Southwestern Naturalist最新文献

{"title":"EFFECT OF UNDERLYING HYDROTHERMALLY ALTERED BEDROCK ON THE BENTHIC AND HYPORHEIC INVERTEBRATE COMMUNITY STRUCTURE IN CABRESTO CREEK, NEW MEXICO","authors":"G. D. De Jong","doi":"10.1894/0038-4909-66.4.290","DOIUrl":"https://doi.org/10.1894/0038-4909-66.4.290","url":null,"abstract":"Abstract The Red River watershed of Taos County, New Mexico, is underlaid in part by hydrothermally altered granitic bedrock, including stockwork veins of metal sulfide deposits. Erosion has exposed “scars” of this weathered, altered material along the watershed ridges above the mainstem Red River. Precipitation brings acid rock drainage (high sediment loads and toxic by-products of metal sulfide decomposition) into the Red River, negatively impacting the water quality, substrate, and aquatic community of the stream. A tributary to the Red River, Cabresto Creek, is also underlaid in part by hydrothermally altered granitic bedrock but has little erosion. I collected data on water quality, sediment, and the benthic and hyporheic invertebrate communities from 2005 to 2009 at sites along Cabresto Creek to assess the potential effect of the underlying geology in the absence of erosion. Statistically significant differences in both density and taxa richness existed among sites in both communities; however, values for density and taxa richness recovered to upstream levels at sites downstream of the zone of hydrothermal alteration in the hyporheic community, but only to a limited extent in the benthic community. Smaller sediment grain sizes and lower dissolved oxygen concentrations in the hyporheic within the zone of hydrothermal alteration may have restricted recruitment to the benthic community. These effects continued downstream, possibly due to drift. The results suggest that the underlying geology might affect the benthic and hyporheic invertebrate communities in Cabresto Creek even in the absence of eroded hydrothermal scars in the watershed. Resumen La cuenca hidrográfica del Red River de Nuevo México está subyacida en parte por la base de roca granítica alterada hidrotérmicamente, incluyendo las venas de depósitos de sulfuro metálico. La erosión ha expuesto “cicatrices” de este material desgastado y alterado a lo largo de las crestas de las cuencas hidrográficas sobre el cauce principal del Red River. La precipitación trae drenaje de roca ácida (altas cargas de sedimentos y subproductos tóxicos de la descomposición del sulfuro metálico) al Red River, lo que afecta negativamente la calidad del agua, el sustrato y la comunidad acuática del arroyo. Cabresto Creek, un afluente del Red River, también está subyacido en parte por la base de roca granítica alterada hidrotérmicamente, pero tiene poca erosión. Recopilé datos sobre la calidad del agua, los sedimentos, y las comunidades de invertebrados bentónicos e hiporréicos de 2005 a 2009 en sitios a lo largo de Cabresto Creek para evaluar el efecto potencial de la geología subyacente en ausencia de erosión. Hubo diferencias estadísticamente significativas en ambas densidad y riqueza de taxones entre los sitios de ambas comunidades; sin embargo, los valores de densidad y riqueza de taxones recuperaron a los de río arriba en sitios río abajo de la zona de alteración hidrotermal en la comunidad hiporréica,","PeriodicalId":51157,"journal":{"name":"Southwestern Naturalist","volume":"66 1","pages":"290 - 297"},"PeriodicalIF":0.2,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48966617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SMALL-SCALE VARIATION IN TRAP PLACEMENT AFFECTS ARTHROPOD CAPTURE RATES ON STICKY TRAPS IN RIPARIAN WOODLANDS","authors":"D. LaRoche, C. Conway, Chris Kirkpatrick","doi":"10.1894/0038-4909-66.4.275","DOIUrl":"https://doi.org/10.1894/0038-4909-66.4.275","url":null,"abstract":"Abstract Arthropods are important prey for many avian taxa, particularly during the breeding season. Many studies have used sticky traps to estimate relative abundance of arthropods as avian prey, but we know little about the potential biases associated with sticky traps. We evaluated the effect of small-scale variation in trap placement on the biomass of arthropods caught on sticky traps in six riparian woodlands in southeastern Arizona. We detected differences in arthropod biomass between two height categories (1 and 4 m off the ground) for three insect orders and between two sampling locations (0 and 10 m from the center of the stream bed) for two insect orders. These differences indicate that