Geology topics

Research about Pinnacles National Park

Source-linked reports with geographic coverage including Pinnacles National Park.

3 recordsLinked to original sources

USGS2026

Conducting feasibility assessments of potential conservation reintroductions: A case study with the imperiled foothill yellow-legged frog, Rana boylii

Conservation translocations are an increasingly common and often necessary component of recovering species that have become extirpated from portions of their range. Understanding and ameliorating potential threats that reduce the likelihood of successful population establishment at recipient sites is a key component of successful translocation planning. We examined multiple potential threats, including pathogens, contaminants, and invasive species, as well as habitat suitability and food resources, to assess the feasibility of reintroducing threatened, stream-obligate foothill yellow-legged frogs, Rana boylii , to Pinnacles National Park. Foothill yellow-legged frogs were extirpated from this protected area more than half a century ago. Although invasive species, disease, contaminants, food resources, and water temperatures are unlikely to inhibit foothill yellow-legged frog population establishment, potential recipient streams at Pinnacles National Park had shorter hydroperiods and much higher canopy cover than reference streams with extant foothill yellow-legged frog populations. Although the exact cause of extirpation of foothill yellow-legged frogs from Pinnacles National Park is unknown, translocations of foothill yellow-legged frogs to the park are more likely to succeed if riparian canopy cover is reduced and stream hydroperiods increased to better match those at nearby populations. Thoroughly understanding the threats to and characteristics of potential recipient sites could improve the likelihood of success of translocation outcomes in natural areas.

California↗

USGS2022

Aqueous geochemistry of waters and hydrogeology of alluvial deposits, Pinnacles National Park, California

A cooperative study between the National Park Service (NPS) and the U.S. Geological Survey (USGS) characterized groundwater quality and hydrogeology in parts of Pinnacles National Park. The water-quality investigation assessed the geochemistry of springs, wells, surface water, and precipitation and analyzed geochemistry of rock formations that affect the water chemistry through water-rock interaction. The hydrogeology investigation used geophysical and groundwater level data to characterize groundwater-flow processes in the alluvial deposits of Bear Valley and the Chalone Creek watershed. Analysis of aqueous geochemical parameters in water samples from perennial springs, water-supply wells, and surface waters was conducted for samples collected after the dry season (autumnal) and after the wet season (vernal) to assess changes in geochemistry due to changes in groundwater levels or flow resulting from precipitation. The chemistry of bulk precipitation collected during the wet season was also analyzed. Bedrock samples were analyzed for geochemical parameters to help constrain groundwater sources, flow paths, and weathering. The geochemical investigations show a correspondence between the source rock and the spring-water chemistry that can be attributed to the mineralogy of the source rock. The narrow range of strontium isotopes in water samples, sourced in geochemically and mineralogically disparate rocks, indicates that the bedrock groundwater is relatively old and has reached quasi-steady state with respect to weathering of susceptible minerals. Groundwater-level monitoring indicated that the water table is shallow—from 0 to 10 meters (m) below land surface. In southern Bear Valley and in the Chalone Creek alluvium, water levels rose and declined by several meters over each annual cycle of this study. In northern Bear Valley, water levels rose modestly over two wet seasons but declined during a third wet season. In Bear Valley, groundwater/surface-water interaction occurs along the perennial reach of Sandy Creek. Groundwater discharges to the upstream part of the reach, becomes surface water and is partly consumed by evapotranspiration, and infiltrates farther downstream. In the Chalone Creek alluvium, runoff-generated surface-water flow in intermittent stream reaches is a major component of groundwater recharge. After the onset of significant streamflow, creek water rapidly recharges groundwater until water levels rise to nearly the creek level. Groundwater levels generally remain high throughout the wet season, then gradually decline after the creek becomes dry.

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USGS2022

Collateral damage: Anticoagulant rodenticides pose threats to California condors

Anticoagulant rodenticides (ARs) are widespread environmental contaminants that pose risks to scavenging birds because they routinely occur within their prey and can cause secondary poisoning. However, little is known about AR exposure in one of the rarest avian scavengers in the world, the California condor ( Gymnogyps californianus ). We assessed AR exposure in California condors and surrogate turkey vultures ( Cathartes aura ) to gauge potential hazard to a proposed future condor flock by determining how application rate and environmental factors influence exposure. Additionally, we examined whether ARs might be correlated with prolonged blood clotting time and potential mortality in condors. Only second-generation ARs (SGARs) were detected, and exposure was detected in all condor flocks. Liver AR residues were detected in 42% of the condors (27 of 65) and 93% of the turkey vultures (66 of 71). Although concentrations were generally low (<10 ng/g ww), 48% of the California condors and 64% of the turkey vultures exposed to ARs exceeded the 5% probability of exhibiting signs of toxicosis (>20 ng/g ww), and 10% and 13% exceeded the 20% probability of exhibiting signs toxicosis (>80 ng/g ww). There was evidence of prolonged blood clotting time in 16% of the free-flying condors. For condors, there was a relationship between the interaction of AR exposure index (legal use across regions where condors existed) and precipitation, and the probability of detecting ARs in liver. Exposure to ARs may complicate recovery efforts of condor populations within their current range and in the soon to be established northern California experimental population. Continued monitoring of AR exposure using plasma blood clotting assays and residue analysis would allow for an improved understanding of their hazard to condors, particularly if paired with recent movement data that could elucidate exposure sources on the landscape occupied by this endangered species.

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