Fate of epiphytes on phorophytes with different architectural characteristics along the perturbation gradient of Sabal mexicana forests in Veracruz,Mexico

Question: Vascular epiphytes and hemiepiphytes (E/HE) in neotropical forests account for a large fraction of plant richness, but little is known of how the interplay between phorophyte architectural characteristics and habitat perturbation affect communities of E/HE. Location: Sabal mexicana forests in a coastal area of Veracruz, Mexico. Methods: We compared communities of E/HE on phorophytes with different architectural characteristics – the palm S. mexicana and non‐palm phorophytes – in three environments: conserved sites, perturbed sites and small regenerated forest fragments. We combined traditional (abundance, species richness, similarity and complementarity indices) and more recent (phylogenetic diversity) metrics to describe the communities of E/HE. Results: Overall, we recorded 924 E/HE individuals (nine families, 16 genera and 21 species). The abundance and species richness of E/HE was higher on palms than on non‐palm phorophytes. Abundance‐based complementarities between phorophytes and sites were high. We detected clear changes in community structure of E/HE with habitat perturbation, but there were no effects on the phylogenetic diversity of the E/HE community. Palm phorophytes hosted a more phylogenetically diverse community of E/HE than did non‐palm phorophytes. Conclusions: Palm phorophytes are key elements supporting the conservation of resilient communities of E/HE in S. mexicana forest. Habitat fragmentation has a strong effect on the structure of the E/HE community in S. mexicana forests. Ferns are the group of epiphytes most severely affected by habitat perturbation, but we detected no significant effect on the phylogenetic diversity of the community.     

Low modularity and specialization in a commensalistic epiphyte–phorophyte network in a tropical cloud forest

Species interactions can shape the structure of natural communities. Such sets of interactions have been described as complex ecological networks, an example of which is the commensal network formed by epiphyte–phorophyte interactions. Vascular epiphytes germinate and grow on phorophytes (support trees), assuming a horizontal distribution (among the phorophyte species) and a vertical distribution (from the base of the tree trunk to the crown of phorophytes, i.e., through ecological zones). Here, we investigated the organization of these structural dimensions of the epiphyte–phorophyte network in a Brazilian tropical montane cloud forest. The analyzed network, comprising 66 epiphyte species and 22 phorophyte species, exhibited a nested structure with a low degree of specialization, a typical pattern for epiphyte–phorophyte networks in forests. The network was slightly modular, with 65% of the species common to three modules, and had vertical structure corresponding to the vertical organization of the phorophytes. The size (diameter at breast height) of phorophyte individuals influenced the network structure, possibly due to the increase in habitat area, the time available for colonization by epiphytes, and a greater number of microenvironments. We found that the distribution of the epiphyte species differed between the phorophyte ecological zones, with greater richness in the lower portions and greater abundance in the upper portions of the phorophytes. The results provide relevant guidance for future research on the characteristics and the vertical and horizontal organization of vascular epiphyte and phorophyte networks. Abstract in Portuguese is available with online material.     

Species richness,composition, and spatial distribution of vascular epiphytes in Amazonian black-water floodplain forests

This study examines the occurrence of vascular epiphytic species in Central Amazonian black-water floodplain forests (igapó) and considers whether their horizontal and vertical distribution is influenced by the flood pulse, as is the case with tree species (phorophytes). Research was conducted in sixteen forest plots the Jaú National Park. In these, epiphytes on all phorophytes with DBH ≥ 10 cm were identified. We measured flood height using the watermark left by the last high-water period, then estimated the height relative to the ground of every epiphytic individual. We recorded 653 individuals in 37 species, distributed on 109 phorophytes. Igapó floodplain forests have much lower richness and abundance of vascular epiphyte species than do other Amazonian forests. This may reflect the limitation of available sites for colonization (only 24.9% of studied trees were occupied by epiphytes). Holoepiphytes predominated, and the combined presence of a flood-pulse, linked to the nutrient-poor soil poor seems to limit the occurrence of nomadic vines. Horizontal distribution of epiphytes followed the distribution of phorophytes, which in turn followed the flood-level gradient. Also flooding interacted strongly with vertical zonation to determine species richness. As already well-reported for trees, and unlike reports of epiphytes in other floodplains, flooding strongly influenced richness and distribution of vascular epiphytes in the studied igapó forests.     

