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766 record(s) found.

Papers & Reports Population declines lead to replicate patterns of internal range structure at the tips of the distribution of the California red-legged frog (Rana draytonii)
Authors: Jonathan Q Richmond; Adam R Backlin; Patricia Tatarian; B G Solvesky; Robert N Fisher
Date: 2014 | Outlet: Biological Conservation
Demographic declines and increased isolation of peripheral populations of the threatened California red-legged frog(Rana draytonii)have led to the formation of internal range boundaries at opposite ends of the species’ distribution. While the population genetics of the southern internal boundary has been studied in some detail, similar information is lacking for the northern part of the range. In this study, we used microsatellite and mtDNA data to examine the genetic structuring and diversity of some of the last remaining R. draytonii populations in the northern Sierra Nevada, which collectively form the northern external range boundary. We compared these data to coastal populations in the San Francisco Bay Area, where the species is notably more abundant and still exists throughout much of its historic range. We show that ‘external’ Sierra Nevada populations have lower genetic diversity and are more differentiated from one another than their ‘internal’ Bay Area counterparts. This same pattern was mirrored across the distribution in California, where Sierra Nevada and Bay Area populations had lower allelic variability compared to those previously studied in coastal southern California. This genetic signature of northward range expansion was mirrored in the phylogeography of mtDNA haplotypes; northern Sierra Nevada haplotypes showed greater similarity to haplotypes from the south Coast Ranges than to the more geographically proximate populations in the Bay Area. These data cast new light on the geographic origins of Sierra Nevada R. draytonii populations and highlight the importance of distinguishing the genetic effects of contemporary demographic declines from underlying signatures of historic range expansion when addressing the most immediate threats to population persistence. Because there is no evidence of contemporary gene flow between any of the Sierra Nevada R. draytonii populations, we suggest that management activities should focus on maintaining and creating additional ponds to support breeding within typical dispersal distances of occupied habitat.
Papers & Reports ANAXYRUS BOREAS (Western Toad). PREDATION
Authors: L K Swartz; C R Faurot-Daniels; Blake R Hossack; Erin Muths
Date: 2014 | Outlet: Herpetological Review 45:303
Papers & Reports Chilled Frogs are Hot: Hibernation and Reproduction of the Endangered Mountain Yellow-Legged Frog (Rana muscosa)
Authors: F E Santana; R R Swaisgood; J M Lemm; Robert N Fisher; R W Clark
Date: 2015-02-11 | Outlet: Endangered Species Research 27:43-51
In the face of the sixth great extinction crisis, it is imperative to establish effective breeding protocols for amphibian conservation breeding programs. Efforts should not proceed by trial and error, nor should they jump prematurely to assisted reproduction techniques, which can be invasive, difficult, costly, and, at times, counterproductive. Instead, conservation practitioners should first look to nature for guidance, and replicate key conditions found in nature in the captive environment, according to the ecological and behavioral requirements of the species. We tested the effect of a natural hibernation regime on reproductive behaviors and health in the critically endangered mountain yellow-legged frog (Rana muscosa). Hibernation had a clear effect on reproductive behavior, manifesting in vocal advertisement signaling, female receptivity, amplexus, and oviposition. These behaviors are critical components of courtship that lead to successful reproduction. Our main finding was that R. muscosa requires a hibernation period for successful reproduction as only hibernated females produced eggs and only hibernated males successfully fertilized eggs. Although hibernation also negatively impacted body condition, it did so without any evident declines in frog health. This dependency on hibernation is not surprising since it is a major component of the conditions that R. muscosa experiences in the wild. Similar approaches to test hypotheses based on mimicking natural ecological conditions should be used in other amphibian conservation breeding programs to ensure that captive assurance colonies can play their role as genetic reservoirs for assurance and reintroduction.
Papers & Reports Anuran site occupancy and species richness as tools for evaluating restoration of a hydrologically-modified landscape
Authors: Susan C Walls; J Hardin Waddle; William J Barichivich; Ian A Bartoszek; Mary E Brown; J M Hefner; M J Schuman
Date: 2014-06-14 | Outlet: Wetlands Ecology and Management 22(6)625-639.
