Variations in dietary patterns of living sloths revealed by finite element analysis of jaws.

Although extinct sloths exhibited a wide range of dietary habits, modes of locomotion, and occupied various niches across the Americas, modern sloths are considered quite similar in their habits. The dietary habits of living sloths can be directly observed in the wild, and understanding the mechanical behavior of their jaws during chewing through finite element analysis (FEA) provides a valuable validation tool for comparative analysis with their extinct counterparts. In this study, we used FEA to simulate the mechanical behavior of sloth mandibles under lateral mastication loads, using it as a proxy for oral processing. Our research focused on the six extant sloth species to better understand their diets and validate the use of FEA for studying their extinct relatives. We found that all living sloths have the predominancy of low-stress areas in their mandibles but with significant differences. Choloepus didactylus had larger high-stress areas, which could be linked to a reduced need for processing tougher foods as an opportunistic generalist. Bradypus variegatus and Choloepus hoffmanni are shown to be similar, displaying large low-stress areas, indicating greater oral processing capacity in a seasonal and more competitive environment. Bradypus torquatus, Bradypus pygmaeus, and Bradypus tridactylus exhibited intermediary processing patterns, which can be linked to a stable food supply in more stable environments and a reduced requirement for extensive oral processing capacity. This study sheds light on extant sloths' dietary adaptations and has implications for understanding the ecological roles and evolutionary history of their extinct counterparts.

Direct links between resource availability and activity budget better reveal ecological patterns of endangered Coimbra-Filho's titi monkey.

Many primatological studies do not assess direct indexes of food availability to make inferences about behavioral strategies. We related the diet and behavior of a group of Callicebus coimbrai in northeastern Brazil to fruit availability indexes and compared this pattern between seasons (direct and indirect assessment of food availability) to assess whether direct and indirect approaches detect similar ecological patterns. We monitored the study group for 33 months (5 days/month) via scan sampling. The monthly availability of fruits and new leaves was recorded in phenological transects. Fruit availability varied across years based on fruit prevalence, and timing and duration of the abundant seasons. We did not find evidence of a time-minimizing strategy, since C. coimbrai did not change its activity levels according to food availability. However, the negative relationship between foraging and fruit availability indicates that C. coimbrai can compensate for the lower fruit availability by increasing the search for alternative food sources. Monthly fruit consumption was positively correlated to fruit availability and negatively related to the consumption of other food items. However, the behavioral and feeding profiles did not vary between seasons and were not related to rainfall levels. Primate studies should directly relate behavioral and feeding profiles to fruit availability indices, thus avoiding using seasons as proxies of food availability.

A three-dimensional geometric morphometric analysis of the morphological transformation of Caiman lower jaw during post-hatching ontogeny.

Shape ontogenetic changes of the lower jaw in crocodylians are poorly understood. In order to answer some questions related to the inter- and intraspecific morphological variation of the mandible of two extant Caiman species, we performed a three-dimensional geometric morphometric approach. For this purpose, we used landmarks and semilandmarks on two ontogenetic mandibular series of 48 and 15 post-hatching specimens of C. yacare and C. latirostris, respectively. We have also examined the relationship between these anatomical transformations and ontogenetic shifts in diet. We performed a principal component analysis (PCA) for the two species, and regression and partial least squares (PLS) analyses for each species, separately. As a result, species were segregated along the PC1 with specimens of C. yacare showing more gracile mandibles, and specimens of C. latirostris more robust ones. The PC2 and regression analyses showed an age gradient and represented ontogenetic shape changes. Adult caiman mandibles are higher and wider than juvenile ones, and shape changes are more conspicuous in C. latirostris. The PLS analyses showed a significant relationship between shape and diet. Morphological changes of the PLS1 of block-1 match with those of the regression analysis for both species. We have detected morphological transformations in areas where the musculature in charge of mandibular movements is attached. Common morphological changes occurring during ontogeny seem to reflect the same mechanical properties required for crushing and killing in both species, driven by an ontogenetic shift in the diet from invertebrates to vertebrates. Additionally, interspecific differences were also found to be correlated to ontogenetic changes in diet and could be related to dissimilar feeding mechanical requirements (e.g., stiffness and toughness of the item consumed), and to different habitat preferences. Robust mandibles would be more suitable for shallow and fully vegetated environments, as it can be seen in C. latirostris, whereas slender jaws seem to be more suitable for more aquatic species such as C. yacare.

