11 research outputs found
User Interaction Templates for the Design of Lifelogging Systems
No abstract available
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Saving all the pieces: An inadequate conservation strategy for an endangered amphibian in an urbanizing area
Species conservation often focuses on preserving populations on remnant habitat patches, typically without evidence that this approach is sufficient for halting declines. We employed a 19-year dataset to examine the adequacy of this approach for recovering the Sonoma County distinct population segment of California tiger salamanders (SCTS; Ambystoma californiense), California, USA, which now exists almost entirely in remnant habitat patches designated as preserves across a rapidly urbanizing landscape. We estimated relative SCTS larval densities from standardized annual surveys from 2002 to 2020 across 118 vernal pools in eight preserves. We found that relative larval SCTS densities decreased by 48% over the study period, indicating that current efforts to conserve SCTS are inadequate for long-term viability. Increased densities were only observed at the single study preserve where SCTS were introduced. Temporal trends in larval density among preserves were best explained by the number of pools available to SCTS, and the ability of breeding pools to retain water throughout the larval period. Specifically, preserves with >1 breeding pool and ≥1 breeding pool that held water for at least two months following the breeding season (into late April) even in dry years had substantially lower rates of larval decline. Active conservation management of preserves, including provision of multiple breeding pools, at least some of which are resilient to variable future precipitation regimes, will be required to effectively conserve SCTS. We expect these findings to apply broadly to the conservation of many species of pool-breeding amphibians
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Habitat value of constructed breeding pools for the endangered Sonoma population of California tiger salamander
Habitat creation is a common element of efforts to recover populations threatened by altered habitat. Unfortunately, human-created habitats do not necessarily support re-establishment of target species. We investigated the value of constructed vernal pools as breeding habitat for the endangered Sonoma County population of California tiger salamanders (Ambystoma californiense) by conducting 19 years of larval surveys in 118 pools that were natural (n = 40), constructed (n = 70), or natural with substantial human alterations (human-altered, n = 8). California tiger salamander larval densities in human-altered and natural pools declined over the study period, while larval densities in constructed pools showed non-negative trends. Larval declines in natural pools may be attributed to long-term degradation of the surrounding terrestrial habitat. Mean larval densities over the course of the study were equivalent between constructed and natural pools, when corrected for pool morphometry. In contrast, human-altered pools had lower larval densities. To assure consistent California tiger salamander breeding, pools needed to be >= 30 cm deep and 240 m(2) in area, with deeper (50-70 cm) and larger (1,600-1,800 m(2)) pools providing increased larval productivity. Over the study, there was no evidence of decrease in the rate of colonization of new pools. We conclude that constructed pools can be important tools in the recovery of imperiled pool-breeding amphibians if proper design elements for the target species are considered
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Applying stochastic and Bayesian integral projection modeling to amphibian population viability analysis
Integral projection models (IPMs) can estimate the population dynamics of species for which both discrete life stages and continuous variables influence demographic rates. Stochastic IPMs for imperiled species, in turn, can facilitate population viability analyses (PVAs) to guide conservation decision-making. Biphasic amphibians are globally distributed, often highly imperiled, and ecologically well suited to the IPM approach. Herein, we present a stochastic size- and stage-structured IPM for a biphasic amphibian, the U.S. federally threatened California tiger salamander (CTS) (Ambystoma californiense). This Bayesian model reveals that CTS population dynamics show greatest elasticity to changes in juvenile and metamorph growth and that populations are likely to experience rapid growth at low density. We integrated this IPM with climatic drivers of CTS demography to develop a PVA and examined CTS extinction risk under the primary threats of habitat loss and climate change. The PVA indicated that long-term viability is possible with surprisingly high (20%-50%) terrestrial mortality but simultaneously identified likely minimum terrestrial buffer requirements of 600-1000 m while accounting for numerous parameter uncertainties through the Bayesian framework. These analyses underscore the value of stochastic and Bayesian IPMs for understanding both climate-dependent taxa and those with cryptic life histories (e.g., biphasic amphibians) in service of ecological discovery and biodiversity conservation. In addition to providing guidance for CTS recovery, the contributed IPM and PVA supply a framework for applying these tools to investigations of ecologically similar species