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Often, catch and release regulations are meant to maximize a fisheries potential to create trophy fish. I evaluated adult Brown Trout populations at five locations within Rapid Creek within Rapid City, SD over a two-year period. In each year, one of these locations was within a catch and release area, while two were outside. In 2012, density and biomass estimates were higher in a site located outside of the catch and release area. Additionally, size structure within the catch and release area was only significantly larger than one of the two sites outside of the regulation area. Mean relative weight values were inversely related to density estimates, with the lowest density sites having the highest mean relative weights. Similarly, a site outside of the catch and release area had the highest abundance and biomass estimates in 2013. The cumulative length distribution was significantly different between the site within the catch and release area and the two located outside. Relative weight was significantly higher in the catch and release area than the two sites outside. As population characteristics within the catch and release area were not consistently better than outside, it is more likely that factors such as habitat and density dependence are impacting the Brown Trout population more than the regulation itself.

The Chilean water penny genus Tychepsephus Waterhouse, 1876 is revised, with descriptions and photographic illustrations of life stages including two larval morphotypes, the pupa of one morphotype, and adults of two species. The pupa of Tychepsephus has not been reported previously. Tychepsephus cekalovicisp. nov. is described, and Ectopria (Chilectopria) grandis Pic, 1947, syn. nov. is proposed as a new synonym of Tychepsephus felix Waterhouse, 1876, which is redescribed. Taxonomic treatment of the adults of both species includes images of the habitus of males and females, morphological variation, and male and female genitalia. Males and females are sexually dimorphic. Information on the habitat of Tychepsephus is provided and illustrated with photographs, and the known geographic distribution of the two species is mapped. The occurrence of Tychepsephus in Argentina is reported; therefore, the genus no longer can be considered endemic to Chile. The taxonomic status and geographic distribution in South America of other species of Psephenidae, particularly members of the subfamily Eubriinae, is reviewed.

Knowledge of reproductive biology and life-history traits of populations exploited by fisheries is important for their sustainable management. We investigated the life-history traits of Trichiurus lepturus (largehead hairtail) in south-eastern Australia; a region of low exploitation for this otherwise heavily exploited circumglobal species, to investigate whether there were differences in the reproductive biology and life-history traits in the south-east Australian population compared with those in other regions. We also used histological sections to examine male and female gonads at a microscopic level. Trichiurus lepturus in south-eastern Australia had a greater maximum length (193 cm total length (TL)), matured at a larger length (108 cm TL at 50% mature) and had a spawning period (March to September, Austral winter) that was inconsistent with other regions. The overall sex ratio of 1:0.4 females: males was consistent with a female dominant sex ratio observed in other regions, particularly in larger length classes. However, females in the current study dominated samples from both estuarine and coastal habitats, as well as during the spawning and non-spawning periods, which is not consistent with the patterns found in other regions. Differences in south-eastern Australia may relate to limited fishing pressure, genetic variation, or differences in environmental factors that influence reproductive development, including temperature, trophic resources and habitat.

Urban expansions into natural habitats have forced many carnivores to adapt to the modified areas; however, our understanding of their ecology in such areas is limited. The Indian fox (Vulpes bengalensis) is a small carnivore species that can adapt and exploit urban areas due to its generalist nature, but there is a paucity of data on Indian foxes in these human-modified areas. To understand the resource requirement of Indian foxes in urban habitats, we conducted a diet analysis by examining 119 scats of Indian foxes in a peri-urban habitat of Baripada town, Odisha, eastern India. To determine the diet composition of Indian foxes, we analyzed scat contents by their frequency occurrence (%FO), the relative frequency of occurrence (%RF) and mean percent volume (%Vm). Indian foxes consumed a wide range of food categories, including arthropods, rodents, reptiles, birds, plant parts and anthropogenic resources. In %Vm, rodents showed the highest volume, followed by polythene, Spondias pinnata fruit and Coleoptera. We found anthropogenic foods in considerable quantities, including polythene and paper. The diet of Indian foxes indicates that the species has opportunistic and generalist feeding habits consisting primarily of easily accessible foods. Furthermore, management efforts should focus on the proper management of waste and control of anthropogenic food sources in urban habitats.

