Estimating Site Occupancy and Detection Probability Parameters for Meso- And Large Mammals in a Coastal Ecosystem

2006 ◽  
Vol 70 (6) ◽  
pp. 1625-1633 ◽  
Author(s):  
ALLAN F. O'CONNELL ◽  
NEIL W. TALANCY ◽  
LARISSA L. BAILEY ◽  
JOHN R. SAUER ◽  
ROBERT COOK ◽  
...  
Keyword(s):  
Detection Probability ◽  
Site Occupancy ◽  
Coastal Ecosystem ◽  
Large Mammals

Effects of commercial thinning on site occupancy and habitat use by spruce grouse in boreal Quebec

2011 ◽  
Vol 41 (3) ◽  
pp. 501-508 ◽  
Author(s):  
Ambroise Lycke ◽  
Louis Imbeau ◽  
Pierre Drapeau
Keyword(s):  
Habitat Use ◽  
Boreal Forest ◽  
Breeding Season ◽  
Vegetation Cover ◽  
Forest Cover ◽  
Site Occupancy ◽  
Lower Proportion ◽  
Large Mammals ◽  
Dense Vegetation ◽  
Commercial Thinning

Partial cuts are increasingly proposed to maintain habitats for species negatively affected by clearcutting, even if their benefits on nonpasserine birds and large mammals are still poorly documented. Our main objective was to evaluate effects of commercial thinning (CT) on spruce grouse ( Falcipennis canadensis L.), a game bird of the boreal forest. Because this species is known to be associated with a dense vegetation cover, we hypothesized that habitat use would be lower in treated sites. In spring 2006, we evaluated site occupancy in 94 forest stands (50 CT and 44 uncut stands) in Quebec by visiting each on three occasions during the breeding season (March–May). Additionally, during the molting period (May–July), we used radiotelemetry to monitor habitat use by 19 males. As compared with uncut stands, results show that a lower proportion of CTs were used in spring (39% versus 60%, after accounting for detection). During the molting period, CTs were also used less than expected according to their availability. The significant reduction of lateral and vertical forest cover in CT may explain these results. We conclude that even if CT is perceived beneficial for wildlife, it does not completely fulfill the needs of species associated with dense understory vegetation, such as spruce grouse.

scholarly journals Designing an occupancy framework to monitor an endemic rainforest duck: Methodological and modelling considerations

2020 ◽  
Author(s):  
Shah Nawaz Jelil ◽  
Murchana Parasar ◽  
Laura Cancino ◽  
Kimberly Cook
Keyword(s):  
Detection Probability ◽  
Site Occupancy ◽  
Optimal Number ◽  
Occupancy Models ◽  
Occupancy Detection ◽  
Habitat Factors ◽  
Long Term Ecological Research ◽  
Species Occupancy ◽  
Future Population

AbstractUnderstanding species trend, decline or growth, is vital to further conservation efforts. Species-habitat relationship studies are equally important for conservation as it helps in understanding the habitat a particular species depends upon, i.e. habitat conservation. However, rare and endemic species are inherently difficult to study and occupancy models are especially useful in such cases. We conducted the first detection, non-detection survey for the white winged duck in Dehing Patkai Wildlife Sanctuary, India to assess site occupancy and test habitat factors that explain its occupancy. We found that white winged duck occupancy was low (0.27 ± 0.21 SE) and detection probability was 0.44 ± 0.30 SE. We found that increasing tree richness and decreasing elevation increased species occupancy. Detection probability was influenced by our effort in that detection increased with increasing number of survey hours. Using two standard approaches, we estimated the optimal number of sites and replicate surveys for future occupancy studies. We further present considerations for future surveys. Considering the sporadic and fragmented information available, we recommend long-term ecological research to better understand the present and future population trends of the species.

scholarly journals Estimating detection probability and site occupancy of Leiolepis guentherpetersi in the coastal sandy areas of Phu Loc district, Thua Thien Hue province

2018 ◽  
Vol 40 (4) ◽  
Author(s):  
Cao Thi Thanh Nguyen ◽  
Ngo Van Binh ◽  
Ngo Dac Chung
Keyword(s):  
Environmental Factors ◽  
Detection Probability ◽  
Site Occupancy ◽  
Weather Conditions ◽  
Coastal Areas ◽  
Available Information

