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77 record(s) found.

Papers & Reports Corticosterone Mediates a Growth-Survival Tradeoff for an Amphibian Exposed to Increased Salinity
Authors: B J Tornabene; Blake R Hossack; E J Crespi; C W Breuner
Outlet: Journal of Experimental Zoology Part A
Life-history tradeoffs are common across taxa, but growth-survival tradeoffs—which usually enhance survival at a cost to growth—are less frequently investigated. Increased salinity (NaCl) is a prevalent anthropogenic disturbance that may cause a growth-survival tradeoff for amphibians. Although physiological mechanisms mediating tradeoffs are seldom investigated, hormones are prime candidates. Corticosterone (CORT) is a steroid hormone that independently influences survival and growth and may provide mechanistic insight into growth-survival tradeoffs. We used 24-d trials to test effects of salinity (0 – 4000 mg/L Cl-) on growth, development, survival, CORT responses, and tradeoffs among traits of larval Northern Leopard Frogs (Rana pipiens). We also tested experimentally suppressed CORT signaling to determine whether CORT signaling mediates effects of salinity and life history tradeoffs . Increased salinity reduced survival, growth, and development. Suppressing CORT signaling in conjunction with salinity reduced survival further, but also attenuated negative effects of salinity on growth and development. CORT of control larvae increased or was stable with growth and development, but decreased with growth and development for those exposed to salinity. Therefore, salinity dysregulated CORT physiology. Across all treatments, larvae that survived had higher CORT than larvae that died. By manipulating CORT signaling, we provide strong evidence that CORT physiology mediates the outcome of a growth-survival tradeoff. To our knowledge, this is the first study to concomitantly measure tradeoffs between growth and survival and experimentally link these changes to CORT physiology. Identifying mechanistic links between stressors and fitness-related outcomes is critical to enhance our understanding of tradeoffs.
Papers & Reports Demography of the Oregon spotted frog along a hydrologically modified river
Authors: J C Rowe; Adam Duarte; C A Pearl; B McCreary; P K Haggerty; J W Jones; M J Adams
Date: 2021-06-21 | Outlet: Ecosphere
Altered flow regimes can contribute to dissociation between life history strategies and environmental conditions, leading to reduced persistence reported for many wildlife populations inhabiting regulated rivers. The Oregon spotted frog (Rana pretiosa) is a threatened species occurring in floodplains, ponds, and wetlands in the Pacific Northwest with a core range in Oregon, USA. All life stages of R. pretiosa are reliant on aquatic habitats, and inundation patterns across the phenological timeline can have implications for population success. We conducted capture-mark-recapture (CMR) sampling of adult and subadult R. pretiosa at three sites along the Deschutes River downstream from two dams that regulate flows. We related the seasonal extent of inundated habitat at each site to monthly survival probabilities using a robust design CMR model. We also developed matrix projection models to simulate population dynamics into the future under current river flows. Monthly survival was strongly associated with the extent and variability of inundated habitat, suggesting some within-season fluctuations at higher water levels could be beneficial. Seasonal survival was lowest in the winter for all three sites, owing to limited water availability and the greater number of months within this season relative to other seasons. Population growth for the two river-connected sites was most strongly linked to adult survival, whereas population growth at the river-disconnected site was most strongly tied to survival in juvenile stages. This research identifies population effects of seasonally limited water and highlights conservation potential of enhancing survival of particularly influential life stages.
