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Gerhard Zotz - One of the best experts on this subject based on the ideXlab platform.
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branchfall as a demographic filter for Epiphyte communities lessons from forest floor based sampling
PLOS ONE, 2015Co-Authors: Juliano Sarmento Cabral, Gerhard Zotz, Gunnar Petter, Glenda Mendietaleiva, Katrin Wagner, Holger KreftAbstract:Local variation in the abundance and richness of vascular Epiphytes is often attributed to environmental characteristics such as substrate and microclimate. Less is known, however, about the impacts of tree and branch turnover on Epiphyte communities. To address this issue, we surveyed branches and Epiphytes found on the forest floor in 96 transects in two forests (Atlantic rainforest in Brazil and Caribbean rainforest in Panama). In the Brazilian forest, we additionally distinguished between edge and core study sites. We quantified branch abundance, Epiphyte abundance, richness and proportion of adults to investigate the trends of these variables over branch diameter. Branches 90% of all branches on the forest floor. Abundance and richness of fallen Epiphytes per transect were highest in the Brazilian core transects and lowest in the Panamanian transects. The majority of Epiphytes on the floor (c. 65%) were found attached to branches. At all three study sites, branch abundance and branch diameter were negatively correlated, whereas Epiphyte abundance and richness per branch, as well as the proportion of adults were positively correlated with branch diameter. The relationship between branch diameter and absolute Epiphyte abundance or richness differed between study sites, which might be explained by differences in forest structure and dynamics. In the Panamanian forest, Epiphytes had been previously inventoried, allowing an evaluation of our surveying method by comparing canopy and forest floor samplings. Individuals found on the forest floor corresponded to 13% of all individuals on branches <10 cm in diameter (including crowns), with abundance, richness and composition trends on forest floor reflecting canopy trends. We argue that forest floor surveys provide useful floristic and, most notably, demographic information particularly on Epiphytes occurring on the thinnest branches, which are least accessible. Here, branchfall acts as an important demographic filter structuring Epiphyte communities.
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a hierarchical framework for investigating Epiphyte assemblages networks meta communities and scale
Ecology, 2010Co-Authors: K C Burns, Gerhard ZotzAbstract:Epiphytes are an important component of many forested ecosystems, yet our understanding of Epiphyte communities lags far behind that of terrestrial-based plant communities. This discrepancy is exacerbated by the lack of a theoretical context to assess patterns in Epiphyte community structure. We attempt to fill this gap by developing an analytical framework to investigate Epiphyte assemblages, which we then apply to a data set on Epiphyte distributions in a Panamanian rain forest. On a coarse scale, interactions between Epiphyte species and host tree species can be viewed as bipartite networks, similar to pollination and seed dispersal networks. On a finer scale, Epiphyte communities on individual host trees can be viewed as meta-communities, or suites of local Epiphyte communities connected by dispersal. Similar analytical tools are typically employed to investigate species interaction networks and meta-communities, thus providing a unified analytical framework to investigate coarse-scale (network) and fine-scale (meta-community) patterns in Epiphyte distributions. Coarse-scale analysis of the Panamanian data set showed that most Epiphyte species interacted with fewer host species than expected by chance. Fine-scale analyses showed that Epiphyte species richness on individual trees was lower than null model expectations. Therefore, Epiphyte distributions were clumped at both scales, perhaps as a result of dispersal limitations. Scale-dependent patterns in Epiphyte species composition were observed. Epiphyte-host networks showed evidence of negative co-occurrence patterns, which could arise from adaptations among Epiphyte species to avoid competition for host species, while most Epiphyte meta-communities were distributed at random. Application of our "meta-network" analytical framework in other locales may help to identify general patterns in the structure of Epiphyte assemblages and their variation in space and time.
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johansson revisited the spatial structure of Epiphyte assemblages
Journal of Vegetation Science, 2007Co-Authors: Gerhard ZotzAbstract:Abstract Question: Vertical zonation schemes are widely used in biodiversity studies with vascular Epiphytes as a tool to capture spatial distribution patterns, the one most commonly used was proposed by Johansson more than 30 years ago. Does a survey of the Epiphytes found on larger trees really yield a representative sample of the local community? Location: Lowland rainforest of the San Lorenzo Crane Plot, Republic of Panama. Methods: A complete census of the vascular Epiphytes on all trees > 1 cm DBH in 0.4 ha of undisturbed lowland forest was analysed with both cluster and discriminant analysis to detect groupings of Epiphyte species. Results: Six different groups of species were detected, five of them preferring different substrates on larger trees (as defined by (1) the height above ground at the attachment site, (2) the diameter of the substrate and (3) the occurrence on stem vs branches/twigs) and resembling to some extent the original Johansson zones. A sixth group of Epiphytes, comprising ca. 10...
