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1. Tight spatial coupling of a marine predator with soniferous fishes: Using joint modelling to aid in ecosystem approaches to management

   https://doi.org/10.1111/ddi.13746  

   Roberts, Sarah M.; Jacoby, Ann‐Marie; Roberts, Jason J.; Leslie, Jaelyn; Payne, Khadijah L.; Read, Andrew J.; Halpin, Patrick N.; Barco, Susan; Garrison, Lance; McLellan, William; et al (August 2023, Diversity and Distributions)

   Enrico Pirotta (Ed.)

   Abstract AimUnderstanding the distribution of marine organisms is essential for effective management of highly mobile marine predators that face a variety of anthropogenic threats. Recent work has largely focused on modelling the distribution and abundance of marine mammals in relation to a suite of environmental variables. However, biotic interactions can largely drive distributions of these predators. We aim to identify how biotic and abiotic variables influence the distribution and abundance of a particular marine predator, the bottlenose dolphin (Tursiops truncatus), using multiple modelling approaches and conducting an extensive literature review. LocationWestern North Atlantic continental shelf. MethodsWe combined widespread marine mammal and fish and invertebrate surveys in an ensemble modelling approach to assess the relative importance and capacity of the environment and other marine species to predict the distribution of both coastal and offshore bottlenose dolphin ecotypes. We corroborate the modelled results with a systematic literature review on the prey of dolphins throughout the region to help explain patterns driven by prey availability, as well as reveal new ones that may not necessarily be a predator–prey relationship. ResultsWe find that coastal bottlenose dolphin distributions are associated with one family of fishes, the Sciaenidae, or drum family, and predictions slightly improve when using only fish versus only environmental variables. The literature review suggests that this tight coupling is likely a predator–prey relationship. Comparatively, offshore dolphin distributions are more strongly related to environmental variables, and predictions are better for environmental‐only models. As revealed by the literature review, this may be due to a mismatch between the animals caught in the fish and invertebrate surveys and the predominant prey of offshore dolphins, notably squid. Main ConclusionsIncorporating prey species into distribution models, especially for coastal bottlenose dolphins, can help inform ecological relationships and predict marine predator distributions. 

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2. Incorporating local adaptation into forecasts of species’ distribution and abundance under climate change

   https://doi.org/10.1111/gcb.14562  

   DeMarche, Megan L.; Doak, Daniel F.; Morris, William F. (January 2019, Global Change Biology)

   Abstract Populations of many species are genetically adapted to local historical climate conditions. Yet most forecasts of species’ distributions under climate change have ignored local adaptation (LA), which may paint a false picture of how species will respond across their geographic ranges. We review recent studies that have incorporated intraspecific variation, a potential proxy for LA, into distribution forecasts, assess their strengths and weaknesses, and make recommendations for how to improve forecasts in the face of LA. The three methods used so far (species distribution models, response functions, and mechanistic models) reflect a trade‐off between data availability and the ability to rigorously demonstrate LA to climate. We identify key considerations for incorporating LA into distribution forecasts that are currently missing from many published studies, including testing the spatial scale and pattern of LA, the confounding effects of LA to nonclimatic or biotic drivers, and the need to incorporate empirically based dispersal or gene flow processes. We suggest approaches to better evaluate these aspects of LA and their effects on species‐level forecasts. In particular, we highlight demographic and dynamic evolutionary models as promising approaches to better integrate LA into forecasts, and emphasize the importance of independent model validation. Finally, we urge closer examination of how LA will alter the responses of central vs. marginal populations to allow stronger generalizations about changes in distribution and abundance in the face of LA. 

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3. Guidelines for the use of spatially varying coefficients in species distribution models

   https://doi.org/10.1111/geb.13814  

   Doser, Jeffrey W.; Kéry, Marc; Saunders, Sarah P.; Finley, Andrew O.; Bateman, Brooke L.; Grand, Joanna; Reault, Shannon; Weed, Aaron S.; Zipkin, Elise F. (February 2024, Global Ecology and Biogeography)

