Publications of Eva Gazagne
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See detailSeed shadows of northern pigtailed macaques within a degraded forest fragment, Thailand
Gazagne, Eva ULiege; Pitance, Jean-Luc ULiege; Savini, Tommaso ULiege et al

in Revue de Primatologie (2020, December 10), 11

Determining seed shadow (i.e. seed deposition pattern of a plant population) produced by frugivores is difficult to evaluate by direct observations, although of paramount importance to understand their ... [more ▼]

Determining seed shadow (i.e. seed deposition pattern of a plant population) produced by frugivores is difficult to evaluate by direct observations, although of paramount importance to understand their effectiveness as seed dispersal agents in degraded habitat. We developed a modeling approach of seed shadows incorporating field-collected data on a troop of 141 ± 10 individuals of northern pigtailed macaques (Macaca leonina) inhabiting a degraded forest fragment in Thailand, by implementing a mechanistic model of seed deposition with random components. We parameterized the model with macaque feeding behavior (i.e. consumed fruit species, seed treatments), gut and cheek pouch retention time, location of feeding sites and sleeping sites, monthly photoperiod, and movement patterns based on monthly native fruit availability using Hidden Markov models (HMM). We found that northern pigtailed macaques dispersed a majority of medium- to large-seeded species across large distances (mean > 500 m, maximum distance of 2300 m), promoting genetic mixing and colonization of plantation forests. Additionally, the macaques produced complementary seed shadows, with a sparse distribution of seeds spat out locally (mean > 50 m, maximum distance of 870 m) that probably ensures seedling recruitment of the immediate plant populations. Macaques’ large dispersal distance reliability is often underestimated and overlooked; however, their behavioral flexibility places them among the last remaining dispersers of large seeds in disturbed habitats. Our study shows that this taxon is likely to maintain significant seed dispersal services and promote forest regeneration in degraded forest fragments. [less ▲]

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See detailEcological impact of opportunist macaques (Macaca leonina) in a degraded environment of Thailand: from movement ecology to seed shadow modelisation and conservation outlook”
Gazagne, Eva ULiege

Scientific conference (2020, November 20)

https://www.youtube.com/watch?v=fx5AnGl8Xrs&feature=youtu.be

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See detailSeed Shadows of Northern Pigtailed Macaques within a Degraded Forest Fragment, Thailand
Gazagne, Eva ULiege; Pitance, Jean-Luc ULiege; Savini, Tommaso ULiege et al

in Forests (2020), 11(1184), 1-24

Abstract: Research Highlights: Frugivores able to disperse large seeds over large distances are indispensable for seedling recruitment, colonization and regeneration of tropical forests. Understanding ... [more ▼]

Abstract: Research Highlights: Frugivores able to disperse large seeds over large distances are indispensable for seedling recruitment, colonization and regeneration of tropical forests. Understanding their effectiveness as seed dispersal agents in degraded habitat is becoming a pressing issue because of escalating anthropogenic disturbance. Although of paramount importance in the matter, animal behaviour’s influence on seed shadows (i.e., seed deposition pattern of a plant population) is difficult to evaluate by direct observations. Background and Objectives: We illustrated a modeling approach of seed shadows incorporating field-collected data on a troop of northern pigtailed macaques (Macaca leonina) inhabiting a degraded forest fragment in Thailand, by implementing a mechanistic model of seed deposition with random components. Materials and Methods: We parameterized the mechanistic model of seed deposition with macaque feeding behavior (i.e., consumed fruit species, seed treatments), gut and cheek pouch retention time, location of feeding and sleeping sites, monthly photoperiod and movement patterns based on monthly native fruit availability using Hidden Markov models (HMM). Results: We found that northern pigtailed macaques dispersed at least 5.5% of the seeds into plantation forests, with a majority of medium- to large-seeded species across large distances (mean > 500 m, maximum range of 2300 m), promoting genetic mixing and colonization of plantation forests. Additionally, the macaques produced complementary seed shadows, with a sparse distribution of seeds spat out locally (mean >50 m, maximum range of 870 m) that probably ensures seedling recruitment of the immediate plant populations. Conclusions: Macaques’ large dispersal distance reliability is often underestimated and overlooked; however, their behavioral flexibility places them among the last remaining dispersers of large seeds in disturbed habitats. Our study shows that this taxon is likely to maintain significant seed dispersal services and promote forest regeneration in degraded forest fragments. [less ▲]

