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Made available in DSpace on 2022-04-28T19:52:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-03-18 Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale. Department of Biology University of Toronto Mississauga ON Centre for Urban Environments University of Toronto Mississauga ON Department of Biology University of North Carolina, Chapel Hill Department of Biology University of Louisiana LA Department of Biology Queen's University ON Department of Biology Concordia University QC Department of Biological Sciences DePaul University Department of Biology DePauw University IN Department of Urban Design and Planning, University of Washington, Seattle, WA, USA Colegio de Ciencias Biológicas y Ambientales Universidad San Francisco de Quito USFQ Department of Genetics University of Georgia Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University Field Science Center for Northern Biosphere Hokkaido University Natural History Museum Zoology University of New England NSW Programa de Pós-Graduação em Geografia da UFMT campus de Rondonópolis Department of Botany and Biodiversity Research Centre University of British Columbia Graduate Program in Genome Sciences and Technology Genome Sciences Centre University of British Columbia Department of Microbiology and Immunology University of British Columbia Red de Biología Evolutiva Instituto de Ecología A. C. School of the Environment Yale University CT Departamento de Ciencias Ecológicas Universidad de Chile, Facultad de Ciencias Instituto de Ecología y Biodiversidad Universidad de Chile Department of Biology Mount Allison University Red de Ecoetología Instituto de Ecología A. C. Department of Biology University of Ottawa ON Department of Zoology University of Cambridge Department of Biology, Washington University in St. Louis, St. Louis, MO, USA Department of Biology University of Miami FL Centro de Investigación en Recursos Naturales y Sustentabilidad (CIRENYS) Universidad Bernardo O'Higgins Department of Biology, University of La Verne, La Verne, CA, USA Département des sciences du bois et de la forêt Université Laval QC Evolution & Ecology Research Centre School of Biological Earth and Environmental Sciences UNSW Sydney NSW Department of Biology Ghent University Department of Biology Monmouth University West Long Branch Centre for Ecology Evolution and Environmental Changes Faculdade de Ciências Universidade de Lisboa Lisboa Department of Biology KU Leuven School of Agriculture and Environment Wildlife and Ecology group Massey University, Palmerston North Department of Biological Sciences University of Cape Town Institute of Landscape Ecology University of Münster Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY, USA Department of Biological Sciences University of Alberta AB Louis Calder Center and Department of Biological Sciences, Fordham University, Armonk, NY, USA Departamento de Ecología Tropical, Universidad Autónoma de Yucatán, Mérida, Yucatán, México School of Life Sciences University of Sussex Department of Ecology Environment and Plant Sciences Stockholm University iBIOTROP Instituto de Biodiversidad Tropical Universidad San Francisco de Quito Department of Biology, San Francisco State University, San Francisco, CA, USA Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán AC, Mérida, Yucatán, México School of Ecological and Environmental Sciences East China Normal University Shanghai Engineering Research Center of Sustainable Plant Innovation Centre for Ecosystem Science School of Biological Earth and Environmental Sciences UNSW Sydney NSW Department of Ecology and Evolutionary Biology University of Michigan MI Department of Biosciences Rice University TX IFEVA Universidad de Buenos Aires Facultad de Agronomía, CONICET Biology Department Saint Mary's University NS Department of Biological Sciences, Universidad de los Andes Department of Biology and Biochemistry University of Houston TX Université de Rennes Department of Zoology and Biodiversity Research Centre University of British Columbia Department of Environmental Studies Dordt University Sioux Center IA Department of Biology Minneapolis Community and Technical College MN Department of Natural Sciences Ecology and Environment Research Centre Manchester Metropolitan University Instituto de Investigaciones en Ecosistemas y Sustentabilidad UNAM Department of Botany School of Biology Aristotle University of Thessaloniki Faculty of Biological and Environmental Science Organismal & Evolutionary Biology Research Programme University of Helsinki Institute of Biodiversity Animal Health and Comparative Medicine University of Glasgow Department of Biology Hendrix College Department of Ecological Science Vrije Universiteit Amsterdam Departamento de Ciencias Biológicas y Agropecuarias Universidad Técnica Particular de Loja Departamento de Biologia Universidade Federal de Santa Maria (UFSM) Department of Plant Sciences School of Biology College of Science University of Tehran NTNU University Museum Norwegian University of Science and Technology Red de Estudios Moleculares Avanzados Instituto de Ecología A. C. School of Biological Sciences, University of Reading, Whiteknights Park, Reading, Berkshire, UK Department of Biology Northern Arizona University AZ Department of Biological Sciences MacEwan University AB Max Planck Institute for Plant Breeding Research Departamento de Ecología Evolutiva Instituto de Ecología Universidad Nacional Autónoma de México Max Planck Institute of Molecular Plant Physiology Potsdam-Golm BIO5 Institute University of Arizona AZ Alaska Center for Conservation Science University of Alaska Anchorage Tropical Diversity, Royal Botanical Garden of Edinburgh Département de biologie Université de Moncton Department of Biological Sciences University of Manitoba MB Departments of Microbiology & Statistics University of Manitoba MB Department of Biology University of New Brunswick Department of Biology Kalamazoo College MI BioProtection Research Centre Lincoln University Departamento de Ciencias Facultad de Artes Liberales Universidad Adolfo