Capuchin monkey (Sapajus spp.) diet: current knowledge, gaps, and future directions.

Knowledge of the feeding habits of primate species is important for an understanding of their natural history and ecological interactions between their groups, and their interactions with their environments. Capuchin monkeys (Sapajus spp.) present significant diet flexibility and are a good model for investigating diet diversity between species. We undertook a systematic literature review of publications on the diet of free-living Sapajus spp. groups by using the Web of Science platform. We performed scientometric analyses of the objectives and hypotheses of the reviewed works, identified knowledge gaps, and evaluated the composition of each group's diet. Our results indicate geographic and taxonomic biases among the 59 published studies that we examined. The studies were focused on Sapajus nigritus, Sapajus libidinosus, and Sapajus apella, and undertaken in long-term study sites. Foraging and behavioral aspects of how food is processed were recurring themes. Capuchin monkeys increase their consumption of anthropogenic food according to its supply. Despite the similar objectives of these studies, standardized data collection protocols were not employed. Although Sapajus spp. are widely distributed and are used for cognitive studies, basic aspects of their natural history, such as their diet, remain unknown. We emphasize the importance of undertaking studies on this genus to fill the identified knowledge gaps, and propose that investigations should be carried out on the effects of dietary changes on individuals and groups. We stress that, as the Neotropical region is one of those most affected by anthropogenic impacts, opportunities to study these primates in their natural environments are diminishing daily.

Almost nothing is known about the tiger shark in South Atlantic waters.

The tiger shark (Galeocerdo cuvier) has been relatively well assessed concerning biology and ecology aspects in both Atlantic and Pacific North America and in Caribbean waters. The amount of data in these regions has led to the species protection under capture quotas and with the creation of sanctuaries. The reality in developing countries, however, is the exact opposite, with scarce information on the species in the southern hemisphere, namely South American and African waters. In these regions, protection measures are insufficient, and studies on tiger shark biology and ecology are scarce, significantly hindering conservation and management efforts. Thus, the aim of this study was to compile scientific literature on the tiger shark in the South Atlantic and discuss the impact of these data (or lack thereof) distributed within a total of ten research categories for guiding management plans. In total, 41 scientific publications on different G. cuvier biology and ecology aspects were obtained. The most studied topics were Feeding Ecology (n = 12), followed by Human Interactions (n = 8), and Movements and Migration (n = 7). Northeastern Brazil (Southwest Atlantic) was the most researched area, probably due to the higher coastal abundance of tiger sharks in this area, alongside a high number of recorded attacks, justifying funding for studies in the region. No studies carried out in other South American or African countries were found. It is important to mention that even though some research topics are relatively well covered, a severe knowledge gap is noted for risk assessments and fisheries management, with a proposition for the implementation of sanctuaries noted. This is, however, particularly worrisome, as the South Atlantic is mostly unexplored in this regard for tiger sharks. It is also important to note how different the attention given to this species is in the North Atlantic when compared to the South region. Lastly, we highlight that the existence of sub-populations, the lack of migratory corridors geographically connecting distinct areas used by the species, and the lack of fisheries statistics on tiger shark landings, all increase the vulnerability of this species in the South Atlantic.

Plastic ingestion by carnivore fish in a neotropical floodplain: seasonal and interspecific variations.

Some studies have shown that freshwater ecosystems are polluted in a similar proportion to marine ecosystems; however, there are many gaps to be filled in this topic. Here, we investigated whether plastics were consumed by carnivore fishes in a Neotropical floodplain and whether it was connected to seasonality (dry and wet seasons). We also evaluated the association between each type of plastic and the fish species. We analyzed the gastrointestinal contents of 23 species and assessed the occurrence and number of plastic particles. Plastics were obtained through chemical digestion and the spectrum of each sample, using a FT-IR imaging microscope. We performed a correspondence analysis (CA) with plastic data to assess the relationship between each type of plastic and the fish species. We also performed linear regression models to assess the relationships of occurrence and number of plastics ingested with seasonality. Nine species had plastics in their gastrointestinal contents, and they were identified as polyvinyl alcohol (PVA), polyamide (PA), polyethylene (PE), polystyrene (PS), and polypropylene (PP). The number of plastics had a positive relationship with the wet season, while the occurrence did not show a significant relationship with any season. These results are particularly important when considering the socioeconomic relevance and the ecological importance of this trophic guild.