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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 detailBehavioral flexibility and ecological impact of opportunist northern pigtailed macaques (Macaca leonina) in a degraded environment of Thailand: Ranging pattern, foraging strategies and seed dispersal
Gazagne, Eva ULiege

Doctoral thesis (2020)

Southeast Asia experiences exceptionally high anthropogenic pressure, due to rapid human population growth. The resulting primary tropical forest loss and conversion to agricultural lands, plantations ... [more ▼]

Southeast Asia experiences exceptionally high anthropogenic pressure, due to rapid human population growth. The resulting primary tropical forest loss and conversion to agricultural lands, plantations, and infrastructures, are the driving forces leading to a massive tropical biodiversity crisis. The last remaining old-growth forests have been converted into archipelagos of forest fragments, rapidly becoming degraded. Animal and plant populations are directly threatened by degradation of forest structure, as well as distribution, quality and availability of forest resources, which ultimately modify overall ecosystem functionalities. One key feature is the extirpation of many large-bodied frugivores, the first affected by habitat degradation with a reduced fruit availability and an increased hunting pressure. Primates are particularly vulnerable to these threats, and nearly 84% of all Southeast Asian primate species are currently threatened with extinction. Only a few flexible and generalist species, such as macaques, are able to survive in human-modified landscapes. However, the way they respond to habitat degradation is not well understood yet, especially when it comes to skittish species. Since they are among the major seed-dispersal agents and play crucial roles in forest regeneration and maintenance, primates’ disappearance could result in detrimental long-term effect on tropical forest biodiversity. The omnivorous and opportunist northern pigtailed macaque (Macaca leonina) is an effective large-seed disperser, contributing to the tropical rainforest succession. However, very little is known about its ecology and behavioral response to habitat degradation. In order to understand how macaques adapt their movement ecology, ranging patterns, sleeping site selection, diet and foraging strategies under conditions of degradation, we studied the species in a degraded forest fragment within the old-growth Acacia and Eucalyptus plantations of the Sakaerat Biosphere Reserve (Sakaerat, hereafter), Northeastern Thailand. We concomitantly studied macaques’ generated seed shadow (i.e. the seed deposition pattern of a plant population) and their role as seed dispersers for potential forest regeneration. To do so, we followed a large wild-feeding troop of northern pigtailed macaques inhabiting Sakaerat for a 20-month period and collected eco-ethological data in regards to resource availability. We first habituated the troop of macaques to the observer’s presence and analyzed the habituation process over time. Based on the number of encounters, contact duration with the studied troop, and behavioral responses to the observer, we brought statistical evidences of the habituation progress over five stages: early, minimal, partial, advanced, and full. The complete habituation process took nearly thirteen months. Reduced native fruit availability in this degraded forest fragment, macaques’ limited experience of human contact, and their fission-fusion social dynamics, may explain the lengthiness of the process. Second, we investigated sleeping site selection patterns of northern pigtailed macaques over a period of 14 months by testing the hypotheses of random selection, predation avoidance, and food proximity. We identified a total of 107 sleeping sites with a low rate of reuse (N = 15 reused sleeping sites). Macaques sleeping sites were characterized by a low availability of large and tall trees and their selection pattern was not random: they slept more often in familiar areas, with a greater number of stems and a higher canopy height. These sleeping site characteristics were likely selected as an anti-predator strategy; however, food proximity also played a key role in sleeping site selection. Macaques often slept within or close to a feeding site, and selected their sleeping sites following food distribution. Third, we documented movement, ranging, and foraging patterns of northern pigtailed macaques based on 14 months of observation, and we used Hidden Markov Models (HMM) and Characteristic Hull Polygons to analyze these patterns in regard to fruit availability. Macaques’ home ranges encompassed a total of 599 ha and spanned through a natural dry-evergreen forest and a plantation forest. Our results showed that active foraging increased with higher native fruit availability, while macaques moved from foraging state to transiting to plantations and surrounding edge areas during periods of lower availability of native fruits. Accordingly, the macaques’ diet shifted from fleshy to dry fruits, such as the introduced Acacia species. Our results showed that the diet and movement ecology adaptations of northern pigtailed macaques in this degraded forest fragment were primarily dependent on availability of native fruit species, and that foraging strategies in the Sakaerat troop differed from northern pigtailed macaque populations inhabiting the nearby primary forest of Khao Yai National Park. Fourth, we illustrated a modeling approach of seed shadows, which incorporated field-collected data on the Sakaerat troop. We adapted a deterministic model of seed deposition with random components. We parameterized the model with macaque feeding behavior (i.e. consumed fruit species, seed treatments), gut and cheek pouch retention time, feeding and sleeping site location, daily activity, and movement patterns based on monthly fruit availability (analyzed with HMM). We found that northern pigtailed macaques dispersed many medium- to large-seeded species, across long distances in the degraded native forest and toward plantation forests (mean of dispersal distance > 500 m with a maximum range of 2300 m), and produced complementary seed shadows, with a sparse distribution of seeds spat out locally (mean > 50 m with a maximum range of 870 m). Our results showed that northern pigtailed macaques are effective seed dispersers in this degraded habitat. Overall, our findings provide novel insights regarding northern pigtailed macaques’ adaptability to habitat degradation, which include selection of numerous sleeping sites following food availability, use of exotic Acacia species in plantations to cope with native fruit scarcity, and use of large home range. These behavioral profiles result in long-distance dispersal events, giving an overview of their contributions to forest restoration and maintenance of ecosystem functions within their ranges. Our results bring a significant contribution to the current knowledge of the ecology and factors affecting ranging patterns, resource use, and seed dispersal effectiveness of the northern pigtailed macaque classified as vulnerable but still poorly-known, and constitute an essential starting point toward designing appropriate conservation strategies. [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 detailReliability of macaques as seed dispersers
Sengupta, Asmita; Gazagne, Eva ULiege; Albert-Daviaud, Aurélie et al

