Tracking Marine Pollution Elliott, John E.; Elliott, Kyle H.
Science (American Association for the Advancement of Science),
05/2013, Letnik:
340, Številka:
6132
Journal Article
Recenzirano
Visit a beach almost anywhere and you will see plastic waste floating in the water and heaped above the tide lines. That debris is both a source and an overt signal of the even more pervasive ...contamination of marine biota by persistent chemicals. Present at ultra-trace levels but often highly toxic, chemical pollutants can be challenging to measure and understand. As the most problematic compounds biomagnify in food chains, sampling of marine top predators yields a global picture of ocean pollution.
Mercury (Hg) is a neurotoxin that can be particularly harmful to top predators because it biomagnifies through the food web. Due to variation in the food web structure, variation in Hg exposure in ...predators may represent variation in diet rather than Hg availability. We measured Hg in eggs from six seabird species (N = 537) over 47 years. In contrast to expectation, storm-petrels feeding partially on invertebrates had the highest Hg burden while herons feeding on large fish had the lowest Hg burden. A multiple regression showed that Hg correlated with δ34S (R 2 = 0.86) rather than trophic level (δ15N of “trophic” amino acids). Sulfate-rich environments (high δ34S) have sulfate-reducing bacteria that produce methylmercury. Variation in Hg within and among seabirds near the top of the food web was associated with variation in δ34S at the base of the food web more so than trophic position within the food web. Hg levels in seabirds only changed over time for those species where δ34S also varied in tandem; after accounting for diet (δ34S), there was no variation in Hg levels. Variation in Hg in seabirds across space and time was associated with the origin of sulfur in the diet.
Animals' abilities to fly long distances and dive to profound depths fascinate earthbound researchers. Due to the difficulty of making direct measurements during flying and diving, many researchers ...resort to modeling so as to estimate metabolic rate during each of those activities in the wild, but those models can be inaccurate. Fortunately, the miniaturization, customization and commercialization of biologgers has allowed researchers to increasingly follow animals on their journeys, unravel some of their mysteries and test the accuracy of biomechanical models. I provide a review of the measurement of flying and diving metabolic rate in the wild, paying particular attention to mass loss, doubly-labelled water, heart rate and accelerometry. Biologgers can impact animal behavior and influence the very measurements they are designed to make, and I provide seven guidelines for the ethical use of biologgers. If biologgers are properly applied, quantification of metabolic rate across a range of species could produce robust allometric relationships that could then be generally applied. As measuring flying and diving metabolic rate in captivity is difficult, and often not directly translatable to field conditions, I suggest that applying multiple techniques in the field to reinforce one another may be a viable alternative. The coupling of multi-sensor biologgers with biomechanical modeling promises to improve precision in the measurement of flying and diving metabolic rate in wild animals.
The role of the gut microbiome is increasingly being recognized by health scientists and veterinarians, yet its role in wild animals remains understudied. Variations in the gut microbiome could be ...the result of differential diets among individuals, such as variation between sexes, across seasons, or across reproductive stages. We evaluated the hypothesis that diet alters the avian gut microbiome using stable isotope analysis (SIA) and 16S rRNA gene sequencing. We present the first description of the thick-billed murre (Uria lomvia) fecal microbiome. The murre microbiome was dominated by bacteria from the genus Catellicoccus, ubiquitous in the guts of many seabirds. Microbiome variation was explained by murre diet in terms of proportion of littoral carbon, trophic position, and sulfur isotopes, especially for the classes Actinobacteria, Bacilli, Bacteroidia, Clostridia, Alphaproteobacteria, and Gammaproteobacteria. We also observed differences in the abundance of bacterial genera such as Catellicoccus and Cetobacterium between sexes and reproductive stages. These results are in accordance with behavioural observations of changes in diet between sexes and across the reproductive season. We concluded that the observed variation in the gut microbiome may be caused by individual prey specialization and may also be reinforced by sexual and reproductive stage differences in diet.
