scholarly journals Manual Acoustic Tracking Reveals the Spatial Ecology of Giant Trevally at a Remote South Pacific Atoll, with Implications for Their Management

2019 ◽  
Author(s):  
Alexander Filous ◽  
Robert J. Lennox ◽  
Andy J. Danylchuk ◽  
Alan M. Friedlander

<div>Giant trevally (<i>Caranx ignobilis</i>) are important predators on the reefs of the tropical Indo-Pacific and research into their spatial ecology is needed to improve our understanding of their behavior and assist fisheries management. We used active acoustic telemetry to describe the fine-scale movements of giant trevally at Tetiaroa Atoll, including their home range, site fidelity, habitat use and spatial overlap with a small (21 km2) Marine Protected Area (MPA). The home ranges of giant trevally were small but varied among individuals (Minimum Convex Polygon 𝑋𝑋 = 3.2 ± 2.5 km2). All giant trevally exhibited site fidelity to their respective home ranges with a 31% average overlap in daily space use, but there was limited overlap in home ranges among individuals, with intra-individual spatial overlap significantly greater than inter-individual overlap (t = -4.93, df = 16.87, p-value = <0.001). There was only modest overlap (19 ± 19%) of giant trevally home ranges within the MPA and high spatial overlap of home ranges with deep lagoon habitats (90 ± 0.09 %). Our results indicate that MPAs could be an effective tool for the conservation of this species if they are implemented on an atoll-wide scale. However, in the case of managing recreational catch-and-release fisheries, rotational smallscale temporal closures could be effective in regulating the angling pressure imposed upon giant trevally, provided post-release mortality is minimized. The results of this study provide the first detailed account of habitat use in this species and highlight the need for additional research on the factors contributing to the survival of caught-and-released giant trevally in predator dominated atolls, especially as their popularity as a target of recreational fisheries continues to grow, and fishing operations and agencies are faced with the need to manage their fisheries.</div>

2019 ◽  
Author(s):  
Alexander Filous ◽  
Robert J. Lennox ◽  
Andy J. Danylchuk ◽  
Alan M. Friedlander

<div>Giant trevally (<i>Caranx ignobilis</i>) are important predators on the reefs of the tropical Indo-Pacific and research into their spatial ecology is needed to improve our understanding of their behavior and assist fisheries management. We used active acoustic telemetry to describe the fine-scale movements of giant trevally at Tetiaroa Atoll, including their home range, site fidelity, habitat use and spatial overlap with a small (21 km2) Marine Protected Area (MPA). The home ranges of giant trevally were small but varied among individuals (Minimum Convex Polygon 𝑋𝑋 = 3.2 ± 2.5 km2). All giant trevally exhibited site fidelity to their respective home ranges with a 31% average overlap in daily space use, but there was limited overlap in home ranges among individuals, with intra-individual spatial overlap significantly greater than inter-individual overlap (t = -4.93, df = 16.87, p-value = <0.001). There was only modest overlap (19 ± 19%) of giant trevally home ranges within the MPA and high spatial overlap of home ranges with deep lagoon habitats (90 ± 0.09 %). Our results indicate that MPAs could be an effective tool for the conservation of this species if they are implemented on an atoll-wide scale. However, in the case of managing recreational catch-and-release fisheries, rotational smallscale temporal closures could be effective in regulating the angling pressure imposed upon giant trevally, provided post-release mortality is minimized. The results of this study provide the first detailed account of habitat use in this species and highlight the need for additional research on the factors contributing to the survival of caught-and-released giant trevally in predator dominated atolls, especially as their popularity as a target of recreational fisheries continues to grow, and fishing operations and agencies are faced with the need to manage their fisheries.</div>


2007 ◽  
Vol 28 (4) ◽  
pp. 531-536 ◽  
Author(s):  
Ulrich Schulte ◽  
Daniel Küsters ◽  
Sebastian Steinfartz

