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Published accounts describe the eggs of spotted frogs (Rana luteiventris and Rana pretiosa) as having either 1 or 2 jelly envelopes surrounding the ovum. Eggs of R. luteiventris are typically reported to have a single jelly envelope, whereas those of R. pretiosa are reported to have 2 envelopes. We found, however, that both species' eggs actually have 3 jelly envelopes. In this paper we describe the eggs of both species, and identify the origin of the discrepancy in the scientific literature.
North American Porcupines (Erethizon dorsatum) have a broad geographic distribution across much of the continent, but recent evidence suggests that their populations may be declining in some areas, including the Pacific Northwest. Estimating baseline historical and contemporary distributions of Porcupines is necessary for initiating monitoring efforts and, if necessary, informing strategic conservation actions. We compiled 1905 occurrence records of Porcupines in Washington, Oregon, and northern California from 1908 to 2018. Using maximum entropy modeling (Maxent), we created historical and contemporary distribution models based on Porcupine records from 1981–2010 and 2012–2018, respectively, to match the temporal scale of available environmental predictor layers and suspected onset of the decline. Our models suggested a recent shift in the occupied environmental niche of Porcupines in the Pacific Northwest away from forested areas and towards desert scrub and grassland vegetation communities. In addition, we tested a non-invasive survey method for determining Porcupine presence and monitoring their status over time. Our trials suggested that sodium-soaked wood blocks may provide an inexpensive and minimally invasive technique to detect Porcupines, but further testing is needed to understand its effectiveness and limitations.
Montane meadows are areas of high biodiversity and provide many important ecosystem services; however, degradation of 40–60% of these habitats in the Sierra Nevada region of California has left many of these areas impaired. The “pond-and-plug” meadow-restoration technique is 1 type of treatment implemented to restore montane meadows. The objectives of this technique are to re-water the meadow and promote downstream flow by increasing the water-table elevation and providing additional water storage that will promote the growth of mesic and hydric vegetation that maintains and stabilizes stream channels. However, aquatic habitat and the composition and functioning of aquatic communities in these systems post-treatment are poorly documented or understood. We evaluated: (1) fish habitat, community composition, and relative abundance among recently created ponds spanning the range of pond habitats; (2) seasonal movement and survival of fish within and among ponds; and (3) food web structure in ponds. We documented over-summer and winter survival in the fish community and short-distance movement by 1 species occupying the ponds. Mark-recapture data suggest that all fish species present are capable of surviving both summer and winter conditions when pond conditions could be most limiting. Food web structure among intensively sampled ponds was similar, with overlapping isotopic niche width for dominant taxa. However, basal resource diversity (BRD) varied among ponds, with those having higher macrophyte cover also showing greater BRD. Our findings suggest that pond-and-plug techniques can provide habitat for native fishes that are able to tolerate departures from the species thermal and dissolved oxygen optima. Future meadow treatments could benefit from short-term restoration techniques such as pond-and-plug to allow for longer-term processes to influence meadow condition over time.
The historical distribution of Fishers throughout Montana and the northern Rocky Mountains of the United States is poorly understood, and most Fishers in Montana appear to be descendants of translocated animals originating from the midwestern United States and British Columbia; however, a genotype that is unique and native to the Northern Rockies of Idaho and Montana exists in west-central Montana. Predictions based on Idaho models depict potential suitable habitat for Fishers throughout the Cabinet Mountains of northwestern Montana, yet distribution, occupancy, and population status is currently unknown for these Fishers. We conducted the 1st comprehensive monitoring of Fishers in the Cabinet Mountains of Montana using baited camera/DNA stations. We detected Fishers at 7 out of 21 cells, which resulted in a 0.43 probability that Fishers occupied a grid cell. Detection probability was low. Genetic analysis revealed a minimum population count of at least 4 individual Fishers in the study area, but all individuals successfully identified were males and of midwestern genetic origin. The low number of Fisher detections may indeed reflect low abundance of Fisher. We recommend future multi-season monitoring over a longer period to increase precision of occupancy estimates, and additional research is needed to evaluate the lack of female detections. We also recommend maintaining a closed trapping season on Fishers, until data exist to document a population large enough to sustain harvest.
