Scholarly Works, Fish and Wildlife Conservation

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Research articles, presentations, and other scholarship

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Crayfishes of the New River watershed and Factors Affecting Their Distributions
Mouser, Joshua; Loughman, Zachary; Frimpong, Emmanuel A. (New River Symposium, 2024-04-12)
Crayfishes are keystone species within aquatic ecosystems and many species require conservation efforts to support their continued persistence. Unfortunately, we lack basic data needed to make effective conservation decisions for many crayfishes, especially those that occur in the New River watershed (hereafter New River). Therefore, we investigated coarse-scale drivers of crayfish occurrence in the New River. We used generalized linear mixed effects models to predict occurrence of eight taxa based on instream and landscape-scale environmental data and biotic interactions. There are at least 10 species of crayfishes that occur in the New River. Faxonius cristavarius, F. virilis, Cambarus appalachiensis, and C. chasmodactylus are found in larger tributaries throughout the New River. The following species occupy smaller tributaries of the New River: F. spp. (either F. sanbornii or F. obscurus), C. aff. robustus, C. cf. bartonii, and C. smilax. We found that increasing anthropogenic disturbance led to declines in F. spp., C. cf. bartonii, and C. smilax but had a positive relationship with F. cristavarius. The presence of the potentially invasive species, F. cristivarius, was negatively associated with most species. Embeddedness, substrate, proportion riffle habitat, and lithology were additional variables that structured crayfish assemblages. Our results reveal that increasing human-mediated changes and invasive crayfishes threaten the persistence of native crayfishes in the New River.
Local knowledge reconstructs historical resource use
Castello, Leandro; Martins, Eduardo G.; Sorice, Michael G.; Smith, Eric P.; Almedia, Morgana; Bastos, Gastao C.C.; Gardoso, Luis G.; Clauzet, Mariana; Dopona, Alisson P.; Ferreira, Beatrice; Haimovic, Manuel; Jorge, Marcelo; Mendonça, Jocemar; Ávila-da- Silva, Antonio O.; Roman, Ana P.O.; Ramires, Milena; de Miranda, Laura V.; Lopes, Priscila F.M. (Wiley, 2024-03-07)
Information on natural resource exploitation is vital for conservation but scarce in developing nations, which encompass most of the world and often lack the capacity to produce it. A growing approach to generate information about resource use in the context of developing nations relies on surveys of resource users about their recollections (recall) of past harvests. However, the reliability of harvest recalls remains unclear. Here, we show that harvest recalls can be as accurate to data collected by standardized protocols, despite that recalls are variable and affected by the age of the recollecting person and the length of time elapsed since the event. Samples of harvest recalls permit relatively reliable reconstruction of harvests for up to 39 years in the past. Harvest recalls therefore have strong potential to inform data-poor resource systems and curb shifting baselines around the world at a fraction of the cost of conventional approaches.
Niche partitioning and the storage effect facilitate coexistence in an amphibian community
Brooks, George C.; Caruso, Nicholas M.; Chandler, Houston C.; Haas, Carola A. (Wiley, 2023-10-18)
Virtually all natural community assemblages are dominated by a handful of common species. Dominant species can exert negative impacts on biodiversity through competitive exclusion, and thus there is a strong incentive to understand imbalances in community composition, changes in dominance hierarchies through time, and mechanisms of coexistence. Pond-breeding amphibians that utilize ephemeral wetlands provide an excellent opportunity to evaluate theoretical predictions of community composition in stochastic environments. One of the most striking features of pond-breeding amphibians is the marked stochastic fluctuations in abundance across years. Given strong theoretical and empirical links between evenness and biomass, one would expect community evenness to change from year to year. Moreover, if different species exhibit different boom-and-bust reproductive cycles, then a storage effect may help to explain why one species does not outcompete all others. Here, we explore the interplay between biotic and abiotic conditions in shaping amphibian communities at two ephemeral wetlands on Eglin Air Force Base, Florida. We document consistent community composition over 6 years of monitoring, resulting from a lack of species turnover and similar responses of all community members to environmental conditions. The similar dynamics of species argues against a storage effect as the sole mechanism for coexistence and instead points to niche partitioning as a more important factor. In support of this conclusion, we show that the degree of synchrony in breeding migrations only correlates with environmental conditions within species, not between species. The lack of pattern seen between species implies that individuals are somewhat constrained in the timing of breeding migrations, perhaps owing in part to competition with other community members. We hope that our work reinvigorates interest in amphibian communities and highlights ephemeral wetlands as model systems to study community dynamics in stochastic environments.