Ibáñez Department of Ecology Evolution Behaviour University of Minnesota MN Department of Biological Sciences Brock University Department of Environmental Toxicology, University of California, Davis, CA, USA ICB - University of Talca School of Molecular and Life Science Curtin University College of Science Health Engineering and Education Murdoch University, Murdoch School of Life and Environmental Sciences University of Sydney NSW School of Biological Sciences, Monash University, Melbourne, VIC, Australia Department of Biological Sciences Wayne State University MI Department of Biology Western Oregon University, OR School of Natural Resources and the Environment University of Arizona AZ Departamento de Ecología Humana, Cinvestav Mérida Departamento de Ciencias Biológicas y Departamento de Ecología y Biodiversidad Facultad de Ciencias de la Vida, Universidad Andrés Bello Institute of Ecology and Biodiversity (IEB) Department of Biology Lund University Department of Biology Norwegian University of Science and Technology Escuela Superiro de Desarrollo Sustentable Universidad Autónoma de Guerrero -CONACYT Clarkson Secondary School Peel District School Board ON Homelands Sr. Public School Peel District School Board ON Department of Biological Sciences University of Illinois at Chicago Dufferin-Peel Catholic District School Board, St. James Catholic Global Learning Centre Department of Biosciences University of Calgary AB Ecological Processes Branch U.S. Army ERDC-CERL Department of Biology, Oberlin College, Oberlin, OH, USA Escuela Nacional de Estudios Superiores Unidad Morelia UNAM Institute of Evolution and Ecology University of Tübingen Tübingen Department of Evolutionary Biology and Environmental Studies University of Zurich, Winterthurerstrasse Urban Wildlife Institute Department of Conservation and Science, Lincoln Park Zoo Departamento de Ecología Universidad Católica de la Santísima Concepción Department of Biological Sciences University of Denver CO Department of Biological Sciences Mississippi State University MS Department of Biology Center for Computational & Integrative Biology Rutgers University-Camden Kunming Institute of Botany Chinese Academy of Sciences Department of Chemistry & Biochemistry Laurentian University ON Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering College of Life Sciences Beijing Normal University School of BioSciences, University of Melbourne, Melbourne, VIC, Australia Posgrado en Ciencias Biológicas Universidad Nacional Autónoma de México Department of Biological Sciences, Auburn University, Auburn, AL, USA Department of Entomology and Nematology, University of California, Davis, CA, USA Department of Biology University of New Mexico NM Department of Biology University of Wisconsin - Eau Claire Agriculture Institute Iranian Research Organization for Science and Technology (IROST) Department of Biology Colby College ME Instituto de Biología Universidad de Antioquia Department of Biology University of Massachusetts Boston MA Agricultural Biology Colorado State University CO Departamento de Biología Vegetal y Ecología Facultad de Biología Universidad de Sevilla, Av. Reina Mercedes s/n Facultad de Estudios Interdisciplinarios Centro GEMA- Genómica Universidad Mayor Evolutionary Ecology Group Naturalis Biodiversity Center Department of Biology and Chemistry Nipissing University ON, North Bay Center for Ecological Research Kyoto University Bonanza Creek Long Term Ecological Research Program University of Alaska Fairbanks Department of Botany and Molecular Evolution Senckenberg Research Institute and Natural History Museum Frankfurt Departamento de Biodiversidade Instituto de Biociências Univ Estadual Paulista - UNESP Nelson Institute for Environmental Studies University of Wisconsin-Madison WI Department of Biology, California State University, Northridge, Los Angeles, CA, USA Department of Ecology Swedish University of Agricultural Sciences Facultad de Ciencias y Biotecnologia Universidad CES Department of Biology Hofstra University Faculty of Biosciences and Aquaculture Nord University, Bodø Division of Biological Sciences, University of California San Diego, San Diego, CA, USA Department of Biology University of Richmond VA Estación de Biodiversidad Tiputini Colegio de Ciencias Biológicas y Ambientales Universidad San Francisco de Quito USFQ Department of Biological Sciences Institute of Environment Florida International University FL Agronomy Department University of Almería Department of Biological Sciences and Center for Urban Ecology and Sustainability Butler University IN Department of Biological Sciences Louisiana State University LA Faculty of Biological Sciences, Goethe University Frankfurt Institute of Biology Leiden Leiden University Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Department of Biology University of Louisville KY Organization for Programs on Environmental Science University of Tokyo CNRS AgroParisTech Ecologie Systématique et Evolution, Université Paris-Saclay Department of Biology, Providence College, Providence, RI, USA General Zoology Institute for Biology Martin Luther University Halle-Wittenberg International Arctic Research Center University of Alaska Fairbanks Science, Technology and Society Department, Rochester Institute of Technology, Rochester, NY, USA SLU Swedish Species Information Centre Swedish University of Agricultural Sciences Department of Biology Westfield State University MA Centre of New Technologies University of Warsaw Department of Biology, Stanford University, Stanford, CA, USA Plant Biology Department Michigan State University MI Biology Department Davidson College College of Horticulture and Forestry Sciences/ Hubei Engineering Technology Research Center for Forestry Information Huazhong Agricultural University School of Life Sciences Technical University of Munich School of Life Sciences Lanzhou University Institute of Ecology and Evolution University of Bern Department of Evolution Ecology and Behaviour University of Liverpool Departamento de Biodiversidade Instituto de Biociências Univ Estadual Paulista - UNESP

