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At least 55 records · Page 3Linked to original sources
USGS2017

Subsequent-year recaptures at winter sites in three species of shrubland sparrows (Emberizidae)

The tendency by individual birds to return to winter sites in subsequent years can be important in assessing the potential influence of habitat changes during the nonbreeding period. We recaptured five Brewer's ( Spizella breweri ), seven sagebrush ( Artemisiospiza nevadensis ), and three black-throated ( Amphispiza bilineata ) sparrows from 1–3 subsequent years at the same winter location following their initial capture. Two Brewer's and one sagebrush sparrow returned to the same winter location at least 4 years after their initial capture. Levels of feather deuterium indicated that birds captured together on winter sites had different breeding ranges. Although individuals of these species returned to specific sites used in previous years, the low recapture rate suggests that wintering individuals may use an itinerant strategy adapted to seasonal food resources.

Arizona, California, Colorado, Nevada, New Mexico,↗
USGS2017

Survival of the endangered Pima pineapple cactus: Does clearing before prescribed fire alter survival postfire?

Federal land managers and ranchers often use prescribed fire as a tool to reduce invading woody plants within desert grasslands of the arid southwestern United States. Managers must evaluate the threat of the burn toward the health and survival of plants of concern including how preemptive clearing before prescribed fire might benefit these species. One example is the endangered Pima pineapple cactus ( Coryphantha scheeri var. robustispina ), a small hemispheric cactus of desert scrublands and grasslands of south-central Arizona and northern Sonora, Mexico. In 2014, we examined survival of Pima pineapple cactus documented in 2009 or 2010 within grasslands of Buenos Aires National Wildlife Refuge in Arizona. Of the 72 sites observed, 35 had no burn after documentation and 37 experienced prescribed fire. Refuge staff removed vegetation between 0.3 and 3.0 m from the cactus preburn. We found that Pima pineapple cacti in areas subjected to prescribed fire and with preemptive clearing had the same survival statistically as cacti from sites that were not burned.

Arizona↗
USGS2018

Long-Term Movement and Estimated Age of a Paddlefish (Polyodon spathula) in the Arkansas River Basin of Oklahoma

We report the age and distance moved for an individual paddlefish ( Polyodon spathula ) that was tagged March 1998 in the Cimarron River Arm of Keystone Lake, Oklahoma, and snagged by an angler in April 2016 downstream of Eufaula Dam, Oklahoma. The fish was part of a cohort spawned in 1995. At the time of initial capture, the fish measured 795 mm eye–fork length, was estimated to be 3 y old, and 18 y had elapsed before its recapture by an angler in 2016, indicating this fish was 21 y old at recapture. Although paddlefish as old as 27 have been estimated in the Grand River basin of Oklahoma, this is the oldest fish known in the Arkansas River basin of Oklahoma. At the place of its recapture, this fish would have traveled approximately 235 km, passing downstream through three dams before moving upstream to Eufaula Dam.

Oklahoma↗
USGS2017

Population expansion of Humpback chub in western Grand Canyon and hypothesized mechanisms

Humpback chub, Gila cypha , is an endangered warm water fish endemic to the Colorado River basin of southwestern North America. In Grand Canyon National Park, cold hypolimnetic water-release temperatures from Glen Canyon Dam have largely precluded successful spawning and recruitment of humpback chub in the mainstem Colorado River. Therefore, the species has utilized the warmer, more saline, and free-flowing Little Colorado River for its primary spawning habitat and continued existence. Based on long-term fish sampling efforts, we document local recruitment and population expansion of humpback chub in the western Grand Canyon and hypothesize that this is a result of recent warmer mainstem water temperatures. Continued recruitment and population expansion of humpback chub in the western Grand Canyon could potentially reduce extinction risk by providing population redundancy and less reliance upon the Little Colorado River for the species survival in the Grand Canyon.

Arizona↗
USGS2019

Winter and spring diet of the orangebelly darter, Etheostoma radiosum, among tributaries of the Lower Mountain Fork River

Little is known about prey use by the orangebelly darter, Etheostoma radiosum , and what is known has been described from relatively large river systems. We examined prey use by orangebelly darters from first- and second-order tributaries in the Lower Mountain Fork River of southeastern Oklahoma. Adult darters ( n = 141) were captured from five tributaries in 2015, and stomach contents were examined to determine prey use. Aquatic isopods were the most frequently consumed organism. This differs notably from previous reports that insects, primarily dipterans, were the predominant prey for the species.

