Specialization on Guadua Bamboo Seeds by Three Bird Species in the Atlantic Forest of Argentina

Most bamboos are semelparous. Their synchronous masting events occur on a cycle of 3–120 yr and represent an extremely pulsed resource for granivorous birds. Although many bird species feed occasionally on bamboo seeds, there are constraints to specializing on such a fluctuating resource and few bird species are known to specialize on bamboo seeds. Three of these bird species are endemic to the Atlantic forest of South America: the purple-winged ground-dove Claravis godefrida , buff-fronted seedeater Sporophila frontalis , and Temminck's seedeater Sporophila falcirostris . All three species are irregularly recorded in the province of Misiones, Argentina. We compared the temporal and spatial patterns of records of these birds in Misiones to masting events of the five common bamboos: yatevó Guadua trinii , takuaruzú Guadua chacoensis , takuapí Merostachys claussenii , pitinga Chusquea tenella , and takuarembó Chusquea ramosissima . All bird records coincided with times and places where Guadua bamboos ( G. trinii and G. chacoensis ) were known or estimated to have seeds. None of the bird species occurred during masting events of Merostachys or Chusquea , unless Guadua was also masting. We discuss relevant ecological and morphological features of the birds that might bear on their association with Guadua bamboos and that might be key to their conservation.     

High flexibility in diet and ranging patterns in two golden monkey (Cercopithecus mitis kandti) populations in Rwanda

Many primates exhibit behavioral flexibility which allows them to adapt to environmental change and different habitat types. The golden monkey (Cercopithecus mitis kandti) is a little-studied endangered primate subspecies endemic to the Virunga massif and the Gishwati forest in central Africa. In the Virunga massif, golden monkeys are mainly found in the bamboo forest, while in the Gishwati forest they live in mixed tropical montane forest. Here we describe and compare the diet of golden monkeys in both fragments. Over 24 consecutive months from January 2017 we used scan sampling to record feeding and ranging behavior of two Virunga groups and one Gishwati group totaling ca. 240 individuals. We also examined the phenology of bamboo and fruit trees, key seasonal food plant species for the monkeys. Golden monkeys fed on more than 100 plant species. The Virunga groups were mostly folivorous (between 72.8% and 87.16% of the diet) and fed mostly on young bamboo leaves and bamboo shoots, while 48.69% of the diet of the Gishwati group consisted of fruit from 22 different tree and shrub species. Bamboo shoots and fruit are seasonally available foods and were consumed regularly throughout the period when they were available. Despite being the smallest of the three study groups, the Gishwati group had a larger home range area (150.07 ha) compared to both Virunga groups (25.24 and 91.3 ha), likely driven by the differences in availability and distribution of fruit and bamboo in the habitats. Like other blue monkey subspecies, golden monkeys appear to have a flexible dietary strategy enabling them to adjust diet and ranging behavior to local habitats and available food resources. Additional studies and continuing conservation efforts are needed to better understand how variation in feeding and ranging ecology affects reproduction, population growth, and carrying capacity.     

Diet composition of chimpanzees inhabiting the montane forest of Kahuzi,Democratic Republic of Congo

The diet of chimpanzees was investigated by direct observations, feeding remains, and fecal analysis from January 1994 to December 2000 in the montane forest of Kahuzi-Biega National Park. A total of 171 food items were identified, among which 156 items were plant materials belonging to 114 species from 57 taxonomic families. Chimpanzees consumed 66 species of fruits (62 species of pulps and four species of seeds). Results of fecal analysis showed that fig fruits were the most frequently eaten. Their seeds occurred in 92% of a total of 7212 chimpanzee fecal samples. The chimpanzees changed their diet according to seasonal and annual variations in both abundance and diversity of fruit species. However, they are very selective frugivores. Only a few pulp-fruit species are regularly identified in their fecal samples. During the rainy season, when ripe fruit was scarce, chimpanzees relied heavily on piths and leaves. They swallowed leaves of two species of Commelinaceae without chewing, probably for medical purposes. Animal foods were eaten infrequently. The montane forest of Kahuzi, where chimpanzees range up to 2600 m above sea level, may be the highest altitudinal limit ever recorded for their distribution. Compared to other chimpanzee habitats, Kahuzi has a low diversity of fruit species and the availability of a few pulp-fruit species may be critical to the survival of Kahuzi chimpanzees.     