Forecasting the flooding dynamics of flatwoods salamander breeding wetlands under future climate change scenarios
Chandler, Houston C.; Caruso, Nicholas M.; McLaughlin, Daniel L.; Jiao, Yan; Brooks, George C.; Haas, Carola A. (PeerJ, 2023-09-19)
Ephemeral wetlands are globally important systems that are regulated by regular cycles of wetting and drying, which are primarily controlled by responses to relatively short-term weather events (e.g., precipitation and evapotranspiration). Climate change is predicted to have significant effects on many ephemeral wetland systems and the organisms that depend on them through altered filling or drying dates that impact hydroperiod. To examine the potential effects of climate change on pine flatwoods wetlands in the southeastern United States, we created statistical models describing wetland hydrologic regime using an approximately 8-year history of water level monitoring and a variety of climate data inputs. We then assessed how hydrology may change in the future by projecting models forward (2025–2100) under six future climate scenarios (three climate models each with two emission scenarios). We used the model results to assess future breeding conditions for the imperiled Reticulated Flatwoods Salamander (Ambystoma bishopi), which breeds in many of the study wetlands. We found that models generally fit the data well and had good predictability across both training and testing data. Across all models and climate scenarios, there was substantial variation in the predicted suitability for flatwoods salamander reproduction. However, wetlands with longer hydroperiods tended to have fewer model iterations that predicted at least five consecutive years of reproductive failure (an important metric for population persistence). Understanding potential future risk to flatwoods salamander populations can be used to guide conservation and management actions for this imperiled species.
Accessible birding in the United States: constraints to and facilitators of birding with disabilities
Sinkular, Emily N.; Dayer, Ashley A.; McGregor, Freya A.; Karns, Morgan J. (Taylor & Francis, 2024-03-26)
While approximately one-quarter of the U.S. population has a disability, many people with disabilities remain excluded from equitable participation in birding. In this study, we compared the constraints and facilitators of birders with and without disabilities from a nationwide survey of U.S. wildlife viewers. Next, we analyzed open-ended responses in a survey of birders with disabilities to characterize constraints and facilitators using models of disabilities, or different frames of reference to understand disabilities. We found that birders with disabilities, compared to those without, experienced constraints to birding to a greater extent. However, birders with and without disabilities expressed interest in various facilitators (e.g. access to more high-quality birding locations, information about birding), suggesting that facilitators can benefit both groups. Birders invoked multiple models when describing their constraints to and facilitators of birding, highlighting a need for a multi-faceted approach to fostering greater levels of inclusivity in birding.
Extending Body Condition Scoring Beyond Measureable Rump Fat to Estimate Full Range of Nutritional Condition for Moose
Levine, Rebecca; Smiley, Rachel; Jesmer, Brett R.; Oates, Brendan; Goheen, Jacob; Stephenson, Gary; Kauffman, Matthew; Fralick, Gary; Monteith, Kevin (2023-02-18)
Moose (Alces alces) populations along the southern extent of their range are largely declining, and there is growing evidence that nutritional condition — which influences several vital rates – is a contributing factor. Moose body condition can presently be estimated only when there is measurable subcutaneous rump fat, which equates to animals with >6% ingesta-free body fat (IFBFat). There is need for a technique to allow body fat estimation of animals in poorer body condition (i.e., <6% body fat). We advance current methods for moose, following those used and validated with other ungulate species, by establishing a moose-specific body condition score (BCS) that can be used to estimate IFBFat in the lower range of condition. Our modified BCS was related strongly (r2 = 0.89) to IFBFat estimates based on measurable rump fat. By extending the predicted relationship to individuals without measurable fat, the BCS equated severe emaciation with 0.67% IFBFat, supporting the accuracy of the method. The lower end of nutritional condition is important for identifying relationships involving life-history characteristics because most state-dependent changes occur at lower levels of condition. Therefore, until the BCS can be validated with moose carcasses, we believe our method to estimate body fat across the full range of condition should yield better understanding of the drivers underlying declining moose populations.
