Forest Structure and Support Availability Influence Orangutan Locomotion in Sumatra and Borneo

The influence of habitat structure and support availability on support use is an important aspect of understanding locomotor behavior in arboreal primates. We compared habitat structure and support availability in three orangutan study sites—two on Sumatra (Pongo abelii) in the dry‐lowland forest of Ketambe and peat swamp forest of Suaq Balimbing, and one on Borneo (Pongo pygmaeus wurmbii) in the disturbed peat swamp forest of Sabangau—to better understand orangutan habitat use. Our analysis revealed vast differences in tree and liana density between the three sites. Sabangau had a much higher overall tree density, although both Sumatran sites had a higher density of larger trees. The two peat swamp forests were more similar to each other than to Ketambe, particularly with regard to support availability. Ketambe had a wider variety of supports of different sizes and types, and a higher density of larger lianas than the two peat swamps. Orangutans in all three sites did not differ substantially in terms of their preferred supports, although Sumatran orangutans had a strong tendency to use lianas, not observed in Sabangau. Differences in observed frequencies of locomotor behavior suggest the homogeneous structure of Sabangau limits the locomotor repertoire of orangutans, with high frequencies of fewer behaviors, whereas the wider range of supports in Ketambe appears to have facilitated a more varied locomotor repertoire. There were no differences among age‐sex classes in the use of arboreal pathways in Suaq Balimbing, where orangutans selected larger trees than were typically available. This was less apparent in Sabangau, where orangutans generally used trees in relation to their environmental abundance, reflecting the homogeneous nature of disturbed peat swamp forest. These results demonstrate that forest architecture has an important influence on orangutan locomotion, which may become increasingly important as the structure of orangutan habitat continues to be altered through human disturbance. Am. J. Primatol. 74:1128‐1142, 2012. © 2012 Wiley Periodicals, Inc.     

Plant Community Structure in Tropical Rain Forest Fragments of the Western Ghats,India1

Changes in tree, liana, and understory plant diversity and community composition in five tropical rain forest fragments varying in area (18–2600 ha) and disturbance levels were studied on the Valparai plateau, Western Ghats. Systematic sampling using small quadrats (totaling 4 ha for trees and lianas, 0.16 ha for understory plants) enumerated 312 species in 103 families: 1968 trees (144 species), 2250 lianas (60 species), and 6123 understory plants (108 species). Tree species density, stem density, and basal area were higher in the three larger (> 100 ha) rain forest fragments but were negatively correlated with disturbance scores rather than area per se. Liana species density, stem density, and basal area were higher in moderately disturbed and lower in heavily disturbed fragments than in the three larger fragments. Understory species density was highest in the highly disturbed 18‐ha fragment, due to weedy invasive species occurring with rain forest plants. Nonmetric multidimensional scaling and Mantel tests revealed significant and similar patterns of floristic variation suggesting similar effects of disturbance on community compositional change for the three life‐forms. The five fragments encompassed substantial plant diversity in the regional landscape, harbored at least 70 endemic species (3.21% of the endemic flora of the Western Ghats–Sri Lanka biodiversity hotspot), and supported many endemic and threatened animals. The study indicates the significant conservation value of rain forest fragments in the Western Ghats, signals the need to protect them from further disturbances, and provides useful benchmarks for restoration and monitoring efforts.     

Species composition,diversity, and abundance of lianas in different secondary and primary forests in a subtropical mountainous area,SW China

The species composition, diversity, and abundance of lianas were studied in four secondary forests (a 100-year-old forest, a middle-aged forest, and two younger secondary forests), and compared with an undisturbed primary forest in the Ailao Mountains of subtropical SW China. The results showed that the species composition of lianas differed greatly from the secondary forests to the primary forest, which exhibit early and late-successional species. The abundance of lianas was relatively higher in the two younger and middle-aged secondary forests than in the old-growth secondary and primary forests. However, liana species richness was very limited in the four secondary forests as compared to the primary forest. Root climbers mainly grew in the primary forest, whereas tendril and hook climbers predominated in the four secondary forests, while stem twiners were common in both. The majority of lianas recorded in this study reproduced by animal dispersal, and there was no variation in dispersal modes across the five forest types. A step-wise regression showed that the abundance of small lianas (dbh <4 cm) was positively correlated with the abundance of small- and medium-sized tree stems and negatively correlated with the abundance of large-sized tree stems, whereas there is a strong positive correlation between the abundance of large lianas (dbh ≥4 cm) and large tree stems. Results from the CCA indicate that canopy openness, soil moisture, and average canopy height were the most important factors that influenced the abundance and distribution of lianas.     