A fundamental goal of wetland restoration is to reinstate pre-disturbance hydrological conditions to degraded landscapes, facilitating recolonization by native species and the production of resilient, functional ecosystems. To evaluate restoration success, baseline conditions need to be determined and a reference target needs to be established that will serve as an ecological blueprint in the restoration process. During the summer wet seasons of 2010 and 2011, we used automated recording units to monitor a community of calling anuran amphibians in the Picayune Strand State Forest of southwest Florida, USA. This area is undergoing hydrological restoration as part of the Comprehensive Everglades Restoration Plan (CERP). We compared occurrence of anurans at sites in the restoration area, to nearby sites in relatively undisturbed habitat. We assessed the utility of the latter as restoration targets, using a hierarchical model of community species occupancy to estimate the probability of occurrence of anurans in restoration and reference locations. We detected 14 species, 13 of which were significantly more likely to occur in reference areas. All 14 species were estimated by our model to occur at these sites but, across both years, only 8–13 species were estimated to occur at restoration sites. The composition and structure of these habitats within and adjacent to the Picayune Strand State Forest indicate that they are suitable targets for habitat restoration, as measured by amphibian occurrence and species richness. These areas are important sources for recolonization of anuran amphibians as the hydrologically degraded Picayune Strand undergoes restoration to mitigate the effects of overdrainage and habitat loss.
Papers & Reports Breeding site heterogeneity reduces variability in frog recruitment and population dynamics
Authors: Rebecca M McCaffery; Lisa A Eby; B A Maxell; P S Corn
Date: 2014 | Outlet: Biological Conservation 170:169-176
Environmental stochasticity can have profound effects on the dynamics and viability of wild populations, and habitat heterogeneity provides one mechanism by which populations may be buffered against the negative effects of environmental fluctuations. Heterogeneity in breeding pond hydroperiod across the landscape may allow amphibian populations to persist despite variable interannual precipitation. We examined recruitment dynamics over 10 yr in a high elevation Columbia spotted frog (Rana luteiventris) population that breeds in ponds with a variety of hydroperiods. We combined these data with matrix population models to quantify the consequences of heterogeneity in pond hydroperiod on net recruitment (i.e. number of metamorphs produced) and population growth rates. We compared our heterogeneous system to hypothetical homogeneous environments with (1) only ephemeral ponds, (2) only semi-permanent ponds, and (3) only permanent ponds. We also examined the effect of breeding pond habitat loss on population growth rates. Most eggs were laid in permanent ponds each year, but survival to metamorphosis was highest in the semi-permanent ponds. Recruitment success varied by both year and pond type. Net recruitment and stochastic population growth rate were highest under a scenario with homogeneous semi-permanent ponds, but variability in recruitment was lowest in the scenario with the observed heterogeneity in hydroperiods. Loss of pond habitat decreased population growth rate, with greater decreases associated with loss of permanent and semi-permanent habitat. The presence of a diversity of pond hydroperiods on the landscape will influence population dynamics, including reducing variability in recruitment in an uncertain climatic future.
Papers & Reports Modeling structured population dynamics using data from unmarked individuals
Authors: E F Zipkin; J T Thorson; K See; H J Lynch; Evan HC Grant; Y Kanno; R B Chandler; B H Letcher; J A Royle
Outlet: Ecology
The study of population dynamics requires unbiased, precise estimates of
abundance and vital rates that account for the demographic structure inherent in all wildlife
and plant populations. Traditionally, these estimates have only been available through
approaches that rely on intensive capture–recapture data. We extended recently developed Nmixture
models to demonstrate how demographic parameters and abundance can be estimated
for structured populations using only stage-structured count data. Our modeling framework
can be used to make reliable inferences on abundance as well as recruitment, immigration,
stage-specific survival, and detection rates during sampling. We present a range of simulations
to illustrate the data requirements, including the number of years and locations necessary for
accurate and precise parameter estimates. We apply our modeling framework to a population
of northern dusky salamanders (Desmognathus fuscus) in the mid-Atlantic region (USA) and
find that the population is unexpectedly declining. Our approach represents a valuable
advance in the estimation of population dynamics using multistate data from unmarked
individuals and should additionally be useful in the development of integrated models that
combine data from intensive (e.g., capture–recapture) and extensive (e.g., counts) data
sources.
