Seed removal by the squirrel Notocitellus adocetus (Rodentia: Sciuridae) in Western México

Introduction: Seed dispersal and seed predation have important impacts on plant diversity and community structure. Rodents participate in both of these types of interactions. Objectives: To evaluate the removal of the seeds of Crescentia alata, Randia capitata, and Zea mays by the squirrel Notocitellus adocetus to determine how it affects these plant species, by dispersing or preying on their seeds. Methods: We studied 14 individuals for C. alata, 24 for R. capitata, and for Z. mays 35 individuals. We observed foraging and used camera traps to determine the part of the fruit (seed and/or pulp) consumed by the squirrels and the amount of fruit or seed consumed. We also placed fine sand traps (FST) to measure the percentage of seed removal. We quantified the fruits produced by the plant species studied and the percentage of damage caused by N. adocetus throughout the plots. Results: Notocitellus adocetus feeds on the seeds and pulp of C. alata and Z. mays. The species with the highest removal rate and the highest percentage of damage was C. alata. Zea mays was the plant species that had the highest percentage of removal from FST, the largest number of fruits, and the lowest percentage of damage. On FST, R. capitata had the lowest seed remotion. Conclusions: Notocitellus adocetus is considered a seed predator; however, due to its behavior and the characteristics of the fruits of C. alata and R. capitata, this rodent could make the seeds available to secondary seed dispersers.

Introducción: La dispersión y depredación de semillas tienen efectos importantes en la diversidad de plantas y estructura de las comunidades. Los roedores participan en estos tipos de interacciones. Objetivos: Evaluar la remoción de semillas de Crescentia alata, Randia capitata y Zea mays por la ardilla Notocitellus adocetus, para determinar su efecto en estas especies de plantas, dispersando o depredando semillas. Métodos: Estudiamos 14 individuos de C. alata, 24 para R. capitata y 35 individuos para Z. mays. Observamos el forrajeo y usamos cámaras trampas para determinar la parte del fruto (semilla y/o pulpa) consumida y la intensidad de consumo por las ardillas. También colocamos trampas de arena fina (FST) para medir el porcentaje de remoción de semillas. Cuantificamos los frutos producidos por las especies estudiadas y el porcentaje de daño ocasionado por N. adocetus, mediante parcelas. Resultados: Notocitellus adocetus se alimenta de las semillas y pulpa de C. alata y Z. mays. La especie que tuvo mayor tasa de remoción y mayor porcentaje de daño fue C. alata. La especie con mayor porcentaje de remoción, mayor número de frutos y menor daño en las FST fue Z. mays. En las trampas de arena fina, R. capitata tuvo la menor remoción de semillas. Conclusiones: Notocitellus adocetus es considerada depredadora de semillas, no obstante, por su comportamiento y las características de los frutos de C. alata y R. capitata, este roedor podría dejar disponibles las semillas a dispersores secundarios de semillas.

Diversidad de aves en un gradiente altitudinal en la Reserva de la Biosfera Sierra de Manantlán, México / Diversity of birds along an elevation gradient in the Sierra de Manantlán Biosphere Reserve, Mexico

Resumen Introducción: México concentra alrededor del 11 % de las especies de aves del mundo, de las cuales el 20 % son endémicas del país, concentrándose el mayor número en la región occidental. Objetivo: Analizar la composición, diversidad y distribución de la avifauna a lo largo de un gradiente altitudinal en el occidente de México. Métodos: La investigación se realizó en la Reserva de la Biosfera Sierra de Manantlán. Registramos especies de aves vistas o escuchadas en 28 puntos de conteo fijos a lo largo de un gradiente de elevación de 1 000 m. La comparación de la riqueza y la completitud del muestreo se determinaron con curvas de interpolación y extrapolación. Las franjas se compararon con un Procedimiento no Paramétrico de Permutación Multirespuesta. Se usaron correlaciones y ordenaciones indirectas para analizar cambios en la riqueza y abundancia. Resultados: Registramos 129 especies (estimado: 96 % de completitud): 19 endémicas de México, 13 en alguna categoría de riesgo y 21 consideradas indicadoras. La elevación determinó la distribución y abundancia de las especies, y las franjas altitudinales más bajas, tuvieron los valores más altos de riqueza y abundancia. Conclusión: La mayor riqueza y abundancia de especies se registró a menor altitud, con un cambio significativo en la composición y tipo de especies indicadoras por franja.