Oklahoma↗
USGS2019

Viability of Razorback-Flannelmouth Sucker hybrids

Razorback sucker ( Xyrauchen texanus ) and flannelmouth sucker ( Catostomus latipinnis ) live in sympatry in the Colorado River basin. Although morphological intermediates have been described since 1889, hybrids were seemingly rare. Rarity of hybrids was likely attributed to razorback suckers' ability to find conspecific mates throughout the basin. Dams have segmented the Colorado River, altering habitat and isolating native fish populations. As a result, razorback suckers became endangered. Razorback suckers are uncommon in the Colorado River and hybridization could increase because of limited conspecific mates. To understand the impacts of hybridization on recovery of the razorback sucker, information on hybrid viability is needed. We compared hatch success and larval survival of artificially spawned razorback sucker, flannelmouth sucker, and their hybrids. We were able to successfully spawn and rear all combinations, implying that there are limited pre- and postzygotic isolation mechanisms, and hybrids are likely to survive in the wild.

Arizona, Baja California, California, Colorado, Ne↗
USGS2020

Co-occurence of Chiricahua leopard frogs (Lithobates chiricahuensis) with sunfish (Lepomis)

Invasive species are a major threat to the persistence of native species, particularly in systems where ephemeral aquatic habitats have been replaced by permanent water and predators, such as fish, have been introduced. Within the Altar Valley, Arizona, the invasive American bullfrog, Lithobates catesbeianus (formerly Rana catesbeianus ), has been successfully eradicated to help recover Chiricahua leopard frogs ( Lithobates chiricahuensis ). However, other nonnative predators including sunfish ( Lepomis ) are present in some permanent water bodies. During four consecutive years (2014–2017), we detected both the federally threatened Chiricahua leopard frog and sunfish at one permanent water body in the Altar Valley. This suggests that despite the potential negative effect of predatory fish on amphibians, there may be conditions where the Chiricahua leopard frog can co-occur with this nonnative predator. A better understanding of rare situations of co-occurrence with nonnative predators may contribute to our understanding of why co-occurrence happens in some, but not all, systems and whether conservation strategies can be developed in situations where eradication of nonnative predators is infeasible.

Arizona↗
USGS2020

Reproduction and denning by San Clemente Island Foxes: Age, sex, and polygamy

Channel Island foxes ( Urocyon littoralis ) live on six of the eight California Channel Islands, and each island is inhabited by a distinct subspecies. Until recently, four of these subspecies were listed under the Endangered Species Act as endangered. Although three of the four subspecies have been delisted, and one subspecies was downlisted to threatened, all subspecies are still vulnerable because of small population sizes and potential threats from predation and disease. Consequently, information on reproductive behavior for each subspecies, including the San Clemente Island fox ( Urocyon littoralis clementae ), is important for understanding fox population dynamics. We determined reproductive status of 28 island foxes through observations of radio collared yearlings and adults with or without juveniles between 25 February and 8 October 2009. We found a greater number of adult foxes than yearling foxes and a greater number of female foxes than male foxes observed with juveniles. Also, there was a significantly greater probability of observing adult female foxes with juveniles than yearling males with juveniles. Only 1 of 28 radio collared foxes exhibited either polygamous or “helper” behaviors. Parturition started approximately 2 months earlier than historically recorded for other Channel Island fox subspecies. Our results suggest that in future studies of reproductive success more effort should be placed on monitoring adult females than yearling males. If emergence from dens continues to occur earlier than previously recorded, the current recommended time period for trapping (20 June–31 January) might need revision to exclude January to reduce stress to pregnant females. If all foxes have similar probabilities of transmitting disease on a given contact with juveniles, our data suggest that it may be appropriate to focus more vaccination efforts on females than males and adults than yearlings because they contact juveniles more frequently.