Comparative trophic ecology of two sympatric guitarfishes Pseudobatos (Chondrichthyes, Rhinobatidae) from Southeast Brazil, southwestern Atlantic.

The present study compares the trophic ecology of two guitarfishes (Pseudobatos percellens and Pseudobatos horkelii) from the continental shelf of the São Paulo State, Brazil, caught by the bottom pair trawls between 2007 and 2009. These two sympatric species are under different threat categories, "Vulnerable" and "Critically Endangered," respectively, according to Brazilian agencies. Thus, any study considering trophic ecology parameters is pivotal in understanding the trophic ecology role of such species in the ecosystem. The authors analysed 500 stomachs of P. percellens and 108 of P. horkelii, quantifying with dietary indexes: numerical (%N), gravimetric (%W), frequency of occurrence (%FO) and the prey-specific index of relative importance (%PSIRI). For P. percellens and P. horkelii, 26 and 14 different prey items were found, respectively. Crustacea and Teleostei were the most important prey items for both species, indicating a specialist feeding behaviour due to their low niche amplitude. The results provide evidence related to ontogenetic dietary shift in P. percellens and individual-level diet specialization in both species. These two benthic-demersal elasmobranchs are important mesopredators (3,7 for P. percellens, and 3,5 for P. horkelii) in the study area, with high trophic-level values.

Trophic ecology of three stingrays (Myliobatoidei: Dasyatidae) off the Brazilian north-eastern coast: Habitat use and resource partitioning.

Understanding the ecological role of species with overlapping distributions is central to inform ecosystem management. Here we describe the diet, trophic level and habitat use of three sympatric stingrays, Hypanus guttatus, H. marianae and H. berthalutzae, through combined stomach content and stable isotope (δ13 C and δ15 N) analyses. Our integrated approach revealed that H. guttatus is a mesopredator that feeds on a diverse diet of benthic and epibenthic marine and estuarine organisms, principally bivalve molluscs, Alpheus shrimp and teleost fishes. Isotopic data supported movement of this species between marine and estuarine environments. H. berthalutzae is also a marine generalist feeder, but feeds primarily on teleost fishes and cephalopods, and consequently occupies a higher trophic level. In contrast, H. marianae is a mesopredator specialized on shrimps and polychaetas occurring only in the marine environment and occupying a low niche breadth. While niche overlap occurred, the three stingrays utilized the same prey resources at different rates and occupied distinct trophic niches, potentially limiting competition for resources and promoting coexistence. These combined data demonstrate that these three mesopredators perform different ecological roles in the ecosystems they occupy, limiting functional redundancy.

Tree Species and Morphology of Holes Caused by Black-Tufted Marmosets to Obtain Exudates: Some Implications for the Exudativory.

Knowledge of the pattern of exploitation of trees can help us understand the relationship between marmosets and plants, especially in declining forests, such as those in the Brazilian Cerrado. Black-tufted marmosets (Callithrix penicillata) regularly exploit exudates by gouging the bark of trees with their specialized teeth. Determining preferred tree species to exploit exudates is important for forest management aimed at maintaining an essential food source for urban marmosets. We characterized the tree species, dendrometry, and the characteristics of the holes made by marmosets to obtain exudates. Based on these data, we proposed a gouging effort index (Chiseling Suitability Index for Marmosets, ChiSI). We identified 16 species belonging to 10 families of trees with gouging marks made by marmosets. Eleven new tree species used by black-tufted marmosets for exudates were identified in urban forests in the Cerrado. Exudate exploration was predominantly of medium intensity, with round holes concentrated in the canopy. The species Tapirira guianensis and Croton urucarana were preferred. The ChiSI was characterized by a narrow range for both T. guianensis and C. urucarana. Despite the flexibility of obtaining exudates, the black-tufted marmosets concentrate their exploitation to only a few tree species. The T. guianensis and C. urucarana tree species should be considered the most important species for management plans and the preservation of black-tufted marmosets that live in urban forests in the Cerrado.

The impacts of seasonal variation and climate on food utilization in a population of critically endangered cotton-top tamarins (Saguinus oedipus) in Colombia: A 22-year longitudinal study.