placement of sticky traps affects arthropod capture rates and, hence, small variation in trap placement can bias investigators' ability to document spatial and temporal differences in arthropod abundance. Investigators who use sticky traps to make comparisons of arthropod abundance need to ensure that placement is consistent over time or across treatments to ensure that comparisons are not biased. Resumen Los artrópodos son presas importantes para muchos taxones de aves, especialmente durante la temporada de reproducción. Muchos estudios han utilizado trampas adhesivas para estimar la abundancia relativa de artrópodos como presas aviares, pero sabemos poco sobre los posibles sesgos asociados con las trampas adhesivas. Evaluamos el efecto de la variación en la colocación de trampas a pequeña escala en la biomasa de artrópodos atrapados en trampas adhesivas en seis bosques ribereños en el sureste de Arizona. Detectamos diferencias en la biomasa de artrópodos entre dos categorías de altura (1 y 4 m del suelo) para tres órdenes de insectos y entre dos ubicaciones de muestreo (0 y 10 m del centro del lecho del arroyo) para dos órdenes de insectos. Estas diferencias indican que la ubicación de las trampas adhesivas afecta las tasas de captura de artrópodos y, por lo tanto, una pequeña variación en la ubicación de las trampas puede sesgar la capacidad de los investigadores para documentar las diferencias espaciales y temporales en la abundancia de artrópodos. Los investigadores que usan trampas adhesivas para hacer comparaciones de la abundancia de artrópodos deben asegurarse de que la ubicación sea consistente a lo largo del tiempo o entre tratamientos para garantizar que las comparaciones no estén sesgadas.","PeriodicalId":51157,"journal":{"name":"Southwestern Naturalist","volume":"66 1","pages":"275 - 279"},"PeriodicalIF":0.2,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44922226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ATTEMPTED PREDATION OF THE NUDIBRANCH PELTODORIS NOBILIS BY THE SEA ANEMONE ANTHOPLEURA ARTEMISIA","authors":"F. E. Hayes, Sh Schultz","doi":"10.1894/0038-4909-66.3.265","DOIUrl":"https://doi.org/10.1894/0038-4909-66.3.265","url":null,"abstract":"Abstract Sea anemones rarely prey upon nudibranch molluscs, which employ several effective defensive strategies. We documented a nudibranch, Peltodoris nobilis, partially engulfed by a sea anemone, Anthopleura artemisia, in situ in Northern California on 13 September 2020. It is unknown whether the sea anemone successfully consumed and digested the nudibranch. Previous natural and experimental observations reveal that most nudibranchs either escape from sea anemones or the sea anemones consume and then regurgitate the nudibranchs. Resumen Las anémonas de mar rara vez se alimentan de moluscos nudibranquios, que emplean varias estrategias defensivas efectivas. Documentamos un nudibranquio, Peltodoris nobilis, parcialmente engullido por una anémona de mar, Anthopleura artemisia, in situ en el norte de California el 13 de septiembre de 2020. Se desconoce si la anémona de mar consumió y digirió con éxito el nudibranquio. Observaciones naturales y experimentales anteriores revelan que la mayoría de los nudibranquios escapan de las anémonas de mar o las anémonas de mar consumen y luego regurgitan los nudibranquios.","PeriodicalId":51157,"journal":{"name":"Southwestern Naturalist","volume":"66 1","pages":"265 - 266"},"PeriodicalIF":0.2,"publicationDate":"2022-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48648387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LONG DISPERSAL DISTANCES OF THREE MALE BOBCATS IN TEXAS","authors":"Jennifer M. Korn, J. Ray, Lena M. Thurmond, M. E. Tewes, Raymond S. Matlack","doi":"10.1894/0038-4909-66.3.261","DOIUrl":"https://doi.org/10.1894/0038-4909-66.3.261","url":null,"abstract":"Abstract Dispersal distance of bobcats (Lynx rufus) can be affected by many factors: age and sex, bobcat density, prey abundance, and landscape permeability. Female offspring typically remain near their natal range, whereas males travel farther distances. Studies report dispersal distances between 10 and 85 km, with distances ≥80 km being rare. We report dispersal distances of two male bobcats in the Southern High Plains of Texas, and one male bobcat from the Rio Grande Plains of South Texas. The two male bobcats of Southern High Plains traveled 63 and 133 km and the male bobcat of Rio Grande Plains traveled 100 km. Severe droughts occurred in both regions during dispersal, which