Efecto de la perturbación del bosque en la tasa de visitas de murciélagos polinizadores y sus consecuencias sobre el éxito reproductivo y sistema de apareamiento en árboles de la familia Bombacaceae.

La fragmentación y la perturbación del bosque pueden tener efectos deletéreos sobre el éxito reproductivo y el sistema de apareamiento de los árboles tropicales, además de modificar el compartimiento de sus polinizadores. Los objetivos de este capítulo son: (1) evaluar el efecto de la perturbación del bosque sobre la tasa de visita de los murciélagos a cuatro especies de árboles de Bombacaceas; (2) comparar el éxito reproductivo entre árboles en áreas perturbadas y en bosques continuos; (3) determinar las consecuencias de un cambio en la tasa de visitas de los polinizadores sobre el éxito reproductivo de los árboles; y (4) documentar cómo los patrones de visita de los polinizadores pueden afectar el sistema de apareamiento de las plantas que polinizan. Se estudiaron cuatro especies de árboles de la familia Bombacaceae en los bosques tropicales de Jalisco, México, y en las regiones de Guanacaste y la Península de Osa, en Costa Rica. Los murciélagos nectarívoros fueron los únicos polinizadores efectivos para estas cuatro especies. Las flores de Ceiba grandiflora en el bosque recibieron más visitas por parte de Glossophaga soricina; no se observaron diferencias en el número de visitas por parte de Leptonycteris curasoae y Musonycteris harrisoni solo visitó flores dentro del bosque. Ceiba aesculifolia presentó una mayor tasa de visitas en los sitios perturbados, tanto por G.. soricina como por L. curasoae. Ceiba pentandra, en Chamela, no presentó diferencias en la tasa de visitas de G. soricina entre áreas perturbadas y bosque continuo, pero L. curasoae visitó una mayor cantidad de flores en bosque continuo. En Guanacaste, C. pentandra recibió más visitas de Phyllostomus discolor que de G presentó una mayor producción de flores en fragmentos y no hubo diferencias en la proporción de frutos por flor (fruto/flor). Ceiba grandiflora no presentó diferencias en la producción de flores, pero la razón fruto/flor fue mayor en el bosque. Pachira quinata presentó un patrón similar a C. aesculifolia en cuanto a la producción de flores, pero la razón fruto/flor fue mayor en los árboles de bosque continuo. Estas cuatro especies de Bombacaceae son predominantemente autoincompatibles. Los niveles de exocruzamiento fueron independientes del tipo de hábitat para C. aesculifolia, C. grandiflora y C. pentandra en Guanacaste; sin embargo, los árboles C. pentandra, en la Península de Osa, mostraron un sistema de apareamiento mixto. Los efectos de la perturbación del bosque sobre la polinización por murciélagos, la reproducción de plantas y sus patrones de apareamiento varían según la especie de Bombacaceae y su historia de vida.Forest fragmentation and disturbance can have negative effects on the reproductive success and mating systems of tropical trees, in addition to modifying the behavior of the pollinators that pollinate them. The objectives of this study are: (1) to evaluate the effect of forest disturbance on bat pollinator activity for four bombacaceous species; (2) to compare reproductive success between trees found in disturbed habitats and continuous forest; (3) to determine the consequences of a change in bat pollinator activity on plant reproductive success; and (4) to document how bat pollinator activity may affect breeding systems in the plants they pollinate. Four species from the Bombacaceae family were studied in the tropical forests of Jalisco, Mexico, and in the areas of Guanacaste and Peninsula de Osa, in Costa Rica. Nectarivorous bats were the only effective pollinators observed for these four species. Flowers from Ceiba grandiflora in the forest received more visits from Glossophaga soricina. No differences were observed for Leptonycteris curasoae and Musonycteris harrisoni was only observed visiting flowers in the forest. Flowers from C. aesculifolia in fragmented habitats received more visits from both G. soricina and L. curasoae. For C. pentandra in Chamela no differences in visits were observed for G. soricina between disturbed areas and continuous forest, but L. curasoae visited more flowers in continuous forest. In Guanacaste, C. pentandra received more visits from Phyllostoumus discolor than G. soricina, and in Osa no bat visits were observed. Ceiba aesculifolia produced more flowers in disturbed areas but no differences were observed for fruit set. Ceiba grandiflora showed no differences in flower production but fruit set was greater in the forest. Similar to C. grandiflora, Pachira quinata showed no differences in flower production, however, greater fruit set was observed in continuous forest. These four bombacaceous species are predominantly self-incompatible. Out-crossing rates were independent of habitat for C. aesculifolia, C. grandiflora, and C. pentandra en Guanacaste; however, C. pentandra trees from the Osa Peninsula showed a mixed breeding system. Our results show that the effects of forest disturbance on bat pollination, plant reproductive success and breeding system varied depending on the bombacaceous species and its life history characteristics.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Mating system and female reproductive success of the endemic and endangered epiphyte Rhynchostele cervantesii (Orchidaceae) in a cloud forest in Michoacan, Mexico

