Gray fox (Urocyon cinereoargenteus) parasite diversity in central Mexico.

Mexico has a long history of parasitological studies in communities of vertebrates. However, the mega diversity of the country makes fauna inventories an ongoing priority. Presently, there is little published on the parasite fauna of gray foxes (Urocyon cinereoargenteus Schereber, 1775) and this study provides new records of parasites for gray foxes in central Mexico. It is a continuation of a series of previous parasitological studies conducted with this carnivore in Mexico from 2003 to the present. A total of 24 foxes in the Parque Nacional El Cimatario (PANEC) were trapped, anaesthetized, and parasites recovered. The species found were Dirofilaria immitis, Ctenocephalides canis, C. felis, Euhoplopsillus glacialis affinis (first report for gray foxes in Mexico) Pulex simulants, and Ixodes sp. Three additional gray fox carcasses were necropsied and the parasites collected were adult nematodes Physaloptera praeputialis and Toxocara canis. The intensive study of the gray fox population selected for the 2013-2015 recent period allowed for a two-fold increase in the number of parasite species recorded for this carnivore since 2003 (nine to 18 parasite species), mainly recording parasitic arthropods, Dirofilaria immitis filariae and adult nematodes. The parasite species recorded are generalists that can survive in anthropic environments; which is characteristic of the present ecological scenario in central Mexico. The close proximity of the PANEC to the city of Santiago de Queretaro suggests possible parasite transmission between the foxes and domestic and feral dogs. Furthermore, packs of feral dogs in the PANEC might have altered habitat use by foxes, with possible impacts on transmission.

[Effects of environmental factors over aquatic hemimetabola and Coleoptera diversity in the Xichu's basin, Guanajuato, México]. / Efecto de los factores ambientales sobre la diversidad de insectos hemimetábolos y coleópteros acuáticos en la cuenca del Rio Xichú, Guanajuato, México.

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.

Efecto de los factores ambientales sobre la diversidad de insectos hemimetábolos y coleópteros acuáticos en la cuenca del Río Xichú, Guanajuato, México / Effects of environmental factors over aquatic hemimetabola and Coleoptera diversity in the Xichu’s basin, Guanajuato, México

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.

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.

Integridad biótica de la microcuenca del Río Chiquito, Morelia, Michoacán, México, basada en la comunidad de macroinvertebrados acuáticos

Biotic integrity of the Chiquito River subwatershed, Morelia, Michoacán México, based on the aquatic macroinvertebrate assemblages. The Chiquito River subwatershed supplies 30% of the potable water consumed by the city of Morelia, Michoacan, Mexico. It is necessary to constantly monitor its waters using metrics that evaluate environmental degradation and aquatic assemblages. In the present study, we used the Index of Biotic Integrity for Aquatic Macroinvertebrate Associations (IBIAMA), the Visual-Based Habitat Assessment, and the Most Probable State to calculate the conservation status of the river at six sites along the main channel, including an upper site as a reference. A total of 51 474 specimens were identified, the taxonomic composition was comprised of 69 families distributed into four Phyla, eight classes, eight sub-classes, and 18 orders. The best preserved sites were found in the subwatershed headwater zone. The intermediate zone had impacted hydraulic conditions, environmental quality and biotic integrity. The downstream part of the subwatershed showed the resilient capacity of the river to reestablish macroinvertebrate assemblages and environmental parameters. There is a strong correlation among environmental qualities and the IIBAMA. The use of macroinvertebrates in combination with environmental parameters showed that the Chiquito River subwatershed is stable, rich and integral in aquatic macroinvertebrate assemblages before entering the city of Morelia, and it conserves the processes that regulate the functional dynamics of the subwatershed. Rev. Biol. Trop. 62 (Suppl. 2): 221-231. Epub 2014 April 01.

La microcuenca del Río Chiquito abastece el 30% de agua potable para la ciudad de Morelia, Michoacán, México. Por ello es necesario el monitoreo constante de sus aguas, utilizando mediciones que evalúen el deterioro ambiental y la comunidad de macroinvertebrados acuáticos. Para el presente estudio se utilizó el Índice de Integridad Biótica para las Asociaciones de Macroinvertebrados Acuáticos (IIBAMA). Además de la Valoración de la Calidad Ambiental Visual y el estado más probable del cauce, en seis sitios dentro de la microcuenca y un séptimo fuera de la misma, como referencia. Se identificaron un total de 51 474 organismos: 69 familias distribuidas en cuatro filos, ocho clases, ocho subclases, y 18 órdenes. Los sitios mejor conservados se encuentran en la cabecera de la microcuenca. La zona intermedia se encuentra afectada en la condición hidráulica, calidad ambiental y en su integridad biótica. En la zona baja de la microcuenca, se observó la capacidad “resiliente” del río al restablecerse las comunidades de macroinvertebrados y los parámetros ambientales. Los resultados muestran que la calidad ambiental y el IIBAMA se encuentran correlacionados (r=0.82, p<0.01). El uso de los macroinvertebrados en combinación con los parámetros ambientales demuestran que antes de entrar a la ciudad de Morelia la microcuenca del río Chiquito es un sistema estable, diverso e íntegro en su comunidad de macroinvertebrados acuáticos, y que conserva los procesos que regulan la dinámica funcional de la cuenca.

Nematodes parasites of the gray fox (Urocyon cinereoargenteus Schreber, 1775) in the seasonally dry tropical highlands of central Mexico.

The gray fox (Urocyon cinereoargenteus Schreber, 1775) is the most abundant and opportunistic wild canid in Mexico. However, the parasites of this canid in Mexico are poorly known, and an intensive parasite survey is lacking. A survey of gray fox parasitological feces was conducted in El Cimatario National Park, a protected area representative of the seasonally dry, tropical highlands of Mexico. Feces were collected in six 1-km-length transects during the summer of 2003 and spring of 2004. The coproparasitoscopical survey registered nine species of nematodes, typical of wild and domestic canids such as Strongyloides stercoralis, Uncinaria stenocephala, Toxocara canis, Toxascaris leonina, Dioctophyme renale, Trichuris vulpis, Trichuris sp., and Capillaria sp. Ecological factors such as temperature and humidity appear to play a more important role in the establishment of these species of parasites in this protected area than the presence of domestic dogs.