may have influenced distance traveled. In all cases, it is likely that nearby available territories were occupied by older resident bobcats, thus eliciting the need for longer-distanced dispersal to secure a permanent home range. Resumen La distancia de dispersión de gatos montés (Lynx rufus) puede ser afectada por muchos factores: la edad y el sexo, la abundancia de los gatos montés, la abundancia de presa y la permeabilidad del paisaje. Las crías hembras típicamente se quedan cerca de su rango de nacimiento, mientras que los machos viajan distancias más lejanas. Estudios han reportado distancias de dispersión entre 10 y 85 km, con distancias ≥ 80 km siendo raras. Reportamos distancias de dispersión de dos gatos montés machos en los Southern High Plains de Texas, y otro gato montés macho del Rio Grande Plains of South Texas. Los dos gatos montés machos de Southern High Plains viajaron 63 km y 133 km, y el otro gato montés macho de Rio Grande Plains viajó 100 km. Durante la dispersión hubo sequías severas en ambas regiones que pueden haber influido en la distancia recorrida. En todos los casos, es muy posible que territorios más cercanos estaban ocupados por otros gatos montés más viejos y residentes, suscitando la necesidad de viajar distancias más lejanas para asegurar un rango de hogar permanente.","PeriodicalId":51157,"journal":{"name":"Southwestern Naturalist","volume":"66 1","pages":"261 - 264"},"PeriodicalIF":0.2,"publicationDate":"2022-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41733152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"STUDIES OF MORPHOLOGICAL AND GENETIC VARIABILITY OF HERICIUM ERINACEUS FROM THE NORTHWEST AREA OF THE SIERRA MADRE OCCIDENTAL, DURANGO, MEXICO","authors":"Laura A. Páez-Olivan, M. Correa-Ramírez, L. Guzmán-Dávalos, Néstor Naranjo-Jiménez, N. Almaraz-Abarca, J. A. Ávila-Reyes, Jaime Herrera-Gamboa, Imelda Rosas Medina, L. S. González-Valdez, R. Torres-Ricario","doi":"10.1894/0038-4909-66.3.225","DOIUrl":"https://doi.org/10.1894/0038-4909-66.3.225","url":null,"abstract":"Abstract Hericium erinaceus, known as lion's mane, is one of the most important cultivated mushrooms worldwide. It grows wild through European and North American countries; meanwhile, in Asia it is mostly artificially cultivated. Several studies revealed the difficulty of its taxonomic identification and the influence of environmental conditions over its morphological characters. The present study aimed to evaluate the morphological and genetic variability of wild specimens of H. erinaceus collected from seven different sites in the temperate forests of the Sierra Madre Occidental, Durango, Mexico. The H. erinaceus isolates showed important morphological differences between the different specimens, mainly in the length of the basidioma, in some cases presenting as twice the size (55 cm) as that previously reported for the species. Unlike the morphological results, the genetic analysis showed homogeneity among the samples. Despite the obvious differences in morphological studies, the genetic study did not indicate a significant difference between the analyzed individuals. However, current results provide new information for the morphological characterization of specimens for northern Mexico, and the first record of seven new internal transcribed spacer sequences and geographic distribution data for this species in northern Mexico. Resumen Hericium erinaceus, conocido como melena de león, es uno de los hongos cultivados más importantes en el mundo. Se puede encontrar creciendo de manera silvestre en países de Europa y Norte América, mientras que en Asia se cultiva principalmente de manera artificial. Varios estudios revelaron la dificultad de su identificación taxonómica y la influencia de las condiciones ambientales sobre sus caracteres morfológicos. El presente estudio tuvo como objetivo evaluar la variabilidad morfológica y genética de especímenes silvestres de H. erinaceus recolectados en siete sitios diferentes de los bosques templados de la Sierra Madre Occidental, Durango, México. Las muestras de H. erinaceus mostraron diferencias morfológicas importantes entre los diferentes especímenes, principalmente en la longitud del basidioma, en algunos casos con el doble tamaño (55 cm) respecto al reportado previamente para la especie. A diferencia de los resultados morfológicos, el análisis genético no indicó una diferencia significativa entre los individuos analizados. Sin embargo, los resultados presentes aportan nueva información para