Western North American Naturalist最新文献

{"title":"Ecosystem Structure and Function across Western Dryland Ecosystems: A Cross-Site Comparison of Semiarid Ecosystem Types in Colorado and Wyoming","authors":"C. Beltz, W. Lauenroth, I. Burke","doi":"10.3398/064.083.0308","DOIUrl":"https://doi.org/10.3398/064.083.0308","url":null,"abstract":"Abstract. Drylands extend over large portions of the globe, including a significant share of the western United States, yet they remain understudied. We examined ecosystem structure and function at 3 semiarid dryland sites in Colorado and Wyoming, each of which was dominated by a different ecosystem type and plant community—shortgrass steppe, mixed-grass prairie, and sagebrush steppe. This initial study was conducted to fill gaps in knowledge about how sagebrush steppe compares to dryland grasslands in the western United States. Soil respiration was higher at the sagebrush steppe than at the 2 grassland sites (P = 0.001). Aboveground biomass, microbial abundance, and soil inorganic nitrogen were not significantly different among ecosystem types after the 2017 summer season. Soil carbon was largely similar across all ecosystem types down to 5 cm, with more widespread differences among all sites in the 5–10 cm depth. Plant, bacterial, and fungal communities all differ between sites (P < 0.001), though they have large numbers of shared species among the sites. Despite these differences in ecosystem structure between ecosystem types, we found only a single significant difference in ecosystem function: soil respiration was higher at the sagebrush steppe than at the other 2 sites. Given the importance of global drylands, broad and high-powered systematic sampling across dryland types would be beneficial to understanding the extent of similarities and ability to extrapolate across and within dryland ecosystem types. Resumen. Si bien gran parte del mundo está compuesto de tierras áridas, incluida una parte significativa del oeste de los Estados Unidos, estas aún permanecen sin ser estudiadas. Examinamos la estructura y función de los ecosistemas en tres sitios de tierras áridas semiáridas en Colorado y Wyoming, cada uno de los cuales estaba dominado por un tipo de ecosistema y una comunidad de plantas diferentes: la estepa de pasto corto, la pradera de pasto mixto y la estepa de artemisa. El estudio inicial se llevó a cabo para conocer cómo se compara la estepa de artemisa con los pastizales de tierras áridas en el oeste de los Estados Unidos. La respiración del suelo fue mayor en la estepa de artemisa que en los dos sitios de pastizales (P = 0.001). La biomasa aérea, la abundancia microbiana y el nitrógeno inorgánico del suelo no fueron significativamente diferentes entre los tipos de ecosistemas después de la temporada del verano de 2017. El carbono del suelo fue similar en todos los tipos de ecosistemas hasta 5 cm, con diferencias más generalizadas entre todos los sitios a una profundidad de 5 a 10 cm. Las comunidades de plantas, bacterias y hongos difirieron entre los sitios (P < 0.001), aunque comparten un gran número de especies. A pesar de estas diferencias en la estructura del ecosistema entre los tipos de ecosistemas, encontramos solo una única diferencia significativa en la función del ecosistema: la respiración del suelo fue más alta en la est","PeriodicalId":49364,"journal":{"name":"Western North American Naturalist","volume":"295 1 1","pages":"388 - 402"},"PeriodicalIF":0.6,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139315262","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":"Field-Based Selenium Partitioning Coefficients, Trophic Transfer Factors, and Otolith Time-Series Analyses for a Walleye Community from an Ecotonal Plains Reservoir, Colorado. III.","authors":"S. J. Herrmann, Del Wayne R. Nimmo, Lynn M. Herrmann-Hoesing, Igor V. Melnykov, Norman M. Halden","doi":"10.3398/064.083.0307","DOIUrl":"https://doi.org/10.3398/064.083.0307","url":null,"abstract":"Abstract. Little is known about partitioning coefficients, tissue bioaccumulation, trophic transfer, and otolith time-series analyses of selenium (Se) in a fishery dominated by walleye (Sander vitreus) that consume multiple prey species and occur in a Se-rich reservoir. Concentrations