Background and aims – The Orchidaceae family is vulnerable, because of the destruction of their habitat, as well as the extraction of individuals from natural populations. This is the case of the genus Rhynchostele Rchb.f.; among the actions considered important for appropriate conservation strategies for this genus is the generation of fundamental knowledge, such as on its reproductive biology. The objective of this work is to understand the mating system and reproductive success of Rhynchostele cervantesii, an endangered epiphytic orchid endemic to Mexico.Material and methods – Manual and open-pollination treatments were conducted during 2014 and 2015 in a cloud forest in Michoacan, Mexico. In each period, 30 to 40 randomly selected inflorescences were subjected to the following treatments: a) spontaneous-self-pollination, b) emasculation, c) self-pollination, d) cross-pollination, and e) open-pollination. The developed fruits were counted and harvested, the viability of the seeds was determined, through the observation and evaluation of embryos using microscopy.Key results – Significant differences were recorded between the treatments in both 2014 and 2015, with higher fruit production in cross-pollination than in self-pollination and natural-pollination. There were significant differences in seed viability, with higher values for seeds from open-pollination and cross-pollination and lower values for seeds from self-pollination.Conclusions – Rhynchostele cervantesii is a species that requires pollinators for sexual reproduction because there is no fruit production with spontaneous-self-pollination. Under pollen limitation, the fruit set of natural pollination was a lot lower than in cross-pollination although fruits were the same quality. R. cervantesii had a mixed mating system with a tendency to exogamy, presenting high values of female reproductive success compared to other tropical epiphytic orchid species reported in the literature

Reproductive Success and Inbreeding Differ in Fragmented Populations of Pinus rzedowskii and Pinus ayacahuite var. veitchii, Two Endemic Mexican Pines under Threat

Seed production, quality, germination and seedling establishment are indicators of reproductive success in conifers. Monitoring of these parameters is essential to determine the viability of populations for the purposes of conservation. We analyze cone and seed traits as indicators of reproductive success in the endangered Rzedowski´s pine (Pinus rzedowskii (Madrigal et Caballero) and near-threatened veitchii pine (Pinus ayacahuite var. veitchii (Shaw)) in west-central Michoacán, Mexico. These traits were systematically quantified and their variation assessed using Generalized Linear Mixed Models (GLMMs). We found that the reproductive success of Rzedowski’s pine seems to be critical, presenting low seed efficiency (17.10%), germination (5.0%) and seedling establishment (27.7%), with high levels of inbreeding (0.79). In contrast, veitchii pine presents moderate seed efficiency (54.9%), high germination (71.5%) and seedling establishment (84%–97%) and low inbreeding (0.33). Reproductive indicators differed significantly among zones and populations for each species, where fragment sizes mainly affected seed production and efficiency. This result indicates that fragmentation has played a more important role in the reproductive success of Rzedowski’s pine than in veitchii pine, perhaps by limiting pollen flow among zones and populations and producing higher levels of inbreeding and lower seed efficiency in the former species. We propose a conservation strategy for these important pine species in order to increase their long-term genetic viability

Effects of environmental factors over aquatic hemimetabola and Coleoptera diversity in the Xichu’s basin, Guanajuato, México