Stable isotope ratios are biogeochemical tracers that can be used to determine the source of nutrients and contaminants in avian eggs. However, the interpretation of stable carbon ratios in ...lipid-rich eggs is complicated because (13)C is depleted in lipids. Variation in (13)C abundance can therefore be obscured by variation in percent lipids. Past attempts to establish an algebraic equation to correct carbon isotope ratios for lipid content in eggs have been unsuccessful, possibly because they relied partly on data from coastal or migratory species that may obtain egg lipids from different habitats than egg protein. We measured carbon, nitrogen and sulphur stable isotope ratios in 175 eggs from eight species of aquatic birds. Carbon, nitrogen and sulphur isotopes were enriched in lipid-extracted egg samples compared with non extracted egg samples. A logarithmic equation using the C∶N ratio and carbon isotope ratio from the non extracted egg tissue calculated 90% of the lipid-extracted carbon isotope ratios within ±0.5‰. Calculating separate equations for eggs laid by species in different habitats (pelagic, offshore and terrestrial-influenced) improved the fit. A logarithmic equation, rather than a linear equation as often used for muscle, was necessary to accurately correct for lipid content because the relatively high lipid content of eggs compared with muscle meant that a linear relationship did not accurately approximate the relationship between percent lipids and the C∶N ratio. Because lipid extraction alters sulphur and nitrogen isotope ratios (and cannot be corrected algebraically), we suggest that isotopic measurement on bulk tissue followed by algebraic lipid normalization of carbon stable isotope ratio is often a good solution for homogenated eggs, at least when it is not possible to complete separate chemical analyses for each isotope.
Hutchison's niche theory suggests that coexisting competing species occupy non-overlapping hypervolumes, which are theoretical spaces encompassing more than three dimensions, within an n-dimensional ...space. The analysis of multiple stable isotopes can be used to test these ideas where each isotope can be considered a dimension of niche space. These hypervolumes may change over time in response to variation in behaviour or habitat, within or among species, consequently changing the niche space itself. Here, we use isotopic values of carbon and nitrogen of ten amino acids, as well as sulphur isotopic values, to produce multi-isotope models to examine niche segregation among an assemblage of five coexisting seabird species (ancient murrelet Synthliboramphus antiquus, double-crested cormorant Phalacrocorax auritus, Leach's storm-petrel Oceanodrama leucorhoa, rhinoceros auklet Cerorhinca monocerata, pelagic cormorant Phalacrocorax pelagicus) that inhabit coastal British Columbia. When only one or two isotope dimensions were considered, the five species overlapped considerably, but segregation increased in more dimensions, but often in complex ways. Thus, each of the five species occupied their own isotopic hypervolume (niche), but that became apparent only when factoring the increased information from sulphur and amino acid specific isotope values, rather than just relying on proxies of δ
N and δ
C alone. For cormorants, there was reduction of niche size for both species consistent with a decline in their dominant prey, Pacific herring Clupea pallasii, from 1970 to 2006. Consistent with niche theory, cormorant species showed segregation across time, with the double-crested demonstrating a marked change in diet in response to prey shifts in a higher dimensional space. In brief, incorporating multiple isotopes (sulfur, PC1 of δ
N baselines, PC2 of δ
N trophic position, PC1 and PC2 of δ
C) metrics allowed us to infer changes and differences in food web topology that were not apparent from classic carbon-nitrogen biplots.
