Animal reintroductions: an innovative assessment of survival
Authors: Muths E, Bailey LL, Watry MK | Date: 2014-06 | Outlet: Biological Conservation xx:xxx-xxx
Quantitative evaluations of reintroductions are infrequent and assessments of milestones reached before a project is completed, or abandoned due to lack of funding, are rare. However, such assessments, which are promoted in adaptive management frameworks, are critical. Quantification can provide defensible estimates of biological success, such as the number of survivors from a released cohort, with associated cost per animal. It is unlikely that the global issues of endangered wildlife and population declines will abate, therefore, assurance colonies and reintroductions are likely to become more common. If such endeavors are to be successful biologically or achieve adequate funding, implementation must be more rigorous and accountable. We use a novel application of a multistate, robust design capture-recapture model to estimate survival of reintroduced tadpoles through metamorphosis (i.e., the number of individuals emerging from the pond) and thereby provide a quantitative measure of effort and success for an “in progress” reintroduction of toads. Our data also suggest that tadpoles released at later developmental stages have an increased probability of survival and that eggs laid in the wild hatched at higher rates than eggs laid by captive toads. We illustrate how an interim assessment can identify problems, highlight successes, and provide information for use in adjusting the effort or implementing a Decision-Theoretic adaptive management strategy.
ARMI 2013 Annual Update
Authors: Halstead BJ, Adams MJ, Grant ECH, Hossack BR, Smalling KL, Ball LC | Date: 2014-02-17 | Format: .PDF
Welcome to the 2013 Annual ARMI Update, which provides highlights and significant milestones of this innovative program. This was an especially notable year for ARMI with the release of a landmark publication “Trends in amphibian occupancy in the United States.” Our synthesis and scaling up of 9 years of monitoring data produced the first-ever estimate of how fast frogs, toads and salamanders in the United States are disappearing from their habitats. Our findings received international attention and rekindled the discussion about global amphibian declines. This was not the only topic we addressed this year, as ARMI’s total publication count rose to 460 papers representing our latest research findings on the effects of climate change, land use, diseases, pesticides, and management on amphibian populations.
Full text: armi.usgs.gov/docs/ARMI%202013%20Annual%20Update.pdf
Modeling structured population dynamics using data from unmarked individuals
Authors: Zipkin, EF, Thorson, JT, See, K, Lynch, HJ, Grant, EHC, Kanno, Y, Chandler, RB, Letcher, BH, Royle, JA | 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
ARMI 2012 Annual Update
Authors: Hossack B, Adams M, Waddle H, Grant E, Fisher R, Battaglin W, Ball L | Format: .PDF
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
ARMI 2011 Annual Update
Authors: Adams M, Muths E, Grant E, Miller DA, Waddle H, Walls S, Ball L | Format: .PDF
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
Assessing the terrestrial movement patterns and habitat preferences of the common toad (Bufo bufo) in a montane area of Central Spain
Authors: D Daversa, E Muths, J Bosch | Date: 2012 | Outlet: Journal of Herpetology | Format: .PDF
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.
COMPARATIVE MICROHABITAT CHARACTERISTICS AT OVIPOSITON SITES OF THE CALIFORNIA RED-LEGGED FROG (RANA DRAYTONII)
Authors: Alvarez JA, Cook DG, Yee JL, van Hattem MG, Fong DR, Fisher RN | Date: 2013-12-31 | Outlet: Herpetological Conservation and Biology | Format: .PDF
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.
Co-Occurrence of Invasive Cuban Treefrogs and Native Treefrogs in PVC Pipe Refugia
Authors: Elston LM, Waddle JH, Rice KG, Percival HF | Date: 2013 | Outlet: Herpetological Review 44:406-409
RANA DRAYTONII (California Red-legged Frog). UNUSUAL DEATH
Authors: Backlin A, Baumberger K | Date: 2013 | Outlet: Herpetological Review | Format: .PDF
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.
Correction of Locality Records for the Endangered Arroyo Toad (Anaxyrus californicus) from the Desert Region of Southern California
Authors: Ervin EL, Beaman KR, Fisher RN | Date: 2013-12 | Outlet: Bulletin of the Southern California Academy of Sciences | Format: .PDF
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.