共查询到20条相似文献，搜索用时 15 毫秒
1.
Robin W. Baird Daniel L. Webster † Sabre D. Mahaffy ‡ Daniel J. McSweeney § Gregory S. Schorr ¶ Allan D. Ligon &#; 《Marine Mammal Science》2008,24(3):535-553
In the Pacific, rough-toothed dolphins ( Steno bredanensis ) are typically found in the open ocean and in deep waters around oceanic islands. We examined habitat use, site fidelity, movements, and association patterns of this species in the main Hawaiian Islands. Sighting rates were highest in depths >1,500 m. There were frequent within- and between-year resightings off the island of Hawai'i, indicating a small population size with high site fidelity. Resighting rates were lower off Kaua'i/Ni'ihau, indicating a larger population size, but with some site fidelity. Two individuals were documented moving from Kaua'i to Hawai'i, a distance of 480 km, but were not seen to associate with dolphins off Hawai'i. Observed movements were consistent with at most 2% dispersal per year between these two areas. Differences in group sizes, habitat use, and behavior imply that movements among the islands may be limited. Little is known about the diet of rough-toothed dolphins in Hawai'i, but they are thought to feed primarily on near-surface species. High fidelity to deep-water areas off the island of Hawai'i likely reflects an increase in the predictability of prey associated with upwelling due to the island mass effect, wind stress curl and cyclonic eddies that form off the island. 相似文献
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Observational studies describe rough-toothed dolphins (Steno bredanensis) actively foraging during the day on epipelagic species. Using data from depth-transmitting satellite tags deployed on nine individuals off Kauaʻi, we investigated diving behavior and the effects of lunar phase and solar light levels on vertical movements. Overall, tagged rough-toothed dolphins primarily used near-surface waters, spending between 83.6% and 93.7% of their time in the top 30 m of the water column. When diving, grand mean, median, and maximum dive depths were 76.9 m, 67.5 m, and 399.5 m, although individuals were in water with depths from approximately 700–1,450 m. Dive rates varied by time of day, being lowest during the day and at dawn and highest at dusk and night. Dives were deepest (M = 133.7 m, SD = 52.6 m, median = 106.5 m) and longest (M = 4.0 min, SD = 0.4 min, median = 4.0 min) at dusk, suggesting dolphins were taking advantage of prey rising to the surface in response to reduced light levels. Lunar phase indirectly affected diving, with deeper and longer dives occurring with increasing illumination. The variations in dive behavior across solar and lunar cycles indicate diving patterns shift based on the distribution of prey. 相似文献
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K. BITENCOURTH C. M. VOLOCH N. M. SERRA‐FREIRE E. MACHADO‐FERREIRA M. AMORIM G. S. GAZÊTA 《Medical and veterinary entomology》2016,30(3):342-350
Amblyomma sculptum (Ixodida: Ixodidae) Berlese, 1888, a member of the Amblyomma cajennense complex, is the major vector of Brazilian spotted fever (BSF) in southeastern Brazil. In this study, the genetic diversity of A. sculptum populations in the state of Rio de Janeiro (RJ), Brazil, was investigated because genetic variability in tick populations may be related to vector competence. Samples of A. sculptum from 19 municipalities in 7 regions of RJ were subjected to DNA extraction, amplification and sequencing of D‐loop, cytochrome oxidase II and 12S rDNA mitochondrial genes. These sequences were used to map the genetic diversity of this tick. Amblyomma sculptum populations are genetically diverse in RJ, especially in the South Centre and Highland regions. Few unique haplotypes were observed in all populations, and the majority of genetic variation found was among ticks within each population. Phylogenetic reconstruction reinforced the assumption that all the haplotypes identified in RJ belong to A. sculptum. However, some RJ haplotypes are closer to A. sculptum from Argentina than to A. sculptum from elsewhere in Brazil. In RJ, A. sculptum has high genetic diversity, although little genetic differentiation. Observations also indicated a high level of gene flow among the studied populations and no evidence of population structure according to region in RJ. 相似文献
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An unusual species of Leptophlebiidae is described based on males, females, and nymphs from Rio de Janeiro State, Brazil. As a consequence of its distinct characteristics on all stages, a new genus is established. The new genus can be distinguished from other South American Leptophlebiid genera mostly by: Adults: vein MA of fore wings asymmetrical; hind wings with costal projection well developed, Sc ending at cross vein near costal projection; tarsal claws dissimilar, one blunt other acute; projections of styliger plate forming two well developed lobes with rounded apex, ventrally obstructing view of the penes; penes fused on basal half, each lobe with a ventral furrow and a long and slender spine directed anteriorly. Nymphs: Head prognathous, wider than labrum; labrum with prominent median emargination, with three subtle crenulations; body flattened; hind wings pads present; tarsal claws with over 20 denticles, subapical denticle much larger than remaining denticles; gills long and narrow, present on abdominal segments I-VII; posterolateral projections present on abdominal segments VIII-IX. Phylogenetic analyses conducted based on a previously published data matrix that included other South America leptophlebiid genera placed Poranga nessimiani gen. nov. et sp. nov. as sister to Bessierus + Perissophlebioides. In most analyses this clade was recovered within the Farrodes complex. Nymphs of the new taxa are particularly similar to Bessierus, whereas adults share the very acute costal projection on hind wings seen in non-dipterous members of the Farrodes complex. 相似文献
