Food Trees Research Articles

Does phenology distinguish bitter and sweet African bush mango trees (Irvingia spp., Irvingiaceae)?

This phenological analysis of bitter and sweet bush mango trees is part of their biosystematics. It supports the species distinction hypothesis postulated by Harris (Bull J Bot Nat Belg 65(1–2):143–196, 1996 ) and Lowe et al. (Mol Ecol 9:831–841, 2000 ). African Bush Mango trees are priority food trees in Sub-Saharan Africa. The unclear distinction between bitter and sweet fruited trees is still subject to taxonomic debate. This hinders their effective use and conservation programmes. This study investigates differences in phenological behaviour between bitter and sweet fruited populations and their taxonomic implications. Monthly phenological description data on seven populations of bitter or sweet bush mangos across Benin and Togo were used to assess within and between mango type phenological diversity, to discriminate bitter and sweet trees and to evaluate their responses to environmental factors. The phenological states differentiating bitter and sweet trees were identified and individual trees were classified based on the discriminating phenological characters. Finally, phenological variation was analyzed with time of the year, soil type, type of bush mango tree, and climatic zone. Phenological diversity varies significantly among populations. Bitter and sweet trees have consistently different phenological states. Bitter trees have a lower phenological diversity for all phenological phases throughout the year compared to sweet trees, possibly due to their limited distribution range in the study area. The tree types also differ in their reproductive responses to environmental factors, but did not respond differently to soils. These results support the hypothesis that bitter and sweet trees represent different taxa and we suggest for efficient conservation purpose to consider them as different species.

Where to nest? Ecological determinants of chimpanzee nest abundance and distribution at the habitat and tree species scale.

Conversion of forests to anthropogenic land-uses increasingly subjects chimpanzee populations to habitat changes and concomitant alterations in the plant resources available to them for nesting and feeding. Based on nest count surveys conducted during the dry season, we investigated nest tree species selection and the effect of vegetation attributes on nest abundance of the western chimpanzee, Pan troglodytes verus, at Lagoas de Cufada Natural Park (LCNP), Guinea-Bissau, a forest-savannah mosaic widely disturbed by humans. Further, we assessed patterns of nest height distribution to determine support for the anti-predator hypothesis. A zero-altered generalized linear mixed model showed that nest abundance was negatively related to floristic diversity (exponential form of the Shannon index) and positively with the availability of smaller-sized trees, reflecting characteristics of dense-canopy forest. A positive correlation between nest abundance and floristic richness (number of plant species) and composition indicated that species-rich open habitats are also important in nest site selection. Restricting this analysis to feeding trees, nest abundance was again positively associated with the availability of smaller-sized trees, further supporting the preference for nesting in food tree species from dense forest. Nest tree species selection was non-random, and oil palms were used at a much lower proportion (10%) than previously reported from other study sites in forest-savannah mosaics. While this study suggests that human disturbance may underlie the exclusive arboreal nesting at LCNP, better quantitative data are needed to determine to what extent the construction of elevated nests is in fact a response to predators able to climb trees. Given the importance of LCNP as refuge for Pan t. verus our findings can improve conservation decisions for the management of this important umbrella species as well as its remaining suitable habitats.

Does a sap feeding marsupial choose trees with specific chemical characteristics?

Only about 20 vertebrate species are known to feed regularly on tree sap. One of these is the yellow-bellied glider (Petaurus australis), a marsupial that obtains between 16% and 80% of its diet from eucalypt sap. We reviewed the literature on sap feeding by the yellow-bellied glider and identified 10 species from which it most frequently obtains sap. These species come mainly from a few sections of the subgenus Symphyomyrtus, which accounts for two-thirds of over 2000 sap trees reported, but more specifically sections Latoangulatae and Maidenii within this subgenus. Some of these key species contain relatively high concentrations of foliar nutrients and each is an important food tree for at least one of the arboreal folivores – koala (Phascolarctos cinereus), greater glider (Petauroides volans), and common ringtail (Pseudocheirus peregrinus) and brushtail possums (Trichosurus vulpecula). Because yellow-bellied gliders, like the arboreal folivores, prefer to feed from certain individuals within a species, we hypothesized that these trees possess a unique chemical signature that links sap-feeding with the concentrations of available nitrogen and formylated phloroglucinol compounds in leaves – the nutritive and defensive chemicals that influence feeding on these species by marsupial folivores. We tested this hypothesis in samples of leaves and bark collected from E. punctata and E. viminalis but found no link between chemistry and sap feeding and conclude that other aspects of an individual tree, such as sap flow or sap chemistry, determine whether gliders will target it for sap.

