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Abigail J. Lynch

Publications and source records attributed to Abigail J. Lynch.

At least 37 records · Page 2Linked to original sources
USGS2025

Exposure, sensitivity, or adaptive capacity? Reviewing assessments that use only two of three elements of climate change vulnerability

As climate change accelerates, understanding which species are most vulnerable and why they are vulnerable will be vital to inform conservation action. Climate change vulnerability assessments (CCVAs) are tools to assess species' responses to climate change, detect drivers of vulnerability, and inform conservation planning. CCVAs are commonly composed of three elements: exposure, sensitivity, and adaptive capacity. Incorporating all three elements can be challenging, and including only two of the three elements may be a more feasible approach in many systems. Although two-element CCVA approaches have become more common, their utility and procedures remain poorly documented. We conducted a literature review to explore the scope, methods, and rationale of CCVAs that use a two-element approach to assess vertebrate vulnerability. Despite the potential to expand CCVAs into understudied systems, two-element assessments had similar geographic and taxonomic biases as those previously detected in CCVAs in general. Methods varied, yet we found that variables used in two-element studies could be condensed into standardized categories to enhance comparability. Finally, limitations in data availability and computational resources were common rationales for using a two-element approach. By clarifying the purposes, opportunities, and limitations of two-element assessment, this review can aid in selecting appropriate methods for CCVAs.

Conservation Science and Practice↗
USGS2025

Global recreational consumption of non-native inland fish: Higher economic benefits, but lower nutritional value and climate resilience

Inland recreational fisheries are globally significant leisure pursuits, with well-documented benefits to human health and well-being, but also one of the principal drivers of non-native fish introductions to enhance fishing opportunities, whether for sport or sustenance. In this study, we assess the relative reliance of global inland recreational fisheries on non-native versus native species for harvest. We further examine how this reliance varies by economic and nutritional value as well as the climate vulnerability of the species involved. We demonstrate that, of the 1,325,851 t of inland recreational fishes recreationally harvested for consumption worldwide in 2021, non-native fish were a small proportion (4 %; 53,651 t). On a global scale, non-native fish contributed a net positive 38.2 % economic value to inland recreational harvest. However, they also contributed a net negative −21.9 % nutritional value to inland recreational harvest. Non-native fishes were also more climate vulnerable (i.e., higher average climate vulnerability index values) and thus proportionally increased overall estimates of climate vulnerability with a net positive of 70.9 %. Our results quantitatively demonstrate that non-native species play a more important role in inland consumptive recreational fisheries than their mere harvest volume would suggest. However, many nuances were seen on the continent and country scale, which reflect the complexity of fisher behavior, fish distribution and socio-economic factors. Our findings help unravel the complex effects of non-native species on human activities and underscore the need to evaluate their global impacts holistically.

Science of the Total Environment↗
USGS2025

Integrating the resist–accept–direct framework into natural resource decision-making processes for climate adaptation

The resist–accept–direct (RAD) framework for climate adaptation is a useful tool, particularly when conservation practitioners know they need to address climate change but do not know where to start or when they struggle to implement conservation actions that are outside the status quo. Some conservation practitioners may view RAD as a decision process that will lead them through selecting climate adaptation actions to meet their objectives; however, RAD may be better suited for use with existing decision processes. RAD can improve adaptation planning processes by helping conservation practitioners examine a broader portfolio of climate adaptation actions. Choosing the actions that meet organizational objectives and long-term goals relies on a sound decision process through which to select RAD-generated actions to implement across space and time. The good news for conservation practitioners is that RAD can easily be integrated into the decision processes they are already using—that is, a new decision process for RAD is not necessary. We examined 6 commonly used decision frameworks in the context of RAD for climate adaptation: structured decision-making, adaptive management, conservation standards, climate-smart conservation, strategic habitat conservation, and scenario planning. Each decision framework can easily incorporate RAD methodologies to create climate adaptation menus and portfolios within existing structures, allowing conservation practitioners to continue to utilize existing frameworks for their valuable decision-making tools. Integrating the RAD framework can enhance them by explicitly considering future uncertainties and providing a menu of climate adaptation actions for navigating changing ecosystems.

