References of "Savini, Tommaso"
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See detailToward a better understanding of habituation process to human observer: A statistical approach in Macaca leonina (Primates: Cercopithecidea)
Gazagne, Eva ULiege; Hambuckers, Alain ULiege; Savini, Tommaso ULiege et al

in Raffles Bulletin of Zoology (2020), 68(2020), 735-749

Habituation allows an observer to closely approach and follow free-ranging animals, as they no longer respond to the observer presence (e.g., through flight, avoidance, display, curiosity). While ... [more ▼]

Habituation allows an observer to closely approach and follow free-ranging animals, as they no longer respond to the observer presence (e.g., through flight, avoidance, display, curiosity). While habituation is implicitly acknowledged as a necessary step before any direct observational studies of primates, there is very little published data on the subject. The aim of this study is to analyse the habituation process over time (17 months) in a wildfeeding troop of northern pigtailed macaques (Macaca leonina) inhabiting a degraded forest fragment of the Sakaerat Biosphere Reserve, Thailand. Based on the number of encounters, contact duration with the studied troop, and behavioural responses to the observer recorded ad libitum and via scan sampling, we found statistical evidence of habituation progress over five stages: early, minimal, partial, advanced, and full. The complete habituation process took nearly 13 months. Factors such as the macaques’ limited experience of human contact, semi-terrestriality, large ranging patterns, fission-fusion dynamics, unpredictable resource use, as well as reduced native fruit availability in this degraded forest fragment may explain the length of the process. It was only possible to collect ranging and behavioural data from the partial habituation stage, although these data were biased toward adult males and sub-adults, while overestimating movement behaviour over inactivity and social behaviours. Our results highlight the importance of analysing behavioural data of fully habituated groups of primates to limit biases of observer presence, and also of not underestimating the habituation process length. This study provides novel information on the habituation process in macaques and proposes an effective methodology to analyse the habituation process across a wide range of primate species. [less ▲]

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See detailWhen Northern Pigtailed Macaques (Macaca leonina) Cannot Select for Ideal Sleeping Sites in a Degraded Habitat
Gazagne, Eva ULiege; Savini, Tommaso ULiege; Ngoprasert, Dusit et al

in International Journal of Primatology (2020), 41(4), 614-633

Primates must select sleeping sites carefully to maximize fitness. In habitats with diminished quality and availability of resources, sleeping site selection becomes an even more crucial aspect of primate ... [more ▼]

Primates must select sleeping sites carefully to maximize fitness. In habitats with diminished quality and availability of resources, sleeping site selection becomes an even more crucial aspect of primate survival. We investigated sleeping site selection patterns in northern pigtailed macaques (Macaca leonina) living in a degraded habitat by testing the hypotheses of random selection, predation avoidance, and food proximity. We followed a group of northern pigtailed macaques in Sakaerat Biosphere Reserve, northeastern Thailand, over 14 months between February 2017 and October 2018. We identified 107 total sleeping sites and analyzed the forest structure at 50 sleeping sites and 50 randomly selected available sites.While the rate of reuse was low and random (N = 15), with sleeping sites characterized by a low availability of large and tall trees, the selection pattern was not random, with sleeping sites occurring more often in familiar areas (i.e., high site fidelity), and those with a greater number of stems and a higher canopy. These sleeping site characteristics were likely selected to decrease detection by predators and facilitate macaque escape in case of attack, supporting the predator avoidance hypothesis. However, food proximity also played a key role in sleeping site selection in this degraded habitat. Macaques often slept within, or close to, their first/last feeding site and selected their sleeping sites following food distribution, presumably to maximize energy intake. Our results present a new impact of habitat degradation on sleeping site selection in large primate groups: the use of a high number of sleeping sites in order to cope with low availability and scattered distribution of fruit resources. [less ▲]