Papers & Reports Water Temperature and Availability Shape the Spatial Ecology of a Hot Springs Endemic Toad (Anaxyrus williamsi)
Authors: Brian J Halstead; Patrick M Kleeman; Jonathan P Rose; Kristen J Fouts
Date: 2021-02-26 | Outlet: Herpetologica
Desert amphibians are limited to exploiting ephemeral resources and aestivating or to inhabiting scarce refuges of permanent water, such as springs. Understanding how amphibians use these resources is essential for their conservation. Dixie Valley Toads (Anaxyrus williamsi) are precinctive to a small system of cold and hot springs in the Dixie Valley, Nevada, USA. The toads have been petitioned for listing under the US Endangered Species Act, and information about how they use terrestrial and aquatic resources will help managers to conserve the toads and identify threats like geothermal energy development that might affect these toads. We used radiotelemetry to study the seasonal home ranges, movements, and habitat associations of Dixie Valley Toads in autumn 2018 and spring 2019. We found that toads were very closely associated with water in both seasons, with most observations occurring in water, especially for males in spring and all toads in the autumn. Even when found in terrestrial habitat, toads were a median distance of 4.2 m (95% credible interval = 3.3–5.3) from water; 95% of the time in spring and autumn, toads were within 14 m of water. Dixie Valley Toad habitat selection indicated a similar pattern, with selection in both spring and autumn for locations closer to water and for warmer water and substrates than at nearby available locations. In autumn, toads also avoided bare ground and terrestrial graminoids. Dixie Valley Toads selected brumation sites in, over (within dense vegetation), or near water, often near springs where water depths and temperatures are likely stable through the winter. The reliance of Dixie Valley Toads on water in spring, autumn, and during brumation suggests that alteration to historical flows and water temperatures are likely to affect the toads. Changes to the hydrothermal environment when toads are brumating could be particularly detrimental, potentially killing inactive toads.
Papers & Reports Estimating the survival of unobservable life stages for a declining frog with a complex life-history.
Authors: Jonathan P Rose; Sarah J Kupferberg; Clara A Wheeler; Patrick M Kleeman; Brian J Halstead
Date: 2021-02-15 | Outlet: Ecosphere 12(2):e03381
Demographic models enhance understanding of drivers of population growth and inform conservation efforts to prevent population declines and extinction. For species with complex life histories, however, parameterizing demographic models is challenging because some life stages can be dif?cult to study directly. Integrated population models (IPMs) empower researchers to estimate vital rates for organisms that have cryptic or widely dispersing early life stages by integrating multiple demographic data sources. For a stream-inhabiting frog(Rana boylii) that is declining through much of its range in Oregon and California, USA, we collected egg-mass counts and capture–mark–recapture data on adults from two populations in California to ?t IPMs that estimate adult abundance and the survival rate of both marked and unobserved life stages. Estimates of adult abundance based on long-term monitoring of egg-mass counts showed that study populations ?uctuated greatly inter-annually but were stable at longer timescales (i.e., decades). Adult female survival during 5–6 yr of capture–mark–recapture study periods was nearly equal in each population. Survival rate of R. boylii eggs to the subadult stage is low on average (0.002) but highly variable among years depending on post-oviposition stream ?ow. Population viability analysis showed that survival of adult and subadult life stages has the greatest proportional effect on population growth; the survival of egg and tadpole life stages, however, is more malleable by management interventions. For example, simulations showed head-starting of tadpoles, salvaging stranded egg masses, and limiting aseasonal pulsed ?ows could dramatically reduce the threat of extirpation. This study demonstrates the value of integrating multiple demographic data sources to construct models of population dynamics in species with complex life histories.