Conservation Biology↗
USGS2025

Disentangling the historical impacts of warming and fishing on exploited freshwater fish populations

Worldwide, exploited fish populations are increasingly affected by the combined effects of warming and fishing. Disentangling the relative effects of these factors is challenging yet crucial for designing management strategies. We used a temperature-dependent population dynamics model to assess the impacts of lake warming and fishing on 521 freshwater fish populations in the Midwestern United States—a transitional zone between cold- and warmwater species. Overall, most warmwater species (65% of populations) exhibited increases in productivity from warming, while slightly more than half of the cool-/cold-water species (53% of populations) experienced reduced productivity. Populations closer to their carrying capacity showed greater resilience to warming. For the majority of populations (92%), fishing had a more pronounced effect on population dynamics than warming during the time period examined. Therefore, while warming is likely to increasingly threaten many fish populations, effective local fishery management remains a key lever to mitigate these impacts.

Minnesota, Wisconsin↗
USGS2025

Evaluating how changing climate and water clarity can affect restoration of native coregonine fishes in midwestern lakes

In the upper midwestern United States, coregonine fishes (e.g., ciscoes and whitefishes) have provided a key food source for Indigenous peoples since time immemorial. In the last century, however, several anthropogenic stressors including overfishing, declining quality of key habitat (e.g., dams, algal blooms), and negative interactions with invasive species have led to declines in the fisheries that coregonines support. Hence, fishery managers have undertaken steps to conserve existing diversity or re-introduce species that have been locally extirpated. This study assessed the extent to which changes in water clarity and climate pose challenges for conservation of coregonines and sought to provide information to inform management decisions about which populations would be best for reintroduction. Through experiments, we found that a Cisco ( Coregonus artedi ) population at the southern edge of its range had no marked advantages in respiration or thermal tolerance, relative to a northern Great Lake population. This result indicates that the latter population would be a reasonable candidate for reintroduction in Lake Erie, where warming water could be a potential impediment. Other laboratory experiments revealed that Cisco could be vulnerable to increasing ultraviolet radiation (UV; 280 – 320 nm) penetration in lakes due to reduced ice cover and increased water clarity owing to water quality improvements and/or invasive mussel filtration. Our experiments found that UV exposure causes earlier hatching, more irregular pigmentation near the head and yolk-sac region, and reduced heart rate. Therefore, UV could be a heretofore unrealized threat to Cisco populations. Through the completion of additional final products from this project and additional research connecting laboratory and field data together, the extent to which the eggs and larvae of coregonine species could be vulnerable to increased UV associated with increasing water clarity or reduced ice cover will help inform restoration or conservation planning for these fish.

Cooperator Report↗
USGS2024

Lake temperature and morphometry shape the thermal composition of recreational fishing catch

Objective Managing freshwater fisheries in warming lakes is challenging because climate change impacts anglers, fish, and their interactions. Methods We integrated recent models of current and future lake temperatures with recreational fisheries catch data from 587 lakes in three north-central U.S. states (Michigan, Minnesota, and Wisconsin) to evaluate how the thermal composition of recreational fisheries catch varied as a function of temperature, ice coverage, and lake morphometry. Result We found that warmwater catch share (WCS), defined as the proportion of fish in recreational angling catch that belonged to the warmwater thermal guild (final temperature preferendum [FTP] > 25°C), increased with average annual lake surface temperature and decreased with survey ice coverage. However, we also found that WCS decreased with increased lake area and depth. Using mid-century (2040–2060) water temperature and ice projections while holding all other variables constant, we predicted that WCS will likely increase as the climate warms but that significant thermal heterogeneity will persist. Conclusion Lakes that are large (>100 ha) and deep (>10 m) and those with cooler (<3700 annual growing degree-days) predicted future temperatures will likely hold thermal refugia for coolwater (FTP = 19–25°C) and coldwater (FTP < 19°C) fish even as average lake temperatures rise, creating the potential for management actions to resist the shift from coolwater to warmwater fisheries. Managers of smaller and more rapidly warming lakes may want to consider strategies that accept or direct emerging warmwater fishing opportunities. We suggest that the most viable path to climate adaptation in landscapes of diverse lakes may be to resist warmwater shifts where possible and to accept or direct the rise of warmwater fishing opportunities where necessary.

