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1.
Rev Biol Trop ; 64(1): 221-33, 2016 03.
Artigo em Espanhol | MEDLINE | ID: mdl-28862421

RESUMO

The gray fox, Urocyon cinereoargenteus, is a medium-size canid widely distributed in México. Most studies on this species focus on habitat use, home range, diet, intraguild competence, and lanscape distribution between urban and rural sites. In central Veracruz, gray foxes are present in fragments of cloud forest and in shaded coffee plantations; nevertheless, its abundance has not yet been compared among other vegetation types found in the area, such as sugarcane plantations. In this study we described gray foxes abundance variations using 500 m transects, among sugarcane plantations, shaded coffee plantations, and cloud forest fragments throughout eight months, by scat counting in three sites of each cover type. We reported the relative abundance index for each cover type and each month, and evaluated its relationship with four landscape features: (a) shade percent, (b) trail density, (c) human population density, and (d) habitat juxtaposition, in influence areas of 450 ha around sampling sites. Abundance comparison among cover types showed lower abundances in cloud forest fragments and higher abundances in coffee and sugarcane plantations. No significant differences were found throughout months (p = 0.476). We proposed that higher abundances in plantations may be related to the presence of rodent plagues and fruit trees which offer food resources to gray foxes. The evaluation of landscape features showed that only medium-impact trail density and human population density were positively correlated with gray fox abundance; fact that demonstrates that this canid can coexist with humans in rural sites. We highlight the gray fox capacity to take advantage of heterogeneous landscapes.


Assuntos
Ecossistema , Raposas , Animais , Florestas , México , Densidade Demográfica
2.
Bull Environ Contam Toxicol ; 94(1): 17-22, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25304151

RESUMO

Amphibians are good models for monitoring contaminants in ecosystems because they transfer xenobiotic substances throughout trophic networks. We quantified bioaccumulated POCs by capturing and sacrificing ninety-one frogs (Charadrahyla taeniopus and Ecnomiohyla miotympanum) from four riverine forests immersed in agriculture and pasture lands in the La Antigua, Veracruz, Mexico watershed. The concentrations of ∑DDTs, ∑HCHs, ∑Endosulphans, ∑Heptachlors, ∑Drines, and ∑Chlordanes were measured by gas chromatography and compared between species, sites and seasons. In E. miotympanum the concentration of ∑HCHs was highest at 4,746.46 µg/g, while in C. taeniopus that of the ∑DDTs was highest at 2,637.10 µg/g. Concentrations of ∑Endosulphans, ∑HCHs, ∑Chlordanes and ∑Drines differed between the two species, and were always higher in E. miotympanum. In E. miotympanum the concentration of ∑Drines differed between sites, while for C. taeniopus ∑Heptachlors differed between seasons and ∑Drines among sites. These findings indicate that the two frog species even bioconcentrate POCs that are banned and may disrupt their reproduction. The effect however may vary according to the site and the frog species.


Assuntos
Anuros/metabolismo , Hidrocarbonetos Clorados/metabolismo , Praguicidas/metabolismo , Poluentes Químicos da Água/metabolismo , Agricultura , Animais , Anuros/anatomia & histologia , Tamanho Corporal , Cromatografia Gasosa , Monitoramento Ambiental , Hidrocarbonetos Clorados/análise , México , Praguicidas/análise , Poluentes Químicos da Água/análise
3.
Sci Rep ; 14(1): 25084, 2024 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-39443561

RESUMO

Even though the use of organochlorine pesticides has been prohibited since the last century their presence is still being recorded around the world. In the upper La Antigua watershed, Veracruz, Mexico we have reported concentrations of these contaminants in different compartments of the riverine ecosystems. This is of relevance due to their potential disruptive endocrine effect on the vertebrates drinking the water or feeding in the riverine area. In this study we evaluated concentrations of organochlorine pesticides (OCPs) in streams running throughout mountain cloud forest and two different types of land use, pasture lands and coffee plantations. Water and periphyton samples were collected during the wet and the dry seasons from streams located in independent micro-basins. Spatial explicit analyzes show that the concentrations measured are independent of the distribution of the streams in the geographical area sampled. However seasonal differences were found during the dry season in the water and during the rainy season in periphyton. While OCPs in water support the idea that micro-basins can be used as independent monitoring units, OCPs in periphyton can be indicators of the effect of different land use. Some concentrations of all the OCPs registered had values above the limits for tap water.