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vascular Epiphytes in the temperate zones a review
Plant Ecology, 2005Co-Authors: Gerhard ZotzAbstract:Vascular Epiphytes are typically associated with tropical rainforests, whereas their occurrence in temperate forests is little appreciated. This review summarises the available information on epiphytism in the temperate zones ( g 23.5 degrees latitude), which has not been reviewed comprehensively for more than a century, and critically analyses the proposed mechanisms behind the observed biogeographical patterns. Although in the temperate zone epiphytic vascular plants are rarely as impressive as in tropical forests, there are noteworthy exceptions. Temperate rain forests of Chile and New Zealand, or montane forests in the Himalayas are comparable to many tropical forests in terms of Epiphyte biomass and diversity, but differ in their taxonomic spectrum: temperate Epiphyte communities are generally dominated by ferns and fern-allies. Other,temperate areas are not, however, necessarily barren of Epiphytes, as repeatedly implied. Quite in contrast, local populations of Epiphytes in a large number of other non-tropical areas in both the southern and the northern hemisphere can be quite conspicuous. The proposed reasons for the latitudinal gradients in Epiphyte abundance and,diversity (water scarcity or low temperatures) are not fully convincing and, moreover, still await experimental verification. Other factors, both historical (e.g., Pleistocene extinctions) and ecological (e.g., prevalence of conifers in the northern hemisphere), should also be taken into consideration to obtain a comprehensive explanation of the extant global distribution of vascular Epiphytes.
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the Epiphyte vegetation of the palm socratea exorrhiza correlations with tree size tree age and bryophyte cover
Journal of Tropical Ecology, 2003Co-Authors: Gerhard Zotz, Birgit VollrathAbstract:We conducted a survey of the Epiphyte flora growing on the stilt palm Socratea exorrhiza in a primary lowland rain forest in Panama by means of a canopy crane. For each palm in a 0.9-ha plot, we determined diameter at breast height, tree height, per cent bryophyte cover and the number, identity and attachment site of all vascular Epiphytes. The 118 palm trees hosted a total of 701 Epiphytes and hemi-Epiphytes, belonging to 66 species. Trees were estimated to be c. 20 y old before colonization with vascular Epiphytes began. Epiphyte species were highly clumped and segregated along the vertical axis of the trunk. Sequential colonization led to an increased number of species and individuals as the tree grows. Epiphytes were associated with bryophyte patches much more than expected by chance, but no species seemed to depend upon them for establishment. The influence of tree size, age and bryophyte cover on the composition of the Epiphyte community are discussed.
Alejandro Florespalacios - One of the best experts on this subject based on the ideXlab platform.
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dispersal limitation of tillandsia species correlates with rain and host structure in a central mexican tropical dry forest
PLOS ONE, 2017Co-Authors: Elizabeth Victorianoromero, Susana Valenciadiaz, Victor Hugo Toledohernandez, Alejandro FlorespalaciosAbstract:Seed dispersal permits the colonization of favorable habitats and generation of new populations, facilitating escape from habitats that are in decline. There is little experimental evidence of the factors that limit Epiphyte dispersion towards their hosts. In a tropical dry forest in central Mexico, we monitored the phenology of dispersion of Epiphyte species of the genus Tillandsia; we tested experimentally whether precipitation could cause failures in seed dispersal and whether seed capture differs among vertical strata and between host species with high (Bursera copallifera) and low (Conzattia multiflora) Epiphyte loads. With the exception of one species that presents late dispersion and low abundance, all of the species disperse prior to the onset of the rainy season. However, early rains immobilize the seeds, affecting up to 24% of the fruits in species with late dispersion. We observed that Tillandsia seeds reach both Bursera and Conzattia hosts, but found that adherence to the host is 4-5 times higher in Bursera. Furthermore, seeds liberated from Bursera travel shorter distances and up to half may remain within the same crown, while the highest seed capture takes place in the upper strata of the trees. We conclude that dispersion of Tillandsia seeds is limited by early rains and by the capture of seeds within the trees where populations concentrate. This pattern of capture also helps to explain the high concentrations of Epiphytes in certain hosts, while trees with few Epiphytes can be simultaneously considered deficient receivers and efficient exporters of seeds.
