Crayfish in Southern Nevada

Hobbs, Horton H.; Zinn, Donald Joseph

doi:10.1126/science.107.2780.369-a

Cited by 7 publications

(6 citation statements)

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“…They have similar ranges: from the Rockies to the eastern seaboard and from the Ohio River drainage into Canada ; 0. virilis extends farther to the north (Pearse 1910, Turner 1926, Tack 1941, Hobbs and Zinn 1948, Williams 1954, Crocker 1957, Holthius 1962, Crocker and Barr 1968. Two closely related species, Orconectes immunis (Hagen) and Orconectes virilis (Hagen), are ecologically isolated to pond and stream, respectively.…”

mentioning

confidence: 99%

“…However, they do coexist in a short stretch of a river, and a competitive mechanism is revealed here which is an important segment of the ecological forces isolating these two species. They have similar ranges: from the Rockies to the eastern seaboard and from the Ohio River drainage into Canada ; 0. virilis extends farther to the north (Pearse 1910, Turner 1926, Tack 1941, Hobbs and Zinn 1948, Williams 1954, Crocker 1957, Holthius 1962, Crocker and Barr 1968.…”

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confidence: 99%

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Ecological Isolation and Competitive Exclusion in Two Crayfish (Orconectes Virilis and Orconectes Immunis)

Bovbjerg¹

1970

Ecology

155

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The two crayfiish, Orconectes virilis and 0. immunis, have similar ranges but are ecologically isolated within these ranges; the former species inhabits streams and lake margins, the latter inhabits ponds and sloughs.Field and experimental data suggest that the stream species, 0. virilis, is excluded from ponds by summer drying and periodic low oxygen periods of those ponds. It is not as competent a burrower as 0. immunis nor is it as tolerant of low oxygen levels.Neither current nor substratum excludes the pond species, 0. immunis, from the stream. But both field and laboratory observations strongly indicate a competitive exclusion of 0. immunis by 0. virilis. The latter was demonstrated to be intrinsically more aggressive in interspecific contacts, and in other experiments, evicted 0. immunis from crevices in the substratum.

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confidence: 99%

mentioning

confidence: 99%

Ecological Isolation and Competitive Exclusion in Two Crayfish (Orconectes Virilis and Orconectes Immunis)

Bovbjerg¹

1970

Ecology

155

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“…Western Mosquitofish were introduced to California in 1922 and subsequently to Nevada in 1934 (La Rivers 1962;Stockwell et al 1996), while Red Swamp Crayfish were used commonly in aquaculture in the 1930's and first documented in southern Nevada in the early 1940's (Hobbs 1948;Deacon et al 1964;Hobbs et al 1989;Miller et al 1989;Paulson and Martin 2014). Both species can have rapid population growth rates and broad ecological tolerances (Krumholz 1948;Huner and Lindqvist 1995;Pyke 2008;Paulson and Martin 2014), resulting in the ability to have substantial impacts on native fishes (Miller et al 1989;Meffe et al 1985).…”

Section: Procambarus Clarkiimentioning

confidence: 99%

“…For example, numerous poeciliid species invaded springs in southern Nevada (La Rivers 1962;Deacon et al 1964). Furthermore, non-native macroinvertebrates such as Red Swamp Crayfish were introduced into the southwest through means of commercial production, and likely dispersed from an aquaculture facility in the 1930's (Hobbs 1948;Deacon et al 1964;Hobbs et al 1989;Miller et al 1989;Deacon and Williams 1991;Paulson and Martin 2014). These introductions were often associated with the decline of native fishes (Deacon et al 1964).…”

Section: Introductionmentioning

confidence: 99%

The Combined Effects of Multiple Invasive Species on the Persistence of Experimental Populations of Imperiled Pahrump Poolfish

