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Liana Communities (liana + community)
Selected AbstractsSoil phosphorus and disturbance influence liana communities in a subtropical montane forestJOURNAL OF VEGETATION SCIENCE, Issue 3 2010Agustina Malizia Abstract Questions: What are the effects of soil, topography, treefall gaps, tree species composition, and tree density on liana species composition and total liana abundance? Location: A 6-ha permanent plot in a subtropical montane forest in northwest Argentina. Methods: Multiple regressions were used to quantify associations of liana species composition and total liana abundance with edaphic, disturbance and tree community variables. Gradients in liana and tree species composition were quantified using principal components analysis (PCA). Results: Liana species composition was correlated most strongly with soil phosphorus concentration (R2=0.55). Total liana aanased with phosphorus and the density of recent treefall gaps (R2=0.60). Conclusions: In our study area, liana composition and abundance are most strongly correlated with features of the physical environment, rather than host tree characteristics. Our results support the hypothesis that recent increases in liana abundance in mature tropical forests may be related to increased rates of gap formation. [source] Landscape context and microenvironment influences on liana communities within treefall gapsJOURNAL OF VEGETATION SCIENCE, Issue 5 2008Agustina Malizia Abstract Questions: How do gap aspect, openness, age and gap density in the surroundings affect diversity and composition of lianas within treefall gaps? Are the variation patterns in liana communities within treefall gaps associated with their climbing mechanisms? Location: Subtropical montane forests in northwestern Argentina. Methods: We used ordination analyses (NMDS) and multiple regressions to describe liana communities (species and climbing groups, stems , 1 cm) in 35 gaps located in a 6-ha plot and to assess relationships with aspect, canopy and subcanopy openness, age and density of recent (three to eight years old) and old (> 8 years old) gaps. Results: Treefall gaps segregated in the ordination diagrams based on their liana species and climbing mechanisms composition: gaps surrounded by a higher density of recent gaps showed higher densities of lianas species using tendrils, spines/hooks and voluble stems. Liana density and richness (independent of stem density) were also positively associated with the density of recent gaps in the surroundings, and negatively associated to gap age. The number of liana species corrected per area was negatively associated to gap aspect and subcanopy openness, and absolute number of liana species was positively associated to gap canopy openness. Conclusions: This study integrates the analysis of different factors influencing liana communities within treefall gaps, and shows that spatial context of gap density (a variable largely neglected in previous studies) is particularly important on lianas composition and diversity, probably by increasing propagule input and the availability of small trellises for support. [source] Impact of landscape spatial pattern on liana communities in tropical rainforests at Los Tuxtlas, MexicoAPPLIED VEGETATION SCIENCE, Issue 3 2009Víctor Arroyo-Rodríguez Abstract Questions: What are the species composition and species and stem densities of liana communities in tropical landscapes of different deforestation levels? Which spatial attributes (forest cover, patch area, shape and isolation) have the strongest influence on liana communities in these landscapes? Location: Forty-five rainforest patches in Los Tuxtlas Biosphere Reserve, Mexico. Methods: In three landscapes with different deforestation levels (HDL=4%; IDL=11%; and LDL=24% of remaining forest cover) liana communities (DBH ,2.5 cm) were characterized in 15 randomly selected patches per landscape (10 50 m × 2 m transects per patch=0.1 ha), and evaluated the effects of patch area, shape and isolation on liana species and stem density (number of species and stems per 0.1 ha). Results: A total of 64 taxa and 24 families were sampled. Species composition differed highly among landscapes, with HDL being the most dissimilar landscape. The response of lianas to landscape spatial pattern differed significantly among landscapes. Proximity to villages had a strong positive effect on species and stem densities in LDL and IDL. There was a sharp decrease in liana stem density in HDL, with four patches (27%) found to be unoccupied by lianas. Conclusions: Fragmentation may have a positive effect on lianas, partly because of edge effects. This positive effect seems to be limited by the proportion of remaining forest cover in the landscape, as the liana communities had collapsed in the most deforested landscape. [source] Effects of Logging on the Diversity of Lianas in a Lowland Tropical Rain Forest in Hainan Island, South ChinaBIOTROPICA, Issue 5 2009Yi Ding ABSTRACT Lianas are an integral part of tropical forest ecosystems, which usually respond strongly to severe disturbances, such as logging. To