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does structural parasitism by Epiphytes exist a case study between tillandsia recurvata and parkinsonia praecox
Plant Biology, 2016Co-Authors: Alejandro FlorespalaciosAbstract:The effects that Epiphytes have on their hosts have been poorly explored in an experimentally. Correlational evidence suggests that Epiphytes may be either mutualists or structural parasites, as has been proposed for Tillandsia recurvata on Parkinsonia praecox. To test the effect of T. recurvata upon P. praecox, the Epiphyte load on branches of P. praecox was measured and two 1-year experiments were performed to detect the effect of transplantation/removal of Epiphytes and shade (0%, 35%. 50% and 80%) on shoot dynamics. If T. recurvata represents a selective pressure for P. praecox, then the frequency of branches carrying large Epiphyte loads will be high, and host shoot survival will decrease in the presence of T. recurvata and with increased shade. A weak inverse relationship between Epiphyte load and percentage of dead shoots in the host was detected. Shoot survival was independent of Epiphyte presence. Shade decreased shoot survival by 35-72%. Results suggest that at the study site, T. recurvata is a commensalist of P. praecox. An alternative hypothesis to explain the correlation between high Epiphyte load and branch/tree decay is that older branches carry more Epiphytes, receive more shade from neighbouring branches and could be undergoing a natural decline process.
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host preference and host limitation of vascular Epiphytes in a tropical dry forest of central mexico
Journal of Tropical Ecology, 2010Co-Authors: Carmen Agglael Vergaratorres, Mary Carmen Pachecoalvarez, Alejandro FlorespalaciosAbstract:It has been suggested that vascular Epiphyte composition and abundance may be influenced by forest host composition. We studied the Epiphyte species distribution among host species of a tropical dry forest in Mexico. All the Epiphyte stands supported by woody plants (dbh > 3 cm) of ten forest plots (0.1 ha each) were counted. We measured the dbh of all the hosts, noted their bark characteristics (texture and peeling behaviour), and measured the bark thickness of the most abundant host species. Epiphyte distribution was biased toward a high concentration of Epiphytes in three host species and a lower abundance of Epiphytes on five host species. This was consistent among Epiphyte taxa and host species, allowing us to classify hosts as preferred (with more Epiphyte stands than expected by chance) and limiting species (with fewer Epiphyte stands than expected by chance), at a community level. Host quality did not relate to mean phorophyte size (measured as basal area) or to bark characteristics (peeling behaviour, thickness and texture) between species. For some Epiphyte taxa, the observed distribution indicated that the forest contained preferred and limiting host species mainly. Our data suggest that the Epiphyte species in the forest studied could be host limited. We concluded that neither host size nor obvious bark characteristics can be used to predict Epiphyte distribution and that further research is necessary.
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effect of host bark extracts on seed germination in tillandsia recurvata an epiphytic bromeliad
Journal of Tropical Ecology, 2010Co-Authors: Susana Valenciadiaz, Alejandro Florespalacios, Veronica Rodriguezlopez, Elsa Venturazapata, Antonio JimenezaparicioAbstract:Tree species are potential hosts for Epiphytes; however in some forests Epiphytes have a biased distribution among hosts. In a tropical dry forest of Mexico, previous research showed that there are trees with few Epiphytes. It is possible that the bark of these hosts contain allelochemicals that influence Epiphyte seed germination. The aims of this study were (1) to determine whether hosts with low Epiphyte abundance (Ipomoea murucoides, I. pauciflora and Lysiloma acapulcense) would inhibit seed germination of Tillandsia recurvata through aqueous and organic bark extracts, (2) to determine whether germination of T. recurvata would differ among the hosts with low Epiphyte abundance and a host with high Epiphyte abundance (Bursera copallifera) and (3) to relate the chemical composition of organic bark extracts with inhibition of T. recurvata seed germination. Hexanic and dichloromethanic extracts were partially chemically characterized. Total phenolics and flavonoids concentrations of methanolic extracts were analysed. Aqueous and organic bark extracts from hosts with few Epiphytes inhibited T. recurvata seed germination. Aqueous and dichloromethanic extracts of B. copallifera inhibited slightly the germination of T. recurvata. There was a positive correlation between concentration of flavonoids and inhibition of seed germination. Results suggest that a combination of compounds may be responsible for affecting the germination of T. recurvata. This study demonstrates the chemical effect of aqueous and organic bark extracts from hosts on germination of an epiphytic bromeliad.
