Diversity and composition of larger moths in three different forest types of Southern Korea

Moth assemblages in three habitat types were investigated to find differences in species richness and abundances and to find any specific moth group(s) in each habitat. Study areas were in southern Korea: lowlands of Muan-county, Jeollanam-do Province and mid-elevations to highlands of Mt. Jirisan National Park. Moth monitoring, conducted at eight sites, was comprised of three habitat types—native forest, regenerative forest and rural landscape. A total of 4,803 individuals, consisting of 583 species in 362 genera, were identified. Species richness did not differ significantly by habitat type or elevation. ANOVA indicated that site, location and elevation significantly affected the species abundances of Drepanidae, Epiplemidae, Limacodidae, Noctuidae and Zygaenidae, while habitat type was not a significant factor. The moth abundances of Geometridae, Lasiocampidae, Lymantriidae, Notodontidae, Saturniidae, Sphingidae and Thyatiridae were not significantly associated with any independent variables. The diversity patterns of larger moths along environmental gradients and the relationship between moths and forest types were discussed.     

A hawkmoth crossroads? Species richness,seasonality and biogeographical affinities of Sphingidae in a Brazilian Cerrado

Aim The aim of the study was (1) to describe the biodiversity of the sphingid assemblage in a Cerrado area in the Triângulo Mineiro region, south‐east of Brazil; (2) to evaluate the seasonal variations in species composition; (3) to compare the faunistic relationships between the Cerrado biome and adjacent ecosystems; and (4) to analyse the biogeographical pattern of species distribution in the Neotropical region in a historical context. Location Panga Ecological Station (PES), 30 km south of the city of Uberlândia, and other areas of the Triângulo Mineiro region, Minas Gerais state, south‐eastern Brazil. Methods Moth richness and abundance were monitored monthly at the PES from August 2003 to July 2004, with additional collections at this locality in 2001/2002, 2005 and 2006. Complementary moth richness and abundance data were also collected in other areas of the Triângulo Mineiro region. All collections were made using light traps, and the hawkmoths were mounted and identified. Cluster analysis, rarefaction curves and estimators of total species richness were used to compare the Cerrado hawkmoth assemblage with assemblages derived from other surveys in the Neotropics. Results In total, 61 hawkmoth species were recorded for the study region and their occurrence was markedly seasonal. The hawkmoth assemblage in the study area presented the closest similarity with rain forest areas and with a tropical dry forest area in Central America. The area shared species with both rain forest and seasonally dry tropical forest (SDTF) ecosystems, including supposedly endemic species previously recorded only in the latter areas. Rarefaction curves and estimators of the total number of species showed species richness to be comparable with other highly diverse forest areas in the Neotropics, such as the Brazilian Amazon and Costa Rica. Main conclusions This short‐term study is the first systematic survey of hawkmoths in the Cerrado. It has recorded around 22% of the South American fauna and highlighted the high species richness of the region, which compares favourably with that in other rain forest ecosystems. The survey indicates high regional diversity, and has shown that the Cerrado harbours a hawkmoth fauna comprising both rain forest elements, probably distributed along humid gallery forest corridors, and SDTF elements, supporting the idea of a historical Pleistocene arc connecting the Caatinga domain and other seasonal dry forest areas across the Cerrado region.     

Determinants of nocturnal Lepidopteran diversity and community structure in a conifer-dominated forest

Prediction of community response of fauna to anthropogenic or environmental disturbance requires knowledge of faunal distribution and abundance as well as an understanding of the mechanisms underlying community organization. We investigated linkages between Lepidoptera, one of the most influential insect taxa in forested ecosystems, and vegetation in riparian areas of conifer-dominated forests of western Oregon, USA. Using model selection techniques, we found that canopy cover explained variability in patterns of moth species dominance and diversity better than all other factors investigated, whereas elevation best explained patterns of moth species richness. Using canonical correspondence analysis, we determined that gradients in shrub species richness, elevation, and understory species richness accounted for the most variation in regional moth community structure. Results suggest that reductions of riparian forest canopy are likely to have the greatest impact on the variety and relative abundance of moths. Due to the relative rarity and patchy distribution of the majority of individual species, we predict that lower intensity vegetation manipulations distributed across larger spatial scales are likely to be less damaging to regional moth biodiversity than more intensive alterations at smaller scales. Finally, if global warming trends continue, upward elevational shifts in moth species distributions will make forested regions at higher elevation worthy of concerted protection.     

