Geology topics

Michael Weber

Publications and source records attributed to Michael Weber.

5 recordsLinked to original sources

USGS2025

Power source, data retrieval method, and attachment type affect success of dorsally mounted tracking tag deployments in 37 species of shorebirds

Animal-borne trackers are commonly used to study bird movements, including in long-distance migrants such as shorebirds. Selecting a tracker and attachment method can be daunting, and methodological advancements often have been made by trial and error and conveyed by word of mouth. We synthesized tracking outcomes across 2745 dorsally mounted trackers on 37 shorebird species around the world. We evaluated how attachment method, power source, data retrieval method, relative tracker mass, and biological traits affected success, where success was defined as whether or not each tag deployment reached its expected tracking duration (i.e. all aspects succeeded for the intended duration of the study: attachment, tracking, data acquisition, and bird survival). We conducted separate analyses for tag deployments with remote data retrieval (‘remote-upload tag deployments') and those that archived data and had to be recovered (‘archival tag deployments'). Among remote-upload tag deployments, those that were a lighter mass relative to the bird, were beyond their first year of production, transmitted data via satellite, or were attached with a leg-loop harness were most often successful at reaching their expected tracking duration. Archival tag deployments were most successful when applied at breeding areas, or when applied to males in any season. Remote-upload tag deployments with solar power, satellite data retrieval, or leg-loop harnesses continued tracking for longer than those with battery power, other types of data retrieval, or glue attachments. However, the majority of tag deployments failed to reach their expected tracking duration (71% of remote-upload, 83% of archival), which could have been due to tracker failure, attachment failure, or bird mortality. Our findings highlight that many tag deployments may fail to meet the goals of a study if tracking duration is crucial. Using our results, we provide guidelines for selecting a tracker and attachment to improve success at meeting study goals.

Journal of Avian Biology↗

USGS2024

Return rates of GPS-tagged Pacific Golden-Plovers: A controlled study in Hawaii

In a study of GPS-tagged Pacific Golden-Plovers wintering at Moorea, French Polynesia, Johnson et al. (2020) raised questions about possible tag-induced mortality. Similar concerns in other species have generated considerable attention in recent years. Of 19 tagged plovers that departed Moorea on northward migration, only one bird (5 %) uploaded a complete migratory cycle to Argos. Furthermore, contact was lost with 12 birds (63 %) variously during overwater flight, at stopover sites, or on nesting grounds; and no signals at all were received from 6 individuals (32%). Such observations suggest that carrying a tag might be a life-threatening burden. We cannot exclude the possibility that tag weight caused difficulties for the Moorea birds. However, this seems an unlikely factor in that the device (tag plus harness) being carried weighed less than 3 % of body mass (see beyond). Such a load is in accord with generally accepted albeit arbitrary limits. Other tag-associated concerns such as altered aerodynamics, increased vulnerability to predation, and (given the complex nature of geomagnetic navigation, the possibility that tag electronics might interfere with sense of direction, are more difficult to evaluate. Alternatively, loss of contact with tagged birds may be simply a matter of tag malfunction, battery failure, or a broken harness. To shed light on these uncertainties, and to explore the survival of GPS-tagged plovers on a nonbreeding ground in Hawaii, we conducted a controlled study using birds that winter in the National Memorial Cemetery of the Pacific (known locally as the Punchbowl).

Hawaii↗

USGS2023

Synthesizing professional opinion and published science to build a conceptual model of Walleye recruitment

Understanding and predicting recruitment, longstanding goals in fisheries science and ecology, are complicated by variation in the importance of environmental drivers coupled with the dynamic nature of individual ecosystems. Developing an understanding of recruitment from well-monitored stocks offers an opportunity to overcome these complexities. We used a systematic literature review, a survey, and a workshop attended by professionals with expertise in recruitment of Walleye Sander vitreus to identify common environmental drivers of Walleye recruitment and additional sources of variation (i.e., context dependencies) among populations. The importance of individual environmental drivers, as well as the direction of their influence, differed as a function of geographic region, lake surface area, and Walleye life stage. The literature suggested abiotic conditions (e.g., temperature) during the first year of life were influential in determining recruitment. Professional opinion noted the importance of biotic factors, with prey availability and predation risk having the most consistent relationships with recruitment. We synthesized this information to propose a conceptual model that illustrates the suite of characteristics that shape Walleye recruitment over large spatial and temporal scales. Our findings emphasize the importance of first-year growth and system-specific contextual factors, which can alter the relative importance of the environmental drivers of recruitment.

Fisheries Magazine↗

USGS2019

A General Lake Model (GLM 3.0) for linking with high-frequency sensor data from the Global Lake Ecological Observatory Network (GLEON)

The General Lake Model (GLM) is a one-dimensional open-source code designed to simulate the hydrodynamics of lakes, reservoirs, and wetlands. GLM was developed to support the science needs of the Global Lake Ecological Observatory Network (GLEON), a network of researchers using sensors to understand lake functioning and address questions about how lakes around the world respond to climate and land use change. The scale and diversity of lake types, locations, and sizes, and the expanding observational datasets created the need for a robust community model of lake dynamics with sufficient flexibility to accommodate a range of scientific and management questions relevant to the GLEON community. This paper summarizes the scientific basis and numerical implementation of the model algorithms, including details of sub-models that simulate surface heat exchange and ice cover dynamics, vertical mixing, and inflow–outflow dynamics. We demonstrate the suitability of the model for different lake types that vary substantially in their morphology, hydrology, and climatic conditions. GLM supports a dynamic coupling with biogeochemical and ecological modelling libraries for integrated simulations of water quality and ecosystem health, and options for integration with other environmental models are outlined. Finally, we discuss utilities for the analysis of model outputs and uncertainty assessments, model operation within a distributed cloud-computing environment, and as a tool to support the learning of network participants.

Geoscientific Model Development↗

USGS2018

A case study and a meta-analysis of seasonal variation in fish mercury concentrations

Mercury contamination in aquatic ecosystems is a concern due to health risks of consuming fish. Fish mercury concentrations are highly variable and influenced by a range of environmental factors. However, seasonal variation in mercury levels are typically overlooked when monitoring fish mercury concentrations, establishing consumption advisories, or creating accumulation models. Temporal variation in sampling could bias mercury concentration estimates of accumulation potential. Thus, the objectives of this study were to first evaluate seasonal variation of largemouth bass ( Micropterus salmoides ) axial muscle mercury concentration from two Iowa, USA impoundments. Second, we conducted a meta-analysis to evaluate if seasonal variation in mercury concentration is dependent upon mean mercury concentration, waterbody type, or fish trophic level or mean length. Largemouth bass were collected four times between May and October (24–36 fish per month) from Twelve Mile (2013) and Red Haw (2014) lakes. Largemouth bass axial muscle mercury concentrations were variable within and between lakes, ranging from undetectable ( < 0.05 mg/kg) to 0.54 mg/kg. Largemouth bass mercury concentrations were similar across months in Twelve Mile but varied temporally in Red Haw and were highest in July, intermediate in May and September, and lowest during October. Results of the meta-analysis suggest that seasonal variation in mercury concentrations is more likely to occur as mean mercury concentration of the population increases but is unrelated to waterbody type, trophic status, and fish size. Understanding seasonal variation in fish mercury concentrations will aid in the development of standardized sampling programs for long-term monitoring programs and fish consumption advisories.

Iowa↗