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the relationship between tree size and Epiphyte species richness testing four different hypotheses
Journal of Biogeography, 2006Co-Authors: Alejandro Florespalacios, Jose G GarciafrancoAbstract:Aim For epiphytic plants trees are habitat units, and tree size determines Epiphyte species richness. While growing, trees generate vertical microhabitats that are exploited by Epiphytes. One would expect to find four different types of relationship between tree size and Epiphyte species richness: positive linear (young trees), neutral (old trees), negative (old decaying trees) and positive asymptotic (trees of mixed size class in a mature forest). We tested these relationships in plots of colonizing sweetgum trees in pastureland, isolated remnant trees in pastureland (old oaks) and sweetgum and oaks in a pristine forest. Location The study was carried out in a landscape shaped by the fragmentation of lower montane cloud forest in San Andres Tlalnelhuayocan (19°30′56′′ N and 96°59′50′′ W; 1500–1600 m a.s.l.) in central Veracruz, Mexico. Methods We measured the d.b.h. of all oaks and sweetgum trees (d.b.h. ≥ 5 cm) present in pastureland and in three 100 m2 plots of a lower montane cloud forest. All trees were climbed and species richness of the Epiphytes recorded. Results As expected, colonizer trees in pastureland showed a linear positive relationship. Although we found evidence that remnant oaks in pastureland had a neutral relationship between tree size and Epiphyte species richness, the low power of the test did not allow us to make conclusions about the kind of relationship. Mixed size-class pristine forest trees showed a positive linear relationship between tree size and Epiphyte species richness instead of a positive asymptotic one. Main conclusions Our results suggest that in the study area Epiphyte communities are unsaturated, as the number of species increases with tree size and does not reach a ceiling. This evidence supports the idea that the species–area relationship is not asymptotic. However, the Epiphyte community on remnant pastureland oaks may be saturated as Epiphyte species richness did not increase with tree size, but a larger sample size is needed to confirm the neutral pattern. Neutral, asymptotic and negative patterns in the relationship between tree size and Epiphyte species richness depend on the saturation of the trees by Epiphytes. Other studies have suggested tree saturation, but further research is necessary in order to confirm or rule out these patterns.
Wilhelm Barthlott - One of the best experts on this subject based on the ideXlab platform.
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effect of host tree traits on Epiphyte diversity in natural and anthropogenic habitats in ecuador
Biotropica, 2011Co-Authors: Nils Koster, Jurgen Nieder, Wilhelm BarthlottAbstract:Vascular Epiphytes represent a highly diverse element of tropical rain forests, but they depend strongly on the structure and taxonomic composition of their tree communities. For conservation planning, it is therefore critical to understand the effect of host tree characteristics on Epiphyte species richness in natural and anthropogenically transformed vegetation. Our study compares the effect of human land-use on Epiphyte diversity based on 220 study plots in a lowland rain forest and an Andean cloud forest in western Ecuador. We evaluate the relevance of host tree size and taxonomic identity for Epiphyte species richness in contiguous primary forests, forest fragments, isolated remnant trees (IRTs), and secondary forests. At both study sites, Epiphyte diversity was highest in primary forests, and it was lowest on IRTs and in secondary forests. Epiphyte species numbers of forest fragments were significantly reduced compared with the contiguous primary forest at the lowland study site, but not in the cloud forest area. Host tree size was a core predictor among secondary forests, but it had less significance within other habitat types. Taxonomic identity of the host trees also explained up to 61 percent of the variation in Epiphyte diversity, especially for IRTs. The structural and taxonomic composition of the tree community in anthropogenically transformed habitat types proved to be fundamental to Epiphyte diversity. This highlights the importance of deliberate selection of tree species for reforestation in conservation programs and the possible negative effects of selective logging in primary forests. Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp.
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conservation of Epiphyte diversity in an andean landscape transformed by human land use
Conservation Biology, 2009Co-Authors: Nils Koster, Jurgen Nieder, Karoline Friedrich, Wilhelm BarthlottAbstract:Epiphytes are diverse and important elements of tropical forests, but as canopy-dwelling organisms, they are highly vulnerable to deforestation. To assess the effect of deforestation on Epiphyte diversity and the potential for Epiphyte conservation in anthropogenically transformed habitats, we surveyed the epiphytic vegetation of an Ecuadorian cloud forest reserve and its surroundings. Our study was located on the western slopes of the Andes, a global center of biodiversity. We sampled vascular Epiphytes of 110 study plots in a continuous primary forest; 14 primary forest fragments; isolated remnant trees in young, middle-aged, and old pastures; and young and old secondary forests. It is the first study to include all relevant types of habitat transformation at a single study site and to compare Epiphyte diversity at different temporal stages of fragmentation. Epiphyte diversity was highest in continuous primary forest, followed by forest fragments and isolated remnant trees, and lowest in young secondary forests. Spatial parameters of habitat transformation, such as fragment area, distance to the continuous primary forest, or distance to the forest edge from inside the forest, had no significant effect on Epiphyte diversity. Hence, the influence of dispersal limitations appeared to be negligible or appeared to operate only over very short distances, whereas microclimatic edge effects acted only in the case of completely isolated trees, but not in larger forest fragments. Epiphyte diversity increased considerably with age of secondary forests, but species assemblages on isolated remnant trees were impoverished distinctly with time since isolation. Thus, isolated trees may serve for recolonization of secondary forests, but only for a relatively short time. We therefore suggest that the conservation of even small patches of primary forest within agricultural landscape matrices is essential for the long-term maintenance of the high Epiphyte diversity in tropical cloud forests.
