de Similaridade (ANOSIM), os grupos foram confirmados estatisticamente. A porcentagem de similaridade (SIMPER) pode relacionar as espécies em função da sua contribuição para a divisão dos grupos e para as áreas de maior interesse. Nas análises dos dados estruturais, não foram comprovadas as relações do n° de árvores, espécies e área basal em função da borda. As análises de similaridade foram capazes de distinguir o interior da borda e mensurar a distância percorrida nos fragmentos estudados, demonstrando que a composição dos primeiros 40 m de floresta pode ser considerada borda. vegetação analisandose analisando Cerrado analisadas regressões BrayCurtis Bray Curtis Sørensen, Sørensen , Sørensen) 4 tendência 1 2 ANOSIM, ANOSIM (ANOSIM) estatisticamente SIMPER (SIMPER interesse n árvores estudados (ANOSIM

Abstract Assessing diversity allows us to know the general state of ecological systems, the impact of climate change, forest management and other anthropic activities, and has been used for practical purposes of conservation, monitoring and management of forests. The objective of the study was to analyze the structure, diversity and similarity of the tree stratum of Pseudotsuga menziesii forests in Mexico, a species listed in NOM-059-SEMARNAT-2010, whose areas are considered of High Conservation Value. The present study included 11 of the 14 states where this species is distributed in Mexico. Information from 28 Pseudotsuga communities was analyzed and processed, obtained from the National Forest and Soil Inventory, research works and own information; horizontal structure was determined with the Importance Value Index (IVI), diversity with the Shannon-Wiener (H') and Pielou (J) index, significant differences in diversity were determined with the Hutcheson's t-test, and floristic similarity was obtained with the Morisita-Horn index. At the national level, 9 families, 14 genera and 45 species were recorded, the IVI of Pseudotsuga fluctuates between 20.77 and 53.33; H' values generally indicate low diversity (<2.00) and high J-equity (>0.70). The Morisita index presents three groupings corresponding to the physiographic provinces Sierra Madre Occidental, Sierra Madre Oriental and Faja Volcánica Transmexicana, and reflects a high similarity within each province and medium to low similarity between regions. This work will contribute to the development of management strategies for monitoring and conservation in these forests.

Resumen Evaluar la diversidad permite conocer el estado general de los sistemas ecológicos, el impacto del cambio climático, del manejo forestal y otras actividades antrópicas, se ha utilizado con fines prácticos de conservación, monitoreo y gestión de los bosques. El objetivo del estudio fue analizar la estructura, diversidad y similitud del estrato arbóreo de los bosques de Pseudotsuga menziesii en México, especie enlistada en la NOM-059-SEMARNAT-2010, cuyas áreas son consideradas de Alto Valor de Conservación. El presente estudio comprendió 11 de los 14 estados donde se distribuye esta especie en México. Se analizó y procesó información de 28 comunidades de Pseudotsuga, obtenidas del Inventario Nacional Forestal y de Suelos, trabajos de investigación e información propia; la estructura horizontal se determinó con el Índice de Valor de Importancia (IVI), la diversidad con el índice de Shannon-Wiener (H’) y Pielou (J), se determinaron las diferencias significativas en diversidad de H’ con la prueba de t de Hutcheson, y la similitud florística se obtuvo con el índice de Morisita-Horn. A nivel nacional se registraron 9 familias, 14 géneros y 45 especies, el IVI de Pseudotsuga fluctúa entre 20.77 a 53.33; los valores de H’ en general indican baja diversidad (<2.00) y alta equidad J (>0.70). El índice de Morisita presenta tres agrupaciones correspondientes a las provincias fisiográficas Sierra Madre Occidental, Sierra Madre Oriental y Faja Volcánica Transmexicana, y refleja una alta semejanza dentro de cada provincia y media a baja entre regiones. El presente trabajo coadyuvará al desarrollo de estrategias de manejo en estos bosques para su monitoreo y conservación.

Abstract In the savanna-seasonally dry tropical forest ecotone in Northeastern Brazil, we studied variations in flora and structure within old growth and two sites in secondary succession (10 and 25 years). We sampled 2,127 trees and shrubs with a diameter at ground level of 3 cm or more, excluding cacti, palm trees, and vines. Old growth contained 478 plants from 29 species, the 25-year site had 819 plants from 27 species, and the 10-year site had 829 plants from 25 species, totaling 38 species across the sites. Regarding the regenerating stratum, we found 2,776 individuals, with the largest and smallest number of individuals for 10 and 25 years regeneration, respectively. Rarefaction and Jacknife richness showed greater tree richness in old growth, whereas 10 and 25 years regeneration presented similar richness estimates; furthermore, the highest richness in the regenerating stratum was observed in 10 years and the lowest in old growth. Our results reveal that changes in composition are caused by species replacement, demonstrating that even in areas deforested for traditional agriculture, turnover causes significant changes in composition and results in the requirement of a long time for reestablishment, similar to the old growth. savannaseasonally savanna seasonally Brazil (1 2 years. . years) 2127 127 2,12 more cacti vines 47 25year year 81 10year 82 2776 776 2,77 1 respectively estimates furthermore replacement agriculture reestablishment ( 212 12 2,1 4 8 277 77 2,7 21 2, 7