Biological Earth observation with animal sensors
Jetz, Walter; Tertitski, Grigori; Kays, Roland; Mueller, Uschi; Wikelski, Martin; Akesson, Susanne; Anisimov, Yury; Antonov, Aleksey; Arnold, Walter; Bairlein, Franz; Balta, Oriol; Baum, Diane; Beck, Mario; Belonovich, Olga; Belyaev, Mikhail; Berger, Matthias; Berthold, Peter; Bittner, Steffen; Blake, Stephen; Block, Barbara; Bloche, Daniel; Boehning-Gaese, Katrin; Bohrer, Gil; Bojarinova, Julia; Bommas, Gerhard; Bourski, Oleg; Bragin, Albert; Bragin, Alexandr; Bristol, Rachel; Brlik, Vojtech; Bulyuk, Victor; Cagnacci, Francesca; Carlson, Ben; Chapple, Taylor K.; Chefira, Kalkidan F.; Cheng, Yachang; Chernetsov, Nikita; Cierlik, Grzegorz; Christiansen, Simon S.; Clarabuch, Oriol; Cochran, William; Cornelius, Jamie Margaret; Couzin, Iain; Crofoot, Margret C.; Cruz, Sebastian; Davydov, Alexander; Davidson, Sarah; Dech, Stefan; Dechmann, Dina; Demidova, Ekaterina; Dettmann, Jan; Dittmar, Sven; Dorofeev, Dmitry; Drenckhahn, Detlev; Dubyanskiy, Vladimir; Egorov, Nikolay; Ehnbom, Sophie; Ellis-Soto, Diego; Ewald, Ralf; Feare, Chris; Fefelov, Igor; Fehervari, Peter; Fiedler, Wolfgang; Flack, Andrea; Froboese, Magnus; Fufachev, Ivan; Futoran, Pavel; Gabyshev, Vyachaslav; Gagliardo, Anna; Garthe, Stefan; Gashkov, Sergey; Gibson, Luke; Goymann, Wolfgang; Gruppe, Gerd; Guglielmo, Chris; Hartl, Phil; Hedenstrom, Anders; Hegemann, Arne; Heine, Georg; Ruiz, Maggi Hieber; Hofer, Heribert; Huber, Felix; Hurme, Edward; Iannarilli, Fabiola; Illa, Marc; Isaev, Arkadiy; Jakobsen, Bent; Jenni, Lukas; Jenni-Eiermann, Susi; Jesmer, Brett R.; Jiguet, Frederic; Karimova, Tatiana; Kasdin, N. Jeremy; Kazansky, Fedor; Kirillin, Ruslan; Klinner, Thomas; Knopp, Andreas; Koelzsch, Andrea; Kondratyev, Alexander; Krondorf, Marco; Ktitorov, Pavel; Kulikova, Olga; Kumar, R. Suresh; Kuenzer, Claudia; Larionov, Anatoliy; Larose, Christine; Liechti, Felix; Linek, Nils; Lohr, Ashley; Lushchekina, Anna; Mansfield, Kate; Matantseva, Maria; Markovets, Mikhail; Marra, Peter; Masello, Juan F.; Melzheimer, Joerg; Menz, Myles HM M.; Menzie, Stephen; Meshcheryagina, Swetlana; Miquelle, Dale; Morozov, Vladimir; Mukhin, Andrey; Mueller, Inge; Mueller, Thomas; Navedo, Juan