Assuntos
Monitoramento Ambiental , Hidrocarbonetos Clorados , Praguicidas , Estações do Ano , Poluentes Químicos da Água , México , Hidrocarbonetos Clorados/análise , Praguicidas/análise , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Análise Espaço-Temporal , Rios/química , Ecossistema
4.
Environ Monit Assess ; 185(2): 1163-73, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22527458

RESUMO

Top predators like the Neotropical otter, Lontra longicaudis annectens, are usually considered good bioindicators of habitat quality. In this study, we evaluated heavy metal contamination (Hg(tot), Pb, Cd) in the riverine habitat, prey (crustaceans and fish), and otter feces in two Ramsar wetlands with contrasting upstream contamination discharges: Río Blanco and Río Caño Grande in Veracruz, Mexico, during the dry, the wet, and the nortes seasons. Most comparisons revealed no differences between sites while seasonal differences were repeatedly detected for all of the compartments. Higher concentrations of Pb during the dry season and of Cd during the wet season in otter feces mirrored differences detected in the most seasonally consumed prey. Compared with fecal methylmercury values reported for the European otter (0.25-0.75 mg kg(-1)) in unprotected areas, the Hg(tot) levels that we measured were lower (0.02-0.17 mg kg(-1)). However, Pb (117.87 mg kg(-1)) and Cd (9.14 mg kg(-1)) concentrations were higher (Pb, 38.15 mg kg(-1) and Cd, 4.72 mg kg(-1)) in the two Ramsar wetlands. Protected areas may shelter species, but those with water-linked diets may suffer the effect of chemicals used upstream.


Assuntos
Monitoramento Ambiental , Cadeia Alimentar , Metais Pesados/análise , Lontras/fisiologia , Poluentes Químicos da Água/análise , Áreas Alagadas , Animais , Crustáceos/metabolismo , Fezes/química , Feminino , Peixes/metabolismo , Contaminação de Alimentos , Masculino
5.
PLoS One ; 18(12): e0295738, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38100504

RESUMO

The relative importance of allochthonous and autochthonous carbon (C) as sources of energy for tropical stream food webs remains an open question. Allochthonous C might be the main energy source for small and shaded forest streams, while autochthonous C is more likely to fuel food webs draining land uses with less dense vegetation. We studied food webs in cloud forest streams draining watersheds with forests, coffee plantations, and pastures. Our goal was to assess the effects of those land uses on the C source and structure of stream food webs. The study took place in tropical montane streams in La Antigua Watershed, in eastern Mexico. We selected three streams per land use and sampled biofilm and leaf litter as the main food resources, and macroinvertebrates and aquatic vertebrates from different trophic guilds. Samples were analyzed for δ13C and δ15N isotopes. Using a Bayesian mixing model, we estimated the proportional assimilation of autochthonous and allochthonous carbon by each guild. We found that consumers were mostly using allochthonous C in all streams, regardless of watershed land use. Our findings indicate that montane cloud forest streams are dominated by allochthony even in watersheds dominated by pastures. Abundant precipitation in this life zone might facilitate the movement of allochthonous C into streams. While food webs of streams from coffee plantations and pastures also rely on allochthonous resources, other impacts do result in important changes in stream functioning.


Assuntos
Carbono , Cadeia Alimentar , Animais , Teorema de Bayes , Florestas , Biofilmes , Ecossistema
6.
Arch Environ Contam Toxicol ; 62(3): 445-54, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22002785

RESUMO

Effects of endocrine disruptors on reproductive variables of top predators, such as alligators and crocodiles, have long been cited. Due to their long life span, these predators provide us with historic contaminant annals. In this study we tried to test whether lifestyle (free-ranging vs. farm animals) and reproductive age of Morelet's crocodiles in Campeche, Mexico, affect the bioaccumulation of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). Subsequently, we tested to see whether their concentration was related to steroid hormones (testosterone and estradiol-17ß) levels once normal cyclic hormone variation and reproductive age had been taken into account. From the group of contaminants considered (analyzed as families), only frequency of hexachlorocyclohexanes (∑HCH) and ∑PCB permitted analyses. Whereas there was a greater concentration of ∑HCH bioaccumulated by free-ranging crocodiles, ∑PCB was found in equal quantities in free-ranging and farm animals. No difference was observed in relation to reproductive age for any of the contaminants. However, ∑PCB concentrations were related to testosterone levels among female crocodiles. This androgenic effect of ∑PCB has not been reported previously. Because testosterone promotes aggressive behavior in vertebrates, excessive aggression during the estrous season, or when female crocodiles should be caring for their young, could result in reproductive failure in Morelet's crocodiles and potential long-term decline of the population.


