Repositorio Institucional de INECOL (Instituto de Ecología)
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Ungulate biomass across a rainfall gradient: a comparison of data from neotropical and palaeotropical forests and local analyses in Mexico
Get PDFUsing a data set from 36 studies, we evaluated variation in ungulate biomass across a rainfall gradient using polynomial models, aiming to: (1) compare neotropical and palaeotropical dry and wet forests as well as African savannas; and (2) evaluate the usefulness of polynomial models to predict ungulate biomass at neotropical sites using data from a dry forest (Chamela-Cuixmala Biosphere Reserve, CCBR) and a wet forest (Montes Azules Biosphere Reserve, MABR) in Mexico. Our results showed that an overestimation of expected ungulate biomass can be obtained for some tropical forests if data from African savannas are included in the model. This overestimation was particularly high for predicted ungulate biomass in neotropical dry forests. These ecosystems sustain different ungulate biomass values even when rainfall is similar. This was particularly true for some tropical dry forests and savannas. Rainfall predicted the expected ungulate biomass in neotropical ecosystems relative to that of palaeotropical ones under similar precipitation regimes, but did not correctly predict the observed ungulate biomass at local level if data outside the Neotropics are included in the model. This was more evident when we compared observed biomass against predicted biomass in the tropical dry forest of CCBR, while some polynomial models successfully predicted the observed biomass for the tropical wet forest of MABR. Factors such as Pleistocene extinctions and the absence of large, native grazers (i.e. Bovidae) that have kept ungulate richness and standing biomass relatively low in neotropical forests should be accounted for when comparing data sets from different regions
Female asynchrony may drive disruptive sexual selection on male mating phenotypes in a Heliconius butterfly
Get PDFAlternative male phenotypes may be a source of novel adaptive traits and may evolve under strong sexual selection. We studied interpopulation differences in male mating behavior related to receptive female synchrony in the monandrous pupal-mating butterfly Heliconius charitonia. In the population in which female-receptive pupae were more synchronous, larger males were unable to monopolize mates; variance in male mating success was lower; strength of sexual selection was weak; and all males competed for access to female pupae using the same strategy (pupal mating). In the population where no more than one female was receptive at a time (extreme asynchrony), only large males competed for pupae, and among these, only the largest individ- uals successfully mated. Thus, variance in mating success was higher, and sexual selection within pupal maters was stronger. In this population, smaller males patrolled large areas as an alternative mating behavior. When unmated females were experimen- tally released, small male size was associated with higher mating success. We suggest that alternative patrolling behavior may have evolved under strong sexual selection as a consequence of high asynchrony in receptive female availability in some populations
Lactarius fumosibrunneus in a relict Fagus grandifolia var. mexicana population in a Mexican montane cloud forest
Get PDFHow to measure the urban-wildland ecotone: Redefining ´peri-urban´ areas
Get PDFThe array of definitions regarding ?peri-urban? areas do not allow the precise measurement of its boundaries in a city. In this study, I developed an easy- to-use method to calculate the area where urban and adjacent non-urban systems intermingle. To validate that such areas were ecologically meaningful, I com- pared bird community species-richness, abundance, and composition from ?intra-? and ?peri-urban? areas in a medium-sized neotropical city. Results show that ?peri- urban? areas represent an important ecological interaction area for birds, and differ greatly from ?intra-urban? areas. The proposed method is robust and useful for a great variety of amoeboid-growing cities
FLORA DEL CENTRO DEL ESTADO DE CHIHUAHUA, MÉXICO
Get PDFSe estudió la flora de las serranías y planicies de la porción central del estado de Chihuahua. Se realizaron 135 salidas de campo en un periodo de seis años, en los que se colectaron aproximadamente 6500 ejemplares botánicos, se recopiló la información bibliográfica sobre el tema y se revisó el material botánico de la región de estudio depositado en los herbarios ANSM, CFNL y TEX-LL. Se registró un total de 112 familias, 493 géneros, 1322 especies y 232 categorías infraespecíficas de plantas vasculares. Del total de familias, 87 corresponden a dicotiledóneas, 15 a monocotiledóneas, 7 a helechos y afines, y 3 a coníferas y afines. Las familias con mayor número de géneros y especies respectivamente son: Asteraceae (86, 235), Poaceae (50, 163), Leguminosae (45, 137), Brassicaceae (16, 25), Malvaceae (12, 29), Scrophulariaceae (11, 29), Cactaceae (10, 30), Verbenaceae (10, 24), Nyctaginaceae (7, 21) y Amaranthaceae (7, 18). Los géneros con mayor número de especies son Muhlenbergia (37), Dalea (22), Euphorbia (21), Cheilanthes (19), Brickellia (17), Salvia (15), Cyperus (14), Quercus (13), Solanum (12), Eragrostis (12), Bouteloua (12), Erigeron (12), Astragalus (11), Ipomoea (11), Plantago (10), Acacia (10), Machaeranthera (9), Stevia (9), Opuntia (9), Aristida (9), Asclepias (9), Phaseolus (9), Oenothera (9), Viguiera (9) y Notholaena (9). El presente estudio es una contribución hacia un mejor conocimiento de la diversidad vegetal que existe en las regiones áridas del norte de México
SIMSIA BICENTENARIALIS (COMPOSITAE-HELIANTHEAE) UNA ESPECIE NUEVA DEL CENTRO DE MÉXICO
Get PDFSe describe como nueva y se ilustra Simsia bicentenarialis del noreste y centro de Querétaro y noreste de Guanajuato. La planta presenta semejanzas con algunas variedades de S. foetida (Cav.) S. F. Blake