Abstract We studied patterns of annual movement of individual adult fire salamanders (Salamandra salamandra) during the years 2001 and 2002 in Western Germany in a typical middle European habitat for this species. We tested whether salamanders inhabit small home ranges and move little during the activity period as predicted for a species that shows strong site fidelity to a limited area. Initially, 98 individuals were collected in their natural habitat and marked with passive integrated transponder (PIT) tags. Of those individuals 88 were released at the collection site for recapture during the activity periods of the years 2001 and 2002. Ten marked individuals were kept in captivity to test for the tolerance of PIT tags. We did not find any negative impact of PIT tags on marked individuals of S. salamandra, neither under captive nor natural conditions. Forty-seven of the marked individuals (corresponding to 53% of the 88 released ones) were recaptured at least once and 28 individuals (corresponding to 32%) were recaptured multiple times. The return rate of males (78%) was higher than for females (43%). Mean home range size (and standard deviation) was estimated to 494 ± 282 m2 for 4 individuals as the minimum convex polygon based on 5 to 6 recapture events for each individual per year and to 1295 ± 853 m2 for 3 individuals with 8 records over two years. Minimum distances moved inferred from individual recaptures increased during the activity period of both years with time, indicating that individuals have more of a tendency to disperse than to stay within a limited area. Our data suggest therefore that S. salamandra adults display site fidelity, but use a much larger area than hitherto documented for this and other terrestrial salamander species.


2019 ◽  
Vol 101 (1) ◽  
pp. 151-163 ◽  
Author(s):  
A L J Desbiez ◽  
D Kluyber ◽  
G F Massocato ◽  
L G R Oliveira-Santos ◽  
N Attias

Abstract The giant armadillo (Priodontes maximus) is the largest living armadillo. This naturally rare and poorly known species is endemic to South America and classified as “Vulnerable” by the IUCN. Here we explored aspects of the spatial ecology of P. maximus in Midwestern Brazil to gain insights on its ecology and biology to support conservation efforts. In 8 years, we identified 50 individuals of P. maximus and monitored 23 of them using telemetry methods. To characterize site fidelity and home range, we fitted individual continuous-time movement models and estimated Autocorrelated Kernel Density Estimates. We built a Structural Equation Model to evaluate how home-range area and daily displacement are related to each other, to sampling effort, and to individual characteristics. We estimated home-range overlap between pairs of different sexes using a bias-corrected Bhattacharyya coefficient. Finally, we formulated a canonical density estimation formula to characterize minimum population density. We gathered a total of 12,168 locations of P. maximus. The best-fitted movement models indicated site fidelity for all individuals and a median adult home-range area of 2,518 ha. Median adult daily displacement was 1,651 m. Home-range area scales positively with daily displacement and daily displacement scales positively with body mass. Median home-range overlap between pairs was low (4%) and adult females presented exclusive home ranges among themselves. Median minimum density was 7.65 individuals per 100 km2 (CI = 5.68–10.19 ind/100 km2). Our results are congruent with characterizing P. maximus as a generally asocial species, most likely promiscuous/polygynous, that establishes large, long-term home ranges, which grants the population a naturally low density. Spatial patterns and biological characteristics obtained in this study can be used to guide future conservation strategies for P. maximus in the Pantanal wetlands and elsewhere.


The Auk ◽  
2019 ◽  
Vol 136 (2) ◽  
Author(s):  
Csaba Moskát ◽  
Miklós Bán ◽  
Attila Fülöp ◽  
Judit Bereczki ◽  
Márk E Hauber