Abstract Introduction: Mexico concentrates around 11 % of the world's bird species, of which 20 % are endemic to the country, with the highest number concentrated in the Western region. Objective: To analyze composition, diversity and avifaunal distribution along an elevation gradient in Western Mexico. Methods: The research was done in the Sierra de Manantlán Biosphere Reserve. We recorded seen or heard bird species in 28 fixed count points along a 1 000 m elevation gradient. Comparative richness and sampling completeness were determined with interpolation and extrapolation curves. Belts were compared with Non-Parametric Multi-Response Permutation. Correlations and indirect ordinations were used to analyze changes in richness and abundance. Results: We recorded 129 species (estimate: 96 % completeness): 19 endemics to Mexico, 13 in some risk category, and 21 considered indicators. Elevation determined the distribution and abundance of species, and the lower elevational bands, had the highest richness and abundance values. Conclusion: The highest species richness and abundance were recorded at lower elevations, with a significant change in composition and type of indicator species by belt. The numbers of endemic and at-risk species remained constant with elevation.

Variación arquitectónica y morfológica de Hintonia latiflora (Rubiaceae) en relación a la cosecha de corteza y factores ambientales / Architectural and morphological variation of Hintonia latiflora (Rubiaceae) in relation to bark harvest and environmental factors

ResumenHintonia latiflora es una especie ecológicamente rara y económicamente importante del bosque tropical caducifolio de la Cuenca del Balsas, México, cuya corteza se comercializa como medicinal. Las prácticas de descortezado han modificado la forma de las plantas, su arquitectura y morfometría. Se desconoce, si además, existe influencia de factores topogáficos y edáficos sobre estos atributos. Se propone que las condiciones ecológicas en las áreas de distribución y cosecha determinarán las características morfométricas y la variación de la arquitectura de los individuos. Para probar esta hipótesis, evaluamos la relación de factores topográficos y edáficos en diferentes características morfológicas de juveniles (n = 143) y adultos (n = 117) de ocho zonas de cosecha de H. latiflora. Las zonas de cosecha, con una superficie de 0.6 ha, fueron seleccionadas al azar con el apoyo de mapas participativos elaborados por los recolectores del área de estudio. Los datos fueron analizados mediante componentes principales (ACP), y correspondencia canónica (ACC). Los primeros tres CP explicaron el 92.1 % de la variación morfológica; la altura, diámetro basal y cobertura fueron las variables que explicaron las diferencias morfométricas entre juveniles y adultos en las ocho zonas de cosecha. La pendiente del terreno, orientación de la pendiente, profundidad del suelo y pedregosidad, fueron los factores ecológicos estadísticamente relacionados con las diferencias morfométricas. Una menor pendiente, poca pedregosidad, profundidad de suelo, orientación E-O en juveniles (azimut 90˚-270˚) y N-S en adultos (azimuth 0˚-180˚), fueron los factores asociados a mayor altura, número de ramas basales, diámetro basal y cobertura en H. latiflora. Las zonas con mayor intensidad de cosecha estuvieron integradas por árboles monopódicos y algunos individuos basítonos reiterados. Los adultos de estas zonas tuvieron mayor número de frutos. En estos sitios, las plantas de H. latiflora fueron más abundantes y productivas para corteza, pero la alta intensidad de cosecha influyó en la arquitectura vegetal, formando individuos arbustivos multirramificados que originalmente fueron mesótonos. Las áreas con menor intensidad de cosecha estuvieron caracterizadas por pendientes abruptas, suelos superficiales y pedregosos, dominadas por árboles basítonos de menor talla, delgados y escasos en el área. Estos sitios son los menos recomendados para cosecha, debido a que producen menos corteza por árbol, pero sirven para mantener a la especie en el lugar. Con base en estos resultados, podemos desarrollar programas de rehabilitación en áreas afectadas por la explotación comercial, establecer plantaciones forestales en sitios clave para asegurar el desarrollo de individuos con características deseables para cosecha de corteza y contribuir a la conservación in situ de H. latiflora en la Cuenca del Alto Balsas.

