Distribution Of Vascular Epiphytes Research Articles

Distribución de epífitas vasculares sobre cuatro especies arbóreas en un bosque xerofítico del Chaco Húmedo, Argentina

Fil: Alvarez Arnesi, Eugenio. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentina

The distribution of vascular epiphytes over gradients of light and humidity in north‐east Australian rainforest

AbstractMicroclimatic conditions have a strong influence on the distribution of vascular epiphytes, among which orchids often occur in sunnier and more drought‐prone situations than ferns. However, very few studies have looked at the distribution of ferns and orchids in Australian tropical rainforests. By using transmitted light measurements at the locations of individual epiphytes and vapour pressure deficit from the canopy and base of host trees, we were able to determine the patterns of light and humidity in the rainforest environment, and the responses of ferns and orchids to variation in the physical environments. We surveyed five sites, ranging from 800 to 1180 m in elevation in the lower montane rainforests of north‐east Australia. Data loggers recorded the vapour pressure deficit (VPD) at the forest floor and canopy of each site. Light was correlated with height within the host tree and VPD differed significantly over position in the host tree and elevation. There was a strong partitioning of taxonomic groups over the light and VPD gradients. Orchids occurred in environments that had higher mean light levels and mean daily maximum VPD (27% and 0.43 kPa, respectively) than ferns (21% and 0.28 kPa). There was also strong microclimatic partitioning of species within taxonomic groups, suggesting that microclimatic factors play an important role in the realized niche spaces of epiphytes within the tropical Australian rainforest. Thus, the tested ecological generalizations made on tropical rainforest epiphytes apply in Australia.

Distribution of vascular epiphytes along a tropical elevational gradient: disentangling abiotic and biotic determinants

Epiphytic vascular plants are common species in humid tropical forests. Epiphytes are influenced by abiotic and biotic variables, but little is known about the relative importance of direct and indirect effects on epiphyte distribution. We surveyed 70 transects (10 m × 50 m) along an elevation gradient (180 m–1521 m) and sampled all vascular epiphytes and trees in a typical tropical forest on Hainan Island, south China. The direct and indirect effects of abiotic factors (climatic and edaphic) and tree community characteristics on epiphytes species diversity were examined. The abundance and richness of vascular epiphytes generally showed a unimodal curve with elevation and reached maximum value at ca. 1300 m. The species composition in transects from high elevation (above 1200 m) showed a more similar assemblage. Climate explained the most variation in epiphytes species diversity followed by tree community characteristics and soil features. Overall, climate (relative humidity) and tree community characteristics (tree size represented by basal area) had the strongest direct effects on epiphyte diversity while soil variables (soil water content and available phosphorus) mainly had indirect effects. Our study suggests that air humidity is the most important abiotic while stand basal area is the most important biotic determinants of epiphyte diversity along the tropical elevational gradient.

Composition and Distribution of Vascular Epiphytes in Different Areas in Obafemi Awolowo, Nigeria

Composition and distribution of vascular epiphytes were studied in three different areas at Obafemi Awolowo University estate, Nigeria. Each plot, in the selected area, was used for identification of host and epiphytes. Trees were carefully examined. Presence, positions on the host plants and life-forms of all the epiphytes were recorded. Diameter at breast height of the hosts, bark characteristics and height were determined. The climatic data of the areas were measured to determine the relationship between them and epiphytes distributions. Result showed 41 epiphytes belonging to 14 genera and 11 families were identified. Open area had the highest number of epiphytes (22) followed by forest patches (14) then secondary forest (five). The epiphytes were not host specific except epiphytic ferns and Ficus vogelii. Diameter at breast height has effect on the epiphytes distribution and composition. The distribution of epiphytes and environmental factors were lowest in the secondary forest. Moraceae was the most dominant host family (44.8%) while Nephrolepis undulata and Nephrolepis biserrata were the most common species of epiphytes. Most epiphytes preferred sub-canopy level, few occurred in the canopy level but none at emergent level. Climatic factors, diameter at breast height and bark characteristics of the host plants are useful in determining compositions and distributions of these epiphytes.