Resumo Em uma área de ecótono entre a savana e a floresta tropical sazonalmente seca no Nordeste do Brasil, estudamos variações na flora e na estrutura em áreas com estágio de sucessão avançada e em dois locais em sucessão secundária (10 e 25 anos). Amostramos 2.127 árvores e arbustos com um diâmetro ao nível do solo de 3 cm ou mais, excluindo cactos, palmeiras e trepadeiras. A vegetação antiga continha 478 plantas de 29 espécies, o local de 25 anos tinha 819 plantas de 27 espécies, e o local de 10 anos tinha 829 plantas de 25 espécies, totalizando 38 espécies nos locais. Em relação ao estrato regenerante, encontramos 2.776 indivíduos, com maior e menor número de indivíduos para 10 e 25 anos de regeneração, respectivamente. Rarefação e riqueza de Jacknife mostraram maior riqueza de árvores em crescimento antigo, enquanto 10 e 25 anos de sucessão secundária apresentaram estimativas de riqueza semelhantes; além disso, a maior riqueza no estrato regenerante foi observada em 10 anos de sucessão secundária e a menor em crescimento antigo. Nossos resultados revelam que as mudanças na composição são causadas pela substituição de espécies, demonstrando que mesmo em áreas desmatadas para agricultura tradicional, o turnover causa mudanças significativas na composição e resulta na exigência de um longo tempo para restabelecimento, semelhante ao crescimento antigo. Brasil (1 2 anos. . anos) 2127 127 2.12 mais cactos trepadeiras 47 81 1 82 2776 776 2.77 regeneração respectivamente antigo semelhantes disso tradicional restabelecimento ( 212 12 2.1 4 8 277 77 2.7 21 2. 7

Abstract The objective of this study was to characterize a Pinus-Quercus forest through ecological indicators and the composition of species present in the tree stratum in Huiztlatzala, Guerrero. Twenty-five circular sites of 500 m2 were established to inventory the adult trees and their dasometric variables (total height, normal diameter greater than 5 cm and cover). The structural parameters of the forest (density, dominance, basal area and cover) were used to calculate the Importance Value index and the similarity indexes.) Species richness was estimated with the Chao 1 and Bootstrap models. The Jaccard index was used to determine similarity between sites. The results showed seven species distributed in two genera and two families Pinus teocote recorded a mean height of 9.51 m and a diameter of 19.55 cm higher than other species, with an importance value of 148% in contrast to Quercus rubramenta 57%. Richness estimators indicated that more than 98% of the calculated species per 1 ha were recorded for each site (H'= 1.27, λ= 0.68). The results obtained allowed us to identify the dimensions, structural parameters and species dominance; of these, Pinus teocote had the highest value. It is concluded that the community has a low diversity and richness of tree species, due to the change in land use by human influence. It is necessary to establish restoration and conservation activities to avoid forest deterioration.

Resumen El objetivo del presente estudio fue caracterizar un bosque de Pinus-Quercus a través de indicadores ecológicos y la composición de especies presentes en el estrato arbóreo en Huiztlatzala, Guerrero. Se establecieron 25 sitios circulares de 500 m2 para hacer el inventario del arbolado adulto y sus variables dasométricas (altura total, diámetro normal mayor a 5 cm y cobertura). Los parámetros estructurales del bosque (densidad, dominancia, área basal y cobertura) se emplearon para calcular el índice de Valor de Importancia, y los índices de similitud). La riqueza de especies forestales se estimó con los modelos Chao 1 y Bootstrap. El índice de Jaccard se utilizó para determinar la similitud entre sitios. Los resultados mostraron siete especies forestales distribuidas en dos géneros, y dos familias Pinus teocote registraron una altura media de 9.51m y un diámetro de 19.55 cm superior al de otras especies, con un valor de importancia de con un 148% contraste con Quercus rubramenta 57%. Los estimadores de riqueza indicaron que se registró más del 98% de las especies calculadas por 1 ha para cada sitio (H'= 1,27, λ= 0,68). Los resultados obtenidos permitieron identificar las dimensiones, parámetros estructurales y dominancia de las especies; de ellas, Pinus teocote fue la de mayor valor. Se concluye que la comunidad presenta una baja diversidad y riqueza de especies arbóreas, debido al cambio de uso del suelo por influencia humana. Es necesario establecer actividades de restauración y conservación para evitar el deterioro del bosque.

