Abstract:Coastal ecosystems have drastically declined in coverage and condition across the globe. To combat these losses, marine conservation has recently employed habitat restoration as a strategy to enhance depleted coastal ecosystems. For restoration to be a successful enterprise, however, it is necessary to identify and address potential knowledge gaps and review whether the field has tracked scientific advances regarding best practices. This enables managers, researchers, and practitioners alike to more readily establish restoration priorities and goals. We synthesized the peer-reviewed, published literature on habitat restoration research in salt marshes, oyster reefs, and seagrasses to address three questions related to restoration efforts: (i) How frequent is cross-sector authorship in coastal restoration research? (ii) What is the geographic distribution of coastal restoration research? and (iii) Are abiotic and biotic factors equally emphasized in the literature, and how does this vary with time? Our vote-count survey indicated that one-third of the journal-published studies listed authors from at least two sectors, and 6% listed authors from all three sectors. Across all habitat types, there was a dearth of studies from Africa, Asia, and South America. Finally, despite many experimental studies demonstrating that species interactions can greatly affect the recovery and persistence of coastal foundation species, only one-fourth of the studies we examined discussed their effects on restoration. Combined, our results reveal gaps and discrepancies in restoration research that should be addressed in order to further propel coastal restoration science.

Cuvier's beaked whales exhibit exceptionally long and deep foraging dives. The species is little studied due to their deep-water, offshore distribution and limited time spent at the surface. We used LIMPET satellite tags to study the diving behaviour of Cuvier's beaked whales off Cape Hatteras, North Carolina from 2014 to 2016. We deployed 11 tags, recording 3242 h of behaviour data, encompassing 5926 dives. Dive types were highly bimodal; deep dives (greater than 800 m, n = 1408) had a median depth of 1456 m and median duration of 58.9 min; shallow dives (50–800 m, n = 4518) were to median depths of 280 m with a median duration of 18.7 min. Most surface intervals were very short (median 2.2 min), but all animals occasionally performed extended surface intervals. We found no diel differences in dive depth or the percentage of time spent deep diving, but whales spent significantly more time near the surface at night. Other populations of this species exhibit similar dive patterns, but with regional differences in depth, duration and inter-dive intervals. Satellite-linked tags allow for the collection of long periods of dive records, including the occurrence of anomalous behaviours, bringing new insights into the lives of these deep divers.

We analysed 3680 dives from 23 satellite-linked tags deployed on Cuvier's beaked whales to assess the relationship between long duration dives and inter-deep dive intervals and to estimate aerobic dive limit (ADL). The median duration of presumed foraging dives was 59 min and 5% of dives exceeded 77.7 min. We found no relationship between the longest 5% of dive durations and the following inter-deep dive interval nor any relationship with the ventilation period immediately prior to or following a long dive. We suggest that Cuvier's beaked whales have low metabolic rates, high oxygen storage capacities and a high acid-buffering capacity to deal with the by-products of both aerobic and anaerobic metabolism, which enables them to extend dive durations and exploit their bathypelagic foraging habitats.

Within-species variation in social structure has attracted interest recently because of the potential to explore phenotypic plasticity and, specifically, how demographic and ecological variation influence social structure. Populations of bottlenose dolphins (Tursiops spp.) vary in male alliance formation, from no alliances to simple pairs to, in Shark Bay, Western Australia, the most complex nested alliances known outside of humans. Examination of ecological contributions to this variation is complicated by differences among populations in other potentially explanatory traits, such as phylogenetic distance, as well as female reproductive schedules, sexual size dimorphism, and body size. Here, we report our discovery of systematic spatial variation in alliance structure, seasonal movements and access to mates within a single continuous social network in the Shark Bay population. Participation in male trios (versus pairs), the sizes of seasonal range shifts and consortship rates all decrease from north to south along the 50 km length of the study area. The southern habitat, characterised by shallow banks and channels, may be marginal relative to the open northern habitat. The discovery of variation in alliance behaviour along a spatial axis within a single population is unprecedented and demonstrates that alliance complexity has an ecological component.