To examine how precipitation patterns and climate change impact feeding choices made by a population of critically endangered cotton-top tamarins (Saguinus oedipus), we examined 22 years of feeding data (1999-2020) from 21 groups collected at Parque Natural Regional Bosque Seco El Ceibal Mono Tití in Santa Catalina, Colombia. We describe the diet and examine the role of seasonal rainfall and annual variation in rainfall on diet. Rainfall is highly seasonal (mean annual rainfall 1562 mm [range 940-2680 mm]) with a dry, early rainy, and late rainy season in each year. Over 80 species of plants formed part of the fruit, nectar, and exudate components of the diet. Fruits, although available year-round, were more commonly available and consumed during the late rainy seasons (August-November). Exudates were consumed more frequently in the dry season (December-March) and invertebrate consumption was stable across the year. Nectar feeding from a single species (Combretum fruticosum) peaked in November. Rainfall varied over the years, with 13 years exceeding the 99% confidence intervals for mean rainfall. Ten of these extreme years (both drought and extremely wet) occurred in the last 11 years. Fruit consumption did not vary between extreme and average years, but cotton-top tamarins consumed more invertebrates and exudates in wet years. Presently, cotton-top tamarins appear to be able to cope with these extreme variations in rainfall due to their highly varied diet. However, the forests that these primates depend upon for survival are threatened by human exploitation making it critically important to maintain a generalist feeding strategy for survival as many fruiting trees that compose a large proportion of the diet are removed. As conservation efforts continue, plant species consumed by cotton-top tamarins provide useful data when selecting species for habitat restoration programs.

Phenotypic variation among silverside populations (Atherinopsidae: Atherinella brasiliensis) from distinct environments in Northeastern Brazil.

The successful adaptation of populations to a wide range of environments is a central topic in ecology. Based on the assumption that body shape may affect survival, we evaluated to what extent biotic and abiotic factors are capable of inducing morphological changes in Brazilian silverside populations (Atherinella brasiliensis). To reach this goal, we compared 18 morphological traits of specimens from five ecosystems representing three types of environment (estuary, coastal lagoon, reservoir). Populations from estuaries displayed greater anal fin area and greater caudal fin aspect ratio and area. Populations from coastal lagoons had more compressed bodies, larger heads, and slightly broader caudal peduncles. The fish from estuaries and coastal lagoons had longer caudal peduncles, larger pelvic fins and larger eye area. Population from reservoir had more depressed bodies and greater oral protrusion. Food availability explained 31% of the observed ecomorphological patterns. Overall, the morphology of the respective populations was consistent with each type of environment, making it possible to associate phenotypic variation with habitat and feeding patterns, although abiotic factors were more significant than biotic factors. In conclusion, landlocked populations of A. brasiliensis are sustainable and add to current knowledge of phenotypical variability in a species widely distributed along the Western Atlantic coast.

The ingestion of a large prey facilitating the capture of the predator: a study case in Micrurus corallinus (Serpentes Elapidae)

We report a case of predation of a large specimen of the Dipsas neuwiedi by a Micrurus corallinus, in the state of Santa Catarina, Brazil. The ingestion reported here is one of the greatest prey / predator ratios registered for genus Micrurus in nature. In this predation event, the ingestion of a large prey limited the M. corallinus locomotion, which did not offer resistance and was not able to move efficiently during the capture.

Chemical defense in developmental stages and adult of the sea star Echinaster (Othilia) brasiliensis.

To date, evidence regarding the performance of secondary metabolites from larval stages of sea stars as an anti-predation defense relates only to a few species/specimens from a few geographic ranges. Unfortunately, this hinders a comprehensive global understanding of this inter-specific predator-prey interaction. Here, we present laboratory experimental evidence of chemical defense action in the early developmental stages and adults of the sea star Echinaster (Othilia) brasiliensis from Brazil against sympatric and allopatric invertebrate consumers. Blastulae, early and late brachiolarias of E. (O.) brasiliensis were not consumed by the sympatric and allopatric crabs Mithraculus forceps. Blastulae were also avoided by the sympatric and allopatric individuals of the anemone Anemonia sargassensis, but not the larval stages. Extracts from embryos (blastula) and brachiolarias of E. (O.) brasiliensis from one sampled population (João Fernandes beach) significantly inhibited the consumption by sympatric M. forceps, but not by allopatric crabs and A. sargassensi anemone. In this same site, extracts from adults E. (O.) brasiliensis significantly inhibited the consumption by sympatric and allopatric specimens of the crab in a range of concentrations. Whereas equivalent extract concentrations of E. (O.) brasiliensis from other population (Itaipu beach)inhibited the predation by allopatric M. forceps, while sympatric individuals of this crab avoided the only the higher level tested. Then, early stages and adult specimens of E. (O.) brasiliensis can be chemically defended against consumers, but this action is quite variable, depending on the type (anemone or crab) and the origin of the consumer (sympatric or allopatric).

