Habitat Compression Research Articles

Blue and fin whale residence time and occupancy in Navy training and testing areas off the U.S. West Coast

Blue (Balaenoptera musculus) and fin (B. physalus) whales are prominent species in the California Current Ecosystem (CCE) using the area for migration and foraging. Blue whales migrate between tropical wintering grounds and higher latitude foraging grounds in the CCE, whereas fin whales may remain there year-round. We used Argos tracks of 182 blue (mean duration: 78 days) and 98 fin (mean duration: 35 days) whales tagged from 1994-2018 along the U.S. West Coast to examine residence time and occupancy in U.S. Navy training and testing areas. Bayesian hierarchical switching state-space model locations calculated from Argos tracks were used to provide residence time and proportion of tracking duration within each Navy area. We also calculated relative occupancy isopleths from the state space models, for both directed and non-directed movement, to assess spatial use of Navy areas. We then used generalized linear mixed models and beta regression to examine relationships between Navy area use and covariates, including six climate indices. Point Mugu Sea Range (PMSR) was the most heavily used Navy area by both species in terms of whale numbers, followed by the Southern California Range Complex (SOCAL). Residence time was longest in PMSR for blue whales and in the Northwest Training and Testing Study Area (NWTT) for fin whales. Blue whale use in PMSR was greater in summer versus autumn and for whales tagged in Southern versus Central California. Proportion of tracking duration decreased in all areas with increasing values of the Oceanic Niño Index (ONI), and in PMSR, with increasing values of the North Pacific Gyre Oscillation. Fin whale residence time was longer in PMSR during summer than winter or spring and decreased with increasing values of Habitat Compression Index and ONI. Proportion of tracking duration for fin whales was greatest in summer in PMSR and in winter in SOCAL and NWTT. Overlap of directed and non-directed movement was greatest in PMSR for both species. This assessment of blue and fin whale residence time and occupancy in Navy areas improves our understanding of potential threats these animals face, not only from military activities in Navy areas, but throughout the CCE.

Effects of urban eutrophication on pelagic habitat capacity in the Southern California Bight

Land-based nutrient inputs to the ocean have been linked to increased coastal productivity, subsurface acidification and O2 loss, even in upwelling systems like the Southern California Bight. However, whether eutrophication alters the [environment’s] capacity to support key taxa has yet to be evaluated for this region. Here, we assess the impact of land-based nutrient inputs on the availability of aerobic and calcifying habitat for key pelagic taxa using ocean model simulations. We find that acute, lethal conditions are not commonly induced in epipelagic surface waters, but that sublethal, ecologically relevant changes are pervasive. Land-based nutrient inputs reduce the potential aerobic and calcifier habitat during late summer, when viable habitat is at its seasonal minimum. A region of annually recurring habitat compression is predicted 30 – 90 km from the mainland, southeast of Santa Catalina Island. Here, both aerobic and calcifier habitat is vertically compressed by, on average, 25%, but can be as much as 60%. This effect can be traced to enhanced remineralization of organic matter that originates from the coast. These findings suggest that effects of land-based nutrients are not restricted to chemistry but extend to habitat capacity for multiple taxa of ecological and economic importance. Considerable uncertainty exists, however, in how this habitat compression translates to population-level effects.

You Shall Not Pass: The Pacific Oxygen Minimum Zone Creates a Boundary to Shortfin Mako Shark Distribution in the Eastern North Pacific Ocean