Michigan, Minnesota, Wisconsin↗
USGS2024

Supporting climate adaptation for rural Mekong River Basin communities in Thailand

Climate change impacts on large river basins, such as the Mekong River Basin (MRB), are complex due to shared governance and interconnected socioeconomic areas, making them highly vulnerable to change. The MRB, spanning six countries including Thailand, is crucial for the food and economic security of > 60 million people. However, in 2021, Thailand was ranked as the 9th highest risk country affected by climate change. To integrate climate adaptation in Thailand's MRB, we examined the effects of climate change on rapidly developing farmer and fisher communities in northeastern Thailand and explored feasible adaptation options. Using an interdisciplinary approach that included literature review, participatory action methods, and the resist-accept-direct (RAD) framework, we found that climate change is projected to increase temperatures, precipitation, extreme events, erosion, and water clarity, while decreasing heavy sediment transport. These changes negatively impact agriculture, fisheries, human health, and tourism. We identified several adaptation strategies across environmental, ecological, and human health categories to accommodate local needs, such as preventing habitat degradation (e.g., from dams and deforestation), providing fish refuge and passage, and supporting technical capacity. Community-driven adaptation planning and implementation are essential for supporting global sustainable development in a changing climate.

Mitigation and Adaptation Strategies for Global Ch↗
USGS2024

Computational approaches improve evidence synthesis and inform broad fisheries trends

Addressing ecological impacts with effective conservation actions requires information on the links between human pressures and localized responses. Understanding links is a priority for many conservation contexts, including the world's fresh waters, which face intensifying threats to disproportionately high species diversity, including more than half of the world's fish species. Literature synthesis can uncover links and highlight potential research gaps, yet can be very cumbersome and time consuming. Emerging tools like text mining can improve efficiency in extracting relevant information from vast scientific outputs. This study synthesizes evidence of direct anthropogenic threats to major inland fisheries and examines driver-impact-response patterns using coupled automated and manual text classification methods. We screened 9336 abstracts from 45 river basins of high importance to inland fish production; 1152 abstracts contained evidence of direct threats to fish. The most common documented drivers were pollution, dams, and fishing pressure, which were most strongly linked to decreased fitness, altered reproduction, and mortality, respectively. Strong impact-response links to pollution signal potential bias toward documenting acute threats that generate more visible and immediate impacts. The use of machine learning-based text classification performed best in classifying extraneous information. Results can inform the development of inland fisheries indicators and threat-based metrics, highlight possible evidence gaps in linking global drivers to fishery-level responses, and illustrate the application of a coupled synthesis approach for improved efficiency and extraction of information relevant to conservation outcomes. The associated user and interpretation guides address accessibility and technical barriers faced by conservation scientists to improve efficiency in evidence synthesis.

Conservation Science and Practice↗
USGS2024

The effects of flow extremes on native and non-native stream fishes in Puerto Rico

