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21.
Jessica M. Driscoll Lauren E. Hay Melanie K. Vanderhoof Roland J. Viger 《Journal of the American Water Resources Association》2020,56(1):16-29
This study explores the viability of using simulated monthly runoff as a proxy for landscape‐scale surface‐depression storage processes simulated by the United States Geological Survey’s National Hydrologic Model (NHM) infrastructure across the conterminous United States (CONUS). Two different temporal resolution model codes (daily and monthly) were run in the NHM with the same spatial discretization. Simulated values of daily surface‐depression storage (treated as a decimal fraction of maximum volume) as computed by the daily Precipitation‐Runoff Modeling System (NHM‐PRMS) and normalized runoff (0 to 1) as computed by the Monthly Water Balance Model (NHM‐MWBM) were aggregated to monthly and annual values for each hydrologic response unit (HRU) in the CONUS geospatial fabric (HRU; n = 109,951) and analyzed using Spearman’s rank correlation test. Correlations between simulated runoff and surface‐depression storage aggregated to monthly and annual values were compared to identify where which time scale had relatively higher correlation values across the CONUS. Results show Spearman’s rank values >0.75 (highly correlated) for the monthly time scale in 28,279 HRUs (53.35%) compared to the annual time scale in 41,655 HRUs (78.58%). The geographic distribution of HRUs with highly correlated monthly values show areas where surface‐depression storage features are known to be common (e.g., Prairie Pothole Region, Florida). 相似文献
22.
Lauren M. Mathews 《Behavioral ecology and sociobiology》2002,51(5):426-432
There are at least two mechanisms by which social monogamy in the absence of biparental care may evolve: as a form of territorial cooperation, in which one or both sexes benefits by sharing a territory with a partner, and as a form of extended mate guarding, in which males guard females through entire, and perhaps multiple, reproductive cycles. I examined the effects of population variables (density, sex ratio, female synchrony) on male pairing behavior in the snapping shrimp, Alpheus angulatus, to test the hypothesis that social monogamy in this genus has evolved as a result of selection on males for long-term mate guarding of females. There was no evidence that pairing behavior changes with differences in population density; in a natural population, there was a 1:1 relationship between the number in pairs and local population density. In a laboratory experiment, males altered their pairing behavior in response to manipulated differences in sex ratio. Males in female-biased sex ratios were significantly more likely to abandon recently mated females than males in equivalent sex ratios, though there was no significant difference in the duration of pairing or the number of times males switched females. Observations of shrimp maintained for an extended period in the laboratory revealed no evidence that females molt and become sexually receptive synchronously, which would reduce the likelihood that a searching male would encounter additional receptive females. These data suggest that sex ratio may have contributed to the evolution of social monogamy in snapping shrimp, but provide no evidence that population density or female synchronous receptivity have contributed to the evolution of social monogamy. 相似文献
23.
Lauren M. Mathews 《Marine Biology》2007,152(3):645-655
Despite the apparent absence of geographic barriers, connectivity among marine populations may be restricted by, for example,
ecological or behavioral mechanisms. In such cases, populations may show genetic differentiation even over relatively small
spatial scales. Here, mitochondrial sequence data from the cytochrome oxidase I (COI) gene and seven polymorphic microsatellite
markers were used to investigate fine geographic scale population genetic structure in the snapping shrimp Alpheus angulosus, a member of the A. armillatus species complex, from collections in Florida, Jamaica, and Puerto Rico carried out from 1999 to 2005. The COI data showed
a deep divergence that separated these samples into two mitochondrial clades, but this divergence was not supported by the
microsatellite data. The COI data reflect past population divergence not reflected in extant population structure on the whole
genome level. The microsatellite data also revealed evidence for moderate population structure between populations as close
as ∼10 km, and no evidence for isolation by distance, as divergences between near populations were at least as strong as those
between more broadly separated populations. Overall, these data suggest a role for restricted gene flow between populations,
though the mechanisms that reduce gene flow in this taxon remain unknown. 相似文献
24.