Understanding the factors that allow a species to expand its range and adapt to changing habitats is essential for mitigating anthropogenic change. We evaluated how behavior and cognition facilitate colonization of new environments and evolve post establishment during natural biological invasions. Marine threespined sticklebacks are expert colonists with a penchant for invading freshwater environments and rapidly adapting to them. However, the role of behavior in facilitating rapid adaptation in this system has received little attention. By rearing replicate populations of sticklebacks under common garden conditions in the lab, we tested the hypothesis that boldness is favored in dispersers and that neophilia and flexibility are favored in recently-arrived immigrants. We found that dispersing populations comprised bold individuals, while sticklebacks from the invaded region were flexible in their behavior. Moreover, boldness and flexibility were negatively correlated with each another at the individual, family and population levels. Multiple lines of evidence suggest that there is a heritable component to boldness and flexibility, therefore their divergence is likely to be evolutionary in origin. If boldness is favored in invaders during the initial dispersal stage, while flexibility is favored in recent immigrants during the establishment stage, then the link between boldness and flexibility could generate positive correlations between successes during both the dispersal and establishment stages, and therefore play a key role in facilitating colonization success in this important model organism. SIGNIFICANCE STATEMENTFor a species to expand its range, it needs to be good at dispersing and also capable of exploiting resources and adapting to different environments. Therefore, behavioral and cognitive traits such as boldness, neophilia and behavioral flexibility could play key roles in facilitating invasion success. Here, we show that dispersing sticklebacks are bold, while sticklebacks that have recently established in a new region are flexible. Moreover, boldness and flexibility are negatively correlated with one another. If boldness is favored in dispersers while flexibility is favored in immigrants, then this behavioral syndrome could play a heretofore underappreciated role in facilitating rapid adaptation in this important model organism.

En un ecosistema degradado, que actualmente es objeto de restauración, analizar de manera detallada la estructura de la vegetación y describir su relación con especies de aves es muy relevante para su manejo. El análisis de la arquitectura de las plantas es un método visual para describir la estructura de la vegetación como resultado de su estrategia de crecimiento. Por medio de este método se analizó la oferta de hábitat de las aves insectívoras Myrmeciza longipes (hormiguero ventriblanco), Thamnophilus doliatus (batará rayado) y Synallaxis albescens (pijuí pechiblanco) como parte de un estudio poblacional y de calidad de hábitat en un remanente de bosque seco tropical de 11 079 hectáreas, en Huila, Colombia. Por medio de conteos y también con la información secundaria recopilada, se estableció cómo estas especies usan los diferentes estratos de la vegetación. Teniendo en cuenta que árboles con más perchas incrementan el forrajeo de aves insectívoras, que más perchas significan mayor refugio para las aves, y también que mayor cruce de perchas posibilitan la aparición de horquetas para el anclaje de nidos de estas especies, en 186 parcelas se determinó que la zona está dominada por siete modelos arquitectónicos, divididos en tres grupos según su oferta potencial de recursos del hábitat para las tres especies: 1) modelos arquitectónicos Roux, Petit y Prevost con una calidad alta; 2) modelos arquitectónicos Koriba y Nozerán con una calidad intermedia; y 3) modelos arquitectónicos McClure y Holttum con una calidad muy baja.

The Early Pleistocene is an epoch where wide environmental changes, driven by climate instabilities, were registered by multiple lines of evidence in different chronostratigraphic records, both continental and marine. Among these records, small mammals are one of the most reliable for understanding how faunal assemblages responded to the climate shifts. One of the key regions for this epoch in the European framework is the north-eastern Italian Peninsula, which was long considered as an ecotonal zone and crossroad between Central and Mediterranean Europe. In this region, Rivoli Veronese (Verona, north-eastern Italy), an Early Pleistocene site with a highly diversified assemblage, has always been considered one of the most important sites for the biochronology of the Italian Peninsula. Here we present the taxonomic study of the Early Pleistocene insectivores, bats, and rodents from this site, as well as the environmental and climatic reconstruction using the Taxonomical Habitat Index, the Habitat Weighting, and the Bioclimatic model. In the rich Rivoli Veronese assemblage, composed of 27 taxa, important biochronology markers, such as Mimomys pitymyoides, Mimomys tornensis, and Mimomys pliocaenicus were recognized. The earliest occurrences in Europe of Sorex praealpinus and Dinaromys genus were also documented as well as a new fossil mole species, Talpa sp. nov. Comparison with other European small mammal assemblages of the Early Pleistocene have allowed us to relate Rivoli Veronese to the early Late Villanyian Age. The persistence of Pliocene relicts, such as Rhagapodemus cf. frequens, and Pliopetaurista cf. pliocaenica, together with Early Pleistocene species is a remarkable feature of this site. This is also reflected in the environment which was still mainly forested but with spreading open areas and wetlands mainly in the form of water streams. The climate values shows that the conditions were similar to the current ones but the comparison with the near and recent Monte La Mesa assemblage, dated to Early Biharian (beginning of the Calabrian Stage), and the appearance of several taxa related to open landscapes show that a cooling and arid trend in climate was already settled in the region during the Gelasian.