Globally, freshwater fishes are among the taxa most vulnerable to climate change but are generally understudied in tropical island ecosystems where climate change is predicted to alter the intensity, frequency and duration of extreme flow events. These changes may impact stream ecosystems and native and non-native biota in complex ways. We compiled an extensive dataset of fish assemblages collected at 119 sites across the Caribbean island of Puerto Rico from 2005 to 2015. We coupled these data with stream flow indices and dam height to understand associations between flow and fish assemblage structure. Sixteen percent of sites contained exclusively non-native species, 34% contained exclusively native species, and 50% contained native and non-native species. We built generalised linear models and conducted all subsets model selection to identify extreme flow variables explaining variation in native and non-native species richness and biomass. We also built models to determine the combined effects of extreme flows and the presence of non-native species on native species richness and biomass. Extreme flows and dam height were important in explaining variations in native and non-native species richness and biomass. Model averages showed native biomass decreased by 0.42 kg/ha with a 1-m increase in dam height, by 0.05 kg/ha with 1 cm/s increase in maximum mean daily high flow and by 3.45 kg/ha with each additional day increase in maximum high flow duration, and increased by 2.06 kg/ha with each additional day increase in mean high flow duration. Model averages predicted that non-native biomass increased by 1.32 kg/ha with a 1-m increase in dam height and by 0.01 kg/ha with each additional day increase in mean high flow duration, and decreased by 0.36 kg/ha with each additional day increase in maximum high flow duration. Model averages also predicted an increase in native and non-native biomass of 0.71 gage and 0.06 kg/ha, respectively, with each additional day increase in maximum low flow duration. The combined effects of non-native species presence and extreme flows changed the relationship between maximum high and low flow durations and native biomass. Model averages showed that native biomass increased by 1.83 kg/ha with each additional day increase in maximum high flow duration and decreased by 2.52 kg/ha with each additional day increase in maximum low flow duration when non-native species were present. Native fishes may be able to better cope with longer maximum durations of low flows than expected when non-native fishes are absent. In mixed fish assemblages, extended maximum durations of high flows may act as a control of non-native species and dampen their negative effect on native species, but longer maximum durations of low flows may heighten the negative effects of non-native fishes. Our results are informative for tropical island ecosystems globally and can guide the management and conservation of native fishes, particularly when faced with the dual threats of climate change and non-native species. Managers may consider increasing efforts to conserve native fishes in Caribbean rivers by maintaining connectivity and habitat complexity while preventing non-native species introductions.

Freshwater Biology↗
USGS2024

Inland recreational fisheries contribute nutritional benefits and economic value but are vulnerable to climate change

Inland recreational fishing is primarily considered a leisure-driven activity in freshwaters, yet its harvest can contribute to food systems. Here we estimate that the harvest from inland recreational fishing equates to just over one-tenth of all reported inland fisheries catch globally. The estimated total consumptive use value of inland recreational fish destined for human consumption may reach US$9.95 billion annually. We identify Austria, Canada, Germany and Slovakia as countries above the third quantile for nutrition, economic value and climate vulnerability. These results have important implications for populations dependent on inland recreational fishing for food. Our findings can inform climate adaptation planning for inland recreational fisheries, particularly those not currently managed as food fisheries.

Nature Food↗
USGS2024

Life on land needs fresh water (SDG 15)

Terrestrial ecosystems, such as forests, and the inland waters within them, such as bogs, floodplains, lakes, rivers, springs, and wetlands, are foundational for life on earth. They provide critical ecosystem services such as carbon storage and sequestration, clean water, primary production, pollination, soil fertility, and erosion control. The human footprint on terrestrial and freshwater ecosystems continues to expand, imposing pressures from deforestation, invasive species, climate change, overexploitation of species, and land conversion for agricultural production. The United Nations’ Sustainable Development Goal (SDG) 15 (Life on Land) aims to address these changes by promoting the protection, restoration, and sustainable use of terrestrial ecosystems globally. Freshwater ecosystem services and freshwater biological diversity are inherently part of, and critical to, achieving SDG 15; yet they remain absent from the goal and largely hidden within the targets and indicators. Here, we aim to highlight the role and importance of freshwater ecosystems in achieving SDG 15. We identify the six major themes of SDG 15 in which freshwater ecosystems have a preeminent role: (1) increasing protected areas, (2) sustainably managing forests, (3) reducing land degradation, (4) protecting threatened and trafficked species, (5) reducing invasive species, and (6) mobilizing resources. For each theme, we detail (a) freshwater connections to the topic, (b) key opportunities in addressing freshwater components, and (c) a relevant case study highlighting cobenefits for terrestrial ecosystems from actions targeting freshwater ecosystems. We conclude with opportunities for integrative terrestrial–aquatic monitoring, management, and policy actions. Ultimately, achieving the targets of SDG 15 requires recognition of terrestrial–aquatic interdependencies and prioritization of freshwater ecosystems and biodiversity.

Book chapter↗
USGS2024

Early pandemic recreational fishing patterns across the urban-to-rural gradient in the U.S.