Frugivore Behavioural Details Matter for Seed Dispersal: A Multi-Species Model for Cantabrian Thrushes and Trees

Animal movement and behaviour is fundamental for ecosystem functioning. The process of seed dispersal by frugivorous animals is a showcase for this paradigm since their behaviour shapes the spatial patterns of the earliest stage of plant regeneration. However, we still lack a general understanding of how intrinsic (frugivore and plant species traits) and extrinsic (landscape features) factors interact to determine how seeds of a given species are more likely to be deposited in some places more than in others. We develop a multi-species mechanistic model of seed dispersal based on frugivore behavioural responses to landscape heterogeneity. The model was fitted to data from three-years of spatially-explicit field observations on the behaviour of six frugivorous thrushes and the fruiting patterns of three fleshy-fruited trees in a secondary forest of the Cantabrian range (N Spain). With such model we explore how seed rain patterns arise from the interaction between animal behaviour and landscape heterogeneity. We show that different species of thrushes respond differently to landscape heterogeneity even though they belong to the same genus, and that provide complementary seed dispersal functions. Simulated seed rain patterns are only realistic when at least some landscape heterogeneity (forest cover and fruit abundance) is taken into account. The common and simple approach of re-sampling movement data to quantify seed dispersal produces biases in both the distance and the habitat at which seeds arrive. Movement behaviour not only affects dispersal distance and seed rain patterns but also can affect frugivore diet composition even if there is no built-in preference for fruiting species. In summary, the fate of seeds produced by a given plant species is strongly affected by both the composition of the frugivore assemblage and the landscape-scale context of the plant location, including the presence of fruits from other plants (from the same or different species).     

Frugivory and Seed Dispersal by Northern Pigtailed Macaques (Macaca leonina), in Thailand

Tropical rain forest conservation requires a good understanding of plant–animal interactions. Seed dispersal provides a means for plant seeds to escape competition and density-dependent seed predators and pathogens and to colonize new habitats. This makes the role and effectiveness of frugivorous species in the seed dispersal process an important topic. Northern pigtailed macaques (Macaca leonina) may be effective seed dispersers because they have a diverse diet and process seeds in several ways (swallowing, spitting out, or dropping them). To investigate the seed dispersal effectiveness of a habituated group of pigtailed macaques in Khao Yai National Park, Thailand, we examined seed dispersal quantity (number of fruit species eaten, proportion in the diet, number of feces containing seeds, and number of seeds processed) and quality (processing methods used, seed viability and germination success, habitat type and distance from parent tree for the deposited seeds, and dispersal patterns) via focal and scan sampling, seed collection, and germination tests. We found thousands of seeds per feces, including seeds up to 58 mm in length and from 88 fruit species. Importantly, the macaques dispersed seeds from primary to secondary forests, via swallowing, spitting, and dropping. Of 21 species, the effect of swallowing and spitting was positive for two species (i.e., processed seeds had a higher % germination and % viability than control seeds), neutral for 13 species (no difference in % germination or viability), and negative (processed seeds had lower % germination and viability) for five species. For the final species, the effect was neutral for spat-out seeds but negative for swallowed seeds. We conclude that macaques are effective seed dispersers in both quantitative and qualitative terms and that they are of potential importance for tropical rain forest regeneration.     

Diet of Grauer's Gorillas in the Montane Forest of Kahuzi,Democratic Republic of Congo