Floristic composition and diversity of three swamp forests in northwest Guyana

This paper reviews the floristic composition, vegetation structure, and diversity of three types of swamp forest that cover a considerable part of Guyana's North-West District. Trees, shrubs, lianas, herbs, and hemi-epiphytes were inventoried in three hectare plots: one in Mora forest, one in quackal swamp, and one in manicole swamp. The Mora forest, flooded annually by white water, was dominated by relatively few, large individuals of Mora excelsa. The very dense, thin-stemmed quackal forest, almost permanently flooded by black water, was characterized by Tabebuia insignis and Symphonia globulifera and contained few palms. The somewhat less dense manicole swamp, flooded regularly by brackish water, was distinguished by large numbers of Euterpe oleracea. Although the three swamps showed little overlap in floristic composition and densities of dominant species, they represent some of the lowest diversity forest in the Neotropics, with an -diversity of 7.4 for the Mora forest, 8.2 for the quackal forest and 5.7 for the manicole swamp. When compared with similar vegetation types in the Guiana Shield, the swamp forests in this study show some interesting differences in species composition and density. The wetlands of the North-West District form the last stretch of natural coastline in Guyana and play an important role in the protection of riverine ecosystems. Furthermore, there is commercial potential for the extraction of non-timber forest products from these low-diversity forests. Nevertheless, in prolonged dry periods, large tracts of quackal forest are being burnt to give way to almost treeless, flooded savannas. For these reasons, adequate management and conservation strategies must be developed for the area.     

Liana Abundance,Diversity, and Distribution on Barro Colorado Island,Panama

Lianas are a key component of tropical forests; however, most surveys are too small to accurately quantify liana community composition, diversity, abundance, and spatial distribution – critical components for measuring the contribution of lianas to forest processes. In 2007, we tagged, mapped, measured the diameter, and identified all lianas ≥1 cm rooted in a 50-ha plot on Barro Colorado Island, Panama (BCI). We calculated liana density, basal area, and species richness for both independently rooted lianas and all rooted liana stems (genets plus clones). We compared spatial aggregation patterns of liana and tree species, and among liana species that varied in the amount of clonal reproduction. We also tested whether liana and tree densities have increased on BCI compared to surveys conducted 30-years earlier. This study represents the most comprehensive spatially contiguous sampling of lianas ever conducted and, over the 50 ha area, we found 67,447 rooted liana stems comprising 162 species. Rooted lianas composed nearly 25% of the woody stems (trees and lianas), 35% of woody species richness, and 3% of woody basal area. Lianas were spatially aggregated within the 50-ha plot and the liana species with the highest proportion of clonal stems more spatially aggregated than the least clonal species, possibly indicating clonal stem recruitment following canopy disturbance. Over the past 30 years, liana density increased by 75% for stems ≥1 cm diameter and nearly 140% for stems ≥5 cm diameter, while tree density on BCI decreased 11.5%; a finding consistent with other neotropical forests. Our data confirm that lianas contribute substantially to tropical forest stem density and diversity, they have highly clumped distributions that appear to be driven by clonal stem recruitment into treefall gaps, and they are increasing relative to trees, thus indicating that lianas will play a greater role in the future dynamics of BCI and other neotropical forests.     

Thirteen years of change in trees and lianas in a Gabonese rainforest

Inventories of trees and lianas were performed at a 13-year interval (1979–1992) in an evergreen forest in north-east Gabon. The number of trees decreased while their basal area and species richness increased. In contrast, both the richness and density of lianas decreased. Lianas with active climbing mechanisms were the main types to disappear.     