of dissolved total Se in Pueblo Reservoir water consistently exceeded the current EPA criterion benchmark for lentic aquatic ecosystems. The major objectives of this study were to analyze Se in diet-borne consumables of a walleye fishery and perform time-series trend tests of 21 walleye sagittae. In contrast to previous reports, we proposed investigating Se partitioning from water to subsequent trophic levels in a meso-eutrophic ecotonal reservoir using concentrations in water, sediment, periphyton, filamentous algae, diatom mats, chironomids, whole crayfish, muscle of stocked rainbow trout (Oncorhynchus mykiss), whole gizzard shad (Dorosoma cepedianum), and tissues of walleye analyzed by ICP-MS. The indicator values for the level-1 (water to particulate) partitioning coefficients (Kd values) or enrichment factors were as high as 2325 L/kg dw and as low as 588 L/kg dw. Of 36 trophic transfer factors (TTFs) for invertebrates, 33 were >1, while for walleye tissues, 57 of 90 TTFs were <1. For gizzard shad, 8 of 8 TTFs were >1.8. We proposed nonlinear food-web exposure scenarios for walleye and gizzard shad in the Pueblo Reservoir ecosystem. Temporal series analyses of walleye sagittal otoliths showed significantly increasing annular Se concentrations over time for 19 of 21 walleye. Concentrations of Se in whole-body gizzard shad were greater than Se levels in the 3 highest walleye tissues (liver, gill, and kidney). This is the first comprehensive Se study that addresses nearly all components of a walleye ecosystem. Resumen. Poco se conoce acerca de los coeficientes de fraccionamiento, bioacumulación de tejido, transferencia trófica y análisis de series temporales de otolitos de selenio (Se) en la pesca dominada por peces leucoma, quienes consumen múltiples especies de presas que están presentes en un yacimiento rico en seleníferos. Las concentraciones totales de selenio disuelto en el agua del “Embalse de Pueblo” sistemáticamente excedieron el criterio de referencia actual de la EPA para los ecosistemas acuáticos lénticos. El principal objetivo de este trabajo fue analizar la presencia y cantidad de selenio (Se) consumido a través de la dieta en una pesquería de leucomas, así como analizar su tendencia utilizando series de tiempo en 21 peces leucoma sagitaria. A diferencia de reportes previos, en este trabajo investigamos la fragmentación de selenio en el agua en los niveles tróficos posteriores, en un reservorio ecotonal meso-eutrófico, muestreando concentraciones en agua, sedimentos, perifiton, algas filamentosas, esteras de diatomeas, quironómidos, cangrejos de río, músculo de trucha arcoiris (Oncorhynchus mykiss), peces sábalo molleja (Dorosoma cepedianum) y tejido","PeriodicalId":49364,"journal":{"name":"Western North American Naturalist","volume":"35 1","pages":"365 - 387"},"PeriodicalIF":0.6,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139316636","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":"Prescribed Fire and Changes in Annual Precipitation Alter Biocrust Cover in a Coastal Grassland","authors":"Brianne Palmer, Dawn Lawson, David A. Lipson","doi":"10.3398/064.083.0303","DOIUrl":"https://doi.org/10.3398/064.083.0303","url":null,"abstract":"Abstract. Prescribed fires are often used as a management tool in grasslands to promote the growth of desired plant species. These fires also impact other ecological communities where they occur. One ecological community that is often overlooked regarding fire is biological soil crusts (biocrusts). Biocrusts contain an assemblage of cyanobacteria, lichens, and bryophytes living on the soil surface and are important for nutrient cycling and soil stability. Here, we used prescribed burns in a California coastal grassland on San Clemente Island (SCI) to understand how fire impacts biocrust cover. Two sites were burned in a prescribed fire in 2012 and then again in 2017, and one site was burned in a wildfire in 2012 and a prescribed fire in 2017. We compared the percent cover of biocrusts in the burned and unburned plots in 2018 and 2019. However, precipitation differed drastically between sampling years; therefore, we also assessed the role of precipitation in moderating biocrust cover in the burned and unburned plots. In 2018 and 