Western North America

Population declines due to chytridiomycosis among frogs belonging to the Amerana (Rana boylii) species group from western North America have been particularly severe. Norepinephrine-stimulated skin secretions from the Oregon spotted frog Rana pretiosa Baird and Girard, 1853 were collected from individuals that had been previously infected with the causative agent Batrachochytrium dendrobatidis but had proved resistant to developing chytridiomycosis. These secretions contained a more diverse array of antimicrobial peptides than found in other species from the Amerana group and 14 peptides were isolated in pure form. Determination of their primary structures identified the peptides as esculentin-2PRa and -2PRb; ranatuerin-2PRa, -2PRb, -2PRc, -2PRd, and -2PRe; brevinin-1PRa, -1PRb, -1PRc, and -1PRd; and temporin-PRa, -PRb, and -PRc. The strongly cationic ranatuerin-2PRd and the esculentin-2 peptides, which have not been identified in the secretions of other Amerana species except for the closely related R. luteiventris, showed the highest growth inhibitory potency against microorganisms. The strongly hydrophobic brevinin-1PRd was the most cytotoxic to erythrocytes. Although no clear correlation exists between production of dermal antimicrobial peptides by a species and its resistance to fatal chytridiomycosis, the diversity of these peptides in R. pretiosa may be pivotal in defending the species against environmental pathogens such as B. dendrobatidis.

In western North America, Rocky Mountain national parks represent a major resource for nature-based tourism. This paper examines how climate change may influence park tourism in the Rocky Mountain region by focusing on both the direct and indirect impacts of climate change for visitation to Waterton Lakes National Park (WLNP) (Alberta, Canada). A statistical model of monthly visitation and climate was developed to examine the direct impact of climate change on visitation. The model projected that annual visitation would increase between 6% and 10% in the 2020s and between 10% and 36% in the 2050s. To explore how climate-induced environmental change could also indirectly affect visitation, a visitor survey was used (N=425N=425). The environmental change scenarios for the 2020s and 2050s were found to have minimal influence on visitation, however the environmental change scenario for the 2080s (under the warmest climate change conditions) was found to have a negative effect on visitation, as 19% of respondents indicated they would not visit the park and 37% stated they would visit the park less often. The contrasting result of the two analyses for the longer-term impact of climate change was a key finding. The management implications of these findings and methodological challenges associate with climate change impact assessment for tourism are also discussed.

The voluminous Meso- to Neoarchean rocks exposed in the Beartooth Mountains of the northern Wyoming Province of western North America comprise the Long Lake Magmatic Complex (LLMC), a variably metamorphosed and deformed association of igneous and meta-igneous plutonic rocks with SiO2 ranging from at least 52 to 78 wt%. Within this compositional range, rock types include lineated amphibolites to hornblende-bearing gneisses of intermediate composition and multiple generations of foliated to unfoliated granitoids. Emplacement ages range between approximately 2.79 and 2.83 Ga, based on U–Pb zircon geochronology (SHRIMP). Field relations, elemental compositions, and geochronology indicate that these rocks do not represent a single fractional crystallization sequence, but rather, the LLMC was constructed by injection of numerous, discrete magmas as sill-like bodies over an ∼40 Ma period. Although there is a continuum of compositions in the LLMC, trace element abundances can be used to distinguish distinct sources and petrogenetic processes that can be broadly extrapolated to at least 3 compositional groupings: (1) trondhjemitic to granitic intrusive rocks with SiO2 >70 wt%, (2) variably metamorphosed granodioritic orthogneisses with SiO2 between 63 and 70 wt%, and (3) amphibole-bearing mafic to intermediate gneisses with SiO2 between 52 and 63 wt%. Despite the range of SiO2 contents, maximum LREE abundances are similar across the compositional range and, consequently, exhibit a wide range of (La/Yb)n ratios (∼20–130). All LLMC rocks share a relative depletion in HFSE abundances similar to modern convergent margin magmas. Initial Sr and Nd isotopic compositions across the compositional range are consistently offset from typical bulk silicate earth (BSE) values and preclude unaltered derivation from primitive or depleted mantle. Common Pb isotopic data define a single array that lies above model crustal growth curves and, along with the Nd and Sr data, suggest relatively uniform interaction with, or derivation from, older lithosphere. The combined isotopic and elemental data suggest the LLMC resulted from simultaneous, rapid, and voluminous production of diverse magmas that represent melting of isotopically similar, but compositionally distinct, crustal and mantle sources. Dynamically, Meso- to Neo-archean crustal growth in the northern Wyoming Province appears to require an environment similar to a modern ocean–continent convergent margin with a comparable rate of crustal production and diversity of magma series. The resultant crust and associated mantle lithosphere (keel) appear to have suffered little-to-no modification prior to Laramide (Cretaceous) uplift and exposure.