la caracterización morfológica de ejemplares para el norte de México, y el primer registro de siete nuevas secuencias utilizando el espaciador interno transcrito y datos de distribución geográfica de esta especie en el norte de México.","PeriodicalId":51157,"journal":{"name":"Southwestern Naturalist","volume":"66 1","pages":"225 - 232"},"PeriodicalIF":0.2,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48907024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NO RELATIONSHIP OBSERVED BETWEEN HABITAT TYPE AND RICKETTSIA PRESENCE IN ECTOPARASITES COLLECTED FROM RODENTS IN SOUTHWESTERN TENNESSEE","authors":"R. A. Butler, R. T. Trout Fryxell, M. Kennedy, A. Houston, E. K. Bowers, L. Coons, D. Paulsen, J. Baxter","doi":"10.1894/0038-4909-66.3.233","DOIUrl":"https://doi.org/10.1894/0038-4909-66.3.233","url":null,"abstract":"Abstract Ectoparasites such as fleas and ticks are important vectors of pathogens affecting humans, domesticated animals, and wildlife. Habitat type is a major determinant of abundance of small mammals, abundance of associated ectoparasites, and community composition, but the role habitats have in the association of a pathogen occurring within an ectoparasite is currently unknown. We tested the hypothesis that natural history and habitat type of small mammal hosts shape the probability of their ectoparasites serving as hosts for a pathogen. Ectoparasites were collected from small mammals captured in mature hardwood forests, midrotation, previously thinned loblolly pine plantations, and early successional field habitats. The ectoparasites were screened for Rickettsia using genus-specific polymerase chain reaction. Rodents consisted of 14 Peromyscus leucopus with 28.57% Rickettsia-infected ectoparasites, 25 Sigmodon hispidus with 8.86% infected ectoparasites, and 2 Microtus pinetorum with 0.00% infected ectoparasites. Rickettsia was identified in 13 (12.38%) of the 105 ectoparasites screened from 41 (17.01%) of the 241 small mammal hosts. No significant association between host traits, habitat type, and Rickettsia-positive ectoparasites was detected. Although habitat type and availability of small mammals may shape the abundance and composition of ectoparasite communities, results of our study suggested these determinants likely do not influence the probability of Rickettsia infection. Resumen Ectoparásitos como pulgas y garrapatas son vectores importantes de patógenos que afectan a los seres humanos, a los animales domésticos y a la vida silvestre. El tipo de hábitat es un factor muy determinante de la abundancia de los mamíferos pequeños, la abundancia de ectoparásitos asociados y la composición de la comunidad. Sin embargo, se desconoce el papel que desempeña el hábitat en la asociación de los patógenos que viven dentro de un ectoparásito. Probamos la hipótesis de que la historia natural y el tipo de hábitat donde viven los mamíferos pequeños, influyen en la probabilidad de que sus ectoparásitos sean huéspedes de un patógeno. Los ectoparásitos se recolectaron de mamíferos pequeños capturados en bosques caducifolios maduros, bosques en rotación intermedia, plantaciones de pino piñonero previamente raleadas y campos de sucesión temprana. Los ectoparásitos se revisaron para detectar Rickettsia mediante la reacción en cadena de la polimerasa específica para el género. Los roedores muestreados fueron 14 Peromyscus leucopus con 28.57% de ectoparásitos infectados con Rickettsia, 25 Sigmodon hispidus con 8.86% de ectoparásitos infectados y 2 Microtus pinetorum con 0.00% de ectoparásitos infectados. La Rickettsia se identificó en 13 (12.38%) de los 105 ectoparásitos examinados de 41 (17.01%) de los 241 mamíferos pequeños huéspedes. No se detectó una asociación significativa entre las características del huésped, el tipo de hábitat y los ectoparásitos pos","PeriodicalId":51157,"journal":{"name":"Southwestern Naturalist","volume":"66 1","pages":"233 - 239"},"PeriodicalIF":0.2,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44039603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"USE OF REGIONAL BREEDING BIRD SURVEYS TO ESTIMATE BIRD POPULATIONS IN BIG THICKET NATIONAL PRESERVE","authors":"D. Twedt, Clifford E. Shackelford","doi":"10.1894/0038-4909-66.3.240","DOIUrl":"https://doi.org/10.1894/0038-4909-66.3.240","url":null,"abstract":"Abstract We used data collected during surveys of seven North American Breeding Bird Survey routes in eastern Texas to estimate avian populations within Big Thicket National Preserve. On only 61 of the 350 