2019, one and two years after the last prescribed fire, the burned plots had more cyanobacterial biocrust cover than the controls. Annual precipitation had a negative effect on cyanobacterial biocrust cover, though lichen- and bryophyte-dominated biocrusts increased with increasing precipitation. The abundance of cyanobacterial biocrusts in the burned plots suggests either a level of recovery after the fire or the ability of biocrusts to withstand a grassland fire, though the effect is mediated by precipitation. Resumen. La quema prescrita se utiliza a menudo como una herramienta de gestión de pastizales para promover el crecimiento de las especies de plantas deseadas, pese a que estos incendios también tienen un impacto en otras comunidades ecológicas. Una comunidad ecológica que a menudo se pasa por alto con respecto a la quema son las costras biológicas del suelo (biocostras). Las biocostras contienen un conjunto de cianobacterias, líquenes y briófitas que viven en la superficie del suelo y son importantes para el ciclo de nutrientes y la estabilidad del suelo. Llevamos a cabo quemas prescritas en un pastizal costero de la isla de San Clemente (SCI) en California para comprender cómo el fuego afecta la cubierta de biocostra. Se quemaron dos sitios en un incendio prescrito en 2012 y luego nuevamente en 2017, uno de los sitios se quemó en un incendio forestal en 2012 y posteriormente un incendio prescrito en 2017. Comparamos el porcentaje de cobertura de biocostras en las parcelas quemadas y no quemadas en 2018 y 2019. Sin embargo, la precipitación difirió drásticamente entre los años de muestreo; por lo tanto, también evaluamos el papel de la precipitación en el crecimiento de la cobertura de biocostras en las parcelas quemadas y no quemadas. En 2018 y 2019, uno y dos años después de la última quema prescrita, las parcelas quemadas tenían mayor cobertura de biocostras de cianobacterias que la de los controles. La precipi","PeriodicalId":49364,"journal":{"name":"Western North American Naturalist","volume":"132 1","pages":"325 - 334"},"PeriodicalIF":0.6,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139317733","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":"Effects of Fire on Kangaroo Rats in the San Joaquin Desert of California","authors":"David J. Germano, L. Saslaw, B. Cypher, Linda Spiegel","doi":"10.3398/064.083.0304","DOIUrl":"https://doi.org/10.3398/064.083.0304","url":null,"abstract":"Abstract. Fire can alter ecological communities, particularly those that are not fire-adapted, such as desert communities. We examined the effects of fire on rodent communities in the San Joaquin Desert of central California. Of particular interest were the effects on kangaroo rats (Dipodomys spp.) including 2 rare species, the giant kangaroo rat (D. ingens) and the short-nosed kangaroo rat (D. nitratoides brevinasus). Lightning caused multiple fires in arid scrub habitat in western Kern County in 1993. We trapped rodents at 7 sites along paired transects, with one transect in a burned area and one in a nearby unburned area. We conducted 5 trapping sessions from July 1993 to November 1995. Kangaroo rat abundance trends were similar between burn and control transects across the sessions. We also compared abundance of giant kangaroo rats between a trapping grid in an area subjected to controlled burning and a grid in a nearby unburned area on the Carrizo Plain in eastern San Luis Obispo County. Abundance trends were similar between the burned and unburned grids, although kangaroo rat numbers were maintained on the burn site over several sessions compared to the unburned site. We did not detect any adverse effects to kangaroo rat abundance from fire in the 2 study areas. Sheltering in burrows and storing seed underground may mitigate the effects of fire on kangaroo rats. Also, fire may actually benefit kangaroo rats by reducing groundcover density, thereby improving their mobility and predator detection. We do not recommend fire as a management strategy, however, because burning may adversely impact other species, kill shrubs, and erode air quality in a region where the air is chronically polluted. Resumen. Los incendios pueden alterar las comunidades ecológicas, especialmente aquellas