Contrasting effects of habitat quantity and quality on moth communities in fragmented landscapes

Habitat loss is commonly identified as a major threat to the loss of global biodiversity. In this study, we expand on our previous work by addressing the question of how lepidopteran species richness and composition vary among remnants of North American eastern deciduous forest located within agricultural or pastoral landscapes. Specifically, we tested the relative roles of habitat quantity (measured as stand area and percent forest in the greater landscape) and habitat quality (measured as tree species diversity) as determinants of moth species richness. We sampled >19 000 individuals comprising 493 moth species from 21 forest sites in two forested ecoregions. In the unglaciated Western Allegheny Plateau, the species richness of moths with woody host plants diminished as forest stand size and percent forest in the landscape decreased, but the total species richness and abundance of moths were unaffected by stand size, percent forest in the landscape, or tree species diversity. In contrast, the overall species richness and abundance of moths in the glaciated North Central Tillplain were affected primarily by tree species diversity and secondarily by forest size. Higher tree species diversity may reduce species loss from smaller forest stands, suggesting that small, diverse forests can support comparable numbers of species to those in less diverse, large stands. Smaller forests, however, contained a disproportionate number of moth species that possess larvae known to feed on herbaceous vegetation. Thus, although woody plant feeding moths are lost from forests with changes in stand area, new species appear capable of recolonizing smaller fragments from the surrounding habitat matrix. Our study further suggests that when species replacement occurs, local patch size and habitat quality may be more important than landscape context in determining the community structure of forest Lepidoptera.     

Beta diversity and oligarchic dominance in the tropical forests of Southern Costa Rica

Recent studies have reported a consistent pattern of strong dominance of a small subset of tree species in neotropical forests. These species have been called “hyperdominant” at large geographical scales and “oligarchs” at regional‐landscape scales when being abundant and frequent. Forest community assembly is shaped by environmental factors and stochastic processes, but so far the contribution of oligarchic species to the variation of community composition (i.e., beta diversity) remains poorly known. To that end, we established 20.1‐ha plots, that is, five sites with four forest types (ridge, slope and ravine primary forest, and secondary forest) per site, in humid lowland tropical forests of southwestern Costa Rica to (a) investigate how community composition responds to differences in topography, successional stage, and distance among plots for different groups of species (all, oligarch, common and rare/very rare species) and (b) identify oligarch species characterizing changes in community composition among forest types. From a total of 485 species of trees, lianas and palms recorded in this study only 27 species (i.e., 6%) were nominated as oligarch species. Oligarch species accounted for 37% of all recorded individuals and were present in at least half of the plots. Plant community composition significantly differed among forest types, thus contributing to beta diversity at the landscape scale. Oligarch species was the component best explained by geographical and topographic variables, allowing a confident characterization of the beta diversity among tropical lowland forest stands. Abstract in Spanish is available with online material.     

Temporal patterns in Saturnidae (silk moth) and Sphingidae (hawk moth) assemblages in protected forests of central Uganda

Forest‐dependent biodiversity is threatened throughout the tropics by habitat loss and land‐use intensification of the matrix habitats. We resampled historic data on two moth families, known to play central roles in many ecosystem processes, to evaluate temporal changes in species richness and community structure in three protected forests in central Uganda in a rapidly changing matrix. Our results show some significant declines in the moth species richness and the relative abundance and richness of forest‐dependent species over the last 20–40 years. The observed changes in species richness and composition among different forests, ecological types, and moth groups highlight the need to repeatedly monitor biodiversity even within protected and relatively intact forests.     

西双版纳片段化石灰岩森林附生兰科植物多样性研究

西双版纳石灰岩地区拥有丰富的兰科植物资源,但近年来随着橡胶树的大面积种植,使得该地区很多石灰岩森林呈片段化。为了解片段化石灰岩森林中附生兰科植物多样性状况以及片段化对附生兰科植物的影响,该研究选取了生境片段化的青岩寨和曼纳览,以及连续生境的绿石林和巴卡新寨等4个样地的29个样方进行多样性调查和对比研究。结果表明:4个石灰岩森林样共记录到附生兰科植物34属76种1 528株(丛)。通过对坡向、坡度、海拔、地形、郁闭度和森林类型等6个环境因子与附生兰科植物丰富度进行CCA分析,发现石灰岩地区附生兰科植物的分布主要受海拔和森林类型2个因素的影响,在海拔较高的青岩寨和巴卡新寨附生兰科植物物种丰富度高于低海拔的绿石林和曼纳览,而片段化对附生兰科植物的物种多样性和多度均无显著影响,这可能与片段化的历史较短有关。虽然目前来看生境片段化对石灰岩地区的附生兰科植物多样性无显著影响,但生境脆弱的石灰岩森林植被的保护对于兰科植物多样性保护则更具重要性。     