Removal of Nonnative Vines and Post‐Hurricane Recruitment in Tropical Hardwood Forests of Florida1

In hardwood subtropical forests of southern Florida, nonnative vines have been hypothesized to be detrimental, as many species form dense “vine blankets” that shroud the forest. To investigate the effects of nonnative vines in post‐hurricane regeneration, we set up four large (two pairs of 30 X 60 m) study areas in each of three study sites. One of each pair was unmanaged and the other was managed by removal of nonnative plants, predominantly vines. Within these areas, we sampled vegetation in 5 X 5 m plots for stems 2 cm DBH (diameter at breast height) or greater and in 2 X 0.5 m plots for stems of all sizes. For five years, at annual censuses, we tagged and measured stems of vines, trees, shrubs and herbs in these plots. For each 5 X 5 m plot, we estimated percent coverage by individual vine species, using native and nonnative vines as classes. We investigated the hypotheses that: (1) plot coverage, occurrence and recruitment of nonnative vines were greater than that of native vines in unmanaged plots; (2) the management program was effective at reducing cover by nonnative vines; and (3) reduction of cover by nonnative vines improved recruitment of seedlings and saplings of native trees, shrubs, and herbs. In unmanaged plots, nonnative vines recruited more seedlings and had a significantly higher plot‐cover index, but not a higher frequency of occurrence. Management significantly reduced cover by nonnative vines and had a significant overall positive effect on recruitment of seedlings and saplings of native trees, shrubs and herbs. Management also affected the seedling community (which included vines, trees, shrubs, and herbs) in some unanticipated ways, favoring early successional species for a longer period of time. The vine species with the greatest potential to “strangle” gaps were those that rapidly formed dense cover, had shade tolerant seedling recruitment, and were animal‐dispersed. This suite of traits was more common in the nonnative vines than in the native vines. Our results suggest that some vines may alter the spatiotemporal pattern of recruitment sites in a forest ecosystem following a natural disturbance by creating many very shady spots very quickly.     

Floristic diversity of sabal palmetto woodland: an endemic and endangered vegetation type from Mexico

The sabal palmetto woodland is a tropical plant formation dominated by Sabal mexicana, with restricted distribution to southeast Mexico. Sabal palms grow on poor soils but accumulate large quantities of organic substrate in their crowns, harboring a contingent of plants that use it as phorophyte. Although it is a threatened formation, basic information on its biodiversity is scant. We examined the floristic diversity of recruited (diameter at breast height, DBH, ≥1 cm) and understory (DBH ≤ 1 cm) plants, and its variation with anthropogenic disturbance. We also examined the floristic diversity of plants that use the sabal palms as phorophytes, and assessed its variation with human impact. All plants present in transects within a conserved and an adjacent perturbed area were sampled. The list of observed taxa shows that this vegetation has a clear affinity with tropical dry and wet forests of Mexico, with a small representation of taxa from desert ecosystems. The floristic contingent included a total of 81 species in 2000 m². Richness, composition and diversity were affected by disturbance. Recruited and understory vegetation in the disturbed site were 5- and 1.6-times less diverse than in the conserved site, and species of mature, conserved vegetation were substituted by heliophytes in the disturbed site. In contrast, abundance of palms and diversity and identity of epiphytic/hemiepiphytic plants were not affected by disturbance. We show that even monodominated tropical ecosystems growing on poor soils have a high floristic diversity and that current anthropogenic impact threatens not only species and populations but also entire plant formations.     

Aggregated recruitment patterns under adult crowns in Photinia glabra,a bird‐dispersed tree species