ABSTRACTAimShoaling of large oxygen minimum zones (OMZs) that form along eastern margins of the world's oceans can reduce habitat availability for some pelagic fishes. Our aim was to test the hypothesis that habitat compression caused by shoaling of the Pacific OMZ in tropical regions creates a boundary to the southern distribution of shortfin mako sharks (Isurus oxyrinchus) in the Eastern North Pacific Ocean.LocationEastern North Pacific and Western North Atlantic oceans.MethodsWe compared environmental conditions between areas used by satellite‐tagged mako sharks in the Eastern North Pacific, encompassing the world's largest OMZ, to those used in the Western North Atlantic where no OMZ is present. In the Pacific we quantified the effects of temperature and dissolved oxygen (DO) on depth use and tested if sharks spent less time in areas with strong habitat compression over the OMZ than expected by chance.ResultsThe southern distribution of sharks in the Pacific corresponded with the apex of OMZ shoaling in the North Equatorial Current. Sharks in the Atlantic occupied areas with warm surface temperatures (≥ 26°C) more often than the Pacific, and waters with these temperatures in the Atlantic had greater DO at depth. Sharks in the Pacific reduced time near the surface in warm temperatures and consistently avoided depths with low DO and spent less time in areas with strong habitat compression than expected by chance.Main ConclusionsThe combination of warm surface temperatures and shoaling of the OMZ creates a soft boundary to mako shark movements in the Eastern North Pacific Ocean. The expected expansion of OMZs due to climate change could have considerable impact on future distribution of mako sharks and other pelagic fish. As such, development of species distribution models to predict the effects of climate change on pelagic fish distributions should incorporate oxygen availability.

The vulnerability of sharks, skates, and rays to ocean deoxygenation: Physiological mechanisms, behavioral responses, and ecological impacts.

Levels of dissolved oxygen in open ocean and coastal waters are decreasing (ocean deoxygenation), with poorly understood effects on marine megafauna. All of the more than 1000 species of elasmobranchs (sharks, skates, and rays) are obligate water breathers, with a variety of life-history strategies and oxygen requirements. This review demonstrates that although many elasmobranchs typically avoid hypoxic water, they also appear capable of withstanding mild to moderate hypoxia with changes in activity, ventilatory responses, alterations to circulatory and hematological parameters, and morphological alterations to gill structures. However, such strategies may be insufficient to withstand severe, progressive, or prolonged hypoxia or anoxia where anaerobic metabolic pathways may be used for limited periods. As water temperatures increase with climate warming, ectothermic elasmobranchs will exhibit elevated metabolic rates and are likely to be less able to tolerate the effects of even mild hypoxia associated with deoxygenation. As a result, sustained hypoxic conditions in warmer coastal or surface-pelagic waters are likely to lead to shifts in elasmobranch distributions. Mass mortalities of elasmobranchs linked directly to deoxygenation have only rarely been observed but are likely underreported. One key concern is how reductions in habitat volume as a result of expanding hypoxia resulting from deoxygenation will influence interactions between elasmobranchs and industrial fisheries. Catch per unit of effort of threatened pelagic sharks by longline fisheries, for instance, has been shown to be higher above oxygen minimum zones compared to adjacent, normoxic regions, and attributed to vertical habitat compression of sharks overlapping with increased fishing effort. How a compound stressor such as marine heatwaves alters vulnerability to deoxygenation remains an open question. With over a third of elasmobranch species listed as endangered, a priority for conservation and management now lies in understanding and mitigating ocean deoxygenation effects in addition to population declines already occurring from overfishing.

Autumn vertical distribution of zooplankton in the oxygen minimum zone of the Eastern Tropical North Pacific

To confirm the Habitat Compression Hypothesis, a cruise to the Eastern Tropical North Pacific (ETNP) took place at the entrance of the Gulf of California, in an area rarely studied at the southern limit of the California Current, where it mixes with waters of the West Mexican Current and the Gulf of California. No significant day-night differences in the vertical distribution (0–500 m depth) of zooplankton were found based on 22 MOCNESS tows and, for the first time, a 48-h cycle of stratified zooplankton sampling. Most zooplankton groups were observed within the upper 100 m, above the oxycline, with oxygen concentrations as low as 45 μmol kg−1. Some California Current-influenced samples showed a slightly different vertical distribution. A ∼50% reduction in the number and abundance of 24 zooplankton groups was recorded within the Oxygen Minimum Zone, from 100 to 500 m depth. Vertical migrator's exceptions include some euphausiid species that migrate into the OMZ during the day. Principal Component Analyses showed that the vertical distribution of zooplankton is limited by oxygen, with a low zooplankton carbon density below ∼100 m depth within the OMZ. The difference between day and night for the upper 0–100 m layer was non-significant (U221 = 57; p = 0.947); however, the data showed great variability. Thus, zooplankton Carbon remains relatively constant, in the upper 100 m, and is available during day and night, in the studied area.