Resumen Los bosques secos tropicales albergan una alta diversidad y endemismos de flora y fauna, sin embargo, se encuentran entre los ecosistemas más amenazados del mundo. En este estudio se analizó la composición, estructura, diversidad y usos tradicionales de las plantas en la localidad de San Gabriel Casa Blanca, dentro de la Reserva de la Biosfera Tehuacán-Cuicatlán, en Oaxaca, México. La vegetación en el paisaje de estudio es representativa de las zonas semiáridas, compuesta por bosque seco tropical, matorral y zonas de agricultura. Durante la época de lluvias del 2018 se establecieron 30 sitios de muestreo en cinco unidades del paisaje. Se muestreó el estrato arbóreo y el arbustivo y se evaluaron la diversidad, la composición y la estructura de la vegetación. Además, se llevaron a cabo encuestas y talleres para conocer las especies utilizadas por la población. Se identificaron un total de 71 especies pertenecientes a 24 familias botánicas. Las familias con mayor representación fueron Cactaceae, Euphorbiaceae y Leguminosae; mientras que las especies fueron Neobuxbaumia tetetzo, Bursera fagaroides, Opuntia pilifera, Myrtillocactus geometrizans y Amphipterygium adstringens. La composición de especies varió entre las diferentes unidades del paisaje, siendo la unidad con presencia agrícola la que tuvo menor diversidad de especies. Con base en talleres y entrevistas, se determinaron un total de 54 especies de plantas con usos tradicionales en la localidad. Los resultados sugieren que bajo un esquema de manejo y planes de conservación adecuados como los que se practican en este sitio, se puede mantener la composición y diversidad vegetal representativa de esta reserva.

Abstract Tropical dry forests maintain a high diversity and endemic flora and fauna but are among the most threatened ecosystems in the world. In the present study we analyzed the composition, structure, diversity, and traditional uses of the plants in the locality of San Gabriel Casa Blanca, within the Tehuacán-Cuicatlán Biosphere Reserve, Oaxaca, Mexico. The vegetation in the study landscape is representative of the semi-arid areas composed by tropical dry forest, scrub, and agricultural areas. During the rainy season of 2018, 30 sampling sites were sampled in five landscape units. The tree and shrub stratum were sampled and vegetation diversity, composition and structure were evaluated. Additionally, surveys and workshops were conducted to understand the plant species utilized by the population. A total of 71 species belonging to 24 botanical families were identified. The best represented families were Cactaceae, Euphorbiaceae and Leguminosae; while the species were Neobuxbaumia tetetzo, Bursera fagaroides, Opuntia pilifera, Myrtillocactus geometrizans and Amphipterygium adstringens. The composition of species varied among the different landscape units, being the unit with agricultural presence the one that had the least diversity of species. Based on interviews, a total of 54 species of plants with traditional uses in the locality were determined. The results of the present study suggest that under an adequate management scheme and conservation plans such as those practiced in this site, the representative composition and plant diversity of this reserve can be maintained.

Abstract Background: There is limited information to predict the direction in which canopy modification affects the microbial carbon use efficiency (CUE) and, consequently, the magnitude and stability of litter decomposition in monodominant sacred fir (Abies religiosa) forests. Questions: What is the effect of tree stratum alteration on CUE and stability of litter decomposition in an A. religiosa forest? Study sites and dates: Two conditions inside a sacred fir forest were selected: A) a naturally monodominant homogeneous condition, and B) a heterogeneous condition with a non-monospecific tree stratum derived from local disturbances (wildfire and reforestation) occurred on a single occasion 18 years ago. Methods: In each condition (homogeneous and heterogeneous), the Importance Value Index (IVI) was calculated in the tree stratum, while chemical composition, microbial carbon (C) concentration, enzyme activities and C mineralization were measured in litter samples. The specific enzymatic activity and the metabolic quotient were calculated as CUE indicators, and the coefficient of variation as a proxy for litter decomposition stability. Results: A change in tree species composition and an increase in tree species richness in the heterogeneous condition was found, which decreased litter phosphorous (P) concentration. This promoted a high microbial activity and low CUE, favoring C mineralization. Furthermore, low stability during litter decomposition was observed as tree species richness increased. Conclusions: Tree stratum heterogeneity, as a consequence of past disturbances, decreases CUE and the stability of litter decomposition in an A. religiosa forest.

Resumen Antecedentes: Existe poca información para prever la dirección en la cual la modificación del dosel afecta el uso eficiente del carbono (UEC) por la comunidad microbiana y, consecuentemente, la magnitud y estabilidad de la descomposición del mantillo en bosques monodominantes de Abies religiosa. Preguntas: ¿Cuál es el efecto de una alteración del estrato arbóreo sobre el UEC y la estabilidad de la descomposición del mantillo en un bosque de A. religiosa? Sitios y años de estudio: Se seleccionaron dos condiciones: A) monodominante homogénea y B) heterogénea con un estrato arbóreo polidominante derivado de disturbios localizados (incendio y reforestación) ocurridos en una sola ocasión hace 18 años. Métodos: En cada condición, se obtuvo el Índice de Valor de Importancia en el estrato arbóreo, y la composición química, concentración de carbono (C) microbiano, actividades enzimáticas y mineralización de C del mantillo. Se calculó la actividad enzimática específica y el coeficiente metabólico como indicadores del UEC, y el coeficiente de variación como indicador de estabilidad de la descomposición. Resultados: El cambio en la composición y riqueza arbórea redujo la concentración de fósforo (P) del mantillo en la condición heterogénea. Esto aumentó la actividad microbiana y redujo el UEC, incrementando la mineralización de C. Además, existió una baja estabilidad durante la descomposición del mantillo conforme incrementó la riqueza arbórea. Conclusiones: La heterogeneidad del estrato arbóreo, como consecuencia de disturbios pasados, reduce el UEC y la estabilidad de la descomposición del mantillo en un bosque de A. religiosa.