Ecological and biogeographical studies on the tropical rain forest of south Yunnan,SW China with a special reference to its relation with rain forests of tropical Asia

Abstract. Ecological and biogeographic analyses of the tropical rain forest in south Yunnan were made using data from seventeen sample plots and floristic inventories of about 1000 species of seed plants. The rain forest is shown to be a type of true tropical rain forest because it has almost the same profile, physiognomic characteristics, species richness per unit area, numbers of individuals in each tree species and diameter classes of trees as classic lowland tropical rain forests. As the area is at the northern margin of monsoonal tropics, the rain forest differs from equatorial lowland rain forests in having some deciduous trees in the canopy layer, fewer megaphanaerophytes and epiphytes but more species of lianas as well as more species of microphylls. In its floristic composition, about 80% of total families. 94% of total genera and more than 90% of total species are tropical, of which about 38% of genera and 74% of species are tropical Asian. Furthermore, the rain forest has not only almost the same families and genera, but also the same families rank in the top ten both in species richness and in dominance of stems, as lowland forests in southeast Asia. It is indisputable that the flora of the rain forest is part of the tropical Asian flora. However, most of the tropical families and genera have their northern limits in south Yunnan and most have their centre of species diversity in Malesia. More strictly tropical families and genera have relatively lower species richness and importance compared with lowland rain forests in tropical southeast Asia. Thus, the flora also shows characteristics of being at the margin of the tropics. Based mainly on physiognomy and floristic composition the tropical rain forest of Yunnan is classified into two types, i.e. seasonal rain forest and wet seasonal rain forest, the latter is further divided into two subtypes, i.e. mixed rain forest and dipterocarp rain forest. From analysis of geographic elements it is also shown that the tropical rain forest of Yunnan occurs at a geographical nexus with its flora coming mainly from four sources, i.e. Malesia, south Himalayas, Indochina and China.     

Contrasting patterns of vertical stratification in two moth families in a Costa Rican lowland rain forest

The vertical stratification of two species-rich moth families (Lepidoptera: Arctiidae, Geometridae) was analysed in a lowland rain forest in Costa Rica. Moths were trapped with automatic 8 W ultraviolet light traps at three sites in the understorey and canopy of a primary forest at the La Selva Biological Station (10.4° N, 84.0° W). A total of 846 arctiid moths (148 species) and 946 geometrid moths (140 species) were analysed. Species richness and diversity of arctiid moths was significantly lower in the understorey than in the canopy (Fisher's alpha: 24 vs. 49) whereas geometrid moths showed an inverse pattern (Fisher's alpha: 44 vs. 27). This resulted in an overall increase in the proportion of conspicuously coloured species towards the canopy. Moth ensembles were clearly separated in multidimensional scaling ordinations, and differed significantly in their faunal composition and dominance between the strata. The available host plant data suggest that the flight height of moths was determined by larval resource availability. Examples include understorey flyers such as the geometrid genus Eois feeding on Piper, and canopy flyers such as the arctiid moth genera Aclytia, Macrocneme and Poliopastea which feed on lianas.     

滇南热带雨林物种多样性的取样面积探讨

通过不同面积样方种数的比较、物种多样性指数等的计算和逐步扩大样地面积的调查, 本文研究了滇南热带雨林种数/面积关系、个体/种数关系、物种多样性及树种的频度分布规律, 认为滇南热带雨林群落学调查的最适取样(样方)面积是0.25 hm², 这个面积接近该类型热带雨林理论上的群落最小表现面积。 为能体现一个具体森林(群落)类型的基本的植物区系组成, 需设置4～5个这样的样方(总面积累计1 hm²以上)。从与世界不同地区热带雨林的比较亦可见,云南热带雨林有类似的树种频度分布规律,单位面积上的物种多样性比典型的东南亚低地热带雨林稍低,但比非洲的热带雨林要高。     