Abstract Obligate brood parasitic birds have evolved a rare avian strategy for reproduction by laying eggs in the nests of other species. In doing so, their breeding ranges, but not necessarily their foraging habitats, have become intimately related to the nesting territories of their hosts. We studied home range sizes and distribution patterns in Common Cuckoos (Cuculus canorus) on their breeding grounds in central Hungary, where cuckoos parasitize only Great Reed Warblers (Acrocephalus arundinaceus) in channel-side reed-beds at a high frequency (>50%). The geographic coordinates of tagged cuckoos were monitored by high-precision, remotely downloadable non-Platform Terminal Transmitter global positioning system (GPS) loggers, attached to 9 females and 6 males. Our results revealed bimodal use of habitat patches: (1) the home ranges of male and female cuckoos were packed densely along the channels where the hosts breed, and their distribution maps had high overlaps between sexes; (2) ~71% of cuckoos also visited nearby woodland patches, presumably for foraging, where the host species was not present. The size of cuckoo home ranges varied to an unusually great extent: 0.3–185 km2 as calculated by the minimum convex polygon method (85%), or 1–17 km2 when calculated by the more suitable kernel density estimation (KDE) method (Utilization Distribution 85%) for patchy habitats. Male and female cuckoos had similar home range sizes as estimated by the KDE method, consisting of 1–4 areas within the 2 habitat types of channel reed-beds and woodlands. No preference was revealed for night roosting locations between the 2 habitats or sexes. Female cuckoos were more likely to use reed-beds in the afternoons, when females parasitize host nests. Remote downloadable GPS methods offer an effective way of tracking cuckoos across large areas, but the estimation of home range sizes requires caution due to this species’ patchy and disconnected habitat use.


2012 ◽  
Vol 90 (3) ◽  
pp. 337-344 ◽  
Author(s):  
Amariah A. Lebsock ◽  
Christopher L. Burdett ◽  
Safi K. Darden ◽  
Torben Dabelsteen ◽  
Michael F. Antolin ◽  
...  

Space use is a fundamental characteristic that informs our knowledge of social relationships and the degree to which individuals are territorial. Until recently, relatively little was known about the spatial ecology and social organization of swift foxes ( Vulpes velox (Say, 1823)). We investigated space use of swift foxes on shortgrass prairie in northeastern Colorado. Our first objective was to evaluate sizes of seasonal and annual home ranges and core areas of 13 radio-collared swift foxes monitored continuously for 2 years. Our second objective was to compare home-range and core-area overlap of breeding pairs to that of neighboring foxes, including male–male, female–female, and nonbreeding female–male dyads. Home-range size in our study population was among the smallest previously reported for swift foxes. Males tended to have slightly larger home ranges and core areas than females, and home-range size was significantly larger in the breeding season than in both the pup-rearing and the dispersal seasons; sizes of core areas did not differ seasonally. Spatial overlap between breeding pairs was substantial, whereas spatial overlap between neighbors, particularly males, was low, suggesting territoriality.


2015 ◽  
Vol 42 (6) ◽  
pp. 500 ◽  
Author(s):  
Desley A. Whisson ◽  
Michael A. Weston ◽  
Kelly Shannon

Context In peri-urban environments, high availability of anthropogenic resources may result in relatively high abundances of some species, with potentially negative implications for other native biota. Effective management of such impacts requires understanding of the spatial ecology of problem species. However, home range and habitat use have not been described for the little raven (Corvus mellori), a superabundant native predator that occurs in urban and natural habitats, including those where threatened shorebirds breed. Aims The aim of this study was to provide basic information on little raven home range, habitat use and movements in a coastal peri-urban landscape. Methods Between October 2011 and January 2012 we radio-tracked 20 little ravens captured in a coastal wetland (near Melbourne, Australia). Key results Little ravens were highly mobile, moving up to 9.9 km in an hour (median = 2 km), and had large ranges: Minimum Convex Polygons were 1664–9989 ha (median = 3362 ha). Although most birds used both anthropogenic and natural habitats, some birds strongly selected for coastal wetland habitat. Birds used multiple roosts during the study period, most of which occurred in grassland (58.7%) or urban (22.3%) areas. Movement of up to 8.3 km (median = 2.2 km) between roosts during the night was also detected. Conclusions Ravens were highly mobile and used large home ranges and a variety of habitats, with habitat preferences varying between birds. Implications Considering the large home ranges and inter-individual variation in habitat preferences of little raven populations, localised management to reduce their impacts on breeding shorebirds is unlikely to be successful.


