scholarly journals A Pilot Study on Home Range and Habitat Use of Chinese Goral (Naemorhedus Griseus): Exploring GPS Tracking Data in Cliff Landscape by Three Estimation Methods

2021 ◽  
Author(s):  
Yang Teng ◽  
Shupei TANG ◽  
Dalai Menghe ◽  
Liji Wu ◽  
Zhiqing HAN ◽  
...  
Keyword(s):  
Home Range ◽  
Habitat Use ◽  
Estimation Methods ◽  
Conservation Strategies ◽  
Gps Tracking ◽  
Tracking Data ◽  
Size Estimation ◽  
Range Estimation ◽  
Lower Altitude ◽  
Effective Conservation

Abstract Home range size estimation is a crucial basis for developing effective conservation strategies and provides important insights into animal behavior and ecology. This study aimed at analyzing the home range variations, the influence of altitude in habitat selection, and comparing three methods in home range estimation of Chinese gorals (Naemorhedus griseus) living at a cliff landscape. The results indicated that there were significant differences between the annual home range sizes of individual animals but there was no difference in their seasonal home range sizes based on GPS tracking data of five female Chinese gorals from February 2015 to September 2018. The monthly home ranges decreased dramatically in May, June and July due to birth-giving. Notable seasonal variations were found in the micro-habitats of the Chinese gorals, as reflected by the altitude they inhabit, with higher altitude habitats used in spring and lower altitude habitats used in winter. Additionally, the altitude of monthly habitats was lowest in January, which may indicate an adaptation to low air temperature. We also found differences between estimation methods, namely minimum convex polygon (MCP), kernel density estimation (KDE) and α-local convex hull (α-LoCoH), with seasonal home range sizes derived from α-LoCoH being substantially smaller than those derived from MCP and KDE. In conclusion, our findings filled the gaps in home range study for this endangered species and contributed to effective conservation strategies. Considerations shall have to be given to the variations in home range estimation caused by different methods when dealing with rugged habitats, so as to make sure that any interpretation concerning the habitat use of the targeted species made on basis of such results would be meaningful and valid.

scholarly journals A Pilot Study on Home Range and Habitat Use of Chinese Goral (Naemorhedus Griseus): Exploring GPS Tracking Data in Cliff Landscape by Three Estimation Methods

2021 ◽  
Author(s):  
yang teng ◽  
Shupei TANG ◽  
lai heda meng ◽  
Liji Wu ◽  
Zhiqing HAN ◽  
...  
Keyword(s):  
Home Range ◽  
Habitat Use ◽  
Estimation Methods ◽  
Conservation Strategies ◽  
Gps Tracking ◽  
Tracking Data ◽  
Size Estimation ◽  
Range Estimation ◽  
Lower Altitude ◽  
Effective Conservation

Abstract Home range size estimation is a crucial basis for developing effective conservation strategies and provides important insights into animal behavior and ecology. This study aimed at analyzing the home range variations, the influence of altitude in habitat selection, and comparing three methods in home range estimation of Chinese gorals (Naemorhedus griseus) living at a cliff landscape. The results indicated that there were significant differences between the annual home range sizes of individual animals but there was no difference in their seasonal home range sizes based on GPS tracking data of five female Chinese gorals from February 2015 to September 2018. The monthly home ranges decreased dramatically in May, June and July due to birth-giving. Notable seasonal variations were found in the micro-habitats of the Chinese gorals, as reflected by the altitude they inhabit, with higher altitude habitats used in spring and lower altitude habitats used in winter. Additionally, the altitude of monthly habitats was lowest in January, which may indicate an adaptation to low air temperature. We also found differences between estimation methods, namely minimum convex polygon (MCP), kernel density estimation (KDE) and α-local convex hull (α-LoCoH), with seasonal home range sizes derived from α-LoCoH being substantially smaller than those derived from MCP and KDE. In conclusion, our findings filled the gaps in home range study for this endangered species and contributed to effective conservation strategies. Considerations shall have to be given to the variations in home range estimation caused by different methods when dealing with rugged habitats, so as to make sure that any interpretation concerning the habitat use of the targeted species made on basis of such results would be meaningful and valid.

scholarly journals ctmmweb: A graphical user interface for autocorrelation-informed home range estimation

2020 ◽  
Author(s):  
Justin M. Calabrese ◽  
Christen H. Fleming ◽  
Michael J. Noonan ◽  
Xianghui Dong
Keyword(s):  
Home Range ◽  
Kernel Density ◽  
R Package ◽  
Home Ranges ◽  
Tracking Data ◽  
Sampled Data ◽  
Convex Polygons ◽  
Range Estimation ◽  
Empirical Reality ◽  
Range Overlap