Assuntos
Jacarés e Crocodilos/metabolismo , Hormônios Esteroides Gonadais/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Disruptores Endócrinos/metabolismo , Disruptores Endócrinos/toxicidade , Monitoramento Ambiental , Feminino , Hidrocarbonetos Clorados/metabolismo , Hidrocarbonetos Clorados/toxicidade , Masculino , México , Praguicidas/metabolismo , Praguicidas/toxicidade , Bifenilos Policlorados/metabolismo , Bifenilos Policlorados/toxicidade , Poluentes Químicos da Água/toxicidade , Poluição Química da Água/estatística & dados numéricos
7.
Am J Primatol ; 72(6): 539-48, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20135692

RESUMO

In recent years populations of howler monkeys (Alouatta palliata) in southeastern Mexico have decreased substantially due to the transformation and loss of natural habitats. This is especially evident in the Santa Marta mountain range, Veracruz, Mexico where several studies have evaluated the impact of fragmentation on howler monkey populations in order to propose management programs for their conservation. The conditions generated by fragmentation likely change the rates of parasitic infection and could decrease howler survival. In this study, gastrointestinal parasite species richness, prevalence, and egg density of infection were determined in howler groups inhabiting five forest fragments at the Santa Marta mountain range. Two hundred and seventy-eight fresh fecal samples were collected between October 2002 and April 2003. Three parasite species were found during the dry and the wet season in all forest fragments sampled: one unidentified species of Eimeriidae; Trypanoxyuris minutus (Oxyuridae); and Controrchis biliophilus (Dicrocoeliidae). Both the prevalence of T. minutus and infection density for all parasites differed between seasons and fragments (the largest fragment consistently differed from other fragments). Host density, distance to the nearest town, fragment size, fragment shape, and total basal area of food trees explained parasite prevalence, but each species had a different pattern. Although parasite richness was lower, prevalence and density were higher than values reported for howlers in conserved forests. These results suggest that the establishment of biological corridors and animal translocation programs must take into account the parasite ecology of each fragment to avoid higher infection rates and preclude potential consequent mortality.


Assuntos
Alouatta/parasitologia , Eimeriida/isolamento & purificação , Trato Gastrointestinal/parasitologia , Helmintos/isolamento & purificação , Doenças Parasitárias em Animais/classificação , Animais , Bases de Dados Factuais , Dicrocoeliidae/classificação , Dicrocoeliidae/isolamento & purificação , Ecossistema , Eimeriida/classificação , Espécies em Perigo de Extinção , Fezes/parasitologia , Helmintos/classificação , Oxyurida/classificação , Oxyurida/isolamento & purificação , Doenças Parasitárias em Animais/prevenção & controle
8.
Physiol Biochem Zool ; 80(6): 580-91, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17909995

RESUMO

Physiological strategies that maximize reproductive success may be phylogenetically constrained or might have a plastic response to different environmental conditions. Among mammals, Canidae lend themselves to the study of these two influences on reproductive physiology because all the species studied to date have been characterized as monestrous (i.e., a single ovulatory event per breeding season), suggesting a phylogenetic effect. Greater flexibility could be associated with environments that are less seasonal, such as the tropics; however, little is known for many of the species from this region. To compensate for this lack of data, two regressions were done on the length of the reproductive season relative to the latitudinal distribution of a species: one with raw data and another with phylogenetically independent contrasts. There was a significant negative relationship, independent of phylogeny, with canids that have longer breeding seasons occurring at lower latitudes. In contrast, the pervasiveness of monestrus within Canidae appears to be phylogenetically constrained by their pairing/packing life and is most likely associated with monogamy. The persistence of the monestrous condition is supported by a captive study where a tropical canid, the fennec fox, Vulpes zerda, never exhibited polyestrous cycles despite a constant photoperiod (12L : 12D).