G.; Nathan, Ran; Nelson, Luke; Nemeth, Zoltan; Newman, Scott; Norris, Ryan; Nsengimana, Olivier; Okhlopkov, Innokentiy; Oles, Wioleta; Oliver, Ruth; O'Mara, Teague; Palatitz, Peter; Partecke, Jesko; Pavlick, Ryan; Pedenko, Anastasia; Perry, Alys; Pham, Julie; Piechowski, Daniel; Pierce, Allison; Piersma, Theunis; Pitz, Wolfgang; Plettemeier, Dirk; Pokrovskaya, Irina; Pokrovskaya, Liya; Pokrovsky, Ivan; Pot, Morrison; Prochazka, Petr; Quillfeldt, Petra; Rakhimberdiev, Eldar; Ramenofsky, Marilyn; Ranipeta, Ajay; Rapczynski, Jan; Remisiewicz, Magdalena; Rozhnov, Viatcheslav; Rienks, Froukje; Rozhnov, Vyacheslav; Rutz, Christian; Sakhvon, Vital; Sapir, Nir; Safi, Kamran; Schaeuffelhut, Friedrich; Schimel, David; Schmidt, Andreas; Shamoun-Baranes, Judy; Sharikov, Alexander; Shearer, Laura; Shemyakin, Evgeny; Sherub, Sherub; Shipley, Ryan; Sica, Yanina; Smith, Thomas B.; Simonov, Sergey; Snell, Katherine; Sokolov, Aleksandr; Sokolov, Vasiliy; Solomina, Olga; Spina, Fernando; Spoelstra, Kamiel; Storhas, Martin; Sviridova, Tatiana; Swenson, George; Taylor, Phil; Thorup, Kasper; Tsvey, Arseny; Tucker, Marlee; Tuppen, Sophie; Turner, Woody; Twizeyimana, Innocent; van der Jeugd, Henk; van Schalkwyk, Louis; van Toor, Marielle; Viljoen, Pauli; Visser, Marcel E.; Volkmer, Tamara; Volkov, Andrey; Volkov, Sergey; Volkov, Oleg; von Ronn, Jan AC C.; Vorneweg, Bernd; Wachter, Bettina; Waldenstrom, Jonas; Weber, Natalie; Wegmann, Martin; Wehr, Aloysius; Weinzierl, Rolf; Weppler, Johannes; Wilcove, David; Wild, Timm; Williams, Hannah J.; Wilshire, John H.; Wingfield, John; Wunder, Michael; Yachmennikova, Anna; Yanco, Scott; Yohannes, Elisabeth; Zeller, Amelie; Ziegler, Christian; Ziecik, Anna; Zook, Cheryl (Cell Press, 2022-05-22)
Space-based tracking technology using low-cost miniature tags is now delivering data on fine-scale animal movement at near-global scale. Linked with remotely sensed environmental data, this offers a biological lens on habitat integrity and connectivity for conservation and human health; a global network of animal sentinels of environmental change.