Plant diversity in sacred forest fragments of Western Ghats: a comparative study of four life forms

The effect of fragmentation on different life forms within tropical forest plant communities is poorly understood. We studied the effect of degree of fragmentation and surrounding matrix on trees, lianas, shrubs and epiphytes in tropical forest fragments of Kodagu, Western Ghats, India. These fragments exist as sacred groves amidst a highly modified agricultural landscape, and have been preserved by the religious sentiments of local communities. Plants were sampled at two sites in continuous forests and 11 forest fragments. A total of 122 species of trees, 29 species of lianas, 60 species of shrubs and 66 species of epiphytes were recorded. Trees exhibited a significant species–area relationship (R ² = 0.74). Richness estimates after controlling for stem density (rarefaction) revealed that observed species–area relationship was not an artefact of passive sampling. Variation in species richness of the other three groups was explained by stem density and structural diversity. Linear distance from the reserve forest did not explain any variation in species richness. All life forms exhibited significant nested pattern. Trees were nested along the area gradient while nestedness in the other three groups showed evidence in support of habitat nestedness. The four life forms thus responded variably to degree of fragmentation. Our study revealed that 74% of the regional diversity for trees was contributed by diversity among plots, highlighting the importance of inter-patch habitat diversity in maintaining the total regional species pool. We conclude that trees alone cannot serve as good indicator for taking appropriate conservation measures to mitigate species loss resulting from habitat fragmentation.     

Seasonal patterns of spatial variation in understory bird assemblages across a mosaic of flooded and unflooded Amazonian forests

We examined seasonal patterns of spatial variation in understory bird assemblages across a mosaic of upland and floodplain forests in central Amazonia, where variation in flooding patterns and floodwater nutrient load shapes a marked spatial heterogeneity in forest structure and composition. Despite great differences in productivity due to flooding by either nutrient-rich “white waters” (várzea) or nutrient-poor “black waters” (igapó), bird assemblages in the two floodplain forest types were relatively similar, showing lower abundances than adjacent upland forests (terra firme) and sharing a set of species that were absent or scarce elsewhere. Species that breed in pensile nests overhanging water were abundant in floodplain forests, whereas species that feed on the ground were generally scarce. Flooding affected assemblage dynamics in floodplain forests, with some influx of ground-dwelling species such as ant-following birds from adjacent upland during the low-water season, and the occupation by riverine and aquatic species such as kingfishers during floods. Spatial configuration influenced the seasonal pattern of assemblage structuring, with movements from terra firme occurring primarily to adjacent igapó forests. No such influx was detected in várzea forests that were farther from terra firme and isolated by wide river channels. Results support the view that habitat heterogeneity created by flooding strongly contributes to maintain diverse vertebrate assemblages in Amazonia forest landscapes, even in the case of largely sedentary species such as understory forest birds. Including both upland and floodplain forests in Amazonia reserves may thus be essential to preserve bird diversity at the landscape scale.     

Tree species composition and diversity gradients in white-water forests across the Amazon Basin