To clarify recruitment patterns of Photinia glabra, which is an evergreen, broad‐leaved, bird‐dispersed tree species, we analyzed spatial distribution in P. glabra recruits at each growth stage and demography of current‐year seedlings with respect to distributions of adults in a warm‐temperate secondary forest, western Japan. Although individuals ≥ 5 cm diameter at breast height (DBH) that had nearly produced fruits showed a random distribution, seedlings (≥ 1 year old, < 10‐cm stem length [SL]), small saplings (10 ≤ SL < 30 cm) and large saplings (≥ 30‐cm SL, < 5‐cm DBH) were clumped and associated with reproductive adults at approximately 2–3‐m scales, nearly equal to their average crown radius. Based on monitoring the demography of current‐year seedlings, emerged seedling density profoundly decreased, and no seedlings survived at longer than an adult's crown scales, with distance‐dependent mortality as a result of disease and herbivory not greatly affecting the current‐year seedling mortality. Thus, aggregated seed dispersal under the crown of adult P. glabra would directly influence the distribution of recruits for P. glabra in this forest. Of the bird‐dispersed tree species in this forest, P. glabra produced the highest amount of fruits during large crop years, and their fruits ripened during the late seasonal period (early January), suggesting that birds might be strongly attracted to these species, in turn leading to seeds being deposited mostly under the tree crowns. We propose that dispersal limitation would occur, even in a bird‐dispersed tree species such as P. glabra, owing to plant–bird interactions in the forest.     

Demography of the long‐lived conifer Agathis ovata in maquis and rainforest,New Caledonia

Abstract. The endemic New Caledonian conifer Agathis ovata occurs as an emergent tree in fire‐prone shrublands (maquis), and fire‐sensitive rainforest. Growth, survivorship and recruitment over 5 yr were compared for populations from forest and maquis on ultramafic substrates in New Caledonia to investigate whether demographic behaviour varied in response to the strongly contrasting forest and shrubland environments. Growth of seedlings and of small (30–100 cm height) and large (100 cm height; 5 cm DBH) saplings was slow, but varied significantly among stages, site types and years. The greatest difference in growth rates was among stages, seedlings growing 0.34 cm.yr^?1, small saplings 1.06 cm.yr^?1 and large saplings 2.13 cm.yr^?1. Tree DBH increased by only 0.05 cm.yr^?1 and, based on these rates, individuals with DBH of 30 cm are estimated to be more than 700 yr old. Few trees (3.5%) produced cones in any year and seedling recruitment was low, but some recruitment was recorded each year in both maquis and forest. Rates of recruitment per parent were highest in forest (1.28.yr^?1, cf 0.78.yr^?1), but the higher density of trees in maquis meant that overall recruitment was greater there (92 ha^?1.yr^?1, cf 56 ha^?1.yr^?1). Seedling mortality ranged from 0.9 to 2.9% among years with no significant difference between maquis and forest. No sapling mortality was recorded, but annual tree mortality ranged from 0 to 1.4%. Evidence from a recently burned site indicated that while trees may survive fire, seedlings and saplings do not. Post‐fire seedling recruitment per ha from surviving trees was four times lower than in unburned sites, but growth rates were four times higher. Similar demographic attributes, including high survivorship, low growth rate and low rates of recruitment over a long reproductive life, characterize Agathis ovata populations in both maquis and rainforest in New Caledonia and are indicative of a broad tolerance of light environments that is unusual among tree species. These demographic attributes help to explain the long‐term persistence of the species in these strongly contrasting habitats.     

后河自然保护区珍稀植物群落谱系结构的时空变化

群落中所有物种对的亲缘关系程度构成群落的谱系结构。研究群落的谱系结构可以有效地揭示环境过滤、竞争排斥、中性过程三大生态过程对群落构建的相对重要性。本文以湖北后河自然保护区1hm。固定样地的珍稀植物群落为研究对象,分别研究了5m×5m、10m×10m、20m×20m、30m×30m、40m×40m、50m×50m6个空间尺度和在10m×10m、20m×20m、30m×30m、40m×40m、50m×50m5个空间尺度下5cm≤DBH〈10cm、10cm≤DBH〈15cm、15cm≤DBH〈20cm、DBH≥20cm4个径级对亚热带常绿落叶阔叶混交林群落谱系结构的影响。结果发现：随着空间尺度的增加,谱系结构逐渐趋向聚集。随着径级的增大,群落谱系聚集程度越来越小。但当DBHI〉20cm时,群落谱系聚集度较高。在25m。的尺度上群落谱系结构表现为随机,而在100m^2及更大的尺度上群落谱系结构都表现为聚集,说明在亚热带常绿阔叶落叶混交林的群落构建过程中,小尺度上中性过程可能起主导作用,而大尺度上生态位过程可能更重要。     