   Abstract AimSpecies distribution models (SDMs) are increasingly applied across macroscales using detection‐nondetection data. These models typically assume that a single set of regression coefficients can adequately describe species–environment relationships and/or population trends. However, such relationships often show nonlinear and/or spatially varying patterns that arise from complex interactions with abiotic and biotic processes that operate at different scales. Spatially varying coefficient (SVC) models can readily account for variability in the effects of environmental covariates. Yet, their use in ecology is relatively scarce due to gaps in understanding the inferential benefits that SVC models can provide compared to simpler frameworks. InnovationHere we demonstrate the inferential benefits of SVC SDMs, with a particular focus on how this approach can be used to generate and test ecological hypotheses regarding the drivers of spatial variability in population trends and species–environment relationships. We illustrate the inferential benefits of SVC SDMs with simulations and two case studies: one that assesses spatially varying trends of 51 forest bird species in the eastern United States over two decades and a second that evaluates spatial variability in the effects of five decades of land cover change on grasshopper sparrow (Ammodramus savannarum) occurrence across the continental United States. Main conclusionsWe found strong support for SVC SDMs compared to simpler alternatives in both empirical case studies. Factors operating at fine spatial scales, accounted for by the SVCs, were the primary divers of spatial variability in forest bird occurrence trends. Additionally, SVCs revealed complex species–habitat relationships with grassland and cropland area for grasshopper sparrow, providing nuanced insights into how future land use change may shape its distribution. These applications display the utility of SVC SDMs to help reveal the environmental factors that drive species distributions across both local and broad scales. We conclude by discussing the potential applications of SVC SDMs in ecology and conservation. 

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4. Regional species gains outpace losses across North American continental shelf regions

   https://doi.org/10.1111/geb.13681  

   Kitchel, Zoë J.; Pinsky, Malin L. (April 2023, Global Ecology and Biogeography)

   Abstract AimAlthough species richness globally is likely to be declining, patterns in diversity at the regional scale depend on species gains within new habitats and species losses from previously inhabited areas. Our understanding of the processes associated with gains or losses remains poor, including whether these events exhibit immediate or delayed responses to environmental change. LocationThe study focuses on nine temperate marine ecosystems in North America. Time periodThe study period varies by region, but overall encompasses observations from 1970 to 2014. Major taxa studiedWe identified regional gains and losses for 577 marine fish and invertebrate species. MethodsFrom a total of 166,213 sampling events from bottom trawls across North America that informed 17,997 independent observations of species gains and losses, we built generalized linear mixed effects models to test whether lagged temperature can explain instances of gains and losses of marine fishes and invertebrates in North American continental shelf habitats. ResultsWe found that gains were less likely in years with high seasonality, consistent with seasonal extremes as a strong constraint on species occurrence. Losses were also negatively associated with high seasonality, but the response was delayed by 3 years. Main conclusionsEnvironmental conditions play a role in species occupancy across diverse temperate marine ecosystems. Immediate gains paired with delayed losses can drive transient increases in species richness during times of environmental change. Identifying the dynamics behind regional species gains and losses is an important step towards prediction of biodiversity changes across ecosystems. 

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5. Sea‐surface temperature anomalies mediate changes in fish richness and abundance in Atlantic and Gulf of Mexico estuaries

   https://doi.org/10.1111/jbi.14451  

   Oke, Tobi A.; Zhang, Stacy Y.; Keyser, Spencer R.; Yeager, Lauren A. (July 2022, Journal of Biogeography)

   Abstract AimAnthropogenic warming of marine systems has caused biological and physiological responses that are fundamentally altering ecosystem structure. Because estuaries exist at the land‐ocean interface, they are particularly vulnerable to the effects of ocean warming as they can undergo rapid biogeochemical and hydrological shifts due to climate and land‐use change. We explored how multiple components of estuarine fish diversity—turnover, richness, and abundance—have changed in the North Atlantic and Gulf of Mexico estuaries across space and time and the drivers of change. LocationNorth Atlantic and Gulf of Mexico. TaxaFish. MethodWe compiled long‐term (>30 years), continent‐wide fisheries independent trawl surveys conducted in estuaries—from the Gulf of Maine to the Gulf of Mexico (U.S. waters)—and combined these with climate and land‐use‐land‐cover data to examine trends and ecological drivers of fish richness, abundance and turnover using mixed‐effect models. ResultsSpecies richness, abundance and turnover have increased in North Atlantic and Gulf of Mexico estuaries in the last 30 years. These changes were mediated largely by sea‐surface temperature anomalies, especially in more northern estuaries where warming has been relatively pronounced. Main ConclusionThe increasing trajectory of turnover in many estuaries suggests that fish communities have changed fundamentally from the baselines. A fundamental change in community composition can lead to an irreversible trophic imbalance or alternative stable states among other outcomes. Thus, predicting how shifting community structures might influence food webs, ecosystem stability, and human resource use remain a pertinent task. 

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