Aim Attention has increasingly been focused on the floristic variation within forests of the Amazon Basin. Variations in species composition and diversity are poorly understood, especially in Amazonian floodplain forests. We investigated tree species composition, richness and α diversity in the Amazonian white‐water (várzea) forest, looking particularly at: (1) the flood‐level gradient, (2) the successional stage (stand age), and (3) the geographical location of the forests. Location Eastern Amazonia, central Amazonia, equatorial western Amazonia and the southern part of western Amazonia. Methods The data originate from 16 permanent várzea forest plots in the central and western Brazilian Amazon and in the northern Bolivian Amazon. In addition, revised species lists of 28 várzea forest inventories from across the Amazon Basin were used. Most important families and species were determined using importance values. Floristic similarity between plots was calculated to detect similarity variations between forest types and over geographical distances. To check for spatial diversity gradients, α diversity (Fisher) of the plots was correlated with stand age, longitudinal and latitudinal plot location, and flood‐level gradient. Results More than 900 flood‐tolerant tree species were recorded, which indicates that Amazonian várzea forests are the most species‐rich floodplain forests worldwide. The most important plant families recorded also dominate most Neotropical upland forests, and c. 31% of the tree species listed also occur in the uplands. Species distribution and diversity varied: (1) on the flood‐level gradient, with a distinct separation between low‐várzea forests and high‐várzea forests, (2) in relation to natural forest succession, with species‐poor forests in early stages of succession and species‐rich forests in later stages, and (3) as a function of geographical distance between sites, indicating an increasing α diversity from eastern to western Amazonia, and simultaneously from the southern part of western Amazonia to equatorial western Amazonia. Main conclusions The east‐to‐west gradient of increasing species diversity in várzea forests reflects the diversity patterns also described for Amazonian terra firme. Despite the fine‐scale geomorphological heterogeneity of the floodplains, and despite high disturbance of the different forest types by sedimentation and erosion, várzea forests are dominated by a high proportion of generalistic, widely distributed tree species. In contrast to high‐várzea forests, where floristic dissimilarity increases significantly with increasing distance between the sites, low‐várzea forests can exhibit high floristic similarity over large geographical distances. The high várzea may be an important transitional zone for lateral immigration of terra firme species to the floodplains, thus contributing to comparatively high species richness. However, long‐distance dispersal of many low‐várzea trees contributes to comparatively low species richness in highly flooded low várzea.     

Tree Phenology in Adjacent Amazonian Flooded and Unflooded Forests1

Most phenological studies to date have taken place in upland forest above the maximum flood level of nearby streams and rivers. In this paper, we examine the phenological patterns of tree assemblages in a large Amazonian forest landscape, including both upland (terra firme) and seasonally flooded (várzea and igapó) forest. The abundance of vegetative and reproductive phenophases was very seasonal in all forests types. Both types of flooded forest were more deciduous than terra firme, shedding most of their leaves during the inundation period. Pulses of new leaves occurred mainly during the dry season in terra firme, whereas those in the two floodplain forests were largely restricted to the end of the inundation period. Flowering was concentrated in the dry season in all forest types and was strongly correlated with the decrease in rainfall. The two floodplain forests concentrated their fruiting peaks during the inundation period, whereas trees in terra firme tended to bear fruits at the onset of the wet season. The results suggest that the phenological patterns of all forest types are largely predictable and that the regular and prolonged seasonal flood pulse is a major determinant of phenological patterns in várzea and igapó, whereas rainfall and solar irradiance appear to be important in terra firme. The three forest types provide a mosaic of food resources that has important implications for the conservation and maintenance of wide‐ranging frugivore populations in Amazonian forests.     

Habitat Selection and Use of Space by Bald-Faced Sakis (Pithecia irrorata) in Southwestern Amazonia: Lessons from a Multiyear, Multigroup Study

Population density and distribution in tropical forest vertebrates are directly linked to patterns of use of space relative to habitat structure and composition. To examine how forest type may explain the ranging behavior and high variance in group density observed within the geographic range of bald-faced saki monkeys (Pithecia irrorata), we monitored habitat use of 5 neighboring focal groups of this species in southwestern Amazonia over 3 yr. To test whether sakis are unflooded (terra firme) forest specialists, we compared home range (HR) use to the corresponding availability of 4 main forest types and quantified HR size and activity budgets as a function of forest type. HR size varied from 16 to 60 ha, and saki population density at this scale (12.5 ± 6.4 SD individuals/km²) was more closely related to forest type than to group size. Although sakis were not obligate habitat specialists, groups clearly avoided bamboo forest and preferred terra firme forest. Terra firme forests were associated with small HRs, intensive use, high HR overlap, and territorial defense, all of which suggest that saki densities will be higher in areas dominated by terra firme forest where large patches of bamboo (Guadua spp.) are absent. The increased desiccation and subsequent forest fires expected in this region from the combined impacts of climate change and human land use potentially threaten the long-term viability of old-growth terra firme forest specialists such as sakis. Regional-scale conservation efforts should ensure that extensive blocks of terra firme forest are protected in areas that remain relatively free of bamboo.     