Habitat compression of an estuarine mytilid following half a century of streamflow decline

The distribution of species throughout estuaries is often regulated by salinity gradients, among other key environmental drivers. In many temperate estuaries, however, declining streamflow has led to increased marinization and thus potential habitat compression of some species. Since the mid-1970s, estuaries in south-western Australia have experienced among the greatest decline in streamflow in Australia due to a drying and warming climate. The resultant habitat modification would be particularly unfavourable to sessile fauna, such as mytilid mussels, which are unable to relocate due to their attachment to substrate via byssal threads. This study compared the settlement (and adult survival) of Black Pygmy Mussel Xenostrobus securis in the Swan-Canning Estuary with that described in this system sixty years earlier, over which time freshwater discharge declined by >50%. During the 1960s, settlement of X. securis occurred throughout much of the estuary, beginning in the estuary basin in November and in the upper Swan River in February/March as winter freshwater flow subsided and salinities increased. In contrast, in the current study (2019/2020), X. securis settlement was largely restricted to the upper zones of the estuary. Settlement of X. securis larvae also began much earlier, occurring in the upper Swan River in October, compared with February/March during the 1960s. This is consistent with the salinity tolerances of larval X. securis and declining streamflow, leading to increased marinization of the estuary basin and earlier encroachment of the salt-wedge upstream. In addition, the increased frequency of summer streamflow events in recent decades makes X. securis populations even more vulnerable to substantial mortalities caused by rapid dilution of salinity at warmer temperatures. Thus, the combination of habitat compression, from declining streamflow and increased occurrence of extreme summer rainfall events are likely to pose substantial problems for the survival of X. securis populations in this region into the future. The results of this study further our knowledge on the potential impacts of environmental change on sessile fauna and is of interest to environmental managers.

A preliminary life history traits analysis of sharks in the Sea of Marmara (Türkiye), where deoxygenation and habitat deterioration are raising concerns

Life history traits of 17 species of sharks occurring in the Sea of Marmara were analysed based on Gower’s distances, Principal Coordinate Analyses, and hierarchical clustering. The analysis shows that the sharks of the Sea of Marmara can ecologically be divided into several clusters. The increasing occurrence of sharks on the Marmara continental shelf, especially in the last few years, suggests that the expected habitat compression due to deoxygenation has begun to take place. This situation, which can be considered as a “habitat trap” for sharks, should be considered as a threat that may lead to shark mortalities due to the intensification of bycatches or even the intentional killing of sharks. Available results are sufficient to predict a disturbing future for sharks of the Sea of Marmara if the factors (deoxygenation, habitat loss, bycatch, etc.) threatening the overall ecosystem do not improve.

Oxygen and irradiance constraints on visual habitat in a changing ocean: The luminoxyscape

Oxygen and irradiance constraints on visual habitat in a changing ocean: The luminoxyscape

Habitat compression indices for monitoring ocean conditions and ecosystem impacts within coastal upwelling systems