Leaf toughness is an important functional trait that confers resistance to herbivory and mechanical damage. We sought to determine how species composition, climate, seasonality, and nutrient availability influence leaf toughness in two types of tundra in northern Alaska. We measured leaf toughness as force to punch for 11 species of Arctic plants in tussock tundra and dry heath tundra at 17 sites distributed along a latitudinal gradient. Rubus chamaemorus L. and the graminoids occupied opposite ends of the leaf toughness spectrum, with Rubus chamaemorus requiring the least force to punch, whereas one of the graminoids, Eriophorum vaginatum L., required the most. Leaf toughness increased with mean summer temperature for Eriophorum vaginatum and Betula nana L., whereas it declined with warmer temperatures for the other species. Toughness of mature leaves of Eriophorum vaginatum did not vary through the growing season but declined significantly after senescence. Application of N and P fertilizer in an experimental site decreased leaf toughness in three species but had no effect on four others. Leaf toughness of four out of five species in dry heath was greater than for the same species in tussock tundra, but there was no difference in community-weighted mean toughness between tussock tundra and dry heath.

In sub–Saharan Africa, Tanzania is one of the countries of global significance for biodiversity conservation. However, some plants in Tanzania, including Aloe species, are critically endangered. Tanzanian critically endangered aloes have generally limited distribution ranges and are represented by very small populations in the wild. Knowledge about their conservation, distribution, ecology and population status is also limited in the country. We carried out field surveys to assess conservation, distribution and ecological habitat of Tanzanian critically endangered aloes (CEAs) i.e. Aloe boscawenii, Aloe flexilifolia, Aloe leptosiphon and Aloe dorotheae. The study aimed to assess (i) the current population of CEAs, (ii) ecological habitats of CEAs and (iii) awareness of local people about CEAs and their conservation status. A stratified random meander survey was used to assess CEAs distribution and abundance. Their abundance was estimated by counting the number of each individual found in the area. Data on ecological habitat of CEAs were collected using direct field observations while recording signs of anthropogenic activities that threaten their survival. We recorded 141, 58 and 61 individuals of A. dorotheae, A. leptosiphon and A. flexilifolia, respectively. Most A. leptosiphon and A. flexilifolia individuals were hanging on bare rocks on higher cliffs. Moreover, we found that conservation initiatives to protect CEAs are absent in the study areas. Besides, local people were uninformed of the existence of CEAs and their conservation status. Our findings generally inform conservation gap regarding aloe species and their ecological habitats.

Spatial segregation of closely related species is usually attributed to differences in stress tolerance and competitive ability. For both animals and plants, reproductive interactions between close relatives can impose a fitness cost that is more detrimental to the rarer species. Frequencydependent mating interactions may thus prevent the establishment of immigrants within heterospecific populations, maintaining spatial segregation of species. Despite strong spatial segregation in natural populations, two sympatric California monkeyflowers(Mimulus nudatusandM. guttatus) survive and reproduce in the other’s habitat when transplanted reciprocally. We hypothesized that a frequency-dependent mating disadvantage maintains spatial segregation of these monkeyflowers during natural immigration. To evaluate this hypothesis, we performed two field experiments. First, we experimentally added immigrants in varying numbers to sites dominated by heterospecifics. Second, we reciprocally transplanted arrays of varying resident and immigrant frequencies. Immigrant seed viability decreased with conspecific rarity forM. guttatus, but notM. nudatus. We observed immigrant minority disadvantage for both species, but driven by different factors– frequency-dependent hybridization forM. guttatus, and competition for resources and/or pollinators forM. nudatus.Overall, our results suggest a major role for reproductive interference in spatial segregation that should be evaluated along with stress tolerance and competitive ability.