ABSTRACTEstimating animal home ranges is a primary purpose of collecting tracking data. All conventional home range estimators in widespread usage, including minimum convex polygons and kernel density estimators, assume independently sampled data. In stark contrast, modern GPS animal tracking datasets are almost always strongly autocorrelated. This incongruence between estimator assumptions and empirical reality leads to systematically underestimated home ranges. Autocorrelated kernel density estimation (AKDE) resolves this conflict by modeling the observed autocorrelation structure of tracking data during home range estimation, and has been shown to perform accurately across a broad range of tracking datasets. However, compared to conventional estimators, AKDE requires additional modeling steps and has heretofore only been accessible via the command-line ctmm R package. Here, we introduce ctmmweb, which provides a point-and-click graphical interface to ctmm, and streamlines AKDE, its prerequisite autocorrelation modeling steps, and a number of additional movement analyses. We demonstrate ctmmweb’s capabilities, including AKDE home range estimation and subsequent home range overlap analysis, on a dataset of four jaguars from the Brazilian Pantanal. We intend ctmmweb to open AKDE and related autocorrelation-explicit analyses to a wider audience of wildlife and conservation professionals.

Habitat use and selection by takin in the Qinling Mountains, China

2016 ◽  
Vol 43 (8) ◽  
pp. 671 ◽  
Author(s):  
Wen-Bo Yan ◽  
Zhi-Gao Zeng ◽  
Hui-Sheng Gong ◽  
Xiang-Bo He ◽  
Xin-Yu Liu ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Home Range ◽  
Habitat Use ◽  
Landscape Scale ◽  
Conservation Strategies ◽  
Large Species ◽  
Qinling Mountains ◽  
Habitat Types ◽  
Forest Habitats ◽  
Selection Of

Context Understanding habitat use and selection by threatened ungulates is a crucial prerequisite to prioritise management areas and for developing effective conservation strategies. Aims The aim of our research was to determine the habitat use and selection of takins (Budorcas taxicolor) in the middle range of the Qinling Mountains, China. Methods The study was conducted from August 2013 to August 2015. Global positioning system (GPS) radio-tracking was used to monitor 10 collared takins to gain their location information. The Manly–Chesson selectivity index and Bonferroni-adjusted 95% confidence intervals were applied to determine which habitats were selected. Key results Habitat use and selection by takins showed obvious individual differences. At the landscape scale, all of the four most common habitat types were preferred by takins. However, all takins avoided artificially planted larch forest, and farmland and village. Available habitats within the home ranges also mostly included the four common habitat types. At the home-range scale, all individuals had significant habitat selectivity during the entire tracking period and each season. The habitat use and selection within the home range varied obviously with season and showed sexual differences to a certain extent. Conclusions The habitat selection by takins is scale-dependent. At the landscape scale, takins are most likely to occur at sites covered by forest. At both landscape and home-range scales, our results indicated that takins need more diverse forest habitats, but none of the four most common forest habitats is essential for survival of this species. Implications The present work has provided more insight into the habitat use and habitat selection of takins in mountainous forest landscapes. Many measures such as maintaining a diversity of forest habitats, avoiding habitat alteration by invasion of exotic plants, and increasing the area of available habitats by relocating the villages from within to outside of the reserve are recommended to conserve this large species.

scholarly journals Home Range of the Spur-Thighed Tortoise, Testudo graeca (Testudines, Testudinidae), in the National Park of El Kala, Algeria

2017 ◽  
Vol 51 (1) ◽  
pp. 45-52
Author(s):  
R. Rouag ◽  
N. Ziane ◽  
S. Benyacoub
Keyword(s):  
Home Range ◽  
Habitat Use ◽  
Population Ecology ◽  
National Park ◽  
Sexual Difference ◽  
Conservation Strategies ◽  
Home Ranges ◽  
Vulnerable Species ◽  
Testudo Graeca ◽  
Northeastern Algeria

Abstract Spur-thighed tortoise is a vulnerable species, the local declines of populations require an imperative need for conservation. Research on habitat use is essential for understanding population ecology. To investigate the home range and movement patterns we studied a population which occupies an enclosed area of 30 ha in northeastern Algeria. Studies of movement showed that home ranges were substantially smaller than in Spain. This difference was due to the high trophic availability with significant richness in plants which make part of the diet of the tortoise. The home range varied from 0.287 ha in males to 0.354 ha for females; there was no sexual difference. The males are the most active with a distance of 3.79 m/d. Females and juveniles are respectively about 2.25 m/d and 2.11 m/d. The distance moved each day do not vary significantly by sex and ages. Results from this study are important for establishing conservation strategies for this vulnerable species.

scholarly journals Revisiting reptile home ranges: moving beyond traditional estimators with dynamic Brownian Bridge Movement Models