Conboy Lake National Wildlife Refuge (CLNWR) in Washington State supports one of the largest remaining populations of federally listed Oregon Spotted Frogs (OSF; Rana pretiosa). Invasive American Bullfrogs (Lithobates catesbeianus [Rana catesbeiana]), implicated in amphibian declines, are also abundant at CLNWR. Owing to the likely negative effect of this aquatic invader on the highly aquatic OSF, bullfrog control strategies are needed. One method is to limit habitat used by bullfrogs while retaining or enhancing OSF habitat, but for such an approach to be implemented, the 2 species must partition habitat sufficiently. We used radiotelemetry to characterize OSF and bullfrog active-season and pre-overwintering habitat in the human-engineered ditch system at CLNWR. We tracked 12 OSF and 10 bullfrogs from mid-to-late summer, recorded data on frog location and habitat, and analyzed movement patterns, niche breadth, and spatial differences between species. Based on minimum convex polygons, bullfrogs overlapped extensively with OSF habitat space in the ditch system. During the active season, niche analyses also showed extensive overlap in the species' vegetation associations, with selected exceptions at the microhabitat scale. However, each species used distinct pre-overwintering habitats. The small differences in active-season microhabitats and pre-overwintering habitats, and our relatively narrow study conditions, create uncertainty about these species' habitat use in a broader context. Nonetheless, these results underscore the challenge of managing an invasive species that is both a habitat generalist and congener and expose the need for further research to guide management approaches to favor OSFs at CLNWR.
Point counts of wintering land birds using Russian Olive (Elaeagnus angustifolia) stands were conducted in 2000 and 2005 on the Snake River Plain, Idaho. The 14 most common species of the 28 recorded were found in both years, and most common species were recorded with similar frequencies between years. Thirteen bird species were observed foraging on Russian Olive fruits. Increases in recent decades in both area occupied by Russian Olive and in counts of Yellow-rumped Warblers (Setophaga coronata) and American Robins (Turdus migratorius) on Christmas Bird Counts suggest that there may be a relationship between Russian Olive expansion and abundance of these species.
Established in 1907, Jasper National Park (JNP) comprises 10,880 km2 of mountainous terrain in western Alberta, Canada. Its large mammals have been protected from hunting and trapping, but are subject to accidental collisions with vehicles and trains on the Yellowhead Highway and the Canadian National Railway (CNR) that transect JNP. This paper reviews the park's historical inventory of Elk (Cervus elaphus), Bighorn Sheep (Ovis Canadensis), and Gray Wolves (Canis lupus), and reports on their number killed by vehicles and trains from 1980 to 2018. Elk population estimates declined from 1000 in 1975 to 318 in 2018. An aerial survey of Bighorn Sheep flown in 2018 over all of JNPs sheep range recorded a decline of 58–62% compared to 1987. In the lower main valley, discrete bands of rams and ewes declined on 2 traditional winter ranges. The road and rail fatalities of Elk and sheep were superimposed on predation. In the late 1970s, wolves were estimated at 160, but reached an undetermined low in 2018 following year-round trapping on JNPs boundaries and accidental fatalities on the park's roads and railways.
Western Toads (Anaxyrus boreas) are widely considered to be of conservation concern, and have high genetic variability both continentally and locally. Previous research has identified 3 major genetic clades of Western Toads in North America. We collected tissue samples from 47 larval toads representing 16 different collection sites in northern Idaho and northeastern Washington. For each sample we sequenced a 269 base-pair section of the mitochondrial cytochrome c oxidose I (COI) gene. We also downloaded COI sequences from GenBank, which had been used in a previous study to identify geographic clades. We used PAUP to build phylogenies in which our samples did not align geographically with each other or form distinct clades within the continental phylogeny. Our samples did, however, group in the expected Northwestern clade which was identified in a previous study. The toads examined in our study area show no evidence of cryptic diversity within the section of COI we examined and our data support the current taxonomic assignment to Anaxyrus boreas.
We conducted a pilot study assessing the role that Orange-crowned Warblers (Oreothlypis celata) may play in the pollination of Vine Maple (Acer circinatum). We observed an Orange-crowned Warbler probing its head into different inflorescences between 2 focal trees. We also incidentally observed O. celata individuals foraging in Big-leaf Maple (Acer macrophyllum) inflorescences and a Wilson's Warbler (Cardellina pusilla) feeding in the flowers of a Vine Maple. Our observations and results from the pilot experiment excluding large-bodied pollinators from flowers lead us to suggest that warblers may forage at Vine Maple flowers in a manner that could contribute to pollination; however, further study to confirm that warblers transfer pollen from anthers to conspecific stigmas is warranted.
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