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See detailNorthern pigtailed macaques rely on old growth plantations to offset low fruit availability in a degraded forest fragment
Gazagne, Eva ULiege; José‐Domínguez, Juan Manuel; Huynen, Marie-Claude ULiege et al

in American Journal of Primatology (2020)

Space‐use and foraging strategies are important facets to consider in regard to the ecology and conservation of primates. For this study, we documented movement, ranging, and foraging patterns of northern ... [more ▼]

Space‐use and foraging strategies are important facets to consider in regard to the ecology and conservation of primates. For this study, we documented movement, ranging, and foraging patterns of northern pigtailed macaques (Macaca leonina) for 14 months in a degraded habitat with old growth Acacia and Eucalyptus plantations at the Sakaerat Biosphere Reserve in northeastern Thailand. We used hidden Markov models and characteristic hull polygons to analyze these patterns in regard to fruit availability. Macaques' home range (HR) was 599 ha and spanned through a natural dry‐evergreen forest (DEF), and plantation forest. Our results showed that active foraging increased with higher fruit availability in DEF. Macaques changed to a less continuous behavioral state during periods of lower fruit availability in DEF, repeatedly moving from foraging to transiting behavior, while extending their HR further into plantation forest and surrounding edge areas. Concomitantly, macaques shifted their diet from fleshy to dry fruit such as the introduced Acacia species. Our results showed that the diet and movement ecology adaptations of northern pigtailed macaques were largely dependent on availability of native fruits, and reflected a “high‐cost, high‐yield” foraging strategy when fresh food was scarce and dry fruit was available in plantation forest. Conversely, wild‐feeding northern pigtailed macaque populations inhabiting pristine habitat approached a “low‐cost, low‐yield” foraging strategy. Our results outline the effects of habitat degradation on foraging strategies and show how a flexible species can cope with its nutritional requirements. [less ▲]

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See detailWhen pigtailed macaques cannot select for optimal sleeping sites in degraded habitat
Gazagne, Eva ULiege; Savini, Tommaso ULiege; Ngoprasert, Dusit et al

Conference (2019, October 10)

Primates spend half of their lives in sleeping sites and should select them carefully to maximize fitness. Sleeping site selection in degraded habitat, with reduced availability and quality of resources ... [more ▼]

Primates spend half of their lives in sleeping sites and should select them carefully to maximize fitness. Sleeping site selection in degraded habitat, with reduced availability and quality of resources, is therefore likely to play a leading role in primates’ survival. We aimed to assess the impact of habitat degradation on sleeping site selection patterns in a troop of northern pigtailed macaques, using 3 non-mutually exclusive hypotheses: null hypothesis of random selection, predation avoidance, and food proximity. We identified 107 sleeping sites with only 15 reused sites selected at random in the Sakaerat Biosphere Reserve, northeastern Thailand. After analyzing forest structure at sleeping sites and random sites, we found a general low availability of large and tall trees. Our results show that macaques did not select sleeping sites at random; probability of site selection increased in familiar areas with a high number of stems and with emergent trees. Following the predator avoidance hypothesis, these characteristics are likely to facilitate macaques escape in case of predator attack and also to decrease predator detection at their sleeping sites. Additionally, the food proximity hypothesis seems to be the leading strategy in explaining sleeping sites selection of this degraded habitat. Macaques multiplied their sleeping sites following food distribution, and slept inside or in close proximity to their feeding area, which is likely to maximize their energy intake. Our results highlight the impact habitat degradation may have on sleeping site selection in a flexible species. [less ▲]

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See detailFaire face à une faible disponibilité en fruits dans un habitat dégradé : rôle des plantations chez les macaques à queue de cochon (Macaca leonina) en Thaïlande.
Gazagne, Eva ULiege; José Domínguez, Juan Manuel; Huynen, Marie-Claude ULiege et al

Conference (2019, October 04)

Etudier les facteurs impactant l’utilisation de l’habitat ainsi que les stratégies de recherche alimentaire chez les primates résidents dans des habitats dégradés, est indispensable pour pouvoir mettre en ... [more ▼]