Characterization of Diarrheagenic Escherichia coli Isolated from Food, Food Waste, and Water from the Chobe Region of Botswana
Bywater, Auja L.; Ponder, Monica A.; Alexander, Kathleen A. (2023-04-21)
Antibiotic Susceptibility of non-pathogenic Escherichia coli from meat and produce available in the Chobe region of Botswana
Saunders, Rachel; Bywater, Auja L.; Fleming, Madison; Kelly, Christine; Nuckolls, Evan; Alexander, Kathleen A.; Ponder, Monica A. (2023-04-21)
Enabling regulatory policy globally will promote realization of the potential of animal biotechnology
Hallerman, Eric M.; Bredlau, Justin; Camargo, Luiz S. A.; Dagli, Maria L. Z.; Karembu, Margaret; Kovich, Daniel; Muia, Anne N.; Murrone, Mariana L.; Rocha-Salavarrieta, Pedro J.; Romero-Aldemita, Rhodora; Tizard, Mark; Walton, Mark; Wray-Cahen, Diane (2024-03-06)
Animal biotechnologies have the potential to improve the sustainability and security of our global food systems. Government regulatory authorities are responsible for ensuring the safety of food their citizens consume, whether it is produced via conventional breeding methods or biotechnologies. While some countries have implemented animal biotechnology oversight policies, many countries have yet to develop theirs. Historically, regulatory approvals were required before products of biotechnology could enter the marketplace, and the high cost of the approval process limited the number and types of animal and plant products that sought approval. Only one biotech animal in the world that was developed for food production has reached the market under a GMO or rDNA approval process. The advent of genome editing techniques has revolutionized the scientific approach to introducing changes into DNA sequences and how biotechnology can be used to enhance agricultural breeding. Regulatory dialogs about biotechnology also have changed as a result of these new technologies. Regulatory agencies have begun to respond to these scientific advances, and a growing number of countries are looking to modernize regulatory approaches for these products, based on risk (or lack thereof) and similarity to organisms that could be produced via conventional breeding methods. Advances in animal biotechnology, especially genome editing, can accelerate the incorporation of valued phenotypes in animals, including enhanced yield, disease resistance, resilience to changing climate, and improved animal welfare, as well as food qualities valued by consumers. For animals with these biotechnology-introduced traits to enter agricultural production and reach consumers, clear risk-proportionate regulatory approaches must be in place, and to facilitate international trade of animal products, regulatory processes need to be aligned and compatible. Effective scientific public communication is crucial to build public trust in precision animal biotechnology and risk-proportionate regulatory approaches. An international workshop on regulatory approaches for animal biotechnology was convened in 2022 with 27 countries represented. We synthesize here technical progress, development of regulatory policy, and strategies for engagement with diverse publics on animal biotechnology reported in the workshop. Our goal is to encourage development and implementation of risk-proportionate regulatory approaches and policies in a global context.
Population Genetic Differentiation of Walleye (Sander vitreus) across the Eastern Highlands of the United States
Harris, Sheila C.; Palmer, George; Stepien, Carol A.; Hallerman, Eric M. (MDPI, 2023-12-29)
Walleye is an important sportfish across eastern North America, is commercially fished in the Laurentian Great Lakes region, and has been introduced outside its native range. Thirty-eight Walleye populations within six watersheds across the Eastern Highlands and other portions of the native range were screened at eight microsatellite DNA loci to better understand evolutionary history and to inform fishery management and conservation efforts. Population genetic variation showed divergent assemblages of populations, respectively, living in the Mobile Bay, Mississippi River, Eastern Highlands (Tennessee, New, and Ohio Rivers), and Great Lakes drainages today. All estimates of effective numbers of breeding individuals were under 25, and all populations within all watersheds had ~15–20% inter-individual relatedness, likely attributable to the effects of both natural demographic processes and stocking. The extent of Eastern Highlands Walleye includes both the Ohio and Tennessee River basins.