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R Docampo F S Cruz A Boveris R P Muniz D M Esquivel 《Archives of biochemistry and biophysics》1978,186(2):292-297
β-Lapachone, an antimicrobial agent, was reduced by Trypanosoma cruzi epimastigotes to a semiquinone radical. It markedly increased the generation of superoxide anion and hydrogen peroxide in intact cells. Using NADH as electron donor, β-lapachone also increased significantly the rate of H2O2 generation in epimastigote homogenates. Incubation of epimastigotes with β-lapachone stimulated lipid peroxidation. 相似文献
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Abstract: Differences in spatial distribution and abundance of bud galls caused by eriophyoid mites (Acari: Eriophyoidea) among Carpinus tschonoskii (Betulaceae) were studied. This mite preferentially induces galls on terminal buds. Four factors influencing gall abundance were examined: host tree size, host tree's reproductive status, altitude and study site. As tree size increased, the number of galls increased to an apparent asymptote. This result suggests that tree size-dependent characteristics such as number of terminal buds, temporal pattern of shoot elongation and reproductive status influence gall abundance. 相似文献
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Elizabeth A. Becker James V. Carretta Karin A. Forney Jay Barlow Stephanie Brodie Ryan Hoopes Michael G. Jacox Sara M. Maxwell Jessica V. Redfern Nicholas B. Sisson Heather Welch Elliott L. Hazen 《Ecology and evolution》2020,10(12):5759-5784
Species distribution models (SDMs) are important management tools for highly mobile marine species because they provide spatially and temporally explicit information on animal distribution. Two prevalent modeling frameworks used to develop SDMs for marine species are generalized additive models (GAMs) and boosted regression trees (BRTs), but comparative studies have rarely been conducted; most rely on presence‐only data; and few have explored how features such as species distribution characteristics affect model performance. Since the majority of marine species BRTs have been used to predict habitat suitability, we first compared BRTs to GAMs that used presence/absence as the response variable. We then compared results from these habitat suitability models to GAMs that predict species density (animals per km2) because density models built with a subset of the data used here have previously received extensive validation. We compared both the explanatory power (i.e., model goodness of fit) and predictive power (i.e., performance on a novel dataset) of the GAMs and BRTs for a taxonomically diverse suite of cetacean species using a robust set of systematic survey data (1991–2014) within the California Current Ecosystem. Both BRTs and GAMs were successful at describing overall distribution patterns throughout the study area for the majority of species considered, but when predicting on novel data, the density GAMs exhibited substantially greater predictive power than both the presence/absence GAMs and BRTs, likely due to both the different response variables and fitting algorithms. Our results provide an improved understanding of some of the strengths and limitations of models developed using these two methods. These results can be used by modelers developing SDMs and resource managers tasked with the spatial management of marine species to determine the best modeling technique for their question of interest. 相似文献
11.
João Marcelo Alvarenga Braga 《Kew Bulletin》2008,63(2):309-314
Summary
Calathea dryadica and Calathea reginae are described, circumscribed and illustrated. These new species are probably endemic to the Atlantic Forest of Rio de Janeiro
State in Southeast Brazil and are considered critically endangered because of the restricted geographic area of occurrence,
sometimes enclosed by densely urbanised areas. 相似文献
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红外相机技术的发展促进了对东北虎(Panthera tigris altaica)、东北豹(Panthera pardus orientalis)及其猎物种群的研究。本研究以珲春保护区春化和马滴达两个区域的监测结果为例, 介绍利用该技术对我国长白山区东北虎、东北豹及其猎物的种群评估方法, 包括监测位点的选择、相机的架设方式及参数设置、数据筛选、东北虎和东北豹体侧花纹个体识别方法、物种相对丰富度的计算以及捕食者与猎物丰富度关系模型的构建。最后就东北虎、东北豹体侧花纹个体识别技术的适用性、红外相机监测与传统调查方法的差异, 相机监测的误差进行了讨论。研究表明, 利用红外相机技术进行密度预测以及东北虎、东北豹个体自动识别技术还需继续完善。1对/25 km2的相机架设密度基本上满足对于珲春保护区春化至马滴达区域虎豹的监测强度要求, 但对于有蹄类则需要另外的监测方案。 相似文献
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Achmad Sahri Mochamad I. H. Putra Putu L. K. Mustika Albertinka J. Murk 《Journal of Biogeography》2020,47(10):2102-2116
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Alcantarea turgida andA. tortuosa are described and illustrated as new species from southeastern Brazil. The relationships ofA. turgida withA. extensa and withA. vinicolor and ofA. tortuosa withA. farneyi and withA. benzingii are discussed. 相似文献
15.