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large scale diversity patterns of vascular Epiphytes in neotropical montane rain forests
Journal of Biogeography, 2004Co-Authors: Wolfgang Kuper, Holger Kreft, Jurgen Nieder, Nils Koster, Wilhelm BarthlottAbstract:Aim Epiphytes contribute up to 30% to the number of vascular plant species in certain global biodiversity hotspots, e.g. the Ecuadorian Andes. However, their large scale diversity patterns are still discussed on the base of results from a few, local Epiphyte inventories. Consequently, explanatory models on Epiphyte diversity concentrate on the impact of local climate on small scale Epiphyte species richness. Our aim was to analyse large scale elevational patterns of Epiphyte diversity integrating data from different geographic scales. Location Tropical America, with special emphasis on the Ecuadorian Andes. Methods Our study is based on two data sources. First, we analysed the elevational patterns of Epiphyte diversity based on the Catalogue of the Vascular Plants of Ecuador and the Libro Rojo de las Plantas Endemicas del Ecuador. Secondly, the floristic turnover between the Epiphyte inventories of seven montane and four lowland study sites in the Neotropics was analysed. Results The floristic turnover between Neotropical montane Epiphyte floras is higher than the one between lowland Epiphyte floras. Montane study sites located only a few kilometres apart from each other show considerable differences in their Epiphyte species inventories. Irrespectively of their similar dispersal mode, the floristic turnover is much higher for orchids than for Pteridophyta. The Orchidaceae are the species richest group in all of the examined 11 Neotropical Epiphyte floras. At the larger scale of the Ecuadorian Flora, c. 50% of the species in the elevational zone with maximum Epiphyte diversity (between 1000 and 1500 m) are orchids. Elevational patterns of Epiphyte diversity strongly reflect patterns of Orchidaceae. Main conclusions Our results support the observation of a 'mid-elevation bulge' of Epiphyte diversity by Gentry and Dodson. It has been frequently shown that the high humidity in mid-elevations is suitable to maintan a high Epiphyte species richness. Our findings show that in addition, large scale Epiphyte diversity in montane rain forest is increased by the high floristic turnover at local and regional scale. Based on the importance of Orchidaceae for Epiphyte diversity, we discuss that speciation processes corresponding to the highly diverse environment are a driving force for endemism, floristic heterogeneity and consequently for large scale Epiphyte species richness in montane forests.
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diversity and abundance of vascular Epiphytes a comparison of secondary vegetation and primary montane rain forest in the venezuelan andes
Plant Ecology, 2001Co-Authors: Wilhelm Barthlott, Viviane Schmitneuerburg, Jurgen Nieder, Stefan EngwaldAbstract:Species diversity of vascular Epiphyte plant communities was studied in La Carbonera, a montane rain forest dominated by Podocarpaceae in the Venezuelan Andes. We compared the Epiphyte communities of the primary, disturbed, and secondary forest areas of La Carbonera in order to augment the scarce knowledge on the effects of anthropogenic disturbance on these important elements of tropical vegetation. Diversity of vascular Epiphytes (191 species in the whole forest area) was low in the disturbed and secondary areas (81 spp.) compared to adjacent primary forest (178 spp.). Four types of disturbed forest and secondary vegetation supported different numbers of Epiphyte species, showing a decline with increasing degrees of disturbance (65 spp. along a road transect, 42 spp. on relict trees in disturbed forest, 13 spp. in a tree plantation and 7 spp. in a former clearing, both secondary vegetation units). Epiphytic species composition in primary and disturbed or secondary forest areas differed markedly: disturbed habitats harboured fewer fern and orchid species but more bromeliad species than the primary forest. Probably the families occurring only in primary forest sites of our study may be useful as bioindicators to determine the degree of disturbance in other habitats of mountain rain forests as well. Epiphyte abundance was also lower in disturbed habitats: a remnant emergent tree supported only about half as many Epiphyte individuals as a member of the same species of similar size in the primary forest. The decrease in species numbers and abundance as well as the differences in species composition are mainly due to the less diverse phorophyte structure and less differentiated microclimate in the disturbed and secondary vegetation compared to the primary forest.