Shark detection and classification with machine learning
Jenrette, Jeremy; Liu, Zac; Chimote, Pranav; Hastie, Trevor; Fox, Edward; Ferretti, Francesco (Elsevier, 2022-07-01)
Influences of Satellite Sensor and Scale on Derivation of Ecosystem Functional Types and Diversity
Liu, Lingling; Smith, Jeffrey R.; Armstrong, Amanda H.; Alcaraz-Segura, Domingo; Epstein, Howard E.; Echeverri, Alejandra; Langhans, Kelley E.; Schmitt, Rafael J. P.; Chaplin-Kramer, Rebecca (MDPI, 2023-12-01)
Satellite-derived Ecosystem Functional Types (EFTs) are increasingly used in ecology and conservation to characterize ecosystem heterogeneity. The diversity of EFTs, also known as Ecosystem Functional Diversity (EFD), has been suggested both as a potential metric of ecosystem-level biodiversity and as a predictor for ecosystem functioning, ecosystem services, and resilience. However, the impact of key methodological choices on patterns of EFTs and EFD have not been formally assessed. Using Costa Rica as a study system, we compared EFTs and EFD, derived from MODIS and Landsat data using different methodological assumptions, at both national and local extents. Our results showed that the regional spatial patterns of EFTs and EFD derived from 250 m MODIS and 30 m Landsat are notably different. The selection of sensors for deriving EFTs and EFD is dependent on the study area, data quality, and the research objective. Given its finer spatial resolution, Landsat has greater capacity to differentiate more EFTs than MODIS, though MODIS could be a better choice in frequently cloudy areas due to its shorter revisiting time. We also found that the selection of spatial extent used to derive EFD is critical, as smaller extents (e.g., at a local rather than a national scale) can show much higher diversity. However, diversity levels derived at smaller extents appear to be nested within the diversity levels derived at larger extents. As EFTs and EFD continue to develop as a tool for ecosystem ecology, we highlight the important methodological choices to ensure that these metrics best fit research objectives.
Birds are not the only ones impacted by guidance to cease bird feeding
Dayer, Ashley A.; Pototsky, P. Christy; Hall, Richard J.; Hawley, Dana M.; Phillips, Tina B.; Bonter, David N.; Dietsch, Allan M.; Greig, Emma; Hochachka, Wesley M. (Wiley, 2023)
1. Humans have a particularly strong connection with birds, driving the enormous popularity of residential bird feeding in much of the world. 2. We conducted a web search to document US state wildlife management agency responses to two recent avian disease outbreaks, finding that 23 agencies made recommendations to cease feeding wild birds in 2021–2022. 3. The psychological benefits of bird feeding for humans are well-documented but often overlooked in management decisions in response to avian disease outbreaks. 4. Likewise, ecological evidence does not necessarily support ceasing bird feeding to reduce the spread of every avian disease. 5. Ecological and social science need to be applied in tandem to ensure that well-intended guidance to cease feeding of birds does not have unintended consequences.
Climate change linked to vampire bat expansion and rabies virus spillover
Van de Vuurst, Paige; Qiao, Huijie; Soler-Tovar, Diego; Escobar, Luis E. (Wiley, 2023-10)
Bat-borne pathogens are a threat to global health and in recent history have had major impacts on human morbidity and mortality. Examples include diseases such as rabies, Nipah virus encephalitis, and severe acute respiratory syndrome (SARS). Climate change may exacerbate the emergence of bat-borne pathogens by affecting the ecology of bats in tropical ecosystems. Here, we report the impacts of climate change on the distributional ecology of the common vampire bat Desmodus rotundus across the last century. Our retrospective analysis revealed a positive relationship between changes in climate and the northern expansion of the distribution of D. rotundus in North America. Furthermore, we also found a reduction in the standard deviation of temperatures at D. rotundus capture locations during the last century, expressed as more consistent, less-seasonal climate in recent years. These results elucidate an association between D. rotundus range expansion and a continental-level rise in rabies virus spillover transmission from D. rotundus to cattle in the last 50 years of the 120-year study period. This correlative study, based on field observations, offers empirical evidence supporting previous statistical and mathematical simulation-based studies reporting a likely increase of bat-borne diseases in response to climate change. We conclude that the D. rotundus rabies system exemplifies the consequences of climate change augmentation at the wildlife–livestock–human interface, demonstrating how global change acts upon these complex and interconnected systems to drive increased disease emergence.