Papers & Reports ARMI 2012 Annual Update
Authors: Blake R Hossack; Michael J Adams; J Hardin Waddle; Evan HC Grant; Robert N Fisher; William A Battaglin; Lianne Ball
Welcome to the 2012 ARMI Annual Update, which provides highlights and significant milestones of this innovative program. ARMI is uniquely qualified to provide research and monitoring results that are scalable from local to national levels and are useful to resource managers. ARMI has produced more than 420 peer-reviewed publications since its inception. Some of those publications are highlighted in this fact sheet. Please visit our website (http://armi.usgs.gov) for additional information on ARMI products, to find summaries of research topics, to search for ARMI activities in your area, or to obtain amphibian photographs. This year, we introduced a new feature on the ARMI website called “Trend Data” that provides occupancy and abundance estimates at the project level (armi.usgs.gov/projects/estimates_datasets.php). Data can be accessed in tabular format or plotted via an interactive map.

Full text: armi.usgs.gov/docs/ARMI%202012%20Annual%20Update.pdf
Papers & Reports ARMI 2011 Annual Update
Authors: Michael J Adams; Erin Muths; Evan HC Grant; David AW Miller; J Hardin Waddle; Susan C Walls; Lianne Ball
Welcome to the inaugural issue of ARMI’s Annual Update. This update provides highlights and significant milestones of this innovative program. ARMI is uniquely qualified to provide research and monitoring results that are scalable from local to national levels, and are useful to resource managers. ARMI has produced nearly 400 peer-reviewed publications, including 18 in 2011. Some of those publications are highlighted in this fact sheet. ARMI also has a new Website (http://armi.usgs.gov). You can now use it to explore an up-to-date list of ARMI products, to find summaries of research topics, to search for ARMI activities in your area, and to obtain amphibian photographs. ARMI’s annual meeting was organized by Walt Sadinski, Upper Midwest Environmental Science Center, and held in St Louis, Missouri. We met with local scientists and managers in herpetology and were given a tour of the herpetology collection at the St. Louis Zoo.

Full text: armi.usgs.gov/docs/ARMI%202011%20Annual%20Update.pdf (PDF*)
Papers & Reports Amphibians in the climate vice: loss and restoration of relilience of montane wetland ecosystems of the American West
Authors: Maureen E Ryan; W J Palen; Michael J Adams; R M Rochefort
Date: 2014-05-01 | Outlet: Frontiers in Ecology and the Environment 12:232-240
Wetlands in the remote mountains of the American West are the site of two massive ecological “experiments” spanning the 20th Century. In a kind of biological carpet-bombing following World War II, fish and wildlife managers introduced millions of predatory trout into fishless mountain ponds and lakes across the Western United States. The new top predators, which now occupy 95% of large mountain lakes, have truncated the habitat distributions of native frogs, salamanders, and wetland invertebrates to smaller, more ephemeral ponds where fish do not survive. Now a second “experiment” –anthropogenic climate change – threatens to push from the opposite direction; eliminating many ephemeral habitats and shortening wetland hydroperiods. Caught between climate-induced habitat loss and predation from introduced fish, native mountain lake fauna of the American West – especially amphibians– are at risk of being squeezed out. Targeted fish removals, guided by models of wetlands change, provide new strategies for restoring resilience.
Papers & Reports Wetland Reserve Program enhances site occupancy and species richness in assemblages of anuran amphibians in the Lower Mississippi Valley, USA
Authors: Susan C Walls; J Hardin Waddle; S Faulkner
Date: 2013-12-03 | Outlet: Wetlands 34:197-207
We measured amphibian habitat use to quantify the effectiveness of conservation practices implemented under the Wetland Reserve Program (WRP), an initiative of the U.S. Department of Agriculture’s (USDA) Natural Resources Conservation Service (NRCS). From February to June 2007, we monitored quantified calling male anurans at sites that were in 1) cultivated cropland. cultivation; 2) formerly in agriculture cultivated cropland but but later restored through the WRP; and mature bottomland hardwood forest. Sites were, all located in two watersheds within the Mississippi Alluvial Valley of Arkansas and Louisiana, USA. We estimated estimated detection probability probabilities of detection and site occupancy within each land use category using a Bayesian hierarchical model of community species occurrence, and derived an estimate of species richness at each site. Relative to agricultural sites, nine of 1l species detected were significantly more likely to occur at WRP sites and six were more likely to occur at forested sites. Derived estimates of species richness were also higher for WRP and forested sites, compared to those in cultivated cropland. Almost half (45%) of the species responded positively to both WRP and forested sites, suggesting indicating that patches undergoing restoration may be an important transitional habitats. Thus, WRP conservation practices are successful in restoring suitable habitat and reducing the impact of cultivation-induced habitat loss on amphibians in the Mississippi Alluvial Valley.