In 2020, the SARS-CoV-2 (COVID-19) pandemic disrupted individual and social behaviors and norms, including outdoor activities. A recreational angling survey of 18,000 licensed anglers from 10 states (AR, CT, FL, IA, MO, NC, SC, TX, UT, WY) was conducted in summer 2020 to characterize recreational fishing trends during the first few months of the pandemic. The study presented here builds off this survey by combining the survey data with county-level human population density and spring 2020 per capita COVID-19 cases to understand how anglers responded to the pandemic along the urban-to-rural continuum. Specifically, we wanted to know if population density or COVID-19 cases per capita influenced angler-reported 1) changes in license sales, 2) number of fishing trips, and 3) motivation for fishing. Overall results suggest that per capita COVID-19 cases were more influential in driving angler behavior than population density in the early pandemic (01 March 2020–31 May 2020). At the onset of the pandemic, high COVID-19 case counts were associated with an uptick in recreational angling activity. In counties with greater COVID-19 case counts, there was greater angler recruitment (i.e., attraction of new individuals to recreational fishing) and earlier license purchases. Anglers aged ≥40 years and earning ≥$50,000 living in areas of greater per capita COVID-19 cases also went on more fishing trips than they typically would. Angler motivations varied across gradients of population density and per capita COVID-19 cases: anglers living in areas of higher population densities were more likely to report fishing for stress relief, sport, and competition among friends , and anglers living in areas of higher per capita COVID-19 cases were more likely to report fishing for sport and because they had free time and less likely to report fishing for food . Management efforts can focus on retaining and reactivating pandemic anglers.

Fisheries Research↗
USGS2024

Adaptive capacities of inland fisheries facing anthropogenic pressures

Inland fisheries face multiple, intensifying threats (i.e., proximate human pressures causing degraded ecological attributes) from land development, climate change, resource extraction, and competing demands for water resources. Planning for resiliency amidst these pressures requires understanding the factors that influence an inland fishery’s capacity to adapt to system changes under multiple threats. Incorporating expert knowledge can illuminate priority fisheries and provide important insights where data are otherwise limited. Using data from a global survey of 536 fishery professionals, this study examines perceptions of threats and adaptive capacity (i.e., ability to mitigate or respond to change) in major inland fisheries. We assessed associations across 29 different perceived threats and their ranked influence scores, tested agreement among five adaptive capacity domains (i.e., agency, assets, flexibility, learning, organization), and examined relationships between threats and adaptive capacity domains. Results provide quantitative evidence that the greatest threats to inland fisheries come from outside the fishing sector and that most inland fisheries face multiple threats. Results also support the five domains as a collective measure of adaptive capacity and illuminate a negative association between the threats to a fishery and a fishery’s adaptive capacity. These findings highlight the need for fishery managers to engage in decision making with non-fishery sectors (e.g., multi-sectoral management) and the prioritization of habitat and watershed-scale conservation and rehabilitation efforts for improved adaptability amidst ecological transformation.

Global Environmental Change↗
USGS2024

Can the planetary health concept save freshwater biodiversity and ecosystems?

People clearly need and benefit from healthy freshwater ecosystems; Given the precarious state of these important systems and services, current efforts to address the freshwater biodiversity crisis remain insufficient. Planetary health is an emerging framework that aims to secure the state of natural systems within environmental limits that ensure humanity can flourish. The planetary health concept is tied to the planetary boundaries framework in which various ecological thresholds are identified with the goal of constraining human activity to within those boundaries (so-called safe operating spaces). Freshwater systems are influenced by some planetary-scale processes like the climate systems and phosphorus and nitrogen cycles. Nonetheless, safe boundaries to guide the conservation and management of freshwater ecosystems need to consider their uneven distribution around the globe, and their ecological and hydrologic limits, which are often site and context dependent. Efforts to down-scale planetary boundaries concepts to the management of freshwater recreational fisheries at the lake scale, suggest that there are opportunities for rethinking planetary health as a nested cross-scale approach from the planet to the watershed.