Genetic Structure across Isolated Virginia Populations of the Endangered Candy Darter (Etheostoma osburni)
McBaine, Kathryn E.; Angermeier, Paul L.; Hallerman, Eric M. (MDPI, 2023-10-01)
Candy darter Etheostoma osburni, a federally endangered non-game fish, has been extirpated from most of its historic range in Virginia and now occurs in four isolated populations in the New River drainage. Understanding of population genetic structure will provide insights into the recent natural history of the species and can inform conservation management. Our objectives were to: characterize population genetic structure, estimate and compare effective population sizes (N_e), and use this information to infer recent population history. Variation at mitochondrial cytochrome b sequences among 150 individuals showed 10 haplotypes separated by 1–14 mutational steps, some shared and some unique to particular populations. Variation at 12 microsatellite loci among 171 individuals showed lower variation in Dismal Creek than in other populations. All populations showed evidence of having experienced a genetic bottleneck and were highly differentiated from one another based on both types of DNA markers. Population genetic structure was related to stream position in regard to the New River, suggesting that populations were once connected. N_e estimates for all populations were less than the 500 recommended to maintain evolutionary potential, but most estimates were greater than the 100 needed for use as source populations. Our findings indicate that habitat management to allow expansion of populations, and translocations to exchange genetic material among populations, may be effective tactics to promote conservation of candy darter in Virginia.
Campylobacter in aquatic and terrestrial mammals is driven by life traits: A systematic review and meta-analysis
Brooks, Michael R.; Medley, Sarah; Ponder, Monica A.; Alexander, Kathleen A. (Frontiers, 2023-02)
Introduction: Campylobacter spp. infections are responsible for significant diarrheal disease burden across the globe, with prevalence thought to be increasing. Although wild avian species have been studied as reservoirs of Campylobacter spp., our understanding of the role of wild mammalian species in disease transmission and persistence is limited. Host factors influencing infection dynamics in wild mammals have been neglected, particularly life traits, and the role of these factors in zoonotic spillover risk is largely unknown. Methods: Here, we conducted a systematic literature review, identifying mammalian species that had been tested for Campylobacter spp. infections (molecular and culture based). We used logistic regression to evaluate the relationship between the detection of Campylobacter spp. in feces and host life traits (urban association, trophic level, and sociality). Results: Our analysis suggest that C. jejuni transmission is associated with urban living and trophic level. The probability of carriage was highest in urban-associated species (p = 0.02793) and the most informative model included trophic level. In contrast, C. coli carriage appears to be strongly influenced by sociality (p = 0.0113) with trophic level still being important. Detection of Campylobacter organisms at the genus level, however, was only associated with trophic level (p = 0.0156), highlighting the importance of this trait in exposure dynamics across host and Campylobacter pathogen systems. Discussion: While many challenges remain in the detection and characterization of Camploybacter spp., these results suggest that host life traits may have important influence on pathogen exposure and transmission dynamics, providing a useful starting point for more directed surveillance approaches.
Coursing hyenas and stalking lions: The potential for inter- and intraspecific interactions
Barker, Nancy A.; Joubert, Francois G.; Kasaona, Marthin; Shatumbu, Gabriel A.; Stowbunenko, Vincent; Alexander, Kathleen A.; Slotow, Rob; Getz, Wayne M. (Public Library of Science, 2023-02)
Resource partitioning promotes coexistence among guild members, and carnivores reduce interference competition through behavioral mechanisms that promote spatio-temporal separation. We analyzed sympatric lion and spotted hyena movements and activity patterns to ascertain the mechanisms facilitating their coexistence within semi-arid and wetland ecosystems. We identified recurrent high-use (revisitation) and extended stay (duration) areas within home ranges, as well as correlated movement-derived measures of inter- and intraspecific interactions with environmental variables. Spatial overlaps among lions and hyenas expanded during the wet season, and occurred at edges of home ranges, around water-points, along pathways between patches of high-use areas. Lions shared more of their home ranges with spotted hyenas in arid ecosystems, but shared more of their ranges with conspecifics in mesic environments. Despite shared space use, we found evidence for subtle temporal differences in the nocturnal movement and activity patterns between the two predators, suggesting a fine localized-scale avoidance strategy. Revisitation frequency and duration within home ranges were influenced by interspecific interactions, after land cover categories and diel cycles. Intraspecific interactions were also important for lions and, important for hyenas were moon illumination and ungulates attracted to former anthrax carcass sites in Etosha, with distance to water in Chobe/Linyanti. Recursion and duration according to locales of competitor probabilities were similar among female lions and both sexes of hyenas, but different for male lions. Our results suggest that lions and spotted hyenas mediate the potential for interference competition through subtle differences in temporal activity, fine-scale habitat use differentiation, and localized reactive-avoidance behaviors. These findings enhance our understanding of the potential effects of interspecific interactions among large carnivore space-use patterns within an apex predator system and show adaptability across heterogeneous and homogeneous environments. Future conservation plans should emphasize the importance of inter- and intraspecific competition within large carnivore communities, particularly moderating such effects within increasingly fragmented landscapes.
