Host tree utilization by epiphytic orchids in different land-use intensities in Kathmandu Valley, Nepal

Adhikari, Yagya P.; Fischer, H; Fischer, Anton

doi:10.1007/s11258-012-0099-0

Cited by 49 publications

(24 citation statements)

References 34 publications

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“…The importance of genetic variation in physical bark characteristics as habitat for arthropod communities is demonstrated by Barbour et al (2009), where they show that a largely predaceous spider community responds positively to the exfoliating bark and crevices that differ greatly among geographic races of Eucalyptus globulus. The heterogeneous surface of rough bark may facilitate the establishment and growth of epiphytes, because it catches dispersing propagules, offers microsite shelter from desiccation, and may have increased moisture holding capacity (Lamit et al 2011a, Adhikari et al 2012. We recognize that in some habitats, smoothbarked trees can be rich in lichens, and suggest that the benefits of rough bark to lichens may be especially important in arid environments, such as our study sites.…”

Section: Lichen Response To Tree Genotypementioning

confidence: 93%

Genotype variation in bark texture drives lichen community assembly across multiple environments

Lamit

Lau

Næsborg

et al. 2015

Ecology

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A major goal of community genetics is to understand the influence of genetic variation within a species on ecological communities. Although well-documented for some organisms, additional research is necessary to understand the relative and interactive effects of genotype and environment on biodiversity, identify mechanisms through which tree genotype influences communities, and connect this emerging field with existing themes in ecology. We employ an underutilized but ecologically significant group of organisms, epiphytic bark lichens, to understand the relative importance of Populus angustifolia (narrowleaf cottonwood) genotype and environment on associated organisms within the context of community assembly and host ontogeny. Several key findings emerged. (1) In a single common garden, tree genotype explained 18-33% and 51% of the variation in lichen community variables and rough bark cover, respectively. (2) Across replicated common gardens, tree genotype affected lichen species richness, total lichen cover, lichen species composition, and rough bark cover, whereas environment only influenced composition and there were no genotype by environment interactions. (3) Rough bark cover was positively correlated with total lichen cover and richness, and was associated with a shift in species composition; these patterns occurred with variation in rough bark cover among tree genotypes of the same age in common gardens and with increasing rough bark cover along a -40 year tree age gradient in a natural riparian stand. (4) In a common garden, 20-year-old parent trees with smooth bark had poorly developed lichen communities, similar to their 10-year-old ramets (root suckers) growing in close proximity, while parent trees with high rough bark cover had more developed communities than their ramets. These findings indicate that epiphytic lichens are influenced by host genotype, an effect that is robust across divergent environments. Furthermore, the response to tree genotype is likely the result of genetic variation in the timing of the ontogenetic shift from smooth to rough bark allowing communities on some genotypes to assemble faster than those on other genotypes. Organisms outside the typical sphere of community genetics, such as lichens, can help address critical issues and connect plant genotype effects to long-established streams of biological research, such as ontogeny and community assembly.

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Section: Lichen Response To Tree Genotypementioning

confidence: 93%

Genotype variation in bark texture drives lichen community assembly across multiple environments

Lamit

Lau

Næsborg

et al. 2015

Ecology

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“…In addition, host preference in orchids may be governed by the distribution of their mycorrhizal symbionts that are needed for seed germination (Arditti 1992, Hietz & Hietz-Seifert 1995, Tupac-Otero et al 2004. Studies that address the distribution patterns of epiphytic orchids in montane forests examine their specificity toward some phorophytes and additionally their relationship to the structural characteristics of them (Migenis & Ackerman 1993, Tremblay et al 1998, Bergstrom & Carter 2008, Adhikari et al 2012.…”

mentioning

confidence: 99%

Host affinity and vertical distribution of epiphytic orchids in a montane cloud forest in southern Mexico