Los sistemas lóticos integrados por cauces temporales representan una alta proporción de las aguas continentales del planeta, no obstante se encuentran entre los sistemas menos estudiados a nivel mundial. En cuanto a diversidad entomológica, el centro de México -donde se ubican estos sistemas- permanece poco estudiado a pesar del alto potencial que presenta la zona de albergar una alta diversidad y de los vínculos importantes que este grupo desempeña en los flujos de energía de los ecosistemas acuáticos. El objetivo del presente trabajo fue analizar las variables ambientales que determinan los cambios en la diversidad y las escalas en que tienen efecto, en las comunidades de insectos acuáticos de un sistema fluvial semiárido del centro de México. Se registraron un total de 89 géneros, con el orden Coleoptera presentando la mayor riqueza. Los valores más altos de diversidad alfa se encontraron sobre sitios permanentes en la temporada de sequía (1D:10.63), lo que se atribuye a la mayor estabilidad que presentan los sistemas fluviales en esta temporada. Las comunidades establecidas sobre cauces permanentes e intermitentes presentaron baja similitud (Ij <0.45), indicando un alto recambio entre comunidades establecidas sobre cauces con diferente hidroperiodo. Los análisis de distribución (“partición”) de la diversidad indican que el mayor aporte a la diversidad regional se da por cambios en la composición de géneros a nivel de ríos (37%), entre temporadas (22%) y por el tipo de sistema (21%). De acuerdo con el Análisis de Correlación Canónica las variables de mesohábitat, velocidad de corriente, calidad ecológica y orden del cauce son las que mejor explican la variación en la presencia de los taxones. Los resultados sugieren que los sitios permanentes se encuentran actuando como fuente de especies de los sitios intermitentes y que los esfuerzos de conservación en la región deben implementarse a escala de paisaje.Lotic systems, in particular temporal streams, represent an important proportion of continental waters, but are poorly studied. This is particularly clear in central Mexico, where temporal streams are abundant and remain poor studied despite their great potential for high diversity and the important energy within these ecosystems. The aim of this study was to analyze the environmental variables and scales at which these variables have effects on aquatic insect assemblages in a semiarid fluvial system in Central Mexico. A total of 89 genera were registered, the order Coleoptera showing the highest richness. Peak values for alpha diversity were found on permanent sites in the dry season (1D=10.63), the more stable environment in permanent streams during the dry season might accounted for this pattern. Assemblages at our study sites showed low similarity (Ij < 0.45) indicating high genera replacement among sites, possibly related to differences in hydroperiod. Partition analysis indicates that variation in genera composition among rivers contributed a large proportion of the diversity (37%). Results from the canonical correspondence analysis point to mesohabitat, velocity, ecological quality, and hydrological order, as the most important variables explaining diversity patterns. In addition, hydrological condition and intermittency were important factors related to diversity (~21-22%). The results suggest that permanent sites function has species sources for intermittent sites, highlighting the need for conservation planning at the landscape level in the Xichu’s basin. Rev. Biol. Trop. 62 (Suppl. 2): 69-80. Epub 2014 April 01

Human impacts on pollination, reproduction and breeding systems in tropical dry forest plants