Assuntos
Adaptação Fisiológica/fisiologia , Canidae/fisiologia , Reprodução/fisiologia , Animais , Cruzamento , Canidae/genética , Demografia , Feminino , Fotoperíodo , Filogenia , Estações do Ano , Comportamento Sexual Animal
9.
Chemosphere ; 175: 373-382, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28236707

RESUMO

Riparian forests are recognized as important ecosystems for biodiversity conservation in transformed landscapes. Many animal species that use this type of vegetation facilitate its recovery through pollination and seed dispersal. In landscapes dominated by agrosystems and cattle ranching, persistent organochlorine pesticides (OCPs) in the riparian system may have an effect on the physiology and fitness of animals. In this study, we measured bioaccumulation of OCPs in the most abundant frugivorous bat, Sturnira hondurensis, from the upper part of La Antigua basin, Veracruz, Mexico and, from these data, estimated accumulation by the frugivorous bat community of riparian forests in contrasting, transformed (TL) and forested (FL) landscapes. Concentration of ΣDDT, Σdrines, Σclordano, ΣHCH, Σheptachlor and Σendosulfan was measured by gas-chromatography in 23 female and 33 male adult Sturnira captured during the dry and rainy seasons. Using censored data statistics, we found that the sex of the individual was significant for ΣHCH, and that interactions of landscape type (TL vs. FL) and season (dry vs. wet), and sex and season were significant for Σendosulfan and Σdrines, respectively. Mean ΣDDT (6.86 µg/g) and ΣHCH (28.22 µg/g) concentrations were lower than those reported for frugivorous bats in India but concentrations of Σdrines (13.86 µg/g) were higher than those reported in insectivorous bats. In our study sites, frugivorous bats are bioaccumulating higher amounts of OCPs in TL than in FL. We discuss the potential of this species as a bio-indicator of OCPs contamination in river basins.


Assuntos
Quirópteros/metabolismo , Monitoramento Ambiental/métodos , Florestas , Hidrocarbonetos Clorados/análise , Praguicidas/análise , Árvores/crescimento & desenvolvimento , Animais , Biodiversidade , Feminino , Hidrocarbonetos Clorados/metabolismo , Masculino , México , Praguicidas/metabolismo , Chuva , Estações do Ano , Sementes
10.
Mar Pollut Bull ; 91(1): 139-48, 2015 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-25549825

RESUMO

Organochlorine pesticides and PCB (POPs) concentrations were determined in the blood and eggs of green and hawksbill turtles. We compared concentrations between species, analyzed the relationship between turtle size and the POPs concentrations and the relationship between the concentrations in the blood of the nesting turtles and their eggs. We expected higher concentrations in the hawksbill turtle because of its higher trophic level, but concentrations were not higher in all the cases. Significant differences were found in δ-HCH blood concentrations. Lindane, heptachlor epoxide and PCB 101 concentrations were significantly higher in the hawksbill eggs. The relationship between the size of the turtles and the POP concentrations in the eggs of the hawksbills showed a negative correlation. No correlation was found between the size of the female and concentrations in the blood. In eggs, only the hawksbill turtles exhibited negative correlation in the concentration of mirex and PCB 44 and size.


Assuntos
Hidrocarbonetos Clorados/sangue , Exposição Materna , Óvulo/metabolismo , Praguicidas/sangue , Bifenilos Policlorados/sangue , Tartarugas/sangue , Animais , Feminino , Heptacloro Epóxido/metabolismo , Hexaclorocicloexano/sangue , Hexaclorocicloexano/metabolismo , Hidrocarbonetos Clorados/metabolismo , México , Praguicidas/metabolismo , Bifenilos Policlorados/metabolismo , Especificidade da Espécie , Estatísticas não Paramétricas , Tartarugas/metabolismo
11.
Zool Stud ; 54: e50, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-31966137