Toxin-resistant predators may suffer costs from eating chemically defended prey and do not feed exclusively on toxic prey. Common Gartersnakes (Thamnophis sirtalis (Linnaeus, 1758)) have been considered the drivers of an evolutionary arms race with highly toxic newts (genus Taricha Gray, 1850), which they consume with few or no deleterious effects. However, how frequently newts are consumed in nature is less clear. To address this question, we investigated the diets of Th. sirtalis at a site in central Oregon where snakes have high levels of resistance and newts have high levels of tetrodotoxin in the skin. Because snake diets are difficult to quantify using traditional means, we used stable isotopes to estimate the proportion of Th. sirtalis diets made up of newts. Our estimate for the proportion of Th. sirtalis diet made up of Rough-skinned Newts (Taricha granulosa (Skilton, 1849)) at this site is 3.2%. Mole Salamanders (genus Ambystoma Tschudi, 1838) were predicted to be the most important prey, followed by slugs, chorus frogs, and mice, with a very minor role for earthworms. Our results demonstrate that even though Th. sirtalis are physiologically capable of consuming toxic prey, they do not often do so. Generalist predators can be exposed to very strong selection from, and exert reciprocal selection on even rarely eaten, chemically defended prey.

Artificial light at night (ALAN) is a recognised disruptor of biological function and ecological communities. Despite increasing research effort, we know little regarding the effect of ALAN on woody plants, including trees, or its indirect effects on their colonising invertebrates. These effects have the potential to disrupt woodland food webs by decreasing the productivity of invertebrates and their secretions, including honeydew and lerps, with cascading effects on other fauna. Here, we cultivated juvenile river red gums (Eucalyptus camaldulensis) for 40 weeks under experimentally manipulated light (ALAN) or naturally dark (control) conditions. To assess direct impacts on tree growth, we took multiple measures of growth at four time periods, and also measured physiological function, biomass and investment in semi-mature trees. To assess experimentally the direct and indirect (tree-mediated) impacts of ALAN on invertebrates, from 19 weeks onwards, we matched and mismatched trees with their original ALAN environments. We colonised trees with a common herbivore of E. camaldulensis, the red gum lerp psyllid (Glycaspis nr. brimblecombei) and then measured the effects of current and historic tree lighting treatment on the psyllid life cycle. Our data revealed direct effects of ALAN on tree morphology: E. camaldulensis trees exposed to ALAN shifted biomass allocation away from roots and into leaves and increased specific leaf area. However, while the intensity of ALAN was sufficient to promote photosynthesis (net carbon gain) at night, this did not translate into variation in tree water status or photosystem adaptation to dim night-time light for ALAN-exposed trees. We found some evidence that ALAN had broad-scale community effects-psyllid nymphs colonising ALAN trees produced more lerps-but we found no other direct or indirect impacts of ALAN on the psyllid life cycle. Our results suggest that trees exposed to ALAN may share morphological responses with trees under dim daylight conditions. Further, ALAN may have significant 'bottom-up' effects on Eucalyptus woodland food webs through both trees and herbivores, which may impact higher trophic levels including woodland birds, mammals and invertebrates.