Bl¹,

Ca²

2021

Preprint

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Many ecosystems have been invaded by more than one non-native species, but research evaluating the combined effects of multiple invasive species has been limited. In the southwest USA, many aquatic systems have been invaded by multiple species such as non-native crayfish and non-native fishes. We used experimental mesocosms to test individual and combined effects of invasive Red Swamp Crayfish, Procambarus clarkii , and Western Mosquitofish, Gambusia affinis , on endangered Pahrump Poolfish, Empetrichthys latos. We found that crayfish alone reduced adult poolfish survival, however crayfish did not limit production of poolfish juveniles. By contrast, mosquitofish had no effect on survival of poolfish adults, but significantly reduced recruitment of juveniles. When both crayfish and mosquitofish were present, both adult survival and juvenile production were significantly decreased. These findings were consistent with the recent decline of a wild poolfish population from over 10,000 fish to less than 1,000 poolfish following the establishment of crayfish and mosquitofish. This study demonstrates that conservation management of the Pahrump Poolfish must have active management and removal of invasive species, otherwise extirpation and eventually extinction will likely occur and provides an example for the compounding effects of multiple invasive species for other study systems.

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“…These observations are sensitive enough to detect systematic effects within the observatory like time drifts or global changes of the observatory's 3-d velocity vector in the JPL ephemeris. Modelling of the arrival time of the pulse of a network of pulsars should enable us to correct for such systematics effects (Champion et al 2010, Hobbs et al 2012).…”

Section: Pos(aaska14)027mentioning

confidence: 99%

Real time cosmology - A direct measure of the expansion rate of the Universe with the SKA

Kloeckner¹,

Obreschkow²,

Martins³

et al. 2015

Proceedings of Advancing Astrophysics With the Square Kilometre Array — PoS(AASKA14)

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In recent years cosmology has undergone a revolution, with precise measurements of the microwave background radiation, large galaxy redshift surveys, and the discovery of the recent accelerated expansion of the Universe using observations of distant supernovae. All these groundbreaking observations have boosted our understanding of the Cosmos and its evolution. Because of this detailed understanding, more detailed tests of cosmological models require unprecedented precision that is only available with the next generation of astronomical observatories. Radio observations in particular will be able to access more independent modes than optical, infrared or X-ray facility and will show very different systematics compared to these other wavebands. The SKA enables us to do an ultimate test in cosmology by measuring the expansion rate of the Universe in real time. This can be done by a rather simple experiment of observing the neutral hydrogen (HI) signal of galaxies at two different epochs. The signal will encounter a change in frequency imprinted as the Universe expands over time and thus monitoring the drift in frequencies will provide a real time measure of the cosmic acceleration. Over a period of 12 years one would expected a frequency shift of the order of 0.1 Hz assuming a standard ΛCDM cosmology. However, monitoring such changes would require some modifications to the current baseline design of the SKA. In particular, the design needs to be adapted to achieve higher spectral resolution, at least within sub-bands (strong requirement), and to allow for a well monitored distribution of the local oscillator signal, preferably at milli-Hz accuracy over a period of 12 years (weaker requirement, which could be circumvented by pulsar observations). Based on the sensitivity estimates of the SKA and the number counts of the expected HI galaxies, it is shown that the number counts are sufficiently high to compensate for the observational uncertainties of the measurements and hence allow a statistical detection of the frequency shift. In addition, depending on the observational setup, it is shown that the evolution of the frequency shift in redshift space can be estimated to a precision of a percent. Although technically challenging, the direct measurement of the frequency shift and hence the cosmic acceleration can provide a model independent confirmation of dark energy. At highest precision it can distinguish between some competing cosmological models and combined with probes at other wavelength can break degeneracies and improving the figure of merit of cosmological parameters.

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Crayfish in Southern Nevada

Cited by 7 publications

References 0 publications

Ecological Isolation and Competitive Exclusion in Two Crayfish (Orconectes Virilis and Orconectes Immunis)

Ecological Isolation and Competitive Exclusion in Two Crayfish (Orconectes Virilis and Orconectes Immunis)

The Combined Effects of Multiple Invasive Species on the Persistence of Experimental Populations of Imperiled Pahrump Poolfish

Real time cosmology - A direct measure of the expansion rate of the Universe with the SKA

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