comunidades desérticas que no están adaptadas al fuego. Examinamos el efecto de los incendios en las comunidades de roedores del desierto de San Joaquín en el centro de California, con particular interés en su efecto sobre las ratas canguro (Dipodomys spp.), incluidas dos especies raras, la rata canguro gigante (D. ingens) y la rata canguro de hocico corto (D. nitratoides brevinasus). Los relámpagos causaron múltiples incendios en hábitats de matorrales áridos en el oeste del condado de Kern en 1993. Atrapamos roedores en siete sitios a lo largo de transectos emparejados con un transecto en un área quemada y otro en un área cercana no quemada. Llevamos a cabo cinco sesiones de captura desde julio de 1993 hasta noviembre de 1995. Las tendencias de abundancia de ratas canguro fueron similares entre los transectos quemados y control en todas las sesiones. También comparamos la abundancia de ratas canguro gigantes entre un cuadrante de captura en un área sujeta a quema controlada y un cuadrante en un área cercana no quemada en Carrizo Plain en el este del condado de San Luis Obispo. Las tendencias de abundancia fueron similares entre los cuadrantes quemados y no quemados,","PeriodicalId":49364,"journal":{"name":"Western North American Naturalist","volume":"4 1","pages":"335 - 344"},"PeriodicalIF":0.6,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139320484","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":"Spatial Ecology of the Texas Alligator Lizard (Gerrhonotus infernalis) in Blanco County, Texas","authors":"Corey M. Fielder, Wade A. Ryberg, Danielle K. Walkup, Jared M. Holmes, Toby J. Hibbitts","doi":"10.3398/064.083.0302","DOIUrl":"https://doi.org/10.3398/064.083.0302","url":null,"abstract":"Abstract. Texas Alligator Lizards (Gerrhonotus infernalis) range from Central Texas into adjacent northeastern Mexico, and published ecological studies on their terrestrial and arboreal movement patterns are lacking. We used radiotelemetry to assess movements, annual home range, and arboreal activity of G. infernalis at Bamberger Ranch Preserve, Blanco County, Texas, to provide baseline ecological data for populations occurring in the northernmost extent of the species' range. Movement patterns were influenced by temporal (e.g., seasonal) and behavioral cues (e.g., breeding period), but generally no differences were observed between sexes. Annual home range varied, but males averaged larger 95% MCP (minimum convex polygon) annual home ranges, while females averaged larger 50% MCP core use areas, although we were unable to test for differences due to low sample sizes. Males and females exhibited similar arboreal trends, but arboreal activity did vary by season and diurnal period. Most arboreal activity occurred during the summer and late spring, with less during the fall and winter months. Gerrhonotus infernalis, on average, inhabited higher perch sites during the evening and morning diurnal periods and lower perch sites during the afternoon periods. These findings provide novel insights into the ecology of G. infernalis in Central Texas and will aid in future management activities. Resumen. El Cantil de Tierra (Gerrhonotus infernalis) se distribuye desde la parte central del estado de Texas en los Estados Unidos, hasta la zona fronteriza del Noreste de México. La información ecológica publicada formalmente sobre sus patrones de movimiento tanto arbóreos como terrestres es muy escasa y con la finalidad de proveer información ecológica básica sobre las poblaciones existentes en la parte mas al norte de su rango de distribución natural, hemos utilizado radiotelemetria para analizar el área de distribución anual y la actividad arbórea de G. infernalis en Bamberger Ranch Preserve, en el condado de Blanco, Texas. De movimiento en G. infernalis fueron influenciados por señales ambientales (estaciones) y de comportamiento (periodo de reproducción), pero en términos generales, no se encontraron diferencias entre sexos. El rango anual de distribución espacial fue variable y los machos promediaron un mayor uso total del espacio, mientras que las hembras promediaron un uso mayor de sus áreas de preferencia, aunque dicha diferencia no fue significativa. Machos y hembras presentaron hábitos arbóreos