Etudier les facteurs impactant l’utilisation de l’habitat ainsi que les stratégies de recherche alimentaire chez les primates résidents dans des habitats dégradés, est indispensable pour pouvoir mettre en place des stratégies de conservation efficaces. Nous avons étudié l’écologie du mouvement, le domaine vital et les stratégies de recherche alimentaire pendant 14 mois, d’une troupe de macaques à queue-de-cochon du nord (Macaca leonina) de 141± 10 individus dans le fragment forestier dégradé de la réserve de biosphère Sakaerat, située au Nord-Ouest de la Thaïlande. Nous avons analysé ces objectifs en utilisant les méthodes récentes suivantes en fonction de la disponibilité en fruit : les modèles d’Hidden Markov et les polygones caractéristiques de Hull. Nos résultats montrent que la troupe étudiée a un domaine vital total de 599 ha qui couvre la Forêt native Sèche Sempervirente (FSS) et de vieilles plantations d’acacias et d’eucalyptus. Lors des périodes de forte disponibilité en fruits natifs, les macaques recherchent activement de la nourriture à l’intérieur de la FSS (i.e. mouvements lents et variables). A l’inverse, lors des périodes de faibles disponibilités en fruits natifs, les macaques passent plus fréquemment d’un état de recherche alimentaire à un état de transit (i.e. mouvements rapides et orientés). Ils élargissent leurs déplacements aux plantations et zone lisières avec une plus faible fidélité au site quotidienne, bien que les domaines vitaux et trajet parcourus journaliers ne soient pas significativement plus grands. En revanche, les macaques adaptent leur régime alimentaire en consommant significativement plus de fruits secs exotiques comme les graines d’acacia. En combinant pour la première fois de nouvelles analyses sur l’écologie du mouvement et le domaine vital, notre étude montre que les macaques à queue-de-cochon adaptent la dynamique de leur mouvement, leur profil de déplacement ainsi que leur régime alimentaire en fonction de la disponibilité en fruit natif. Ces patrons indiquent que les macaques consomment les ressources prédictibles des plantations et ont tendance à suivre la stratégie de maximisation de l’énergie pour faire face à de faibles disponibilités alimentaires. Cette stratégie énergétique est différente de celle utilisé par leurs congénères habitant la forêt pristine du parc national de Khao Yai située près de Sakaerat, qui ont tendance à minimiser leurs dépenses énergétiques lors de faibles disponibilités en fruit, en diminuant leur domaine vitaux et déplacement quotidiens. Ces résultats approfondissent les connaissances sur l’écologie de cette espèce vulnérable et peu connue, et révèlent un des effets potentiels de la dégradation de l’habitat : la modification des stratégies énergétiques chez les macaques. [less ▲]

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See detailImpact of habitat degradation in northern pigtailed macaques (Macaca leonina) sleeping site selection pattern
Gazagne, Eva ULiege; Savini, Tommaso ULiege; Crane, Matt et al

Conference (2019, June 24)

Primates spend half of their lives at sleeping sites and should select them carefully. Macaques usually use about thirty sleeping sites and their selection respond primarily to predation avoidance. We ... [more ▼]

Primates spend half of their lives at sleeping sites and should select them carefully. Macaques usually use about thirty sleeping sites and their selection respond primarily to predation avoidance. We studied a northern pigtailed macaques troop sleeping sites selection pattern in a degraded forest fragment, the Sakaerat Biosphere Reserve in Thailand. We identified 107 sleeping sites with only 15 reused sites selected at random. Using resource selection function, we found that macaques sleeping site selection is best explained by proximity to feeding areas. Preliminary study of habitat characteristic suggests that there is no structural difference between selected and available sleeping trees in the troop home range. In degraded habitat where forest structure does not offer optimal sleeping trees against predators and with scattered fruit tree distribution, macaques seem to favor strategy based on food resources proximity. These results highlight impact of habitat degradation may have on sleeping site selection in a flexible species. [less ▲]