Papers & Reports Assessing the terrestrial movement patterns and habitat preferences of the common toad (Bufo bufo) in a montane area of Central Spain
Authors: D av D; Erin Muths; B os J
Date: 2012 | Outlet: Journal of Herpetology
Widespread amphibian declines and habitat fragmentation, coupled with advancements in tracking technology, have sparked increased emphasis on studying movements and the use of terrestrial habitats by amphibians. Peñalara Natural Park, Sierra de Guadarrama, Central Spain, provides habitat for a number of amphibians that use upland sites. In response to increased pressure on habitat in this region by tourism, we used 4 months of radio telemetry data for 17 adult Common Toads (Bufo bufo) to characterize the terrestrial movements, assess the factors influencing these movements, and determine the distribution and cover characteristics of summer refugia for these toads. We found that: a) movements were most pronounced following the breeding season in June and adults made movements of up to 470 m away from breeding sites, b) movements were not influenced by basin size, climatic variables or the sex the individual, c) the amount of terrestrial habitat used by toads ranged from 245 m2 to 2.5 ha, and d) within these areas toads most often used rock piles and juniper patches (Juniper communis nana) as cover during the summer. Our study emphasizes the importance of considering terrestrial landscapes when developing conservation strategies, and we suggest that a buffer of minimal development extending 550 m from the shoreline of each natal pond be considered when conservation plans are developed for Common Toad habitat in Peñalara.
Papers & Reports COMPARATIVE MICROHABITAT CHARACTERISTICS AT OVIPOSITON SITES OF THE CALIFORNIA RED-LEGGED FROG (RANA DRAYTONII)
Authors: Jeff A Alvarez; D G Cook; J L Yee; Michael G van Hattem; D R Fong; Robert N Fisher
Date: 2013-12-31 | Outlet: Herpetological Conservation and Biology
We studied the microhabitat characteristics of 747 egg masses of the federallythreatened California Red-legged Frog (Rana draytonii) at eight sites in California. Our study showed that a broad range of aquatic habitats are utilized by ovipositing R. draytonii, including sites with perennial and ephemeral water sources, natural and constructed wetlands, lentic and lotic hydrology, and sites surrounded by protected lands and nested within modified urban areas. We recorded 45 different egg mass attachment types, although the use of only a few types was common at each site. These attachment types ranged from branches and roots of riparian trees, emergent and submergent wetland vegetation, flooded upland grassland/ruderal vegetation, and debris. Eggs were deposited in relatively shallow water (mean 39.7 cm) when compared to maximum site depths. We found that most frogs in artificial pond, natural creek, and artificial channel habitats deposited egg masses within one meter of the shore, while egg masses in a seasonal marsh averaged 27.3 m from the shore due to extensive emergent vegetation. Rana draytonii appeared to delay breeding in lotic habitats and in more inland sites compared to lentic habitats and coastal sites. Eggs occurred as early as mid-December at a coastal artificial pond and as late as mid-April in an inland natural creek. We speculate that this delay in breeding may represent a method of avoiding high-flow events and/or freezing temperatures. Understanding the factors related to the reproductive needs of this species can contribute to creating, managing, or preserving appropriate habitat, and promoting species recovery.
Papers & Reports Co-Occurrence of Invasive Cuban Treefrogs and Native Treefrogs in PVC Pipe Refugia
Authors: L M Elston; J Hardin Waddle; Kenneth G Rice; H F Percival
Date: 2013 | Outlet: Herpetological Review 44:406-409
Papers & Reports RANA DRAYTONII (California Red-legged Frog). UNUSUAL DEATH
Authors: Adam R Backlin; Katherine L Baumberger
Date: 2013 | Outlet: Herpetological Review
While conducting monitoring surveys on February 26, 2013 at the southernmost extant population in the USA, an adult male [Rana draytonii] was discovered dead, entangled in several native blackberry ([Rubus ursinus]) vines just below the surface of the water.