similares, aunque vale destacar que la actividad arbórea presento variaciones estacionales y también durante el periodo diurno. La mayoría de la actividad arbórea ocurrió durante el verano y el fin de la primavera, mostrando una reducción en el final del otoño y el invierno. En promedio, G. infernalis utilizo sitios de percha más altos durante las últimas horas de la tarde y las primeras horas de la mañana. Los sitios de percha de menor elevación fueron utilizados ","PeriodicalId":49364,"journal":{"name":"Western North American Naturalist","volume":"207 1","pages":"315 - 324"},"PeriodicalIF":0.6,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139320326","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":"Late Pleistocene Herpetofauna from Two High-Elevation Caves in the Upper Gunnison Basin, Colorado","authors":"Jim I. Mead, S. Emslie, D. Meltzer","doi":"10.3398/064.083.0310","DOIUrl":"https://doi.org/10.3398/064.083.0310","url":null,"abstract":"Abstract. Cement Creek and Haystack caves in Colorado have produced a diverse record of high-elevation late Quaternary mammals. Intermixed with the abundant mammalian remains were rare occurrences of amphibian and reptile fossils reported here. Cement Creek Cave (2860 m elevation) contained the fossils of only a few anurans and a limited number of snakes, whereas Haystack Cave, at a substantially lower elevation (2450 m), contained the fossils of a salamander, a larger number of snakes, and an extensive number of lizard remains, yet no anurans. The 2 faunas are overall distinct in composition, and, although not diverse or abundant in terms of species or number of faunal remains, they provide a rare and exceptional record of a late Pleistocene high-elevation herpetofauna from the Intermountain West. Resumen. Las cuevas Cement Creek y Haystack en Colorado han producido un diverso registro de mamíferos de gran altitud del Cuaternario tardío. Entre los abundantes restos de mamíferos, se registraron raros casos de anfibios y reptiles, los cuales reportamos a continuación. En la cueva Cement Creek (2860 m de elevación) se encontraron solo unos pocos anuros y un número limitado de serpientes. Mientras que, en la cueva Haystack, a una elevación sustancialmente más baja (2450 m de elevación), se encontraron una salamandra, una mayor cantidad de serpientes y una gran cantidad de restos de lagartos, pero no anuros. Las dos faunas son distintas en su composición en general y, aunque no son diversas ni abundantes en términos de especies o número de restos de fauna, proporcionan un registro único y excepcional de una herpetofauna de alta elevación del Pleistoceno tardío del oeste intermontañoso.","PeriodicalId":49364,"journal":{"name":"Western North American Naturalist","volume":"178 1","pages":"413 - 426"},"PeriodicalIF":0.6,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139320378","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":"Potentially Adaptive Significance of Genome Size Diversity across Ecological Gradients and Seed Size in Ivesia (Rosaceae)","authors":"I. Borokini, Shaun R. Broderick, Zhi Gao, Joshua M. Hallas, James A. Birchler, Mary M. Peacock","doi":"10.3398/064.083.0301","DOIUrl":"https://doi.org/10.3398/064.083.0301","url":null,"abstract":"Abstract. Variation in genome size across taxa has been explained using neutral and nonadaptive theories; however, genome size variation among taxonomic groups can also be shaped by natural selection if it correlates with functional traits. This study investigated the potential adaptive significance of genome size in Ivesia, a radiating genus distributed in the western North American desert ecosystems. We estimated the genome size of 34 taxa (including 31 Ivesia taxa, 2 Potentilla taxa, and 1 Horkelia taxon) using flow cytometric methods. For each taxon, leaf samples were collected from 6 individuals in 1 location each; intraspecific genome size variation was investigated using samples collected from 11 Ivesia webberi populations. The results showed an 8.1-fold variance in genome size, ranging from 0.73 pg/2C in I. baileyi var. beneolens to 5.91 pg/2C in I. lycopodioides var. megalopetala. Only 6 taxa, with a genome size >1.5 pg/2C, significantly differed from the remaining taxa. Genome size in