AbstractHintonia latiflora is a rare ecologically and economically important species from the Tropical Deciduous Forest of the Balsas Basin, Mexico, whose bark is traded as medicinal. Debarking practices have modified the shape of plants, their architecture and morphometry; but it is unknown if some topographic and edaphic factors may also influence in these attributes. Here we propose that the ecological conditions of this species distribution and harvesting areas, may determine the morphometric characteristics and the individuals variation in their architecture. To test this hypothesis we assessed the relationship of topographic and edaphic factors on the morphological characteristics of saplings (n = 143) and adults (n = 117), in eight harvesting areas of H. latiflora. The harvesting areas, with a surface of 0.6 ha, were selected randomly with the support of participatory mapping elaborated by gatherers of the study site. Data were analyzed using principal components (PCA) and canonical correspondence (CCA) analyses. The first three PC explained 92.1 % of the morphological variation; height, basal diameter, and coverage, explained morphometric differences in both, saplings and adults, in all eight harvesting zones. The terrain slope, slope orientation, soil depth and stoniness, were ecological factors statistically related with morphometric differences. A lower terrain slope, little stoniness, soil depth, slope orientation E-W in saplings (azimuth 90˚-270˚) and N-S in adults (azimuth 0˚-180˚) were the factors associated to height, number of basal branches, basal diameter and coverage of H. latiflora. Areas with higher harvesting intensity were composed by monopodic trees and some reiterated basitone individuals; the adults of these areas also had more fruits. At these sites, plants of H.latiflora were more abundant and produced more bark, but the high-intensity of harvesting, changes plant architecture, forming shrubby, multi-stemmed individuals, that originally were mesotone trees. Areas with lower harvesting intensity were characterized by steep slopes, shallow and rocky soils, and were dominated by basitone trees of smaller size, thin and scarce in the area. These sites are the least recommended for harvesting, because they produce less bark per tree, and serve to preserve the species at the site. Based on these results, we can develop restoration programs in areas affected by commercial harvesting, establish forestry plantations in key sites to ensure the establishment and development of individuals with desirable characteristics for bark harvesting and contribute to in situ conservation of H. latiflora in the Alto Balsas Basin. Rev. Biol. Trop. 65 (3): 900-916. Epub 2017 September 01.

Diagnóstico ecológico para la conservación de Jatropha spp. (Euphorbiaceae) y sus hábitats, en la Reserva Tehuacán-Cuicatlán, México / Diagnosis for the ecological conservation of Jatropha spp. (Euphorbiaceae) and their habitats in the Tehuacan-Cuicatlan Reserve, Mexico