Papers & Reports Correction of Locality Records for the Endangered Arroyo Toad (Anaxyrus californicus) from the Desert Region of Southern California
Authors: Edward L Ervin; Kent R Beaman; Robert N Fisher
Date: 2013-12 | Outlet: Bulletin of the Southern California Academy of Sciences
The development of an effective recovery plan for an endangered species requires knowledge of that species distribution and spatial arrangements within preferred habitat. Although the best available information of a species distribution is used to develop a plan, it is often lacking in regard to its actual geographical extent. The arroyo toad (Anaxyrus californicus) occurs in coastal drainages from Monterey County, California, south into northwestern Baja California, Mexico. Through field reconnaissance and the study of museum specimens, we determined that the four reported populations of the arroyo toad in the Sonoran Desert region of Riverside, San Diego, and Imperial counties, California are in error. Two additional sites in the Sonoran Desert are discussed regarding the possibility that the species occurs there. We recommend the continued study of arroyo toad populations in order to establish a better understanding of their distribution and the boundaries of their geographical range.
Papers & Reports Evolutionary Hotspots in the Mojave Desert
Authors: A G Vandergast; R D Inman; Kelly R Barr; K E Nussear; T C Esque; Stacie A Hathaway; D A Wood; P A Medica; Jesse W Breinholt; C L Stephen; A D Gottscho; S B Marks; W B Jennings; Robert N Fisher
Date: 2013-04-15 | Outlet: Diversity 5:293-319
Genetic diversity within species provides the raw material for adaptation and evolution. Just as regions of high species diversity are conservation targets, identifying regions containing high genetic diversity and divergence within and among populations may be important to protect future evolutionary potential. When multiple co-distributed species show spatial overlap in high genetic diversity and divergence, these regions can be considered evolutionary hotspots. We mapped spatial population genetic structure for 17 animal species across the Mojave Desert, USA. We analyzed these in concurrence and located 10 regions of high genetic diversity, divergence or both among species. These were mainly concentrated along the western and southern boundaries where ecotones between mountain, grassland and desert habitat are prevalent, and along the Colorado River. We evaluated the extent to which these hotspots overlapped protected lands and utility-scale renewable energy development projects of the Bureau of Land Management. While 30–40% of the total hotspot area was categorized as protected, between 3–7% overlapped with proposed renewable energy project footprints, and up to 17% overlapped with project footprints combined with transmission corridors. Overlap of evolutionary hotspots with renewable energy development mainly occurred in 6 of the 10 identified hotspots. Resulting GIS-based maps can be incorporated into ongoing landscape planning efforts and highlight specific regions where further investigation of impacts to population persistence and genetic connectivity may be warranted.
Papers & Reports Comparative phylogeography reveals deep lineages and regional evolutionary hotspots in the Mojave and Sonoran Deserts
Authors: D A Wood; A G Vandergast; Kelly R Barr; R D Inman; T C Esque; K E Nussear; Robert N Fisher
Date: 2012 | Outlet: Diversity and Distributions 19:722-737
Aim We explored lineage diversification within desert-dwelling fauna. Our goals were (1) to determine whether phylogenetic lineages and population expansions were consistent with younger Pleistocene climate fluctuation hypotheses or much older events predicted by pre-Pleistocene vicariance hypotheses, (2) to assess concordance in spatial patterns of genetic divergence and diversity among species and (3) to identify regional evolutionary hotspots of divergence and diversity and assess their conservation status.
Location Mojave, Colorado, and Sonoran Deserts, USA.
Methods We analysed previously published gene sequence data for twelve species. We used Bayesian gene tree methods to estimate lineages and divergence times. Within each lineage, we tested for population expansion and age of expansion using coalescent approaches. We mapped interpopulation genetic divergence and intra-population genetic diversity in a GIS to identify hotspots of highest genetic divergence and diversity and to assess whether protected lands overlapped with evolutionary hotspots.
Results In seven of the 12 species, lineage divergence substantially predated the Pleistocene. Historical population expansion was found in eight species, but expansion events postdated the Last Glacial Maximum (LGM) in only four. For all species assessed, six hotspots of high genetic divergence and diversity were concentrated in the Colorado Desert, along the Colorado River and in the Mojave/Sonoran ecotone. At least some proportion of the land within each recovered hotspot was categorized as protected, yet four of the six also overlapped with major areas of human development.
Main conclusions Most of the species studied here diversified into distinct Mojave and Sonoran lineages prior to the LGM – supporting older diversification hypotheses. Several evolutionary hotspots were recovered but are not strategically paired with areas of protected land. Long-term preservation of species-level biodiversity would entail selecting areas for protection in Mojave and Sonoran Deserts to retain divergent genetic diversity and ensure connectedness across environmental gradients.