杉木风景游憩林冠径与胸径关系研究

为研究杉木风景游憩林标准林分密度（立木株数）,确定合理抚育间伐强度提供科学依据。本文在福建将乐国有林场通过设置杉木人工林39块标准地和2 906株每木检尺实测数据,建立了福建将乐杉木人工林树冠径与胸径以及冠径与胸径比值(cd/D)关系,并分析了冠径与胸径比值在风景游憩林树木空间、林分密度和间伐强度中的应用。研究表明:胸径在2~43 cm之间时,相关系数(R²)达0.919 5,呈显著线性相关,其中2~35 cm模型精度较高,35~43 cm误差较大。通过对不同大小的杉木(cd/D)比值进行分析,得出随着胸径增大比值是逐渐减小的,并且减小的趋势随着胸径的增大趋于平稳,最后趋于一个常数。     

Differential survival among life stages contributes to co‐dominance of Abies mariesii and Abies veitchii in a sub‐alpine old‐growth forest

Questions: Are there interspecific differences in mortality and recruitment rates across life stages between two shade‐tolerant dominant trees in a sub‐alpine old‐growth forest? Do such differences in demography contribute to the coexistence and co‐dominance of the two species? Location: Sub‐alpine, old‐growth forest on Mt. Ontake, central Honshu, Japan. Methods: From 1980 to 2005, we recorded DBH and status (alive or dead) of all Abies mariesii and A. veitchii individuals (DBH ≥ 5 cm) in a 0.44‐ha plot. Based on this 25 year census, we quantified mortality and recruitment rates of the two species in three life stages (small tree, 5 cm ≤ DBH < 10 cm; subcanopy tree, 10 cm ≤ DBH < 20 cm; canopy tree, DBH ≥ 20 cm). Results: Significant interspecific differences in mortality and recruitment rates were observed in both the small tree and sub‐canopy tree stages. In this forest, saplings (< 5 cm DBH) are mostly buried by snow‐pack during winter. As a consequence, saplings of A. mariesii, which is snow and shade tolerant, show higher rates of recruitment into the small tree stage than do those of A. veitchii. Above the snow‐pack, trees must tolerate dry, cold temperatures. A. veitchii, which can more readily endure such climate conditions, showed lower mortality rate at the subcanopy stage and a higher recruitment rate into the canopy tree stage. This differential mortality and recruitment among life‐stages determines relative dominance of the two species in the canopy. Conclusion: Differential growth conditions along a vertical gradient in this old forest determine survival of the two species prior to reaching the canopy, and consequently allow co‐dominance at the canopy stage.     

桉树人工林更新方式对林下植物功能群的影响

该研究综合运用野外调查和室内分析的方法,评估桉树人工林林下植物功能群的组成、分布及更新方式和相关环境因子之间的关系。结果表明:林分更新5 a后,除了非禾本科杂草功能群外,其他林下植物功能群的物种丰富度均呈现不同程度的增加,但与对照组(砍伐迹地)相比,其差异程度均不显著(P0.05);与对照组相比,藤本和蕨类功能群的相对多度也出现增加趋势,但禾本科草本功能群显著减少(P0.05);木本、藤本和蕨类功能群的相对盖度也呈现增加趋势,但禾本科草本功能群与对照组相比显著减少(P0.05);主成分分析(PCA)发现萌芽更新或植苗更新林的林下植物功能群组成和分布与对照组相比均发生了显著的变异,但不同更新方式(萌芽和植苗)下其林下植物功能群组成和分布差异不明显;通过冗余分析(RDA)确定了冠层透光系数、土壤孔隙度、坡向和土壤氮磷比是影响该林地林下植物功能群的主要因子,它们的叠加效应能解释大于75%的林下植物功能群的变异,最终模型通过排序得到冠层透光系数是影响该林地林下植物功能群的最主要因子。短期的研究发现萌芽和植苗这两种不同的更新方式对桉树林下植物功能群的影响有限,这可能与这两种更新方式形成的林冠结构和土壤理化性质差异性较小有关。     

Conservation of Vascular Epiphyte Diversity in Shade Cacao Plantations in the Chocó Region of Ecuador