The Peter’s Butterfly Lizard (Leiolepis guentherpetersi) is endemic to Vietnam. However, there is no available information related to detection probability and site occupancy of this species so far. Nine surveys were conducted at 50 plots in the coastal areas of Phu Loc district from September to December 2017 in order to detect the presence of Leiolepis guentherpetersi. Our results showed that the detection probability of L. guentherpetersi, when combined with environmental factors, was 0.383, which was higher than the naive detection probability of 0.34. The total AIC weight of the near sea ecosystem was 85.9% while the total AIC weight of the ecosystem far from the sea was only 13.5%. The AIC weight of weather conditions was 99.4% while the total AIC weight of temperature was 62.3% and the total AIC weight of humidity was 27.2%. These results indicated that the probability of detecting L. guentherpetersi influenced by both site covariates (near the sea or far from the sea) and sample covariates (temperature, humidity, and rainfall). In there, the near sea ecosystem is the best habitat for L. guentherpetersi and rainfall is sample covariates that had the greatest influence on detection probability and site occupancy of this species. 

scholarly journals Okupansi Kukang Jawa (Nycticebus javanicus E. Geoffroy 1812) di Hutan Tropis Dataran Rendah di Kemuning, Bejen, Temanggung, Jawa Tengah

2019 ◽  
Vol 13 (1) ◽  
pp. 15 ◽  
Author(s):  
Mahfut Sodik ◽  
Satyawan Pudyatmoko ◽  
Pujo Semedi Hargo Yuwono
Keyword(s):  
Detection Probability ◽  
Negative Impact ◽  
Site Occupancy ◽  
Water Source ◽  
Critically Endangered ◽  
Primate Species ◽  
Slow Loris ◽  
Occupancy Model ◽  
Central Java ◽  
Site Use

Faktor kehilangan/berkurangnya habitat, dan fragmentasi habitat dapat memberikan dampak buruk terhadap kukang Jawa (Nycticebus javanicus), satwa primata nokturnal yang tergolong dalam kategori Critically Endangered. Kukang Jawa yang hidup di hutan yang terfragmentasi merasakan dampak negatif dari faktor- faktor tersebut dan hal tersebut juga dapat memengaruhi okupansi dalam sebuah kawasan. Penelitian ini bertujuan untuk mengetahui faktor-faktor yang memengaruhi okupansi habitat oleh kukang Jawa di hutan dataran rendah yang terfragmentasi di Kemuning, Temanggung, Jawa Tengah, Indonesia. Untuk mem­perkirakan proporsi penggunaan wilayah, probabilitas detek­si (detection probability) dan faktor – faktor yang berpengaruh terhadap okupansi habitat oleh kukang Jawa, kami menggunakan occupancy model of a single-season. Sebanyak 5 kali ulangan survei malam pada tahun 2017 digunakan sebagai data pokok di dalam model okupansi. Metode pengambilan data lingkungan dan data anthropogenic menggunakan observasi lapangan dan interview dengan masyarakat lokal. Kami membagi lokasi penelitian menjadi 141 grid dengan ukuran 200 m x 200 m (4 ha) sebagai acuan dalam survei malam dengan jalur. Data kovariat lingkungan yang diukur adalah jarak dari jalan, jarak dari tepi hutan, jarak dari pemukiman, jarak dari sumber air, ketinggian tempat, dan kemiringan lahan. Hasil penelitian menunjukan bahwa kukang Jawa menghuni habitat sekitar 23,2% dari keseluruhan areal di hutan Kemuning. Jarak dari jalan dan jarak dari sumber air (sungai) berkorelasi positif terhadap tingkat hunian, sedang jarak dari pemukiman berkorelasi negatif terhadap tingkat hunian dari kukang Jawa. Data dan informasi kuantitatif yang dihasilkan dari penelitian ini penting untuk mengetahui kebutuhan sumber daya jangka panjang populasi kukang Jawa khususnya di hutan Kemuning. Selanjutnya diharapkan pemerintah Indonesia atau stakeholder terkait dapat melakukan upaya konservasi dan rencana strategi pengelolaan spesies kukang Jawa dengan baik khususnya di hutan dataran rendah yang terfragmentasi.Occupancy of Javan Slow Loris (Nyticebus javanicus E. Geoffroy 1812) in Kemuning Tropical Low Land Forest, Bejen, Temanggung, Central Java Abstract Habitat loss and landscape fragmentation have a negative impact on the Javan slow loris (Nycticebus javanicus), a Critically Endangered nocturnal primate species. Slow lorises in remaining forest fragments might be suffered and affect their occupancy behavior. We aim to investigate the determinant factors for the probability of habitat occupancy by the javan slow loris in Kemuning forest fragment of Temanggung District, Central Java. To estimate the site occupancy rate, detection probability, and the determinant factor of site use by Nycticebus javanicus, we employed the occupancy model of a single-season using night surveys. Five repeated night surveys in 2017 were used as the main basis data for the occupancy model. We used direct observation and interview with locals to collect data on environmental and anthropogenic features. We divided the study area into 141 grids with 200 m x 200 m (4 ha) each which were the basis for the night survey following existing walking paths. The influence of six covariates was assessed to determine of site use by Nycticebus javanicus: distance to road, distance to forest edge, distance to the settlement, distance to water source, altitude, and elevation. The result shows that the probability of site use occupied by Nycticebus javanicus was 23.2% of the total area. Distance to roads and distance to water source have a positive correlation with the probability of site use, whereas the influence of distance to settlements has a negative correlation with the site use of the species. Such quantitative data and information gained in this research are important to know for the long term resource needs of the Nycticebus javanicus, especially in the Kemuning forest. Therefore, the Indonesian Government or related stakeholders can formulate the detail conservation plans of the species, especially in the lowland fragmented tropical forest.