Lancet Planetary Health↗
USGS2023

Climate impacts to inland fishes: Shifting research topics over time

Climate change remains a primary threat to inland fishes and fisheries. Using topic modeling to examine trends and relationships across 36 years of scientific literature on documented and projected climate impacts to inland fish, we identify ten representative topics within this body of literature: assemblages, climate scenarios, distribution, climate drivers, population growth, invasive species, populations, phenology, physiology, and reproduction. These topics are largely similar to the output from artificial intelligence application (i.e., ChatGPT) search prompts, but with some key differences. The field of climate impacts on fish has seen dramatic growth since the mid-2000s with increasing popularity of topics related to drivers, assemblages, and phenology. The topics were generally well-dispersed with little overlap of common words, apart from phenology and reproduction which were closely clustered. Pairwise comparisons between topics revealed potential gaps in the literature including between reproduction and distribution and between physiology and phenology. A better understanding of these relationships can help capitalize on existing literature to inform conservation and sustainable management of inland fishes with a changing climate.

PLOS Climate↗
USGS2023

CreelCat, a Catalog of United States Inland Creel and Angler Survey Data

The United States Inland Creel and Angler Survey Catalog (CreelCat) contains a national compilation of angler and creel survey data collected by natural resource management agencies across the United States (including Washington, D.C. and Puerto Rico). These surveys are used to help inform the management of recreational fisheries, by collecting information about anglers including what they are catching and harvesting, the amount of effort they expend, their angling preferences, and demographic information. As of May 1, 2023, CreelCat houses over 14,729 surveys from 33 states, Puerto Rico, and Washington, D.C., comprising 235 data fields across 8 tables. These tables contain 235,015 records of fish catch and harvest metrics, 27,250 angler preference metrics, 14,729 records of survey characteristics, 13,576 records of effort metrics, and 409 records of angler demographics. Though individual creel surveys are often deployed to meet local science and management objectives, creel data aggregated across jurisdictions has the potential to address larger scale research and management needs.

Scientific Data↗
USGS2023

Reimagining large river management using the Resist–Accept–Direct (RAD) framework in the Upper Mississippi River

Background Large-river decision-makers are charged with maintaining diverse ecosystem services through unprecedented social-ecological transformations as climate change and other global stressors intensify. The interconnected, dendritic habitats of rivers, which often demarcate jurisdictional boundaries, generate complex management challenges. Here, we explore how the Resist–Accept–Direct (RAD) framework may enhance large-river management by promoting coordinated and deliberate responses to social-ecological trajectories of change. The RAD framework identifies the full decision space of potential management approaches, wherein managers may resist change to maintain historical conditions, accept change toward different conditions, or direct change to a specified future with novel conditions. In the Upper Mississippi River System, managers are facing social-ecological transformations from more frequent and extreme high-water events. We illustrate how RAD-informed basin-, reach-, and site-scale decisions could: (1) provide cross-spatial scale framing; (2) open the entire decision space of potential management approaches; and (3) enhance coordinated inter-jurisdictional management in response to the trajectory of the Upper Mississippi River hydrograph. Results The RAD framework helps identify plausible long-term trajectories in different reaches (or subbasins) of the river and how the associated social-ecological transformations could be managed by altering site-scale conditions. Strategic reach-scale objectives may reprioritize how, where, and when site conditions could be altered to contribute to the basin goal, given the basin’s plausible trajectories of change (e.g., by coordinating action across sites to alter habitat connectivity, diversity, and redundancy in the river mosaic). Conclusions When faced with long-term systemic transformations (e.g., > 50 years), the RAD framework helps explicitly consider whether or when the basin vision or goals may no longer be achievable, and direct options may open yet unconsidered potential for the basin. Embedding the RAD framework in hierarchical decision-making clarifies that the selection of actions in space and time should be derived from basin-wide goals and reach-scale objectives to ensure that site-scale actions contribute effectively to the larger river habitat mosaic. Embedding the RAD framework in large-river decisions can provide the necessary conduit to link flexibility and innovation at the site scale with stability at larger scales for adaptive governance of changing social-ecological systems.

Upper Mississippi River↗