Resumen Los bosques de Pinus-Quercus constituyen ecosistemas de gran importancia ecológica. La estructura y composición son indicadores de la biodiversidad en estas asociaciones forestales, en las cuales esos dos elementos son clave para su estabilidad y conservación. El objetivo del presente estudio fue caracterizar un bosque de Pinus-Quercus a través de los parámetros estructurales y de la composición de especies presentes en el estrato arbóreo en el municipio El Porvenir, Chiapas. Se establecieron seis sitios circulares de muestreo, con una superficie de 400 m2 para evaluar el arbolado adulto y sus variables dasométricas (altura total, diámetro normal y cobertura). Los parámetros estructurales del bosque (densidad, dominancia, área basal y cobertura) se emplearon para calcular los índices de Valor de Importancia, valor forestal, complejidad de Holdrige y los índices de similitud. Los resultados mostraron la presencia de seis especies; Pinus maximinoi registró una altura media de 18.88±6.72 m (p<0.0001, F=5.46) superior a los otros taxones. Además, le correspondió el mayor diámetro normal (30.58±13.64 cm, p<0.0002, F=5.18), Valor de Importancia (161.07 %) y valor forestal (108.08 %). El índice de complejidad de Holdrige del bosque fue de 45.22 %. Los resultados obtenidos permitieron identificar las dimensiones, parámetros estructurales y dominancia de las especies; de ellas, Pinus maximinoi fue la de mayor valor.

Abstract Pinus-Quercus forests are ecosystems of great ecological importance. Structure and composition are indicators of biodiversity in these forest associations, being two key elements for their stability and conservation. The objective of this study was to characterize a Pinus-Quercus forest based con the structural parameters and species composition present in the arboreal stratum in the municipality of El Porvenir, Chiapas. Six 400 m2 circular sites were established to evaluate the adult trees and their dasometric variables (total height, normal diameter and cover). The structural parameters of the forest (density, dominance, basal area and cover) were used to calculate the indexes of Importance Value, forest value, Holdrige complexity index and similarity index. The results showed the presence of six species; Pinus maximinoi exhibited a mean height of 18.88±6.72 m (p<0.0001, F= 5.46), which is greater than that of other species. In addition, it has the highest normal diameter (30.58±13.64 cm, p<0.0002, F=5.18), Importance Value (161.07 %) and forest value (108.08 %). The Holdrige complexity index of the forest is 45.22 %. The results obtained made it possible to identify the dimensions, structural parameters, and dominance of the species, with Pinus maximinoi being the most valuable.

Abstract An analysis was carried out to assess the effect, over a period of 10 years, of the application of the forestry selection method on diversity and structure in a temperate forest of the mountain range of the state of Durango, Mexico. Twelve Permanent Forest and Soil Research Sites (PFS and SRS) were compared and remeasured. The comparative analysis was performed using the Shannon-Wiener diversity index; the Importance Value index ―estimated by density, basal area, and species frequency at the sampling sites―, and three structure indexes for determining the species mixture, spatial distribution, and dominance of woodland. The Shannon-Wiener index did not exhibit significant statistical changes between the assessment periods when the Hutcheson t test was applied; the analysis showed that relative percentage values of abundance, dominance, and frequency, and the significance value index remained the same; structure indexes were not significantly modified in the 10-year interval after forest extraction; therefore, it was concluded that the forestry treatment applied does not modify the diversity or structure components of the tree stratum.

Resumen Se realizó un análisis para evaluar el efecto, en un periodo de 10 años, de la aplicación del Método Silvícola de Selección sobre la diversidad y estructura en un bosque templado de la Sierra de Durango, México. Se compararon doce Sitios Permanentes de Investigación Forestal y de Suelos (SPIFyS), los cuales fueron remedidos. El análisis comparativo se hizo mediante el índice de Diversidad de Shannon-Wiener; asimismo, se estimó el Índice de Valor de Importancia (IVI) mediante la densidad, el área basal y la frecuencia de las especies en los sitios de muestreo; también se calcularon tres índices de estructura para conocer la mezcla de especies, distribución espacial y dominancia del arbolado. El índice de Shannon-Wiener no evidenció cambios estadísticos significativos entre periodos de evaluación, cuando se aplicó la prueba de t de Hutcheson; el análisis mostró que los valores porcentuales relativos de abundancia, dominancia, frecuencia e Índice de Valor de Importancia se conservan. Los índices de estructura tampoco se modificaron significativamente en el intervalo de 10 años después de la extracción forestal, por lo que se determina que el tratamiento silvícola aplicado no modifica la diversidad ni los componentes de estructura del estrato arbóreo.