The effect of altitude,patch size and disturbance on species richness and density of lianas in montane forest patches

The species richness and density of lianas (woody vines) in tropical forests is determined by various abiotic and biotic factors. Factors such as altitude, forest patch size and the degree of forest disturbance are known to exert strong influences on liana species richness and density. We investigated how liana species richness and density were concurrently influenced by altitude (1700–2360 m), forest patch size, forest patch location (edge or interior) and disturbance intensity in the tropical montane evergreen forests, of the Nilgiri and Palni hills, Western Ghats, southern India. All woody lianas (≥1 cm dbh) were enumerated in plots of 30 × 30 m in small, medium and large forest patches, which were located along an altitudinal gradient ranging from 1700 to 2360 m. A total of 1980 individual lianas were recorded, belonging to 45 species, 32 genera and 21 families, from a total sampling area of 13.86 ha (across 154 plots). Liana species richness and density decreased significantly with increasing altitude and increased with increasing forest patch size. Within forest patches, the proportion of forest edge or interior habitat influenced liana distribution and succession especially when compared across the patch size categories. Liana species richness and density also varied along the altitudinal gradient when examined using eco-physiological guilds (i.e. shade tolerance, dispersal mode and climbing mechanism). The species richness and density of lianas within these ecological guilds responded negatively to increasing altitude and positively to increasing patch size and additionally displayed differing sensitivities to forest disturbance. Importantly, the degree of forest disturbance significantly altered the relationship between liana species richness and density to increasing altitude and patches size, and as such is likely the primary influence on liana response to montane forest succession. Our findings suggest that managing forest disturbance in the examined montane forests would assist in conserving local liana diversity across the examined altitudinal range.     

Trees as islands: canopy ant species richness increases with the size of liana‐free trees in a Neotropical forest

The physical characteristics of habitats shape local community structure; a classic example is the positive relationship between the size of insular habitats and species richness. Despite the high density and proximity of tree crowns in forests, trees are insular habitats for some taxa. Specifically, crown isolation (i.e. crown shyness) prevents the movement of small cursorial animals among trees. Here, we tested the hypothesis that the species richness of ants (S_a) in individual, isolated trees embedded within tropical forest canopies increases with tree size. We predicted that this pattern disappears when trees are connected by lianas (woody vines) or when strong interactions among ant species determine tree occupancy. We surveyed the resident ants of 213 tree crowns in lowland tropical forest of Panama. On average, 9.2 (range = 2–20) ant species occupied a single tree crown. Average (± SE) S_a was ca 25% higher in trees with lianas (10.2 ± 0.26) than trees lacking lianas (8.0 ± 0.51). S_a increased with tree size in liana‐free trees (S_a = 10.99A^0.256), but not in trees with lianas. Ant species composition also differed between trees with and without lianas. Specifically, ant species with solitary foragers occurred more frequently in trees with lianas. The mosaic‐like pattern of species co‐occurrence observed in other arboreal ant communities was not found in this forest. Collectively, the results of this study indicate that lianas play an important role in shaping the local community structure of arboreal ants by overcoming the insular nature of tree crowns.     

广西弄岗五桠果叶木姜子群落木质藤本空间格局及其与树种间的关系

木质藤本是生物多样性的重要组成,木质藤本通过影响支持木进而影响群落的结构和功能,但在生物多样性丰富的北热带喀斯特森林中,木质藤本与支持木的关系鲜为人知。以喀斯特季节性雨林的五桠果叶木姜子（Litsea dilleniifolia）群落为研究对象,对木质藤本的密度、分布格局及其与主要树种的关系进行调查研究,分析木质藤本对树木的影响。结果显示：（1）五桠果叶木姜子群落内木质藤本平均密度为0.0913株/m²,木质藤本在0-20m空间尺度整体表现为聚集分布,且随着尺度增大,聚集强度逐渐减弱;不同径级木质藤本在不同尺度上的分布格局不同。（2）木质藤本对不同径级、不同种类、不同聚集强度的支持木选择表现以下体征：随着支持木径级增加,木质藤本攀附的比例和每木藤本数有增加趋势,且木质藤本胸径与支持木胸径呈极显著正相关;附藤率较高的支持木有紫葳科（Bignoniaceae）种类和东京桐（Deutzianthus tonkinensis）,单木附藤数量多的是南方紫金牛（Ardisia thyrsiflora）;物种的聚集强度与附藤率、附藤数量呈负相关。（3）木质藤本的密度与支持木死亡率关系不显著,而物种的附藤率与死亡率呈极显著负相关。以上结果表明,木质藤本密度在原生性喀斯特季节性雨林中并不高,且木质藤本对支持木具有选择性,但其对五桠果叶木姜子群落的死亡率并未产生显著影响。该研究可为喀斯特原生性季节性雨林的物种共存、极小植物种群保育提供理论依据,也可为石漠化区域的植被修复提供科学参考。     