We describe the diet of a semihabituated group of Grauer's gorillas (Gorilla beringei graueri) inhabiting the montane forest of Kahuzi-Biega National Park, Democratic Republic of Congo, based on direct observations, feeding remains in their fresh trails, and fecal samples collected over 9 yr. We examined fruit availability in their habitat; consumption of fruit, vegetative, and animal food; and daily intake of vegetative plant food using a transect, fruit monitoring trails, fecal analysis, and tracing of the animal's daily trails between consecutive nest sites. The fruit food repertoire of Kahuzi gorillas resembles that of western and eastern lowland gorillas inhabiting lowland tropical forests, while their vegetative food repertoire resembles that of mountain gorillas inhabiting montane forests. Among 236 plant foods (116 species), leaves, pith, and barks constitute the major parts (70.2%), with fruit making up the minor part (19.7%). About half (53.2%) of the total fecal samples included fruit remains. The gorillas used leaves, stems and other vegetative plant parts as staples. Their fruit intake was similar to that reported for mountain gorillas in Bwindi. They ate animal foods, including earthworms, on rare occasions. Variation in fruit consumption was positively associated with variation in fruit production. The gorillas ate fig fruits frequently; fig intake is positively correlated with that of other fruits, and figs were not fallback foods. They relied heavily on bamboo shoots on a seasonal basis; however, no bamboo shoots were available for several years after a major flowering event. Our results support the argument that variation in gorilla diets mostly reflects variation in vegetational composition of their habitats.     

Influence of between-year variation in the density of Rhus <Emphasis Type="Italic">trichocarpa</Emphasis> fruits on the removal of fruit by birds

The fruiting phenology and fruit removal patterns of Rhus trichocarpa Miq. (Anacardiaceae) were investigated in a warm-temperate secondary forest in Japan. Mature fruits of this species are dispersed by birds. Effects of fruit display size and canopy openness on fruit removal were investigated in years with different fruit densities (i.e., masting and non-masting years). Moreover, effects of increased canopy openness during winter on fruit removal were also investigated. Seasonal patterns of fruit removal were quite different between masting and non- masting years. In the non-mast year, fruits were removed by birds soon after maturation in the summer. In contrast, in the mast year, fruits were removed gradually by birds from summer to winter. Moreover, the rate of fruit removal was greater for trees with a larger display size in the non-mast year, whereas that was greater for trees with greater canopy openness in the mast year. Canopy openness increased in winter, and fruit removal in winter was enhanced in trees with a more open canopy only in the non-mast year. These observations strongly suggest that avian dispersers became satiated in the mast year, whereas fruit removal was enhanced in the non-mast year. In the mast year, although many fruits were not dispersed until winter, they were neither depredated nor rotten, and the long period of fruit removal by birds may have enhanced fruit dispersal. The large abundance of seedlings and saplings of this species in Japanese secondary forests suggests that this fruiting strategy is beneficial.     

Density-dependent reproductive success among sympatric dipterocarps during a major mast fruiting event

Although masting in Southeast Asia is characterized by the interspecific synchronization of reproduction, little is known about the variation in regeneration strategies among sympatric tree species during major masting events. Herein, we examined the hypothesis that non-abundant species achieve greater seed survival per seed production at the pre- and post-dispersal stages by synchronizing reproduction with abundant species. During the masting event from May to September 2010, we installed seed traps in a primary forest plot of the Deramakot Forest Reserve, Borneo. To identify the possible causes of post-dispersal seed mortality, we conducted a seed-sowing experiment from September 2010 to July 2011 in a primary forest plot with high community-level dipterocarp seed density and two surrounding secondary forests with low seed densities. An abundant species (Shorea multiflora) produced more seeds than other species and exhibited a lower survival rate during the pre-dispersal stage. The ratio of aborted seeds was greater in species with greater seed production, while the ratio of seeds predated by insects was not, suggesting that resource limitations and/or greater inbreeding frequency may explain inefficient seed production. Interspecific variation was rarely observed for post-dispersal seed survival rates. Our study highlights the density-dependent variation in reproductive success between abundant and non-abundant dipterocarp species at the pre-dispersal stage. Non-abundant species achieved greater reproductive success by synchronizing reproduction with the masting of abundant species, which might be an important mechanism for sustainability of rare species populations.     

Diet and Feeding Behavior of <Emphasis Type="Italic">Leontopithecus chrysomelas</Emphasis> (Callitrichidae) in Degraded Areas of the Atlantic Forest of South-Bahia,Brazil