count locations located along these routes did observers monitor birds within the boundaries of this preserve. On selected routes, we recorded initial bird detections during the 3-min bird count within 1-min time intervals and within two distance classes (≤50 or >50 m). We used these data, combined with data collected using standard Breeding Bird Survey protocols during 2009–2016, to estimate detection probabilities and effective detection radii for commonly detected species. For species often detected in flocks, we estimated these parameters for group detections. From these parameters, we estimated regional densities for 60 species. Because habitat within Big Thicket National Preserve differed from habitat along surveyed routes, for each species we adjusted the projected population estimate to account for the relationship between density of detected birds and habitat descriptors from the National Land Cover database. On the basis of our estimates of regional density of each species, and accounting for differences in habitat availability, we estimated that commonly detected avian species comprises a population of 192,201 breeding birds (95% confidence interval = 144,269–340,790) within Big Thicket National Preserve. Resumen Utilizamos datos recopilados durante estudios de siete rutas del North American Breeding Bird Survey en el este de Texas para estimar las poblaciones de aves dentro de Big Thicket National Preserve. Observadores monitorearon a las aves dentro de esta reserva en solo 61 de los 350 lugares de conteo ubicados a lo largo de estas rutas . En rutas seleccionadas, detecciones iniciales de aves durante 3 minutos se registraron en intervalos de tiempo de 1 minuto y dentro de 2 clases de distancia (≤ 50 m o > 50 m). Utilizamos estos datos, combinados con los datos recopilados utilizando el método estándar del Breeding Bird Survey durante 2009–2016 para estimar probabilidades de detección y radios de detección para especies comúnmente detectadas. Para las especies detectadas a menudo en bandadas, estimamos estos parámetros para las detecciones de grupo. A partir de estos parámetros, estimamos las densidades regionales para 60 especies. Debido a que el hábitat dentro de Big Thicket National Preserve difería del hábitat a lo largo de las rutas monitoreadas, para cada especie ajustamos su población estimada proyectada para tener en cuenta la relación entre la densidad de aves detectadas y los descriptores de hábitat de la base de datos National Land Cover. Con base en nuestras estimaciones de la densidad regional de cada especie, y teniendo en cuenta diferencias en la disponibilidad de hábitat, estimamos que las especies de aves comúnmente detectadas comprenden una población de 192,201 aves reproductoras (IC95% = 144,269–340,790) dentro d","PeriodicalId":51157,"journal":{"name":"Southwestern Naturalist","volume":"66 1","pages":"240 - 249"},"PeriodicalIF":0.2,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44586538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EVALUATION OF A TRANSLOCATION OF CROCODYLUS MORELETII INDIVIDUALS TO ÁREA DE PROTECCIÓN DE FLORA Y FAUNA YUM BALAM, QUINTANA ROO, MEXICO","authors":"Julio César Gutiérrez-Ramírez, M. González-Jáuregui, Benjamín Morales-Vela, J. R. Cedeño-Vázquez","doi":"10.1894/0038-4909-66.3.250","DOIUrl":"https://doi.org/10.1894/0038-4909-66.3.250","url":null,"abstract":"Abstract We rescued 22 Crocodylus moreletii adult individuals from an area designated to become a theme park in the Riviera Maya tourist corridor in Quintana Roo, Mexico. They were translocated between January and February 2018 to Río Yalikín stream located in the wildlife sanctuary Área de Protección de Flora y Fauna Yum Balam. Our goal was to evaluate the survival and dispersal of the translocated specimens, and to measure their possible impact on the local crocodile populations (C. moreletii, C. acutus, and possible hybrids) already established in the Yum Balam Protected Area. We conducted diurnal and nocturnal field surveys from January to June 2019 to search for translocated crocodiles, and to estimate abundance, size class structure, and sex ratio of the population (local and translocated crocodiles). Ten of the translocated crocodiles (five females and five males) were tagged with very high frequency (VHF) radiotransmitters with global positioning system datalogger. After spending 36 h at a fixed-point location and utilizing a boat to track animals (2,748 km traveled and 254 h expended), we did not recapture any of the translocated