Although human fragmentation of freshwater habitats is ubiquitous, the genetic consequences of isolation and a roadmap to address them are poorly documented for most fishes. This is unfortunate, because translocation for genetic rescue could help mitigate problems. We used genetic data (32 SNPs) from 203 populations of westslope cutthroat trout (Oncorhynchus clarkii lewisi) to (1) document the effect of fragmentation on genetic variation and population structure, (2) identify candidate populations for genetic rescue, and (3) quantify the potential benefits of strategic translocation efforts. Human-isolated populations had substantially lower genetic variation and elevated genetic differentiation, indicating that many populations are strongly influenced by random genetic drift. Based on simple criteria, 23 populations were candidates for genetic rescue, which represented a majority (51%) of suitable populations in one major region (Missouri drainage). Population genetic theory suggests that translocation of a small number of individuals (∼5 adults) from nearby populations could dramatically increase heterozygosity by up to 58% (average across populations). This effort provides a clear template for future conservation of westslope cutthroat trout, while simultaneously highlighting the potential need for similar efforts in many freshwater species.

The Cape Bathurst polynya and flaw lead (CBP) are major, predictable habitat features with ≤15% ice cover in an otherwise ice-covered Beaufort Sea, and thought to provide hunting opportunities for polar bears (Ursus maritimus Phipps, 1774). We assessed 78 adult (female; with and without cubs) and subadult (male and female) polar bears’ use of the CBP from October to June 2007–2014. The CBP was up to 725 km wide in autumn, ice-covered in winter, and

The current study is the first to document a vast swarm of the pelagic tunicate Thalia democratica inshore of the Egyptian Mediterranean waters. On the May 05, 2021, a swarm of the Salpida T. democratica was discovered inshore of the coast of Stanley. The swarm coincided with a red tide bloom in the research area. The documented species is given a brief redescription with illustrative photographs, taxonomic annotations, habitat notes, and distribution.

This study conducted from January to June 2018, attempts to determine the density, habitat preferences and attitudes of people towards Gekko gecko and its impact on the conservation of this species in human-dominated landscapes in Sonitpur district, Assam. Eight villages at different distances from Nameri Tiger Reserve were chosen for the study. The line transects analyzed using DISTANCE software estimated a density of 7.99 individuals ha−1 in fringe villages of Nameri Tiger Reserve which also had higher number of host tree species diversity with higher basal area and density as compared to that of villages distant from Nameri Tiger Reserve. Gekko gecko was sighted on a total of 30 trees (6 species, 2 families), the highest being Ficus rumphii (40%). Maximum sightings of Gekko gecko was done on trees (67%). The occurrence of Gekko gecko was highly influenced by distance from forest (12%), followed by source of income (11%) and gender (4%). The majority of the respondents (53.54%) revealed that Gekko gecko occurred naturally in the homegardens implying that homegardens provided the habitat that can support the populations of Gekko gecko. But 46.45% of the respondents reported that they were adopted (62.16% in villages distant from Nameri Tiger Reserve), which raises serious concerns about the conservation of Gekko gecko in homegardens. Though, majority of the people knew that it is illegal to trade Gekko gecko, the financial benefits of its trade is very alluring. To make homegardens more favourable for the survival of Gekko gecko there should be strict law enforcement, upgradation of the species in the IUCN Red List and options for alternative livelihood.

Periophthalmus chrysospilos is an amphibious fish and considered candidates of typical aquarium fish in the Mekong Delta (MD), Vietnam. It is a species that is facing overfishing. Unfortunately, the data on its length-weight relationship (LWR), growth pattern, and condition factor are limited. The present study lasted from April 2020 to March 2021 to contribute knowledge of these data. A collection of 1,031 specimens (508 females and 523 males) was obtained from estuarine and coastal regions. The results showed that the fish total length (TL) and weight (W) were significantly different between sexes, seasons, and sites. In order to determine LWRs, weights of males and females in two sizes, seasons, four sites, and twelve months were estimated from the fish given lengths. The species displayed temporal variation in growth patterns as b values ranged from 2.87 ± 0.12 SE to 3.46 ± 0.07 SE. It generally showed positive allometric growth as b (3.22 ± 0.02 SE) was higher than the threshold of three. The fish body conditional factor was close to the well-being value of one and was not influenced by sex, but by season, site and month variations. The findings concluded that the species was well adapted to its habitat.