Habitat disturbance alters plant diversity and food resource availability, affecting the ecology, and ultimately the survival and reproduction, of species depending on those plants. Studies in degraded areas serve to improve our understanding of the consequences of habitat modification for endangered species and to guide conservation actions. We studied diet composition, monthly variation in feeding behavior and fruit feeding time, and dietary diversity in two golden-headed lion tamarin (Leontopithecus chrysomelas) groups ranging in a degraded area of the Atlantic Forest in South-Bahia, Brazil, over a 12-mo period. We recorded feeding behavior and food items consumed through continuous observations and focal animal sampling, and performed dietary analyses on samples from consumed fruits. Substrate manipulation to search for animal prey was the feeding activity most frequently observed, followed by fruit consumption. We observed nectar drinking and exudate feeding at low frequencies from April through July. Bromeliads were the principal foraging substrate. We observed the use of 114 plant species, confirming the large dietary diversity reported for the species. Individual trees from the family Melastomataceae, common in degraded forests, accounted for the highest visiting frequencies (40%). Fruit availability was the main factor explaining variation in monthly fruit feeding time, despite the absence of climatic seasonality. Nutritional or energetic characteristics did not affect fruit choice. Differences in floristic composition appear to be a major determinant of the species’ diet in different study areas. Regional forest restoration programs should consider including advanced forest species, to improve both forest quality and animal mobility between fragments.     

Influence of Fruit Availability on Fruit Consumption in a Generalist Primate,the Rhesus Macaque <Emphasis Type="Italic">Macaca mulatta</Emphasis>

Fluctuations in resource availability occur in all ecosystems. To survive, species must alter their foraging strategies according to the quantity, quality, and distribution of available food. The rhesus macaque (Macaca mulatta), a commensal primate, is considered a generalist omnivore and very few studies have addressed how its feeding strategies change with respect to resource availability. We examined dietary diversity and frugivory levels in a group of rhesus macaques at the Buxa Tiger Reserve in northern India across one year. Using behavioural observations of diet and phenological monitoring, we found that although rhesus macaques fed on 107 food items including leaves, flowers, fruits, seeds, and insects, fruits made up ca. 74% of their diet. Fruit consumption correlated positively with fruit availability, but fruit preference appeared to play an important role; 16% of all the fruit species they fed on accounted for >50% of all fruit feeding observations. We suggest that afforestation programs involving preferred fruit species at the agricultural land–forest interface would prevent forest groups of rhesus macaques from gravitating toward human habitations and reduce conflict over anthropogenic resources. We further propose that the movement of certain primates in the direction of human habitations may be contingent on resource availability and food preference rather than an inherent propensity to gravitate to anthropogenic areas.     

Revealing secondary seed removers: results from camera trapping

This paper reports the results of the first study on secondary seed removal of seeds dispersed by Sykes’ monkeys (Cercopithecus albogularis) using camera traps in Africa. Patterns of primary seed dispersal are often superimposed by secondary conveyance, emphasising the need to study these secondary processes carefully. As the agents and mechanisms of seed dispersal are often concealed, being carried out by cryptic or nocturnal animals in dense vegetation, camera trapping was deemed a viable means to investigate secondary removal of seeds disseminated by C. albogularis in the Western Soutpansberg, South Africa. Camera traps were established at preferred feeding trees of the focal Sykes’ monkey group to identify animal species that remove seeds and fruits spat and dropped to the forest floor and seed removal observations were carried out. This method proved to be effective in identifying seed removers and also allowed to get indications about the quantities of seeds removed. Ten animal species were recorded visiting the trees, of which eight were observed removing seeds and fruits. Overall seed and fruit removal rates were high, indicating that the foraging behaviour of C. albogularis attracts many terrestrial frugivores.     

