References of "Bouché, Philippe"
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See detailPreliminary description of the diet of Hippopotamus amphibius L. in Loango National Park (Gabon)
Michez, Adrien ULg; Doucet, Jean-Louis ULg; Dendocker, Nicolas et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(4), 580-583

Due to the paucity of suitable habitat, hippos are very rare in the Congo Bassin. Compared to East-African populations, Central African populations of hippos have been less studied. Information found in ... [more ▼]

Due to the paucity of suitable habitat, hippos are very rare in the Congo Bassin. Compared to East-African populations, Central African populations of hippos have been less studied. Information found in the literature regarding the animal’s basic ecology is limited. This study focuses on the description of the diet of an isolated hippo population in Loango National Park (Gabon), comparing faecal analysis with a reference collection ofherbaceous species from the savannas. The effectiveness of using faecal analysis versus using the floristic description of hippos’ pastures was demonstrated. The most frequent herbaceous species identified in faeces samples were Paspalum vaginatum, Axonopus compressus, Stenotaphrum secundatum (Poaceae) and Desmodium triflorum (Fabaceae). The voluntary consumption of a dicotyledonous species (Desmodium triflorum) is novel for this species. [less ▲]

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See detailAerial surveys using an Unmanned Aerial System (UAS): comparison of different methods for estimating the surface area of sampling strips
Lisein, Jonathan ULg; Linchant, Julie ULg; Lejeune, Philippe ULg et al

in Tropical Conservation Science (2013), 6(4), 506-520

Conservation of natural ecosystems requires regular monitoring of biodiversity, including the estimation of wildlife density. Recently, unmanned aerial systems (UAS) have become more available for ... [more ▼]

Conservation of natural ecosystems requires regular monitoring of biodiversity, including the estimation of wildlife density. Recently, unmanned aerial systems (UAS) have become more available for numerous civilian applications. The use of small drones for wildlife surveys as a surrogate for manned aerial surveys is becoming increasingly attractive and has already been implemented with some success. This raises the question of how to process UAS imagery in order to determine the surface area of sampling strips within an acceptable confidence level. For the purpose of wildlife surveys, the estimation of sampling strip surface area needs to be both accurate and quick, and easy to implement. As GPS and an inertial measurement units are commonly integrated within unmanned aircraft platforms, two methods of direct georeferencing were compared here. On the one hand, we used the image footprint projection (IFP) method, which utilizes collinearity equations on each image individually. On the other hand, the Structure from Motion (SfM) technique was used for block orientation and georeferencing. These two methods were compared on eight sampling strips. An absolute orientation of the strip was determined by indirect georeferencing using ground control points. This absolute orientation was considered as the reference and was used for validating the other two methods. The IFP method was demonstrated to be the most accurate and the easiest to implement. It was also found to be less demanding in terms of image quality and overlap. However, even though a flat landscape is the type most widely encountered in wildlife surveys in Africa, we recommend estimating IFP sensitivity at an accentuation of the relief. [less ▲]

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See detailUsing drones to count the elephants: a new approach of wildlife inventories
Linchant, Julie ULg; Vermeulen, Cédric ULg; Lisein, Jonathan ULg et al

Conference (2013, August 29)

The use of UASs (Unmanned Aerial Systems) in wildlife survey is still recent but the fast development of this technology shows great possibilities and it could soon become an inevitable tool in wildlife ... [more ▼]

The use of UASs (Unmanned Aerial Systems) in wildlife survey is still recent but the fast development of this technology shows great possibilities and it could soon become an inevitable tool in wildlife management. The purpose of this study was to test the feasibility of inventories by UAS to survey large mammals in the Nazinga Game Ranch in the south of Burkina Faso. The Gatewing X100TM equipped with a Ricoh GR III camera was used to test the animal reaction as it passed, and their visibility on the images. A set of more than 7000 images was collected and observations revealed that only elephants (Loxodonta africana) were easily visible while medium and small sized mammals were not. At a height of 100 m the easy observation of elephant allows experts to enumerate them on images and no reaction was recorded as the UAS passed. We therefore implemented an aerial strip sample count along transects used for the annual wildlife foot count. A total of 34 elephants has been recorded on 4 transects, each overflown twice. The elephant density was estimated at 2.47 elephants/km2 with a coefficient of variation (CV%) of 36.10 %. UAS inventory of elephants is promising but improvements need to be done. The main drawback of our UAS was its autonomy. If we wish to replace manned aircraft survey of large areas (about 1000 km of transect per day vs 40 km for our UAS), increased endurance of small UAS is a requirement and the monitoring strategy should be adapted according to the sampling plan. Also, the UAS is as expensive as a second-hand light aircraft. However the logistic and flight implementation are easier, the running costs are lower and its use is safer. With technological evolution making civil UASs more efficient, they will be able to compete with light aircrafts for aerial wildlife surveys. [less ▲]