in American Journal of Primatology (2020)

Seed dispersal is an ecological process crucial for forest regeneration and recruitment. To date, most studies on frugivore seed dispersal have used the seed dispersal effectiveness framework and have ... [more ▼]

Seed dispersal is an ecological process crucial for forest regeneration and recruitment. To date, most studies on frugivore seed dispersal have used the seed dispersal effectiveness framework and have documented seed‐handling mechanisms, dispersal distances and the effect of seed handling on germination. In contrast, there has been no exploration of “disperser reliability” which is essential to determine if a frugivore is an effective disperser only in particular regions/years/seasons or across a range of spatio‐temporal scales. In this paper, we propose a practical framework to assess the spatial reliability of frugivores as seed dispersers. We suggest that a frugivore genus would be a reliable disperser of certain plant families/genera if: (a) fruits of these plant families/genera are represented in the diets of most of the species of that frugivore, (b) these are consumed by the frugivore genus across different kinds of habitats, and (c) these fruits feature among the yearly staples and preferred fruits in the diets of the frugivore genus. Using this framework, we reviewed frugivory by the genus Macaca across Asia to assess its spatial reliability as seed dispersers. We found that the macaques dispersed the seeds of 11 plant families and five plant genera including at least 82 species across habitats. Differences in fruit consumption/preference between different groups of macaques were driven by variation in plant community composition across habitats. We posit that it is essential to maintain viable populations of macaques across their range and keep human interventions at a minimum to ensure that they continue to reliably disperse the seeds of a broad range of plant species in the Anthropocene. We further suggest that this framework be used for assessing the spatial reliability of other taxonomic groups as seed dispersers. [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

in Revue de Primatologie (2019, October 04)

Space-use patterns and foraging strategies are crucial to understand the ecological resilience of primates in degraded habitats. However, detailed ranging data are scarce, especially for Southeast Asian ... [more ▼]