crocodiles, and we failed to detect individuals with radiotransmitters. We detected, however, VHF signals from three individuals outside of Río Yalikín area during an aerial survey. The spatial distribution of all crocodiles was aggregated with possible segregations as they moved away from the stream's delta. The estimated total abundance was 26 crocodiles with an encounter rate of 3.64 individuals/km. The population structure by size classes consisted of yearlings (1.14%), juveniles (9.66%), subadults (11.36%), adults (13.64%), and large adults (5.68%). An important fraction of sightings (58.52%) was assigned to the “Eyes Only” category. Twenty-six crocodiles were captured (12 C. moreletii and 14 C. acutus). The observed sex ratio for both species was 1:1 during our study. Our results concerning the dynamics of the local population and the possible impacts of the introduced individuals provide relevant information to determine the best practices that wildlife managers should pursue to achieve sustainable management and conservation of crocodiles. Resumen Rescatamos 22 individuos adultos de Crocodylus moreletii de un área designada para convertirse en un parque temático en el corredor turístico de la Riviera Maya en Quintana Roo, México. Estos individuos fueron translocados entre enero y febrero de 2018 al arroyo Río Yalikín ubicado en el santuario de vida silvestre Área de Protección de Flora y Fauna Yum Balam. Nuestro objetivo era evaluar la supervivencia y la dispersión de los ejemplares translocados y medir su posible impacto en la población local de cocodrilos (C. moreletii, C. acutus y posibles híbridos) ya establecida en el Área Protegida de Yum Balam. Realizamos muestreos de campo diurnos y nocturnos de enero a junio de 2019 para ubicar cocodrilos translocados y estimar la abundancia, la estructura de cl","PeriodicalId":51157,"journal":{"name":"Southwestern Naturalist","volume":"66 1","pages":"250 - 260"},"PeriodicalIF":0.2,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42617524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DEPOSITION AND DECOMPOSITION OF UNGULATE DUNG AND ASSOCIATED NITROGEN INPUTS ON A DRYLAND RIVER FLOODPLAIN","authors":"D. C. Andersen","doi":"10.1894/0038-4909-66.3.213","DOIUrl":"https://doi.org/10.1894/0038-4909-66.3.213","url":null,"abstract":"Abstract Nutrient dynamics in dryland river floodplains remain poorly understood, particularly where ungulate herbivory results in significant dung deposition. I assessed organic matter and nitrogen (N) losses from elk (Cervus elaphus) dung deposited on the floodplain of the unregulated Yampa River in semiarid northwestern Colorado. Intact elk fecal pellets were placed on relatively high, vegetated floodplain surfaces in loose piles or enclosed in mesh bags and monitored for up to 847 days. No pellets were inundated by Yampa floodwaters. Modified exponential decay models indicated intact pellets lost 50% of their initial ash-free dry matter (AFDM) and N content in 980 and 903 days, respectively, and 90% in 2,224 and 1,820 days, respectively. Macroinvertebrates appeared to be unimportant in decomposition. Based on dung deposited in ≤19 permanent 28-m2 plots monitored from 1999 to 2006, elk added an average 13.7 g AFDM·m–2 and 200 mg N·m–2 to the floodplain each year. Mule deer (Odocoileus hemionus) added an average of 2.85 g AFDM·m–2 and 68.2 mg N·m–2 each year. Fecal N deposited on the floodplain, but derived from foraging outside it, would add to the N in flood-deposited sediment hypothesized to explain the N buildup observed during succession on the Yampa floodplain. The roles of large herbivores and dung decay processes in N cycling and dynamics on this and other dryland floodplains warrant greater attention. Resumen La dinámica de nutrientes en las llanuras aluviales de tierras secas sigue siendo poco conocida, especialmente cuando la presencia de herbívoros ungulados tiene como resultado cantidades significativas de deposiciones de estiércol. Evalué la pérdida de materia orgánica y nitrógeno (N) del estiércol de alce (Cervus elaphus) depositado en la llanura aluvial del río Yampa, un río no regulado, en la zona semiárida del noroeste de Colorado. Se colocaron heces fecales intactas de alce en montículos sueltos y en bolsas de malla en superficies de la llanura aluvial relativamente altas y con vegetación, y se monitorizaron durante 847 días. El agua de la crecida del río Yampa no inundó las heces fecales. Los modelos modificados de descomposición exponencial indicaron