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See detailUnmanned aerial survey of elephants
Vermeulen, Cédric ULg; Lejeune, Philippe ULg; Lisein, Jonathan ULg et al

in PLoS ONE (2013), 8(2),

The use of a UAS (Unmanned Aircraft System) was tested to survey large mammals in the Nazinga Game Ranch in the south of Burkina Faso. The Gatewing ×100™ equipped with a Ricoh GR III camera was used to ... [more ▼]

The use of a UAS (Unmanned Aircraft System) was tested to survey large mammals in the Nazinga Game Ranch in the south of Burkina Faso. The Gatewing ×100™ equipped with a Ricoh GR III camera was used to test animal reaction as the UAS passed, and visibility on the images. No reaction was recorded as the UAS passed at a height of 100 m. Observations, made on a set of more than 7000 images, revealed that only elephants (Loxodonta africana) were easily visible while medium and small sized mammals were not. The easy observation of elephants allows experts to enumerate them on images acquired at a height of 100 m. We, therefore, implemented an aerial strip sample count along transects used for the annual wildlife foot count. A total of 34 elephants were recorded on 4 transects, each overflown twice. The elephant density was estimated at 2.47 elephants/km2 with a coefficient of variation (CV%) of 36.10%. The main drawback of our UAS was its low autonomy (45 min). Increased endurance of small UAS is required to replace manned aircraft survey of large areas (about 1000 km of transect per day vs 40 km for our UAS). The monitoring strategy should be adapted according to the sampling plan. Also, the UAS is as expensive as a second-hand light aircraft. However the logistic and flight implementation are easier, the running costs are lower and its use is safer. Technological evolution will make civil UAS more efficient, allowing them to compete with light aircraft for aerial wildlife surveys. [less ▲]

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See detailGame species monitoring using road–based distance sampling in association with thermal imagers: a covariate analysis
Morelle, Kevin ULg; Bouché, Philippe; Lehaire, François ULg et al

in Animal Biodiversity and Conservation (2012), 35(2), 253-265

Monitoring of game species populations is necessary to adequately assess culling by hunters in areas where natural large predators are absent. However, game managers have to control several species and ... [more ▼]

Monitoring of game species populations is necessary to adequately assess culling by hunters in areas where natural large predators are absent. However, game managers have to control several species and they often lack of an efficient and convenient survey design method. Monitoring several species at that same time over large areas could thus be cost– and time–effective. We tested the influence of several factors during monitoring of three common game species, (wild boar, roe deer and red fox, using road–based distance sampling in association with thermal imagers. This pilot survey based on 20 night counts in five contrasting sites studied the effect of several covariates (species, thermal imaging, observer, group size, and habitat type) on the detection probabilities. No differences were observed between thermal imagers and group sizes , but we found differences between observers . Expected differences were also observed between species and between habitat type. Our results show that the detectability of low cost thermal imaging equipment is similar to that of more expensive methods, highlighting new possibilities for the use of thermal imagery by game managers. Although adjustments should be made to the study design our findings suggest that large–scale multi–species monitoring could be an efficient method for common game species. [less ▲]

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See detailEstimation des effectifs des populations d’éléphants par la méthode d’inventaire pédestre total au Ranch de Gibier de Nazinga (Burkina Faso)
Ouédraogo, Moumouni.; Delvingt, Willy; Doucet, Jean-Louis ULg et al

in Pachyderm (2009), 45

The low number of observations recorded during a recce using transects often makes it difficult to obtain correct estimations concerning the number of a certain species. This applies to elephants in the ... [more ▼]

The low number of observations recorded during a recce using transects often makes it difficult to obtain correct estimations concerning the number of a certain species. This applies to elephants in the Nazinga Game Ranch, Burkina Faso. In this study, another method was tested, that of the ‘the total foot count’. It has been demonstrated that in the ecological conditions of Nasinga, this method produces accurate estimations. In August 2001 and March 2002, the numbers were 345 and 189 elephants respectively. This method also enables us to more accurately calculate the age and sex structure of the animals, which is another important advantage. [less ▲]

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