Unmanned aerial vehicles (UAVs) provide an opportunity to rapidly census wildlife in remote areas while removing some of the hazards. However, wildlife may respond negatively to the UAVs, thereby ...skewing counts. We surveyed four species of Arctic cliff-nesting seabirds (glaucous gull Larus hyperboreus, Iceland gull Larus glaucoides, common murre Uria aalge and thick-billed murre Uria lomvia) using a UAV and compared censusing techniques to ground photography. An average of 8.5% of murres flew off in response to the UAV, but >99% of those birds were non-breeders. We were unable to detect any impact of the UAV on breeding success of murres, except at a site where aerial predators were abundant and several birds lost their eggs to predators following UAV flights. Furthermore, we found little evidence for habituation by murres to the UAV. Most gulls flew off in response to the UAV, but returned to the nest within five minutes. Counts of gull nests and adults were similar between UAV and ground photography, however the UAV detected up to 52.4% more chicks because chicks were camouflaged and invisible to ground observers. UAVs provide a less hazardous and potentially more accurate method for surveying wildlife. We provide some simple recommendations for their use.
Citizen science is filling important monitoring gaps and thus contributing to the conservation of rare or threatened animals. However, most researchers have used peer‐reviewed publications to ...evaluate citizen science contributions. We quantified a larger spectrum of citizen science's contributions to the monitoring of rare or threatened animals, including contributions to the peer‐reviewed publications, gray literature and to conservation measures (i.e., actions taken as a direct result of citizen science monitoring). We sought to provide broad information on how results of studies of citizen science monitoring is used. We also evaluated factors associated with success of citizen science projects. We conducted a web search to find citizen science projects focusing on rare and threatened species and surveyed citizen science project managers about their contributions and factors influencing their success. The number of projects increased rapidly after 2010. Almost one‐half of the citizen science projects produced at least 1 peer‐reviewed publication, 64% produced at least 1 gray literature publication, and 64% resulted in at least 1 conservation measure. Conservation measures covered a wide range of actions, including management and mitigation plans, modification of threat status, identification and establishment of protected areas, habitat restoration, control of invasive species, captive breeding programs, and awareness campaigns. Longevity, data quality, and collaboration type best explained quantities of all types of scientific contributions of citizen science. We found that citizen science contributed substantially to knowledge advancement and conservation, especially when programs were long term and had rigorous data collection and management standards, and multidisciplinary or transdisciplinary collaborations.
Resumen
La ciencia ciudadana contribuye a llenar vacíos en el monitoreo, lo que ayuda a la conservación de animales raros o amenazados. Sin embargo, la mayoría de los investigadores han usado publicaciones revisadas por pares para evaluar las contribuciones de la ciencia ciudadana. Cuantificamos un mayor espectro de las contribuciones de la ciencia ciudadana al monitoreo de animales raros y amenazados, incluyendo las contribuciones a la literatura gris, a las publicaciones revisada por pares y a las medidas de conservación (es decir, las acciones tomadas como resultado directo del monitoreo ciudadano). Buscamos proporcionar información generalizada sobre cómo los resultados de los estudios de monitoreo ciudadano es usado. También evaluamos los factores asociados con el éxito de los proyectos de ciencia ciudadana. Realizamos una búsqueda en línea para encontrar proyectos de ciencia ciudadana enfocados en especies raras o amenazadas y encuestamos a los gestores de estos proyectos sobre sus contribuciones y los factores que influyen sobre su éxito. El número de proyectos incrementó rápidamente a partir de 2010. De los proyectos de ciencia ciudadana, casi la mitad produjo al menos 1 publicación revisada por pares, el 64% produjo al menos una publicación en la literatura gris y el 64% derivó en al menos 1 medida de conservación. Las medidas de conservación abarcaron una gama extensa de acciones que incluyeron planes de gestión y mitigación, modificación del estado de amenaza, identificación y establecimiento de áreas protegidas, restauración del hábitat, control de especies invasoras, programas de reproducción en cautiverio y campañas de concientización. La longevidad, calidad de los datos y el tipo de colaboración explicaron de mejor manera las cantidades de todos los tipos de contribuciones científicas hechas por la ciencia ciudadana. Descubrimos que la ciencia ciudadana contribuyó sustancialmente al avance del conocimiento y la conservación, especialmente cuando los programas eran a largo plazo y contaban con estándares rigurosos de recolección y gestión de datos, y con colaboraciones multi o transdisciplinarias.