Upwelling ecosystems are characterized by intense seasonal productivity that supports highly dynamic species populations, high diversity of mid and upper trophic levels, and a myriad of important fisheries. Climate variability and long-term change will impact upwelling intensity, timing and persistence, thereby potentially threatening resilience of coastal food webs and stability of ecosystem services. The spatial footprint of cool upwelled waters in the surface mixed-layer supports trophic transfer and ultimately the productivity of fisheries. The spatial area of upwelled water in eastern boundary upwelling systems can vary dramatically in response to both local and remote atmospheric forcing. These variations contribute to dynamic habitats that impact the structure, function, and spatial characteristics of marine ecosystems. We quantified the variability in “cool-water thermal habitat” area as a new ecological indicator, the Habitat Compression Index (HCI), for the nearshore (within 150 km of the coast) waters of the California Current Large Marine Ecosystem (CCLME). The HCI can be easily updated from ocean model products and satellite observations of sea surface temperature. We describe standardization of the HCI, regional variability, and evaluate HCI relationships with other indicators commonly used to inform ecosystem context within the CCLME. Importantly, our approach to calculating the HCI is easily extendable to other upwelling ecosystems. Further, we discuss the management context of the HCI such as assessing risk of whale entanglement in a highly profitable fishery, and implications for monitoring ecosystem shifts in coastal upwelling systems and the fisheries they support.

High-resolution post-release behaviour and recovery periods of two highly prized recreational sportfish: the blue marlin and sailfish

Abstract High recreational catch rates of istiophorid billfishes in the eastern tropical Pacific (ETP) have led to substantial eco-tourism derived economic benefits for the countries in the region, prompting many countries to mandate catch-and-release practices for recreational anglers. Previous estimates of billfish post-release behaviours and recovery periods after these physiologically stressful capture events, however, vary widely depending on the type of tag used. Using high-resolution, multi-sensor biologging tags, we provide a fine-scale, detailed view of the behaviour and recovery periods of blue marlin (Makaira nigricans; n = 9) and sailfish (Istiophorus platypterus, Istiophoridae; n = 9) caught in a typical recreational fishery in the ETP. Angling times ranged from 4 to 90 min, and fish were monitored for periods of 6–70 h after release. Blue marlin showed a characteristic long, deep dive immediately after release, with significantly greater duration associated with longer fight times, a behaviour not typical for sailfish. Diving depths were, however, much shallower than those previously reported for both species due to the shallow thermocline and oxycline present in the ETP. Data from 40 derived metrics from acceleration (i.e. tailbeat period, amplitude, pitch, etc.) and physical parameters (i.e. depth, speed, temperature, oxygen saturation, etc.) used to quantify a recovery period suggest blue marlin and sailfish recover 9.0 ± 3.2 and 4.9 ± 2.8 h after release, respectively. Our high-resolution assessment of post-release behaviour suggests that these billfish are capable of rapid physiological recovery after capture in recreational fisheries, and that catch-and-release practices like those used here can be an effective approach to conserve and sustain billfish populations in the ETP. Predicted climate change caused shallowing of the oxygen minimum zone, however, would increase the vertical habitat compression present in this region, potentially prolonging or inhibiting recovery.

Strong Habitat Compression by Extreme Shoaling Events of Hypoxic Waters in the Eastern Pacific

AbstractOcean deoxygenation has led to a measurable shoaling of subsurface hypoxic waters ([O2] < 60 mmol m−3) in the tropical Pacific and elsewhere. This shoaling compresses the vertical habitat of heterotrophic organisms between the well oxygenated surface and the hypoxic interface. Superimposed on this long‐term trend, natural variability can cause shorter‐term, extreme habitat compression events, which we term Transient Habitat Reduction Extreme Events (THREEs). Here, we investigate THREEs in the Eastern Pacific (EP) between 1979 and 2016 using output from a high‐resolution hindcast simulation with the coupled physical‐biogeochemical ocean model ROMS‐BEC. We identify THREEs on the basis of the hypoxic interface being shallower than the 99th percentile of its variability and requiring a minimum duration of five days. We find that THREEs compress the aerobic habitat by up to 50%–70% (locally exceeding 80%) in the subtropical and tropical EP and reach horizontal scales exceeding 300 km in the tropical EP. There, THREEs are pre‐conditioned by La Niña conditions and occur primarily in boreal winter and spring. In the subtropical EP, THREEs are associated with mesoscale eddies and occur independently of the season. 71% (32%) of all THREEs are characterized by unusually high acidity (cold) conditions (i.e., below the first percentile), thus constituting compound events. The strong habitat compression during THREEs is bound to lead to substantial changes in water column biogeochemistry, in food‐web interactions, and in ecosystem structure. Yet, so far, very little is known about the impact of these transient phenomena.