Over the last two decades several studies have shown that plant species of contrasting life-forms ranging from small herbs to large trees may experi-ence a decline in reproductive success following habitat fragmentation and population disruption (Bawa 1990; aizen and Feinsinger 1994; aguilar et al. 2006). Such outcome has been shown for many plants throughout the tropics, particularly trees, where human activities have resulted in elevated rates  of  habitat  fragmentation  and  degradation  (Ghazoul  and  Shaanker 2004; Quesada and Stoner 2004; Quesada et al. 2004). Because almost 90 percent of angiosperms (i.e., flowering plants) depend on animals for effec-tive pollination and sexual reproduction (Buchmann and Nabhan 1996), it is of central concern to understand the capacity of pollinators for transfer-ring pollen among individuals and its consequences on plant reproduction in newly created anthropogenic landscapes.While  evolutionary  dependence  of  plants  on  animal  mutualists  for sexual  reproduction  has  improved  pollen  transfer  to  stigmas,  it  has  also prompted increased plant susceptibility to fragmentation and other forms of anthropogenic disturbance that characterize today?s landscapes (e.g., ai-zen et al. 2002; ashworth et al. 2004). Changes in abundance, composi-tion, and/or foraging behavior of pollinators as a consequence of habitat disturbance will have an effect on the amount and/or quality (autogamous 174   seasonally dry tropical forestvs. xenogamous) of pollen deposited on stigmas, thus affecting reproduc-tion and the genetic structure of plants (Wilcock and Neiland 2002). Much research has been conducted with regard to the effects of habitat loss and fragmentation on pollination, plant reproduction, and genetic di-versity of plant populations over the past 20 years. Nevertheless, there has been certain research bias in the selected natural systems evaluated, where species from tropical forests represent only 16 percent of the entire studied species around the world (aguilar et al. 2006, 2008). Moreover, no specific analysis of this subset of species has yet been conducted. this comparative underrepresentation of tropical plant species in fragmentation studies high-lights the need to focus more thoroughly on population studies from these threatened and fragile habitats.Some expected outcomes of habitat fragmentation include local extinc-tion of plant and animal populations, the alteration of species richness and abundance,  and  changes  in  the  trophic  structure  of  communities. these negative effects of habitat fragmentation can be expressed at the landscape and population levels. at the landscape scale, fragmentation involves the transformation of a large area of habitat into several patches of smaller size, isolated from each other by surrounding anthropogenic habitats different from the original. Such loss and breaking apart of the habitat alters nega-tively the connectivity, functioning, and biodiversity within the matrix of the fragmented habitat (Fahrig 2003). at the population level, habitat frag-mentation may reduce the effective population size and the magnitude and direction of gene flow, which in turn would produce negative changes in the population and genetic structure of plant species (Young et al. 1996; aguilar et al. 2008). the reduction of both gene flow and effective popula-tion size by habitat fragmentation may cause inbreeding, genetic drift, and a  consequent  decline  of  genetic  variation.  therefore,  the  loss  of  genetic diversity may limit the ability of local populations to respond selectively to varying local conditions, compromising their persistence and increasing their risk of extinction due to inbreeding depression. Habitat fragmentation may not only lead to a reduction in population size  and  genetic  variation  but  also  disrupt  key  interactions  of  the  plants with their pollinators and seed dispersers. the interaction between plants and  pollinators  can  be  disrupted  by  habitat  loss, reduction  of  pollinator abundance, changes in floral resource availability and distribution, or com-petitive exclusion from floral resources by inefficient or exotic pollinators. Most of the plant-pollinator interactions may depend on the relative abun-dance of floral resources, thus changes in plant abundances caused by forest disturbance may lead to modification in the composition, functioning, and Human Impacts on Pollination, reproduction, and Breeding Systems  175 maintenance of plant-pollinator webs (aizen and Feinsinger 2003; Lope-zaraiza et al. 2007). We should expect small isolated or fragmented plant populations to be less attractive to pollinators than large populations. as a result of this, rates of pollinator visitation and seed production may often be lower in small than in large populations of plants pollinated by animals. the negative consequences of habitat fragmentation for plant popula-tions could be exacerbated by the complex interactions of reproductive (sex expression) and mating systems (selfing vs. outcrossing or mixed strategies) in combination with population size and pollination and seed dispersal sys-tems. Previous studies of seasonally dry tropical forests (SDtFs) indicate that  the  reproduction  of  plants  is  dependent  on  the  presence  of  natural pollinators (Frankie et al. 1974; Bullock 1985). therefore, changes in the abundance and activity patterns of pollinators induced by habitat fragmen-tation are expected to reduce gene flow between isolated plant populations. the negative effects of forest fragmentation on the viability of populations could be particularly noticeable in tropical tree species that posses self-in-compatibility systems and depend on pollinators for sexual reproduction (Bawa 1974, 1990; aguilar et al. 2006). Disturbances that impact animal vectors of pollen transfer may therefore affect the reproductive output of tropical trees. Pollination of tropical plants is mainly conducted by animal vectors such as bees, butterflies, flies, birds, and bats, and the natural popu-lations of these animals inhabit and depend on the existence of forests.the objectives of this chapter are to (1) evaluate the effects of forest fragmentation on plant-pollinator interactions, plant phenology, reproduc-tive dynamics, and genetic parameters of tropical plants; (2) describe and compare plant life-history traits, pollination systems, and plant reproduc-tive traits between tropical forests; and (3) predict vulnerability patterns to forest fragmentation based on ecological and reproductive traits of plants.Fil: Quesada, Mauricio. Universidad Nacional Autónoma de México; MéxicoFil: Rosas, Fernando. University of California; Estados UnidosFil: Aguilar, Ramiro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Ashworth, Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Rosas Guerrero, Víctor. Universidad Nacional Autónoma de México; MéxicoFil: Sayago, Roberto. Universidad Nacional Autónoma de México; MéxicoFil: Lobo, Jorge. Universidad de Costa Rica; Costa RicaFil: Herrerías Diego, Yvonne. Universidad Nacional Autónoma de México; MéxicoFil: Sanchez Montoy, Gumersindo. Universidad Nacional Autónoma de México; Méxic

