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1. Environmental drivers of diving behavior and space-use of juvenile endangered Caribbean hawksbill sea turtles identified using acoustic telemetry

   https://doi.org/10.3354/meps13466  

   Matley, JK ; Jossart, J ; Johansen, L ; Jobsis, PD ( October 2020 , Marine Ecology Progress Series)

   null (Ed.)

   Space-use by aquatic ectotherms is closely linked to environmental factors such as temperature due to thermal-mediated metabolism and energy requirements. These factors are important, as they may alter an animal’s exposure to food/predators, hinder physiological function, increase competitive interactions, or even prompt population or biodiversity loss. Using general linear mixed-effects models, we investigated the influence of medium-term (months-years) environmental (diel period, water temperature, season, wind speed, air pressure, habitat type) and biological (turtle size) variation on space-use metrics for the Critically Endangered hawksbill sea turtle Eretmochelys imbricata , including dive duration, activity space, and rate of movement. We tracked 17 resident juveniles between August 2015 and May 2018 with a compact acoustic telemetry array (35-41 receivers in ~1 km 2 ) in Brewers Bay, US Virgin Islands. Diel differences in space-use were significant and highlighted periods of relative inactivity (e.g. resting) during the night and activity (e.g. foraging) during the day. Water temperature was also an important covariate influencing behavior leading to shorter dive durations and higher rates of movement in warmer temperatures. High contribution of random effects (individual and year) to model variation was also apparent, suggesting that juvenile hawksbills can operate outside the relatively narrow environmental range experienced within the study area. Nevertheless, ongoing climate trends (e.g. warmer temperatures and more extreme weather events) pose a significant concern for hawksbill populations, as juveniles spend their developmental period in shallow nearshore areas where environmental impacts will likely be greatest. 

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2. Movement patterns of juvenile Atlantic tarpon (Megalops atlanticus) in Brewers Bay, St. Thomas, U.S. Virgin Islands

   https://doi.org/10.1186/s40317-021-00239-x  

   Duffing Romero, Mareike D. ; Matley, Jordan K. ; Luo, Jiangang ; Ault, Jerald S. ; Pittman, Simon J. ; Nemeth, Richard S. ( May 2021 , Animal Biotelemetry)

   Atlantic tarpon (Megalops atlanticus) are a highly migratory species ranging along continental and insular coastlines of the Atlantic Ocean. Due to their importance to regional recreational and sport fisheries, research has been focused on large-scale movement patterns of reproductively active adults in areas where they are of high economic value. As a consequence, geographically restricted focus on adults has left significant gaps in our understanding of tarpon biology and their movements, especially for juveniles in remote locations where they are common. Our study focused on small-scale patterns of movement and habitat use of juvenile tarpon using acoustic telemetry in a small bay in St. Thomas, US Virgin Islands.

   Four juvenile tarpon (80–95 cm FL) were tracked from September 2015 to February 2018, while an additional eight juveniles (61–94 cm FL) left the study area within 2 days after tagging and were not included in analysis. Four tarpon had > 78% residency and average activity space of 0.76 km²(range 0.08–1.17 km²) within Brewers Bay (1.8 km²). Their vertical distribution was < 18 m depth with occasional movements to deeper water. Activity was greater during day compared to night, with peaks during crepuscular periods. During the day tarpon used different parts of the bay with consistent overlap around the St. Thomas airport runway and at night tarpon typically remained in a small shallow lagoon. However, when temperatures in the lagoon exceeded 30 °C, tarpon moved to cooler, deeper waters outside the lagoon.

   Our results, although limited to only four individuals, provide new baseline data on the movement ecology of juvenile Atlantic tarpon. We showed that juvenile tarpon had high residency within a small bay and relatively stable non-overlapping daytime home ranges, except when seasonally abundant food sources were present. Fine-scale acoustic tracking showed the effects of environmental conditions (i.e., elevated seawater temperature) on tarpon movement and habitat use. These observations highlight the need for more extensive studies of juvenile tarpon across a broader range of their distribution, and compare the similarities and differences in behavior among various size classes of individuals from small juveniles to reproductively mature adults.

    

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3. Home range characteristics and diel patterns in space use of mutton snapper, Lutjanus analis, in St. Thomas, US Virgin Islands

   https://doi.org/10.1186/s40317-021-00237-z  

   Heidmann, Sarah L. ; Jossart, Jonathan ; Kimble, Melissa ; Nemeth, Richard S. ( December 2021 , Animal Biotelemetry)

   null (Ed.)