Abstract The structure and tree diversity of oak forests in two micro-watersheds in central Mexico were characterized. The diameters (≥ 5 cm) and heights of the trees in circular plots of 1000 m2 were measured. The horizontal structure was analyzed based on the value of relative importance (VIR); the diameters of six species shared at both sites were compared with the Mann-Whitney test, and the Pretzsch A index was used for the vertical structure. For alpha and beta diversity, PAS 4.3 software was used. In both cases Quercus laurina and Quercus rugosa obtained the highest values of density, dominance, and VIR; although there are no differences between the diameters, young specimens predominate (diameters 5 - 23 cm) and present a typical distribution of an inverted J, frequent in naturally regenerating forests. However, Quercus crassipes shows a decrease in individuals (< 15 cm), which suggests possible displacement. The vertical distribution indicates that the height is distributed mainly in stratum III (< 15 m). In terms of diversity, the difference is not significant, although the specific richness was 22 and 12 species in CPG and CRP, respectively, and there was? an intermediate replacement. The results of this work contribute to understanding the ecological processes of structure, diversity, and interaction between tree populations in these communities, so it is necessary to monitor especially species with behaviors such as Q. crassipes.

Resumen Se caracterizó la estructura y diversidad arbórea de bosques de encino en dos microcuencas del centro de México. Se midieron los diámetros (≥ 5 cm) y alturas de los árboles en parcelas circulares de 1000 m2. La estructura horizontal se analizó con base en el valor de importancia relativa (VIR); se compararon los diámetros de seis especies que comparten ambos sitios con la prueba Mann-Whitney y para la estructura vertical se empleó el índice A de Pretzsch., mientras que para la diversidad alfa y beta se utilizó el software PAS 4.3. En ambos casos Quercus laurina y Quercus rugosa obtuvieron los valores más altos de densidad, dominancia y de VIR, aunque no existen diferencias entre los diámetros, predominan los ejemplares jóvenes (diámetros 5 cm - 23 cm) y presentan una distribución típica de J invertida, frecuente en bosques con regeneración natural. Sin embargo, Quercus crassipes muestra un descenso en individuos (< 15 cm), lo que sugiere un posible desplazamiento. La distribución vertical indica que la altura se distribuye principalmente en el estrato III (< 15 m). En cuanto a diversidad arbórea la diferencia no es significativa, aunque la riqueza específica fue de 22 y 12 especies en CPG y CRP, respectivamente, y hubo un recambio intermedio. Los resultados de este trabajo contribuyen a entender los procesos ecológicos de estructura, diversidad e interacción entre poblaciones de árboles de estas comunidades por lo que es necesario dar seguimiento sobre todo a especies con comportamientos como Q. crassipes.

Resumen Introducción: A pesar del interés que despiertan los ecosistemas derivados de las formaciones guyanesas, se desconoce la estructura vertical de las comunidades y las relaciones de la biota con las condiciones climáticas. Objetivo: Caracterizar la estructura y composición vertical de la artropofauna asociada a tres de los ecosistemas más representativos de la zona norte de la serranía de La Lindosa en Colombia, con base en parámetros morfológicos y ecológicos. Métodos: Se muestreó la artropofauna, desde el nivel del suelo subsuperficial hasta los estratos arbustivos y arbóreos, y se identificó hasta el nivel de familia o grupo supraespecífico. Se determinaron los valores de diversidad Alfa y Beta, se realizaron mediciones de la longitud corporal y se determinó la coloración y el nivel trófico de cada grupo. Resultados: La composición y diversidad de la artropofauna fue diferente en cada ecosistema y estrato vertical y la mayoría de los grupos de artrópodos en todos los ecosistemas estudiados presentan abundancias bajas. Los grupos de hábitos fitófagos y depredadores fueron frecuentes en todos los ecosistemas y la mayor biomasa de artropofauna proviene de grupos de hábitos polífagos, de tamaño medio y de gran abundancia. Las coloraciones claras y oscuras son las más frecuentes a escala de paisaje. Conclusión: Los ecosistemas estudiados se caracterizan por los bajos valores de diversidad y recambio y por la gran cantidad de grupos no compartidos que aparentemente responden a las características microclimáticas; sin embargo, existen algunas generalidades a escala de paisaje como la mayor riqueza y abundancia de grupos en los estratos intermedios, la mayor proporción de grupos de hábitos fitófagos y tallas corporales medianas y el predominio de coloraciones oscuras en los estratos inferiores.