Distribution and biomass of gelatinous zooplankton in relation to an oxygen minimum zone and a shallow seamount in the Eastern Tropical North Atlantic Ocean

Physical and topographic characteristics can structure pelagic habitats and affect the plankton community composition. For example, oxygen minimum zones (OMZs) are expected to lead to a habitat compression for species with a high oxygen demand, while upwelling of nutrient-rich deep water at seamounts can locally increase productivity, especially in oligotrophic oceanic waters. Here we investigate the response of the gelatinous zooplankton (GZ) assemblage and biomass to differing oxygen conditions and to a seamount in the Eastern Tropical North Atlantic (ETNA) around the Cape Verde archipelago. A total of 16 GZ taxa (>1100 specimens) were found in the upper 1000 m with distinct species-specific differences, such as the absence of deep-living species Atolla wyvillei and Periphylla periphylla above the shallow seamount summit. Statistical analyses considering the most prominent groups, present at all stations, namely Beroe spp., hydromedusae (including Zygocanna vagans, Halicreas minimum, Colobonema sericeum, Solmissus spp.) and total GZ, showed a strong positive correlation of abundance with temperature for all groups, whereas oxygen had a weak negative correlation only with abundances of Beroe spp. and hydromedusae. To account for size differences between species, we established length-weight regressions and investigated total GZ biomass changes in relation to physical (OMZ) and topographic characteristics. The highest GZ biomass was observed at depths of lowest oxygen concentrations and deepest depth strata at the southeastern flank of the seamount and at two stations south of the Cape Verde archipelago. Our data suggest that, irrespective of their patchy distribution, GZ organisms are ubiquitous food web members of the ETNA, and their habitat includes waters of low oxygen content.

Western Gull Foraging Behavior as an Ecosystem State Indicator in Coastal California

With accelerating climate variability and change, novel approaches are needed to warn managers of changing ecosystem state and to identify appropriate management actions. One strategy is using indicator species—like seabirds as ecosystem sentinels—to monitor changes in marine environments. Here, we explore the utility of western gulls (Larus occidentalis) breeding on Southeast Farallon Island as a proxy of ecosystem state in coastal California by investigating the interannual variability in gull foraging behavior from 2013 to 2019 in relation to upwelling conditions, prey abundances, and overlap with humpback whales (Megaptera novaeangliae) as gulls frequently feed in association with whales. Western gulls have a flexible diet and forage on land and at-sea. We combined gull GPS tracking data during the incubation phase, ecosystem survey data on multiple predator and prey species, and derived oceanographic upwelling products. When foraging at sea, gulls overlapped with cool upwelled waters. During 2015–2017, 25% more gull foraging trips visited land than in other years, where land trips were on average ∼8 h longer and 40% further than sea trips, which coincided with high compression of coastally upwelled waters (habitat compression) in 2015–2016. Gull foraging behavior was related to local prey abundances, where more foraging occurred near shore or on land when prey abundances were low. However, visual surveys indicated that ∼70% of humpback whale observations co-occurred with gulls, and the year with the most foraging on land (2017) corresponded to regionally low relative whale abundances, suggesting gull movement patterns could be an indicator of whale presence. Further, both whales and gulls forage near-shore under high upwelling habitat compression and low krill abundance. Hence, the deployment of year-round tags on gulls with the capability of near real-time data accessibility could provide important fine-scale metrics for conservation and management of the threatened yet recovering eastern Pacific humpback whale population between infrequent and coarse surveys. Entanglement in fishing gear and ship strikes are major inhibitors to whale recovery and have increased concomitantly with human use of ocean resources. Moreover, as climate variability and change increase, novel indicators should be explored and implemented to inform marine spatial planning and protect species across multiple scales from new risks.

