Some invasive plant species appear to strongly suppress neighbors in their nonnative ranges but much less so in their native range. We found that in the field in its native range in Mexico, the presence of Ageratina adenophora, an aggressive Neotropical invader, was correlated with higher plant species richness than found in surrounding plant communities where this species was absent, suggesting facilitation. However, in two nonnative ranges, China and India, A. adenophora canopies were correlated with much lower species richness than the surrounding communities, suggesting inhibition. Volatile organic compound (VOC) signals may contribute to this striking biogeographical difference and the invasive success of A. adenophora. In controlled experiments volatiles from A. adenophora litter caused higher mortality of species native to India and China, but not of species native to Mexico. The effects of A. adenophora VOCs on seedling germination and growth did not differ between species from the native range and species from the nonnative ranges of the invader. Litter from A. adenophora plants from nonnative populations also produced VOCs that differed quantitatively in the concentrations of some chemicals than litter from native populations, but there were no chemicals unique to one region. Biogeographic differences in the concentrations of some volatile compounds between ranges suggest that A. adenophora may be experiencing selection on biochemical composition in its nonnative ranges.

ResumenLas anormalidades pigmentarias en aves han adquirido mayor importancia e interés entre la comunidad ornitológica; sin embargo, resulta necesario contar con una herramienta de diagnóstico apropiada que brinde los criterios para lograr un sistema de identificación entre los distintos tipos de anormalidades. Para ello, proponemos una clave dicotómica para su identificación en campo con base en terminología obtenida de literatura especializada y una asociación de caracteres fenotípicos de aves. También, reportamos la presencia de anormalidades pigmentarias en la coloración corporal y de plumaje de cinco especies de aves que han sido observadas de forma ocasional en áreas perturbadas por impacto antropogénico en Tamaulipas, México: melanismo en la tortolita mexicana (Columbina inca), aberración ino en la paloma turca (Streptopelia decaocto), aberración ino en el correcaminos norteño (Geococcyx californianus), leucismo parcial en el pijuy (Crotophaga sulcirostris) y leucismo parcial en el tordo de ojo rojo (Molothrus aeneus). Las evidencias de casos actuales sugieren un aparente aumento de especies en vida libre con variación en la pigmentación. Las causas que lo provocan aún son discutibles, por lo cual, relacionar qué factores naturales o artificiales están involucrados en estos padecimientos podrá contribuir a determinar su origen y detectar problemas a nivel de poblaciones. La clave dicotómica propuesta en la identificación de anormalidades pigmentarias puede ser una herramienta continua en contextos modernos, si se unifica la terminología empleada.Palabras clave: Aberraciones cromáticas, coloración atípica, melanina, carotenos, leucismo, albinismo. AbstractColor abnormalities in birds have been receiving increasing attention within the ornithological community. However, it is important to create an appropriate tool to provide criteria to allow the accurate identification of the different types of abnormalities. Towards this end we have developed a dichotomous key for field identification of common abnormalities based on the termino logy on the scientific literature and visible phenotypic characteristics of the birds. In addition, we report on color abnormalities in the body and plumage of five species of birds observed in anthropogenically disturbed areas in Tamaulipas, Mexico: melanism in the Inca Dove (Columbina inca), ino in the Eurasian Collared Dove (Streptopelia decaocto), ino in the Greater Roadrunner (Geococcyx californianus), leucism in the Groove-billed Ani (Crotophaga sulcirostris), and partial leucism in the Bronzed Cowbird (Molothrus aeneus). Evidence of current cases suggest a significant increase in free-living species with variation in pigmentation. The causes that trigger it are still disputable, therefore, to relate which natural or man-made factors are involved in these conditions will help determine its origin and to detect problems on a population level. This dichotomous key proposed for the identification of abnormalities in pigmentation can be a continuous tool in modern research, st...

Loss of vegetation cover is a major factor that endangers biodiversity. Therefore, the use of geographic information systems and the analysis of satellite images are important for monitoring these changes in Natural Protected Areas (NPAs). In northeastern Mexico, the Natural Protected Area Altas Cumbres (NPAAC) represents a relevant floristic and faunistic patch on which the impact of loss of vegetation cover has not been assessed. This work aimed to analyze changes of land use and coverage (LULCC) over the last 42 years on the interior and around the exterior of the area, and also to propose the time of succession for the most important types of vegetation. For the analysis, LANDSAT satellite images from 1973, 1986, 2000, 2005 and 2015 were used, they were classified in seven categories through a segmentation and maximum likelihood analysis. A cross-tabulation analysis was performed to determine the succession gradient. Towards the interior of the area, a significant reduction of tropical vegetation and, to a lesser extent, temperate forests was found, as well as an increase in scrub cover from 1973 to 2015. In addition, urban and vegetation-free areas, as well as modified vegetation, increased to the exterior. Towards the interior of the NPA, the processes of perturbation and recovery were mostly not linear, while in the exterior adjacent area, the presence of secondary vegetation with distinct definite time of succession was evident. The analysis carried out is the first contribution that evaluates LULCC in this important NPA of northeastern Mexico. Results suggest the need to evaluate the effects of these modifications on species.

Los icneumónidos son avispas parasitoides de importancia en el control biológico de insectos plaga y constituyen una de las familias de Hymenoptera con mayor diversidad. El objetivo de esta investigación fue conocer la diversidad de Ichneumonidae y la relación con la temperatura ambiental y la precipitación pluvial en una localidad de Jaumave, Tamaulipas, México, durante un año. Se colocó una trampa Malaise a 1,450 m snm en una asociación de Pinus nelsonii, P. cembroides y Juniperus flaccida en una área seca, aunque con una pequeña corriente de agua cerca. Se recolectaron 1,115 icneumónidos, de los cuales la subfamilia Cryptinae fue la mejor representada en número de géneros y especies, siendo Pimpla el género más abundante y Pachysomoides stupidus la especie con más individuos. Se encontró una gran diversidad de ejemplares correspondientes a la familia estudiada. La temperatura presentó una correlación alta con la diversidad de Ichneumonidae, la precipitación pluvial una correlación moderada. Tres especies son nuevos registros para México y 5 especies para Tamaulipas, por lo que se conocen 1,298 especies de Ichneumonidae para el país. Este trabajo contribuye al conocimiento de Ichneumonidae en áreas secas de México. Derechos Reservados © 2015 Universidad Nacional Autónoma de México, Instituto de Biología. Este es un artículo de acceso abierto distribuido bajo los términos de la Licencia Creative Commons CC BY-NC-ND 4.0.

No abstract