que las heces intactas perdieron el 50% de su materia seca sin cenizas (AFDM, por sus siglas en inglés) y de su contenido de nitrógeno iniciales en 980 y 903 días, respectivamente, y el 90% en 2,224 y 1,820 días, respectivamente. Los macroinvertebrados no parecen importantes en la descomposición. En base al estiércol depositado en ≤19 parcelas permanentes de 28 m2, monitorizadas desde 1999 hasta 2006, los alces añadieron una media de 13.7 g AFDM·m–2 y 200 mg N·m–2 a la llanura aluvial cada año. Los ciervos bura (Odocoileus hemionus) añadieron una media de 2.85 g AFDM·m–2 y 68.2 mg N·m–2 a la llanura aluvial cada año. El nitrógeno fecal depositado en la llanura aluvial pero derivado del forrajeo fuera de ella se sumaría al nitrógeno en el sedimento depositado por inundaciones, q","PeriodicalId":51157,"journal":{"name":"Southwestern Naturalist","volume":"66 1","pages":"213 - 224"},"PeriodicalIF":0.2,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42609572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RECENT COLONIZATION OF NESTING CANADA GEESE (BRANTA CANADENSIS) IN GLEN AND GRAND CANYONS","authors":"S. W. Carothers, Tanner S. Carothers","doi":"10.1894/0038-4909-66.3.203","DOIUrl":"https://doi.org/10.1894/0038-4909-66.3.203","url":null,"abstract":"Abstract Nesting Canada geese (Branta canadensis) appear to be colonizing portions of the Colorado River in Glen Canyon and Grand Canyon, Arizona. We report the first appearance of nesting geese in this area with one record in the 1950s, followed several decades later by single-pair nesting records in 2001, 2012, 2013, and 2016, increasing to two pairs in 2018, five or six pairs in 2019, and at least two pairs in 2020. Our recent field observations (2018–2020) document that nesting geese are currently successfully raising broods in two geographically distinct areas separated by over 300 km along the river corridor in Grand Canyon: a 4-km area from river kilometer 80 to river kilometer 84 in eastern Grand Canyon, and a 54-km area from river kilometer 392 to river kilometer 446 in western Grand Canyon. The eastern nesting area is dominated by riparian habitat that has proliferated in a relatively stabilized shoreline since Glen Canyon Dam began regulating the river in 1963. The western nesting area is within the fluctuating inflow of the river with Lake Mead, a geomorphologically distinct area where >20 years of drought-induced declining reservoir levels have exposed sediments deposited when Lake Mead was higher than at present (1950s–2001). Two factors likely contribute to the increased presence of nesting geese in Grand Canyon, including (1) expanding populations of nonmigratory, resident geese and the southward expansion of their historic breeding range and (2) the availability of nesting habitat along the Colorado River today that may not have existed historically. Resumen Los gansos canadienses (Branta canadensis) anidando parecen estar colonizando ciertos tramos del río Colorado del Glen Canyon y del Grand Canyon, Arizona. Los primeros reportes de estos gansos anidando en esta área corresponden a un avistamiento en los años 50, seguidos varias décadas después por registros de un solo par de gansos anidando en 2001, 2012, 2013 y 2016. El número de registros aumentó a dos pares de avistamientos en 2018, a cinco o seis pares en 2019 y a por lo menos a dos pares en 2020. Nuestras recientes observaciones de campo (2018–2020) documentan que los gansos anidando están actualmente criando a sus polluelos con éxito en dos áreas geográficas distintas separadas por más de 300 kilómetros a lo largo del corredor del río en el Grand Canyon: en un área de 4 kilómetros de kilómetro-río 80 a kilómetro-río 84 en el tramo este del Grand Canyon, y en un área de 54 kilómetros de kilómetro-río 393 a kilómetro-río 446 en el tramo oeste del Grand Canyon. El área de nidificación más al este es un hábitat de humedales que ha ido proliferando en la zona ribereña desde que la represa Glen Canyon comenzó a regular el flujo del río en 1963. El área de nidificación más al oeste se encuentra dentro de la zona de influjo fluctuante del río con el lago Mead, que corresponde a un área geomorfológica distinta donde la disminución del nivel de la represa debido a una sequía de má","PeriodicalId":51157,"journal":{"name":"Southwestern Naturalist","volume":"66 1","pages":"203 - 212"},"PeriodicalIF":0.2,"publicationDate":"2022-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42739893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}