Shallow marine ecosystem collapse and recovery during the Paleocene-Eocene Thermal Maximum

The Paleocene-Eocene Thermal Maximum (PETM), the most well-studied transient hyperthermal event in Earth history, is characterized by prominent and dynamic changes in global marine ecosystems. Understanding such biotic responses provides valuable insights into future scenarios in the face of anthropogenic warming. However, evidence of the PETM biotic responses is largely biased towards deep-sea records, whereas shallow-marine evidence remains scarce and elusive. Here we investigate a shallow-marine microfaunal record from Maryland, eastern United States, to comprehensively document the shallow-marine biotic response to the PETM. We applied birth-death modeling to estimate the local diversity dynamics, combined with evaluation of time-variable preservation artifacts. We discovered strong increase of species disappearance and appearance predating the onset and at the final recovery phase of the PETM, respectively. Our paleoecological analyses indicate that bathymetric habitat compression due to extreme warmth and oxygen minimum zone expansion caused shallow-marine benthic species extirpation and ecosystem perturbation during the PETM; and that rapid recovery and diversification followed the PETM disaster, thus contributing new understanding to the shallow-marine biotic changes in a broad context of global warming. • Local extinction event predates the Paleocene-Eocene Thermal Maximum (PETM) onset. • Rapid local diversification occurred when the PETM anomalies terminated. • A clear perturbation-recovery pattern of the shallow-marine ecosystem across PETM. • Habitat compression by warming and deoxygenation led to local PETM extinction. • Biodiversity loss by hyperthermal events may be irreversible.

Moving on up: Vertical distribution shifts in rocky reef fish species during climate-driven decline in dissolved oxygen from 1995 to 2009.

Anthropogenic climate change has resulted in warming temperatures and reduced oxygen concentrations in the global oceans. Much remains unknown on the impacts of reduced oxygen concentrations on the biology and distribution of marine fishes. In the Southern California Channel Islands, visual fish surveys were conducted frequently in a manned submersible at three rocky reefs between 1995 and 2009. This area is characterized by a steep bathymetric gradient, with the surveyed sites Anacapa Passage, Footprint and Piggy Bank corresponding to depths near 50, 150 and 300 m. Poisson models were developed for each fish species observed consistently in this network of rocky reefs to determine the impact of depth and year on fish peak distribution. The interaction of depth and year was significant in 23 fish types, with 19 of the modelled peak distributions shifting to a shallower depth over the surveyed time period. Across the 23 fish types, the peak distribution shoaled at an average rate of 8.7 m of vertical depth per decade. Many of the species included in the study, including California sheephead, copper rockfish and blue rockfish, are targeted by commercial and recreational fisheries. CalCOFI hydrographic samples are used to demonstrate significant declines in dissolved oxygen at stations near the survey sites which are forced by a combination of natural multidecadal oscillations and anthropogenic climate change. This study demonstrates in situ fish depth distribution shifts over a 15‐year period concurrent with oxygen decline. Climate‐driven distribution shifts in response to deoxygenation have important implications for fisheries management, including habitat reduction, habitat compression, novel trophic dynamics and reduced body condition. Continued efforts to predict the formation and severity of hypoxic zones and their impact on fisheries dynamics will be essential to guiding effective placement of protected areas and fisheries regulations.

Habitat isolation and the cues of three remote predators differentially modulate prey colonization dynamics in pond landscapes.