Anthropogenic factors, such as artificial light at night (ALAN), are increasingly linked to significant modifications in animal behaviours, such as foraging or migration. However, few studies have investigated directly whether the presence of ALAN affects the ability to find a mate (mate location). One direct effect of the presence of ALAN is that it can create a light barrier in an otherwise dark environment. This may have significant behavioural implications for nocturnally active species if it affects their ability to respond to potential mates. Our study, using the acoustically orienting Australian black field cricket, Teleogryllus commodus, determined experimentally whether the presence of a fragmented light environment influenced movement patterns of virgin females and males. Moreover, given the importance of male song for reproductive outcomes in this species, we assessed simultaneously whether such behaviours were modified by the presence of a male attraction call. We found that while initiation of movement was slower in the presence of ALAN, the behavioural shifts associated with its presence were relatively small compared to the influence of a broadcast male attraction call. The response to the male attraction call was typically stronger for females than for males, but both males and females modified aspects of behaviour when it was present regardless of whether their immediate environment was fragmented by artificial light at night or not. Artificial light at night may alter subtle aspects of movement and mating behaviour in this species, but ultimately does not provide a barrier to movement or mate location.

While there is huge promise in monitoring physiological parameters in free-living organisms, we also find high amounts of variability over time and space. This variation requires us to capitalize on long-term physiological monitoring to adequately address questions of population health, conservation status, or evolutionary trends as long-term sampling can examine ecoimmunological and endocrine interactions in wild populations while accounting for the variation that often makes ecophysiological field studies difficult to compare. In this study, we tested how immune efficacy and endocrinology interact while accounting for ecological context and environmental conditions in two snake species. Specifically, we measured bacterial killing ability, steroid hormones, and morphological characteristics in multiple populations of the Western Terrestrial Gartersnake (Thamnophis elegans) and Common Gartersnake (T. sirtalis) for multiple seasons over 6 years. Leveraging this long-term dataset, we tested how a broad immune measure and endocrine endpoints interact while accounting for individual traits, sampling date, and environmental conditions. Across both species, we found bacterial killing ability to be directly related to corticosterone (CORT) and temperature and greater overall in the spring compared to the fall. We found CORT and testosterone yielded relationships with individual sex, sampling temperature, and time of year. Wild populations can exhibit high amounts of variation in commonly collected physiological endpoints, highlighting the complexity and difficulty inherent in interpreting single endpoints without taking ecological and environmental conditions into account. Our study emphasizes the importance of reporting the environmental conditions under which the sampling occurred to allow for better contextualization and comparison between studies.