Composition and Distribution of Vascular Epiphytes in Different Areas in Obafemi Awolowo, Nigeria

Composition and Distribution of Vascular Epiphytes in Different Areas in Obafemi Awolowo, Nigeria

Composition and distribution of vascular epiphytes in a tropical semideciduous forest, Ghana

AbstractThe composition and distribution of vascular epiphytes were studied in two 1‐ha plots in the KNUST Botanic garden, Ghana. One‐hectare plot each was randomly set up in secondary and cultivated forests for the identification and enumeration of trees and shrubs (≥10 cm dbh), and epiphytes. Each tree was carefully examined, noting the presence, positions and life‐forms of all epiphytes. Twenty‐nine epiphyte (29) species belonging to fourteen genera and eleven families were identified in the study. These were hosted by 48 tree species and occurred in three life‐forms: hemi‐epiphytes (45%), casual epiphytes (45%) and true epiphytes (10%). The vascular epiphyte species made up 25.7% of all the identified plant species (excluding herbs and climbers) encountered. Host species (P < 0.001), habitat (P = 0.001) and their interaction (P < 0.001) had strong effects on epiphyte composition in the forests. Moraceae was the most dominant family (44.8%), while Nephrolepis undulata J. Sm. and N. biserrata (Sw.) Scott. were the commonest species of epiphytes. In terms of vertical distribution, most epiphytes were located on the trunk, while a few occurred in the canopy.

Host trait preferences and distribution of vascular epiphytes in a warm-temperate forest

To illustrate the ecological factors and process leading to the observed diversity patterns of vascular epiphytes, we examined the effect and importance of host tree traits on epiphyte richness and spatial aggregation of epiphytes. The study was conducted in warm-temperate forest in Japan. The recorded host traits were diameter, height, species, habitat topography, and growth rate, and we analyzed the effects and importance of these traits on three species groups: total epiphytic species, epiphytic orchid species, and epiphytic pteridophyte species. Diameter and species of host trees had the greatest influence on epiphytes and their magnitudes were roughly similar in all species groups. Growth rate and topography were less important than host size and species. Growth rate had a negative effect on all three groups, and topography was important for pteridophytes. Epiphyte richness did not exhibit clear spatial aggregation. Our results suggest that size, stability, and quality of the host are equally important in determining epiphyte colonization.

Diversity and distribution of vascular epiphytes in an insular Brazilian coastal forest

The study was carried out in a 3,000 m2 area of coastal Atlantic rain forest at Ilha do Mel island (25 degrees 30"S 48 degrees 23'W), on 100 assorted trees separated into 2 meter-high strata starting from the ground. In each stratum all of the occurring epiphytic species were recorded. The sampled species were grouped into three categories: exclusive, preferential, and indifferent, according to their abundance in each strata, and selective, preferential and indifferent, according to abundance on the forophytes. Intermediate strata registered the highest diversity. Six species were considered exclusive to one or two strata, 15 were restricted to some strata and 5 presented a broad distribution. No epiphytic species showed uniform horizontal distribution on the area. The epiphyte richness in a host tree varied from zero to 30. Regarding to fidelity on host tree species, few selective or preferential, and mainly indifferent epiphyte species, were found. A total of 82 epiphyte species were sampled in the surveyed tree, and the Wittaker plot indicate a highly dominant assemblage.

Diversity and distribution of vascular epiphytes in the forest lower canopy in Kibale National Park, western Uganda

AbstractThis study determined the species composition of the vascular epiphytes and the influence of substrates on the composition of the epiphytic species in the lower canopy of large host tree species. A single‐rope technique was used to access the canopy. The lower canopy had 59 species distributed in fifteen families and 34 genera. The dominant families on the basis of species numbers were Orchidaceae (23), Aspleniaceae (ten) and Polypodiaceae (six). The collections included 21 ferns, 23 orchids, five Ficus spp. and ten species of herbaceous epiphytes. While the orchids and other herbaceous species decreased along a decreasing rainfall gradient, the epiphytic ferns did not. Most epiphytes utilized the light humus and heavy humus types of substrate. It is possible that the nutrients and moisture in the substrates contribute to the high diversity of epiphytes in the canopy crowns.