Habitat fragmentation – in terms of a combination of habitat loss and separation – is a major threat to the renosterveld of the Cape Floristic Region (CFR) of which 85% has been transformed, mostly for agriculture. The effects thereof has not been well studied, in particular in the Eastern inland areas. In this study we seek to understand how habitat patch size influence visitation rate of pollinators of winter flowering plants in the Eastern-Ruens Shale Renosterveld of the Overberg region. We compared pollinator visitation rates to flowers of Relhania garnotii, Clutia sp. nov and Oxalis purpurea between small (0–4.9 ha) and medium (5–15 ha) sized fragments, and compared these to the last large intact protected area, the Haarwegskloof Renosterveld Reserve (>500 ha), termed mainland. We classified degree of isolation among fragments into high (>100 m) and low (

In my Ph.D. thesis I investigated a few factors that influence the habitat use of the European ground squirrel (Spermophilus citellus; as EGS hereafter) and the Gunnison’s prairie dog (Cynomys gunnisoni; as GPD hereafter), two ecologically similar ground dwelling sciurids. I attempted to show the importance of a few extrinsic and intrinsic mechanisms by which the association between the habitat and ground squirrels is maintained. EGS show a strong preference for fresh Festuca pseudovina. Insulation property of the squirrels’ fresh grass nests was superior to nests constructed from dry grass only. Our results suggest that squirrels may rely on dominant xeromorphic fescues of dry meadows because of their importance to nest building. Consequently, it can be assumed that populations will expand to unoccupied areas and survive for longer-time and reintroductions will be successful if the habitat is characterized by fescues. GPD use mounds for vigilance and it increases with taller vegetation. Vigilance is more frequent and directed outward by individuals on the periphery than those in the interior of the colony. GPD we excavates about 6.5-16.6 m3/ ha/ year, so they can be considered as ecosystem-engineers indeed. It is possible to estimate volume of burrows with our calculation method by measuring the amount of subsoil displaced in the mound. Information on volume of burrows can be applied to monitor how the size of natural or artificial burrows changes. Results of translocation experiments showed that release time should correspond to the morning activity peak of EGS, the artificial burrow with retention cap prevents panic reactions, and angled artificial burrows and medium-height grass (18 cm ± 12 SD) favour translocation success in the critical period after release. Genetic diversity of EGS populations from Hungary, Romania and Austria was higher than that of the Czech populations but all studied populations have relatively low heterozygosity in comparison with other sciurids. Nevertheless, and perhaps as a result of simultaneously acting factors the genetic diversity of populations of neighbouring regions can differ significantly. To summarize, ground squirrels are sensitive to changes in environmental factors, facilitating fluctuations in population size. Ecological sensitivity, interacting with “scramble-competition polygyny”, implies a more serious threat to the persistence of the species than possible negative effects of translocations as regards the genetic aspects. This notion is illustrated by the ongoing, rising isolation and disappearance of colonies.

Understanding dreissenid mussel population dynamics and their impacts on lake ecosystems requires quantifying individual growth across a range of habitats. Most dreissenid mussel growth rates have been estimated in nutrient rich or nearshore environments, but mussels have continued to expand into deep, cold, low-nutrient habitats of the Great Lakes. We measured annual quagga mussel (Dreissena rostriformis bugensis) growth at 15 m, 45 m, and 90 m in Lake Ontario using caged mussels near Oswego, New York, USA from June 2018 to May 2019. Quagga mussel growth (starting size 12 mm) was greatest at 15 m (mean shell length increase = 10.2 mm), and was lower at 45 m (5.9 mm) and 90 m (0.7 mm). Caged mussels were obtained from near the 90-m site and those reared at 15 and 45 m developed thicker shells than those that were caged at 90 m. We observed relatively high colonization by quagga and, to a lesser degree, zebra mussels (Dreissena polymorpha) at 15 m, very few colonizers at 45 m, and none at 90 m. Higher growth potential, but low natural mussel densities observed at 15 m and 45 m suggest factors other than growth limit dreissenid abundance at these depths. The relatively slow dreissenid growth rates observed in offshore habitats are consistent with the gradual abundance increases documented in these zones across the Great Lakes and suggest new mussels that become established in these habitats may contribute to ecosystem effects for decades.