Light is fundamental to biological systems, affecting the daily rhythms of bacteria, plants, and animals. Artificial light at night (ALAN), a ubiquitous feature of urbanization, interferes with these rhythms and has the potential to exert strong selection pressures on organisms living in urban environments. ALAN also fragments landscapes, altering the movement of animals into and out of artificially lit habitats. Although research has documented phenotypic and genetic differentiation between urban and rural organisms, ALAN has rarely been considered as a driver of evolution. We argue that the fundamental importance of light to biological systems, and the capacity for ALAN to influence multiple processes contributing to evolution, makes this an important driver of evolutionary change, one with the potential to explain broad patterns of population differentiation across urban-rural landscapes. Integrating ALAN's evolutionary potential into urban ecology is a targeted and powerful approach to understanding the capacity for life to adapt to an increasingly urbanized world.

Increasing evidence suggests that key fitness-related behaviours of animals related to courtship and mating may be disrupted by anthropogenic stressors, including artificial light at night (i.e. light produced from anthropogenic sources). Despite its ubiquity in urban habitats, we currently know very little about how artificial night lighting affects the reproductive behaviours of most animals. Our study examined the effects of chronic (lifetime) exposure to one of four ecologically relevant intensities of artificial light at night (0, 1, 10 or 100 lx at night) on courtship and mating behaviours and acoustic sexual signalling in a common nocturnal and crepuscular insect, the Australian black field cricket, Teleogryllus commodus. We found that lifetime exposure to brighter (10–100 lx) artificial light at night affected some aspects of courtship and mating behaviour: it influenced mate choice and mating efficiency in a sex-specific manner, but did not affect the multivariate structure of male courtship calls. Our results suggest that chronic exposure to bright light at night may affect some aspects of mate choice and reproductive behaviour in this common insect, and warrants further study across taxa.

The neuropeptide kisspeptin and its receptor are essential for activation of the hypothalamic-pituitary-gonadal (HPG) axis and regulating reproduction. While the role of kisspeptin in regulating the HPG axis in mammals has been well established, little is known about the functional ability of kisspeptins to activate the HPG axis and associated behavior in non-mammalian species. Here we experimentally examined the effects of kisspeptin on downstream release of testosterone and associated aggression and display behaviors in the side-blotched lizard (Uta stansburiana). We found that exogenous treatment with kisspeptin resulted in an increase in circulating testosterone levels, castration blocked the kisspeptin-induced increase in testosterone, and testosterone levels in kisspeptin-treated animals were positively related to frequency of aggressive behaviors. This evidence provides a clear link between kisspeptin, testosterone, and aggressive behavior in lizards. Thus, it is likely that kisspeptin plays an important role more broadly in non-mammalian systems in the regulation of reproductive physiology and related behaviors.

While the use of nanoparticles has dramatically increased in recent years, the ecological consequences are not well known. In particular, little research has been done to investigate the potentially detrimental effects of nanoparticles on amphibians, especially across all life-history stages of salamanders and newts (caudates). To address this dearth in knowledge, we examined the effects of zinc oxide (ZnO) nanoparticles on egg, larval, and adult Rough-skinned Newts (Taricha granulosa). Chronic toxicity was tested on eggs and larvae, and acute toxicity was tested on eggs, larvae, and adults. For eggs, chronic exposure to ZnO nanoparticles caused higher mortality at 10.0 and 100.0 mg L(-1) compared to 0.0, 0.1, and 1.0 mg L(-1) . When given an acute exposure (24 hr) to 10.0 mg L(-1) nanoparticles at a late developmental stage, larvae hatched 5 days early, at a decreased developmental stage, and smaller size compared to the control. Chronic and acute exposure of larvae increased mortality up to 75% at both 10.0 and 100.0 mg L(-1) and exhibited sublethal effects, most dramatically, severe gill degradation. These results suggest nanoparticles can have lethal and sublethal effects on all life stages of amphibians.