Fine-Scale Habitat Use by Orang-Utans in a Disturbed Peat Swamp Forest, Central Kalimantan, and Implications for Conservation Management

This study was conducted to see how orang-utans (Pongo pygmaeus wurmbii) were coping with fine-scale habitat disturbance in a selectively logged peat swamp forest in Central Kalimantan, Borneo. Seven habitat classes were defined, and orang-utans were found to use all of these, but were selective in their preference for certain classes over others. Overall, the tall forest classes (≥20 m) were preferred. They were preferred for feeding, irrespective of canopy connectivity, whereas classes with a connected canopy (canopy cover ≥75%), irrespective of canopy height, were preferred for resting and nesting, suggesting that tall trees are preferred for feeding and connected canopy for security and protection. The smaller forest classes (≤10 m high) were least preferred and were used mainly for travelling from patch to patch. Thus, selective logging is demonstrated here to be compatible with orang-utan survival as long as large food trees and patches of primary forest remain. Logged forest, therefore, should not automatically be designated as ‘degraded'. These findings have important implications for forest management, forest classification and the designation of protected areas for orang-utan conservation.

Competition for food in a solitarily foraging folivorous primate (Lepilemur leucopus)?

Group-living folivorous primates can experience competition for food, and feeding competition has also been documented for solitarily foraging gummivorous and omnivorous primates. However, little is known about the types and consequences of feeding competition in solitary folivorous foragers. We conducted this study in the spiny forest of Berenty Reserve, southern Madagascar, to characterize the competitive regime of the nocturnal solitarily foraging white-footed sportive lemur (Lepilemur leucopus), a species that lives in dispersed pairs. We analyzed 1,213 hr of behavioral observations recorded simultaneously for the male and female of each of seven social units and recorded seasonal changes in food availability over a complete annual cycle. Lepilemur leucopus exhibited low selectivity in its dietary choice and mainly included the most abundant plant species in its diet. Contrary to our predictions, we did not find evidence for increased rates of contest (i.e., displacement from food trees) or scramble competition (i.e., shared use of food patches) during the lean season, neither within nor between social units. Instead, conflict rates were low throughout the year, and, during these observations, any feeding stress may have been more related to food quality than quantity. The resource defense hypotheses may not explain pair-living in this species as there was no indication that males defend food resources for their female pair-partners. The observed lack of feeding competition may indicate that a cryptic anti-predator strategy is a better predictor of spatial avoidance of pair-partners than conflict over food. While anti-predator benefits of crypsis may explain, at least partly, female-female avoidance, studies on the relationship between territory size/quality and reproductive success are required to understand whether feeding competition reduces the potential for female association in L. leucopus.

Impacts of the diversity of traditional uses and potential economic value on food tree species conservation status: case study of African bush mango trees (Irvingiaceae) in the Dahomey Gap (West Africa)

Background and aims – Bitter and sweet African bush mango trees belong to the family Irvingiaceae and produce valuable non-timber forest products in humid lowland areas of West and Central Africa. The bitter and sweet types are treated as distinct taxa at the variety or species level. They have not been studied in the western part of their distribution range, and many aspects of their large-scale utilization remain unknown. In this study, we link differences in socio-cultural groups to the agroforestry status of bush mango trees in order to identify the key factors influencing their abundance and conservation in the study area. Methods – First, we gathered uses and local management strategies from nine main socio-cultural areas in Benin and Togo, part of the Dahomey Gap. Second, occurrence data were obtained throughout the Gap and imported into DIVA-GIS and MATLAB to calculate the spatial pattern of the density and analyse its structure and variation relative to three factors: the country, the phytogeographical zone and the dominant soil category. Third, agroforestry system characteristics and farmers' social status relative to 841 trees were used in a multinomial logistic regression to identify anthropogenic factors driving the intensive cultivation of bush mango trees. Finally, the impact of socio-cultural activities on extent and density of bush mango tree populations was analysed. Key results – In the entire study zone, the sweet mesocarp is consumed and the endocarp of bush mangoes is commercialized. The application of endocarp-based diets and socio-therapeutic uses are common to communities in Benin. Sweet bush mango trees are generally found either in home gardens or cultivation fields where they may occur at high densities (up to 1020 trees per 25 ha). Bitter trees, however, are confined to the Volta forest region in Togo and occur at low densities (<462 trees per 25 ha) in the wild, sometimes in protected areas, in forest gardens and in fields. This indicates a clear difference in cultivation methods between the bitter and sweet trees. Farmland status, farmer socio-cultural group and type of bush mango trees determined the cultivation intensity. Conclusion – The fact that small farmlands are converted into sweet bush mango tree orchards indicates that farmers actively cultivate bush mango trees in the study area. Diversity of indigenous knowledge, however, is not correlated either to intensive cultivation or domestication efforts and local genetic conservation program. Where slash and burn agriculture and intensive collection of fruits jeopardize bitter trees, traditional fishing systems (using bush mango twigs), a traditional selection strategy, and intensive land commercialization severely threaten sweet bush mango tree genetic resources.

Designing food and habitat trees for urban koalas: graft compatibility, survival and height of tall eucalypt species grafted onto shorter rootstocks

The Corymbia and Eucalyptus species eaten by koalas are generally large trees, but these are often unpopular with urban landowners and councils because of the dangers of limbs falling from a great height. We aimed to develop shorter koala food and habitat trees for urban areas by heterografting tall eucalypt species onto rootstocks of shorter species and comparing their survival and growth with homografted trees and control ungrafted trees. In total, 12 of 14 interspecific scion/rootstock combinations were grafted successfully in the nursery but graft compatibility and field survival depended on taxonomic relatedness. The six interspecific combinations that had multiple surviving trees at 5 years after planting were all between species within the same taxonomic section or between a species and its own interspecific hybrid. Almost all trees died from grafts between species in different taxonomic sections. In most cases, the height of surviving interspecific grafted trees did not differ from control intraspecific grafted trees or from ungrafted trees of their scion species. Grafting elicited a ‘thrive or not survive’ response that diminished its usefulness for producing shorter trees. However, one combination, E. moluccana/E. behriana, had field survival of 40% and reduced height (4.0 m vs 9.9 m). These could be valuable habitat trees for koalas and other fauna in urban areas.

Do Koalas Phascolarctos cinereus use trees planted on farms? A case study from north-west New South Wales, Australia.

Biodiversity benefits are routinely cited as an outcome of planting trees on farms but there has been too little information to properly substantiate such claims. This study is among the first to examine the use of plantings by arboreal mammals. We examined an important inland koala population and its use of farm revegetation to determine: (1) if koalas use planted trees; (2) patch characteristics correlated with use/non-use by koalas; and, (3) contextual characteristics correlated with use/non-use. Surveys of koala dung, also known as scats or faecal pellets, were conducted under trees in 19 plantings. Fourteen showed signs of koalas and their pellets were recorded under 16 of the 25 tree taxa examined. All sizes and ages of trees were used, including the youngest plantings (six years). Considerable koala activity occurred in the various Eucalyptus species, but some tree species were not used. Koalas made substantial use of inland ironbark species, which are not listed as ‘koala food trees’ in government policy documents. Proximity to potential source populations of koalas was the strongest predictor of a planting being used, but this was further improved by including the age of the planting. There is extensive public funding available for restoration and land care activities. This study demonstrates that certain trees rapidly provide koala habitat when planted on farms and that the first priority should be restoring sites in close proximity to known koala populations. Tree species used should include local recognized food trees, as well as ironbarks and non-eucalyptus species that offer shelter.

Effect of 26 Years of Intensively ManagedCarya cathayensisStands on Soil Organic Carbon and Fertility

Chinese hickory (Carya cathayensis), a popular nut food tree species, is mainly distributed in southeastern China. A field study was carried out to investigate the effect of long-term intensive management on fertility of soils under a C. cathayensis forest. Results showed that after 26 years' intensive management, the soil organic carbon (SOC) content of the A and B horizons reduced by 19% and 14%, respectively. The reduced components of SOC are mainly the alkyl C and O-alkyl C, whereas the aromatic C and carbonyl C remain unchanged. The reduction of active organic matter could result in degradation of soil fertility. The pH value of soil in the A horizon had dropped by 0.7 units on average. The concentrations of the major nutrients also showed a decreasing trend. On average the concentrations of total nitrogen (N), phosphorus (P), and potassium (K) of tested soils dropped by 21.8%, 7.6%, and 13.6%, respectively, in the A horizon. To sustain the soil fertility and C. cathayensis production, it is recommended that more organic fertilizers (manures) should be used together with chemical fertilizers. Lime should also be applied to reduce soil acidity.

Dietary quality and tree cover in Africa

The relationship between forests and human nutrition is not yet well understood. A better understanding of this relationship is vital at a time when the majority of new land for agriculture is being cleared from forests. We use Demographic Health Survey data on food consumption for children from 21 African countries and Global Land Cover Facility tree cover data to examine the relationship between tree cover and three key indicators of nutritional quality of children's diets: dietary diversity, fruit and vegetable consumption, and animal source food consumption. Our main findings can be summarized as follows: there is a statistically significant positive relationship between tree cover and dietary diversity; fruit and vegetable consumption increases with tree cover until a peak of 45% tree cover and then declines; and there is no relationship between animal source food consumption and tree cover. Overall our findings suggest that children in Africa who live in areas with more tree cover have more diverse and nutritious diets.

Influence of food availability on the diet and activity budget of two western lowland gorilla (Gorilla gorilla gorilla) groups of differing size in the Dzanga-Ndoki National Park, Central African Republic

Variation in food availability, body size and group size are known to influence primate diet and activity budgets. Here we report how seasonal food availability shapes the diet and activity patterns of two habituated western lowland gorilla (WLG) groups of differing size. WLGs are ripe fruit opportunists, showing dietary flexibility when preferred foods are scarce. However, as fruit can be rare/ patchily distributed, as intra-group feeding competition increases with group size, access to individual patches may be limited. We thus predicted that frugivory decreases with increased group size and influences diet and activity budgets accordingly (increased diet breadth and time feeding since relying on alternative/lower quality food). First, we compared food availability between home-ranges by monitoring leafing/fruiting patterns of major gorilla food trees. Second, we compared the groups’ activity budgets and diet composition/diversity, testing for differences between high (HF) and low fruit seasons (LF). We measured gorilla activity over six months by continuous focal sampling of 16 target animals rotated daily from both groups (N=9 and N=15). Our results confirm that WLG diet consisted mainly of fruits (36%, then: stems 24%; leaves 21%; insects 14%; other food types 3%, and bark 2%) and spend most of their time feeding (39%, then: resting 33%; traveling 19%; social 5%, and other activities 4%). However, contrary to our predictions, we found no group differences within or between seasons: irrespective of group size both spent significantly less time feeding, but more time traveling and socializing, and consumed significantly more fruits, less leaves and bark during the HF compared to the LF. Our results show that WLG activity budgets and diet appear to vary more in response to ripe fruit availability than group size. We suggest that WLGs may cope with increased group size costs through other mechanisms such as group spread, rather than lowering diet quality or further changing activity patterns. Such flexibility may better allow WLG groups to track ripe fruits when available but, unlike sympatric chimpanzees, switch to more herbivorous diets when necessary, adjusting activity budgets accordingly ; WLGs thus may be considered more resilient faced with environmental change such as forest degradation.

Home range areas of koalas in an urban area of north-east New South Wales

Conserving wildlife within urban areas requires knowledge of habitat requirements and population processes, and the management of threatening factors. The koala (Phascolarctos cinereus) is one species that is adversely affected by urban development. Sick and injured koalas in the Lismore urban area are regularly taken into care. We radio-tracked koalas released from care in order to estimate home-range areas and to determine their fate. Koalas were tracked for periods of 90–742 days; 7 of 10 survived for a period of at least one year. Home ranges defined by the minimum convex polygon (MCP100%) were large (mean ± s.e. = 37.4 ± 8.2 ha). Analysis using the 95% Fixed Kernel revealed home-range areas of 8.0 ± 1.7 ha. Analysis of the habitat composition of each MCP home range showed that they included 4.3 ± 0.9 ha of primary habitat (dominated by their primary food trees). These home ranges contained 27.6 ± 6.8 ha of non-habitat (cleared or developed land). Koalas crossed roads within their home ranges at least 5–53 times; one crossed the Bruxner Highway near a roundabout at least 32 times over his 2-year tracking period. Future management should include strategic food tree planting that enhances habitat connectivity and minimises the risk of car strike or dog attack.

Prevalence of Immediate-Type Food Allergy in Early Childhood in Seoul

PurposeThere are scanty epidemiologic data on the prevalence of food allergy (FA) among preschool children in Asia. We performed this study to determine the prevalence and causative foods of immediate-type FA in early childhood in Korea.MethodsA questionnaire-based, cross-sectional study was performed between September and October 2011. Children aged 0-6 years were recruited from 301 public child care centers in Seoul. Parents were asked to complete a questionnaire on FA. Children with FA were classified into "perceived FA, ever," "immediate-type FA, ever," and "immediate-type FA, current" according to the algorithm.ResultsA total of 16,749 children were included in this study. The prevalence of "perceived FA, ever," "immediate-type FA, ever," and "immediate-type FA, current" was 15.1%, 7.0%, and 3.7%, respectively. "Immediate-type FA, current" was reported by 182 (4.9%) out of 3,738 children aged ≤2 years, 262 (3.4%) of 7,648 children aged 3-4 years, and 177 (3.3%) of 5,363 children aged 5-6 years. Hen's egg (126/621) was the most frequent cause as the individual food item, followed by cow's milk (82/621) and peanut (58/621). Among the food groups, fruits (114/621), tree nuts (90/621) and crustaceans (85/621) were the most common offending foods. The three leading causes of food-induced anaphylaxis were hen's egg (22/47), cow's milk (15/47), and peanut (14/47).ConclusionsThe prevalence of immediate-type FA in early childhood is 3.7%, and is higher in younger children. The most common offending foods differed with age.

Local and Landscape Correlates of Primate Distribution and Persistence in the Remnant Lowland Rainforests of the Upper Brahmaputra Valley, Northeastern India

Habitat fragmentation affects species distribution and abundance, and drives extinctions. Escalated tropical deforestation and fragmentation have confined many species populations to habitat remnants. How worthwhile is it to invest scarce resources in conserving habitat remnants within densely settled production landscapes? Are these fragments fated to lose species anyway? If not, do other ecological, anthropogenic, and species-related factors mitigate the effect of fragmentation and offer conservation opportunities? We evaluated, using generalized linear models in an information-theoretic framework, the effect of local- and landscape-scale factors on the richness, abundance, distribution, and local extinction of 6 primate species in 42 lowland tropical rainforest fragments of the Upper Brahmaputra Valley, northeastern India. On average, the forest fragments lost at least one species in the last 30 years but retained half their original species complement. Species richness declined as proportion of habitat lost increased but was not significantly affected by fragment size and isolation. The occurrence of western hoolock gibbon (Hoolock hoolock) and capped langur (Trachypithecus pileatus) in fragments was inversely related to their isolation and loss of habitat, respectively. Fragment area determined stump-tailed (Macaca arctoides) and northern pig-tailed macaque occurrence (Macaca leonina). Assamese macaque (Macaca assamensis) distribution was affected negatively by illegal tree felling, and rhesus macaque (Macaca mulatta) abundance increased as habitat heterogeneity increased. Primate extinction in a fragment was primarily governed by the extent of divergence in its food tree species richness from that in contiguous forests. We suggest the conservation value of these fragments is high because collectively they retained the entire original species pool and individually retained half of it, even a century after fragmentation. Given the extensive habitat and species loss, however, these fragments urgently require protection and active ecological restoration to sustain this rich primate assemblage.

Chimpanzees use long-term spatial memory to monitor large fruit trees and remember feeding experiences across seasons

We studied the nature of information that frugivorous foragers take into account to increase their chances of discovering bountiful fruit crops. We recorded the foraging behaviour of five adult female chimpanzees, Pan troglodytes verus , for continuous periods of 4–8 weeks, totalling 275 full days, throughout multiple fruiting seasons in the Tai National Park, Cote d'Ivoire. We found that chimpanzees fed on individual trees that were significantly larger than other available and reproductively mature trees of the same species, especially if their fruit emitted an obvious smell. Trees that were merely checked for edible fruit, but where monitoring could not have been triggered by olfactory or auditory cues because the tree did not carry fruit, were also significantly larger. Most trees were monitored along the way during travel, but 13% were approached in a goal-directed manner (assessed using a ‘change point test’). These approaches were unlikely to have been initiated by visual cues and occurred more often when females foraged solitarily and when trees were large as opposed to small. Our results suggest that goal-directed monitoring is guided by a long-term ‘what–where’ memory of the location of large potential food sources. These findings were confirmed in a quasiexperiment that tested which of 15 876 potential food trees with different crown sizes were approached in a goal-directed manner. Observations on one female who was followed intensively over 3 consecutive years indicated that monitoring probability was highest for trees with which she had become more familiar through frequent previous visits and that had carried more fruit, suggesting that she was able to remember this information across fruiting seasons. Long-term phenological data on individual trees indicated that the interval between successive fruiting seasons, and hence the ‘memory window’ of chimpanzees required for effective monitoring activities, could be up to 3 years.

Climate‐mediated habitat selection in an arboreal folivore

The decisions that animals must make to achieve a balance between quantity and quality of resources become more difficult when their habitats are patchy and differ greatly in quality across space and time. Koalas are a prime subject to study this problem because they have a specialised diet of eucalypt leaves and need to balance nutrient and water intake against toxins in the leaves, all of which can change with soil type and climate. Koalas are nocturnal and spend most of the day resting and therefore choose trees for reasons other than feeding, particularly for thermoregulation. We GPS‐tracked 40 koalas over 3 yr to determine their shift in tree selection between day and night, and in relation to daily maximum temperature, in a patchy rural landscape in north‐western NSW, Australia. The species, degree of shelter, diameter, height and elevation of each visited tree were recorded. We used generalised linear mixed effects models to compare tree use between day and night and maximum daily temperature. Koalas used more feed‐trees during the night, and more shelter‐trees during the day. They also selected taller trees with more shelter in the day compared with night. As daytime temperatures rose, koalas increasingly selected taller trees at lower elevations. Our results demonstrate that koalas need taller trees, and non‐feed species with shadier/denser foliage, to provide shelter from heat. This highlights the need both for the retention of taller, mature trees, such as remnant paddock trees, and the planting of both food and shelter trees to increase habitat area and connectivity across the landscape for arboreal species. Retaining and planting trees that provide optimum habitat will help arboreal folivores cope with the more frequent droughts and heatwaves expected with climate change.

Is There a Role for Human-Dominated Landscapes in the Long-Term Conservation Management of the Critically Endangered Kipunji (Rungwecebus kipunji)?

As forest loss and degradation continues, the human-dominated landscape outside protected areas should become increasingly relevant to primate conservation. Here we consider the Tanzanian endemic kipunji, Rungwecebus kipunji, whose small extent of occurrence (42 km2) and population (1117 individuals) qualify it for Critically Endangered status on the IUCN Red List. Habitat models suggest there is limited potential for expansion within the kipunji’s current protected forest habitat. In 2010, we examined the potential conservation role of land surrounding the forests using ecological surveys and structured interviews. Land outside protected forest is dominated by subsistence agriculture interspersed with tiny forest patches (almost all <0.4 km2) that cover only 2.4 % of the surveyed area located within 10 km of the forest boundary. Habitat bordering the forest forms a “hard edge” for kipunji, although some sites with single kipunji food trees, e.g., Ficus, offer some potential for use. However, tolerance of kipunji in the agricultural landscape may be limited in areas where kipunji was recorded crop raiding maize along the forest edge, and protection/retaliatory measures are employed. The Bujingijila corridor (2.1 km2) is a priority site for reforestation, particularly in the context of ongoing “Reducing Emissions from Deforestation and Forest Degradation (REDD+)” activities. We recorded the presence of kipunji food trees and little agriculture. Bujingijila could provide habitat for an additional 88 kipunji (8 % population increase), using density estimates from a 2006 census. Bujingijila has the additional benefit of reconnecting the Mt. Rungwe and Livingstone kipunji subpopulations.

The Value of Measuring Food Availability on the Ground for a Semiterrestrial Frugivore, the Tana River Mangabey (Cercocebus galeritus) of Kenya

Collecting phenological data, seasonal availability of plant resources that primates feed on, allows us to understand feeding ecology better. A number of primates are terrestrial or semiterrestrial frugivores, yet phenology is generally measured only in the canopy. I hypothesized that combining measurements of food availability on the ground with canopy measurements would more strongly correlate with diet than canopy measurements alone for a semiterrestrial frugivore, the Tana River mangabey (Cercocebus galeritus). From July 2005 until June 2006, I conducted monthly follows on a mangabey group. Phenology was measured in 105 individuals of their top seven food tree species. I measured canopy phenology on a 0–5 scale and counted fruits in three 1 m3 areas of the canopy, and measured ground phenology by counting fruits and seeds in four 1 m2 quadrats under the canopy. I calculated each tree’s canopy volume and canopy shadow, and each species’ mean fruit weight, mean seed weight, and density. Monthly biomasses were calculated as kilograms per hectare. Spearman correlations were performed between diet contribution and canopy biomass, ground biomass, and total biomass. The hypothesis was not supported for seven species individually or combined. The hypothesis was supported for 3 of 12 diet items, although canopy biomass was also significant for 2 of those items. Two diet items correlated only with ground biomass. Studies of the Tana River mangabey may benefit from measuring ground phenology only for those items eaten exclusively on the ground. Primatologists studying terrestrial or semiterrestrial frugivores should consider feeding height when deciding on phenology methods.

Apes finding ants: Predator–prey dynamics in a chimpanzee habitat in Nigeria

Some chimpanzee populations prey upon army ants, usually with stick tools. However, how their prey's subterranean nesting and nomadic lifestyle influence the apes' harvesting success is still poorly understood. This is particularly true for chimpanzees (Pan troglodytes ellioti) at Gashaka/Nigeria, which consume army ants (Dorylus rubellus) with much higher frequency than at other sites. We assessed various harvesting and search options theoretically available to the apes. For this, we reconstructed annual consumption patterns from feces and compared the physical characteristics of exploited ant nests with those that were not targeted. Repeated exploitation of a discovered nest is viable only in the short term, as disturbed colonies soon moved to a new site. Moreover, monitoring previously occupied nest cavities is uneconomical, as ants hardly ever re-used them. Thus, the apes have to detect new nests regularly, although colony density is relatively low (1 colony/1.3 ha). Surprisingly, visual search cues seem to be of limited importance because the probability of a nest being exploited was independent of its conspicuousness (presence of excavated soil piles, concealing leaf-litter or vegetation). However, chimpanzees preferentially targeted nests in forests or at the base of food trees, that is, where the apes spend relatively more time and/or where ant colony density is highest. Taken together, our findings suggest that, instead of employing a search strategy based on visual cues or spatial memory, chimpanzee predation on army ants contains a considerable opportunistic element.

Introducing urban food forestry: a multifunctional approach to increase food security and provide ecosystem services

We examine the potential role of perennial woody food-producing species (“food trees”) in cities in the context of urban sustainable development and propose a multifunctional approach that combines elements of urban agriculture, urban forestry, and agroforestry into what we call “urban food forestry” (UFF). We used four approaches at different scales to gauge the potential of UFF to enhance urban sustainability and contribute to food security in the context of urbanization and climate change. First, we identified 37 current initiatives based around urban food trees, and analyzed their activities in three categories: planting, mapping, and harvesting, finding that the majority (73 %) only performed one activity, and only 8 % performed all three. Second, we analyzed 30 urban forestry master plans, finding that only 13 % included human food security among their objectives, while 77 % included habitat for wildlife. Third, we used Burlington, Vermont as a case study to quantify the potential fruit yield of publicly accessible open space if planted with Malus domestica (the common apple) under nine different planting and yield scenarios. We found that 108 % of the daily recommended minimum intake of fruit for the entire city’s population could be met under the most ambitious planting scenario, with substantial potential to contribute to food security even under more modest scenarios. Finally, we developed a Climate–Food–Species Matrix of potential food trees appropriate for temperate urban environments as a decision-making tool. We identified a total of 70 species, 30 of which we deemed “highly suitable” for urban food forestry based on their cold hardiness, drought tolerance, and edibility. We conclude that substantial untapped potential exists for urban food forestry to contribute to urban sustainability via increased food security and landscape multifunctionality.