Recent evidence suggests predators may change colonization rates of prey in nearby predator-free patches as an example of context-dependent habitat selection. Such remote predator effects can be positive when colonizers are redirected to nearby patches (habitat compression), or negative when nearby patches are avoided (risk contagion). However, it is unknown to what extent such responses are predator- and prey-specific and change with increasing distance from predator patches. We evaluated how cues of fish, backswimmers and dragonfly larvae affect habitat selection in replicated pond landscapes with predator-free patches located at increasing distances from a predator patch. We found evidence for risk contagion and compression, but spatial colonization patterns were both predator- and prey-specific. The mosquito Culex pipiens and water beetle Hydraena testacea avoided patches next to patches with dragonfly larvae (i.e. risk contagion). Predator-free patches next to patches with backswimmers were avoided only by mosquitoes. Mosquitoes preferentially colonized patches at some distance from a fish or backswimmer patch (i.e. habitat compression). Colonization patterns of beetles also suggested habitat compression, although reward contagion could not be fully excluded as an alternative explanation. Water beetles preferred the most isolated patches regardless of whether predators were present in the landscape, showing that patch position in a landscape alone affects colonization. We conclude that habitat selection can be a complex product of patch isolation and the combined effects of different local and remote cues complicate current attempts to predict the distribution of mobile organisms in landscapes.

Physiological and ecological consequences of the water optical properties degradation on reef corals

Degradation of water optical properties due to anthropogenic disturbances is a common phenomenon in coastal waters globally. Although this condition is associated with multiple drivers that affect corals health in multiple ways, its effect on light availability and photosynthetic energy acquisition has been largely neglected. Here, we describe how declining the water optical quality in a coastal reef exposed to a turbid plume of water originating from a man-made channel compromises the functionality of the keystone coral species Orbicella faveolata. We found highly variable water optical conditions with significant effects on the light quantity and quality available for corals. Low-light phenotypes close to theoretical limits of photoacclimation were found at shallow depths as a result of reduced light penetration. The estimated photosynthetically fixed energy depletion with increasing depth was associated with patterns of colony mortality and vertical habitat compression. A numerical model illustrates the potential effect of the progressive water quality degradation on coral mortality and population decline along the depth gradient. Collectively, our findings suggest that preserving the water properties seeking to maximize light penetration through the water column is essential for maintaining the coral reef structure and associated ecosystem services.

Pelagic Biodiversity, Ecosystem Function, and Services: An Integrated Observing and Modeling Approach

Our synthesis combines inferences from a long-term fisheries monitoring survey and principles of ecosystem oceanography to inform and benefit biodiversity monitoring and modeling studies within the California Current Large Marine Ecosystem. We review the history, research, and application of the Rockfish Recruitment and Ecosystem Assessment Survey, highlighting how one survey of life can illuminate understanding of pelagic biodiversity patterns and ecosystem function (from micronekton to top predators to ecosystem services) that may be easily extended to other surveys to strengthen observation networks. Biodiversity is often used as the standard for understanding ecosystem resilience to climate or anthropogenic disturbances. This concept is central to our review, and we examine it in relation to complex impacts resulting from a recent climate event (a marine heatwave) on biodiversity, ecosystem function, and socioeconomic services. We present a system of interconnected modules that summarize and illustrate patterns of pelagic biodiversity using a phylogenetic approach, known modulations and environmental drivers of variability (i.e., source waters, habitat compression, and ecosystem shifts), remote sensing and modeling tools for monitoring biodiversity (i.e., seascapes and krill hotspot models), and the status of top predator biodiversity. We use these modules to summarize connections between biodiversity and ecosystem services provided. Following each module, a brief discussion of questions raised and recommendations for future studies and partnerships is provided to improve future integrative biodiversity monitoring. Additionally, we invested in promoting data accessibility and outreach, resulting in several data visualization and ecosystem context tools for biodiversity monitoring and fisheries management. We advocate that a diverse integrated ecosystem approach should result in fewer ecological surprises by putting past events and surprises into context, and thus better anticipating those yet to arrive. Building partnerships among researchers and coastal communities will result in increased capacity of analytical tools and perspectives to ensure sustainable use of fishery resources, while strengthening the resilience of fishing communities.