13种竹类植物的果实形态特征

对9属13种竹类植物的果实形态特征进行了观察和描述,并对果实形态指标(包括带稃长、带稃宽、带稃长宽比、去稃长、去稃宽、去稃长宽比以及千粒质量)进行了方差分析和变异系数( CV)分析。结果表明：13种竹类植物果实均为基本型颖果,外带内、外稃,果皮质薄不开裂;外稃顶端多数不具芒;果实多具明显的腹部纵沟槽;稃片颜色多呈灰褐色、黄褐色、棕色、灰色或灰绿色;成熟果实颜色多为棕色、棕黑色、棕红色、黄棕色、灰色、灰褐色、黄褐色、黑褐色或褐色;果实形状基本为椭圆形类、卵圆形类和长圆柱形类。供试13种竹类植物间的果实带稃长、带稃宽、带稃长宽比、去稃长、去稃宽、去稃长宽比以及千粒质量均有极显著差异,并且这7个指标的种间CV值分别为34.60%、28.19%、54.63%、21.22%、27.96%、38.19%和57.38%,但各指标的种内CV值明显小于其种间CV值。综合分析结果显示：果实竹类植物果实外稃顶端是否具芒、稃片颜色、稃片对果实的包裹程度、稃片长度与果实长度的关系、去稃果实形状、成熟果实颜色、腹部纵沟槽是否明显和花柱是否宿存等特征可作为竹类植物属和种分类的参考依据;其中,果实千粒质量、带稃长宽比和去稃长宽比较果实长和宽更适合作为竹类植物种的分类依据。此外,13种竹类植物中,刚竹属( Phyllostachys Sieb. et Zucc.)刚竹组( Sect. Phyllostachys)的毛竹﹝Phyllostachys edulis ( Carr.) J. Houz.﹞、淡竹( P. glauca McClure)和乌哺鸡竹( P. vivax McClure)的果实形态极其相似,均具有较长的宿存花柱,明显异于其他竹类植物的果实,可将此特征作为刚竹属种类的识别特征之一。     

Dense understory dwarf bamboo alters the retention of canopy tree seeds

Tree seed retention is thought to be an important factor in the process of forest community regeneration. Although dense understory dwarf bamboo has been considered to have serious negative effects on the regeneration of forest community species, little attention has been paid to the relationship between dwarf bamboo and seed retention. In a field experiment we manipulated the density of Fargesia decurvata, a common understory dwarf bamboo, to investigate the retention of seeds from five canopy tree species in an evergreen and deciduous broad-leaved mixed forest in Jinfoshan National Nature Reserve, SW China. We found that the median survival time and retention ratio of seeds increased with the increase in bamboo density. Fauna discriminately altered seed retention in bamboo groves of different densities. Arthropods reduced seed survival the most, and seeds removed decreased with increasing bamboo density. Birds removed or ate more seeds in groves of medium bamboo density and consumed fewer seeds in dense or sparse bamboo habitats. Rodents removed a greater number of large and highly profitable seeds in dense bamboo groves but more small and thin-husked seeds in sparse bamboo groves. Seed characteristics, including seed size, seed mass and seed profitability, were important factors affecting seed retention. The results suggested that dense understory dwarf bamboo not only increased seeds concealment and reduced the probability and speed of seed removal but also influenced the trade-off between predation and risk of animal predatory strategies, thereby impacting the quantity and composition of surviving seeds. Our results also indicated that dense understory dwarf bamboo and various seed characteristics can provide good opportunities for seed storage and seed germination and has a potential positive effect on canopy tree regeneration.     

Old World fruit bats can be long-distance seed dispersers through extended retention of viable seeds in the gut

Seed dispersal and pollination by animals play a crucial role in the maintenance of forest ecosystems worldwide. Frugivorous bats are important pollen and seed dispersers in both the Palaeo- and Neotropics, and at least 300 plant species are known to rely on Old World fruit bats (Megachiroptera, Pteropodidae) for their propagation. However, rapid food transit times (generally less than 30 minutes) in frugivorous bats have been thought to limit their ability to disperse seeds to just a few tens of kilometres. Here we demonstrate regular daytime (greater than 12 hours) retention of food and viable fig seeds (Ficus, Moraceae) in the gut of the Old World fruit bat Cynopterus sphinx: a behaviour not previously reported for any frugivorous bat. Field observations indicate that this behaviour also occurs in other genera. Old World fruit bats are highly mobile and many species undertake considerable foraging and migration flights. Our findings indicate that Old World fruit bats have the potential to disperse small seeds hundreds of kilometres. This necessitates a reappraisal of their importance in transporting zoochorous seeds to remote areas and facilitating gene flow between isolated populations of plants, both within mainlands and across ocean barriers.     