California↗
USGS2021

Augmentation of natural prey reduces cattle predation by puma (Puma concolor) and jaguar (Panthera onca) on a ranch in Sonora, Mexico

Retaliatory killing of large carnivores due to livestock predation is one of the major threats for the conservation of many declining populations of predators. According to empirical observations, there is a higher incidence of livestock predation when native prey abundance is low. In this study, we applied a treatment consisting of augmentation of prey abundance by translocation of peccaries ( Pecari tajacu ) and placement of four feed stations for white-tailed deer ( Odocoileus virginianus ) on a cattle ranch in Sonora, Mexico, with verified calf predation by puma ( Puma concolor ) and jaguar ( Panthera onca ). We quantified and compared consumed prey over two periods—phase I (8 months before the augmentation of prey) and phase II (8 months after the augmentation of prey)—through investigation of kill sites from Global Positioning System–collared jaguar and puma, prey identification from analyzed scat using molecular DNA techniques, and opportunistic discoveries of recently killed animal remains by either predator. We calculated the relative abundance of species (17 mammals [one species with two distinct age classes] and 1 bird species) through camera traps and for the most relevant prey species for this study (deer, calf, and peccary), we also estimated prey use by the predator, based on their availability during each period (prey preference). In the prey composition analyses of scat, we observed a significant reduction in the consumption of bovids and a significant increase in the consumption of peccaries during phase II. In the analyses of prey use, during phase I, predators consumed peccaries and calves at a higher proportion in relation to their availability. During phase II, consumption of calves declined from being preferred, to being consumed at the same proportion as their availability. Application of these results can contribute to the decrease of livestock predation and therefore conservation of pumas and jaguars.

Sonora↗
USGS2020

Lesser prairie-chicken (Tympanuchus pallidicinctus) use of man-made water sources

The lesser prairie-chicken ( Tympanuchus pallidicinctus ) occurs in the semiarid southern Great Plains, a region prone to periods of drought. Researchers generally believe that lesser prairie-chickens are able to satisfy their water requirements through preformed water and metabolic processes, but also know that they experience low survival and reproductive success during periods of drought. We used motion-sensing cameras to assess lesser prairie-chicken visits to man-made free water sources over a 48-month period from March 2009 to February 2013 in west Texas. Our objective was to examine temporal patterns of water use by lesser prairie-chickens, and to explore life history phenology and environmental conditions that may influence the species' use of free water. We documented 1,439 visits to water sources by lesser prairie-chickens. Their use of water sources was high during the winter months (December–February; 92 visits per 100 trap days) but the highest average visit rate to water sources occurred during the lekking-nesting life stage (March–May; 146 visits per 100 trap days). Water use was lower during the brood-rearing stage (June–August; 71 visits per 100 trap days) and lowest during the brood dispersal and independence stage (September–November; 19 visits per 100 trap days). Water use was strongly associated with dew point (P < 0.0001) and temperature (P = 0.0002) but was not associated with precipitation (P = 0.1037). These data indicate life-cycle stage (e.g., lekking-nesting) and reduced availability of preformed water may influence use of free water sources by lesser prairie-chickens. Current climate models predict the region of the study area will experience increases in temperature and decreases in frequency of precipitation. The combined effect of this would be reduced environmental moisture. If the prediction of increasing aridity in the region holds true, man-made water sources may become a tool for conservation of the species.

Texas↗
USGS2022

Use of regional breeding bird surveys to estimate bird populations in Big Thicket National Preserve

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.

Texas↗
USGS2022

Small-scale variation in trap placement affects arthropod capture rates on sticky traps in riparian woodlands

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.

The Southwestern Naturalist↗
USGS2022

Comparative assessment of laboratory-derived thermal maxima of Gila trout (oncorhynchus Gilae) with current stream temperatures