Coronavirus from cities to forests: mapping vulnerable interfaces and hotspots for SARS-CoV-2 spillover from humans to biodiversity

BackgroundWith the continuous spreading of SARS-CoV-2 globally, the probability for interactions between humans who are infected and wildlife tends to grow intensely, as well as the likelihood of viral spillover from humans to biodiversity. This aspect is of great concern for wildlife conservation and human health, because the list of highly susceptible animal groups that have contracted SARS-CoV-2 (bats, mustelids, and primates) is large and, once infected, these groups can act as vectors and reservoirs, becoming a substrate for viral mutations and recombinations and boosting the risk of new strains emerging, which can return to humans as new diseases. Little is known about the inducing factors facilitating coronavirus spillover from one species to another, but it can be argued that interface zones between wild fauna and humans, which are narrow edges between anthropic (cities, roads, parks, ecotourism sites, and agricultural frontiers) and sylvatic habitat, are zones of increased interaction between humans and wild animals, and thus have a higher probability of viral spillover events than other areas. In a similar context, the habitat compression by forest fragmentation also brings species and infected beings closer, reducing their home ranges and intensifying the risk of spillover among wild populations. Therefore, on the basis of the premise for zoonosis—the greater human–animal interaction, the greater risk of viral spillover—we aimed to identify the most and least susceptible areas to viral spillover in Brazil. MethodsWe developed an approach combining ecological modelling (Biomod2: modelling habitat suitability for 158 bat and 49 primate species) and geographical information systems (by using demographic indicators, roads, and related variables) to map the most and least susceptible areas to spillover in Brazil. This map indicates priority areas for serological surveillance of fauna for monitoring the spillover and circulation of SARS-CoV-2 strains and variants in Brazilian biodiversity. FindingsAmong our most relevant preliminary results, we found that forested areas surrounding the São Paulo Metropolitan Area are among the most susceptible areas for spillover. This resulted from the combination of high contaminated human density and high density of non-human primates interacting with humans in these transitional areas. InterpretationBecause of the high resolution of the results, the map can be useful for action planning and decision making in conservation and health, since susceptible areas denote not only a greater risk of virus jumping from humans to animals, but also of coronaviruses returning from fauna to humans in new viral strains. FundingFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP; 2019/12988-7 and 2018/14389-0).

Euphausiid spatial displacements and habitat shifts in the southern California Current System in response to El Niño variability

We analyzed spatial distributions of 10 euphausiid species in the southern California Current System across seven El Niño events (1951–2018) and the 2014–15 Warm Anomaly to determine variations in habitat utilization and reproduction during Eastern Pacific (EP) and Central Pacific (CP) Niños. Our goal was to characterize the main forcing mechanisms by which El Niño events influence these dominant species. Our findings suggest cool-water euphausiids respond predominantly to changing in situ habitat conditions during El Niño, while subtropical species require initial advection to increase in the southern CCS. Cool-water coastally-associated species (Euphausia pacifica, Thysanoessa spinifera) compress shoreward and retract poleward to upwelling waters during EP Niños, likely in response to offshore warming. A subtropical coastal species (Nyctiphanes simplex) extends poleward nearshore during EP Niños, suggesting anomalous advection, but increases only moderately and variably off southern California during CP Niños. A Tropical Pacific-Baja California species (Euphausia eximia) only appears off southern California in spring during El Niño years (EP, some CP), suggesting direct advection and low tolerance for cooler, fresher conditions. Subtropical offshore species (Euphausia gibboides, Euphausia recurva, Stylocheiron affine, Euphausia hemigibba) expand shoreward during most Niños (strongest during 2014–15 Warm Anomaly) and show moderate in situ post-event persistence, suggesting combined influence of advection and temporarily favorable habitat nearshore. Regionwide temperate species (Nematoscelis difficilis, Thysanoessa gregaria) contract only moderately shoreward during some Niños. Predictions of Year 2100 distributions using generalized additive models suggest future non-Niño conditions and CP Niños will produce regionwide in situ increases in subtropical species and moderate poleward and onshore expansions, while EP Niños will produce continued nearshore habitat compression and reduced abundance of coastal species. Understanding zooplankton spatial responses to El Niño can help predict community compositional shifts under other ocean changes (e.g., long-term trends, basin-wide warm anomalies).