Sperm whale Physeter macrocephalus habitat preferences are still poorly understood in the Mediterranean, despite the population being classified as 'Endangered' by the IUCN. Techniques to make the best use of multiple data sources are important in improving this situation. This work provides a detailed evaluation of sperm whale distribution and habitat use around the Balearic Islands using a novel analytical framework that combines transect and follow data while accounting for any autocorrelation present. During dedicated research cruises (2003 to 2008), sperm whales were located by listening at regular intervals along a search track and subsequently followed acoustically. Sperm whales were encountered 56 times and followed for periods ranging from a few hours to 3 d. Logistic Generalized Additive Models were used to model the probability of whale presence across the study area as a function of environmental variables, and Generalized Estimating Equations were used to account for autocorrelation. The results suggest that sperm whales do not use the region uniformly and that topography plays a key role in shaping their distribution. Moreover, solitary individuals were found to use the habitat differently from groups. This segregation appeared to be driven by water temperature and might reflect different needs or intraspecific competition. By shedding light on sperm whale habitat preference in such a critical area, this study represents an important step towards the implementation of conservation measures for this population.KEY WORDS: Habitat modelling · Cetacean · Distribution · Balearic Islands · GAM · GEE · Multi-scale 436: 257-272, 2011 258 archipelago is one of the few areas in the Mediterranean Sea in which both social units and mature males are observed consistently, suggesting a possibly important role as breeding ground (Gannier et al. 2002, Drouot-Dulau & Gannier 2007. Nevertheless, no long-term study has been conducted to date to specifically estimate the species distribution in this region, and thus little information exists on its space use and habitat preferences around the archipelago. Resale or republication not permitted without written consent of the publisherMar Ecol Prog SerHabitat preference modelling techniques represent a useful tool to quantify the relationships between a species and its environment (Guisan & Zimmermann 2000, Redfern et al. 2006, Matthiopoulos & Aarts 2010. Knowing where the animals are, what environmental characteristics influence their choice of habitat and how this choice changes with time is crucial to understanding the species' ecology, identifying the areas of critical importance, assessing the overlap with human activities and, ultimately, guiding appropriate conservation efforts (Redfern et al. 2006). Food availability is probably the main determinant of space use by marine mammals (e.g. Benoit-Bird & Au 2003, Hastie et al. 2004, Frederiksen et al. 2006, Friedlaender et al. 2006. Other potentially important factors affecting habitat choice include beh...
Summary 1.Behavioural change in response to anthropogenic activities is often assumed to indicate a biologically significant effect on a population of concern. Disturbances can affect individual health through lost foraging time or other behaviours, which will impact vital rates and thus the population dynamics. However, individuals may be able to compensate for the observed shifts in behaviour, leaving their health and thus their vital rates and population dynamics, unchanged. 2. We developed a mathematical model simulating the complex social, spatial, behavioural and motivational interactions of coastal bottlenose dolphins (Tursiops truncatus) in the Moray Firth, Scotland, to assess the biological significance of increased rate of behavioural disruptions caused by vessel traffic. 3. We explored a scenario in which vessel traffic increased from 70 to 470 vessels a year in response to the construction of a proposed offshore renewables' facility. Despite the more than sixfold increase in vessel traffic, the dolphins' behavioural time budget, spatial distribution, motivations and social structure remain unchanged. 4. We found that the dolphins are able to compensate for their immediate behavioural response to disturbances by commercial vessels. If the increased commercial vessel traffic is the only escalation in anthropogenic activity, then the dolphins' response to disturbance is not biologically significant, because the dolphins' health is unaffected, leaving the vital rates and population dynamics unchanged. 5. Our results highlight that behavioural change should not automatically be correlated with biological significance when assessing the conservation and management needs of species of interest. This strengthens the argument to use population dynamics targets to manage human activities likely to disturb wildlife.
Summary As part of global efforts to reduce dependence on carbon‐based energy sources there has been a rapid increase in the installation of renewable energy devices. The installation and operation of these devices can result in conflicts with wildlife. In the marine environment, mammals may avoid wind farms that are under construction or operating. Such avoidance may lead to more time spent travelling or displacement from key habitats. A paucity of data on at‐sea movements of marine mammals around wind farms limits our understanding of the nature of their potential impacts.Here, we present the results of a telemetry study on harbour seals Phoca vitulina in The Wash, south‐east England, an area where wind farms are being constructed using impact pile driving. We investigated whether seals avoid wind farms during operation, construction in its entirety, or during piling activity. The study was carried out using historical telemetry data collected prior to any wind farm development and telemetry data collected in 2012 during the construction of one wind farm and the operation of another.Within an operational wind farm, there was a close‐to‐significant increase in seal usage compared to prior to wind farm development. However, the wind farm was at the edge of a large area of increased usage, so the presence of the wind farm was unlikely to be the cause.There was no significant displacement during construction as a whole. However, during piling, seal usage (abundance) was significantly reduced up to 25 km from the piling activity; within 25 km of the centre of the wind farm, there was a 19 to 83% (95% confidence intervals) decrease in usage compared to during breaks in piling, equating to a mean estimated displacement of 440 individuals. This amounts to significant displacement starting from predicted received levels of between 166 and 178 dB re 1 μPa(p‐p). Displacement was limited to piling activity; within 2 h of cessation of pile driving, seals were distributed as per the non‐piling scenario. Synthesis and applications. Our spatial and temporal quantification of avoidance of wind farms by harbour seals is critical to reduce uncertainty and increase robustness in environmental impact assessments of future developments. Specifically, the results will allow policymakers to produce industry guidance on the likelihood of displacement of seals in response to pile driving; the relationship between sound levels and avoidance rates; and the duration of any avoidance, thus allowing far more accurate environmental assessments to be carried out during the consenting process. Further, our results can be used to inform mitigation strategies in terms of both the sound levels likely to cause displacement and what temporal patterns of piling would minimize the magnitude of the energetic impacts of displacement.
Abstract:The first fully automated small-molecule robotic X-ray diffractometer is described. After demonstrating the utility of the instrument using multiple samples of ammonium bitartrate we investigated the conformational chirality of diphenyl dichalcogenide (E2Ph2, where E = S, Se, or Te). Structural and computational studies suggest that the two enantiomers are energetically indistinguishable. Therefore, it was unsurprising that we found (in 35 suitable data collections) the proportion 0.51:0.49 of M-S2Ph2 to P-S2Ph2 in the bulk sample. Interestingly, after 65 data collections of Te2Ph2, (46 provided suitable data sets), we found the proportion 0.72 ± 0.13 of M-Te2Ph2, Suggesting there could be a statistically significant preference for the M-enantiomer in the sample examined here. We found that Se2Ph2 underwent homochiral crystallization with all 24 crystals being M. Our experiments may represent a salutary lesson in statistical analysis.
4Conventional smoothing over complicated coastal and island regions may result in errors across
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.