海南岛霸王岭两种典型热带季雨林群落特征

热带季雨林为海南岛的隐域性植被类型,分布在与热带低地雨林相似的海拔范围但生境条件较差的局部地段,在旱季其大部分的乔木种类和个体都会落叶.海南岛霸王岭林区分布着海南岛最为典型且大都保存较为完好的热带季雨林原始林,按照其优势树种可划分为海南榄仁(Terminalia hainanensis)季雨林和枫香(Liquidambar formosana)季雨林两种群落类型.通过对霸王岭林区两种典型的热带季雨林老龄林群落的样地调查,比较分析了其物种组成、大小结构、多样性、季相变化等特征.结果表明:海南岛热带季雨林群落中物种优势度明显,具有明显的标志种--海南榄仁和枫香.海南榄仁群落具有较高的灌木物种丰富度、个体多度及较低的乔木物种丰富度、个体多度和多样性;海南榄仁群落在小径级和低高度级中具有较高的植物个体多度,同时在低高度级中具有较低的物种丰富度,但其它径级和高度级两个群落物种丰富度及个体多度差异均不显著;除灌木落叶物种丰富度海南榄仁群落显著高于枫香群落外,其余各生长型落叶物种丰富度及个体多度两个群落之间均无显著差异;在具刺木质藤本物种丰富度和个体多度上海南榄仁群落与枫香群落差异不显著,但乔木、灌木和木本植物具刺物种丰富度及个体多度海南榄仁群落均显著高于枫香群落.总体来看,海南榄仁群落比枫香群落的季雨林特征明显,是海南岛最为典型的季雨林群落类型.     

Tiger-Moths in Savannas in Eastern Amazon: First Assessment of Diversity and Seasonal Aspects

Biodiversity knowledge on insects is urgently needed due to the ever growing demand for food and the consequent deforestation process and loss of natural habitats in many understudied tropical regions. In this paper, we describe the outcome of a biodiversity research on tiger moths performed for the first time in a poorly studied Amazonian landscape—the savanna. We sampled tiger moths monthly with UV automatic light traps for 12 consecutive months in two sampling points in an area of savanna in eastern Amazon, and we compared our results to previously available data for eastern Amazon. We found a total of 91 species of which 80 were identified to species level. The most species-rich subtribes were Phaegopterina and Euchromiina with 32 species each. Species richness and abundance did not differ among sampling sites, but in general the species richness was higher during the dry season while abundance was higher during the wet season. This seasonal diversity pattern differs from the most common patterns recorded for savannas in other parts of the world. The species composition also changed in wet and dry seasons and correlated significantly with temperature and relative humidity. Our results suggest that the alpha diversity of the Amazonian savannas in our sampling area is lower than that in nearby rain forests and similar to that in agriculturally disturbed areas surrounded by rain forests. However, the species composition differed considerably from natural and disturbed areas. These results highlight the need of basic biodiversity surveys of insects in Amazonian savannas.     

Distance‐driven species turnover in Bornean rainforests: homogeneity and heterogeneity in primary and post‐logging forests

Selective logging is practiced extensively within tropical rainforests of south‐east Asia, and its impact on local biodiversity is well documented. Little is known, however, about the impact of selective logging on patterns of spatial heterogeneity of species. We set out to test the hypothesis that selective logging will lead to a homogenization of the associated faunal assemblages, using moths (Lepidoptera) as our subject taxa. Large‐scale transects were established within primary and post‐logging lowland mixed dipterocarp rainforests around the Danum Valley Conservation Area and surroundings, Sabah, Malaysia (4°50′N–5°00′N and 117°35′E–117°45′E). Five study sites were located within each habitat with geometrically increasing inter‐site distances. Macro‐moths plus Pyraloidea were sampled by light trapping in 2007 and 2008. Vegetation state was also measured at each site. A clear distance–decay relationship (decreasing assemblage similarity with increasing geographic distances) was observed in primary forest but was absent in the post‐logging forest. Large, comparable numbers of macro‐moth species were found in both primary and post‐logging forests. There were no significant differences in moth assemblage composition between primary and post‐logging forests. There are important structural differences between primary and post‐logging forests reflected in the moth assemblages. A two‐stage hypothesis combining both neutral and niche concepts is probably the most parsimonious explanation of these results. First, the composition of the moth assemblage is almost certainly determined locally by the variety of plant–hosts available to larvae, with the plants representing important niche dimensions for the moth species. Second the turnover (or lack of same) in the underlying plant assemblage probably reflects clumping and, in turn, dispersal capacity of the commoner plants in each forest type. Although the impact of selective logging may be subtle, this study suggests that selective logging results in the spatial homogenization of macro‐moth assemblages.     

