Alimentación de los caprélidos (Crustacea: Amphipoda) de la costa oeste de Méjico. ¿Se alimentan de los sustratos en los que viven?

We studied the gut contents of the dominant species of the West coast of Mexico to explore if caprellids can use their host substrates (mainly hydroids and gorgonians) as food resource or just as a place to cling on. Two hundred and forty two specimens of four species of caprellids were examined: Aciconula acanthosoma Chess, 1989, Caprella equilibra Say, 1818, Caprella aff. penantis Leach, 1814 and Paracaprella sp. Detritus was the dominant component in all the species, although hydroids were also abundant in C. equilibra and Paracaprella sp. Crustaceans were present in the digestive tracts of the four species, being an important component in Aciconula acanthosoma and Paracaprella sp. Caprella aff. penantis and C. equilibra collected from gorgonians did not show any trace of gorgonian sclerites in their guts. Therefore, the present study reveals that caprellids from the Pacific coast of Mexico are able to feed on hydroids but not on gorgonians. Furthermore, Paracaprella sp. associated to hydroids also showed a significant amount of harpacticoid copepods in the digestive tract, supporting the idea of cleptocomensalism. Further experimental studies are needed to explore the complex relationships between hydroids and caprellids.Se estudió el contenido del digestivo de las especies dominantes de la costa oeste de Méjico para explorar si los caprélidos pueden usar los sustratos en los que viven (principalmente hidrozoos y gorgonias) como fuente de alimento o solamente como sustrato al que anclarse. Se examinaron doscientos cuarenta y dos ejemplares de cuatro especies de caprélidos: Aciconula acanthosoma Chess, 1989, Caprella equilibra Say, 1818, Caprella aff. penantis Leach, 1814 y Paracaprella sp. El componente dominante en todas las especies fue el detritus, aunque los hidrozoos también fueron abundantes en C. equilibra y Paracaprella sp. Se encontraron restos de crustáceos en los tractos digestivos de las cuatro especies, siendo un componente importante en Aciconula acanthosoma y Paracaprella sp. Caprella aff. penantis y C. equilibra recolectadas en gorgonias no mostraron ningún resto de escleritos en sus digestivos. Por tanto, el presente estudio revela que los caprélidos de la costa pacífica de Méjico son capaces de alimentarse de hidrozoos pero no de gorgonias. Además, Paracaprella sp. asociada a hidrozoos también mostró una cantidad importante de copépodos harpacticoides en el tracto digestivo, lo que apoya la idea de cleptocomensalismo. Para el futuro, sería interesante desarrollar estudios experimentales para explorar las complejas relaciones entre hidrozoos y caprélidos

The invisible enemy : Understanding bird-window strikes through citizen science in a focal city

Bird-window collisions have been estimated to be among the most important sources of bird death. Despite increasing knowledge in Latin America, our understanding of this phenomenon is still incipient, with research performed in Mexico limited to a handful of studies. Here, we present the results of a citizen science effort focused on bird-window collisions at seven buildings in the university campus of the National School of Higher Studies (ENES) of the National Autonomous University of Mexico, located in the city of Leon (central Mexico). Our main goal was to describe seasonal patterns of bird-window collisions and their relationship with building traits (i.e., building height, window area) through citizen science monitoring strategies. Our results showed that collisions were higher in two of the seven studied buildings, with two bird species recording almost half of the total collisions: Clay-colored Sparrow (Spizella pallida) and Indigo Bunting (Passerina cyanea). Seasonally, April was the only month to differ from the rest of the studied months, showing significantly higher rate of bird-window collision. Regarding building traits, only building height was related to the number of recorded bird-window collisions. In sum, our study provides findings from an understudied area, showing the value of citizen science approaches to generate knowledge on a deadly phenomenon. Notably, besides the potential drawbacks and importance of generating this kind of information, our project raised awareness on the topic across the entire campus community, from the students and academics to the administration, highlighting the potential for social impact with these kinds of projects.Peer reviewe

Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes

Copyright: © 2011 Mora et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas

Disease: A Hitherto Unexplored Constraint on the Spread of Dogs (Canis lupus familiaris) in Pre-Columbian South America

Although debate continues, there is agreement that dogs (Canis lupus familiaris) were first domesticated in Eurasia, spreading from there to other parts of the world. However, while that expansion already extended as far as Europe, China, and North America by the early Holocene, dogs spread into (and south of) the tropics only much later. In South America, for example, the earliest well attested instances of their presence do not reach back much beyond 3000 cal. BC, and dogs were still absent from large parts of the continent – Amazonia, the Gran Chaco, and much of the Southern Cone – at European contact. Previous explanations for these patterns have focused on cultural choice, the unsuitability of dogs for hunting certain kinds of tropical forest prey, and otherwise unspecified environmental hazards, while acknowledging that Neotropical lowland forests witness high rates of canine mortality. Building on previous work in Sub-Saharan Africa (Mitchell 2015) and noting that the dog’s closest relatives, the grey wolf (C. lupus) and the coyote (C. latrans), were likewise absent from South and most of Central America in Pre- Columbian times, this paper explores instead the possibility that infectious disease constrained the spread of dogs into Neotropical environments. Four diseases are considered, all likely to be native and/or endemic to South America: canine distemper, canine trypanosomiasis, canine rangeliosis, and canine visceral leishmaniasis caused by infection with Leishmania amazonensis and L. colombiensis. The paper concludes by suggesting ways in which the hypothesis that disease constrained the expansion of dogs into South America can be developed further

Éxito reproductivo de los pájaros bobos patas azul, Sula nebouxii, y los pájaros bobos café, Sula leucogaster, como indicador de perturbación por uso turístico en las Islas Marietas, México

Breeding success of the blue–footed booby, Sula nebouxii, and the brown booby, Sula leucogaster, as an indicator of touristic disturbance in the Islas Marietas, Mexico We studied the breeding success of two seabird species, the blue–footed booby, Sula nebouxii, and the brown booby, Sula leucogaster, in relation to touristic disturbance in order to focus conservation management strategies in the protected area of the Marietas Islands in Bahía de Banderas, Mexico. Data were collected throughout the breeding season of 2013 at Isla Larga. We considered three sites under different conditions of simulated disturbance within the colonies: ‘medium’, visits constrained to a single path; ‘high’, visits without spatial restrictions, and ‘low’, no visits. The total numbers of nests, eggs and chicks for each species were recorded weekly at the three sites. On the basis of these data, we determined the viability of eggs (hatching success) and chicks. A generalized linear mixed model (GLIMMIX) showed that breeding success (eggs–to–fledglings rate) had no relationship to the conditions of the area and but was significantly lower in the blue–footed booby. The presence of tourists, as measured in this study, was not the cause of nesting failure. Other, non–evaluated factors likely play a role in limiting the breeding success of the two species of booby studied here

Spatio-temporal discrepancies in lizard species and functional diversity

Conducting multi-faceted biodiversity assessments can provide a comprehensive vision of the organization of ecological communities over space and time. In this study, the spatio-temporal species diversity and α and β functional diversity of lizard assemblages were evaluated in four vegetation types over a two-season annual cycle. Additionally, site structural elements including vegetation, soil and environmental variables were characterized and related to the composition of lizard species. Both species diversity and functional diversity varied through space and time but followed different trends. Species diversity was higher in lowland vegetation types, characterized by greater tree canopy coverage (%) as well as higher temperature and humidity conditions, while species richness, evenness and functional divergence showed distinct trends. Similarly, seasonal differences were observed in species and functional diversity: the rainy season had greater species diversity, while func- tional diversity was higher during the dry season. Also, species β-diversity between vegetation types was characterized by turnover; while nestedness was the main component of functional β-diversity. Seasonally, there was no turnover in species or functional diversity. We conclude that vegetation type is the primary determinant of lizard diversity. However, the func- tional redundancy observed in lizard communities explains the opposite tendencies found between species and functional diversity at α and β levels