To assess the contributions of rustic shade cacao plantations to vascular epiphyte conservation, we compared epiphyte species richness, abundance, composition, and vertical distributions on shade trees and in the understories of six plantations and adjacent natural forests. On three phorophytes and three 10 × 10 m understory plots in each of the agroforestry plantations and natural forests, 54 and 77 species were observed, respectively. Individual-based rarefaction curves revealed that epiphyte species richness was significantly higher on forest phorophytes than on cacao farm shade trees; detailed analyses showed that the differences were confined to the inner and outer crown zones of the phorophytes. No differences in epiphyte species richness were found in understories. Araceae, Piperaceae, and Pteridophyta were less species-rich in plantations than in forests, while there were no differences in Orchidaceae and Bromeliaceae. Regression analysis revealed that epiphyte species richness on trunks varied with canopy cover, while abundance was more closely related to soil pH, canopy cover, and phorophyte height. For crown epiphytes, phorophyte diameter at breast height (dbh) explained much of the variation in species richness and abundance. There were also pronounced downward shifts in the vertical distributions of epiphyte species in agroforests relative to natural forests. The results confirm that epiphyte diversity, composition, and vertical distributions are useful indicators of human disturbance and showed that while the studied plantations serve to preserve portions of epiphyte diversity in the landscape, their presence does not fully compensate for the loss of forests.     

宝天曼国家级自然保护区落叶阔叶林密度制约效应对树木存活的影响

密度制约对物种共存起着重要作用。随着密度制约效应研究的深入, 亲缘关系较近的物种间表现出的密度制约效应逐渐被人们认识。本研究基于2009和2014年对宝天曼1 ha落叶阔叶林样地的2次调查数据, 利用广义线性混合模型分析了重要值排名前11位的物种不同邻域尺度的密度制约效应对不同径级(小径级(1 cm ≤ DBH < 5 cm)、中径级(5 cm ≤ DBH < 10 cm)、大径级(DBH ≥ 10 cm))目标个体存活的影响。研究表明: (1) 5年间样地中DBH ≥ 1 cm的所有个体的年均死亡率和增员率分别为5.85%和0.27%; (2)有5个物种的个体存活率与同种邻体个体数及同种邻体胸高断面积显著负相关; (3)小径级个体的存活在5 m的邻域范围内受同种密度制约和谱系密度制约的影响都很显著; 中径级个体在3个尺度上受到的密度制约和谱系密度制约的影响都不大; 大径级个体在7.5 m、10 m邻域范围内受谱系密度制约影响显著。结果表明, 同种密度制约和谱系密度制约效应对宝天曼落叶阔叶林不同生长阶段的树木个体影响不同。     

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。     

Ecological observations onHeteropsis Spp. (Araceae) in Southern Venezuela

This article contributes a brief review of the ethnobotany and ontogeny ofHeteropsis spp. (Araceae), reports the distribution and density of Heteropsis spp. in a tropical lowland rainforest in southern Venezuela, and explores the environmental variables that correlate best with the observedHeteropsis densities.Heteropsis occurred on 26% of the 4091 trees (≥10 cm DBH) inventoried in 67 plots (of 0.1 hectare, each). Mean Heteropsis colonization densities differed significantly between 11 local forest types and ranged from 0% (in seasonally deeply flooded forest and in semideciduous hill forest) to 74% (in sporadically flooded forest near small streams). Across forest types,Heteropsis occurred on a significantly greater number of trees between 20 and 50 cm DBH than expected for an even distribution over all size classes. Of the 90 most common potential host species in the plots, the giant herb Phenakospermum guyannense (L. C. Rich.) Endl. was the only one consistently and significantly avoided by Heteropsis, and no host species was significantly preferred across all forest types. Heteropsis densities were positively correlated with the depth of the fine root mat and the diversity of big lianas. They were negatively correlated with the concentration of exchangeable potassium, flooding depth, and the density of small lianas. We conclude that Heteropsis shows clear habitat preferences that reflect site differences in soil fertility, flooding regime and forest structure and could not be explained by the distribution of preferred or avoided host tree sizes or species.     

