We used Multispatial Convergent Cross Mapping analysis to detect causality on monthly differences of zooplankton volume and fish density and biomass time-series of atherinopsids (Chirostoma species) and barred splitfin (Chapalichthys encaustus) from Lake Chapala, Mexico. The dynamics of monthly differences of zooplankton volume were causally influenced by monthly differences in pH. The dynamics of the monthly differences of atherinopsid and barred splitfin density, and atherinopsid biomass, were not causally influenced by monthly differences of any of the measured physicochemical variables. The dynamics of the monthly differences of the barred splitfin biomass were due to monthly differences in water temperature and alkalinity. The dynamics of monthly differences of zooplankton volume did not show any significant causal forcing on the dynamics of monthly differences of density and biomass of atherinopsid and barred splitfin density. The dynamics of monthly differences of atherinopsids showed significant causal influence on the dynamics of the monthly differences of the barred splitfin, but barred splitfin did not show causal influence on the dynamics of the monthly differences of atherinopsids.

I compared riparian cottonwood (Populus fremontii) productivity-discharge relationships in a relictual stand along the highly regulated Green River and in a naturally functioning stand along the unregulated Yampa River in semiarid northwest Colorado. I used multiple regression to model flow effects on annual basal area increment (BAI) from 1982 to 2011, after removing any autocorrelation present. Each BAI series was developed from 20 trees whose mean size (67 cm diameter at breast height [DBH]) was equivalent in the two stands. BAI was larger in the Yampa River stand except in 2 y when defoliating leaf beetles were present there. I found no evidence for a Yampa flood-magnitude threshold above which BAI declined. Flow variables explained ∼45% of residual BAI variability, with most explained by current-year maximum 90-d discharge (Q_M90) in the Yampa River stand and by a measure of the year-to-year change in Q_M90 in the Green River stand. The latter reflects a management-imposed ceiling on flood magnitude—Flaming Gorge Dam power plant capacity—infrequently exceeded during the study period. BAI in the relictual stand began to trend upward in 1992 when flows started to mimic a natural flow regime. Mature Fremont cottonwoods appear to be ecologically resilient. Their productivity along regulated rivers might be optimized using multiyear environmental flow designs.

Availability and habitat use are central factors in the selection of prey by mountain lions (Puma concolor), and they are important for understanding predator–prey dynamics. We used an array of camera traps to evaluate the relative abundance and spatial distribution of mountain lions and their prey in the Davis Mountains of Texas. Resource selection was evaluated for four criteria: elevation, ecological system, fine-scale terrain ruggedness, and broad-scale terrain ruggedness. We used χ² analysis to determine whether habitat was used in proportion to availability, and then we calculated a selection index with 95% confidence intervals using a Bonferroni adjustment. We found feral hog (Sus scrofa) to be the most abundant species, composing 23% of the total animals observed. Feral hog and gray fox (Urocyon cinereoargenteus) were the most widespread species, each observed at 33 of 38 camera locations. For each prey species evaluated, habitat use differed significantly from availability for at least one of the four resource criteria. Mountain lion use of resource criteria was not different from availability, except they avoided the second lowest class of broad-scale terrain ruggedness. With knowledge of mountain lion habitat use and the availability of prey, resource managers can better assess what effects mountain lion predation may have on a specific species, thereby allowing for better management of those species.

We report on the natural history of Ambystoma altamirani from the Arroyo Los Axolotes, State of Mexico. Ambystoma altamirani used stream sites that hold a greater volume of water, higher dissolved oxygen levels, and faster moving water compared with those without A. altamirani. They used sites with grassy vegetation, and mud and sandy substrate. Males were larger than females. We observed three egg masses in June 2015 (mean = 21 eggs). Metamorphosis occurred between 62 and 70 mm snout–vent length. Our results indicate that Arroyo Los Axolotes must be managed to maintain conditions and water flow amenable to the persistence of A. altamirani.

We compared abundance and activity patterns of medium-sized felids in the neotropics. We used 29 camera traps to record species in the region of Los Chimalapas, Oaxaca, Mexico, during 2011–2013. We estimated population size with the capture-recapture model (Cormack-Jolly-Seber model). We assessed the differences in activity patterns between species through the Mardia-Watson-Wheeler test. Leopardus pardalis, Leopardus wiedii, and Puma yagouaroundi were recorded by cameras. The population size of L. wiedii was high in comparison with L. pardalis, which presented a medium abundance compared to other regions. Puma yagouaroundi individuals were relatively rare, likely due to a difference in habitat selection. We provide evidence that in the southeastern region of Mexico there is a significant L. wiedii population despite the presence of L. pardalis.

We report on a survey of the small mammal communities of Anaho Island and the mainland surrounding Pyramid Lake in the Great Basin of western Nevada. Ten rodent species were detected on the mainland, but only the deer mouse (Peromyscus maniculatus) was detected on Anaho Island. Although the mean abundance of deer mice on the Pyramid Lake mainland was more than double that of Anaho Island (12.5 ± 10.1 individuals per trap grid compared with 5.0 ± 3.4 individuals per trap grid), we did not detect a significant difference between locations. Deer mice on Anaho Island were significantly larger in body size (mean body length = 86 ± 4 mm) than mainland mice (mean = 75 ± 7 mm), but it is unclear what mechanisms might have produced the observed divergence in body size.

Dynamic factor analysis was used to discern underlying common trends and the effect of physicochemical variables on time series of zooplankton, fish density, and biomass of barred splitfin (Chapalichthys encaustus) and atherinopsids (Chirostoma spp.) from Lake Chapala, Mexico. Strongly coherent trends were identified for the zooplankton and atherinopsid time series. Weakly coherent trends were detected for the barred splitfin time series.

