Geology topics

Hannah Mann Thompson

Publications and source records attributed to Hannah Mann Thompson.

5 recordsLinked to original sources

USGS2025

Evaluation of the acute toxicity of the piscicide TFM to Burbot

Non-target animal sensitivity remains a concern when treating Laurentian Great Lakes streams with 4-nitro-3-(trifluoromethyl)phenol (TFM), the main pesticide used to control Sea Lamprey Petromyzon marinus as part of the bi-national Great Lakes Fishery Commission's Sea Lamprey Control Program. Populations of Burbot Lota lota , a historically and culturally important fish, inhabit some of the streams that are treated with TFM. While many species of fish inhabiting the Great Lakes streams have been assessed for sensitivity to TFM, we are not aware of previous research to assess the risk to Burbot. We assessed the sensitivity of Burbot to TFM using replicate 12-hour flow-through diluter toxicity tests. We found Burbot to have a median lethal concentration (LC 50 ) of 9.74 mg/L, while the minimum lethal concentration (LC 99.9 ) for Sea Lamprey was predicted to be 2.5 mg/L in similar waters. The resulting toxicity ratio (LC 50 of non-target organism/LC 99.9 of Sea Lamprey) of Burbot was 3.90, well above the toxicity ratios for known sensitive species. Our results suggest Burbot are not expected to be adversely affected during a typical TFM stream treatment.

Great Lakes↗

USGS2024

Applying local and global sensitivity analysis to inform bigheaded carp management

Natural resource managers commonly use population-level models to aid in understanding the status of target populations or the potential implications of management actions. Sensitivity analyses, specifically, local sensitivity analysis (LSA) and global sensitivity analysis (GSA), exist as tools to improve understanding of these models, the importance of specific parameters to model outcomes, and the assumptions inherent to population models. However, applied ecology and closely related fields such as fisheries and wildlife management rarely use LSA or GSA. Here, we apply LSA and GSA to the Spatially Explicit Invasive Carp Population model, a population-level model used to simulate and compare management actions on the invasive silver carp Hypophthalmichthys molitrix population in the Illinois River. The spatial structure within the model arises from the navigation “pools” that exist between navigation lock-and-dam in the river and are also the focus of fisheries management in the river. We completed LSA and GSA for two reasons: (1) to compare the importance of model input parameters on simulated model populations and (2) to demonstrate the use of LSA and GSA for population-level models. In our system, the most important sensitivity values generally were detected in Alton Pool. This pool is the farthest downstream and includes a direct connection with the Mississippi River. These results indicate that the population dynamics in Alton Pool are an important driver of the population dynamics throughout the Illinois River. Management outcomes in this system will, therefore, be strongly dependent on the dynamics of Alton Pool.

Illinois↗

USGS2023

Assessing the suitability of YY males and ZZ females as an invasive species population control method across life histories

Natural resource managers use tools to control invasive species. In theory, stocking YY males or ZZ females would allow managers to skew sex ratios until populations collapse. In combination with other suppression methods, such as removal, this approach could be incorporated into Integrated Pest Management plans. For example, fishery managers have stocked YY males to control isolated non-native brook trout ( Salvelinus fontinalis ) populations. However, life histories and demographic factors (e.g., lifespans) vary across species and could affect the feasibility of skewing sex ratios as an effective control strategy for a given population. Likewise, some species may have sex determinations that do not allow population control through sex-skewing methods. We compared five representative aquatic invasive species with global invasion ranges for potential control by skewing the sex ratio through closed population simulations: red swamp crayfish (Procambarus clarkii ), zebra mussels ( Dreissena polymorpha ), lake trout ( Salvelinus namaycush) , silver carp ( Hypophthalmichthys molitrix ), and Nile tilapia ( Oreochromis niloticus ). We determined that Nile tilapia, red swamp crayfish, and zebra mussels would be the most suitable to control through skewing the sex ratio assuming appropriate sex determination exists in the species. Lake trout could be eliminated by stocking YY males but would require either long stocking periods or high stocking numbers because of the long lifespan of the species. Silver carp populations were more difficult to crash because they live longer and produce many recruits. Broadly, these patterns demonstrated that short lived species lend themselves to control by skewing the sex ratio.

Biological Invasions↗

USGS2023

MetaIPM: Placing integral projection models into a metapopulation framework

Metapopulation models include spatial population dynamics such as dispersion and migration between subpopulations. Integral projection models (IPMs) can include demographic rates as a function of size. Traditionally, metapopulation models do not included detailed populaiton models such as IPMs. In some situations, both local population dynamics (e.g. size-based survival) and spatial dynamics are important. We present a Python package, MetaIPM , which places IPMs into a metapopulation framework, and allow users to readily construct and apply these models that combine local population dynamics within a metapopulation framework. MetaIPM includes an IPM for each subpopulation that is connected to other subpopulations via a metapopulation movement model. These movements can include dispersion, migration or other patterns. The IPM can include for size-specific demographic rates (e.g. survival, recruitment) as well as management actions, such as length-based harvest (e.g. gear specific capture sizes, varying slot limits across political boundaries). The model also allows for changes in metapopulation connectivity between locations, such as a fish passage ladders to enhance movement or deterrents to reduce movement. Thus, resource managers can use MetaIPM to compare different management actions such as the harvest gear type (which can be length-specific) and harvest locations. We demonstrate how MetaIPM may be applied to inform managers seeking to limit the spread of an invasive species in a system with important metapopulation dynamics. Specifically, we compared removal lengths (all length fish versus longer fish only) for an invasive fish population in a fragmented, inland river system. MetaIPM allowed users to compare the importance of harvesting source populations away from the invasion front, as well as species at the invasion front. The model would also allow for future comparisons of different deterrent placement locations in the system. Moving beyond our example system, we describe how MetaIPM can be applied to other species, systems and management approaches. The MetaIPM packages includes Jupyter Notebooks documenting the package as well as a second set of JupyterNotebooks showing the application of the package to our example system.

Methods in Ecology and Evolution↗

USGS2023

Using a coupled integral projection model to investigate interspecific competition during an invasion: An application to silver carp (Hypophthalmichthys molitrix) and gizzard shad (Dorosoma cepedianum)

As a generalization of stage-based matrix models, integral projection models (IPMs) have been used to describe the size-based dynamics of wildlife and fisheries populations. Although some matrix models have explicitly included species interactions, few IPMs have expanded beyond single species, which limits their ability to describe the competitive dynamics of co-occuring taxa. We present a coupled system of IPMs where intra- and inter-specific competition may reciprocally affect the life-histories of two species. We investigated the potential role that competition has on two overlapping fish species in the upper Mississippi River system: the native gizzard shad ( Dorosoma cepedianum ) and the invasive silver carp ( Hypophthalmichthys molitrix ). Numerical simulations of this system indicated that the coupled IPMs could exhibit asymptotic behaviors similar to traditional, non-linear competition models. Specifically, by altering the competition coefficients, we demonstrate this model's ability to detect competitive exclusion, species coexistence, and dual extinction outcomes.

Letters in Biomathematics↗