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See detailForaging strategies underlying bird egg predation by macaques: A study using artificial nests
Kaisin, Olivier ULiege; Gazagne, Eva ULiege; Savini, Tommaso ULiege et al

in American Journal of Primatology (2018), 80(11),

Bird egg predation is widespread in non-human primates. Although nest predation is often described as opportunistic, little is known about foraging strategies and nest detection in primates. Since it is ... [more ▼]

Bird egg predation is widespread in non-human primates. Although nest predation is often described as opportunistic, little is known about foraging strategies and nest detection in primates. Since it is the prevalent cause of nest failure in the tropics, birds select nest sites within specific microhabitats and use different nest types to increase nesting success. Identifying the nests targeted by the northern pigtailed macaques (Macaca leonina), an omnivorous cercopithecine species, and known nest predator, will shine light on nest foraging strategies in primates. The aim of this research was to reveal if nest predation is a selective or opportunistic feeding behavior. We studied, using artificial nests and camera traps, the influence of nest type (open-cup vs. cavity), microhabitat (i.e., understory density, canopy cover, canopy height, ground cover, and presence vs. absence of thorns and lianas), and nest height, on nest predation by a troop of northern pigtailed macaques in the Sakaerat Biosphere Reserve (Thailand), a degraded environment. In our study, macaque predation on artificial nests was high; out of the200nests thatwereset up, 112were plunderedbymacaques. Althoughpredation ratesdecreasedwithnest height,nest type,andmicrohabitathadnosignificant effecton predation by macaques. Nest detectability and accessibility did not affect predation rates. Macaques actively searched for nests in different microhabitats, suggesting that nest predation by this primate might be considered a selective feeding behavior in this degraded habitat. Consequently, nest predation by this primate might have important conservation implications on the population dynamics of forest-dwelling bird species. Behavior observation methods, such as instantaneous scan sampling, may underesti- mate nest predation by primates, a furtive and cryptic behavior. [less ▲]

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See detailSurviving in a degraded forest environment: foraging strategies and space use of northern pigtailed macaques (Macaca leonina) in Sakaerat Biosphere reserve, Northeastern Thailand
Gazagne, Eva ULiege; Hambuckers, Alain ULiege; Savini, Tommaso ULiege et al

Conference (2018, July 05)

Space-use patterns and foraging strategy in degraded habitat are crucial to understand the ecology, adaptation, and conservation of primates. However, detailed ranging and behavioral data are scarce for ... [more ▼]

Space-use patterns and foraging strategy in degraded habitat are crucial to understand the ecology, adaptation, and conservation of primates. However, detailed ranging and behavioral data are scarce for many species, especially from Southeast Asia. We aimed to determine the northern pigtailed macaques (Macaca leonina) dietary, ranging, and habitat use patterns in the Sakaerat Biosphere reserve in Northeastern Thailand, a degraded habitat with ancient plantations and sub-optimal resources availability. We studied these patterns for eleven months in regard of fruit availability in a wild troop of these macaques. We used Characteristic Hull Polygons (CHP) combined with spatial statistics to estimate home ranges and core areas. We ran a monthly phenology survey to measure fruit availability over the study period. We predicted that macaques would increase their ranging during low fruit abundance to gather enough food (i.e. energy-maximizing strategy) and would use more intensively plantation and edge areas. We found a total home range of 535.5 ha and an average core area of 219.3 ha, with an average daily path length of 2,226 m. During high fruit abundance, macaques spent more time around fruit-tree species in the dry evergreen forest. During low fruit abundance, they extended their home range to plantations forest and edge areas. Fruit consumption was positively correlated to fruit abundance and there was a clear shift from flesh and pulp to dry fruit during low fruit abundance season. While the portion of home range used decreased in period of high fruit availability, daily path length and core area size did not change. Overall, as predicted, our preliminary data shows that the study troop used an energy-maximizing strategy and was able to expand the range of resources consumed in fruit scarcity period. Conversely, a study done using the same method on the same species in the nearby pristine Khao Yai National park found an energy-minimizing strategy, that is, decreased ranging area in periods of food scarcity. In conclusion, as in previous studies, our results show indeed that northern pigtailed macaques adapt their diet, monthly range and habitat use according to food abundance. However, they indicate they adapt it in an opposite way. In a degraded forest environment, the northern pigtailed macaques seem to change their survival strategy by increasing their range in periods of food scarcity to seek additional resources. These findings pose the question of substantial modification of ecological strategies by species constrained by human alteration of their habitat. [less ▲]