Papers & Reports Baseline Conditions and Projected Future Hydro-Climatic Change in National Parks in the Conterminous United States
Authors: W A Battaglin
Date: 2020-06-15 | Outlet: Water 2020, 12(6), 1704;
Abstract: The National Park Service (NPS) manages hundreds of parks in the United States, and many contain important aquatic ecosystems and/or threatened and endangered aquatic species vulnerable to hydro-climatic change. More effective management of park resources under future hydro-climatic uncertainty requires information on both baseline conditions and the range of projected future conditions. A monthly water balance model was used to assess baseline (1981–1999) conditions and a range of projected future hydro-climatic conditions in 374 NPS parks. General circulation model outputs representing 214 future climate simulations were used to drive the model. Projected future changes in air temperature (T), precipitation (p), and runoff (R) are expressed as departures from historical baselines. Climate simulations indicate increasing T by 2030 for all parks with 50th percentile simulations projecting increases of 1.67 °C or more in 50% of parks. Departures in 2030 p indicate a mix of mostly increases and some decreases, with 50th percentile simulations projecting increases in p in more than 70% of parks. Departures in R for 2030 are mostly decreases, with the 50th percentile simulations projecting decreases in R in more than 50% of parks in all seasons except winter. Hence, in many NPS parks, R is projected to decrease even when p is projected to increase because of increasing T in all parks. Projected changes in future hydro-climatic conditions can also be assessed for individual parks, and Rocky Mountain National Park and Congaree National Park are used as examples.
Papers & Reports Effects of experimental warming and nutrient enrichment on wetland communities at the Arctic’s edge
Authors: J M Davenport; L Fishback; Blake R Hossack
Date: 2020-09 | Outlet: Hydrobiologia
The disproportionate effects of warming for high-latitude, freshwater ecosystems has been well documented, but in some areas, changes have been further impacted by human-subsidized increases of waterfowl. To gain insight into how predicted changes in temperature and nutrient inputs might affect ecosystem function, we conducted a mesocosm experiment in the Canadian Subarctic with three levels of simulated goose enrichment and warming to measure changes in size and survival of larval wood frogs and boreal chorus frogs and primary productivity (phytoplankton and periphyton biomass). Our results highlight that the consequences of these rapid changes are non-linear and even non-intuitive, with species-specific consumer and ecosystem responses that depend on the magnitude of temperature and nutrient changes as well as community composition.
Papers & Reports Survival estimates for the invasive American Bullfrog
Authors: P E Howell; Erin Muths; Brent H Sigafus; Blake R Hossack
Outlet: Amphibia-Reptilia
We used five years of capture mark-recapture data to estimate annual apparent survival of post-metamorphic bullfrogs in a population on the Buenos Aires National Wildlife Refuge in their invaded range in Arizona, U.S.A.
Papers & Reports Estimating inundation of small waterbodies with sub-pixel analysis of Landsat imagery: long-term trends in surface water area and evaluation of common drought indices
Authors: I Sall; Christopher J Jarchow; Brent H Sigafus; Lisa A Eby; M J Forzley; Blake R Hossack
Outlet: Remote Sensing in Ecology and Conservation
Small waterbodies are numerically dominant in many landscapes and provide several important ecosystem services, but automated measurement of waterbodies smaller than a standard Landsat pixel (0.09 ha) remains challenging. To further evaluate sub-Landsat pixel techniques for estimating inundation extent of small waterbodies (basin area: 0.061.79 ha), we used a partial spectral unmixing method with matched filtering applied to September 1985–2018 Landsat 5 and 8 imagery from southern Arizona, USA. We estimated trends in modeled surface water area each September and evaluated the ability of several common drought indices to explain variation in mean water area. Our methods accurately classified waterbodies as dry or inundated (Landsat 5: 91.3%; Landsat 8: 98.9%) and modeled and digitized surface water areas were strongly correlated (R2 = 0.700.92; bias = -0.024 – -0.015 ha). Estimated surface water area was best explained by the 3-month seasonal standardized precipitation index (SPI03; July?September) and. We found a wide range of estimated relationships between drought indices (e.g., SPI vs. Palmer Drought Severity Index) and estimated water area, even for different durations of the same drought index (e. g., SPI01 vs SPI12). Mean surface area of waterbodies decreased by ~14% from September 1985 to September 2018, which matched declines in annual precipitation in the area and is consistent with broader trends of reduced inundation extent based on larger waterbodies. Estimated of surface water area and trends over time were also consistent when we limited analyses to waterbodies ? 0.04 ha or those that varied most in size (based on CV). These results emphasize the importance of understanding local systems when relying on drought indices to infer variation in past or future surface water dynamics. Several challenges remain before widespread application of sub-pixel methods is feasible, but our results provide further evidence that partial spectral unmixing with matched filtering provides reliable measures of inundation extent of small waterbodies.