Growth and mortality of trees in Amazonian tropical rain forest in Ecuador

Abstract. Structural changes are analysed in four samples representing 4 ha, two line transects and two hectare plots, of Amazonian tropical lowland rain forest in northern Ecuador. Only trees with a DBH ≥ 10 cm were included. A sample of floodplain forest in Añangu represents the largest turnover found in tropical forests (stand half-life = 23 yr). The line transect and hectare plot both of tierra firme forest in Añangu have the same turnover (37 yr) and were balanced for death and in-growth of both individuals and wood (basal area). The 1-ha tierra firme sample in Cuyabeno had a turnover of 67 yr and was in a growing phase. The floodplain line transect in Añangu was in a phase of structural breakdown. However, the floodplain line transect had the largest growth of basal area per tree (23.4 cm²/yr). The tierra firme samples had a growth of 9.6, 10.1, and 13.6 cm²/yr. Most of the dead trees fell with some uprooting in three of the four samples. However, no significant difference in the distribution of mode of death was found between the four samples. Death was independent of topography and the dead trees were randomly distributed. As the trees grow up they occupy more space and larger trees (DBH ≥ 15 cm) become more uniformly distributed, whereas smaller trees (DBH ≤ 15 cm) were randomly distributed. Our study confirms that plots of 1 ha are not sufficient to include representative samples of different stages of forest structure.     

Life History Traits of Lianas During Tropical Forest Succession

Tropical secondary forests form an important part of the landscape. Understanding functional traits of species that colonize at different points in succession can provide insight into community assembly. Although studies on functional traits during forest succession have focused on trees, lianas (woody vines) also contribute strongly to forest biomass, species richness, and dynamics. We examined life history traits of lianas in a forest chronosequence in Costa Rica to determine which traits vary consistently over succession. We conducted 0.1 ha vegetation inventories in 30 sites. To examine the establishment of young individuals, we only included small lianas (0.5–1.5 cm diameter at 1.3 m height). For each species, we identified seed size, dispersal mode, climbing mode, and whether or not the seedling is self‐supporting. We found a strong axis of variation determined by seed size and seedling growth habit, with early successional communities dominated by small‐seeded species with abiotic dispersal and climbing seedlings, while large‐seeded, animal‐dispersed species with free‐standing seedlings increased in abundance with stand age. Contrary to previous research and theory, we found a decrease in the abundance of stem twiners and no decrease in the abundance of tendril‐climbers during succession. Seed size appears to be a better indicator of liana successional stage than climbing mode. Liana life history traits change predictably over succession, particularly traits related to seedling establishment. Identifying whether these trait differences persist into the growth strategies of mature lianas is an important research goal, with potential ramifications for understanding the impact of lianas during tropical forest succession.     

Geological History,Flora, and Vegetation of Xishuangbanna,Southern Yunnan,China1

Xishuangbanna of southern Yunnan is biogeographically located at a transitional zone from tropical Southeast (SE) Asia to subtropical East Asia, and is at the junction of the Indian and Burmese plates of Gondwana and the Eurasian plate of Laurasia. The flora of the region consists of a recorded 3336 native seed plant species, belonging to 1140 genera in 197 families, among which 83.5 percent are tropical genera and 32.8 percent are endemic to tropical Asia, suggesting a strong affinity to tropical Asian flora. The vegetation of Xishuangbanna is organized into four forest types: tropical rain forest, tropical seasonal moist forest, tropical montane evergreen broad‐leaved forest, and tropical monsoon forest. The tropical rain forest in Xishuangbanna has the same floristic composition of families and genera as some lowland equatorial rain forests in SE Asia, and is dominated (with a few exceptions) by the same families both in species richness and stem dominance. The exceptions include some deciduous trees in the canopy layer, fewer megaphanerophytes and epiphytes, and a higher abundance of lianas and microphyllic plants. We consider the tropical rain forest of Xishuangbanna as a type of tropical Asian rain forest, based on their conspicuous similarities in ecological and floristic characteristics.     

