scholarly journals Ontogenetic Shifts in Home Range Size of a Top Predatory Reef-associated Fish (Caranx ignobilis): Implications for Conservation.

2020 ◽  
Author(s):  
Ryan Daly ◽  
John David Filmalter ◽  
Lauren R Peel ◽  
Bruce Quinten Mann ◽  
James Lea ◽  
...  

Abstract Defining the home range of vulnerable species is critical for designing effective spatial management strategies. However, animal home ranges often change with ontogeny and quantifying the associated temporal and spatial changes is particularly challenging for mobile marine species. Here, we investigate how the space use of a top predatory reef-associated fish (Caranx ignobilis) scales with body size. We tagged 17 individuals, representing a wide range of sizes (40.5 – 120 cm fork length (FL)), with acoustic transmitters, and passively tracked them for over 3 years at a tropical island and atoll in the Republic of Seychelles, Western Indian Ocean. We found that a sheltered atoll environment was critical for juvenile fish (< 60 cm FL) that exhibited a shift in home range location and area as they matured into adults. Small (60 – 100 cm FL) and large (> 100 cm FL) adult fish appeared to favour shallow coral reefs and associated reef drop offs whilst sharing a similar core home range location. Large adult fish, however, utilized a greater diversity of habitat types and had significantly (p < 0.05) greater annual dispersal distances (mean = 35.29 km, max = 91.32 km) than small adults (mean = 13.72 km, max = 21.55 km). Additionally, the home range (represented by minimum convex polygons) of large adults (mean = 209.74 km2) was significantly (p < 0.05) larger than that of juveniles (mean = 38.73 km2) and small adults (77.32 km2) and there was a significant (p = 0.02) relationship between fish length and home range size, with fish length accounting for 32% of the home range size variance. Furthermore, tagged fish took up to 34 months (mean = 18.54) to utilize the full extent of their home range. The habitat shift and expansion in home range size throughout ontogeny exhibited by C. ignobilis in this study should be taken into account when designing effective spatial management plans for the species.

Acrocephalus ◽  
2015 ◽  
Vol 36 (166-167) ◽  
pp. 109-132
Author(s):  
Mojca Podletnik ◽  
Damijan Denac

In 2012 and 2013, the selection of foraging habitats and the diet of the Hoopoe Upupa epops were studied in the Goričko area, where a significant population decline of the species has been recorded in the past 15 years. Goričko is an area with a well-preserved traditional mosaic-like agricultural landscape very rich in biodiversity which, however, is disappearing. The diet was determined using automatic camera recordings of prey brought to chicks by parents. Mole crickets Gryllotalpa gryllotalpa were the most dominant prey (35.4% frequency and 81.3% biomass of prey), followed by Scarab beetles larvae Scarabaeidae, caterpillars Lepidoptera larvae and True flies Diptera. Feeding frequency was highest in the period of most intensive chick growth (between 8 and 21 days of age). Selection of foraging habitat was researched by observation of birds during foraging. Hoopoes foraged mostly in mown meadows and grassy courtyards and, to a lesser extent, on sandy cart tracks and road edges. These habitats were characterized by low vegetation and patches of bare ground that enabled Hoopoes to forage efficiently. Home range size was determined using minimum convex polygons. The maximum home range size was between 42.9 and 57.7 ha, while the percentage of foraging habitats within the home range did not exceed 18%. Based on our results, we propose the following measures for effective Hoopoe conservation in the area: maintaining the present range of existing unimproved meadows, stopping the conversion of meadows into fields, restoring fields to meadows, prohibiting the use of pesticides targeting Mole crickets.


2008 ◽  
Vol 122 (1) ◽  
pp. 61 ◽  
Author(s):  
Matthew Schuler ◽  
Richard P. Thiel

Most studies of home ranges occur over short time periods and may not represent the spacial requirements of long-lived organisms such as turtles. Home ranges of 18 individual Blanding’s Turtles (Emydoidea blandingii) were measured using minimum convex polygons. Annual space use was compared to multi-year space use by individual turtles. We found a significant difference between annual home range size (25.5 hectares) and multi-year (two to six years) home range size (65.7 hectares; n = 18, P = 0.016). Caution should be employed when making management decisions based on short-term studies of long lived species.


Oryx ◽  
2014 ◽  
Vol 48 (3) ◽  
pp. 370-377 ◽  
Author(s):  
Achara Simcharoen ◽  
Tommaso Savini ◽  
George A. Gale ◽  
Saksit Simcharoen ◽  
Somphot Duangchantrasiri ◽  
...  

AbstractTigers Panthera tigris are highly threatened and continue to decline across their entire range. Actions to restore and conserve populations need to be based on science but, in South-east Asia, information on ecology and behaviour of tigers is lacking. This study reports the relationship between the home range size of female tigers and prey abundance, using data from radio-collared tigers in Huai Kha Khaeng Wildlife Sanctuary, Thailand, and published data from other studies. A total of 11 tigers, four males and seven females, were fitted with global positioning system collars, to estimate home ranges using 95 and 100% minimum convex polygons (MCP). Prey abundance was estimated by faecal accumulation rates. The mean home range size of male tigers was 267 and 294 km2 based on 95 and 100% MCPs, respectively; the mean female home range size was 70 and 84 km2, respectively. Territories of male and female tigers had little overlap, which indicated both sexes were territorial. Mean densities of the prey species sambar Rusa unicolor, barking deer Muntiacus muntjac and large bovids were 7.5, 3.5 and 3.0 km−2, respectively. When female home range size and prey abundance were compared at six locations in Thailand, and at other sites in India, Nepal, Bangladesh and Russia, a significant negative correlation was found between prey abundance and home range size. Monitoring this relationship can provide managers with metrics for setting conservation goals.