Patterns in the diversity and distribution of epiphytes and vines in a New Zealand forest

Abstract Plants that rely on other plants for support (i.e. epiphytes and vines) are common in many forest ecosystems. However, they are poorly understood relative to terrestrial plants, especially in the Southern Hemisphere. To help bridge this gap, we evaluated the diversity and distribution of vascular epiphytes and vines on seven common tree species in a conifer‐broadleaf forest on New Zealand's North Island. Ground‐based surveys of 274 host trees were used to test whether epiphyte and vine diversity increased with tree diameter, and whether diversity‐diameter relationships differed among host tree species. Occurrence patterns of individual epiphyte and vine species were also assessed. We first evaluated the accuracy of ground‐based inventories by comparing surveys of trees made from the ground to those made from a canopy walkway. On average, 1 in 10 species of epiphytes and vines were unseen from the ground. However, sampling accuracy did not differ among the three host tree species growing along the walkway, suggesting unbiased comparisons could be made between hosts. Results from ground‐based surveys showed that species diversity of epiphytes and vines increased with host tree diameter. However, epiphytes showed stronger diversity‐diameter relationships than vines. Epiphyte diversity increased markedly in four host species and less strongly in the remaining three host species. Conversely, vines showed weak diversity‐diameter relationships in all host species. Occurrence patterns of individual species helped to explain diversity‐diameter relationships. All common epiphyte species occurred more frequently on large trees, regardless of host species, but occurrence patterns in most vine species were unrelated to tree size. Rather, the vines often showed strong host ‘preferences’. Overall results illustrate a rich diversity of distributional patterns in New Zealand's epiphytes and vines, and suggest that a similarly diverse set of ecological and evolutionary processes are responsible for them.

Vascular epiphyte distribution patterns: explaining the mid‐elevation richness peak

Summary We examined in situ diversity and distribution of vascular epiphytes, as well as site environmental variables at six sites along a continuous elevational gradient (30–2600 m a.s.l.) of old‐growth forest in Costa Rica. A total of 555 species of vascular epiphytes from 130 genera of 53 families were identified to species or morphospecies. The ferns were the most diverse group, with 138 species, followed by orchids (112 species). Cloud forest at 1000 m was the richest site, representing the maximum of a pronounced mid‐elevation peak in epiphyte species richness. Spatial randomizations of recorded elevational ranges suggest that the overall elevational richness pattern of most epiphyte groups on this transect is substantially influenced by the mid‐domain effect (MDE, the mid‐elevation overlap of large‐ranged species). Among the environmental factors considered (rainfall, temperature and canopy light environment), only rainfall was significantly correlated with richness. Different patterns of richness for vascular epiphytes and for trees indicate that mechanisms differ between life forms. We collected 26% of the estimated epiphyte species of Costa Rica along a single mountain transect. This, together with the finding that different groups and life forms varied in the elevation at which species richness peaked, highlights the need to conserve the few remaining intact elevational gradients in Latin America.

Patterns in species richness and distribution of vascular epiphytes in Chiapas, Mexico

AbstractAim We aim to assess regional patterns in the distribution and species richness of vascular epiphytes with an emphasis on forests that differ in altitude and the amount of rainfall.Location Tropical America, in particularly the 75,000 km2 large state of Chiapas in southern Mexico at 14.5–18.0°N. Chiapas is diverse in habitats with forests from sea‐level to the tree‐line at c. 3800 m altitude and with annual amounts of rainfall ranging from 800 to over 5000 mm. It is also one of the botanical best‐explored regions in the tropics.Methods First we give an overview of epiphyte inventories to date. Such epiphyte surveys were mostly carried out on the basis of surface area or individual trees and we discuss their problematic comparison. Applying a different methodological approach, we then used 12,276 unique vascular epiphyte plant collections from Chiapas that are deposited in various botanical collections. The locality data were georeferenced and compiled in a relational data base that was analysed using a geographical information system. To compare the number of species between inventories that differed in the numbers of records, we estimated the total richness, SChao, at each.Results We recorded 1173 vascular epiphyte species in thirty‐nine families (twenty‐three angiosperms), comprising c. 14% of all confirmed plant species in the state. About half of all species were orchids (568). Ferns and bromeliads were the next species‐rich groups with 244 and 101 species, respectively. Most species were found in the Montane Rain Forest and in the Central Plateau. Trees of different forest formations, rainfall regimes, altitudes and physiographical regions supported a characteristic epiphyte flora.Main conclusions We were able to confirm the presumed presence of a belt of high diversity at mid‐elevations (500–2000 m) in neotropical mountains. In contrast to predictions, however, we observed a decrease in diversity when the annual amount of rainfall exceeded 2500 mm. The decrease is attributed to wind‐dispersed orchids, bromeliads and Pteridophyta that may find establishment problematical under frequent downpours. In the wet but seasonal forests in Chiapas, this decrease is not compensated by plants in the animal‐dispersed Araceae that are abundant elsewhere. We presume that in addition to the annual amount of rainfall, its distribution in time determines the composition of the epiphyte community.