Ivesia is relatively small, which is typical of plants living in stressful environments. Also, genome size was significantly correlated with seed size and actual evapotranspiration both within I. webberi and among Ivesia taxa, thus supporting the predictions of the nucleotype theory and suggesting an adaptive significance of genome size in the genus. Genome size in I. webberi is mostly statistically nonsignificant; however, populations near the center of the species' known range have significantly larger genomes, which decrease in size toward the marginal populations. This intraspecific genome size gradient from range center toward range margins could be attributed to patterns of gene flow and geographic isolation. Resumen. La variación en el tamaño del genoma entre los taxones se ha explicado utilizando teorías neutrales y no adaptativas. Sin embargo, la variación del tamaño del genoma entre grupos taxonómicos también puede estar determinada por selección natural si se correlaciona con rasgos funcionales. Este estudio investigó la posible importancia adaptativa del tamaño del genoma en Ivesia, un género radiante distribuido en los ecosistemas desérticos del oeste de Norteamérica. Estimamos el tamaño del genoma de 34 taxones, incluidos 31 taxones de Ivesia y dos taxones adicionales de Potentilla y un taxón de Horkelia, utilizando métodos de citometría de flujo. Para cada taxón, recolectamos muestras de hojas de seis individuos en una localización cada uno. Mientras, investigamos la variación del tamaño del genoma intraespecífico utilizando muestras recolectadas de 11 poblaciones de Ivesia webberi. Los resultados mostraron una variación de 8.1 veces en el tamaño del genoma, que va desde 0.73 pg/2C en I. baileyi var. beneolens hasta 5.91 pg/2C en I. lycopodioides var. megalopetala. Solo seis taxones, con un tamaño de genoma >1.5 pg/2C, fueron significativamente diferentes al resto de los taxones. El tamaño del genoma en Ivesia es relativamente pequeño, lo cu","PeriodicalId":49364,"journal":{"name":"Western North American Naturalist","volume":"27 1","pages":"301 - 314"},"PeriodicalIF":0.6,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139321259","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":"Floral Constancies of Flies and Native Bees Visiting Ceanothus perplexans (Rhamnaceae) Flowers in Western Arizona","authors":"W. Wiesenborn","doi":"10.3398/064.083.0311","DOIUrl":"https://doi.org/10.3398/064.083.0311","url":null,"abstract":"Abstract. Ceanothus perplexans (Rhamnaceae) is a chaparral and montane shrub found mostly in southern California and northern Baja California, Mexico, and infrequently in western Arizona. The plant produces inflorescences of small, perfect, white or cream flowers during winter to early spring. I examined the pollination of C. perplexans in the Cerbat Mountains in western Arizona during March and April 2022 by collecting flies and native bees on flowers and estimating floral constancies from the proportions of conspecific pollen in pollen loads. Flowers are protandrous with the pistil elongating and the stigmas separating after the anthers lose pollen. Pollen from C. perplexans flowers is tricolporate and interhexagonal in polar view and suboblate in shape with a polar axis length of 17 µm and an equatorial diameter of 19 µm. Flowers were visited by 2 genera of bees (Hymenoptera: Apoidea) in Andrenidae and 9 genera of flies (Diptera) in Syrphidae, Calliphoridae, Anthomyiidae, Muscidae, Tachinidae, and Bombyliidae. Bees were most abundant on flowers, and bee visitors were composed primarily of a Panurginus species followed in abundance by Andrena mackieae. Mean proportions of conspecific pollen in pollen loads were high (>0.80) in all of the species examined, slightly higher in bees (0.99) compared with flies (0.95), and lowest in Syrphidae (0.92). Ceanothus perplexans in western Arizona appears to be pollinated primarily by bees in Panurginus and Andrena and less frequently by various flies. Early flowering by C. perplexans likely reduces competition with other species of plants for pollinators. Resumen. El Ceanothus perplexans (Rhamnaceae) es un arbusto chaparral de las montañas que se encuentra principalmente en el sur de California y el norte de Baja