Moritz Mercker Nele Markones Kai Borkenhagen Henriette Schwemmer Johannes Wahl Stefan Garthe 《The Journal of wildlife management》2021,85(4):751-771
Generating trend and population estimates from bird count data is challenging and a variety of factors have to be taken into account. We present an integrative statistical approach for estimating population numbers and trends for seabirds at sea. The method allows for the integration of bird-count data from different sources and sampling schemes: offshore observer-based line transect and digital strip transect surveys and land-based point counts; the estimation of log-linear and highly nonlinear trends; the prediction of population numbers for predefined sub-areas, years, or seasons; and investigations of the effects of various environmental and detection-related covariates on bird count numbers. We applied the approach to count data for great black-backed gulls (Larus marinus) in the German part of the North Sea and Baltic Sea from 1990–2016. Count data were collected by observer-based offshore ship and aerial surveys, offshore digital aerial surveys, and point counts from the shore. The detectability of great black-backed gulls was affected by the sea state (the condition of the sea surface, characterized by wave height, wave form, foam, and spray) and survey method. Digital and observer-based aerial surveys detected only 59–77% of the abundance recorded by ship-based surveys. Great black-backed gulls are mainly present in German waters in winter, when they account for 3–4% of the European population. Their core distributional areas are mainly in deeper offshore waters where they are relatively dispersed, with several concentrations probably connected to fishing activity. Great black-backed gulls have undergone substantial declines, with the most pronounced decreases of >90% in the offshore waters of the German part of the North Sea. Breeding numbers at important European breeding sites do not show similar declines, suggesting that the trends observed in the sea areas might indicate a shift in the distribution or habitat use and a decreasing importance of marine areas for European great black-backed gulls. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society. 相似文献
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This study estimates the population size of Indo-Pacific bottlenose dolphins ( Tursiops aduncus ) in the Algoa Bay region on the Eastern Cape coast of South Africa. Mark-recapture analyses were performed on photo-identification data collected on 54 occasions during a 3-yr-study period. Using a photographic data set of over 10,000 ID-images, 1,569 individuals were identified, 131 of which were photographed on more than one occasion. Using the POPAN formulation in the software program MARK, a total population of approximately 28,482 individuals (95% CI = 16,220–40,744; CV = 0.220), was estimated (estimate corrected for the proportion of distinctive individuals in the population). This is the largest population estimate to date for this species along the South African coast, suggesting that the bottlenose dolphins inhabiting the Algoa Bay region represent part of a substantially larger population that ranges along a considerable length of the South African coast. 相似文献
17.
Andrés L. Rodriguez-Cordero;Sergio A. Balaguera-Reina;Brandon A. Gross;Margaret Munn;Llewellyn D. Densmore; 《Ecology and evolution》2024,14(9):e70235
Species–environment relationships have been extensively explored through species distribution models (SDM) and species abundance models (SAM), which have become key components to understand the spatial ecology and population dynamics directed at biodiversity conservation. Nonetheless, within the internal structure of species' ranges, habitat suitability and species abundance do not always show similar patterns, and using information derived from either SDM or SAM could be incomplete and mislead conservation efforts. We gauged support for the abundance–suitability relationship and used the combined information to prioritize the conservation of South American dwarf caimans (Paleosuchus palpebrosus and P. trigonatus). We used 7 environmental predictor sets (surface water, human impact, topography, precipitation, temperature, dynamic habitat indices, soil temperature), 2 regressions methods (Generalized Linear Models—GLM, Generalized Additive Models—GAM), and 4 parametric distributions (Binomial, Poisson, Negative binomial, Gamma) to develop distribution and abundance models. We used the best predictive models to define four categories (low, medium, high, very high) to plan species conservation. The best distribution and abundance models for both Paleosuchus species included a combination of all predictor sets, except for the best abundance model for P. trigonatus which incorporated only temperature, precipitation, surface water, human impact, and topography. We found non-consistent and low explanatory power of environmental suitability to predict abundance which aligns with previous studies relating SDM-SAM. We extracted the most relevant information from each optimal SDM and SAM and created a consensus model (2,790,583 km2) that we categorized as low (39.6%), medium (42.7%), high (14.9%), and very high (2.8%) conservation priorities. We identified 279,338 km2 where conservation must be critically prioritized and only 29% of these areas are under protection. We concluded that optimal models from correlative methods can be used to provide a systematic prioritization scheme to promote conservation and as surrogates to generate insights for quantifying ecological patterns. 相似文献
18.