RESUMO

BACKGROUND: Studies of morphometric variation make it possible to delimit species and geographic intraspecific variation, mainly in species with wide distribution ranges. In the Neotropical otter, Lontra longicaudis, variation in the shape of the rhinarium of three potential subspecies has been described but it is not known whether there is a pattern to the morphometric variation in the skull throughout the distribution of this species. We analyzed morphological variation in the cranium (ventral view) and the mandible (lateral view) of the Neotropical otter, comparing male and female specimens and evaluating the differences between specified geographic units utilizing methods from geometric morphometrics. Specimens from the entire distribution of the species were analyzed. Between sexes, variability in the shape was determined by calculating the Procrustes distances and using Goodall's F test. Geographic variationwas analyzed using a discriminant analysis, an analysis of variance (ANOVA) on a matrix of partial warp scores, and a cluster analysis with Mahalanobis distances, allowing for similarities in shape to be identified between different geographic units. Variation in the size of the two structures was calculated based on the values for centroid size using a one-way ANOVA with a Bonferroni correction and a 95 % confidence interval. RESULTS: There was sexual dimorphism in shape for both views, with males the largest. In general, there was geographic variation in the shape and size of both the cranium and the mandible in the Neotropical otter, exhibiting a pattern that resembled Bergmann's rule. Variation in shape between geographic units could result from the presence of geographic barriers, the spatial configuration of hydrological regions, and/or the large distances between populations throughout this species' distribution. CONCLUSIONS: The Neotropical otter exhibits dimorphism in the size, but not in the shape of the skull. There is geographic variation between geographic units, and our results suggest that L.longicaudis could bea group of species. An integrative study using molecular and morphological data could elucidate its taxonomy.

12.
Rev. biol. trop ; Rev. biol. trop;64(1): 221-233, ene.-mar. 2016. tab, ilus
Artigo em Espanhol | LILACS | ID: biblio-843273

RESUMO

ResumenLa zorra gris (Urocyon cinereoargenteus Schreber) es un cánido de tamaño mediano que se distribuye ampliamente en México. La mayoría de los estudios sobre esta especie se han enfocado en el uso de hábitat, el ámbito hogareño, la dieta, la competencia con otros carnívoros y su distribución en diferentes paisajes tanto urbanos como rurales. Se tiene conocimiento de su presencia en fragmentos de bosque mesófilo de montaña y cafetales de sombra en el centro de Veracruz, aunque no se ha comparado su abundancia con otras coberturas vegetales como los cultivos presentes en la región. En este estudio describimos las variaciones de la abundancia mensual de zorra gris a través del registro de excretas en transectos de 500 m en cañaverales, cafetales de sombra y fragmentos de bosque mesófilo de montaña entre octubre del 2008 y mayo del 2009. Reportamos el índice de abundancia relativa para cada cobertura y cada mes, y evaluamos la relación de cuatro variables del paisaje (porcentaje de sombra, densidad de caminos, densidad de población humana y entremezcla de hábitats) en áreas de influencia de 450 ha alrededor de los sitios de muestreo. La comparación de la abundancia entre coberturas, mostró abundancias menores en los fragmentos de bosque mesófilo y mayores en los cafetales de sombra y cañaverales. No se encontró diferencia significativa a través de los meses (P= 0.476). Se plantea que la abundancia mayor en los cultivos puede estar asociada a las plagas de roedores y a la presencia de árboles frutales que ofrecen alimento a la zorra gris. De las variables del paisaje evaluadas solo la densidad de caminos de impacto medio y la densidad de población se correlacionaron positivamente con la abundancia de zorra gris, lo que demuestra que puede cohabitar con el humano sobre todo en zonas rurales. Se destaca la capacidad de la zorra gris para aprovechar los paisajes heterogéneos.


AbstractThe gray fox, Urocyon cinereoargenteus, is a medium-size canid widely distributed in México. Most studies on this species focus on habitat use, home range, diet, intraguild competence, and lanscape distribution between urban and rural sites. In central Veracruz, gray foxes are present in fragments of cloud forest and in shaded coffee plantations; nevertheless, its abundance has not yet been compared among other vegetation types found in the area, such as sugarcane plantations. In this study we described gray foxes abundance variations using 500 m transects, among sugarcane plantations, shaded coffee plantations, and cloud forest fragments throughout eight months, by scat counting in three sites of each cover type. We reported the relative abundance index for each cover type and each month, and evaluated its relationship with four landscape features: (a) shade percent, (b) trail density, (c) human population density, and (d) habitat juxtaposition, in influence areas of 450 ha around sampling sites. Abundance comparison among cover types showed lower abundances in cloud forest fragments and higher abundances in coffee and sugarcane plantations. No significant differences were found throughout months (p = 0.476). We proposed that higher abundances in plantations may be related to the presence of rodent plagues and fruit trees which offer food resources to gray foxes. The evaluation of landscape features showed that only medium-impact trail density and human population density were positively correlated with gray fox abundance; fact that demonstrates that this canid can coexist with humans in rural sites. We highlight the gray fox capacity to take advantage of heterogeneous landscapes.


Assuntos
Animais , Ecossistema , Raposas , Florestas , Densidade Demográfica , México
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