Papers & Reports Species-specific responses to wetland mitigation among amphibians in the Greater Yellowstone Ecosystem
Authors: L K Swartz; W H Lowe; Erin Muths; Blake R Hossack
Date: 2020 | Outlet: Restoration Ecology 28:206-214
Habitat loss and degradation are leading causes of biodiversity declines, therefore assessing the capacity of created mitigation wetlands to replace habitat for wildlife has become a management priority. We used single season occupancy models to compare occurrence of larvae of four species of pond-breeding amphibians in wetlands created for mitigation, wetlands impacted by road construction, and unimpacted reference wetlands along a highway corridor in the Greater Yellowstone Ecosystem, U.S.A. Created wetlands were shallow and had less aquatic vegetation and surface area than impacted and reference wetlands. Occupancy of barred tiger salamander (Ambystoma mavortium) and boreal chorus frog (Pseudacris maculata) larvae was similar across wetland types, whereas boreal toads (Anaxyrus boreas) occurred more often in created wetlands than reference and impacted wetlands. However, the majority of created wetlands (> 80%) dried partially or completely before amphibian metamorphosis occurred in both years of our study, resulting in heavy mortality of larvae and, we suspect, little to no recruitment. Columbia spotted frogs (Rana luteiventris), which require emergent vegetation that is not common in newly-created wetlands, occurred commonly in impacted and reference wetlands but were found in only one created wetland. Our results show that shallow created wetlands with little aquatic vegetation may be attractive breeding areas for some amphibians, but may result in high mortality and little recruitment if they fail to hold water for the entire larval period.
Papers & Reports Floodplains provide important amphibian habitat despite multiple ecological threats
Authors: M Holgerson; Adam Duarte; M P Hayes; M J Adams; J Tyson; K Douville; A Strecker
Date: 2019-09-03 | Outlet: Ecosphere
Floodplain ponds and wetlands are productive and biodiverse ecosystems, yet they face multiple threats including altered hydrology, land use change, and non-native species. Protecting and restoring important floodplain ecosystems requires understanding how organisms use these habitats and respond to altered environmental conditions. We developed Bayesian models to evaluate occupancy of six amphibian species across 103 off-channel aquatic habitats in the Chehalis River floodplain, Washington State, USA. The basin has been altered by changes in land use, reduced river-wetland connections, and the establishment of non-native American bullfrogs (Rana catesbeiana = Lithobates catesbeianus) and centrarchid fishes, all of which we hypothesized could influence native amphibian occupancy. Despite potential threats, the floodplain habitats had relatively high rates of native amphibian occupancy, particularly when compared to studies from non-floodplain habitats within the species’ native ranges. The biggest challenge for native amphibians appears to be non-native centrarchid fishes, which strongly reduced occupancy of two native amphibians: the northern red-legged frog (Rana aurora) and the northwestern salamander (Ambystoma gracile). Emergent vegetative cover increased occupancy probability for all five native amphibian species, indicating that plant-management may offer a strategy to counter the negative effect of centrarchids by providing refuge from predation. We found that temporary and permanent hydroperiod sites supported different species, hence both should be conserved on the landscape. Lastly, human-created and natural ponds had similar amphibian occupancy patterns, suggesting that pond construction offers a viable strategy for adding habitats to the floodplain landscape. Overall, floodplain ponds and wetlands provide important amphibian habitat, and we offer management strategies that will bolster amphibian occupancy in an altered floodplain landscape.