Therya ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 553-562
Author(s):  
César R. Rodríguez-Luna ◽  
Jorge Servin ◽  
David Valenzuela-Galván ◽  
Rurik List

Coyotes (Canis latrans) and gray foxes (Urocyon cinereoargenteus) are abundant and widely distributed in México, with no information currently available about their spatial interactions in the country.  Our objectives were to evaluate the habitat use of these species and the environmental interactions between them throughout the overlapping areas of their home ranges in temperate forests of Durango, México.  We expected that their coexistence would be facilitated by the spatial segregation of their ecological niche, exhibited by the low or nil overlap between their home ranges or by differentiated habitat use.  Radio-collars (VHF) were attached to nine individuals — four coyotes (two males and two females) and five gray foxes (females) — that were radio-tracked from September 2017 to August 2019.  We estimated their home ranges and the size of their core areas through the minimum convex polygon and determined the extent of overlap between them.  Also, we evaluated third-order habitat selection and use based on habitat availability using Manly’s habitat-selection ratios and simultaneous Bonferroni confidence intervals (95 %).  The mean home range size for coyotes was larger (12.2 ± 1.74 km2) than for gray boxes (5.3 ± 0.67 km2); the interspecific mean overlap was 42 % (moderate).  Of these two canids, just the gray fox showed a markedly selective habitat use.  Our findings revealed a moderate overlap between the home ranges of both canids, so spatial segregation did not occur.  Although a differential habitat use was observed, explaining the coexistence between these two canids in the areas where they thrive, they tend to avoid agonistic interactions.


Author(s):  
Dominik Krupiński ◽  
Dorota Kotowska ◽  
Mariano R. Recio ◽  
Michał Żmihorski ◽  
Przemysław Obłoza ◽  
...  

AbstractAgriculture intensification drives changes in bird populations but also in the space use by farmland species. Agriculture in Eastern Europe still follows an extensive farming model, but due to policy shifts aimed at rural restructuring and implementation of government subsidies for farmers, it is being rapidly intensified. Here, we aimed to document the ranging behaviour and habitat use of a declining farmland bird of prey—Montagu’s Harrier—and to compare it to findings from Western Europe. In 2011–2018, 50 individuals were followed with GPS loggers in Eastern Poland to study species spatial ecology. We found home ranges (kernel 90%) to be considerably large: 67.3 (± 42.3) km2 in case of males, but only 4.9 (± 6.1) km2 in females. Home ranges overlapped by 40%, on average, with other males in colonies and by 61%, on average, between consecutive breeding seasons of a particular male. The average daily distance travelled by males and females reached, respectively, 94.5 and 45.3 km, covering a daily home range of 32.3 and 3.1 km2. Individuals foraged up to 35 km from nests (3.5 km on average). Daily distance travelled and daily home ranges varied across the breeding season, in case of females being shortest in July, but sharply increasing in August. Also, individuals with breeding success had higher daily distance travelled but smaller daily home ranges. Average harriers’ distance to nest was generally increasing over the season, but was also changing over time of day: birds were closest to nest during night time, but at the end of the season, males roosted up to 16 km from the nest. While foraging males slightly preferred grasslands, higher elevation and smaller land-use patches, they avoided slopes and proximity of roads. We conclude that the surprisingly large home ranges of breeding harriers may suggest reduced prey availability or high fragmentation of hunting areas, both driving birds to utilise large areas and potentially contributing to population decline.


2019 ◽  
Vol 609 ◽  
pp. 239-256 ◽  
Author(s):  
TL Silva ◽  
G Fay ◽  
TA Mooney ◽  
J Robbins ◽  
MT Weinrich ◽  
...  

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