Nils Koster - One of the best experts on this subject based on the ideXlab platform.
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effect of host tree traits on Epiphyte diversity in natural and anthropogenic habitats in ecuador
Biotropica, 2011Co-Authors: Nils Koster, Jurgen Nieder, Wilhelm BarthlottAbstract:Vascular Epiphytes represent a highly diverse element of tropical rain forests, but they depend strongly on the structure and taxonomic composition of their tree communities. For conservation planning, it is therefore critical to understand the effect of host tree characteristics on Epiphyte species richness in natural and anthropogenically transformed vegetation. Our study compares the effect of human land-use on Epiphyte diversity based on 220 study plots in a lowland rain forest and an Andean cloud forest in western Ecuador. We evaluate the relevance of host tree size and taxonomic identity for Epiphyte species richness in contiguous primary forests, forest fragments, isolated remnant trees (IRTs), and secondary forests. At both study sites, Epiphyte diversity was highest in primary forests, and it was lowest on IRTs and in secondary forests. Epiphyte species numbers of forest fragments were significantly reduced compared with the contiguous primary forest at the lowland study site, but not in the cloud forest area. Host tree size was a core predictor among secondary forests, but it had less significance within other habitat types. Taxonomic identity of the host trees also explained up to 61 percent of the variation in Epiphyte diversity, especially for IRTs. The structural and taxonomic composition of the tree community in anthropogenically transformed habitat types proved to be fundamental to Epiphyte diversity. This highlights the importance of deliberate selection of tree species for reforestation in conservation programs and the possible negative effects of selective logging in primary forests. Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp.
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conservation of Epiphyte diversity in an andean landscape transformed by human land use
Conservation Biology, 2009Co-Authors: Nils Koster, Jurgen Nieder, Karoline Friedrich, Wilhelm BarthlottAbstract:Epiphytes are diverse and important elements of tropical forests, but as canopy-dwelling organisms, they are highly vulnerable to deforestation. To assess the effect of deforestation on Epiphyte diversity and the potential for Epiphyte conservation in anthropogenically transformed habitats, we surveyed the epiphytic vegetation of an Ecuadorian cloud forest reserve and its surroundings. Our study was located on the western slopes of the Andes, a global center of biodiversity. We sampled vascular Epiphytes of 110 study plots in a continuous primary forest; 14 primary forest fragments; isolated remnant trees in young, middle-aged, and old pastures; and young and old secondary forests. It is the first study to include all relevant types of habitat transformation at a single study site and to compare Epiphyte diversity at different temporal stages of fragmentation. Epiphyte diversity was highest in continuous primary forest, followed by forest fragments and isolated remnant trees, and lowest in young secondary forests. Spatial parameters of habitat transformation, such as fragment area, distance to the continuous primary forest, or distance to the forest edge from inside the forest, had no significant effect on Epiphyte diversity. Hence, the influence of dispersal limitations appeared to be negligible or appeared to operate only over very short distances, whereas microclimatic edge effects acted only in the case of completely isolated trees, but not in larger forest fragments. Epiphyte diversity increased considerably with age of secondary forests, but species assemblages on isolated remnant trees were impoverished distinctly with time since isolation. Thus, isolated trees may serve for recolonization of secondary forests, but only for a relatively short time. We therefore suggest that the conservation of even small patches of primary forest within agricultural landscape matrices is essential for the long-term maintenance of the high Epiphyte diversity in tropical cloud forests.