Papers & Reports Population-level thermal performance of a cold-water ectotherm is linked to ontogeny and local environmental heterogeneity
Authors: Blake R Hossack; W H Lowe; M AH Webb; M J Talbott; K M Kappenman; P S Corn
Date: 2013-11 | Outlet: Freshwater Biology 58:2215-2225
1. Negative effects of global warming are predicted to be most severe for species that occupy a narrow range of temperatures, have limited dispersal abilities, or have long generation times. These are characteristics typical of many species that occupy small, cold streams.
2. Habitat use, vulnerabilities and mechanisms for coping with local conditions can differ among populations and ontogentically within populations, potentially affecting species-level responses to climate change. However, we still have little knowledge of mean thermal performance for many vertebrates, let alone variation in performance among populations. Assessment of these sources of variation in thermal performance is critical for projecting the effects of climate change on species and for identifying management strategies to ameliorate its effects.
3. To gauge how populations of the Rocky Mountain tailed frog (Ascaphus montanus) might respond to long-term effects of climate change, we measured the ability of tadpoles from six populations in Glacier National Park (Montana, USA) to acclimate to a range of temperatures. We compared survival among populations according to tadpole age (age 1-yr or 2-yr) and according to the mean and variance of late-summer temperatures in natal streams.
4. The ability of tadpoles to acclimate to warm temperatures increased with age and with variance in late-summer temperature of natal streams. Moreover, performance differed among populations from the same catchment.
5. Our experiments with a cold-water species show that population-level performance varies across small geographic scales and is linked to local environmental heterogeneity. This variation could influence the rate and mode of species-level responses to climate change, both by facilitating local persistence in the face of changes in thermal conditions, and by providing thermally-tolerant colonists to neighbouring populations.
Papers & Reports Monitoring and managing declines in an amphibian community
Authors: Evan HC Grant; E F Zipkin; J D Nichols; J P Campbell
Date: 2013 | Outlet: Conservatoin
Although many taxa have declined globally, conservation actions are inherently local. Ecosystems degrade even in protected areas, and maintaining natural systems in a desired condition may require active management. Implementing management decisions under uncertainty requires a logical and transparent process to identify objectives, develop management actions, formulate system models linking actions with objectives, monitor to reduce uncertainty and identify system state (i.e., xxx [define system state parenthetically]), and determine an optimal management strategy. We applied one such structured decision-making approach that incorporates these critical elements to inform management of amphibian populations in a protected area. Climate change is expected to affect amphibian occupancy of wetlands and to increase uncertainty in management decision making. We used the tools of structured decision making to identify short-term management solutions that incorporate our current understanding of the effect of climate change on amphibians, emphasizing how management can be undertaken even with incomplete information. .
Papers & Reports Effects of natural flooding and trapping on the facilitation of invasive crayfish-native amphibian coexistence in a semi-arid perennial stream.
Authors: L B Kats; G Bucciarelli; T L Vandergon; R L Honeycutt; E Mattiasen; A Sanders; Seth PD Riley; J L Kerby; Robert N Fisher
Date: 2013-09 | Outlet: Journal of Arid Environments 98:109-112
Aquatic amphibians are known to be vulnerable to a myriad of invasive predators. Invasive crayfish are thought to have eliminated native populations of amphibians in some streams in the semi-arid Santa Monica Mountains of southern California. Despite their toxic skin secretions that defend them from native predators, newts are vulnerable to crayfish attacks, and crayfish have been observed attacking adult newts, eating newt egg masses and larvae. For 15 years we have observed invasive crayfish and native California newts coexisting in one stream in the Santa Monica Mountains. During that period we monitored the densities of both crayfish and newt egg mass densities and compared these to annual rainfall totals. After three seasons of below average rainfall, we reduced crayfish numbers by manual trapping. Our long-term data suggest that crayfish do not fare well in years when rainfall is above the historic average. This invasive predator did not evolve with high velocity streams and observations suggest southern California storm events wash crayfish downstream, killing many of them. Newts exhibit increased reproduction in years when crayfish numbers are reduced. A comparison with a nearby stream that does not contain crayfish suggests that newt reproduction positively responds to increased rainfall, but that fluctuations are much greater in the stream that contains crayfish. We suggest that rainfall patterns help explain invasive crayfish/newt coexistence and that management for future coexistence may benefit from manual trapping.