Authors: S M Billerman
Date: 2019-09 | Outlet: Canadian Journal of Zoology
The metapopulation concept has far reaching implications in ecology and conservation biology. Hanski’s criteria operationally define metapopulations, yet testing them is hindered by logistical and financial constraints inherent to the collection of long-term demographic data. Hence, ecologists and conservationists often assume metapopulation existence for dispersal-limited species that occupy patchy habitats. To advance understanding of metapopulation theory and improve conservation of metapopulations, we used population and landscape genetic tools to develop a methodological framework for evaluating Hanski’s criteria. We used genotypic data (11 microsatellite loci) from a purported metapopulation of boreal chorus frogs (Pseudacris maculata; Agassiz 1850) in Colorado, USA to test Hanski’s four criteria. We found support for each criterion: (1) significant genetic differentiation between wetlands, suggesting distinct breeding populations (2) wetlands had small effective population sizes and recent bottlenecks, suggesting populations do not experience long-term persistence, (3) population graphs provided evidence of gene flow between patches, indicating potential for recolonization, and (4) multiscale bottleneck analyses suggest asynchrony, indicating that simultaneous extinction of all populations was unlikely. Our methodological framework provides a logistically and financially feasible alternative to long-term demographic data for identifying amphibian metapopulations.
Papers & Reports Effects of experimental warming and simulated goose enrichment on wetland communities at the Arctic?s edge
Authors: J M Davenport; L Fishback; Blake R Hossack
Date: 2020 | Outlet: Hydrobiologia (2020) 847:3677–3690
Global warming-related changes to freshwater
ecosystems in Arctic and Subarctic regions have
been magnified by nutrient input from increasing
waterfowl populations. To gain insight into how these
changes might affect ecosystem function, we conducted
a mesocosm experiment in the Subarctic by
enriching N and P (1 9, 10 9, and 20 9 treatments)
and increasing mean water temperatures B 3C. We
measured responses of two species of larval amphibians,
periphyton, and phytoplankton. Wood frog
(Rana sylvatica) larvae developed quicker (odds ratio
[OR] for 1C increase = 0.903, 95% CI 0.892–0.912)
and were more likely to metamorphose (OR 1.076,
95% CI 0.022–14.73) in warmer waters. Boreal chorus
frogs (Pseudacris maculata) also developed quicker
with warmer temperatures (OR 0.880, 95% CI
0.860–0.900), despite a non-significant trend toward
reduced survival (OR 0.853, 95% CI 0.696–1.039).
Periphyton and phytoplankton concentrations
increased with nutrient additions, as did size of wood
frog metamorphs. Periphyton and phytoplankton did
not vary with temperature, but periphyton was limited
by tadpole abundance. Our results highlight the
potential for non-linear responses to ecosystem
change, with species-specific consumer and ecosystem
responses that depend on the magnitude of
Papers & Reports Using Full and Partial Unmixing Algorithms to Estimate the Inundation Extent of Small, Isolated Stock Ponds in an Arid Landscape
Authors: Christopher J Jarchow; Brent H Sigafus; Erin Muths; Blake R Hossack
Date: 2019-08 | Outlet: Wetlands
Many natural wetlands around the world have disappeared or been replaced, resulting in the dependence of many wildlife species on small, artificial earthen stock ponds. These ponds provide critical wildlife habitat, such that the accurate detection of water and assessment of inundation extent is required. We applied a full (linear spectral mixture analysis; LSMA) and partial (matched filtering; MF) spectral unmixing algorithm to a 2007 Landsat 5 and a 2014 Landsat 8 satellite image to determine the ability of a time-intensive (i.e., more spectral input; LSMA) vs. a more efficient (less spectral input; MF) spectral unmixing approach to detect and estimate surface water area of stock ponds in southern Arizona, USA and northern Sonora, Mexico. Spearman rank correlations (rs) between modeled and actual inundation areas less than a single Landsat pixel (< 900 m2) were low for both techniques (rs range = 0.22 to 0.62), but improved for inundation areas > 900 m2 (rs range = 0.34 to 0.70). Our results demonstrate that the MF approach can model ranked inundation extent of known pond locations with results comparable to or better than LSMA, but further refinement is required for estimating absolute inundation areas and mapping wetlands < 1 Landsat pixel.