Nearshore marine habitats are critical for a variety of commercially important fish species, but assessing fish communities in these habitats is costly and time-intensive. Here, we leverage eDNA metabarcoding to characterize nearshore fish communities near Juneau, Alaska, USA, a high-latitude environment with large tidal swings, strong currents, and significant freshwater input. We investigated whether species richness and community composition differed across three habitat types (sand beaches, eelgrass beds, and rocky shorelines) and between high and low tides. Additionally, we tested whether replication of field samples and PCR reactions influenced either species richness or composition. We amplified a 12S mitochondrial locus in our samples and identified 188 fish amplicon sequence variants (ASVs), corresponding to 21 unique taxa, with approximately half of these resolved to single species. Species richness and composition inferred from eDNA differed substantially among habitats, with rock habitats containing fewer taxa and fewer overall detections than sand and eelgrass habitats. The effect of tide was more subtle and suggested a habitat-tide interaction, with differences in taxa between tides largely isolated to sand habitats. Power analyses indicated that additional field sampling is useful to detect subtle changes in species richness such as those due to tide. PCR replicates typically identified a small number of additional taxa. The most notable result from our study was that shore morphology appeared to substantially influence community structure. Rocky shorelines sloped quickly into deep water, while sand and eelgrass habitats descended much more gradually. We hypothesize that differences in taxa observed among habitats were largely due to lack of mixing between bottom and surface water, providing further evidence that eDNA transport is minimal and that many marine eDNA detections are derived from highly localized sampling locations. We suggest that future studies could explore the extent to which habitat and nearshore physical processes influence eDNA detections.

Las aves limícolas se destacan por sus largas migraciones y su dependencia de una amplia variedad de humedales anualmente. Su distribución en los hábitats de forrajeo está relacionada con la disponibilidad de presas. En este trabajo se caracterizó la dieta de tres especies del género Calidris, C. minutilla, C. pusilla y C. mauri en los humedales de Río Máximo (RM) y Tunas de Zaza (TZ) y es estudió su relación con la disponibilidad de presas. La dieta se caracterizó mediante análisis del contenido estomacal de individuos recolectados luego del horario pico de alimentación. La disponibilidad de presas se evaluó tomando 20 muestras de sedimento con una jeringuilla de 50 CC que fue enterrada a una profundidad de 10 mm. Posteriormente, las muestras fueron filtradas con un tamiz de 500 micras para facilitar la identificación. En RM el análisis de la dieta confirmó un elevado uso de larvas y pupas de dípteros por las tres especies. En TZ los dípteros fueron dominantes en la dieta de C. minutilla, pero las otras especies hicieron un uso más balanceado del alimento. La similitud entre los recursos disponibles en el sedimento y los encontrados en la dieta fue menor en TZ que en RM. Los tanaidáceos (Malacostraca) fueron la entidad más abundante en el sedimento de TZ, sin embargo, no se identificó en ningún estómago. De modo general, en RM las presas fueron consumidas de acuerdo con su disponibilidad, mientras que en TZ hubo mayor selectividad en el uso del alimento.

Cisco (Coregonus artedi) are threatened by climate change and lake eutrophication, and their oxythermal habitat can be assessed with TDO3, the water temperature at which dissolved oxygen equals 3 mg·L−1. We assessed the influence of TDO3 on cisco habitat use, genetic diversity, diets, and isotopic niche in 32 lakes ranging from oligotrophic to eutrophic. Results showed that as TDO3 increased, cisco were captured higher in the water column, in a narrower band, with higher minimum temperatures and lower minimum dissolved oxygen. TDO3 was also negatively related to cisco allelic richness and expected heterozygosity, likely driven by summer kill events. Moreover, TDO3 influenced the isotopic niche of cisco, as fish captured deeper were more depleted in δ13C and more enriched in δ15N compared to epilimnetic baselines. Lastly, cisco in high TDO3 lakes consumed more Daphnia, had fewer empty stomachs, and achieved larger body size. Our work identifies specific characteristics of cisco populations that respond to climate change and eutrophication effects and provides a framework for understanding responses of other cold-water species at the global scale.