Jatropha spp. is an important phytogenetic resource used as food, medicine, and biofuel. In this study, we verified the taxonomic identity of Jatropha species for The Biosphere Reserve Tehuacan-Cuicatlan, and the Ecological Land Units (ELU) occupied by them. We assessed the conservation status of their habitats, and the vulnerability of Jatropha spp. populations. A total of 15 sampling sites were selected in the Reserve. The taxonomic work was based on specimens, original descriptions and type material from herbaria and those available on-line. ELUs were classified using biophysical variables, and gvSIG software. Ecological attributes were determined using a quantitative analysis by the point-centered quarter method; disturbance was estimated through site indicators, and the conservation status of the Jatropha populations was assessed using the Method for Evaluation of the Risk of Extinction of Plants in Mexico (MER). Jatropha frequently dominated the physiognomy of plant communities. The current distribution of Jatropha species in the Reserve was mainly determined by elevation, temperature, and precipitation variables. The confirmed species were Jatropha ciliata Sessé ex Cerv., Jatropha neopauciflora Pax, Jatropha oaxacana J. Jiménez Ram. & R. Torres, Jatropha rufescens Brandegee, and Jatropha rzedowskii J. Jiménez Ram., which are distributed in four of the six defined ELU. J. neopauciflora and J. rzedowskii were the most widespread species; this last species concur in four, J. oaxacana in two, while J. rufescens and J. ciliata in one ELU, being the most restricted. The richness of the genera in the associated communities ranged from 16 to 42. The maximum and minimum importance Value indexes were observed in San Nicolas Tepoxtitlan for J. neopauciflora (53.75%) and J. rzedowskii (1.50%). The disturbance index varied from 0.22 to 0.82, with an average of 0.51, where the livestock variable had a high contribution. Considering the risk categories of MER, we concluded that J. oaxacana requires special protection, and J. ciliata and J. rufescens were species under extinction risk. The conservation status of the plant communities inhabited by populations of Jatropha spp. was moderate, taking into account the rate of disturbance. The main factors affecting the habitats of Jatropha were livestock and human activities; the floristic composition of the surrounding plant communities has low richness. These results support the urgent need of conservation strategies to avoid the loss of important wild growing species of Jatropha populations. Rev. Biol. Trop. 63 (1): 23-33. Epub 2015 March 01.

Jatropha spp., es un importante recurso fitogenético usado como alimento, medicina y biocombustible. En este estudio verificamos la identidad taxonómica de las especies de Jatropha para la Reserva de la Biosfera Tehuacán-Cuicatlán, y las unidades ambientales (UA) que ocupan. Evaluamos el estado de conservación de sus hábitats y la vulnerabilidad de las poblaciones de Jatropha. Los sitios de muestreo seleccionados en la Reserva fueron 15. El trabajo taxonómico estuvo basado en especímenes, descripciones originales y material tipo de herbarios y aquellos en línea. Las UA fueron clasificadas mediante variables biofísicas y el software gvSIG. Los atributos ecológicos fueron determinados con análisis cuantitativo por el método de cuadrado centrado en un punto; el disturbio fue estimado a través de indicadores de sitio, y el estado de conservación de las poblaciones de Jatropha con el Método para la Evaluación de Riesgo de Extinción de Plantas en México (MER). Jatropha frecuentemente dominó la fisonomía de las comunidades vegetales. La distribución actual de las especies de Jatropha en la Reserva estuvo principalmente determinada por las variables altitud, temperatura y precipitación. Las especies confirmadas fueron: Jatropha ciliata Sessé ex Cerv., Jatropha neopauciflora Pax, Jatropha oaxacana J. Jiménez Ram. & R. Torres, Jatropha rufescens Brandegee, y Jatropha rzedowskii J. Jiménez Ram., las cuales estuvieron distribuidas en cuatro de las seis UA definidas. J. neopauciflora y J. rzedowskii son las especies más ampliamente distribuidas; estas últimas especies concurrieron en cuatro, J. oaxacana en dos, mientras que J. rufescens y J. ciliata en una UA, siendo ésta la especie más restringida. La riqueza de géneros en las comunidades asociadas varió entre 16 y 42. Los máximos y mínimos Índices de Valores de Importancia fueron observados en San Nicolás Tepoxtitlan para J. neopauciflora (53.75%) y J. rzedowskii (1.50%). El índice de disturbio varió entre 0.22 y 0.82, con promedio de 0.51, mientras que la variable ganado tuvo mayor contribución. Considerando las categorías de riesgo del MER, concluimos que J. oaxacana requiere protección especial, mientras que J. ciliata y J. rufescens fueron especies en riesgo de extinción. El estado de conservación de los hábitats ocupados por poblaciones de Jatropha spp. es moderado, tomando en cuenta la tasa de disturbio. Los principales factores que afectan a los hábitats de Jatropha son el ganado y las actividades humanas; la composición florística de las comunidades vegetales tuvo baja riqueza. Estos resultados apoyan la necesidad de establecer estrategias de conservación para evitar la pérdida de importantes poblaciones silvestres de Jatropha.