Papers & Reports Seeking shelter from the storm: Conservation and management of imperiled species in a changing climate.
Authors: Susan C Walls; William J Barichivich; J Chandler; A M Meade; M Milinichik; K M O'Donnell; M E Owens; T Peacock; J Reinman; O E Wetsch
Date: 2019-05-30 | Outlet: Ecology and Evolution 9(12): 7122-7133.
Climate change is anticipated to exacerbate the extinction risk of species whose persistence is already compromised by habitat loss, invasive species, disease, and other stressors. In coastal areas of the southeastern United States, many imperiled vertebrates are vulnerable to hurricanes, which climate models predict to become more severe in the 21st century. Despite this escalating threat, explicit adaptation strategies that address hurricane threats, in particular, and climate change more generally, are largely underrepresented in recovery planning and implementation. Our purpose herein is to provide a basis for stronger emphasis on strategic planning for imperiled species facing the increasing threat of catastrophic hurricanes. Our reasoning comes from observations of short-term environmental and biological impacts of Hurricane Michael, which impacted the Gulf Coast of the southeastern USA in October 2018. During this storm, St. Marks National Wildlife Refuge, located along the northern Gulf of Mexico?s coast in the panhandle region of Florida, experienced storm surge that was 2.3 to 3.3 m above sea level. Storm surge pushed sea water into some ephemeral freshwater ponds used for breeding by the federally-threatened Frosted Flatwoods Salamander (Ambystoma cingulatum). After the storm, specific conductance across all ponds varied from 80 to 23,100 ?S/cm,compared to 75 to 445 uS/cm in Spring 2018. For those overwashed wetlands that were measured in both Spring and Fall 2018, post-hurricane conductance observations averaged nearly 100 times greater than in the previous Spring, setting the stage for varying population responses across this coastal landscape. Importantly, we found live individual flatwoods salamanders at both overwashed and non-overwashed sites, although we cannot yet assess the demographic consequences of this storm. We outline actions that could be incorporated into climate adaptation strategies and recovery planning for imperiled species, like A. cingulatum, that are associated with freshwater coastal wetlands in hurricane-prone regions.
Papers & Reports Persistent salinization of surface and groundwater resources from legacy energy development in the Prairie Pothole Region
Authors: T Preston; Chauncey W Anderson; J N Thamke; Blake R Hossack; K J Skalak; I M Cozzarelli,
Outlet: Science of the Total Environment 690:522-533
Papers & Reports Drought-mediated extinction of an arid-land amphibian: insights from a spatially explicit dynamic occupancy model
Authors: E R Zylstra; D E Swann; Blake R Hossack; Erin Muths; R J Steidl
Outlet: Ecological Applications 29: e01859
Understanding how natural and anthropogenic processes affect population dynamics of species with patchy distributions is critical to predicting their responses to environmental changes. Despite considerable evidence that demographic rates and dispersal patterns vary temporally in response to an array of biotic and abiotic processes, few applications of metapopulation theory have sought to explore factors that explain spatio-temporal variation in extinction or colonization rates. To facilitate exploring these factors, we extended a spatially explicit model of metapopulation dynamics to create a framework that requires only binary presence-absence data, makes few assumptions about the dispersal process, and accounts for imperfect detection. We apply this framework to 22 years of biannual survey data for lowland leopard frogs, Lithobates yavapaiensis, an amphibian that inhabits arid stream systems in the southwestern U.S. and northern Mexico. Our results highlight the importance of accounting for factors that govern temporal variation in transition probabilities, as both extinction and colonization rates varied with hydrologic conditions. Specifically, local extinctions were more frequent during drought periods, particularly at sites without reliable surface water. Colonization rates increased when larval and dispersal periods were wetter than normal, which increased the probability that potential emigrants metamorphosed and reached neighboring sites. Extirpation of frogs from one watershed during a period of severe drought demonstrated the influence of site-level features, as frogs persisted only in areas where most sites held water consistently and where the amount of sediment deposited from high-elevation wildfires was low. Application of our model provided novel insights into how climate-related processes affected the distribution and population dynamics of an arid-land amphibian. The approach we describe has application to a wide array of species that inhabit patchy environments, can improve our understanding of factors that govern metapopulation dynamics, and can inform strategies for conservation of imperiled species.