2020 ◽  
Author(s):  
Inês Silva ◽  
Matt Crane ◽  
Benjamin Michael Marshall ◽  
Colin Thomas Strine
Keyword(s):  
Home Range ◽  
Animal Movement ◽  
Brownian Bridge ◽  
Movement Patterns ◽  
Estimation Methods ◽  
Home Ranges ◽  
Telemetry Data ◽  
Range Estimation ◽  
Ambush Predator ◽  
Movement Models

AbstractAnimal movement, expressed through home ranges, can offer insights into spatial and habitat requirements. However, home range estimation methods vary, directly impacting conclusions. Recent technological advances in animal tracking (GPS and satellite tags), have enabled new methods for home range estimation, but so far have primarily targeted mammal and avian movement patterns. Most reptile home range studies only make use of two older estimation methods: Minimum Convex Polygons (MCP) and Kernel Density Estimators (KDE), particularly with the Least Squares Cross Validation (LSCV) and reference (href) bandwidth selection algorithms. The unique characteristics of reptile movement patterns (e.g. low movement frequency, long stop-over periods), prompt an investigation into whether newer movement-based methods –such as dynamic Brownian Bridge Movement Models (dBBMMs)– are applicable to Very High Frequency (VHF) radio-telemetry tracking data. To assess home range estimation methods for reptile telemetry data, we simulated animal movement data for three archetypical reptile species: a highly mobile active hunter, an ambush predator with long-distance moves and long-term sheltering periods, and an ambush predator with short-distance moves and short-term sheltering periods. We compared traditionally used home range estimators, MCP and KDE, with dBBMMs, across eight feasible VHF field sampling regimes for reptiles, varying from one data point every four daylight hours, to once per month. Although originally designed for GPS tracking studies, we found that dBBMMs outperformed MCPs and KDE href across all tracking regimes, with only KDE LSCV performing comparably at some higher-frequency sampling regimes. The performance of the LSCV algorithm significantly declined with lower-tracking-frequency regimes, whereas dBBMMs error rates remained more stable. We recommend dBBMMs as a viable alternative to MCP and KDE methods for reptile VHF telemetry data: it works under contemporary tracking protocols and provides more stable estimates, improving comparisons across regimes, individuals and species.

scholarly journals Reptiles on the wrong track? Moving beyond traditional estimators with dynamic Brownian Bridge Movement Models

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Inês Silva ◽  
Matt Crane ◽  
Benjamin Michael Marshall ◽  
Colin Thomas Strine
Keyword(s):  
Home Range ◽  
High Frequency ◽  
Brownian Bridge ◽  
Space Use ◽  
Estimation Methods ◽  
Tracking Data ◽  
Movement Models ◽  
Frequency Sampling ◽  
Research Questions

Abstract Background Animal movement expressed through home ranges or space-use can offer insights into spatial and habitat requirements. However, different classes of estimation methods are currently instinctively applied to answer home range, space-use or movement-based research questions regardless of their widely varying outputs, directly impacting conclusions. Recent technological advances in animal tracking (GPS and satellite tags), have enabled new methods to quantify animal space-use and movement pathways, but so far have primarily targeted mammal and avian species. Methods Most reptile spatial ecology studies only make use of two older home range estimation methods: Minimum Convex Polygons (MCP) and Kernel Density Estimators (KDE), particularly with the Least Squares Cross Validation (LSCV) and reference (href) bandwidth selection algorithms. These methods are frequently applied to answer space-use and movement-based questions. Reptile movement patterns are unique (e.g., low movement frequency, long stop-over periods), prompting investigation into whether newer movement-based methods –such as dynamic Brownian Bridge Movement Models (dBBMMs)– apply to Very High Frequency (VHF) radio-telemetry tracking data. We simulated movement data for three archetypical reptile species: a highly mobile active hunter, an ambush predator with long-distance moves and long-term sheltering periods, and an ambush predator with short-distance moves and short-term sheltering periods. We compared traditionally used estimators, MCP and KDE, with dBBMMs, across eight feasible VHF field sampling regimes for reptiles, varying from one data point every four daylight hours, to once per month. Results Although originally designed for GPS tracking studies, dBBMMs outperformed MCPs and KDE href across all tracking regimes in accurately revealing movement pathways, with only KDE LSCV performing comparably at some higher frequency sampling regimes. However, the LSCV algorithm failed to converge with these high-frequency regimes due to high site fidelity, and was unstable across sampling regimes, making its use problematic for species exhibiting long-term sheltering behaviours. We found that dBBMMs minimized the effect of individual variation, maintained low error rates balanced between omission (false negative) and commission (false positive), and performed comparatively well even under low frequency sampling regimes (e.g., once a month). Conclusions We recommend dBBMMs as a valuable alternative to MCP and KDE methods for reptile VHF telemetry data, for research questions associated with space-use and movement behaviours within the study period: they work under contemporary tracking protocols and provide more stable estimates. We demonstrate for the first time that dBBMMs can be applied confidently to low-resolution tracking data, while improving comparisons across regimes, individuals, and species.

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