Space-use patterns and foraging strategies are crucial to understand the ecological resilience of primates in degraded habitats. However, detailed ranging data are scarce, especially for Southeast Asian primate species. Our study examined movement, ranging, and foraging patterns within a group of 141 ± 10 northern pigtailed macaques (Macaca leonina). We followed the macaques and recorded their diet and movements, in regard to fruit availability, within a degraded habitat with reclaimed plantation forest in the Sakaerat Biosphere Reserve, northerneastern Thailand. Using hidden Markov Models (HMMs) and Characteristic Hull Polygons (CHPs), we analyzed these patterns for 14 months in regard of fruit availability. We found that the macaques’ home range of 599 ha covered two types of forest with asynchronous fruit availability, the dry-evergreen forest (DEF) and the plantation forest. During high fruit availability in DEF, macaques were more likely to forage actively in the interior native DEF. By contrast, during low fruit availability in DEF, macaques foraged less in a continuous way and repeatedly moved from a foraging behavior to a transiting one. They also extended their range to plantation forest and edge areas, which resulted in significantly larger monthly home range, core area, longer daily path length, lower site fidelity, as well as faster and more oriented movement. The concomitant macaques’ diet shifted from fleshy to dry fruits such as exotic Acacia species. Our results show that northern pigtailed macaques adapt their movement dynamic, ranging pattern and diet according to fruit availability. They respond primarily to the availability of native fruits, then travel directly toward plantation forest or edge areas with predictable food resources when fruit are scarce. These patterns reflect both energy-maximizing and energy-minimizing strategies and suggest a way used by macaques to cope with habitat degradation. Our study combining ranging pattern analyses with HMMs provides a new and complete picture of movement, ranging and foraging patterns in macaques living in a degraded forest fragment. It contributes to deepen knowledge about the ecology and factors affecting the ranging patterns and resource use of this poorly-known and vulnerable species, a preliminary step to design appropriate conservation strategies. [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 detailCultural flies: Conformist social learning in fruitflies predicts long-lasting mate-choice traditions
Danchin, E.; Nöbel, S.; Pocheville, A. et al

in Science (2018), 362(6418), 1025-1030

Despite theoretical justification for the evolution of animal culture, empirical evidence for it beyond mammals and birds remains scant, and we still know little about the process of cultural inheritance ... [more ▼]

Despite theoretical justification for the evolution of animal culture, empirical evidence for it beyond mammals and birds remains scant, and we still know little about the process of cultural inheritance. In this study, we propose a mechanism-driven definition of animal culture and test it in the fruitfly. We found that fruitflies have five cognitive capacities that enable them to transmit mating preferences culturally across generations, potentially fostering persistent traditions (the main marker of culture) in mating preference. A transmission chain experiment validates a model of the emergence of local traditions, indicating that such social transmission may lead initially neutral traits to become adaptive, hence strongly selecting for copying and conformity. Although this situation was suggested decades ago, it previously had little empirical support. © 2018 American Association for the Advancement of Science. All rights reserved. [less ▲]

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See detailEcological impact of the opportunist northern pigtailed macaques (Macaca leonina) in degraded environments: Ranging pattern, seed dispersal and predatory behavior in Central Thailand
Gazagne, Eva ULiege

Conference (2015, December 01)

Deforestation and fragmentation have become the most important threats for biodiversity due to both plant and animal dispersal movement limitation impacting seed dispersal and prey-predator interactions ... [more ▼]

Deforestation and fragmentation have become the most important threats for biodiversity due to both plant and animal dispersal movement limitation impacting seed dispersal and prey-predator interactions. Through the study of the adaptive and opportunistic northern pigtailed macaque (Macaca leonina), this PhD aims to assess how fragmentation affects the macaques’ habitat use, seed dispersal and predatory behavior in a highly fragmented and degraded environment (Sakaerat Biosphere Reserve, Central Thailand). Investigating the ranging pattern and feeding behavior of this macaque, acknowledged as an effective seed disperser, in a disturbed environment, will provide a concrete example of potential forest regeneration by a natural agent. Moreover, as this is a very efficient passerine nest predator, the study of its ranging behavior will allow assessing the extent of a generalist predator efficiency in a fragmented environment. [less ▲]

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