Papers & Reports Seasonal median daily water depths for study wetlands in the Tamarac National Wildlife Refuge, the St. Croix National Scenic Riverway, the North Temperate Lakes Long-term Research area, and the Upper Mississippi River study area from 2008-2012
Authors: W J Sadinski; M Roth
Date: 2018-09-06 | Outlet: U.S. Geological Survey data release,
To relate water levels in our study wetlands to temperature, precipitation, wetland water depth, and amphibian calling activity, we installed one pressure logger in the deepest spot we could find in each wetland. Soon after thawing conditions allowed, we drove a plastic pipe (anchor pipe) into the sediments at the deepest location and secured another pipe to it that contained one pressure logger (Global Water Model 14 and 15 [College Station, TX, USA] or Onset Computer Corporation Model U20-001-04 [Bourne, MA, USA]) suspended approximately 2.5 cm above the sediments. We installed additional individual pressure loggers in the upper part of the logger pipes (in air) at select locations to measure barometric pressure for calibrating the submerged loggers’ readings. We measured pressure once per hour and used software supplied by the logger manufacturers to upload and convert data to depth at the end of each season.
Papers & Reports Multi-year data from satellite- and ground-based sensors show details and scale matter in assessing climate's effects on wetland surface water, amphibians, and landscape conditions
Authors: W J Sadinski; A L Gallant; M Roth; J Brown; G Senay; W Brininger; P M Jones; J Stoker
Date: 2018-09-07 | Outlet: PLoS ONE 13(9): e0201951
Long-term, interdisciplinary studies of relations between climate and ecological conditions on wetland-upland landscapes have been lacking, especially studies integrated across scales meaningful for adaptive resource management. We collected data in situ at individual wetlands, and via satellite for surrounding 4-km2 landscape blocks, to assess relations between annual weather dynamics, snow duration, phenology, wetland surface-water availability, amphibian presence and calling activity, greenness, and evapotranspiration in four U.S. conservation areas from 2008 to 2012. Amid recent decades of relatively warm growing seasons, 2012 and 2010 were the first and second warmest seasons, respectively, dating back to 1895. Accordingly, we observed the earliest starts of springtime biological activity during those two years. In all years, early-season amphibians first called soon after daily mean air temperatures were ? 0°C and snow had mostly melted. Similarly, satellite-based indicators suggested seasonal leaf-out happened soon after snowmelt and temperature thresholds for plant growth had occurred. Daily fluctuations in weather and water levels were related to amphibian calling activity, including decoupling the timing of the onset of calling at the start of season from the onset of calling events later in the season. Within-season variation in temperature and precipitation also was related to vegetation greenness and evapotranspiration, but more at monthly and seasonal scales. Wetland water levels were moderately to strongly associated with precipitation and early or intermittent wetland drying likely reduced amphibian reproduction success in some years, even though Pseudacris crucifer occupied sites at consistently high levels. Notably, satellite-based indicators of landscape water availability did not suggest such consequential, intra-seasonal variability in wetland surface-water availability. Our cross-disciplinary data show how temperature and precipitation interacted to affect key ecological relations and outcomes on our study landscapes. These results demonstrate the value of multi-year studies and the importance of scale for understanding actual climate-related effects in these areas.