Gila trout ( Oncorhynchus gilae ) represent an iconic species of the American Southwest. The salmonid has survived extensive logging, livestock grazing, and mining, and is currently threatened by climate change, wildfire, and extended drought. Long-term conservation and recovery of the species and its unique lineages rely on stocking and translocation into historically inhabited streams. Thus, the fish's thermal tolerance is essential in determining suitable habitat and potential vulnerability to a warming climate. We compared a laboratory-derived temperature metric, critical thermal maximum (CTMax), in hatchery-reared Gila trout from three lineages (Main Diamond, South Diamond, and Whiskey Creek) to determine if CTMax differed among the lineages. The average initial (28.9°C, SD = 0.81°C) and final (29.2°C, SD = 0.74°C) temperature at loss of righting responses did not differ across the lineages. We compared the CTMax values with stream temperatures across three drainages representative of extant Gila trout populations from spring 2015 to fall 2018. The East Fork Gila River drainage was represented by more extreme stream temperatures. The maximum daily maximum temperature (i.e., single highest temperature) varied from 24.1 to 33.4°C, exceeding CTMax in four of the five streams. The maximum daily temperature varied from 12.1 to 28.6°C, and the mean weekly maximum temperature varied from 19.9 to 31.1°C. Mean weekly maximum temperature in Lower Diamond Creek exceeded CTMax on 11 occasions. Stream temperatures were cooler within the Middle and the West Fork Gila River drainages and did not exceed CTMax. Intermittency loggers within the East Fork Gila River drainage, which supports Main Diamond and South Diamond lineages of Gila trout, recorded over 300 days of intermittency during a drought. Continued long-term monitoring of stream temperature and comparison with CTMax of Gila trout could assist with decisions of which streams in the Gila Drainage are suitable for Gila trout recovery, stocking, and translocation.

New Mexico↗
USGS2023

Microhabitat use of native Santa Ana sucker and arroyo chub in an effluent-dominated southern California stream

A significant amount of the base flow of the Santa Ana River, located within California's arid Los Angeles metropolitan region, originates from two wastewater treatment facilities: the Rialto wastewater treatment facility and Rapid Infiltration and Extraction facility. The Santa Ana sucker ( Pantosteus santaanae , syn. Catostomus santaanae ) and arroyo chub ( Gila orcuttii ) are two native species listed in the Upper Santa Ana Habitat Conservation Plan, which aims to balance water supply needs with the ecological needs of native fauna. Consequently, an understanding of the habitat needs of these fishes will play a crucial role in achieving the goals outlined by the conservation plan. We used fish presence during snorkel surveys with habitat availability surveys to quantify habitat selection by both native fish species within a resource selection function analytical framework. We found that both species selected habitat near structures that could serve as refugia from potential predators. In addition, Santa Ana sucker selected habitats with high gravel and cobble substrate composition, presumably to fulfill complementary habitat needs such as foraging and spawning. Our results suggest that habitat alterations due to water management infrastructure and an increasing population size of nonnative predators may also affect native fish habitat selection in the Santa Ana River.

California↗
USGS2024

Diurnal habitat selection and survival of elk neonates

Natural selection should favor development of behaviors that increase survival, including juvenile survival. Habitat characteristics (e.g., hiding cover, forage quality and availability), maternal habitat selection, and microhabitat selection by the calf may influence elk ( Cervus canadensis ) calf survival and recruitment. We assessed diurnal microhabitat selection of bed sites by elk calves and calf-rearing areas selected by adult females to determine if these characteristics were associated with calf survival. We radio-tagged 33 elk calves in west-central New Mexico in 2011 and 55 calves in north-central New Mexico in 2012. We tracked calves daily to locate calf bedding sites and collected data on selected physical features and vegetation characteristics at used and paired random sites. The paired differences in these characteristics were then associated with calf fate. At the calf selection scale, for every 1-m difference in the distance to nearest concealment cover, the odds that a site was from a surviving calf increased by 7.8%. Habitat selection by adult females also was associated with calf survival. The odds of a bed site being from a surviving calf increased by 1.9% for every 1% difference in percentage of grass cover. High levels of concealment cover at the bed site were related to calf survival status. When we expanded selection to the adult level, females with surviving calves selected areas with higher grass cover, suggesting adult selection for higher forage availability while still providing high concealment cover for the calf.

Southwestern Naturalist↗
USGS2024

Analysis of mitochondrial DNA sequence data demonstrates that monophyly of myotis occultus is complicated by greater sampling of myotis lucifugus