Patterns of liana community diversity and structure in a tropical rainforest reserve,Ghana: effects of human disturbance

Most studies have concluded that liana diversity and structure increase with disturbance. However, a contradictory pattern has emerged recently calling for more research in the area. Liana diversity and structure were investigated in three forest types that differ in disturbance intensity (nondisturbed, moderately disturbed and heavily disturbed forest: NDF, MDF and HDF, respectively) in the Atewa Range Forest Reserve, Ghana. In each forest type, 10 square plots of 0.25 ha were demarcated. Lianas with diameter ≥1 cm located on trees with diameter ≥10 cm were enumerated. A total of 429 individuals representing 40 species, 29 genera and seventeen families were identified in the study. Shannon diversity and species richness of lianas were significantly lower in the HDF (P < 0.05). Liana density and basal area differed significantly across all forest types (P < 0.0001). The importance value index (IVI) of most liana species varied greatly across the forest types. The current study has provided evidence to support the pattern of decreasing liana diversity and structure with disturbance in some tropical forests. Further studies are recommended to gain more understanding of the factors that are responsible for the divergent liana responses to disturbance in tropical forests.     

Primate assemblage structure in Amazonian flooded and unflooded forests

There is considerable variation in primate species richness across neotropical forest sites, and the richest assemblages are found in western Amazonia. Forest type is an important determinant of the patterns of platyrrhine primate diversity, abundance, and biomass. Here we present data on the assemblage structure of primates in adjacent unflooded (terra firme) and seasonally inundated (várzea and igapó) forests in the lower Purús region of central-western Brazilian Amazonia. A line-transect census of 2,026 km in terra firme, 2,309 km in várzea, and 277 km in igapó was conducted. Twelve primate species were recorded from 2,059 primate group sightings. Although terra firme was found to be consistently more species-rich than várzea, the aggregate primate density in terra firme forest was considerably lower than that in the species-poor várzea. Consequently, the total biomass estimate was much higher in várzea compared to either terra firme or igapó forest. Brown capuchin monkeys (Cebus apella) were the most abundant species in terra firme, but were outnumbered by squirrel monkeys (Saimiri cf. ustus) in the várzea. The results suggest that floodplain forest is a crucial complement to terra firme in terms of primate conservation in Amazonian forests.     

Pollination and phenology of flowers in the canopy of two contrasting rain forest types in Amazonia,Colombia

The main objective of this investigation was to study the pollination characteristics of two types of Amazonian rain forest at plant community level. Seasonally inundated forest was compared with upland (tierra firme) forest. The study focused on plant species in the canopy. The pollination spectra show that in both forests most canopy trees and lianas are pollinated by small bees, large bees, butterflies or by small, relatively unspecialized insects. In the upland forest small bees are the most important pollinators (32% of all species of trees and lianas are pollinated by them), whereas large bees are predominant in the floodplain (22%). Other pollinators, like hummingbirds, bats, moths, and beetles are less common (>10%), but always somewhat more important in the flood plain than in the upland forest. Bees are the most common pollinators of epiphytes. In the flood plain forest, flies are also important as epiphyte pollinators (19%), whereas in the upland forest hummingbirds pollinate more epiphytes. The phenological patterns are quite similar in both the upland and the flood plain. We found a peak in flowering in the transition period between the wet and the dry season. Flowering activity was lowest during the wet season. Differentiation in sexual systems was correlated with life form. Dioecy and monoecy were found mostly among tree species. Most species of all life forms though were hermaphroditic. No difference with respect to the relative importance of sexual systems was found between the two forest types.