Lauren E. Hay Gregory J. McCabe 《Journal of the American Water Resources Association》1998,34(1):103-112
ABSTRACT: Observed April 1 snowpack accumulations within and near the Gunnison River basin in southwestern Colorado are compared with simulations from the Rhea-orographic-precipitation model to determine if the model simulates reliable magnitudes and temporal and spatial variability in winter precipitation for the basin. Twenty simulations of the Rhea model were performed using‘optimal’parameter sets determined for 10-kilometer (km) grids (10-km by 10-km grid cells) through stochastic calibration. Comparisons of Rhea-model simulations of winter precipitation with April 1 snowpack accumulations at 32 snowcourse stations were performed for the years 1972–1990. For most stations and most years the Rhea model reliably simulates the temporal and spatial variability in April 1 snowpack accumulations. However, in general, the Rhea-model underestimates April 1 snowpack accumulations in the Gunnison River basin area, and the underestimation is greatest for locations that receive the largest amount of snow. A significant portion of the error in Rhea-model simulations is due to the calibration of the Rhea model using gauge-catch precipitation measurements which can be as much as 50 percent below actual snowfall accumulations. Additional error in the Rhea-model simulations is a result of the comparison of gridded precipitation values to observed values measured at points. 相似文献
25.
Ana Širović Lauren N. Williams Sara M. Kerosky Sean M. Wiggins John A. Hildebrand 《Marine Biology》2013,160(1):47-57
Fin whales (Balaenoptera physalus) produce a variety of low-frequency, short-duration, frequency-modulated calls. The differences in temporal patterns between two fin whale call types are described from long-term passive acoustic data collected intermittently between 2005 and 2011 at three locations across the eastern North Pacific: the Bering Sea, off Southern California, and in Canal de Ballenas in the northern Gulf of California. Fin whale calls were detected at all sites year-round, during all periods with recordings. At all three locations, 40-Hz calls peaked in June, preceding a peak in 20-Hz calls by 3–5 months. Monitoring both call types may provide a more accurate insight into the seasonal presence of fin whales across the eastern North Pacific than can be obtained from a single call type. The 40-Hz call may be associated with a foraging function, and temporal separation between 40- and 20-Hz calls may indicate the separation between predominately feeding behavior and other social interactions. 相似文献
26.
Alexandra?ZieritzEmail author Gemma?Clucas Lauren?Axtmann David?C.?Aldridge 《Marine Biology》2012,159(4):863-872
When feeding on blue mussels (Mytilus edulis), oystercatchers (Haematopus ostralegus) either stab into the mollusc’s gaping valves or hammer through its dorsal or ventral shell. Whilst the selectivity of hammering
and stabbing oystercatchers for specific prey morphologies has been well studied, the way in which the effects of environment
on M.
edulis morphology can in turn affect feeding methods of H. ostralegus is very poorly understood. Based on morphological analyses on randomly selected shells from three intertidal zones, this
study failed to detect differences in morphology or distribution of dorsally and ventrally hammered shells but confirms the
finding of previous authors that hammering oystercatchers select thinner mussels than stabbing birds. Additionally, we show
that this difference in optimal prey morphology can lead to spatial patterns in oystercatcher feeding behaviour. Whilst at
the low intertidal and higher mid intertidal zones, characterised by comparatively thick shells, most empty shells had apparently
been stabbed, hammering was the dominant feeding behaviour at the lower mid intertidal zone, where shells were thinner. Preference
of hammering birds for smaller mussels was not ubiquitous. Sagittal shell shape was predominantly influenced by allometric
growth effects and had only minor effect on prey selection. All oystercatchers preferred less inflated mussels, with the degree
of shell inflation gradually increasing with higher intertidal elevation. Our results illustrate the importance of small-scale
patterns in prey ecophenotypes in determining the distribution and feeding dynamics of wading birds. 相似文献
27.
A strong earthquake in the western Caribbean in 2009 had a catastrophic impact on uncemented, unconsolidated coral reefs in the central sector of the shelf lagoon of the Belizean barrier reef. In a set of 21 reef sites that had been observed prior to the earthquake, the benthic assemblages of 10 were eradicated, and one was partially damaged, by avalanching of their slopes. Ecological dynamics that had played out over the previous 23 years, including the mass mortalities of two sequentially dominant coral species and a large increase in the cover of an encrusting sponge, were instantaneously rendered moot in the areas of catastrophic reef-slope failure. Because these prior dynamics also determined the benthic composition and resilience of adjacent sections of reef that remained intact, the history of disturbance prior to the earthquake will strongly influence decadal-scale recovery in the failed areas. Geological analysis of the reef framework yielded a minimum return time of 2000-4000 years for this type of high-amplitude event. Anthropogenic degradation of ecosystems must be viewed against the backdrop of long-period, natural catastrophes, such as the impact of strong earthquakes on uncemented, lagoonal reefs. 相似文献
28.