2018

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Background: The host´s structural characteristics provide diverse microhabitats that influence the distribution patterns of the epiphytes at different vertical zones and among tree species.Hypotheses: Epiphytic orchids have preference for larger host trees and with non-exfoliating rough bark, while the limiting hosts will be those of smaller size and smooth and exfoliating bark, and there will be fewer individuals in the upper canopy of the host trees because the micro-environmental conditions are more stressful compared to the middle and lower parts of the host trees.Methods: The host preferences and vertical distribution of the epiphytic orchids were analyzed in 20 montane cloud forest fragments. In each fragment, two transects of 2 × 50 m were drawn, and the trees with a diameter at a breast height ≥ 20 cm were recorded. In each tree, basal area was quantified and bark texture was characterized. In each tree and vertical zone, the orchid species present were identified and quantified.Results: Orchid distribution patterns vary between vertical zones and host tree species, and the richness is related to host size and bark texture. The highest species richness and number of epiphytic orchid’s individuals were recorded in host trees with fissured bark and larger size. The distribution of orchids in the host was not homogeneous nor was it related to any particular host species. However, five trees species were considered as host preferred, while five tree species were limiting hosts. The highest richness was recorded in vertical zone II and the lowest in zones I and V.Conclusions: Larger trees contain greater richness of epiphytic orchids, because they offer better conditions for their establishment, provide a great diversity of microhabitats, greater time and area for epiphytic colonization events. The texture of the bark is a relevant factor in the host preference, and in the hosts with smooth bark, the presence of epiphytic orchids depends on the accumulation of organic matter.

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“…This observation was consistent with results reported for lichens, which prefer maple trees with shallow, vertical‐line fissures to pine trees with pleated and flaky bark (McDonald et al., ). Line‐shaped fissures might improve stem flow of water and therefore modify chemical properties of bark such as pH, which influences seed germination and orchid distribution (Frei and Dodson, ; Adhikari et al., ). Our analysis also found a close association between microrelief characteristics and bark water storage; species preferred by orchids had higher water‐retention capacity, consistent with a previous study (Callaway et al., ).…”

Section: Discussionmentioning

confidence: 99%

Bark water storage capacity influences epiphytic orchid preference for host trees

Zarate‐García

Noguera-Savelli

Andrade‐Canto

et al. 2020

American J of Botany

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PREMISE: Of all orchid species described, 70% live on phorophytes. Trees offer a vital space with characteristics that influence the successful establishment and life cycle of orchids. Field inventory and distribution analysis suggest that phorophyte selection is biased to certain tree species that would serve as better hosts. Phorophyte bark is known as an important factor that influences this preference, but the chemical and physical properties of bark that contribute to creating a favorable space for orchids are still poorly understood. In this work, the effect of bark physical characteristics on phorophyte preference of tropical orchids was studied. METHODS:Orchids and their phorophytes were counted and identified along transects inside two natural reserves in Southeast Mexico. A rhytidome classification was used to describe the bark decoration patterns of the phorophytes. To quantify bark fissuring, we developed a new protocol based on image processing of light micrographs using free-access software. Bark topology characterization was complemented with scanning electronic microscopy. Maximum and minimum water content was also determined. RESULTS:Analyses of bark decorations and bark fissuring were not enough to explain the preference found for some tropical trees. In contrast, a positive relationship was found among water-storage capacity, bark porosity, and phorophyte preference. The host trees preferred by most orchids have bark with higher pore density and higher water retention after draining. CONCLUSIONS: Unexpectedly, the phorophytes preferred by orchids are not those with more fissured bark but those with a higher ability to retain minimum water content after draining, which is a bark property positively correlated with higher pore density. Our data indicate that the bark microenvironment, determined by topology and water storage capacity, has a pivotal role in phorophyte specificity, a key factor that affects orchid diversity and distribution in the world.

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Host tree utilization by epiphytic orchids in different land-use intensities in Kathmandu Valley, Nepal

Cited by 49 publications

References 34 publications

Genotype variation in bark texture drives lichen community assembly across multiple environments

Genotype variation in bark texture drives lichen community assembly across multiple environments

Host affinity and vertical distribution of epiphytic orchids in a montane cloud forest in southern Mexico

Bark water storage capacity influences epiphytic orchid preference for host trees

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