Abstract Introduction: Despite growing interest by the ecosystems derived from the Guyanese formations, the vertical structure of the communities and relationships of the biota with the climatic conditions in these ecosystems are unknown. Objective: Characterize the structure and vertical composition of the arthropod fauna associated with three of the most representative ecosystems of the Northern area of the serranía de La Lindosa in Colombia based on morphological and ecological parameters. Methods: The arthropod fauna was sampled, from the subsurface soil level to the shrub and tree stratum. The fauna was determined up to the level of family or supraspecific group and the values of Alfa and Beta diversity were determined. Body length measurements were made, and the coloration and trophic level of each group were determined. Results: The composition and diversity of the arthropod fauna was different in each ecosystem and vertical stratum and most of the groups in all the ecosystems studied present low abundances. Groups of phytophagous and predatory habits were frequent in all ecosystems and the highest biomass of arthropod fauna comes from groups of polyphagous habits, of medium size and great abundance. Light and dark colorations are the most frequent in landscape-scale. Conclusion: The ecosystems studied are characterized by the low values of diversity and replacement and the large number of non-shared groups that apparently respond to the microclimatic characteristics; however, there are some generalities on a landsc ape scale such as the greater richness and abundance of groups in the intermediate strata, the greater proportion of groups with phytophagous habits and medium body sizes, and the predominance of dark colorations in the lower strata.

Resumo O objetivo do estudo foi avaliar a composição florística e estrutural em um trecho de floresta secundária, no município de Dona Francisca - RS. Foram instaladas 50 parcelas permanentes de dimensão 10 x 20 m, de modo sistemático, distanciadas 10 m entre si e 40 m entre faixas, totalizando 1 ha. Foram amostrados todos os indivíduos que apresentassem CAP ≥ 15,7 cm e calculado os estimadores fitossociológicos. Foi realizada a curva de acumulação de espécie para verificar a suficiência amostral. Para o cálculo de diversidade e dominância, utilizou-se o Índice de Shannon (H’) e Equabilidade de Pielou (J’). Para a riqueza potencial utilizaram-se os estimadores não paramétricos Jackknife. Avaliou-se a composição florística e estrutural por meio da Análise de Correspondência Distendida (DCA). Verificou-se, também, a distribuição diamétrica e hipsométrica da comunidade arbórea, e para as espécies, com valor de importância acima de 5 %, a distribuição em classes de DAP. As análises estatísticas foram realizadas no programa R. Foram identificadas 65 espécies arbóreas e arbustivas com 2.045 indivíduos distribuídas em 31 famílias botânicas. As espécies com valor de importância acima de 5% foram Casearia sylvestris (14,04%), Nectandra lanceolata (12,86 %), Cupania vernalis (9,57 %), Guarea macrophylla (7,29 %) e Ocotea puberula (5,07 %). Os valores para a diversidade e dominância foram, respectivamente, de 2,91 nats.ind-1 e 0,69, indicando que a área possui baixa diversidade e dominância de poucas espécies. Pela DCA é possível verificar que as parcelas estão distribuídas homogeneamente no trecho florestal. A distribuição diamétrica representou o esperado para a comunidade arbórea com tendência ao J-invertido e a maioria das árvores apresentou altura concentrada no estrato intermediário da floresta. Das cinco espécies analisadas, apenas Nectandra lanceolata e Ocotea puberula não apresentaram curva exponencial negativa. Foi possível observar que há um predomínio de indivíduos nas primeiras classes de DAP e altura, o que caracteriza a resiliência da área após distúrbio. Ainda, indica as flutuações e estabilidade das espécies, na sucessão ecológica, de uma floresta em estágio intermediário de regeneração.

Abstract The objective of the study was to evaluate the floristic and structural composition of an area located in a section of secondary Forest, in the municipality of Dona Francisca, RS state. To do so, 50 permanent plots with a dimension of 10 x 20 m (200 m2) were installed in a systematic way, 10 m apart and 40 m between tracks, totaling 1 ha. All individuals with CAP ≥ 15.7 cm were identified and sampled and the phytosociological estimators were calculated. The species accumulation curve was used to verify the sample adequacy. For the calculation of diversity and dominance estimators, the Shannon Index (H ‘) and Pielou Equability (J’) were used. Subsequently, the floristic and structural composition was evaluated through the Distributed Correspondence Analysis (DCA). It was also verified the diameter and histopic distribution of the tree community, and for the species, with importance value above 5%, the distribution in classes of DAP. Statistical analyzes were performed in the R program. 65 tree and shrub species were identified with 2,045 individuals distributed in 31 botanical families. The species with a value of importance above 5% were Casearia sylvestris (14, 04 %), Nectandra lanceolata (12, 86 %), Cupania vernalis (9, 57 %), Guarea macrophylla (7,29 %) and Ocotea puberula (5.07 %). The values for diversity and dominance were, respectively, 2.91 nats.ind-1 and 0.69, indicating that the area has low diversity and dominance of few species and that by DCA it is possible to verify that the plots are homogeneously distributed in the forest. The diameter distribution represented the expected behavior for the arboreal community with J-inverted tendency and the majority of the trees presented height concentrated in the middle stratum of the forest. Only Nectandra lanceolata and Ocotea puberula did not present negative exponential curve from the five species analyzed. It was possible to observe the mosaic of tree species distributed in the forest section. In addition, there is a predominance of individuals in the first classes of DBH and height, which characterizes the resilience of the area after the disturbance and its capacity for natural recovery. It also indicates the fluctuations and stability of species in ecological succession of a forest in an intermediate stage of regeneration.