Dinámica poblacional, selección de sitios de percha y patrones reproductivos de algunos murciélagos cavernícolas en el oeste de México / Population dynamics, roost selection and reproductive patterns of some cave bats from Western of Mexico

Almost half of bat species that occur in Mexico use caves as permanent or temporal roosts. However, the ecological studies about cave bat communities are scarce. In this work we studied the population dynamics, roost selection and reproductive patterns of some bats present in El Salitre Cave, Colima, Mexico. We carried out monthly samplings between August 2003-March 2005 using a harp trap for bats capture, we took their bio- logical data and marked some of them with plastic rings. We also explored the cave to locate bat colonies and register microclimatic conditions in each cave section. We captured a total of 16 409 bats of which 31% were Mormoops megalophylla, 24.5% Pteronotus personatus, 23% P. davyi, 8.2% P. parnellii, 5.8% Natalus mexicanus and 5.3% Glossophaga soricina. Macrotus waterhousii, G. morenoi, Desmodus rotundus, Balantiopteryx plicata, and Glyphonycteris sylvestris represented only 2.2% of the captures. Some bat species used the cave as a permanent day roost while others as a seasonal one, and their population size varied markedly along the year and between rainy and dry seasons. Most bat population peaks were linked with their reproductive periods. The Pteronotus species and N. mexicanus exhibited sexual segregation during the breeding season. The mormoopids and N. mexicanus occupied deeper parts of the cave with temperatures >25.8°C and relative humidity >99%. The phyllostomids occupied intermediate sections where the ambient was less hot and humid, with temperatures of 23.2-28.3°C and humidity of 74-89.9%. Some individuals of B. plicata and G. sylvestris were seen occasionally occupying one chamber near the entrance two, where temperature and humidity were of 23.2°C and 84.2%, respectively. The mormoopids and N. mexicanus showed a pattern of seasonal monoestry, synchronized with rainy season. Glossophaga soricina had a pattern of bimodal seasonal poliestry, with one reproductive peak to early of dry season and another to last of this season. Macrotus waterhousii did not exhibit a seasonal pattern, with parturitions occurring throughout the year. Our results indicate a seasonal replacement between several species as well as seasonal movements to other caves. The data indicate that the carrying capacity of the cave is mainly determined by the availability of roosting sites. The selection of roosting sites is linked to the close relationship between microclimatic conditions and the species physiological characteristics. The reproduction of mormoopids and N. mexicanus was mostly influenced by rainfall which determinates food availability.

Estudiamos la ecología poblacional y reproducción de algunas especies de murciélagos presentes en una cueva del oeste de México. Entre agosto 2003-marzo 2005 capturamos 16 409 individuos de los cuales 86.7% pertenecieron a miembros de la familia Mormoopidae, 7.4% a Phyllostomidae, 5.8% a N. mexicanus y 0.1% a B. plicata. Los números poblacionales de las especies varían notablemente a lo largo del año y entre temporadas. Segregación sexual durante la época reproductiva sucede en Pteronotus y N. mexicanus. Los mormópidos y N. mexicanus ocuparon las partes más profundas de la cueva donde imperan temperaturas >25.8°C y humedad >99%. Los filostómidos ocuparon las secciones intermedias con temperaturas de 23.2-28.3°C y humedad de 74-89.9%; B. plicata y G. sylvestris ocuparon una cámara con temperatura de 23.2°C y humedad del 84.2%. Los mormópidos y N. mexicanus exhibieron un patrón monoéstrico estacional, G. soricina presentó un patrón poliéstrico bimodal estacional y M. waterhousii exhibió un patrón reproductivo continuo. Nuestros resultados indican un reemplazamiento estacional entre varias especies, así como movimientos estacionales hacia otras cuevas. La selección de los sitios de percha esta ligada a las condiciones microclimáticas del refugio y la fisiología de las especies. La reproducción de las especies insectívoras esta influida por la precipitación que determina la disponibilidad del alimento.

Plant functional traits with particular reference to tropical deciduous forests: A review.