An approach to assess data-less small-scale fisheries: examples from Congo rivers
Castello, Leandro; Carvalho, Felipe; Ateba, Nelly Ornelle Onana; Busanga, Alidor Kankonda; Ickowitz, Amy; Frimpong, Emmanuel A. (Springer, 2023-03)
Small-scale fisheries (SSF) account for much of the global fish catch, but data to assess them often do not exist, impeding assessments of their historical dynamics and status. Here, we propose an approach to assess 'data-less' SSF using local knowledge to produce data, life history theory to describe their historical multispecies dynamics, and length-based reference points to evaluate stock status. We demonstrate use of this approach in three data-less SSFs of the Congo Basin. Fishers' recalls of past fishing events indicated fish catch declined by 65-80% over the last half-century. Declines in and depletion of many historically important species reduced the diversity of exploited species, making the species composition of the catch more homogenous in recent years. Length-at-catch of 11 of the 12 most important species were below their respective lengths-at-maturity and optimal lengths (obtained from Fishbase) in recent years, indicating overfishing. The most overfished species were large-bodied and found in the Congo mainstem. These results show the approach can suitably assess data-less SSF. Fishers' knowledge produced data at a fraction of the cost and effort of collecting fisheries landings data. Historical and current data on fish catch, length-at-catch, and species diversity can inform management and restoration efforts to curb shifting baselines of these fisheries. Classification of stock status allows prioritizing management efforts. The approach is easy to apply and generates intuitive results, having potential to complement the toolkits of researchers and managers working in SSF and engage stakeholders in decision-making processes.
Comparing estimates of census and effective population size in an endangered amphibian
Brooks, George C.; Wendt, A.; Haas, Carola A.; Roberts, J. H. (Wiley, 2023-03)
The field of conservation has seen a shift in focus from monitoring trends in census population size to trends in `effective' population size. Numerous genetic methods exist for estimating effective population size, resulting in uncertainty among conservation practitioners as to which methods are most appropriate when conducting population assessments or evaluating recovery efforts. Demographic approaches offer a promising avenue to provide a link between census and effective population size using life-history information, but rarely do studies have all three sources of data (genetic, demographic, life history) necessary to perform an explicit evaluation of their performance. Using data from a long-term study of reticulated flatwoods salamanders (Ambystoma bishopi) in western Florida, USA, we assessed the magnitude of temporal variation in census population sizes oNTHORN and the effective number of breeders Nbo THORN of two breeding populations to (1) document changes in the number of breeding adults over the 9-year study duration, (2) determine whether N and Nb provide similar information about population size and trends and (3) compare alternative demographic and genetic approaches for estimating Nb. We found that genetic estimates of bN b, particularly if averaged across multiple estimation methods, closely tracked spatiotemporal variation in N. Demographic estimates of Nb also closely tracked N but were sensitive to the assumed variance in reproductive success. In the absence of genetic information, detailed knowledge of mating systems and the environmental factors that skew reproductive contributions appear necessary for demographic Nb to reliably inform management decisions. In these populations, bN b appears too small (<40 individuals) to confer long-term genetic resilience, highlighting the importance of restoring landscape connectivity and indicating that caution must be taken when sourcing animals for reintroduction efforts. More generally, our study reveals insights into the utility of alternative Nb estimation methods in guiding recovery efforts of threatened and endangered species.

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