Correction to: Historical biogeography reveals new independent evolutionary lineages in the Pantosteus plebeius-nebuliferus speciesgroup (Actinopterygii: Catostomidae)

Following publication of the original articl

Historical biogeography reveals new independent evolutionary lineages in the Pantosteus plebeius-nebuliferus species-group (Actinopterygii: Catostomidae)

[Background]: The Pantosteus plebeius-nebuliferus species-group is a group of freshwater fishes distributed in endo- and exorheic drainage basins in the Mexican Sierra Madre Occidental mountain range system and central North Mexico. The geological history of this region is considered an important factor in explaining the evolutionary history of low vagility animals like freshwaters fishes. The aim of this study was to examine the phylogenetic relationships and describe the evolutionary history of the species-group. We hypothesized that the genetic structure and distribution of the main clades of Pantosteus plebeius-nebuliferus are associated with the geological history of Northern Mexico. To this end, we obtained DNA sequences of mitochondrial and nuclear genes and performed phylogenetic and phylogeographic analyses. Divergence time estimation and ancestral area reconstruction were also carried out to propose a biogeographical hypothesis, and species boundaries within the species-group were also tested.[Results]: We identified four clades within the Pantosteus plebeius-nebuliferus species-group in both markers. Divergence ranged from 5.9% to 9.2% for cytb and 0.1% to 0.9% for GHI. We observed significant genetic structure and no shared haplotypes between clades. We estimated that the clades diverged during the last 5.1 Myr, with a biogeographic scenario suggesting eight vicariant and four dispersal events through the historic range of the species-group. We found that the best species-delimitation model is when four species are assumed, which correspond to the main clades. We identified nine evolutionary significance units (ESUs), pertinent to the conservation of the group, each representing populations present in distinct drainage basins.[Conclusions]: The evolutionary history of the Pantosteus plebeius-nebuliferus species-group is characterized by vicariant post-dispersal processes, linked to geological changes in the Sierra Madre Occidental and central Northern Mexico since the Pliocene. This is congruent with biogeographic patterns described for other co-distributed fish species. We propose a new phylogenetic hypothesis for the species-group, clarifying the taxonomy of this evolutionarily complex group. Our results suggest that the species-group consists of at least four clades with independent evolutionary histories, two of which may represent new undescribed species. Our identification of ESUs provides a basis upon which conservation measures can be developed for the species-group.This work was partial supported by the Coordinación de la Investigación Científica (CIC-UMSNH 2014), the Ministerio de Economía y Competitividad of Spain (grant reference CGL2013-41375-P). Both resources were used to finance fieldwork, laboratory (DNA isolation and amplification of molecular markers) and sequencing service, as well as for the publication of this work. The Consejo Nacional de Ciencia y Tecnología CONACYT with sabbatical grant and the scholarship to ODD (grant number: 260596) and DKCS (number grant: 254270/411621) respectively

Factors affecting phenological patterns of bombacaceous trees in seasonal forests in Costa Rica and Mexico

We compared phenological patterns of tree species of the family Bombacaceae in three seasonal forests in Mexico and Costa Rica whose dry seasons vary in duration and intensity. The objectives were to (1) determine intraspecific variation in phenology between sites in different geographic locations with different precipitation regimes, (2) compare interspecific phenological patterns within sites during one year, and (3) document seasonal pollinator use of floral resources at one site in relation to the flowering phenology of these species. To determine the sequence of phenological events in trees of the family Bombacaceae across three study sites, phenology of marked individuals was recorded every 2 wk from September 2000 through August 2001 for six species. To estimate the importance of bombacaceous species in the diet of nectarivorous bats, pollen samples were collected from the bodies or feces of bats once every 2 wk during flowering. Our study suggests that phenological patterns of the Bombacaceae family in Neotropical dry forests are mainly constrained by phylogenetic membership and adaptive selective pressures associated with competition for pollinators. Abiotic factors related to precipitation and soil water content appear to be regulating leaf flushing and abscission, but the principal causes of flowering are related to ultimate factors associated with competition for pollinators. This study is the first that evaluates the phenological pattern of species and genera of the same family at different latitudes in a similar life zone.Consejo Nacional de Ciencia y Tecnología, MéxicoDirección General de Asuntos del Personal Académico at the Universidad Nacional Autónoma de MéxicoInternational Foundation for ScienceVicerrectoría de Investigación from the Universidad de Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí