Fruit Yield,not DBH or Fruit Crown Volume,Correlates with Time Spent Feeding on Fruits by Wild Leontopithecus rosalia

Assessing fruit availability is a critical element in testing hypotheses concerning resource use by frugivores. One method to estimate fruit availability is to measure tree diameter at breast height (DBH) and assume a positive correlation with fruit tree productivity. Our first objective was to test the relationship between DBH and tree productivity. We used as our measures of tree productivity: volume of the fruit bearing region of the tree crown (FBRv) and fruit yield measured as grams of dry fruit matter per fruit bearing region (FBR). Our second objective was to determine if time spent feeding on fruits by golden lion tamarins was correlated with 3 measures of tree productivity within their territories. We define tree productivity within a territory as tree productivity × tree density (fruit tree productivity/ha). We used as our measures of tree productivity/ha: (1) DBH × tree density, (2) fruit yield × tree density, and (3) FBRv × tree density. We measured DBH and FBRv for 17 fruit species commonly eaten by golden lion tamarins in Poço das Antas Reserve, Brazil. We counted fruits in trees and collected fruits to calculate fruit yield. We used measures of tree densities to calculate tree productivity/ha. We found that DBH correlated with fruit yield. The time tamarins spent feeding did not correlate with DBH ( × tree density) or FBRv ( × tree density), but it correlated with fruit yield ( × tree density). Our results emphasize the importance of recording temporal and spatial measures of fruit productivity that are meaningful to the frugivore studied.     

The age of monumental olive trees (Olea europaea) in northeastern Spain

Trees can reach ages that in some cases amount to thousands of years. In the Mediterranean region, olive trees (Olea europaea) have traditionally been considered a particularly long-lived species. The main objective of this study was to assess the age of large olive trees considered to be millenarian and classified as monumental trees in northeastern Spain. We extracted cores of 14 individuals and obtained 8 sections of trees which had already been cut in the area where the largest olive trees in the northeastern Iberian Peninsula are found. The age of the sampled olive trees was assessed by counting the number of annual growth rings. Tree rings did not cross-date well, neither within nor between individuals, but boundaries between likely annual rings were clearly distinct. We found a linear relationship between DBH and tree age (in years) (Age = 2.11 × diameter(cm) + 88.93, R² = 0.80), which was used to estimate the age of unsampled olive trees. The maximum estimated age (627 ± 110 years) is among the greatest ages reported for olive trees around the world (700 years) and among the oldest trees in Mediterranean ecosystems.     

Modified dispersal‐related traits in disjunct populations of bird‐dispersed Frangula alnus (Rhamnaceae): a result of its Quaternary distribution shifts?

Many European tree species survived Pleistocene glaciations in Mediterranean refugia and rapidly recolonized temperate Europe afterwards. Inter‐ and postglacial migration processes are assumed to have catalized evolutionary optimizations of dispersal‐related traits, but up to now empirical evidence is lacking in vertebrate‐dispersed plants. We investigated if south Iberian glacial relict and central European “colonizer” populations of the bird‐dispersed tree Frangula alnus have experienced differentiations of dispersal‐related traits which increase the mobility of northern populations. A comparison of lifetime reproductive strategy, disperser guilds, ripening phenology, and fruit design revealed considerable differences. Compared to south Iberian conspecifics, central European plants were considerably smaller and experienced a highly accelerated generation turnover. In south Iberian populations seed dispersal was carried out almost completely by resident birds which occurred in constant abundances throughout the ripening season. In contrast, central European seeds were dispersed by migrants whose abundances changed considerably during the ripening season. Several bird species were involved in both study areas but rendered different importance for seed dispersal. The fruit ripening pattern was highly asynchronous throughout the ripening season in south Iberia, while central European trees showed a complex ripening sequence which resulted in a significant correlation between fruit abundance and changing disperser availability. Central European fruits were smaller and showed a considerably smaller seed load than south Iberian fruits, thus presumably being more attractive for their small‐sized main dispersers (Sylvia warblers). Chemical analyses revealed significant differences in contents of water, glucose, fructose, proteins, ash. and phenolic compounds. The extensive differentiation of dispersal‐related traits in F. alnus suggests that even weak selective pressures by frugivores may induce evolutionary adjustments of dispersal traits over large time scales. We suggest that the differences we observe today evolved during the species' distribution shifts in the Quaternary.     

Effects of moderate and severe iron deficiency chlorosis on fruit yield, appearance and composition in pear (Pyrus communis L.) and peach (Prunus persica (L.) Batsch)

The effects of different levels of Fe-deficiency chlorosis on the fruit yield, appearance and composition of pear and peach trees grown in field orchards have been studied. The major effect of Fe deficiency in both species was a large yield reduction, even when chlorosis was moderate, associated to decreases in fruit tree load. Fruit size increased with moderate chlorosis in both species and decreased with severe chlorosis in peach. In peach, moderate or severe chlorosis affected uniformly all branches, leading to firmer fruits with higher acidity, total phenolics and carboxylates. This indicates a delayed maturity that can be attributed to a low C-availability for fruits. In Fe-deficient pear trees, the majority of fruits (98%) were on non-chlorotic or moderately chlorotic branches, and fruits were less green and firm with an increased sugars/acids ratio. This indicates an advanced fruit maturity that can be attributed to an increased C-availability for fruits. All chlorosis levels increased within-tree variation in fruit appearance.     

Size and crown shape predict reproductive maturity of Carapa guianensis in upland and floodplain forests in the northeastern Amazon

Comprehending the size distribution within a population and grasping its connection to tree maturation (onset of reproductive phase) is pivotal for formulating sustainable management strategies and conserving numerous tree species. The objective of this study was to compare the structure and probability of fruit production of Carapa guianensis in two types of forest (varzea, or floodplain, vs. terra firme, or upland) in the northeastern Amazon, Brazil. The study was conducted in four permanent plots of 300 × 300 m (two for each type of forest). All individuals ≥10 cm in diameter at breast height (DBH) were mapped and measured for DBH, height, and canopy characteristics (shape and position), and liana infestation. Sixty-seven trees were inventoried in the upland forest and 297 in the floodplain forest. The trees were larger in the upland (33.36 ± 1.84 cm) than in the floodplain (21.92 ± 1.5 cm) and more than half (56%) of the upland trees and more than two thirds (67%) of floodplain trees were reproductive. The minimum diameter for fruit production in the floodplain (10.2 cm of DBH) was more than two times smaller than in the upland (25.5 cm of DBH). The probability of fruit production of a tree of the same size was twice as high in the floodplain compared with the upland, and trees with rounded canopies had a higher probability of fruit production in the upland. Our results showed that the probability of fruit production can be modeled with variables of tree size and canopy shape, and that intrinsic factors of the forests influence the reproductive maturity of C. guianensis which presents greater precocity and productive potential of seeds in the estuarine floodplain forest of the Amazon River.     

Domestication Syndrome in Caimito (<Emphasis Type="Italic">Chrysophyllum cainito</Emphasis> L.): Fruit and Seed Characteristics

Domestication Syndrome in Caimito ( Chrysophyllum cainito L.): Fruit and Seed Characteristics: The process of domestication is understudied and poorly known for many tropical fruit tree crops. The star apple or caimito tree (Chrysophyllum cainito L., Sapotaceae) is cultivated throughout the New World tropics for its edible fruits. We studied this species in central Panama, where it grows wild in tropical moist forests and is also commonly cultivated in backyard gardens. Using fruits collected over two harvest seasons, we tested the hypothesis that cultivated individuals of C. cainito show distinctive fruit and seed characteristics associated with domestication relative to wild types. We found that cultivated fruits were significantly and substantially larger and allocated more to pulp and less to exocarp than wild fruits. The pulp of cultivated fruits was less acidic; also, the pulp had lower concentrations of phenolics and higher concentrations of sugar. The seeds were larger and more numerous and were less defended with phenolics in cultivated than in wild fruits. Discriminant Analysis showed that, among the many significant differences, fruit size and sugar concentration drove the great majority of the variance distinguishing wild from cultivated classes. Variance of pulp phenolics among individuals was significantly higher among wild trees than among cultivated trees, while variance of fruit mass and seed number was significantly higher among cultivated trees. Most traits showed strong correlations between years. Overall, we found a clear signature of a domestication syndrome in the fruits of cultivated caimito in Panama.     

Intratree Variation in Fruit Production and Implications for Primate Foraging

We tested the hypothesis that fruit quantity and quality vary vertically within trees. We quantified intratree fruit production before exploitation by frugivores at different heights in 89 trees from 17 species fed on by primates in Kibale National Park, Uganda. We also conducted a pilot study to determine if the nutritional value of fruit varied within tree crowns. Depending on the species and crown size, we divided tree canopies into 2 or 3 vertical layers. In 2-layered trees, upper crowns produced fruits that were 9.6–30.1% bigger and 0.52–140 times the densities of those from lower crowns, with one exception. Among 2-layered trees, upper crowns produced a mean of 46.9 fruits/m³ (median 12.1), while lower crowns produced a mean of 14.1 fruits/m³ (median 2.5). Among 3-layered trees, upper crowns produced a mean density of 49.9 fruits/m³ (median 12.5), middle crowns a mean of 16.8 fruits/m³ (median 6.6), and lower crowns a mean of 12.8 fruits/m³ (median 1.8). Dry pulp and moisture were systematically greater per fruit in the highest compared to the lowest canopy layers (22.4% and 16.4% respectively in 2-layered trees, 49.7% and 21.8% respectively in 3-layered trees). In 1 tree of Diospyros abyssinica, a pilot nutritional study showed that upper crown ripe fruit contained 41.9% more sugar, 8.4% more crude proteins, and 1.8 times less of the potentially toxic saponin than lower crown ripe fruit, but the result needs to be verified with more individuals and species of trees. We discuss the consequences of intratree variations in fruit production with respect to competition among frugivorous primates.     

Effects of boron fertilization on `Conference' pear tree vigor, nutrition, and fruit yield and storability

The aim of the study was to examine the response of pear (Pyrus communis L.) trees to soil and foliar applications of boron (B). The experiment was carried out during 2000–2001 in a commercial orchard in Central Poland on mature `Conference' pear trees grafted on Pyrus communis var. caucasica seedlings planted at a spacing of 4 × 2.5 m on a sandy loam soil with a low hot water-extractable B status. Annually, foliar sprays with B were applied. (i) before full bloom (at green and white bud stage, and when 1–5% of flowers was at full bloom), (ii) after flowering (at petal fall, and 7 and 14 days after the end of flowering), or (iii) postharvest in fall (approximately 6 weeks before leaf fall). Spray treatments involved application of B at a rate of 0.2 kg ha^–1 in spring or 0.8 kg ha^–1 in fall. Additionally, other trees were supplied with soil-applied B at the bud break stage at a rate of 2 kg ha^–1. Trees untreated with B served as the control. The results revealed that foliar applications of B before full bloom or after harvest increased fruit set and fruit yield. Tree vigor, mean fruit weight, firmness, soluble solids concentration and titratable acidity of fruits at harvest were not affected by B treatments. Foliar B sprays before full bloom or after harvest increased B concentrations in flowers, and both leaves and fruitlets at 40 days after flowering. Only the foliar treatments after flowering and soil fertilization with B increased the content of this microelement in fruit and leaves at 80 and 120 days after full bloom. Foliar B application before full bloom or after harvest increased calcium (Ca) in fruitlets at 40 days after full bloom, in fruit, and in leaves at 80 and 120 days after full bloom. Nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) in plant tissues were not affected by B fertilization. After storage, and also after the ripening period, fruits from the trees sprayed with B before full bloom or after harvest had higher firmness and titratable acidity than those from the control trees. After the ripening period, fruits from the trees sprayed with B before full bloom or after harvest had lower membrane permeability and were less sensitive to internal browning than the control fruits. These findings indicate that prebloom and postharvest B sprays are successful in increasing pear tree yielding and in improving fruit storability under the conditions of low B availability in the soil.     

Foraging ecology of howler monkeys in a cacao (Theobroma cacao) plantation in Comalcalco, Mexico

Recent evidence indicates that primate populations may persist in neotropical fragmented landscapes by using arboreal agroecosystems, which may provide temporary habitats, increased areas of vegetation, and connectivity, among other benefits. However, limited data are available on how primates are able to sustain themselves in such manmade habitats. We report the results of a 9-month-long investigation of the feeding ecology of a troop of howler monkeys (n = 24) that have lived for the past 25 years in a 12-ha cacao plantation in the lowlands of Tabasco, Mexico. A vegetation census indicated the presence of 630 trees (> or =20 cm diameter at breast height (DBH)) of 32 shade species in the plantation. The howlers used 16 plant species (13 of which were trees) as sources of leaves, fruits, and flowers. Five shade tree species (Ficus cotinifolia, Pithecellobium saman, Gliricidia sepium, F. obtusifolia, and Ficus sp.) accounted for slightly over 80% of the total feeding time and 78% of the total number trees (n = 139) used by the howlers, and were consistently used by the howlers from month to month. The howlers spent an average of 51% of their monthly feeding time exploiting young leaves, 29% exploiting mature fruit, and 20% exploiting flowers and other plant items. Monthly consumption of young leaves varied from 23% to 67%, and monthly consumption of ripe fruit varied from 12% to 64%. Differences in the protein-to-fiber ratio of young vs. mature leaves influenced diet selection by the monkeys. The howlers used 8.3 ha of the plantation area, and on average traveled 388 m per day in each month. The howlers preferred tree species whose contribution to the total tree biomass and density was above average for the shade-tree population in the plantation. Given the right conditions of management and protection, shaded arboreal plantations in fragmented landscapes can sustain segments of howler monkey populations for many decades.     

Reduction of Pear Psylla Damage by the Predatory Bug Anthocoris nemoralis (Heteroptera: Anthocoridae): The Importance of Orchard Colonization Time and Neighboring Vegetation

This 5-year field study was aimed at assessing the importance of predatory arthropods in suppressing pear psylla, Cacopsylla bidens (Sulc), and reducing damage caused by psylla in pear orchards in northern Israel. Correlative data suggest that Anthocoris nemoralis (Fabricius) is the only naturally occurring predator in the system that may reduce pear psylla damage; densities of other predacious taxa in the system (Araneidae, Orius spp., Chrysopidae and Coccinellidae) were not correlated significantly with psylla numbers in the orchards. However, A. nemoralis entered pear orchards at least a month after the beginning of pear psylla activity, apparently too late to prevent fruit damage. Data suggest that A. nemoralis reproduction is lower on both wild and cultivated pears than on Rhamnus, Laurus and Pistacia trees in nearby woods. Furthermore, A. nemoralis populations build up on the wild trees in March, but appear in orchards only in late May. We propose that planting R. alaternus trees near pear orchards could enhance the level of biological control of pear psylla by A. nemoralis. Preliminary results indeed show that pear psylla densities were lower on pear trees grown near Rhamnus alaternus trees than on distant trees.     

Instant domestication process of European chestnut cultivars

This study presents the results of the first genetic analysis of ancient chestnut trees (Castanea sativa Mill.) in Italy and in the Iberian Peninsula to better understand the effect of grafting on the domestication process of chestnut and to investigate the impacts of early selection and improvement on the genetic diversity retained. We evaluated 105 giant ancient trees from Italy, Spain and Portugal and compared them with the European Union (EU) database of chestnut cultivars by using a set of 24 simple sequence repeats (SSRs; microsatellite markers). We measured the perimeter (girth) at the diameter at breast height (DBH). Samples from both the canopy and the roots of each tree were analysed to distinguish which trees were self‐rooted and which were grafted. Diversity was compared using standard metrics and model‐based approaches based on the expected heterozygosity (He) at equilibrium. We could differentiate 91 new genotypes; 9.6% matched known chestnut cultivars. We found the first evidences of cultivation, that is, grafting to produce “instant domestication” in Galicia and in the Douro Valley in trees of 14‐m perimeter (15th century) and in the Basque Country (first report in that area) in a tree of 11.5‐m perimeter (16th century). In Italy, the cultivar “Marrone Fiorentino” was found in some giant trees with perimeters of 8 and 9 m (17th‐18th centuries) in the Toscana and Umbria. Those findings matched with written references in Portugal from the 16th century and from the 18th century in Spain. “Instant domestication” could be dated back to the 15th century and was related to the wild populations existing in the same areas where cultivars are being propagated, without a different genetic structure for wild chestnut trees and with a high diversity maintained through the initiation of domestication.     

Impacts of El Niño related drought and forest fires on sun bear fruit resources in lowland dipterocarp forest of East Borneo

Droughts and forest fires, induced by the El Niño/Southern Oscillation (ENSO) event, have increased considerably over the last decades affecting millions of hectares of rainforest. We investigated the effects of the 1997–1998 forest fires and drought, associated with an exceptionally severe ENSO event, on fruit species important in the diet of Malayan sun bears (Helarctos malayanus) in lowland dipterocarp forest, East Kalimantan, Indonesian Borneo. Densities of sun bear fruit trees (≥10 cm DBH) were reduced by ～80%, from 167±41 (SD) fruit trees ha^?1 in unburned forest to 37±18 fruit trees ha^?1 in burned forest. Densities of hemi-epiphytic figs, one of the main fallback resources for sun bears during periods of food scarcity, declined by 95% in burned forest. Species diversity of sun bear food trees decreased by 44% in burned forest. Drought also affected sun bear fruit trees in unburned primary forest, with elevated mortality rates for the duration of 2 years, returning to levels reported as normal in region in the third year after the ENSO event. Mortality in unburned forest near the burn-edge was higher (25±5% of trees ≥10 cm DBH dead) than in the forest interior (14±5% of trees), indicating possible edge effects. Combined effects of fire and drought in burned primary forest resulted in an overall tree mortality of 78±11% (≥10 cm DBH) 33 months after the fire event. Disturbance due to fires has resulted in a serious decline of fruit resources for sun bears and, due to the scale of fire damage, in a serious decline of prime sun bear habitat. Recovery of sun bear populations in these burned-over forests will depend on regeneration of the forest, its future species composition, and efforts to prevent subsequent fire events.     

Resource patch size and flexible foraging in white-faced capuchins (Cebus capucinus)

White-faced capuchins (Cebus capucinus)on Barro Colorado Island, Panama, have a flexible foraging strategy. Typically, foraging party size is small and individuals feed dispersed from one another. When seasonal fruiting of large volume trees occurs, the majority of the group forages simultaneously. As C. capucinusdo not display a rigorous dominance structure and there are few indications that individuals or coalitions monopolize food patches,individuals are expected to display scramble strategies instead of high frequencies of contest competition. I recorded foraging party size (simultaneous foragers), the total number of animals to feed successively, and the diameter at breast height (DBH) of fruit trees used in two habituated troops. Individuals in each group spent a substantial amount of time — 65 and 48% of foraging time for each group — foraging in party sizes of one. Monkeys predominantly foraged alone in small trees (0- to 20- cm DBH), successively in medium trees (21- to 60- cm DBH), and simultaneously in large trees (>61- cm DBH). They used small trees more frequently than all other tree classes. In medium-sized trees, although fruit was plentiful, space was limited. In these trees Cebusforaged successively. In large-volume trees, space and fruit were abundant and several individuals fed together. As the DBH of fruiting trees increased, the average foraging party size increased exponentially. Cebus capucinusat Barro Colorado Island modify their foraging party size to adapt to the seasonal patterns of fruit production.     

珍稀植物蒜头果野生植株结实量及果实特征研究

该研究对云南省广南县不同分布点的野生植株大小与结实量,果实、果核性状特征,果皮与果核性状间的关系进行了分析。结果表明:(1)野生成年植株个体间结实量差异大,单株结实量从几十个至几千个,变异系数可达136.38%。结实量与冠幅有正相关关系(R=0.592,P0.01),与胸径和树高无相关关系(P0.05)。(2)扁球型果实平均纵径37.10~40.36 mm,变异系数7.28%~8.65%;平均横径41.15~45.03mm,变异系数6.44%~9.31%;平均果实重量35.77~47.29 g,变异系数18.99%~21.44%。野生蒜头果果实大小差异明显,单个果实重量差别为3.4倍。(3)果核平均纵径27.50~31.69 mm,变异系数7.13%~10.99%;平均横径30.94~34.16 mm,变异系数6.47%~9.41%;平均果核重量14.03~18.77 g,变异系数17.37%~22.68%。单个果核重量差别为3.7倍。(4)平均果皮纵向厚度4.33~4.80 mm,变异系数20.22%~26.91%;平均横向厚度5.10~5.44 mm,变异系数12.92%~20.98%;平均果皮重21.62~28.51 g,变异系数20.01%~24.12%。该研究结果表明野生蒜头果单株结实量、果实和果核大小、果皮厚等表型性状存在广泛的多样性,其资源为人工定向培育和开发利用提供了较为丰富的选择材料。     

Round and large: morphological and genetic consequences of artificial selection on the gourd tree Crescentia cujete by the Maya of the Yucatan Peninsula, Mexico

Background and Aims

Artificial selection, the main driving force of domestication, depends on human perception of intraspecific variation and operates through management practices that drive morphological and genetic divergences with respect to wild populations. This study analysed the recognition of varieties of Crescentia cujete by Maya people in relation to preferred plant characters and documents ongoing processes of artificial selection influencing differential chloroplast DNA haplotype distribution in sympatric wild and home-garden populations.

Methods

Fifty-three home gardens in seven villages (93 trees) and two putative wild populations (43 trees) were sampled. Through semi-structured interviews we documented the nomenclature of varieties, their distinctive characters, provenance, frequency and management. Phenotypic divergence of fruits was assessed with morphometric analyses. Genetic analyses were performed through five cpDNA microsatellites.

Key Results

The Maya recognize two generic (wild/domesticated) and two specific domesticated (white/green) varieties of Crescentia cujete. In home gardens, most trees (68 %) were from domesticated varieties while some wild individuals (32 %) were tolerated. Cultivation involves mainly vegetative propagation (76 %). Domesticated fruits were significantly rounder, larger and with thicker pericarp than wild fruits. Haplotype A was dominant in home gardens (76 %) but absent in wild populations. Haplotypes B–F were found common in the wild but at low frequency (24 %) in home gardens.

Conclusions

The gourd tree is managed through clonal and sexual propagules, fruit form and size being the main targets of artificial selection. Domesticated varieties belong to a lineage preserved by vegetative propagation but propagation by seeds and tolerance of spontaneous trees favour gene flow from wild populations. Five mutational steps between haplotypes A and D suggest that domesticated germplasm has been introduced to the region. The close relationship between Maya nomenclature and artificial selection has maintained the morphological and haplotypic identity (probably for centuries) of domesticated Crescentia despite gene flow from wild populations.     

梨枣在果实生长期对土壤水势的响应

以4年生梨枣为试验材料,在果实生长期设置了4个土壤水势水平,研究不同处理梨枣茎秆直径生长、光合速率、蒸腾速率、叶片相对含水量以及果实数量对土壤水势的响应,探讨了梨枣果实生长期适宜的土壤水势范围。结果表明:1)在果实缓慢生长期,茎秆直径生长缓慢;土壤水势高于-84 kPa时能显著地降低落果率。2)果实快速生长期,茎秆直径日最大值和叶片相对含水量能反映梨枣的水分状况;适当的控制土壤水势能显著的提高叶片的水分利用效率;土壤水势高于-84 kPa时果实快速生长期出现坐果现象。3)果实生长期前期的土壤水势低至-461 kPa会影响果实生长期叶片的功能和后期的坐果。因此,梨枣果实生长期的适宜的土壤水势范围为-41—-84 kPa,提高了叶片水分利用效率,提高了单果重,不影响产量。     

Small fruit problem in Citrus trees

Summary Physiological causes of the small fruit problem which occurs in certain trees of orange [Citrus sinensis (L.) Osbeck cv. Valencia] were investigated in terms of water relations and gas exchange of fruits during early fruit development as well as tree carbohydrate reserves. These data from cv. Valencia trees with and without a small fruit potential were compared with those of the large fruited cv. Navel. Neither fruit water potential nor fruit transpiration nor tree carbohydrate reserves appeared to be a cause of the small fruit. Yield records showed the small fruit to be assocaited with a large number of fruit per tree. However, fruits from cv. Valencia trees with a small fruit potential respired faster than either fruits of the same cultivar and size from trees without the physiological disorder or fruits of the same size of cv. Navel and also exceeded the dark respiration of the respective leaves. Hence, the small fruit problem in cv. Valencia was partly attributed to inefficient fruit photosynthesis, causing excessive respiration of each of a larger number of fruits compared to fruits of a tree of the same cultivar but without the physiological disorder. Fruits of cv. Valencia respired more in their 2 months longer lifetime on the tree relative to those of cv. Navel. It is concluded that orchard management methods will have to be investigated to balance the fruit load of the cv. Valencia tree utilizing the carbon available for fruit growth and to minimise stress during the early fruit development.     

Forest association and phenology of wild coffee in Kibale National Park, Uganda

A study on the forest association and phenology of wild coffee ( Coffea canephora Pierre) was conducted in Kibale forest, Uganda. Nested quadrats were used to enumerate tree species, including coffee and herbaceous plants associated with forest and coffee stands. A total of 150 coffee trees was marked along transects and monthly scans carried out to score for fruits, flowers, leaves and leaf insect damage. Pre- and post-dispersal predation levels and coffee yield estimates were made by examining fruits from trees, forest floor and seasonal fruit falls into demarcated plots. In the forest, wild coffee stands are associated with low-quality forest types in terms of timber species (about 10.5 canopy species/study site) and low stocking densities of trees ≥ 50 cm d.b.h. (average 38 trees ha⁻¹ for each site) and poor forest regeneration. In the forest, wild coffee reproductive phases overlap with ripening, coinciding with flower bud and flower production. The variable peak ripening season falls between November and April. The wild coffee yields are generally low (average of 3.5 intact fruits 16 m⁻² month⁻¹), with low insect fruit/seed damage (4–19%) but high levels of wastage due to monkeys, bats and birds.     

Fruit size and shape: Allometry at different taxonomic levels in bird-dispersed plants

Summary The likelihood that a plant's seeds will be dispersed by fruit-eating birds may depend upon the size and shape of its fruits. Assuming that elongate fruits can be swallowed more easily than spherical fruits of equal volume and that plant fitness is enhanced by seed dispersal by many individuals and species of birds, natural selection should favour increasing fruit elongation with increasing fruit size in bird-dispersed plants. According to this view, this allometric pattern would be adaptive. Alternatively, fruit shape in bird-dispersed plants may be constrained by development or phylogeny. To determine whether there was any evidence to support the adaptive allometry hypothesis, we examined allometric relationships between length and diameter in fruits and seeds in a group of neotropical bird-dispersed plant species. Using the major axis technique, we regressed ln(diameter) on ln(length) for fruits and seeds at various taxonomic levels: (1) within individual trees ofOcotea tenera (Lauraceae) (2) among 19 trees within a population ofO. tenera, as well as among pooled fruits from multiple trees within 20 other species in the Lauraceae, (3) among 25 sympatric species within a plant family (Lauraceae) and (4) among 167 species representing 63 angiosperm families within a plant community in Monteverde, Costa Rica. At most taxonomic levels, a tendency for fruit length to increase more rapidly than fruit diameter among fruits (negative allometry) occurred more frequently than expected by chance. Estimated slopes of the regressions of fruit length on fruit diameter were < 1 within 15 of the 19 individualO. tenera trees, among tree means withinO. tenera, among pooled fruits within 16 of the 20 other species in the Lauraceae, among species means within the Lauraceae and among means of all bird-dispersed species in the lower montane forests of Monteverde. Seed allometry showed similar patterns, although for both fruits and seeds the broad confidence intervals of the slopes estimated by major axis regression overlapped 1 in many cases. Among the 63 Monteverde family means, fruit length and diameter scaled isometrically. Based on measurements of ontogenetic changes in fruit shape in a single species,O. viridifolia, we found no evidence that negative allometry in fruit shape within the Lauraceae was an inevitable consequence of developmental constraints. Instead, increasing elongation of fruits and seeds in certain plant taxa is consistent with adaptation to gape-limited avian seed dispersers. Contrary results from vertebrate-dispersed species from Malawi and Spain may reflect differences between the New and Old World in plant taxa, seed dispersers or evolutionary history.