Leszek Karczmarski Paul E. D. Winter Victor G. Cockcroft Anton Mclachlan 《Marine Mammal Science》1999,15(4):1115-1123
Mark-recapture analyses were performed on photo-identification data for Indo-Pacific humpback dolphins (Sousa chinensis) inhabiting Algoa Bay, on the Eastern Cape coast of South Africa. Boat-based photo-ID surveys were undertaken between May 1991 and May 1994. The rate of discovery of newly identified dolphins, distribution of sightings and frequency of resightings of known individuals indicate a high level of seasonal immigration of humpback dolphins into, and emigration from, the Algoa Bay region in summer. Consequently, humpback dolphins from Algoa Bay appear to be part of a substantially larger population that uses a considerable length of the coastal zone. The minimum population size is estimated to be about 466 dolphins. 相似文献
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Caroline Rinaldi Renato Rinaldi Juliette Laine Christophe Barbraud 《Marine Mammal Science》2021,37(4):1391-1405
Sperm whales are present along the Caribbean islands in family groups of mature females, juveniles, and newborns. Their abundance and demographic rates remain poorly known. Using photo-identification data, we estimated the abundance and annual survival of sperm whales in Guadeloupe from January to April 2001–2013. A total of 1,492 photographs of tail flukes were scored (ranging from 1 to 5) in terms of quality (Q) and marking (M) level. A total of 789 photographs were selected with Q ≥ 3 and M ≥ 3, corresponding to 109 individually identified adult females or immatures of both sexes. Capture histories were built and analyzed using the Pollock's robust design capture-mark-recapture model. The study consisted of 13 primary periods sequenced in 5–8 secondary periods. Mean annual survival rate of residents was 0.945, 95% CI [0.864, 0.979]. Abundance varied between years from 75 to 35 individuals. The geometric growth rate over the period 2001–2013 was 0.938, 95% CI [0.878, 0.997], suggesting a population decline of −6.2%/year. Sperm whales are moving between Guadeloupe and Dominica, with a high temporary emigration rate (0.163) and 50% of the individuals of Guadeloupe resighted in Dominica. These results highlight the fragility of the population and the necessity to consider it as one unit. 相似文献
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Mia Momberg Peter G. Ryan David W. Hedding Janine Schoombie Kyle A. Goddard Ken J. Craig Peter C. Le Roux 《Ibis》2023,165(1):190-203
Several factors may drive bird nest-site selection, including predation risk, resource availability, weather conditions and interaction with other individuals. Understanding the drivers affecting where birds nest is important for conservation planning, especially where environmental change may alter the distribution of suitable nest-sites. This study investigates which environmental variables affect nest-site selection by the Wandering Albatross Diomedea exulans, the world's largest pelagic bird. Here, wind characteristics are quantitatively investigated as a driver of nest-site selection in surface-nesting birds, in addition to several topographical variables, vegetation and geological characteristics. Nest locations from three different breeding seasons on sub-Antarctic Marion Island were modelled to assess which environmental factors affect nest-site selection. Elevation was the most important determinant of nest-site selection, with Wandering Albatrosses only nesting at low elevations. Distance from the coast and terrain roughness were also important predictors, with nests more generally found close to the coast and in flatter terrain, followed by wind velocity, which showed a hump-shaped relationship with the probability of nest occurrence. Nests occurred more frequently on coastal vegetation types, and were absent from polar desert vegetation (generally above c. 500 m elevation). Of the variables that influence Wandering Albatross nest location, both vegetation type and wind characteristics are likely to be influenced by climate change, and have already changed over the last 50 years. As a result, the availability of suitable nest-sites needs to be considered in light of future climate change, in addition to the impacts that these changes will have on foraging patterns and prey distribution. More broadly, these results provide insights into how a wide range of environmental variables, including wind, can affect nest-site selection of surface-nesting seabirds. 相似文献