compare the effect of different logging systems on the lianas diversity in tropical rain forest, we recorded all lianas and trees ,1 cm dbh in two 40-year-old forest sites after clear cutting (CC) and selective cutting (SC) as well as in an old-growth (OG) lowland tropical rain forest on Hainan Island in south China. Results showed that OG contained fewer liana stems and lower species richness (stems: 261, richness: 42 in 1 ha) than CC (606, 52) and SC (727, 50). However, OG had the highest Fisher's , diversity index (17.3) and species richness per stem (0.184). Species composition and dbh class distribution of lianas varied significantly with different logging systems. The mean liana dbh in OG (22.1 cm) were higher than those in CC (7.0 cm) and SC (10.4 cm). Stem twining was the most frequent climbing mechanism represented in the forest, as shown by the greatest species richness, abundance, basal area, and host tree number with this mechanism. The percent of host tree stems ,4 cm dbh hosting at least one liana individual in SC (39%) was higher than CC (23%) and OG (19.5%). Large host trees (dbh,60 cm) were more likely to be infested by lianas in SC and OG. Our study demonstrated that logging disturbance could significantly change the composition and structure of liana communities in the lowland tropical rain forest of south China. [source] Censusing and Measuring Lianas: A Quantitative Comparison of the Common Methods,BIOTROPICA, Issue 5 2006Stefan A. Schnitzer ABSTRACT Lianas contribute to many aspects of tropical forest diversity and dynamics, and interest in liana ecology has grown substantially in recent years. Methods to census lianas and estimate biomass, however, differ among studies, possibly hindering attempts to compare liana communities. At Nouragues Research Station (French Guiana), we tested the extent to which liana abundance, basal area, and estimated biomass differed depending on stem diameter measurement location, inclusion of ramets, inclusion of lianas rooted within versus passing through the plot, and plot shape. We found that the mean per plot abundance and basal area of lianas were significantly greater when lianas were measured low on the stem, when ramets were included, and when lianas were sampled in transects (2 × 50 m) than in square plots (10 × 10 m). Mean per plot liana abundance and basal area were 21 percent and 58 percent greater, when stems were measured at the largest spot on the stem compared to 130 cm from the ground, respectively. Including liana ramets increased average per plot liana abundance, basal area, and estimated biomass by 19, 17, and 16 percent, respectively. To facilitate cross-study comparisons, we developed conversion equations that equate liana abundance, diameter, and basal area based on the measurements taken at four different stem locations. We tested these equations at Lambir Hills National Park, Malaysia and found that they did not differ significantly between the two sites, suggesting that the equations may be broadly applicable. Finally, we present a new allometric equation relating diameter and biomass developed from 424 lianas from five independent data sets collected in four countries. RÉSUMÉ Les lianes contribuent de diverse manière à la diversité et à la dynamique des forêts tropicales, et l'intérêt pour l'écologie des lianes s'est beaucoup accru ces dernières années. Cependant, les méthodes pour recenser les lianes et estimer leur biomasse varient d'une étude à l'autre, et peuvent entraver les tentatives de comparaison des communautés de lianes. A la Station de Recherche des Nouragues (Guyane Française), nous avons évalué la variation de l'abondance, de la surface terrière et de la biomasse des lianes, en fonction de la position de mesure du diamètre sur le tronc, de l'inclusion des rameaux, de l'inclusion des lianes enracinées dans la parcelle plutôt que passant dans la parcelle, et de la forme de la parcelle. Nous avons trouvé que l'abondance et la surface terrière moyennes des lianes par parcelle étaient significativement plus importantes lorsque les lianes étaient mesurées en bas de la tige, lorsque les rameaux étaient inclus, et lorsque les lianes étaient échantillonnées dans des transects (2x50m) plutôt que dans des parcelles carrées (10x10m). L'inclusion des rameaux dans l'échantillonnage augmentait l'abondance moyenne des lianes par parcelle de 19 pour cent, leur surface terrière de 17 pour cent et leur biomasse de 16 pour cent. Afin de faciliter les comparaisons entre études, nous avons développé des équations de conversion qui relient l'abondance, le diamètre et la surface terrière des lianes à partir de mesures prises à quatre endroits sur la tige. Nous avons testé la validité de ces équations au Parc National de Lambir Hills (Malaisie): les équations ne variaient pas de manière significative entre les deux sites, suggérant qu'elles pourraient être largement applicables. Finalement, nous présentons une nouvelle équation allométrique reliant diamètre et biomasse des lianes, construite à partir de 424 lianes de cinq ensembles de données échantillonnées dans quatre pays. [source] | ||||||||||