Anthropogenic edges impact howler monkey (Alouatta palliata) feeding behaviour in a Costa Rican rainforest.

Anthropogenic forest fragmentation impacts many aspects of animal behaviour, including feeding ecology. With forests increasingly fragmented in tropical regions due to human development, the proportion of forest edge (≤ 100 m from clear-cut regions) is higher relative to forest interior. Forest edges differ in vegetation from interior, making it important to better understand how anthropogenic edges impact the feeding behaviour of primates such as mantled howler monkeys (Alouatta palliata). We predicted that howler monkeys would feed on higher-quality plant resources, from a larger number of tree families, and from larger trees in forest interior compared to anthropogenic forest edge. We surveyed howler monkey feeding behaviour across forest zones in a fragmented rainforest in Costa Rica, La Suerte Biological Research Station. We observed individual monkeys for 30-minute periods, collecting data on their feeding behaviour and tree use at 2-minute intervals. We measured feeding trees and recorded the plant parts and taxonomy of resources consumed. Monkeys consumed more leaves and fewer stems and fed from a smaller number of tree families in the forest interior, while they consumed fewer leaves and more stems and fed from a larger number of tree families in the forest edge. Monkeys also fed from larger, taller trees in the forest interior than the edge. The differences in howler monkey feeding behaviour between forest zones attest to the impact of human disturbance on howler monkey feeding ecology.

Seasonal variation of Hedruris dratini (Nematoda) parasitizing Hydromedusa tectifera (Chelidae), with focus on host's torpor state.

BACKGROUND: The aim of this study was to analyze the seasonal distribution of the nematode Hedruris dratini parasitizing the South American Snake-necked turtle Hydromedusa tectifera and the amphipod Hyalella spp. in an urban stream. We focused on understand which strategies parasite population displays to get through the host's hibernation period. RESULTS: The highest prevalence and abundance of H. dratini were found in summer. The parasitic load was lower in winter, however there were no significant differences when it was compared with autumn and spring. Generalized linear model identified the temperature as a determining factor for the presence of parasites in turtles. CONCLUSIONS: Our results indicate that, beside turtles enter in a diapause state, the life cycle of H. dratini never stop throughout the year, being a continuous transmission between both the intermediate and final host throughout the year. Turtles feed and become infected with parasite larvae even in winter although with a lower ingestion rate.

Lone males: Solitary and group-living male howler monkey (Alouatta palliata) behavioral ecology in a Costa Rican rainforest.

OBJECTIVES: Many group-living primate species have evolved the capacity for some individuals to live alone for part of their lives, but this solitary life stage has rarely been the subject of focused research. The mantled howler monkey (Alouatta palliata) is a social primate species with bisexual dispersal that lives in mixed-sex groups with low male-to-female sex ratios. Consequently, males often spend a long period of their lives as solitary individuals. This study compares the tree use, feeding, and long-distance vocalization behavior of solitary and group-living mantled howler monkey males living within a fragmented rainforest in Costa Rica, La Suerte Biological Research Station. Based on differences in competitive ability between solitary and group-living males, we predicted that lone males would be found in significantly smaller feeding and resting trees, consume more low-quality foods, and produce shorter howling bouts made at lower rates than group-living males. MATERIALS AND METHODS: We collected data on tree use and feeding during 30-min focal samples on male focal animals, recording data at 2-min intervals. We measured the trees in which the monkeys fed and rested for two or more intervals, and recorded the plant parts consumed. We recorded howling behavior using all-occurrences sampling. RESULTS: Lone males used significantly smaller feeding and resting trees, consumed more low-quality foods, and howled at lower rates but had longer howling bouts triggered by anthropogenic noise more than group-living males. DISCUSSION: Our results demonstrate that lone males differ in their behavioral ecology compared to group-living males, thus improving understanding of the solitary male life stage in primates.