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large scale diversity patterns of vascular Epiphytes in neotropical montane rain forests
Journal of Biogeography, 2004Co-Authors: Wolfgang Kuper, Holger Kreft, Jurgen Nieder, Nils Koster, Wilhelm BarthlottAbstract:Aim Epiphytes contribute up to 30% to the number of vascular plant species in certain global biodiversity hotspots, e.g. the Ecuadorian Andes. However, their large scale diversity patterns are still discussed on the base of results from a few, local Epiphyte inventories. Consequently, explanatory models on Epiphyte diversity concentrate on the impact of local climate on small scale Epiphyte species richness. Our aim was to analyse large scale elevational patterns of Epiphyte diversity integrating data from different geographic scales. Location Tropical America, with special emphasis on the Ecuadorian Andes. Methods Our study is based on two data sources. First, we analysed the elevational patterns of Epiphyte diversity based on the Catalogue of the Vascular Plants of Ecuador and the Libro Rojo de las Plantas Endemicas del Ecuador. Secondly, the floristic turnover between the Epiphyte inventories of seven montane and four lowland study sites in the Neotropics was analysed. Results The floristic turnover between Neotropical montane Epiphyte floras is higher than the one between lowland Epiphyte floras. Montane study sites located only a few kilometres apart from each other show considerable differences in their Epiphyte species inventories. Irrespectively of their similar dispersal mode, the floristic turnover is much higher for orchids than for Pteridophyta. The Orchidaceae are the species richest group in all of the examined 11 Neotropical Epiphyte floras. At the larger scale of the Ecuadorian Flora, c. 50% of the species in the elevational zone with maximum Epiphyte diversity (between 1000 and 1500 m) are orchids. Elevational patterns of Epiphyte diversity strongly reflect patterns of Orchidaceae. Main conclusions Our results support the observation of a 'mid-elevation bulge' of Epiphyte diversity by Gentry and Dodson. It has been frequently shown that the high humidity in mid-elevations is suitable to maintan a high Epiphyte species richness. Our findings show that in addition, large scale Epiphyte diversity in montane rain forest is increased by the high floristic turnover at local and regional scale. Based on the importance of Orchidaceae for Epiphyte diversity, we discuss that speciation processes corresponding to the highly diverse environment are a driving force for endemism, floristic heterogeneity and consequently for large scale Epiphyte species richness in montane forests.
Nalini M. Nadkarni - One of the best experts on this subject based on the ideXlab platform.
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response of non vascular Epiphytes to simulated climate change in a montane moist evergreen broad leaved forest in southwest china
Biological Conservation, 2012Co-Authors: Liang Song, Nalini M. NadkarniAbstract:Interest in the potential effects of global climate change on forest ecosystems is increasing, but little is known about their effects on canopy communities, even though their reliance on atmospheric moisture and nutrients suggest that they are sensitive to current predictions of climatic change. We conducted a field experiment to assess the potential impacts of predicted climate change on the growth and health of four common non-vascular Epiphytes at three elevations in a subtropical montane moist evergreen broad-leaved forest in southwest China. Even slight changes in climate resulted in remarkably reduced rates of growth and detrimental effects on the health of the transplanted Epiphyte species over 2 years. Non-vascular Epiphytes in this forest type respond much more rapidly to changes in water availability than terrestrial trees. The non-vascular lichen, Nephromopsis pallescens, is highly sensitive to changes in moisture and temperature, and could be adopted as a climate change indicator. Non-vascular Epiphyte species may be negatively affected or even severely damaged in the future in subtropical montane forests, as climate conditions are predicted to be warmer and drier. This experiment confirms previous model projections and implies that conservation efforts to maintain the stability and resiliency of montane forest ecosystem to climate change should include Epiphyte communities.
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a protocol for sampling vascular Epiphyte richness and abundance
Journal of Tropical Ecology, 2009Co-Authors: Jan H D Wolf, Robbert S Gradstein, Nalini M. NadkarniAbstract:The sampling of Epiphytes is fraught with methodological difficulties. We present a protocol to sample and analyse vascular Epiphyte richness and abundance in forests of different structure (SVERA). Epiphyte abundance is estimated as biomass by recording the number of plant components in a range of size cohorts. Epiphyte species biomass is estimated on 35 sample-trees, evenly distributed over six trunk diameter-size cohorts (10 trees with dbh > 30 cm). Tree height, dbh and number of forks (diameter > 5 cm) yield a dimensionless estimate of the size of the tree. Epiphyte dry weight and species richness between forests is compared with ANCOVA that controls for tree size. SChao1 is used as an estimate of the total number of species at the sites. The relative dependence of the distribution of the Epiphyte communities on environmental and spatial variables may be assessed using multivariate analysis and Mantel test. In a case study, we compared Epiphyte vegetation of six Mexican oak forests and one Colombian oak forest at similar elevation. We found a strongly significant positive correlation between tree size and Epiphyte richness or biomass at all sites. In forests with a higher diversity of host trees, more trees must be sampled. Epiphyte biomass at the Colombian site was lower than in any of the Mexican sites; without correction for tree size no significant differences in terms of Epiphyte biomass could be detected. The occurrence of spatial dependence, at both the landscape level and at the tree level, shows that the inclusion of spatial descriptors in SVERA is justified.