Papers & Reports Pharmaceuticals, Hormones, Pesticides, and other Bioactive Contaminants in Water, Sediment, and Tissue from Rocky Mountain National Park, 2012-2013
Authors: W A Battaglin; Paul M Bradley; L Iwanowicz; Celeste A Journey; V Blazer
Date: 2018-06-05 | Outlet: Science of the Total Environment 643:651-673
Pharmaceuticals, hormones, pesticides, and other bioactive contaminants (BCs) are commonly detected in surface water and bed sediment in urban and suburban areas, but these contaminants are understudied in remote locations. In Rocky Mountain National Park (RMNP), Colorado, USA, BCs may threaten the reproductive success and survival of native aquatic species, benthic communities, and pelagic food webs. In 2012-2013, 67 water, 57 sediment, 63 fish, 10 frog, and 12 quality-control samples (8 water and 4 sediment) were collected from 20 sites in RMNP. Samples were analyzed for 369 parameters including 149 pharmaceuticals, 22 hormones, 137 pesticides, and 61 other chemicals or conditions to provide a representative assessment of BC occurrence within RMNP. Results indicate that BCs were detected in water and/or sediment from both remote and more accessible locations in RMNP. The most commonly detected BCs in water were caffeine, camphor, para-cresol, and DEET; and the most commonly detected BCs in sediment were indole, 3-methyl-1H-indole, para-cresol, and 2,6-dimethyl-naphthalene. Some detected contaminants, including carbaryl, caffeine, and oxycodone, are clearly attributable to direct local human input, whereas others may be transported into the park atmospherically (e.g., atrazine) or have local natural sources (e.g., para-cresol). One or more pharmaceuticals were detected in at least 1 sample from 15 of 20 sites. Most of the 29 detected pharmaceuticals are excreted primarily in human urine, not feces. Elevated net estrogenicity was observed in 18% of water samples, and elevated vitellogenin in blood was observed in 12% of male trout, both evidence of potential endocrine disruption. Hormone concentrations in sediment tended to be greater than concentrations in water. Most BCs were observed at concentrations below those not expected to pose adverse effects to aquatic life. Results indicate that even in remote locations aquatic wildlife can be exposed to pharmaceuticals, hormones, pesticides, and other bioactive contaminants.
Papers & Reports Increasing connectivity between metapopulation ecology and landscape ecology
Authors: P E Howell; Erin Muths; Blake R Hossack; Brent H Sigafus; R B Chandler
Date: 2018-02 | Outlet: Ecology 99(5), 2018, pp. 1119–1128
Abstract. Metapopulation ecology and landscape ecology aim to understand how spatial structure
influences ecological processes, yet these disciplines address the problem using fundamentally different modeling approaches. Metapopulation models describe how the spatial distribution of patches affects colonization and extinction, but often do not account for the heterogeneity in the landscape between patches. Models in landscape ecology use detailed descriptions of landscape structure, but often without considering colonization and extinction dynamics. We present a novel spatially explicit modeling framework for narrowing the divide between these disciplines to advance understanding of the effects of landscape structure on metapopulation dynamics. Unlike previous efforts, this framework allows for statistical inference on landscape resistance to colonization using empirical data. We demonstrate the approach using 11 yr of data on a threatened amphibian in a desert ecosystem. Occupancy data for Lithobates chiricahuensis (Chiricahua leopard frog) were collected on the Buenos Aires National Wildlife Refuge (BANWR), Arizona, USA from 2007 to 2017 following a reintroduction in 2003. Results indicated that colonization dynamics were influenced by both patch characteristics and landscape structure. Landscape resistance increased with increasing elevation and distance to the nearest streambed. Colonization rate was also influenced by patch quality, with semi-permanent and permanent ponds contributing substantially more to the colonization of neighboring ponds relative to intermittent ponds. Ponds that only hold water intermittently also had the highest extinction rate. Our modeling framework can be widely applied to understand metapopulation dynamics in complex landscapes, particularly in systems in which the environment between habitat patches influences the colonization process.