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See detailFood provioning influences ranging patterns in northern pigtailed macaques (Macaca leonina)
Huynen, Marie-Claude ULiege; Savini, Tommaso ULiege; Asensio, Norberto et al

in International Journal of Primatology (2015, January)

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See detailExploring the multiple functions of sleeping sites in Northern Pigtail macaques (Macaca leonina)
Jose Dominguez, Juan Manuel; Asensio, Norberto; Garcia Garcia, Carmen J et al

in International Journal of Primatology (2015), 36(4), 948-966

the seasonal variation, maximizing daily activities. Overall, predator avoidance and food efficiency were the main factors influencing the selection of sleeping sites. Our observations differ from those ... [more ▼]

the seasonal variation, maximizing daily activities. Overall, predator avoidance and food efficiency were the main factors influencing the selection of sleeping sites. Our observations differ from those found in a semiprovisioned group inhabiting the same Abstract Sleeping site selection in nonhuman primates may respond to various eco- logical factors, including predation avoidance, range defense, and foraging efficiency. We studied the sleeping sites used by a group of northern pigtailed macaques on 124 nights to test these hypotheses. The macaques used 57 different sleeping sites, of which 33 were used only once. They rarely used the same site on consecutive nights. These selection patterns are consistent with an antipredatory function, but may also be related to an antipathogenic strategy. Sleeping sites were located principally in the most heavily used areas of the home range and were generally away from areas of intergroup encounters. However, some of the most heavily used sleeping sites were in the area where intergroup encounters occurred, and intergroup encounters at sleeping sites always showed high levels of agonism, indicating possible intergroup competition over sleeping sites. On 77 % of nights, the study group selected the sleeping site nearest to either the last feeding area that day or to the first feeding area used the next morning, suggesting a foraging efficiency strategy. The mean distances from the sleeping site to the last and first feeding area were 227 m and 127 m, respectively, suggesting a multiple central place foraging strategy. The macaques entered sleeping sites a mean of 27 min before sunset and left 24 min after sunrise, and these times varied in line withstudy site, which used fewer sleeping sites and reused them much more often. This difference highlights the impact anthropogenic activities may have on sleeping site selection and the flexibility of sleeping patterns in a single species. Such flexibility may have helped the tree-to-ground evolutionary transition of sleep habits in primates [less ▲]

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See detailThe value of disturbance-tolerant cercopithecine monkeys as seed dispersers in degraded habitats
Albert, Aurélie; McConkey, Kim; Savini, Tommaso ULiege et al

in Biological Conservation (2014), 170

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See detailDifferent spatial and territorial patterns between Northern pigtail macaques and white-handed gibbons using the characteristic Hull polygon method
Dominguez, José Juan Manuel; Asensio, N; Huynen, Marie-Claude ULiege et al

Conference (2013, March)

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See detailThe role of Macaca spp (primates Cercopithecidae) in seed dispersal networks
Albert, Aurélie; Savini, Tommaso ULiege; Huynen, Marie-Claude ULiege

in Raffles Bulletin of Zoology (2013), 61

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See detailA study on the ecology of northern pigtail macaque (Amcaca nemestrina) in Khao Yai National PArk
Savini, Tommaso ULiege; albert, aurélie; José Dominguez, Juan Manuel et al