Resumo No Sul do Brasil, parte dos remanescentes florestais é utilizada, historicamente, como sistemas silvipastoris denominados caívas, em Santa Catarina, e faxinais no estado do Paraná. Nestes, o estrato herbáceo da floresta é composto por pastagem naturalizada onde ocorre o pastejo animal. Visando contribuir para o melhor entendimento do impacto das caívas sobre a conservação da Floresta Ombrófila Mista (FOM), foram avaliadas diferentes intensidades de uso da pastagem, da prática da roçada e do pastejo bovino sobre a regeneração natural. O experimento foi realizado em oito caívas em 2015 e 2016, sendo a regeneração monitorada a cada seis meses. Ao longo desse período foram identificadas 49 espécies arbóreas características da FOM. Independentemente dos fatores avaliados, a regeneração das espécies arbóreas é um processo dinâmico, presente e contínuo nas caívas avaliadas. A intensidade de uso da pastagem não afetou os indicadores de diversidade, a riqueza de espécies e a densidade da regeneração. Houve baixa similaridade entre caívas com o mesmo tipo de manejo do pasto. A roçada foi a atividade de maior impacto sobre a regeneração, com acentuada redução na densidade de regenerantes, embora não tenha afetado a riqueza de espécies. Dada a abundância de espécies na regeneração das caívas, inclusive muitas típicas de estágio avançado, é possível confirmar que estes sistemas apresentam alta resiliência com respeito à conservação da biodiversidade florestal, mesmo com o pastejo do gado há longo tempo. Esses resultados indicam, também, ser possível implementar com sucesso diferentes estratégias de intensificação da pastagem em caívas, desde que estejam associadas à práticas de preservação de áreas mais frágeis e diversas, a fim de compor um sistema com maior sustentabilidade em todas as suas dimensões.

Abstract In some regions of Southern Brazil, historic silvopastoral systems, known as caívas in Santa Catarina State and faxinais in Paraná State, are used in remnants of Araucaria Forest. In these systems, the herbaceous stratum of the forest is composed of natural pasture on which animals graze. In order to better understand the impact of caívas on the conservation of the Araucaria Forest, the effects of different intensities of pasture management, mowing practices, and cattle grazing on natural regeneration were assessed. The experiment was carried out in eight caívas from 2015 to 2016, during which the forest regeneration was monitored every six months. Throughout the study period, 48 tree species that are characteristic of the Araucaria Forest were identified. In all evaluated scenarios, the regeneration of tree species was present, dynamic, and continuous in the caívas. The intensity of pasture use did not affect the indicators of diversity, species richness, and regeneration density. However, there was limited similarity among caívas with the same type of pasture management. Mowing had the greatest impact on regeneration, with a marked reduction in the density of regenerants, although it did not affect species richness. Given the abundance of species in the regeneration, including many species typical of advanced forest succession, it is possible to confirm that these systems present high levels of resilience with respect to the conservation of biodiversity, despite the occurrence of livestock grazing for generations. The results also indicate that it is possible to successfully implement strategies for pasture intensification in caívas. However, this practice must be associated with preservation strategies in forest areas that are more fragile and diverse, in order to ensure the system is sustainable across all dimensions.

RESUMO Os répteis ocupam uma grande variedade de habitats e tipos de ecomorfos, e estão entre os grupos taxonômicos mais sensíveis a perturbações, tais como a fragmentação e perda de habitats. Com o objectivo de avaliar a incidência das modificações da floresta semideciduo, na dinâmica de recuperação após as intervenções de exploração florestal, na utilização de certos recursos, nas comunidades de lagartos e na sua relação com as variáveis da vegetação. Foi utilizado um guia de observação na floresta semideciduo em dois tratamentos com tempos de recuperação pós-logging diferentes em dois sectores do Parque Nacional de Guanahacabibes, Cabo San Antônio e Cabo Corrientes, para determinar as espécies de lagartos, iluminação a que estão expostos, tipo de substrato e altura frequentada por cada indivíduo. Foram identificadas trinta e seis espécies, a utilização de recursos pelas espécies detectadas variou significativamente com o tempo de recuperação pós-colheita para altura e iluminação. As variáveis vegetais que mostraram maior associação com as diferentes espécies de lagartos foram: riqueza de espécies, densidade do estrato arbóreo inferior e altura dos três estratos estabelecidos. As associações estabelecidas entre as mudanças na estrutura florestal e as comunidades de lagartos são significativamente manifestadas pelos estratos de altura e iluminação em ambos os locais e as variáveis vegetais que têm uma maior correspondência são a riqueza do estrato arbustivo, a altura do estrato arbóreo superior e a regeneração natural.