Effects of selective logging on tree diversity,composition and plant functional type patterns in a Bornean rain forest

Abstract. The effects of selective logging on tree diversity, changes in tree species composition and plant functional types were studied with the use of seven permanent plots in virgin and in logged forest. All plots were located in a lowland dipterocarp rain forest in East Kalimantan on the island of Borneo. Just after logging and during the following 20 yr tree diversity measured as Fishers’α was not significantly affected in logged forest plots. Temporal shifts in tree species composition were analysed with Principal Component Analysis (PCA). Logged forest plots had much larger changes over time than virgin forest plots. In the smallest diameter class, some logged forest plots showed a distinct trajectory in PCA space compared to virgin forest plots, while in larger diameter classes movement of logged plots in PCA space was random. This suggests that there is no predetermined community to which logged forest plots tend to shift when recovering from logging. We found a significant negative correlation between diameter increments and the species‐specific wood densities of tree species. Species‐specific wood density and potential tree height were used to assign species to five PFTs. As expected, logging increased the fraction of softwood stems in small diameter classes. In the largest diameter classes (≥ 50 cm DBH) a strong decrease of softwood emergent stems was found in logged forest plots. After more than 20 yr no recruitment was found of softwood emergent stems in selectively logged forest.     

POST-FIRE COLONIZATION OF A MEDITERRANEAN FOREST STAND BY EPIPHYTIC LICHENS

The post-fire colonization of a Quercus ilex forest by epiphytic lichens has been studied in Catalonia (NE Spain), eleven years after a fire. Specific richness and lichen biomass have been studied separately on Quercus ilex , Erica arborea , Rosmarinus officinalis . and Cistus albidus , to reveal possible differences among phorophytes in facilitating lichen establishment. Shrubs play an important role in colonization by common species whereas the stools of Quercus ilex offer a suitable substratum for rarer species. Cistus albidus , with the highest lichen diversity and 98·2% of the total biomass of macrolichens, is the most suitable phorophyte for lichen establishment.     

Climber species composition, abundance and relationship with trees in a Nigerian secondary forest

Climbers play different roles in forest biology and ecology and are the first to be eliminated during forest clearing but little is known about the species composition, distribution and relationship with tree species of this group of plants of tropical forest. This study thus investigated the species composition, abundance and tree relationship of climbers along altitudinal gradient in four 0.06 ha plots in a secondary forest at Ile‐Ife, Nigeria. All trees ≥10 cm g.b.h were examined for the presence of climbers in the plots. There were 49 climber species consisting of 35 liana and fourteen vine species distributed over 41 genera and 28 families in the forest. Lianas contributed 34% and vines 13.7% of the plant species in the forest. Climber basal area, density, number of species, genera and families increased with altitude. Forty‐two per cent (42%) of the trees in the forest carried climbers. There was significant positive correlation (P ≤ 0.05) between girth sizes of host trees of 31–50 cm with the girths of climbers on them indicating that trees of these girth sizes are highly susceptible to climber infestation. Tree species host density and size are important factors in determining the presence of climbers on a tree.     

Do vine species in neotropical forests see the forest or the trees?

Questions: Is the occurrence of vine species in neotropical rain forests primarily determined by properties of the forest (environmental factors), by properties of the trees (tree species or tree size) or are vines randomly distributed? Location: Maya Biosphere Reserve, Guatemala. Methods: In five 1‐ha plots that span variation from unlogged forest to forest impacted by recurrent human disturbance we recorded the presence of all climbing vine species on every tree. The presence of all free standing vine species and 11 environmental variables were recorded in 100‐m² subplots. The relationship of host tree diameter and host tree identity on single tree vine species richness was investigated by GLM modelling. Partial redundancy analyses were used to partition the variation in vine species composition on two sources: environmental factors and tree species identity. Results: Single tree vine richness increased with increasing host tree DBH and differed significantly among host species. For climbing vines, the ratio of variation in subplot presence explained by tree species and by environmental variables was ca. 4:1 (in the most disturbed logged plots slightly lower), for free standing vines this ratio varied from 1:2 in the most disturbed logged plots to 9:1 in reserve plots, while a ratio of ca. 1:1 was found for all plots analysed together. Conclusion: Different tree species have different probabilities of being infested by vines. Vines see both the forest and the trees; the environment is more important in earlier developmental stages, properties of individual trees become more important from the time vines start to climb.     

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.