【摘要】
公民科学正在填补监测上的重大空缺, 从而为珍稀或受威胁动物的保护做出贡献。然而, 大多数研究者仅用同行评议文献来评估公民科学的贡献。我们量化了公民科学在监测珍稀或受威胁动物中更大范围的贡献, 包括对同行评议的灰色文献和保护措施(即作为公民科学监测的直接结果而采取的行动)的贡献, 从而为优化使用公民科学监测研究结果提供更多信息。我们还评估了影响公民科学项目成功的因素。本研究通过网络搜索寻找关注珍稀和受威胁物种的公民科学项目, 并访问了项目管理者, 以了解这些项目的贡献以及影响其成功的因素。我们发现, 公民科学项目的数量在2010年后迅速增加。几乎有一半的公民科学项目发表了至少一篇同行评议的文章, 64%的项目发表了至少一篇灰色文献, 还有64%的项目制定了至少一项保护措施。保护措施涵盖的行动十分广泛, 包括管理和减缓影响计划、改变威胁状态、识别和建立保护区、恢复生境、控制入侵物种、圈养繁殖计划和宣传活动。持续时间、数据质量和合作类型能最好地解释公民科学的各类科学贡献的数量。结果表明, 公民科学对知识进步和保护做出了巨大贡献, 特别是长期、有严格的数据收集与管理标准, 以及多学科或跨学科合作的项目。【翻译:胡怡思;审校:聂永刚】
Moult and migration are energetically demanding and require adequate nutrition. In some species, individuals may interrupt their fall migration to moult at discrete stopover locations outside of ...their breeding grounds (i.e., moult-migration) leading to competing nutritional demands for moult and migration. Here, we use DNA barcoding of fecal samples to compare the diet of moulting and actively migrating (post-moult) Swainson's Thrushes (Catharus ustulatus) and Tennessee Warblers (Leiothlypis peregrina) during their fall migration stopover at a large urban greenspace in Montreal, Canada. Diet differed according to moult status, species, and seasonality. Swainson's Thrushes had a broad diet with frequent detections of both insects and berry-producing shrubs; while detections in Tennessee Warblers' diets were mainly arthropods. For both species, more actively migrating individuals consumed fleshy-fruiting plants than moulting individuals. A higher proportion of moulting birds consumed arthropods compared to active migrants, due to either arthropod availability or a dietary preference for proteinaceous foods to grow feathers. Both species and moult classes consumed more native plants than non-native plants later in the season. We show the importance of managing urban greenspaces with native plants and diverse food sources that can provide for the different dietary needs of migratory birds.
Advances in operational simplicity and cost efficiency have promoted the rapid integration of unoccupied aerial vehicles (UAVs) into ecological research, yet UAVs often disturb wildlife, potentially ...biasing measurements. Studies of UAV effects on wildlife to date have focused on UAV trajectory or distance; however, UAV size and noise could be critical variables influencing wildlife responses.
Bats are cryptic aerial species that are difficult to survey using conventional means, and so we tested the effectiveness of drone‐based acoustic surveys for bats. We recorded the number of acoustic bat detections with and without a UAV present. We used three small, commercial rotary UAVs varying in size and noise intensity (249, 907, 1,380 g).
Larger and louder UAVs deterred significantly more bats, with no effect of take‐off distance on bat activity. The smallest and quietest UAV model had a similar change in bat activity compared with control measurements. Drone noise increased with drone size, but all drones emitted in a similar range of frequencies that overlapped with the larger bat species that were also those most impacted by the UAV. During the 5‐minute surveys, there was no evidence of bat habituation to UAVs although bats returned quickly once the UAV survey ended.
We urge wildlife researchers to consider drone size during wildlife surveys. Smaller and quieter models have negligible impacts on wildlife, eliminating the impact of drones on wildlife in some cases.
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