Habitat corridors, a common management strategy for increasing connectivity in fragmented landscapes, have experimentally validated positive influences on species movement and diversity. However, long-standing concerns that corridors could negatively impact native species by spreading antagonists, such as disease, remain largely untested. Using a large-scale, replicated experiment, we evaluated whether corridors increase the incidence of plant parasites. We found that corridor impacts varied with parasite dispersal mode. Connectivity provided by corridors increased incidence of biotically dispersed parasites (galls on Solidago odora) but not of abiotically dispersed parasites (foliar fungi on S. odora and three Lespedeza spp.). Both biotically and abiotically dispersed parasites responded to edge effects, but the direction of responses varied across species. Although our results require additional tests for generality to other species and landscapes, they suggest that, when establishing conservation corridors, managers should focus on mitigating two potential negative effects: the indirect effects of narrow corridors in creating edges and direct effects of corridors in enhancing connectivity of biotically dispersed parasites. 相似文献
29.
Effects of Climate and Land Cover on Hydrology in the Southeastern U.S.: Potential Impacts on Watershed Planning 下载免费PDF全文
Jacob H. LaFontaine Lauren E. Hay Roland J. Viger R. Steve Regan Steven L. Markstrom 《Journal of the American Water Resources Association》2015,51(5):1235-1261
The hydrologic response to statistically downscaled general circulation model simulations of daily surface climate and land cover through 2099 was assessed for the Apalachicola‐Chattahoochee‐Flint River Basin located in the southeastern United States. Projections of climate, urbanization, vegetation, and surface‐depression storage capacity were used as inputs to the Precipitation‐Runoff Modeling System to simulate projected impacts on hydrologic response. Surface runoff substantially increased when land cover change was applied. However, once the surface depression storage was added to mitigate the land cover change and increases of surface runoff (due to urbanization), the groundwater flow component then increased. For hydrologic studies that include projections of land cover change (urbanization in particular), any analysis of runoff beyond the change in total runoff should include effects of stormwater management practices as these features affect flow timing and magnitude and may be useful in mitigating land cover change impacts on streamflow. Potential changes in water availability and how biota may respond to changes in flow regime in response to climate and land cover change may prove challenging for managers attempting to balance the needs of future development and the environment. However, these models are still useful for assessing the relative impacts of climate and land cover change and for evaluating tradeoffs when managing to mitigate different stressors. 相似文献
30.
Hazel A. Jackson Lawrence Percival-Alwyn Camilla Ryan Mohammed F. Albeshr Luca Venturi Hernán E. Morales Thomas C. Mathers Jonathan Cocker Samuel A. Speak Gonzalo G. Accinelli Tom Barker Darren Heavens Faye Willman Deborah Dawson Lauren Ward Vikash Tatayah Nicholas Zuël Richard Young Lianne Concannon Harriet Whitford Bernardo Clavijo Nancy Bunbury Kevin M. Tyler Kevin Ruhomaun Molly K. Grace Michael W. Bruford Carl G. Jones Simon Tollington Diana J. Bell Jim J. Groombridge Matt Clark Cock Van Oosterhout 《Conservation biology》2022,36(4):e13918
The pink pigeon (Nesoenas mayeri) is an endemic species of Mauritius that has made a remarkable recovery after a severe population bottleneck in the 1970s to early 1990s. Prior to this bottleneck, an ex situ population was established from which captive-bred individuals were released into free-living subpopulations to increase population size and genetic variation. This conservation rescue led to rapid population recovery to 400–480 individuals, and the species was twice downlisted on the International Union for the Conservation of Nature (IUCN) Red List. We analyzed the impacts of the bottleneck and genetic rescue on neutral genetic variation during and after population recovery (1993–2008) with restriction site-associated sequencing, microsatellite analyses, and quantitative genetic analysis of studbook data of 1112 birds from zoos in Europe and the United States. We used computer simulations to study the predicted changes in genetic variation and population viability from the past into the future. Genetic variation declined rapidly, despite the population rebound, and the effective population size was approximately an order of magnitude smaller than census size. The species carried a high genetic load of circa 15 lethal equivalents for longevity. Our computer simulations predicted continued inbreeding will likely result in increased expression of deleterious mutations (i.e., a high realized load) and severe inbreeding depression. Without continued conservation actions, it is likely that the pink pigeon will go extinct in the wild within 100 years. Conservation rescue of the pink pigeon has been instrumental in the recovery of the free-living population. However, further genetic rescue with captive-bred birds from zoos is required to recover lost variation, reduce expression of harmful deleterious variation, and prevent extinction. The use of genomics and modeling data can inform IUCN assessments of the viability and extinction risk of species, and it helps in assessments of the conservation dependency of populations. 相似文献