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.(AU)

Kajikia audax, Thunnus albacares, Katsuwonus pelamis e Auxis spp. ocupam posições tróficas intermedias e/ou elevadas nas cadeias alimentares. Estas espécies representam um importante recurso pesqueiro no Ecuador. Apesar da sua importância económica e ecológica, estudos nestas espécies pelágicas no Ecuador são raras. Este estudo usa isótopos estáveis para avaliar o seu nível trófico de modo a determinar a contribuição das suas presas para os tecidos destes predadores. Dados dos isótopos foram usados para testar a hipótese de que estas espécies de peixes pelágicos possuem valores mais elevados de δ15N do que daqueles das presas consumidas, e que não existe uma sobreposição entre os valores de δ13C e δ15N. Resultados mostram que valores mais elevados de δ15N para K. audax, seguidos por T. albacares, Auxis spp. e K. pelamis, indicam que a posição mais elevada na cadeia alimentar é ocupada por K. audax. Elipses Bayesianas de isótopos estáveis demonstram que, a uma escala de longo-termo, estas espécies de peixes não competem pelos recursos. Adicionalmente, os valores de δ15N são diferentes entre espécies de peixe estudadas e estes valores decrescem com a diminuição do tamanho do predador.(AU)

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.(AU)

Kajikia audax, Thunnus albacares, Katsuwonus pelamis e Auxis spp. ocupam posições tróficas intermedias e/ou elevadas nas cadeias alimentares. Estas espécies representam um importante recurso pesqueiro no Ecuador. Apesar da sua importância económica e ecológica, estudos nestas espécies pelágicas no Ecuador são raras. Este estudo usa isótopos estáveis para avaliar o seu nível trófico de modo a determinar a contribuição das suas presas para os tecidos destes predadores. Dados dos isótopos foram usados para testar a hipótese de que estas espécies de peixes pelágicos possuem valores mais elevados de δ15N do que daqueles das presas consumidas, e que não existe uma sobreposição entre os valores de δ13C e δ15N. Resultados mostram que valores mais elevados de δ15N para K. audax, seguidos por T. albacares, Auxis spp. e K. pelamis, indicam que a posição mais elevada na cadeia alimentar é ocupada por K. audax. Elipses Bayesianas de isótopos estáveis demonstram que, a uma escala de longo-termo, estas espécies de peixes não competem pelos recursos. Adicionalmente, os valores de δ15N são diferentes entre espécies de peixe estudadas e estes valores decrescem com a diminuição do tamanho do predador.(AU)

Integrating Gut Bacterial Diversity and Captive Husbandry to Optimize Vulture Conservation.

Endangered species recovery plans often include captive breeding and reintroduction, but success remains rare. Critical for effective recovery is an assessment of captivity-induced changes in adaptive traits of reintroduction candidates. The gut microbiota is one such trait and is particularly important for scavengers exposed to carcass microbiomes. We investigated husbandry-associated differences in the gut microbiota of two Old World vulture species using 16S RNA gene amplicon sequencing. Increased abundance of Actinobacteria occurred when vultures were fed quail but not rat or chicken. Conversely, diet preparation (sanitization) had no effect, although bacterial diversity differed significantly between vulture species, likely reflective of evolved feeding ecologies. Whilst the relative lack of influence of a sanitized diet is encouraging, changes in bacterial abundance associated with the type of prey occurred, representing a dietary influence on host-microbiome condition warranting consideration in ex situ species recovery plans. Incorporation of microbiome research in endangered species management, therefore, provides an opportunity to refine conservation practice.

Ecology of microplastics contamination within food webs of estuarine and coastal ecosystems.

The aim was to describe a methodology developed to study the relationship among the spatio-temporal patterns of habitat utilization, feeding ecology and microplastics (MPs) contamination across the different ontogenetic phases of fishes belonging to different trophic levels and living along the riverine-estuarine-coastal food web. The Goiana Estuary's water column was examined for the seasonal and spatial variation of MPs and their quantification relative to zooplankton, demersal fish species contamination following the same sampling design. The density of MPs in the water column determines their bioavailability. Interest in studies on MPs distribution in relation to spatial and temporal variation of environmental factors and fauna are increasing in quantity and quality. If the ecological strategies presented in this study were replicated in other estuary, comparisons could be made in order to describe how ecosystems work. Standard protocols for sampling, extraction, enumeration and classification of MPs and others pollutant ingested by fishes have been developed and are presented here to encourage comparisons. Standardized and comparable sampling designs and laboratory procedures are an important strategy in order to devise and transfer managerial solutions among different sites and comparisons along time when studying the same environment.