Ecosystem disturbance through urbanization and agriculture, coupled with anthropogenic climate change, poses a pervasive threat to ecosystem health. Such landscape disturbance can manifest as salinization, particularly in Australia. Increasing salinization of both soils and waterways has the potential to render habitats unsuitable for amphibians. However, some species exist naturally in brackish and saline habitats, which suggests the capacity to adapt to salinization. To assess this adaptability in amphibians, we examined current brackish habitat utilization by a common Australian Froglet, Crinia signifera, and determined the tolerance of eggs and tadpoles of this species to acute and chronic exposure to brackish water. Crinia signifera lay eggs in brackish water and, through laboratory experiments, we determined that short-term survival in water up to 7.5 parts per thousand (ppt) salinity is possible but may vary among populations. Chronic exposure experiments demonstrated that C. signifera can successfully complete larval development to metamorphosis in brackish water (up to 5.0 ppt). Data presented here, together with previously published reports of salinity tolerance in other Australian frog species, collectively demonstrate a capacity for adaptation to landscape salinization. This has probably been mediated by an evolutionary history in the saline landscapes so common in Australia.

Amphibians are well known as osmotically sensitive organisms due to their highly permeable skin and eggs and, as such, biologists have mostly discounted their presence in saline environments. Yet, from the 1800s to the present day, scientists have repeatedly found amphibians living and breeding in a variety of saline coastal and inland habitats. Despite this plethora of observations, their presence in these habitats is still mostly ignored, and the last (and only) complete literature review documenting amphibians in brackish and saline habitats was completed over 50 yr ago. Here we provide a review of the literature of amphibians in saline waters and present data on 144 species, in 28 families, on every continent except Antarctica. In doing so, we make the case that salt tolerance in amphibians may not be as rare as generally assumed. Through classifying habitats and studies, we conclude that the abilities of dozens of species to locally adapt to coastal and inland saline habitats have been exte...

A variety of mechanisms are responsible for enabling an organism to escape a predatory attack, including behavioral changes, alterations in hormone levels, and production and/or secretion of toxins. However, these mechanisms are rarely studied in conjunction with each other. The Rough-skinned Newt ( Taricha granulosa ) is an ideal organism to examine the relationships between these mechanisms because its behavioral displays and toxin secretion during a predator attack are well documented and readily characterized. While we found no direct relationship between antipredator behavior and endogenous levels of corticosterone (CORT), antipredator behavior was inhibited when exogenous CORT and adrenocorticotropic hormone (ACTH) were administered, resulting in high circulating concentrations of CORT, indicating that CORT may play a role in mediating the behavior. There was no correlation between the animal’s toxicity and either CORT or behavior. The results of this study provide evidence that CORT plays an important, yet complex, role in the antipredator response of these amphibians.