   Abstract Background The movement ecology of mutton snapper Lutjanus analis is poorly understood despite their ecological and economic importance in the Caribbean. Passive acoustic telemetry was used to determine home ranges of six adult L. analis , including diel patterns, in Brewers Bay, St. Thomas, US Virgin Islands. Understanding long-term space use, including site fidelity and habitat usage, is necessary to implement effective and appropriate management actions for a species with extensive space and resource needs. Results Individual L. analis were tracked over an average period of 316 days (range 125–509 days) and showed high site fidelity to relatively small home ranges (mean ± SD: 0.103 ± 0.028 km 2 , range 0.019–0.190 km 2 ) and core use areas with low overlap among individuals. Most home ranges had a habitat composition dominated by seagrass and to a lesser degree, coral reef and/or pavement. Nighttime activity spaces were distinct from but contained within daytime areas. Conclusions Mutton snapper showed strong site fidelity to home ranges in Brewers Bay. Two individuals that were absent from the array for more than a few hours were detected at separate arrays at spawning aggregation sites. This study expands upon knowledge of mutton snapper home range characteristics, highlights the importance of maintaining adjacent high-quality habitat types in any spatial management plan, and encourages the adoption of other types of management strategies, particularly for transient-aggregating species. 

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4. Time of night and moonlight structure vertical space use by insectivorous bats in a Neotropical rainforest: an acoustic monitoring study

   https://doi.org/10.7717/peerj.10591  

   Gomes, Dylan G.E. ; Appel, Giulliana ; Barber, Jesse R. ( January 2020 , PeerJ)

   null (Ed.)

   Background Previous research has shown diverse vertical space use by various taxa, highlighting the importance of forest vertical structure. Yet, we know little about vertical space use of tropical forests, and we often fail to explore how this three-dimensional space use changes over time. Methods Here we use canopy tower systems in French Guiana and passive acoustic monitoring to measure Neotropical bat activity above and below the forest canopy throughout nine nights. We use a Bayesian generalized linear mixed effect model and kernel density estimates to demonstrate patterns in space-use over time. Results We found that different bats use both canopy and understory space differently and that these patterns change throughout the night. Overall, bats were more active above the canopy (including Cormura brevirostris, Molossus molossus, Peropteryx kappleri and Peropteryx macrotis ), but multiple species or acoustic complexes (when species identification was impossible) were more active in the understory (such as Centronycteris maximiliani, Myotis riparius, Pteronotus alitonus and Pteronotus rubiginosus ). We also found that most bats showed temporally-changing preferences in hourly activity. Some species were less active (e.g., P. kappleri and P. macrotis ), whereas others were more active ( Pteronotus gymnonotus, C. brevirostris , and M. molossus ) on nights with higher moon illuminance. Discussion Here we show that Neotropical bats use habitat above the forest canopy and within the forest understory differently throughout the night. While bats generally were more active above the forest canopy, we show that individual groups of bats use space differently over the course of a night, and some prefer the understory. This work highlights the need to consider diel cycles in studies of space use, as animals use different habitats during different periods of the day. 

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5. Towns and trails drive carnivore movement behaviour, resource selection, and connectivity

   https://doi.org/10.1186/s40462-022-00318-5  

   Whittington, Jesse ; Hebblewhite, Mark ; Baron, Robin W. ; Ford, Adam T. ; Paczkowski, John ( December 2022 , Movement Ecology)

   Abstract Background Global increases in human activity threaten connectivity of animal habitat and populations. Protection and restoration of wildlife habitat and movement corridors require robust models to forecast the effects of human activity on movement behaviour, resource selection, and connectivity. Recent research suggests that animal resource selection and responses to human activity depend on their behavioural movement state, with increased tolerance for human activity in fast states of movement. Yet, few studies have incorporated state-dependent movement behaviour into analyses of Merriam connectivity, that is individual-based metrics of connectivity that incorporate landscape structure and movement behaviour. Methods We assessed the cumulative effects of anthropogenic development on multiple movement processes including movement behaviour, resource selection, and Merriam connectivity. We simulated movement paths using hidden Markov movement models and step selection functions to estimate habitat use and connectivity for three landscape scenarios: reference conditions with no anthropogenic development, current conditions, and future conditions with a simulated expansion of towns and recreational trails. Our analysis used 20 years of grizzly bear ( Ursus arctos ) and gray wolf ( Canis lupus ) movement data collected in and around Banff National Park, Canada. Results Carnivores increased their speed of travel near towns and areas of high trail and road density, presumably to avoid encounters with people. They exhibited stronger avoidance of anthropogenic development when foraging and resting compared to travelling and during the day compared to night. Wolves exhibited stronger avoidance of anthropogenic development than grizzly bears. Current development reduced the amount of high-quality habitat between two mountain towns by more than 35%. Habitat degradation constrained movement routes around towns and was most pronounced for foraging and resting behaviour. Current anthropogenic development reduced connectivity from reference conditions an average of 85%. Habitat quality and connectivity further declined under a future development scenario. Conclusions Our results highlight the cumulative effects of anthropogenic development on carnivore movement behaviour, habitat use, and connectivity. Our strong behaviour-specific responses to human activity suggest that conservation initiatives should consider how proposed developments and restoration actions would affect where animals travel and how they use the landscape. 

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