ABSTRACT Reptiles occupy a great variety of habitats and types of ecomorphs, and are among the taxonomic groups most sensitive to disturbances, such as habitat fragmentation and loss. The objective of this study was to evaluate the incidence of changes in the semi-deciduous forest, in the dynamics of recovery after forest harvesting interventions, on the use of certain resources in lizard communities and their relationship with vegetation variables. An observation guide was used in the semi-deciduous forest in two treatments with different post-logging recovery times in two sectors of the Guanahacabibes National Park, Cabo San Antonio and Cabo Corrientes, to determine the lizard species, the illumination to which they are exposed, the type of substrate and the height frequented by each individual. Thirty-six species were identified; the use of resources by the detected species varied significantly with post-harvest recovery time for height and illumination. The vegetation variables that showed the greatest association with the different species of lizards were: species richness, density of the lower tree stratum and height of the three established strata.the associations established between changes in forest structure and lizard communities are significantly manifested by the strata of height and illumination in both locations and the vegetation variables that have a greater correspondence are richness of the shrub stratum, height of the upper tree stratum and natural regeneration.

RESUMEN Los reptiles ocupan una gran variedad de hábitats y de tipos de ecomorfos, se encuentran entre los grupos taxonómicos más sensibles a disturbios, como la fragmentación y pérdida de hábitat. Con el objetivo de evaluar la incidencia de las modificaciones del bosque semideciduo, en la dinámica de recuperación posterior a las intervenciones del aprovechamiento forestal, sobre el uso de ciertos recursos, en las comunidades de lagartos y su relación con las variables de vegetación. Se utilizó una guía de observación en el bosque semideciduo en dos tratamientos con diferentes tiempos de recuperación post aprovechamiento forestal en dos sectores del Parque Nacional Guanahacacbibes, Cabo San Antonio y Cabo Corrientes, para determinar de las especies de lagartos, iluminación a la que se exponen, tipo de sustrato y la altura frecuentada de cada individuo. Se identificaron 36 especies, el uso de los recursos por las especies detectadas varió significativamente con el tiempo de recuperación post aprovechamiento para la altura y la iluminación. Las variables de vegetación que mayor asociación mostraron con las diferentes especies de lagartos fueron: Riqueza de especies, densidad del estrato arbóreo inferior y altura de los tres estratos establecidos. Las asociaciones que se establecen entre los cambios de estructura del bosque y las comunidades de lagartos se manifiestan significativamente por los estratos de la altura y la iluminación en ambas localidades y las variables de vegetación que tienen una mayor correspondencia son riqueza del estrato arbustivo, altura del estrato arbóreo superior y la regeneración natural.

RESUMO Estudos comparativos entre diferentes estratos de florestas em sucessão ecológica são importantes para entender a dinâmica florestal. O estudo avaliou aspectos florísticos, fitossociológicos e ecológicos entre os estratos adulto e regenerante de um fragmento urbano de floresta estacional semidecidual, em Jataí, Goiás. Nas últimas décadas, a vegetação que era tipicamente savânica tem se tornado uma floresta. As árvores adultas (diâmetro a altura do peito, DAP ≥ 5 cm) foram amostradas em 12 parcelas permanentes de 200m². Em cada uma delas, sub-parcelas de 25m² foram amostradas para o estrato regenerante, que compreendeu indivíduos com DAP < 5cm e altura ≥ 1m. Regenerantes tiveram maior riqueza (31 espécies), com duas espécies a mais do que os adultos. Houve baixa similaridade florística e estrutural entre os estratos, indicando uma substituição de espécies ao longo do tempo. A diversidade de Shannon foi significativamente menor para o estrato arbóreo (teste t), visto que apresentou baixa equabilidade, com dominância ecológica de poucas espécies. Ambos os estratos tiveram elevada proporção de espécies pioneiras, quando comparado com outros estudos. Zoocoria e espécies de ambientes florestais foram expressivamente mais abundantes no estrato regenerante. O estudo revelou um fragmento em franco processo de sucessão secundária e vulnerabilidade diante de pressões antrópicas, sendo importante os cuidados quanto à sua conservação.

ABSTRACT Comparative studies between different strata of forests in ecological succession are important to understand the forest dynamics. The study evaluated floristic, phytosociological and ecological aspects between the tree and regenerating strata of an urban fragment of semideciduous forest, in Jataí, Goiás state. In the last decades, the vegetation that was typically savanna has become a forest. Trees (diameter at breast height, DBH ≥ 5 cm) were sampled in 12 permanent 200m² plots. In each of them, 25m² sub-plots were sampled for the regenerant stratum, which comprised individuals with DBH <5cm and height ≥ 1m. Regenerants had greater richness (31 species), with two more species than adults. There was low floristic and structural similarity between the strata, indicating a replacement of species over time. Shannon’s diversity was significantly lower for the tree stratum (t test), since it presented low equability, with ecological dominance of few species. Both strata had a high proportion of pioneer species, when compared to other studies. Zoochory and species of forest environments were significantly more abundant in the regenerating stratum. The study revealed a fragment in a frank process of secondary succession and vulnerability in the face of anthropic pressures, with care regarding its conservation being important.