Diet and feeding behaviour of Indri indri in a low-altitude rain forest

The diet and feeding behaviour of Indri indri were investigated in the Betampona Reserve, eastern Madagascar, over 12 months from February 2000 to February 2001. The highly folivorous diet of this species was confirmed--feeding on foliage (leaves and petioles) accounting for 82% of feeding records. Immature leaves were the preferred dietary item, but at times of relative scarcity mature leaves, fruit, seeds, flowers and bark were substituted. The indri were observed to feed on parts from 22 plant families, 37 genera and at least 42 species. The most important plant families in the diet of Indri were Lauraceae, Clusiaceae and Myristicaceae. Most feeding at Betampona was observed at 5-20 m above the forest floor amongst small (2.1-5.0 cm), oblique/horizontal supports (0-45 degrees). The indri spent 41.4% of their active period feeding most commonly in above-branch postures. Studies such as this are important for the development of conservation management plans for this endangered species.     

Potential Role of Masting by Introduced Bamboos in Deer Mice (Peromyscus maniculatus) Population Irruptions Holds Public Health Consequences

We hypothesized that the ongoing naturalization of frost/shade tolerant Asian bamboos in North America could cause environmental consequences involving introduced bamboos, native rodents and ultimately humans. More specifically, we asked whether the eventual masting by an abundant leptomorphic (“running”) bamboo within Pacific Northwest coniferous forests could produce a temporary surfeit of food capable of driving a population irruption of a common native seed predator, the deer mouse (Peromyscus maniculatus), a hantavirus carrier. Single-choice and cafeteria-style feeding trials were conducted for deer mice with seeds of two bamboo species (Bambusa distegia and Yushania brevipaniculata), wheat, Pinus ponderosa, and native mixed diets compared to rodent laboratory feed. Adult deer mice consumed bamboo seeds as readily as they consumed native seeds. In the cafeteria-style feeding trials, Y. brevipaniculata seeds were consumed at the same rate as native seeds but more frequently than wheat seeds or rodent laboratory feed. Females produced a median litter of 4 pups on a bamboo diet. Given the ability of deer mice to reproduce frequently whenever food is abundant, we employed our feeding trial results in a modified Rosenzweig-MacArthur consumer-resource model to project the population-level response of deer mice to a suddenly available/rapidly depleted supply of bamboo seeds. The simulations predict rodent population irruptions and declines similar to reported cycles involving Asian and South American rodents but unprecedented in deer mice. Following depletion of a mast seed supply, the incidence of Sin Nombre Virus (SNV) transmission to humans could subsequently rise with dispersal of the peridomestic deer mice into nearby human settlements seeking food.     

Fruit Traits in Baboon Diet: A Comparison with Plant Species Characteristics in West Africa

Primate fruit choice among plant species has been attributed to different morphological plant and fruit characteristics. Despite a high abundance of animal-dispersed plant species in the savanna–forest mosaic of West Africa, few data are available on the interplay between morphological fruit traits and primate fruit consumers in this ecosystem. We tested whether olive baboons (Papio anubis) at Comoé National Park, north-eastern Ivory Coast, prefer fruit species with particular characteristics relative to the availability of these traits among the woody plant species at the study site. Specifically we were interested in the suites of traits that best predict fruit choice and seed handling by baboons. The baboons ate fruit/seeds from 74 identified plant species, representing 25 percent of the regional pool of woody plant species. They preferred trees to shrubs and lianas as fruit sources. Otherwise, baboons seemed to consume whatever fruit type, color, and size of fruit and seeds available, though they especially included larger fruit into their diet. Against expectations from the African bird–monkey fruit syndrome of brightly colored drupes and berries, baboons ate mostly species having large, dull-colored fruit. Fruit type and color best described whether baboons included a species into their diet, whereas fruit type and seed size best predicted whether baboons predated upon the seeds of their food plant species. As most plant species at the study site had medium-sized to large fruits and seeds, large frugivores like baboons might be particularly important for plant fitness and plant community dynamics in West African savanna–forest ecosystems.     

Functional heterogeneity in a plant–frugivore assemblage enhances seed dispersal resilience to habitat loss