Conference (2012, August)

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See detailHome range size and daily path length in a wild troop of northern pigtailed macaques (Macaca leonina): preliminary results
Jose Dominguez, Juan Manuel; Albert, aurélie; Garcia, CJ et al

Conference (2012, March)

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See detailSeasonal variations of ranging pattern in pigtailed macaques: influence of wild and human resources
Albert, Aurélie ULiege; Savini, Tommaso ULiege; Huynen, Marie-Claude ULiege

Conference (2011, September)

Numerous studies have highlighted the influence of food availability on primate behaviour. Our research aims at understanding the ranging pattern of a troop of northern pigtailed macaques (Macaca leonina ... [more ▼]

Numerous studies have highlighted the influence of food availability on primate behaviour. Our research aims at understanding the ranging pattern of a troop of northern pigtailed macaques (Macaca leonina) living around the visitor center of the Khao Yai National Park, Thailand. The frugivorous pigtailed macaques are supposed to adapt their ranging pattern to the spatio-temporal distribution of fruiting trees. However, the presence of humans, and thus, of human food, may also have an impact on their home range size and location. We followed the troop during 12 months and recorded its diet and progression within the home range (GPS points every 30 minutes). On monthly kernels defining the home range surface, we superimposed a grid of 110x110 m cells. We analysed the spatio-temporal distribution of fruiting trees in botanical transects and converted it into a food abundance index (FAI). Given their semi-terrestriality decreasing travel costs, we predicted that macaques should increase their range during the period of low fruit abundance to gather a sufficient amount of high-quality food (fruits). To the contrary, our results showed that the size of the troop’s home range decreased during fruit scarcity (dry season). The diet analysis showed that during this period, macaques used human food, a high-quality resource, as fallback food which concentration around human settlements made the long travel no more necessary. Alternately, in period of fruit abundance, a correlation between the FAI and the number of GPS points from macaques for each home range cell showed that macaques spent more time in places with a higher abundance of some fruit species, in particular some considered as important in their diet. Finally, in this peculiar situation of macaques living close to human managed areas, both wild and human resources’ spatio-temporal distribution influence the size and location of the troop’s home range [less ▲]

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See detailSleeping Site Selection and Presleep Behavior in Wild Pigtailed Macaques
Albert, Aurélie ULiege; Savini, Tommaso ULiege; Huynen, Marie-Claude ULiege

in American Journal of Primatology (2011), 73

Several factors are likely to control sleeping site selection and presleep behavior in nonhuman primates, including predation risk and location of food resources. We examined the effects of these factors ... [more ▼]

Several factors are likely to control sleeping site selection and presleep behavior in nonhuman primates, including predation risk and location of food resources. We examined the effects of these factors on the sleeping behavior of northern pigtailed macaques (Macaca leonina). While following a troop living in the surroundings of the Visitor Center of Khao Yai National Park (Thailand), we recorded the physical characteristics and location of each sleeping site, tree, the individuals’ place in the tree, posture, and behavior. We collected data for 154 nights between April 2009 and November 2010. The monkeys preferred tall sleeping trees (20.97SD 4.9 m) and high sleeping places (15.87SD 4.3 m), which may be an antipredator strategy. The choice of sleeping trees close to the last (146.77SD 167.9 m) or to the first (150.47SD 113.0 m) feeding tree of the day may save energy and decrease predation risk when monkeys are searching for food. Similarly, the choice of sleeping sites close to human settlements eases the access to human food during periods of fruit scarcity. Finally, the temporal pattern of use of sleeping sites, with a preference for four of the sleeping sites but few reuses during consecutive nights, may be a tradeoff between the need to have several sleeping sites (decreasing detection by predators and travel costs to feeding sites), and the need to sleep in well-known sites (guaranteeing a faster escape in case of predator attack). [less ▲]

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