California, México, y ocasionalmente en el oeste de Arizona. La planta produce inflorescencias de flores pequeñas, perfectas, de color blanco o crema durante el invierno hasta principios de la primavera. Examiné la polinización de C. perplexans en las montañas Cerbat en el oeste de Arizona, durante marzo y abril de 2022, recolectando moscas y abejas nativas en las flores y estimando la constancia floral a partir de las proporciones de polen conespecífico en las cargas de polen. Las flores son protándricas con el pistilo alargado y los estigmas separados, después de que las anteras sueltan el polen. El polen de las flores C. perplexans es tricolporado e interhexagonal en vista polar y de forma suboblada con una longitud del eje polar de 17 µm y un diámetro ecuatorial de 19 µm. Las flores fueron visitadas por dos géneros de abejas (Hymenoptera: Apoidea) en Andrenidae y nueve géneros de moscas (Diptera) en Syrphidae, Calliphoridae, Anthomyiidae, Muscidae, Tachinidae y Bombyliidae. Las abejas fueron las más abundantes en las flores, componiéndose principalmente de una especie de Panurginus seguida de Andrena mackieae. Las proporciones medias de polen conespecífico en las cargas de polen fueron altas (>","PeriodicalId":49364,"journal":{"name":"Western North American Naturalist","volume":"3 1","pages":"427 - 434"},"PeriodicalIF":0.6,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139335255","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":"Spatial and Temporal Distribution of Phalaropes (Phalaropus spp.) and Adult Brine Flies (Ephydra spp.) are Linked on Great Salt Lake, Utah","authors":"Maureen G. Frank, Michael R. Conover","doi":"10.3398/064.083.0309","DOIUrl":"https://doi.org/10.3398/064.083.0309","url":null,"abstract":"Abstract. Great Salt Lake (GSL), Utah, is home to some of the world's largest concentrations of Wilson's Phalaropes (Phalaropus tricolor), Red-necked Phalaropes (Phalaropus lobatus), American Avocets (Recurvirostra americana), and Black-necked Stilts (Himantopus mexicanus). These birds spend several weeks on GSL feeding on larvae, pupae, and adult brine flies (Ephydra spp.) before migrating to their wintering grounds in Central and South America. Unfortunately, GSL is shrinking in size and becoming more saline due to water diversions and climate change. Assessing how a smaller and more saline GSL will affect adult brine flies is difficult without knowing their temporal and spatial distribution on GSL. During 2014 and 2015, we measured adult brine fly abundance across different GSL bays during July through September, when phalaropes are staging on the lake. Abundance of adult brine flies showed a bimodal pattern, peaking during weeks 27–29 and then again during week 33. Wilson's Phalaropes were abundant during the first peak in fly numbers but not during the second peak; Red-necked Phalaropes exhibited the opposite pattern. Time of day and weather had little impact on adult fly numbers, with the exception that abundance was positively correlated with air temperature. During this study, a deep brine layer (which is toxic to brine fly larva) existed at water depths >6 m, and adult brine fly abundance was low over these areas. Adult brine fly abundance did not differ with distance from shore or time of day but was positively correlated with salinity. Substrate impacted their abundance, with adult brine flies being 5 times more abundant over microbialites—which are rocky, reef-like structures—than over sand or mud. Phalarope numbers were also highest over microbialites. Thus, most brine fly eggs are laid over microbialites, which is the preferred habitat for brine fly larvae and pupae. Information about the temporal and spatial distribution of adult brine flies is critical for wildlife managers who are tasked with ensuring that GSL will continue to support the large avian populations that depend on GSL's adult brine flies for their existence. Resumen. El lago Great Salt Lake (GSL), en Utah, alberga algunas de las concentraciones más grandes del mundo de falaropo tricolor o falaropo de Wilson (Phalaropus tricolor), falaropo picofino o de cuello rojo (Phalaropus lobatus), avoceta americana (Recurvirostra americana) y cigüeñuela de cuello negro (Himantopus mexicanus). Estas