Estimating site occupancy and detectability of an endangered New Zealand lizard, the Otago skink (Oligosoma otagense)

2006 ◽  
Vol 33 (3) ◽  
pp. 193 ◽  
Author(s):  
Catherine M. Roughton ◽  
Philip J. Seddon
Keyword(s):  
New Zealand ◽  
Detection Probability ◽  
Site Occupancy ◽  
Implicit Assumption ◽  
Monitoring Methods ◽  
Analytical Technique ◽  
Robust Estimates ◽  
Simple Index ◽  
Management Interventions ◽  
Reptile Species

There is a need to develop appropriate monitoring methods for cryptic reptile species, such as the endangered New Zealand endemic Otago skink (Oligosoma otagense), that take into account incomplete detectability. A recently developed analytical technique was applied to presence–absence data for Otago skinks to derive robust estimates of both detection probability and site occupancy. The estimated detection probability for Otago skinks was 0.4 (s.e. 0.052), and the estimate of the proportion of the study area occupied by Otago skinks was 0.71 (s.e. 0.11). The data derived from presence–absence surveys in consistently sunny weather, with a standardised scanning and searching technique, provided a good basis for robust estimates of detection probability and of the percentage of area occupied by skinks. This survey technique could be applied to other similarly cryptic reptile species to derive rigorous estimates of site occupancy in order to track changes over time or in response to management interventions. It will be particularly appropriate where precise estimation of absolute abundance is not warranted, or where a simple index of relative abundance may be invalid due to failure of the implicit assumption of constant detectability.

scholarly journals Understanding distribution and occupancy of Himalayan Monal in Uttarkashi district, Uttarakhand

2021 ◽  
Author(s):  
Amira Sharief ◽  
Hemant Singh ◽  
Bheem Dutt Joshi ◽  
Tanoy Mukherjee ◽  
Kailash Chandra ◽  
...  
Keyword(s):  
Detection Probability ◽  
Site Occupancy ◽  
Null Model ◽  
Average Density ◽  
Camera Traps ◽  
Occupancy Probability ◽  
Sign Surveys ◽  
Reserve Forest ◽  
Anthropogenic Threats ◽  
Conservation And Management

AbstractThe Himalayan Monal is a conservation priority species in its entire distribution range. Its population is declining in many areas due to various anthropogenic threats. The information on species distribution and its abundance is lacking in many areas which are vital for conservation and management planning. Hence, through the present study, we have assessed the abundance and occupancy of Himalayan monal in Uttarkashi district (Uttarakhand). We used camera traps and conventional sign surveys for documenting the species during 2018-2019. We installed a total of 69 camera traps (2819 trap nights) and surveyed 54 trails (650 km) which represents entire habitat and topographic variability of the landscape. The occupancy and detection probability was modelled using the habitat variables. The top model showed that occupancy probability of Himalayan monal was positively influenced by the slope (β =27.52 ±16.25) and negatively influenced by Reserve Forest (RF) (β= −8.14 SE ± 4.99). The observed naïve occupancy of Himalayan Monal was 0.69 in the study area, which was slightly lower than the estimated occupancy. However, in the null model, the site occupancy estimated was found to be 0.82±0.08 and with detection probability 0.23±0.03. The overall abundance of monal was estimated about 171.58 ±10.2 in the study area with an average density of 0.62/ km2. The activity pattern analysis indicates that monal remains very active between 6.00 hrs −12.00 hrs and relatively less active during mid-day when humans are most active 11.30 hrs-16.30 hrs. The present study is a first attempt to estimate occupancy and abundance using camera traps as well as sign survey for the species primarily from non-Protected Area (PA). We found that Himalayan monal is abundant outside the PAs, which is a good indication for its long-term viability and also identified areas for conservation and management prioritization in Uttarkashi.