Microbial communities associated with deep-sea animals are critical to the establishment of novel biological communities in unusual environments. Over the past few decades, rapid exploration of the deep sea has enabled the discovery of novel microbial communities, some of which form symbiotic relationships with animal hosts. Symbiosis in the deep sea changes host physiology, behavior, ecology, and evolution over time and space. Symbiont diversity within a host is often aligned with diverse metabolic pathways that broaden the environmental niche for the animal host. In this review, we focus on microbiomes and obligate symbionts found in different deep-sea habitats and how they facilitate survival of the organisms that live in these environments. In addition, we discuss factors that govern microbiome diversity, host specificity, and biogeography in the deep sea. Finally, we highlight the current limitations of microbiome research and draw a road map for future directions to advance our knowledge of microbiomes in the deep sea. Expected final online publication date for the Annual Review of Animal Biosciences, Volume 10 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Habitat suitability models have been used for decades to develop spatially explicit predictions of landscape capacity to support populations of target species. As high-resolution remote sensing data are increasingly included in habitat suitability models that inform spatial conservation and restoration decisions, it is essential to validate model predictions with independent, quantitative data collected over sustained time frames. Here, we used data collected from 12 reefs over a 14 yr sampling period to validate a recently developed physical habitat suitability model for intertidal oyster reefs in coastal Virginia, USA. The model used intertidal elevation, water residence time, and fetch to predict the likelihood of suitable conditions for eastern oysters Crassostrea virginica across a coastal landscape, and remotely sensed elevation was the most restrictive parameter in the model. Model validation revealed that adult oyster biomass was on average 1.5 times greater on oyster reefs located in predicted ‘suitable’ habitat relative to reefs located in predicted ‘less suitable’ habitat over the 14 yr sampling period. By validating this model with long-term population data, we highlight the importance of elevation as a driver of sustained intertidal oyster success. These findings extend the validation of habitat suitability models by quantitatively supporting the inclusion of remotely sensed data in habitat suitability models for intertidal species. Our results suggest that future oyster restoration and aquaculture projects could enhance oyster biomass by using habitat suitability models to select optimal site locations.

Coastal rivers and estuaries provide habitat and migratory corridors for freshwater estuarine-opportunists. We evaluated movement patterns of 61 blue catfish (Ictalurus furcatus) in the tidal York and Rappahannock rivers in Virginia, USA with acoustic telemetry from July 2015 to June 2016. To evaluate river-specific movements, we utilized a multistate Cormack–Jolly–Seber (CJS) model within a Bayesian framework to estimate probabilities of detection and transition (movement) among established salinity zones (i.e., tidal-fresh (0‰–0.5‰), oligohaline (>0.5‰–5‰), mesohaline (>5‰–18‰)). We considered flow as an environmental covariate. Despite high site fidelity in tidal-fresh zones, some individuals displayed movements into oligohaline and mesohaline habitats indicative of partial migration. Once downstream movement occurred, the probability of staying in the new salinity zone was higher than the probability of movements to other salinity zones. In the Rappahannock River only, movement upstream from mesohaline habitats was associated with below average flow. As flow increased, the probability of remaining in oligohaline and mesohaline zones increased. Our study shows blue catfish can move into downstream areas of tidal rivers with elevated salinities and that increased freshwater flow may allow them to remain in these habitats for extended durations.

Salmonids make flexible and adaptive trade-offs between foraging efficiency and predation risk that result in variable patterns of diel activity and habitat use. However, the following remains unclear: (1) how patterns differ among salmonid species; and (2) how this affects the interpretation of habitat suitability models that inform instream flow management. We combined snorkel observations with experimental additions of cover to investigate how predation risk, cover, and bioenergetics affect diel activity and habitat use patterns by sympatric rainbow trout (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus) in the Skagit River, British Columbia, Canada. Both species foraged primarily at dusk, supporting the well-described trade-off between foraging efficiency and predation risk. However, only rainbow trout responded to cover additions, suggesting that risk tolerance and the nature of foraging-predation risk trade-offs differ between species. Diel shifts in activity and habitat use also substantially altered predictions of habitat suitability models, with potentially large consequences for flow management.