Amphibians, due to their highly permeable skin and egg membranes, are generally considered osmotically challenged animals and, thus, highly sensitive to brackish and saline environments (Shoemaker and Nagy 1977; Duellman and Trueb 1994). Due to their intolerance of salt water, amphibians have long been mostly discounted from occurring in areas directly influenced by the ocean (Darwin 1872), and notes of salamanders in these habitats are rare (Neill 1958). On 14 May 2012, we observed a larval Dicamptodon tenebrosus (Coastal Giant Salamander) in the tidal area of Hunter Creek, Curry County, Oregon (UTM Zone 10, 382898.3E, 4693923.4N, WGS84), 177 m from the Pacific Ocean. The animal was active, appeared in good body condition, and had a snout-vent length of 5.5 cm and a total length of 9.7 cm (Fig 1A). We found the salamander in a shallow sand and rock pool on the edge of the stream (,30 cm deep), with a salinity of 1.0 ppt. Freshwater is generally ,0.5 ppt; brackish water is 0.5 to 20 ppt; sea-water typically averages 35 ppt (Boaden and Seed 1985). We measured salinities of up to 1.4 ppt in this area on other days, and these concentrations have been found to be detrimental to caudate amphibian embryonic and larval survival and development (Hopkins and others 2013a, 2013b, 2014). The water temperature at the time of our observation was 14.26C. This area of the stream is devoid of riparian and aquatic vegetation, except for some algae growing on the rocks, and is essentially on a sandy and rocky beach (Fig. 1B, 1C). Affected dramatically by the tides, the water level of this habitat changes by almost 1.0 m between high and low tides (Fig. 1B, 1C). A dead sea-star (Forcipulatida, Pisaster spp.) was located a few meters away from the salamander. This habitat is also affected by coastal storm events, which sometimes lead to sea-water washing through this area (Fig. 1D). As we only found 1 individual D. tenebrosus in the tidal area of this stream, it is possible that these storm events may prevent a larger population from inhabiting this habitat due to temporarily increased salinity beyond this species’ tolerance level, or simply because the lack of vegetation and cover in this habitat renders it unsuitable. It is also possible that this individual may have been washed downstream due to spring flooding, and may be sensitive to increased salinity levels, as was found for Ambystoma gracile (Northwestern Salamander) in British Columbia, where larvae were found dead or dying in a tidal area with presumably increased salinity (Carl 1949). The D. tenebrosus that we found in the tidal area did not, however, appear to be dead or dying, and may have been more salt-tolerant than the individuals observed by Carl (1949). Ferguson (1956) also found 1 larval D. tenebrosus approximately 20 m from the edge of the high tide area of a coastal stream in Lincoln County, Oregon, but salinity was not measured. To the best of our knowledge, salinity tolerance in D. tenebrosus has not yet been experimentally determined, and more work clearly needs to be done to determine tidal habitat utilization and salt tolerance in this species. Although reports of salamanders in tidal habitats in the Pacific Northwest are rare, Ferguson (1956) found Taricha granulosa (Roughskinned Newts) in the tidal area of a stream in southern Oregon, and we also found a large breeding group (over 60 individuals) of this species in the same tidal area as the Dicamptodon we observed (Hopkins and Hopkins, pers. obs.). Batrachoseps relictus (Relictual Slender Salamanders) were reported on a beach in California (Moss Landing, Monterey County) under driftwood near the tide line (Licht and others 1975; B Bury, pers. comm.), as was B. pacificus (Channel Islands Slender Salamander) in the Channel Islands (Hansen and others 2005). Batrachoseps relictus was experimentally determined to be physiologically adapted to the increased salinity in this habitat (Licht and others 1975). GENERAL NOTES

Freshwater organisms are increasingly exposed to elevated salinity in their habitats, presenting physiological challenges to homeostasis. Amphibians are particularly vulnerable to osmotic stress and yet are often subject to high salinity in a variety of inland and coastal environments around the world. Here, we examine the physiological responses to elevated salinity of rough-skinned newts (Taricha granulosa) inhabiting a coastal stream on the Pacific coast of North America and compare the physiological responses to salinity stress of newts living in close proximity to the ocean with those of newts living farther upstream. Although elevated salinity significantly affected the osmotic (body weight, plasma osmolality), stress (corticosterone), and immune (bactericidal ability) responses of newts, animals found closer to the ocean were generally less reactive to salt stress than those found farther upstream. Our results provide possible evidence for some physiological tolerance in this species to elevated salinity in coastal environments. As freshwater environments become increasingly saline and more stressful, understanding the physiological tolerances of vulnerable groups such as amphibians will become increasingly important to our understanding of their abilities to respond, to adapt, and, ultimately, to survive.

We investigated the effects of temperature on the growth and development of embryonic and early larval stages of a western North American amphibian, the rough-skinned newt (Taricha granulosa). We assigned newt eggs to different temperatures (7, 14, or 21°C); after hatching, we re-assigned the newt larvae into the three different temperatures. Over the course of three to four weeks, we measured total length and developmental stage of the larvae. Our results indicated a strong positive relationship over time between temperature and both length and developmental stage. Importantly, individuals assigned to cooler embryonic temperatures did not achieve the larval sizes of individuals from the warmer embryonic treatments, regardless of larval temperature. Our investigation of growth and development at different temperatures demonstrates carry-over effects and provides a more comprehensive understanding of how organisms respond to temperature changes during early development.