Through tabular and average linkage cluster analyses, 737 phytosociological relevés were classified. Based on these relevés, we described and typified the associations, alliances, orders, and classes grouping the coastal plant communities of the Baja California peninsula. Diagnostic tables, classification by average linkage clustering, and climatic, edaphic, and biogeographical data were used to establish floristic affinities among these syntaxa and to interpret their distributions. Syntaxa were characterized by their floristic composition, physiognomy, and biogeographical distribution, along with their positions in halophilous and psammophilous gradients. Thirty-three associations were identified, of which 22 are here described for the first time. Our syntaxonomical proposal includes descriptions of nine new alliances, seven new orders and four new classes: Allenrolfeetea occidentalis, Atriplici julaceae–Frankenietea palmeri, Euphorbio leucophyllae–Sporoboletea virginici and Achyronichio cooperi–Abronietea villosae.

RESUMEN En el noreste de México se han reportado algunos afloramientos de rocas volcánicas Triásicas y Jurásicas, cuyas características petrológicas y geoquímicas demuestran una afinidad de arco que permite relacionarlas a una margen continental activa. Más elementos que ...

Based on the analysis of 249 museum-preserved specimens, together with data on captive individu-als, the present paper provides information on the diet, morphology, and reproduction of the glass lizard Ophiodes cf. striatus in the subtropical domain, permitting comparisons with previous reports from different localities. This species is a generalist predator feeding on a wide variety of invertebrate taxa. In addition, O. cf. striatus occasionally preys on reptiles, including conspecific individuals. There is no evidence of partition-ing of prey types between the sexes or ontogenetic changes. In our study, Aranae was the most important food item in the diet, closely followed by Orthoptera. The total volume of prey, but not the number of prey items in each stomach, was positively correlated with lizard snout-vent length (SVL). Females had greater SVL, whereas males had longer tails and vestigial hind limbs. Female oviductal embryos were recorded be-tween July and December, and parturi...

Abstract. The present paper contains the results of a 7 year faunistical study upon the amphibian and reptile species from the Bistriţa river basin. We recorded 14 species of amphibians (Salamandra salamandra, Triturus cristatus, Lissotriton vulgaris, Lissotriton montandoni, Mesotriton alpestris, Bombina bombina, Bombina variegata, Hyla arborea, Rana dalmatina, Rana temporaria, Pelophylax ridibundus, Bufo bufo, Bufo viridis, Pelobates fuscus), 3 types of hybrids between amphibians (L. vulgaris X L. montandoni, Pelophylax ...

Insects are important forest disturbance agents, and mapping their effects on tree mortality and surface fuels represents a critical research challenge. Although various remote sensing approaches have been developed to monitor insect impacts, most studies have focused on single insect agents or single locations and have not related observed changes to ground-based measurements. This study presents a remote sensing framework to (1) characterize spectral trajectories associated with insect activity of varying duration and severity and (2) relate those trajectories to ground-based measurements of tree mortality and surface fuels in the Cascade Range, Oregon, USA. We leverage a Landsat time series change detection algorithm (LandTrendr), annual forest health aerial detection surveys (ADS), and field measurements to investigate two study landscapes broadly applicable to conifer forests and dominant insect agents of western North America. We distributed 38 plots across multiple forest types (ranging from mesic mixed-conifer to xeric lodgepole pine) and insect agents (defoliator [western spruce budworm] and bark beetle [mountain pine beetle]). Insect effects were evident in the Landsat time series as combinations of both short- and long-duration changes in the Normalized Burn Ratio spectral index. Western spruce budworm trajectories appeared to show a consistent temporal evolution of long-duration spectral decline (loss of vegetation) followed by recovery, whereas mountain pine beetle plots exhibited both short- and long-duration spectral declines and variable recovery rates. Although temporally variable, insect-affected stands generally conformed to four spectral trajectories: short-duration decline then recovery, short- then long-duration decline, long-duration decline, long-duration decline then recovery. When comparing remote sensing data with field measurements of insect impacts, we found that spectral changes were related to cover-based estimates (tree basal area mortality [R2adj=0.40, F1,34=24.76, P<0.0001] and down coarse woody detritus [R2adj=0.29, F1,32=14.72, P=0.0006]). In contrast, ADS changes were related to count-based estimates (e.g., ADS mortality from mountain pine beetle positively correlated with ground-based counts [R2adj=0.37, F1,22=14.71, P=0.0009]). Fine woody detritus and forest floor depth were not well correlated with Landsat- or aerial survey-based change metrics. By characterizing several distinct temporal manifestations of insect activity in conifer forests, this study demonstrates the utility of insect mapping methods that capture a wide range of spectral trajectories. This study also confirms the key role that satellite imagery can play in understanding the interactions among insects, fuels, and wildfire.