Understanding the interacting role of climate and habitat in shaping wildlife population dynamics can help to reveal synergistic pathways that drive population resilience or decline across variable and changing environments. Moose (Alces alces) is a pan-boreal herbivore experiencing population declines across large portions of North America; however, the species has shown variable response to climate across its distribution. We investigated moose demographic response to climate and evaluated the interacting role of habitat across 36 years and along a biogeographic gradient in Ontario, Canada that has experienced decadal changes to climate and habitat quality. Moose density exhibited a nonlinear trend that initially increased and then decreased over the study timeframe and was negatively affected by regional and local patterns of winter severity and later frost onset. Recruitment exhibited a monotonic decline and was positively affected by spring heat and deciduous forest cover, while also exhibiting density-dependent effects. The negative response of moose density to winter severity was reduced in Wildlife Management Units (WMUs) with higher proportions of dense canopy cover, supporting expectations that this habitat type improves moose winter mobility and predator avoidance. The negative effect of later frost onset was greater in WMUs with more regenerating forest, and both variables are associated with higher exposure to parasites and predators. Further, density-dependent effects on recruitment were suppressed by warmer springs that support vegetation productivity and in WMUs with higher proportions of dense canopy cover that can provide concealment from predators. Our study illustrates the important role habitat conditions can have to mitigate, or exacerbate, climate-change effects for a wide-spread herbivore occupying variable environments by potentially altering pathways relevant to energetic balance, predation, and parasite transmission. In this system, moose occupying sparse or regenerating forests are more susceptible to adverse climatic effects and should be managed accordingly.

Sown wildflower areas are increasingly recommended as an agri-environmental intervention measure, but evidence for their success is limited to particular insect groups or hampered by the challenges of establishing seed mixes and maintaining flower abundance over time. We conducted a replicated experiment to establish wildflower areas to support insect pollinators in apple orchards. Over three years, and across 23 commercial UK orchards with and without sown wildflowers, we conducted 828 transect surveys across various non-crop habitats. We found that the abundance of flower-visiting solitary bees, bumblebees, honeybees, and beetles was increased in sown wildflower areas, compared with existing non-crop habitats in control orchards, from the second year following floral establishment. Abundance of hoverflies and other non-syrphid flies was increased in wildflower areas from the first year. Beyond the effect of wildflower areas, solitary bee abundance was also positively related to levels of floral cover in other local habitats within orchards, but neither local nor wider landscape-scale context affected abundance of other studied insect taxa within study orchards. There was a change in plant community composition on the sown wildflower areas between years, and in patterns of flowering within and between years, showing a succession from unsown weedy species towards a dominance of sown species over time. We discuss how the successful establishment of sown wildflower areas and delivery of benefits for different insect taxa relies on appropriate and reactive management practices as a key component of any such agri-environment scheme.

Coastal sharks can use shallow, nearshore habitats as nursery areas, which is a behaviour that may increase fitness. The ecological benefits of shark nursery areas are well studied; yet the physiological mechanisms that enable sharks to exploit coastal habitats, especially those that experience extreme and dynamic temperatures, remain understudied. We hypothesised that neonatal sharks are able to use thermally dynamic coastal habitats as nursery areas because temperature does not strongly affect their physiology. To test this hypothesis, we defined patterns of nursery area use and temperature-dependent physiological performance in 2 reef shark species. First, we determined whether 10 sites around the island of Moorea, French Polynesia, satisfied nursery area criteria for neonate populations of blacktip reef sharks Carcharhinus melanopterus and sicklefin lemon sharks Negaprion acutidens using 5 consecutive years of abundance surveys. We then quantified effects of thermal exposure in situ on growth in recaptured individuals and quantified the temperature dependence of metabolic rate ex situ using respirometry. We found several potential C. melanopterus nursery areas, but during different sampling years, and identified 1 N. acutidens nursery area that remained consistent during the entire 5 yr study. In support of our hypothesis, growth and metabolic performance were not strongly affected by temperature in either species. Thus, thermally insensitive physiological performance may be a trait that elasmobranchs exhibit in thermally variable coastal habitats, including shark nursery areas. Together, this approach demonstrates how physiological and ecological concepts complement each other to improve our understanding of nursery area use in coastal shark populations.