aves pasan varias semanas en GSL alimentándose de larvas, pupas y moscas de salmuera adultas (Ephydra spp.) antes de migrar a sus áreas de invernada en Centro y Sudamérica. Desafortunadamente, el lago GSL se está reduciendo en tamaño y se está volviendo más salino debido a las desviaciones de agua y el cambio climático. Es difícil evaluar cómo estos cambios en el lago afectarán a la mosca de salmuera adulta sin conocer su distribución temporal y espacial. Durante 2014 y 2015, medimos ","PeriodicalId":49364,"journal":{"name":"Western North American Naturalist","volume":"79 1","pages":"403 - 412"},"PeriodicalIF":0.6,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139339757","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":"Reproductively Viable Population of American Black Bears (Ursus americanus) in Lowland Chihuahuan Desert Habitat of Trans-Pecos Texas","authors":"F. Yancey, Stephen Kasper","doi":"10.3398/064.083.0305","DOIUrl":"https://doi.org/10.3398/064.083.0305","url":null,"abstract":"Abstract. During a 6.5-year camera-trap study in Big Bend Ranch State Park (situated in the Trans-Pecos region of West Texas), we documented a persistent breeding population of American black bears (Ursus americanus) in the Solitario region of the park. The habitat in the Solitario, which is an isolated, eroded remnant of volcanic activity, is low-elevation Chihuahuan Desert scrub but includes significant and complex localized topography and prolonged water sources in the form of tinajas. From January 2016 to May 2022, camera traps captured 367,301 photographs. Of these, 868 contained one or more black bears, resulting in 1010 black bear images. Based on age class, size, color, body markings, facial patterns, presence of cubs, and dates of images, we determined that these images represent a minimum of 17 distinct individuals. Adult and subadult bears were identified during each year, yearlings were detected during 4 years, and cubs were noted during 3 years of the study. Based on these data, the Solitario black bears can be considered the westernmost reproductively viable population of American black bears in Trans-Pecos, Texas, and the only one that is situated exclusively in lowland desert habitat. Dietary resources of black bears from other Chihuahuan Desert localities in Texas and northern Mexico are also found in the current study area. This American black bear population is in an area spatially separated from other black bear populations in the region, and we discuss its relevance to the sky island metapopulation hypothesis of recolonization previously proposed for the species in northern Mexico and Trans-Pecos Texas. Resumen. Como resultado de un estudio de seis años y medio de duración en Big Bend Ranch State Park (localizado en la región Trans-Pecos del oeste de Texas) documentamos una población viable de oso negro americano (Ursus americanus) en la región “Solitario” del parque, la cual se encuentra en un remanente volcanico erosionado. La vegetación es desierto Chihuahuense de baja elevación, con topografía local compleja y presencia de cuerpos de agua conocidos como “tinajas”. De enero de 2016 a mayo de 2022 se capturaron 367,301 fotografías con trampas cámara. De ellas, 868 contuvieron uno o más osos negros, para un total de 1010 imágenes con osos negros. Con base en su edad relativa, tamaño, color, marcas corporales, patrones faciales, presencia de oseznos y fechas de las imágenes, determinamos un mínimo de 17 individuos. Se identificaron osos adultos y subadultos cada año, por cuatro años se detectaron juveniles del año, y se registraron oseznos del año durante tres años del estudio. Con base en estos datos, los osos de Solitario pueden considerarse como la población reproductivamente viable más occidental de oso negro americano en Trans-Pecos, Texas, y la única que ocurre exclusivamente en matorral desértico de baja elevación. Los recursos vegetales usados por los osos negros en otras localidades del Desierto Chihuahuense de Texas","PeriodicalId":49364,"journal":{"name":"Western North American Naturalist","volume":"90 1","pages":"345 - 354"},"PeriodicalIF":0.6,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139341592","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}