Saproxylic moths reveal complex within-group and group-environment patterns

We investigated saproxylic moths of the family Tineidae, a neglected group inhabiting wood-decaying fungi and dead wood, within the Bia?owie?a Primeval Forest in Poland. Study data were obtained from the collection of 280 fruiting bodies of wood-decaying fungi and the subsequent rearing of adults. Spatial and statistical distribution of saproxylic moths, relationship among species and the influence of environment reflected by interaction with tree and fungal species together with tree and stand level characteristics were studied. Fifteen species and 533 individuals of saproxylic moths were reared. The fungal species, number of fruiting bodies and standing position of a tree influenced species richness. Moth abundance was influenced by fungal species, coniferous trees, increasing tree diameter, number of fruiting bodies and brown rot. Moth abundance was also enhanced by standing dead trees located in managed forests with higher canopy closure. Analyses indicate that several moth species favor a particular rot type and that some fungi host a richer fauna than others. Furthermore, our results indicate mutually independent fungal colonization events by saproxylic moth species, and thus a possible mechanism exists for competition avoidance with other saproxylic moths. Saproxylic moths revealed complex within-group patterns that responded differently to environmental variables. Thus, potential conservation of these organisms requires various approaches including ecosystem management, especially in the context of addressing their diverse habitat requirements.     

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.     

地形异质性对云南普洱季风常绿阔叶林物种多样性的影响

地形异质性通过调控树木生长所需的养分、水分和光照等而成为亚热带森林结构与物种组成的重要驱动因子。但是, 地形异质性对季风常绿阔叶林物种多样性及其分布影响的研究还相对较少。该文基于云南普洱30 hm²森林动态监测样地(大样地) 750个20 m × 20 m的样方调查数据, 以海拔、坡度、凹凸度和坡向4个地形因子为变量, 采用C均值模糊聚类分析大样地的地形类型, 进而分析不同地形条件下的群落物种组成及群落物种多样性; 采用Torus转换检验法, 探讨物种与地形关联性, 为季风常绿阔叶林生物多样性保护提供科学依据。研究结果表明, 大样地可分为山脊、陡坡、缓坡、高谷和沟谷等5类地形, 地形面积分别是8.00、6.04、7.68、2.76和5.52 hm²。大样地中胸径(DBH) ≥ 1 cm的木本植物个体153 418株, 分属79科179属271种。5类地形中, 物种丰富度、不同径级的植株密度和比例明显不同, 多样性及优势物种多度分布具有较大差异。种-面积曲线表明, 同等面积条件下, 随着取样面积增加, 山脊的物种丰富度始终最小, 高谷次之, 沟谷的物种丰富度始终最大。种-个体数累积曲线表明, 随着个体数增加, 山脊物种丰富度的累积速率最小, 种丰富度增加缓慢, 高谷次之。在被检验的123个物种中, 与地形相关的物种有83个, 高达67.5%的物种与至少一类地形存在显著相关关系。山脊和缓坡中与地形具有显著负相关关系的物种数超过显著正相关的物种数; 而与陡坡、高谷和沟谷显著正相关的物种数高于显著负相关的物种数。普洱大样地地形异质性对物种多样性维持的贡献率为7.8%。     

Tree species diversity of tropical forest vegetation in Xishuangbanna, SW China

Tree species diversity of four tropical forest vegetation types was investigated in Xishuangbanna, southwestern China. These are: tropical seasonal rain forest, tropical montane rain forest, evergreen broad-leaved forest and monsoon forest over limestone. A total of 17 samples were taken and four species diversity indices were calculated: Shannon-Wiener's H, the complement of Simpson's index, d, Fisher's and evenness index E. The results reveal the long-tailed rank/abundance diagrams of these forests. However, this feature is greatly reduced in the samples of monsoon forest over limestone. Tropical seasonal rain forest shows the highest tree species diversity of all four vegetation types. Owing to the variation of microenvironment, diversity values within the same vegetation type vary between the samples from different patches. The tree species diversity of single-dominant rain forest is not significantly lower than that of mixed rain forest, because the dominant species of some single-dominant rain forests are principally in the emergent layer. This is composed of sparse and huge trees of one species and, consequently, creates a unique canopy architecture and more heterogeneous microenvironments for the more diversified species composition under the emergent layer. The occurrence of tree species with small population sizes, particularly of species represented by only one individual, is highly correlated with the tree species diversity of the local forest vegetation. They are crucial elements in the richness of local biodiversity.     