Factors Associated with Detection Probability and Site Occupancy of the Long-Tailed Skink (Eutropis longicaudata) in the Aluoi Area, Central Vietnam

2021 ◽  
Vol 28 (2) ◽  
pp. 67-72
Author(s):  
Chung D. Ngo ◽  
Hai P. Dang ◽  
Nghiep T. Hoang ◽  
Binh Van Ngo
Keyword(s):  
Detection Probability ◽  
Site Occupancy ◽  
Weather Conditions ◽  
Habitat Model ◽  
Occupancy Models ◽  
Lizard Species ◽  
Disturbed Habitat ◽  
Occupancy Probability ◽  
Central Vietnam ◽  
A Site

Lizard species are rarely detected with perfect accuracy, regardless of the method employed. Nondetection of a species at a site does not necessarily mean the species was absent unless the detection probability was 100%. We assessed the influence of site covariates (less disturbed habitat and disturbed habitat) and sample covariates (temperature, humidity, rainfall) on the occupancy of Eutropis longicaudata in the Aluoi area, central Vietnam. Based on detection/nondetection data over nine visits at 40 less disturbed sites and 39 sites with disturbed habitats, the distribution of E. longicaudata was estimated using site occupancy models. From the best model, we estimated a site occupancy probability of 0.595, a 12.05% increase over the naive occupancy of 0.531 at which E. longicaudata skinks were actually observed. The site covariate of the less disturbed habitat was an important determinant of site occupancy, which was not associated with the variable of disturbance habitats. In the combined AIC model weight, p(precipitation), p(temperature), and p(humidity) have 92%, 36%, and 21% of the total, respectively; providing evidence that environmental conditions (especially precipitation) were important sample covariates in modelling detection probabilities of E. longicaudata. In terms of occupancy probability, the combined weight for the ψ(less disturbed habitat) model and the ψ(disturbed habitat) model were 60% and 32%, respectively. Our results substantiate the importance of incorporating detection and occupancy probabilities into studies of habitat relationships and suggest that the less disturbed habitat associated with weather conditions influence the occupancy of E. longicaudata in central Vietnam.

ESTIMATING SITE OCCUPANCY AND SPECIES DETECTION PROBABILITY PARAMETERS FOR TERRESTRIAL SALAMANDERS

2004 ◽  
Vol 14 (3) ◽  
pp. 692-702 ◽  
Author(s):  
Larissa L. Bailey ◽  
Theodore R. Simons ◽  
Kenneth H. Pollock
Keyword(s):  
Detection Probability ◽  
Site Occupancy ◽  
Species Detection

scholarly journals Status assessment of the Endangered snow leopard Panthera uncia and other large mammals in the Kyrgyz Alay, using community knowledge corrected for imperfect detection

Oryx ◽  
2015 ◽  
Vol 50 (2) ◽  
pp. 220-230 ◽  
Author(s):  
Julia Taubmann ◽  
Koustubh Sharma ◽  
Kubanychbek Zhumabai Uulu ◽  
James E. Hines ◽  
Charudutt Mishra
Keyword(s):  
High Probability ◽  
Site Occupancy ◽  
Local Extinction ◽  
Snow Leopard ◽  
Lynx Lynx ◽  
Large Mammals ◽  
Imperfect Detection ◽  
North West ◽  
Snow Leopards ◽  
Panthera Uncia

AbstractThe Endangered snow leopard Panthera uncia occurs in the Central Asian Mountains, which cover c. 2 million km2. Little is known about its status in the Kyrgyz Alay Mountains, a relatively narrow stretch of habitat connecting the southern and northern global ranges of the species. In 2010 we gathered information on current and past (1990, the last year of the Soviet Union) distributions of snow leopards and five sympatric large mammals across 14,000 km2 of the Kyrgyz Alay. We interviewed 95 key informants from local communities. Across 49 400-km2 grid cells we obtained 1,606 and 962 records of species occurrence (site use) in 1990 and 2010, respectively. The data were analysed using the multi-season site occupancy framework to incorporate uncertainty in detection across interviewees and time periods. High probability of use by snow leopards in the past was recorded in > 70% of the Kyrgyz Alay. Between the two sampling periods 39% of sites showed a high probability of local extinction of snow leopard. We also recorded high probability of local extinction of brown bear Ursus arctos (84% of sites) and Marco Polo sheep Ovis ammon polii (47% of sites), mainly in regions used intensively by people. Data indicated a high probability of local colonization by lynx Lynx lynx in 41% of the sites. Although wildlife has declined in areas of central and eastern Alay, regions in the north-west, and the northern and southern fringes appear to retain high conservation value.

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