Background: Studies of deep-diving beaked whales using Argos satellite-linked location-depth tags frequently return data with large gaps in the diving record. We document the steps taken to eliminate these data gaps and collect weeks of continuous time series data for a behavioral response study that took place in 2017. We used baseline data collected from 2014 to 2016 to analyze message diagnostics, and assess our current programming schedule using a multiple criteria decision making matrix (MCDM), as a robust way to develop a new sampling regime. Results:The MCDM approach suggested animal behavior and the quantity of data collected were the main causes of gaps in our baseline tag records. We implemented a new sampling regime to sample only long-duration, presumed foraging dives, simultaneously increasing temporal coverage of each individual message and reducing the number of messages by 50%. The reduction of gaps increased the data available for continuous time series analysis from an average of just over 2 days and 13.5 sequential presumed foraging dives in our baseline tags to just over 19 days and 118 sequential presumed foraging dives in tags deployed during the 2017 behavioral response study. Conclusions:We demonstrate that a critical approach, based on analysis of baseline data and question-driven weighted criteria, enabled the reduction and even elimination of gaps in the diving records of these tags. This approach enabled us to develop specific settings for our tags to ensure that our data collection was optimized for statistical analysis of the specific hypotheses we were testing.

Male Indo‐pacific bottlenose dolphins in Shark Bay, Western Australia, have converged with humans in the formation of nested male alliances and the use of synchrony in alliance behavior. Further, the strength of association among allied male dolphins varies and the stability of alliances correlates with the rate that males consort with estrus females (and is thus a possible indicator of dominance). To examine the possibility that synchrony reflects alliance association strength and dominance relationships, we analyzed videotapes from focal follows of two groups of males that reflect the range of alliance size and the strength of association between individuals in the population. We examined two variables: leadership during synchronous behaviors, based on which animal in a synchronously surfacing pair surfaced first, and the degree of synchrony, based on temporal differences in synchronous surfacing. We predicted that closer associates would exhibit a greater degree of synchrony and that one dolphin in a dyad would consistently lead. Contrary to our predictions, the degree of synchrony was inversely related to strength of association within alliances. This surprising result suggests that individuals with less secure bonds may strive more to achieve synchrony. We found no evidence of leadership during synchronous surfacing or between synchrony and other behavioral variables. Proximate mechanisms for synchronous behavior, such as entrainment and mutual motor imitation (“the mirror game” paradigm), may inhibit leadership in this context. Our results show that synchrony during surfacing is not a useful behavior to examine for dominance relationships in wild dolphins but it may be a useful tool to examine variation in alliance relationships.

Coalitions and alliances exemplify the core elements of conflict and cooperation in animal societies. Ecological influences on alliance formation are more readily attributed to withinspecies variation where phylogenetic signals are muted. Remarkably, male Indo-Pacific bottlenose dolphins in Shark Bay, Western Australia, exhibit systematic spatial variation in alliance behavior, not simply within a species or population, but within a single social network. Moving SE-NW along Peron Peninsula in Shark Bay, males ally more often in trios than pairs, consort females more often, and exhibit greater seasonal movements. Ecological models predict more male-male conflict in the north, but sufficient observations of aggression are lacking. However, dolphins often incur marks, in the form of tooth rakes, during conflicts. Here we report that the incidence of new tooth rake marks varies systematically in the predicted pattern, with greater marking in the north, where males form more trios and consort females at a higher rate. While our previous work demonstrated that alliance complexity has an ecological component, we can now infer that ecological variation impacts the level of alliance-related conflict in Shark Bay.

Studies of the social behavior of Cuvier's beaked whales (Ziphius cavirostris) are challenging because of their deep‐water habitat usually far from shore and the limited time they spend at the surface. The sociality of these deepest diving mammals is of interest, however, especially for our understanding of how social systems evolve in extreme habitats. High levels of scarring suggest that males compete agonistically for access to females and so we predicted that associations among adult males would be unstable due to competitive exclusion. We tested this prediction by evaluating the diving behavior of animals within social groups off Cape Hatteras, North Carolina, considering diving synchrony a proxy for group membership. Using data from satellite‐linked depth‐recording tags, we found that adult male–male pairs showed extended periods of synchrony in diving behavior, while all pairs that included an adult male with an individual of another age and/or sex dove synchronously for less than a day. We assessed three hypotheses to explain these surprising results: sexual segregation; extended bouts of male–male competition; and the presence of male alliances. Finally, we considered testable predictions to distinguish among these explanations.