Bird species richness in vegetation fences and in strips of residual rain forest vegetation at Los Tuxtlas, Mexico

Fragmentation of the lowland tropical rain forest has resulted in loss of animal and plant species and isolation of remaining populations that puts them at risk. At Los Tuxtlas, Mexico, lowland rain forests are particularly diverse in the avian fauna they contain and while most of the forests have been fragmented by human activity, many of the fragments still harbor diverse assemblages of bird species. In these landscapes, linear strips of residual rain forest vegetation along streams as well as linear strips of vegetation fences (live fences) crossing the pastures might provide some connectivity to bird populations existed in forest fragments. We investigated bird species richness and relative abundance in one 6-km long section of live fences (LF) bordering a dirt road and in two 6-km long sections of residual forest vegetation along a river (MR) and one permanent stream (BS). We used point count procedures which resulted in the count of 2984 birds representing 133 species. At the LF site we detected 74% of the species, 72% at the BS site and 57% at the MR site. Only 38% of the species were common among sites. Neotropical migratory birds accounted for 34–41% of the species counted at all sites. While edge and open habitat birds accounted for 6–10% of the species and for 50% of the records at the three vegetation strips, about 90% of the species were forest birds. Distance to forest fragments and degree of disturbance of the vegetation seemed to negatively influence bird species presence at the BS and MR strips. Rarefaction analysis indicated that the LF strip was richer in species than the other two sites, but the occurrence of the three vegetation strips in the landscape seem to favor the presence of many more species. We discuss the value of these vegetation strips to birds as stepping stones in the fragmented landscape.     

How the diversity,abundance, size and climbing mechanisms of woody lianas are related to biotic and abiotic factors in a subtropical secondary forest,Taiwan

Lianas are woody vines that play an important role in forest dynamics in tropical and subtropical areas. Their relationship to various biotic and abiotic conditions is, however, not yet wholly clear. We explored how the size, climbing mechanisms, diversity and abundance of woody lianas is related to host plant size, environmental factors and topography. Liana assemblages were examined in twenty 20 × 20 m plots in each of three topographic sites (valley, slope and ridge) in a subtropical secondary forest in southeastern Taiwan. The valley site had the highest abundance and species richness of lianas. The abiotic factors, soil pH and rock cover, were related to different topographic sites. Larger lianas were always found on larger host trees, while smaller lianas were found in smaller trees; no lianas with a DBH greater than 10 cm were found. Significantly more adhesive lianas were found on larger trees whereas twining and leaning-hook lianas were found in smaller trees. In conclusion, this study demonstrates that the species of liana is associated with the size and type of tree growing under different topographic conditions.     

Environmental correlates of avian diversity in lowland Panama rain forests

Aim The composition of communities is known to be influenced by biogeographical history, but also by local environmental conditions. Yet few studies have evaluated the relative importance of the direct and indirect effects of multiple factors on species diversity in rich Neotropical forests. Our study aims to assess drivers of change in local bird species richness in lowland tropical rain forests. Location Thirty‐two physiographic subregions along the corridor of the Panama Canal, Panama. Methods We mapped the distributions of all forest‐dwelling bird species and quantified the environmental characteristics of all subregions, including mean annual rainfall, topographic complexity, elevational variability, forest age and forest area. Plant species richness, believed to be correlated with structural complexity, was estimated by interpolation through kriging for subregions where data were unavailable. Results The study region has a strong rainfall gradient across a short distance (65 km), which is also accompanied by steep gradients in plant and bird species diversity. Path analysis showed that precipitation strongly affected plant species diversity, which in turn affected avian diversity. Forest age and topography affected bird diversity independently of plant diversity. Forest area and its proportion occurring in the largest two fragments of each subregion (habitat configuration) were also positive correlates of bird species richness. Main conclusions Our results suggest that plant species richness, known to be influenced in part by biogeographical history and geology, also affects bird species assemblages locally. We provide support for the hypothesis that bird species richness increases with structural complexity of the habitat. Our analysis of the distributions of the region's most disturbance‐sensitive bird species showed that subregions with more rainfall, more complex topography and older forests harboured not only richer communities but also more sensitive species; while subregions with the opposite characteristics usually lacked large fractions of the regional forest bird community and hosted only common, widely distributed species. Results also emphasize the importance of preserving forest diversity from habitat loss and fragmentation, and confirm that larger, continuous forest tracts are necessary to maintain the rich avian diversity in the region.