The validity of Myotis occultus as a species unique from Myotis lucifugus has been a source of debate. Most recently, many authorities treat M. occultus as a distinct species, at least in part because a previous study showed that M. occultus and M. l. carissima (the subspecies that occurs in closest geographic proximity to M. occultus ) form separate monophyletic clades based on sequences of two mitochondrial genes (cytochrome- b [cytb] and cytochrome oxidase subunit II [COII]). We re-evaluated the phylogenetic relationship between M. occultus and M. lucifugus based on mitochondrial sequences using an expanded dataset of cytb and COII sequences that originated from more genetically diverse specimens of M. lucifugus collected across a broader geographic area. Based on a phylogenetic analysis, we found that M. occultus sublineages embedded within a well-supported clade that included some specimens of M. lucifugus . These results indicate that the previous genetic analysis demonstrating that M. occultus and M. lucifugus form distinct monophyletic groups is unsupported by our larger dataset. Future research will likely need to focus on genetic work involving whole-genome sequencing of nuclear DNA to better resolve the true taxonomic relationship between M. occultus and M. lucifugus . La valides de Myotis occultus como una especie distinta a Myotis lucifugus ha sido fuente de debate. Recientemente, muchas autoridades han considerado M. occultus como una especie diferente, en parte porque un estudio anterior mostró que M. occultus y M. l. carissima (la subespecie con la mayor proximidad geográfica a M. occultus) forman clados monofiléticos separados basados en secuencias de dos genes mitocondriales (el citocromo-b [cytb] y la subunidad II de citocromo oxidasa [COII]). Nosotros hemos reevaluado la relación filogenética entre M. occultus y M. lucifugus usando una ampliada colección de datos que contiene secuencias de los genes mitocondriales cytb y COII de especímenes de M. lucifugus genéticamente más diversos que fueron muestreados en un área geográfica más extensa. Nuestro análisis filogenético muestra que los sublinajes de M. occultus están incrustados dentro de un clado bien respaldado que incluye algunos especímenes de M. lucifugus. Estos resultados indican que el análisis genético anterior que demostró que M. occultus y M. lucifugus forman grupos monofiléticos distintos no está respaldado por nuestra más amplia colección de datos. Es probable que para resolver mejor la verdadera relación taxonómica entre M. occultus y M. lucifugus sea necesario el uso de secuenciación del genoma completo del ADN nuclear.

Southwestern Naturalist↗
USGS2024

Gulf killifish (Fundulus grandis) in the Pecos River: Unique life history traits in a nonnative, island population

Nonnative species may display unique life history traits when established in habitats with distinctive environmental and biotic contexts compared with their native ecosystems. Gulf killifish ( Fundulus grandis ), native to coastal habitats of the Gulf of Mexico, are established in several inland river systems where they pose a potential threat to native fishes. In the Pecos River, Texas, nonnative Gulf killifish have shown a high rate of piscivory compared with native coastal populations; otherwise, little is known about the ecology of the species in inland systems. We examined reproductive characteristics, size, and age of Gulf killifish in the Pecos River. We found that reproduction takes place approximately between late March and September, with the gonadosomatic index of females showing a large and extended peak in spring and a second minor peak in late August–September. Our age estimations indicate that this population consists mostly of fish <2 years old, similarly to that reported for coastal populations. Total length ranged 11.9–143.4 mm for males and 32.3–162.5 mm for females, indicating a sexually dimorphic size structure with Pecos River individuals reaching larger sizes compared with coastal populations. The relatively large size and piscivorous nature of Gulf killifish, along with tolerance for a wide range of environmental conditions, are attributes in nonnative species hypothesized to promote invasion success and replacement of native species.

New Mexico, Texas↗
USGS2025

Serological assessment of pathogen exposure among desert bighorn sheep in southwestern Arizona

Bighorn sheep ( Ovis canadensis ) are influenced by infectious diseases. Although Mycoplasma ovipneumoniae has been the main focus of bighorn sheep managers since early 2010, other pathogens may also influence bighorn sheep populations. We sampled desert bighorn sheep ( Ovis canadensis mexicana ) captured for a study on the Cabeza Prieta National Wildlife Refuge in southwestern Arizona, USA, 2001–2005, for a suite of pathogens: bluetongue (BT), epizootic hemorrhagic disease (EHD), parainfluenza 3, bovine respiratory syncytial virus, Clamydia , seven Leptospira serovars, bovine herpesvirus 1 (causative agent of infectious bovine rhinotracheitis), bovine viral diarrhea virus, and bovine respiratory syncytial virus. We recorded evidence of exposure to seven of these pathogens, with two Leptospira serovars ( hardjo and bratislava ), five strains of BT, and two strains of EHD detected. Seroprevalence rates of detected pathogens varied between 12–49%. We observed high levels of co-occurrence for EHD and BT. These results highlight that multiple pathogens may influence desert bighorn sheep populations. These data also provide historical context to pathogen exposure for a region where few such data are available.

Arizona↗