We assessed zebra mussel (Dreissena polymorpha) distribution and density in four newly infested manmade reservoirs in the upper Neosho River Basin, Kansas, from March–November 2011. Density was estimated via monthly plankton samples to monitor veligers, visual searches to detect recruited zebra mussels, and colonization substrates to monitor settling zebra mussels. Infested impoundments upstream were likely the source of zebra mussels dispersing into downstream impoundments in the basin. Marion Reservoir had greater veliger densities downlake than in its upper region while veliger densities in the other three reservoirs were not significantly different among lake regions. Veliger and adult densities were less in the outlet downstream from Marion Reservoir than in the downlake portion of the reservoir. Differences among reservoirs could reflect differences in time since infestation as well as variability in temperature and local physicochemical factors.

In transcribing one of the few remaining John James Audubon journals in 1929, Corning reported that Audubon heard “Iowa Buntings” in eastern Arkansas in mid-December of 1820. This reference has been copied repeatedly since then, and some have speculated as to what an “Iowa Bunting” might refer. Examination of the original journal, however, revealed that he was referring to the “Towe Bunting” or eastern towhee (Pipilo erythrophthalmus).

We described the chemical transition that takes place in the fruits and seeds of laurel cherry (Prunus caroliniana), an evergreen tree native to the subtropical United States with bird-dispersed seeds. The unripe fruits contain cyanide and release it when the fruit tissue is damaged, whereas ripe fruits are cyanide free. The reverse was true for seeds: immature seeds were free of cyanide whereas mature seeds were cyanogenic. We also described the reproductive phenology of laurel cherry and suggest that the chemical trait we described protects the fruits during their unusually long maturation period.

We documented four razorback sucker (Xyrauchen texanus) individuals originally stocked in the San Juan River, New Mexico, subsequently recaptured in the Colorado and Green rivers, Utah. Each fish moved >550 km between stocking and recapture locations. The time between detections was 171–1,519 days. These movements included ≥210 km through Lake Powell. Lake Powell was previously thought to be a barrier between razorback sucker populations in the San Juan River and the Colorado and Green rivers.

Incidences of atypical color patterns in otters are scarce, particularly for the Neotropical otter (Lontra longicaudis annectens). We report three L. l. annectens individuals, one with partial and two with total leucism; the first otter is from Río Temascaltepec, state of México, and the other two otters are from Mante, Tamaulipas, México. Because causes that induce this genetic alteration are poorly understood, possible factors that might induce this phenotypic abnormality and the adverse effects on Neotropical otter populations are discussed.

We document the conchas crayfish (Orconectes deanae) as another introduced crayfish in the middle Rio Grande. We collected O. deanae in the Rio Grande and its associated ditches between Belen and La Joya, New Mexico. We did not collect O. deanae from the adjacent Pecos River; further sampling is necessary to determine the full range and impact of this alien species in the Rio Grande drainage.

During late summer and fall 2014, we documented western pond turtle (Actinemys marmorata) mortality, as indicated by the presence of turtle shells, along a 3.7-km reach of Coyote Creek in the Diablo Range of central California. In total, we observed 39 western pond turtle shells scattered irregularly along our study reach. Shells were found in dry reaches adjacent to or close to pools containing live turtles, as well as in or adjacent to dry pools in isolated dry reaches. Ninety percent of shells observed contained no carcass, and several shells showed evidence of predation. Though the cause of mortality is unclear, our observations confirm that western pond turtles may experience high mortality during droughts, which could result in significant population decline. The presence of live turtles in refugial pools emphasizes the importance of protecting and managing permanent pools in the face of intensified drought conditions.

Gulf killifish, Fundulus grandis, have been introduced in the Lower Pecos River and are highly abundant in reaches of the Permian Basin region. Very little is known about the ecology of nonnative, inland populations of F. grandis. We investigated the feeding ecology of this species in the Pecos River using stomach contents analysis and laboratory feeding trials. Inland F. grandis were piscivorous, consuming more fish prey than has been reported from native coastal ecosystems. Predation by F. grandis could threaten native species in the Pecos River and other inland systems where it has been introduced.

We report the occurrence of the terrestrial isopod Miktoniscus medcofi from a fen in Real County, Texas, representing a new state record for the species as well as a western range extension for the genus. Morphologic characteristics closely conform to the species description and distinguish the Texas population from congeners. Miktoniscus medcofi ranges from New York to Texas and south to Veracruz, Mexico, but may represent multiple cryptic species or a species complex.

Insects possess several physiological and morphological adaptations to high temperatures; in particular, critical thermal maxima may be of increasing importance as climates warm. We sought to determine the relationship between critical thermal maxima and body size in red imported fire ants, Solenopsis invicta. Thermal maxima were measured and regressed against body mass, tibial length, head width including the eyes, and total body length in individuals from 35 fire ant colonies within and around Lubbock, Texas. Major and media workers survived higher temperatures more often than did minor workers. This may relate to surface-area-to-volume ratios, higher desiccation resistance in larger workers, or both; however, further studies are needed to confirm this. These results suggest that body size may be an important predictor of thermal performance for ectotherms.

We present evidence for the overlap of two species of clingfishes, mountain clingfish (Gobiesox fluviatilis) and Mexican clingfish (Gobiesox mexicanus), in the Cuitzmala River, state of Jalisco, western Mexico. In addition to documenting novel sites where these species can be found, we present a new maximum standard length for G. fluviatilis, 137.8 mm. Morphometric and meristic variation in diagnostic characters for these species is higher than previously reported. We recommend a revision of diagnostic characters for Mexican freshwater clingfishes to better understand the systematics and distribution of species in the group.