Author(s):  
Ivan V. Seryodkin ◽  
Yuriy K. Kostyria ◽  
John M. Goodrich ◽  
Yuriy K. Petrunenko

Proper management of brown bear populations (Ursus arctos) requires knowledge of their ecology, including space use. Brown bear spatial patterns are particularly poorly understood in the Russian Far East, due to lack of telemetry studies. The aim of this work was to study space use by brown bears in the Sikhote-Alin region. From 1993 to 2002, we used VHF radiocollars to collect spatial data from nine males (eight adults and one juvenile) and six females (five adults and one juvenile) in the Middle Sikhote-Alin. Fixed Kernel home range size estimates were larger for males (891.34 ± 346.99 km2) than for females (349.94 ± 543.06 km2). The juvenile home range sizes were 237.24 and 333.64 km2 for the male and female, respectively. The maximum home range size was for the two-year area of one male (9217.36 km2). The core area sizes varied over a wide range (6.12–358.45 km2). The structure and location of home ranges and their core areas depended upon the seasonal habitat selection of bears, as well as the distribution, abundance, and accessibility of foraging resources. Bears’ home ranges overlapped between males and females, as well as between same sex individuals. The results of this work are important for the management of the brown bear population in the Sikhote-Alin


1993 ◽  
Vol 20 (5) ◽  
pp. 571 ◽  
Author(s):  
S Troy ◽  
G Coulson

Home range in the swamp wallaby, Wallabia bicolor (Marsupialia : Macropodoidea) was examined using radio-tracking in a 150-ha remnant of mixed eucalypt forest at Healesville, Victoria. Three methods were used to calculate home-range size: minimum convex polygons, fourier transform MAP(O.95) and MAP(0.50) estimation, and harmonic mean 50% isopleths and 95% isopleths. The minimum convex polygon method produced the largest estimate of home-range area (16.01 +/-.45 ha). Each method required a different number of fixes before home-range area estimates reached an asymptote. These data showed that W. bicolor have small, overlapping home ranges and that the shape of the home range varied between individuals. Home-range area was larger than previously reported for this species, and there was no significant difference between the sexes in home-range size.


2018 ◽  
Vol 11 (3) ◽  
pp. 204-218 ◽  
Author(s):  
D. Emin ◽  
A.G. Toxopeus ◽  
Ir.T.A. Groen ◽  
I. Kontogeorgos ◽  
E. Georgopoulou ◽  
...  

The Long-eared Owl (Asio otus) in Crete (Greece) is a common agricultural species affected by the recent changes in agro-forestry systems. Concrete studies of habitat selection are needed in order to improve our knowledge of its foraging behaviour in managed rural landscapes. In the present study, we analysed the home range size and habitat selection of 11 Long-eared Owls inside olive groves in the plain of central Crete using radio tracking data and remote sensing images. Six nominal scale and 11 landscape scale predictors were used for habitat selection analysis, using a maximum entropy approach. Home range size ranged between 337 and 969 ha while a 52% of home range overlap was observed suggesting that Long-eared Owls do not defend hunting territories. At the nominal scale, distance to potential roosts (trees) was the most important contributor to model performance, followed by vegetation heterogeneity. Furthermore, local heterogeneity of greenness was a better predictor than simply greenness at the presence location. At the landscape scale the amount of habitat openness significantly improved model performance. Incorporating landscape heterogeneity improved habitat selection prediction compared to using only discrete land cover classification. Results of our study pinpoint that although Long-eared Owls exhibit a wide range of habitat tolerance, they prefer mixed habitat conditions avoiding particularly open areas or dense olive plantations. The research has implications in the face of new reforms of European Common Agricultural policy which emphasised the importance of landscape structure in preserving biodiversity in agricultural areas of Europe.


2019 ◽  
Vol 20 (2) ◽  
pp. 351
Author(s):  
Marina Kipson ◽  
Martin Šálek ◽  
Radek Lučan ◽  
Marcel Uhrin ◽  
Edita Maxinová ◽  
...  

Author(s):  
Matthew S. Kendall ◽  
Laughlin Siceloff ◽  
Ashley Ruffo ◽  
Arliss Winship ◽  
Mark E. Monaco

AbstractSurprisingly, little is known about basic life history of the largest moray eel species in the Caribbean region, the green moray eel (Gymnothorax funebris). Sixteen eels were captured from the mangrove fringe in multiple bays on St. Croix, USVI, implanted with coded acoustic transmitters, and their movements were tracked for up to 11 months using an array of 37 stationary acoustic receivers. They exhibited high site fidelity in the bays during their residence, using the same general parts of individual bays and did not switch bays except for one individual. There was no relationship between eel size (mean TL = 83 cm, range = 54–126 cm) and home range size (mean area of 95% KUD = 5.8 ha ± 0.7 SE). Most individuals were more frequently detected at night than during the day suggesting greater nocturnal activity. Several of the larger eels (mean TL = 93 cm ± 5.9 SE) showed clear and permanent emigration tracks out of the mangrove estuary to coral reef habitats offshore. For some individuals, these habitat shifts were preceded by exploratory movements away from the eel’s typical home range the night before emigration. All final emigration events took place nocturnally, happened during a single night, and occurred during months from December to May. Mean emigration speed was 3.4 km/h. This study is the first documentation of an ontogenetic habitat shift in moray eels, as well as the first determination of home range size for this species and their site fidelity in mangrove habitats.


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