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biomass and nutrient pools of canopy and terrestrial components in a primary and a secondary montane cloud forest costa rica
Forest Ecology and Management, 2004Co-Authors: Nalini M. Nadkarni, Douglas Schaefer, Teri J Matelson, Rodrigo SolanoAbstract:Abstract Canopy-dwelling Epiphytes and their associated dead organic matter exist as complex subsystems of many forests, but they have only rarely been quantified in the context of the whole ecosystem. We assessed the biomass and nutrient capital of canopy-dwelling and terrestrially rooted components of a primary and an adjacent secondary montane forest in Monteverde, Costa Rica. Total aboveground terrestrially rooted biomass (dry weight) was 490.1 and 151 t ha−1 in the primary and secondary forest, respectively. The primary forest supported a total canopy biomass of 33.1 t ha−1; the secondary forest supported only 0.5% of that, 0.2 t ha−1. Trunk and branch Epiphyte biomass in the primary forest was over 40 times and 100 times greater than trunk and branch Epiphyte biomass in the secondary forest. The bulk (ca. 95%) of the ecosystem biomass is trunk and branch wood, which is slower to decompose than the non-woody, labile components of foliage and non-woody Epiphytes. In contrast to the primary forest, where dead organic matter (crown humus, intercepted litterfall) comprised over 60% of the total epiphytic material, there were only trace amounts in the secondary forest. The important ecosystem roles performed by this material in the primary forest (e.g., retention of atmospheric nutrients, habitat for canopy invertebrates, and substrate for wildlife and bird foraging) are virtually absent in the secondary forest canopy.
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potential effects of climate change on canopy communities in a tropical cloud forest an experimental approach
Oecologia, 2002Co-Authors: Nalini M. Nadkarni, Rodrigo SolanoAbstract:Global climate change models predict reduced cloud water in tropical montane forests. To test the effects of reduced cloud water on Epiphytes, plants that are tightly coupled to atmospheric inputs, we transplanted Epiphytes and their arboreal soil from upper cloud forest trees to trees at slightly lower elevations that are naturally exposed to less cloud water. Control plants moved between trees within the upper site showed no transplantation effects, but experimental plants at lower sites had significantly higher leaf mortality, lower leaf production, and reduced longevity. After the Epiphytes died, seedlings of terrestrial gap-colonizing tree species grew from the seed banks within the residual mats of arboreal soil. Greenhouse experiments confirmed that the death of Epiphytes can result in radical compositional changes of canopy communities. Thus, tropical montane Epiphyte communities constitute both a potentially powerful tool for detecting climate changes and a rich arena to study plant/soil/seed interactions under natural and manipulated conditions. This study also provides experimental evidence that the potential effects of global climate change on canopy and terrestrial communities can be significant for cloud forest biota. Results suggest there will be negative effects on the productivity and longevity of particular Epiphytes and a subsequent emergence of an emerging terrestrial component into the canopy community from a previously suppressed seed bank.
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nitrogen 15 natural abundance in a montane cloud forest canopy as an indicator of nitrogen cycling and Epiphyte nutrition
Oecologia, 2002Co-Authors: Peter Hietz, Wolfgang Wanek, R Wania, Nalini M. NadkarniAbstract:Nutrients obtained by Epiphytes may either be of atmospheric origin or from organic matter in the canopy, which decomposes to form canopy soil on large branches. We hypothesised that the N supply for Epiphytes on small branches was lower, and a larger proportion provided by rainwater, than for Epiphytes rooting in canopy soil. We tested this by measuring the N concentration and isotopic composition in terrestrial and canopy soil and in various canopy compartments of a Costa Rican cloud forest. In general, Epiphytes on small branches without canopy soil had lower N foliar concentrations and δ15N signals than plants rooted in canopy soil, suggesting that the former receive a higher proportion of N directly from the rain. Epiphytes on small branches also had less negative δ13C values, indicating more frequent water stress. Epiphytes had lower δ15N values (–3.9±2.3‰) than ground-rooted trees (–1.1±1.6‰), and canopy soil had lower values (0.7±1.2‰) than terrestrial soil (3.8±0.7‰). Assuming that the isotopic effect of terrestrial and canopy soil organic matter formation is similar, our findings support earlier results showing that canopy soil is derived mainly from Epiphytes, with only minor inputs from host tree matter. Thus, the Epiphyte N cycle appears to be largely detached from the tree-soil cycle. Epiphylls on leaves of understorey shrubs had higher δ15N signals than cryptogams in the upper canopy, as a result of either 15N accumulation in throughfall or increased N2 fixation. The correlation between epiphyll and understorey host leaf δ15N suggests some exchange of N between epiphylls and host leaves. Differences between Epiphyte groups also appear to be related to uptake of N through mycorrhizas or N2 fixation. Thus, the source and quantity of N supply is highly variable, depending on the systematic group and canopy position.