RESUMO
The dietary niche breadth of the Burrowing Owl was determined (Athene cunicularia Molina, 1782) in Llano La Soledad, Galeana, Nuevo Leon in northern Mexico, by considering prey type, numerical percentage, weight, weight percentage, frequency of occurrence percentage, and IRI percentage. The study compared data from three winters (2002-2003, 2003-2004, 2004-2005) by analyzing 358 pellets, identifying 850 prey items. Invertebrates constituted 90% of prey items, which mostly included insects (85%); beetles were the most common insects found in pellets (70%). Vertebrates made up 84% of consumed weight, of which 83% were mammals. Most of the mammals were cricetid rodents (41%). Niche breadth based on the numerical and weight percentage confirmed the Burrowing Owl as a generalist species with mean values per year ranging between 0.65 and 0.82. Additionally, there was a strong association between the weight of rodent species in winter. This association was mainly driven by changes in composition and frequency of these prey species during the second winter, probably caused by high annual rainfall. The second season also showed a statistically significant narrower niche (Ro = 0.96) and the smallest overlap (0.45 vs. 0.76) among the three winters.
Assuntos
Estrigiformes , Animais , México , Estações do Ano , Dieta , MamíferosRESUMO
Knowledge gaps exist in the socio-ecological systems of small touristic islands in Latin America. Understanding tourists' perceptions of their environmental knowledge can help plan actions to prevent natural capital loss necessary for local economies. Tourists' perceptions of a touristic hotspot, Holbox Island, were documented. Surveys demonstrated that tourists are aware of their environmental impacts and are interested in minimizing these. Results were compared with results on Bocas del Toro, Panama. Tourists' perceptions had similarities among sites driven by similarities in tourists' populations with a common geographic origin. Tourists lack site-specific knowledge to steer them towards environmentally conscious decisions in both regions. Findings suggest the need to promote local actions to gain tourists' understanding about their destination and support education programs on island conservation. Addressing these needs can help build resilience to overcome the adverse socio-environmental effects of tourism, environmental disasters, and health crises as COVID-19 on small islands.
Assuntos
Meio Ambiente , Percepção , Turismo , COVID-19/epidemiologia , COVID-19/virologia , Humanos , Conhecimento , SARS-CoV-2/isolamento & purificação , Inquéritos e Questionários , Índias OcidentaisRESUMO
Heavy metals exposure has been linked to severe health problems. In Mexico, the Monterrey metropolitan area (MMA) is considered one of the most polluted industrial regions. Because birds have been used successfully as environmental biomonitors, the levels of lead, cadmium, and arsenic in feathers of Great-tailed grackles (Quiscalus mexicanus) from two sites within and one site outside the MMA were determined. One hundred birds were captured, samples were analyzed by atomic absorption spectrometry. Ciudad Universitaria had the highest mean values of lead and cadmium, 11.91 ppm d.w. and 1.66 ppm d.w., respectively. This was at least, 10- and 8-times higher than the two other sample sites. We believe that using Great-tailed grackles as bioindicators in conjunction with air pollutants sampling from meteorological stations in Monterrey City could help in making decisions when applying environmental remediation measures as well as in the selection of places for housing, school and work among others.
Assuntos
Monitoramento Ambiental , Metais Pesados , Animais , Cidades , Poluição Ambiental , Metais Pesados/análise , MéxicoRESUMO
BACKGROUND: The western burrowing owl (Athene cunicularia hypugaea) occurs throughout western North America in various habitats such as desert, short-grass prairie and shrub-steppe, among others, where the main threat for this species is habitat loss. Range-wide declines have prompted a need for reliable estimates of its populations in Mexico, where the size of resident and migratory populations remain unknown. RESULTS: Our objective was to estimate the abundance and density of breeding western burrowing owl populations in Mexican prairie dog (Cynomys mexicanus) colonies in two sites located within the Chihuahuan Desert ecoregion in the states of Nuevo Leon and San Luis Potosi, Mexico. Line transect surveys were conducted from February to April of 2010 and 2011. Fifty 60 ha transects were analyzed using distance sampling to estimate owl and Mexican prairie dog populations. We estimated a population of 2026 owls (95 % CI 1756-2336) in 2010 and 2015 owls (95 % CI 1573-2317) in 2011 across 50 Mexican prairie dog colonies (20,529 ha). CONCLUSIONS: The results represent the first systematic attempt to provide reliable evidence related to the size of the adult owl populations, within the largest and best preserved Mexican prairie dog colonies in Mexico.
Assuntos
Sciuridae/fisiologia , Estrigiformes/fisiologia , Animais , Ecossistema , México , Densidade Demográfica , Dinâmica PopulacionalRESUMO
Agricultural lands are exposed to pesticides continuously, which impact on habitat of wild species, such birds. The purpose of this study was to determine the plasma cholinesterase activity in two passeriform wild birds, the house finch (Carpodacus mexicanus) and the house sparrow (Passer domesticus), from agricultural land with exposure to pesticides. No significant difference was found in the house finch between specimens captured in non-agricultural and agricultural lands. However, house sparrows had significant differences in plasma cholinesterase activity, which indicates that this species is more sensitive to enzymatic activity inhibition by pesticides, and they could be indicators of pesticide pollution in agricultural areas.
Assuntos
Colinesterases/sangue , Exposição Ambiental , Poluentes Ambientais/toxicidade , Tentilhões/metabolismo , Praguicidas/toxicidade , Pardais/metabolismo , Agricultura , Animais , Colorimetria , Monitoramento Ambiental , Feminino , Masculino , MéxicoRESUMO
The Worthen's Sparrow (Spizella wortheni) is an endemic bird species of the Mexican Plateau that is protected by Mexican law. Considering its limited range (25 km(2)), small population size (100-120 individuals), and declining population, it is one of the most endangered avian species in North America. Although it has been assumed to be the sister taxon of the Field Sparrow (Spizella pusilla), the systematic and evolutionary relationships of Worthen's Sparrow have never been tested using modern molecular phylogenetic methods. We addressed the molecular phylogeny of S. wortheni analyzing six mitochondrial genes (3571 bp) from all of the natural members of the genus Spizella. Our maximum likelihood and Bayeasian analysis indicate that despite the superficial similarity, S. wortheni is not the sister taxon of S. pusilla, but is instead most closely related to the Brewer's Sparrow (Spizella breweri). Also new insights about the phylogenetics relationships of the Spizella genera are presented.
Assuntos
Filogenia , Pardais/genética , Animais , Teorema de Bayes , DNA Mitocondrial/genética , Espécies em Perigo de Extinção , Evolução Molecular , Funções Verossimilhança , México , Análise de Sequência de DNA , Pardais/classificaçãoRESUMO
West Nile virus has been isolated for the first time in Mexico, from a sick person and from mosquitoes (Culex quinquefasciatus). Partial sequencing and analysis of the 2 isolates indicate that they are genetically similar to other recent isolates from northern Mexico and the western United States.
Assuntos
Culex/virologia , RNA Viral/genética , Vírus do Nilo Ocidental/isolamento & purificação , Animais , Feminino , Humanos , México , Pessoa de Meia-Idade , Filogenia , Texas , Vírus do Nilo Ocidental/genéticaRESUMO
West Nile virus RNA was detected in brain tissue from a horse that died in June 2003 in Nuevo Leon State, Mexico. Nucleotide sequencing and phylogenetic analysis of the premembrane and envelope genes showed that the virus was most closely related to West Nile virus isolates collected in Texas in 2002.