The ability of ecosystems to maintain their functions after disturbance (ecological resilience) depends on heterogeneity in the functional capabilities among species within assemblages. Functional heterogeneity may affect resilience by determining multiplicity between species in the provision of functions (redundancy) and complementarity between species in their ability to respond to disturbances (response diversity), but also by promoting the maintenance of biological information that enables ecosystems to reorganize themselves (ecological memory). Here, we assess the role of the components of the functional heterogeneity of a plant–frugivore assemblage on the resilience of seed dispersal to habitat loss. For three years, we quantified the distributions of fruits, frugivorous thrushes (Turdus spp.) and dispersed seeds, as well as frugivore diet and movement, along a gradient of forest cover in N Spain. The abundances and the spatial distributions of fruits and birds varied between years. The different thrushes showed similar diets but differed in spatial behavior and response to habitat loss, suggesting the occurrence of both functional redundancy and response diversity. Forest cover and fruit availability affected the spatial distribution of the whole frugivore assemblage. Fruit tracking was stronger in years when fruits were scarcer but more widespread across the whole fragmented landscape, entailing larger proportions of seeds dispersed to areas of low forest cover and open microhabitats. Rather than depending on redundancy and/or response diversity, seed dispersal resilience mostly emerged from the ecological memory conferred by the inter‐annual variability in fruit production and the ability of thrushes to track fruit resources across the fragmented landscape. Ecological memory also derived from the interaction of plants and frugivores as source organisms (trees in undisturbed forest), mobile links (birds able to disperse seeds into the disturbed habitat), and biological legacies (remnant trees and small forest patches offering scattered fruit resources across the landscape).     

Diet of a Japanese Macaque Troop in the Coniferous Forest of Yakushima

I studied the diet of a troop of Japanese macaques in the coniferous forest of Yakushima over one year via focal animal sampling. Fiber-rich foods constituted 45% of annual feeding time, and mature leaves constituted 38% of total feeding time. Feeding time on fruits and seeds was only 13% and 4%, respectively. Flowers and fungi contributed a considerable amount of annual feeding time: 15% and 14%, respectively. Their diet changed seasonally. They fed on more fruits and seeds in response to increased availability, and when these foods were not available, they ate mature leaves. When the temperature was low, they ate more herbs, possibly to save energy by not climbing trees and staying in sunny places. The results imply two dietary characteristics of the species that might relate to adaptations in temperate regions, where fruit is available during a limited season and fiber-rich foods are the only candidate of fallback food. They are capable of digesting a large amount of fiber-rich food, but at the same time they preferentially select high-quality fruits or seeds when they are available.     

Diet and seasonal changes in sympatric gorillas and chimpanzees at Kahuzi–Biega National Park

Based on 8 years of observations of a group of western lowland gorillas (Gorilla beringei graueri) and a unit-group of chimpanzees (Pan troglodytes schweinfurthii) living sympatrically in the montane forest at Kahuzi–Biega National Park, we compared their diet and analyzed dietary overlap between them in relation to fruit phenology. Data on fruit consumption were collected mainly from fecal samples, and phenology of preferred ape fruits was estimated by monitoring. Totals of 231 plant foods (116 species) and 137 plant foods (104 species) were recorded for gorillas and chimpanzees, respectively. Among these, 38% of gorilla foods and 64% of chimpanzee foods were eaten by both apes. Fruits accounted for the largest overlap between them (77% for gorillas and 59% for chimpanzees). Gorillas consumed more species of vegetative foods (especially bark) exclusively whereas chimpanzees consumed more species of fruits and animal foods exclusively. Although the number of fruit species available in the montane forest of Kahuzi is much lower than that in lowland forest, the number of fruit species per chimpanzee fecal sample (average 2.7 species) was similar to that for chimpanzees in the lowland habitats. By contrast, the number of fruit species per gorilla fecal sample (average 0.8 species) was much lower than that for gorillas in the lowland habitats. Fruit consumption by both apes tended to increase during the dry season when ripe fruits were more abundant in their habitat. However, the number of fruit species consumed by chimpanzees did not change according to ripe fruit abundance. The species differences in fruit consumption may be attributed to the wide ranging of gorillas and repeated usage of a small range by chimpanzees and/or to avoidance of inter-specific contact by chimpanzees. The different staple foods (leaves and bark for gorillas and fig fruits for chimpanzees) characterize the dietary divergence between them in the montane forest of Kahuzi, where fruit is usually scarce. Gorillas rarely fed on insects, but chimpanzees occasionally fed on bees with honey, which possibly compensate for fruit scarcity. A comparison of dietary overlap between gorillas and chimpanzees across habitats suggests that sympatry may not influence dietary overlap in fruit consumed but may stimulate behavioral divergence to reduce feeding competition between them.