Functional traits (FTs) integrate the ecological and evolutionary history of a species, and can potentially be used to predict its response as well as its influence on ecosystem functioning. Study of inter-specific variation in the FTs of plants aids in classifying species into plant functional types (PFTs) and provides insights into fundamental patterns and trade-offs in plant form and functioning and the effect of changing species composition on ecosystem functions. Specifically, this paper focuses on those FTs that make a species successful in the dry tropical environment. Following a brief overview, we discuss plant FTs that may be particularly relevant to tropical deciduous forests (TDFs). We consider the traits under the following categories: leaf traits, stem and root traits, reproductive traits, and traits particularly relevant to water availability. We compile quantitative information on functional traits of dry tropical forest species. We also discuss trait-based grouping of plants into PFTs. We recognize that there is incomplete knowledge about many FTs and their effects on TDFs and point out the need for further research on PFTs of TDF species, which can enable prediction of the dynamics of these forests in the face of disturbance and global climate change. Correlations between structural and ecophysiological traits and ecosystem functioning should also be established which could make it possible to generate predictions of changes in ecosystem services from changes in functional composition.

Diversidad de aves de hábitats naturales y modificados en un paisaje de la Depresión Central de Chiapas, México

Bird biodiversity in natural and modified habitats in a landscape of the Central Depression of Chiapas, Mexico. In many parts of the neotropics, the original habitats are rapidly changing because of excessive logging, agriculture and livestock activity, with an often negative impact on bird communities. I present an analysis of the diversity and richness of birds in a fragmented landscape of the Central Chiapas Depression. Fieldwork was conducted from February 2003 to January 2004. Using point counts, a total of 35 families and 225 bird species were registered (164 residents and 61 migratory); 3% are abundant and 30% rare. Diversity, species richness and number of individuals were significantly higher in tropical deciduous forest (H´=3.41, 178 species ANOVA p<0.0001), which also had the greatest number of species restricted to a single vegetation type (39 species). The incorporation and maintenance of natural and modified habitats are necessary for the survival and reproduction of many birds species in the study area. Rev. Biol. Trop. 58 (1): 511-528. Epub 2010 March 01.

Se presenta un análisis de la diversidad y riqueza de aves en un paisaje fragmentado en la Depresión Central de Chiapas. El trabajo de campo se realizó de febrero de 2003 a enero de 2004. Se utilizó el método de conteo por puntos, registrando un total 35 familias y 225 especies de aves. Del total de especies registradas 164 son residentes y 61migratorias. El 3% de las especies son abundantes y el 30% son raras. Se presentaron diferencias significativas en la diversidad, riqueza de especies y número de individuos entre los hábitats de estudio (ANOVA p<0.0001). La diversidad y riqueza de especies fue significativamente mayor en el bosque tropical caducifolio (H´=3.41, 178 especies), presentando también el mayor número de especies exclusivas (39). La incorporación y mantenimiento de hábitats naturales y modificados son necesarios para la supervivencia y reproducción de muchas especies de aves en el área de estudio.

Bird diversity and conservation of Alto Balsas (southwestern Puebla), Mexico

Knowledge of the composition of the bird community in Alto Balsas (southwestern Puebla, Central Mexico) is needed for management programs aiming at protection and conservation of bird species and their habitats I studied sites with tropical deciduous forest. Data were obtained during 1666 hours of field work in 238 days from March 1998 to September 2000. Six permanent transect (3.5 km long and 100 m wide; 30 to 40 ha in each transect) were used to determine species richness in the study sites. The Shannon-Wiener diversity index was calculated for each site and Sorensen's index was used to assess similarity between sites. One-way analysis of variance was used to test for differences between sites in species richness and diversity values. A total of 128 species were recorded, Tepexco (n=75, H' = 3.76) and Puente Márquez (n=61, H' = 3.62) were the sites that showed the greatest specific richness and diversity. However, species richness and diversity seasonally patterns were similar among sites (ANOVA p > 0.05), with highest diversity during the rainy season. Most species were resident; 42 were migrants. The avifauna was represented by 30 species associated with tropical deciduous forest and 12 from open habitats or heavily altered habitats. Insectivores were the best represented trophic category, followed by carnivores and omnivores.