Low Epiphyte Research Articles

Tmesipteris alticola (Psilotaceae), a new fern species endemic to New Caledonia

ABSTRACT Tmesipteris alticola is described here as a new fern species endemic to New Caledonia's Grande Terre. It is a fifth species of Tmesipteris for the territory, and the second endemic. The obovate leaves and conic synangia of T. alticola distinguish it morphologically from all other species of Tmesipteris. Phylogenetic analyses of chloroplast DNA sequences support its distinctiveness, and indicate it is most closely related to T. truncata and T. vieillardii among the sampled species. Tmesipteris alticola is known from only four mountainous locations, all with ultramafic substrates in Province Sud, at elevations of 1200 m–1500 m, where it grows terrestrially or as a low epiphyte, seemingly mostly on ridges or around summits within short-statured cloud forest. We propose a provisional IUCN conservation status of Near Threatened for T. alticola because of its limited known occurrences. Tmesipteris alticola adds to a slew of fern species that have been recently newly described, reinstated, or recorded in New Caledonia.

Effect of seed removal by ants on the host-epiphyte associations in a tropical dry forest of central Mexico.

Seed depredation is recognized as a determining factor in plant community structure and composition. Ants are primary consumers of seeds influencing abundance of epiphytes on trees. This study was conducted in two subunits of a tropical dry forest established on different soil substrates in San Andrés de la Cal, Tepoztlán, in Morelos, Mexico, and experimentally tested whether seed removal activity is higher in tree species with smaller epiphyte loads compared to those with greater epiphyte loads. Five trees were selected at random from six species of trees with high (preferred hosts) or low (limiting hosts) epiphyte loads. Seed removal differed among hosts and different soil substrates in the forest. On relating seed removal to the abundance of arboreal ants, the most consistent pattern was that lower seed removal was related to lower ant abundance, while high seed removal was associated with intermediate to high ant abundance. Epiphyte seed removal by ants influences epiphyte abundance and can contribute considerably to a failure to establish, since it diminishes the quantity of seeds available for germination and establishment.

Bark peeling does not explain the distribution of epiphytes between six phorophyte species of a tropical dry forest of Mexico

Background and aims – Contradictory evidence exists regarding the influence of bark peeling on the distribution of epiphytes among phorophyte species and vertical tree strata. However, there is little experimental evidence. The objectives of this study were to test whether bark-peeling rates differ between vertical strata and between phorophyte species, and whether the peeling rate correlates with epiphyte load among species of phorophytes.Materials and methods – In a tropical dry forest of central Mexico, bark exfoliation rates were measured over a period of 310–322 days in six woody species previously reported with different epiphyte distribution, including Bursera copallifera, B. glabrifolia (phoropytes with high epiphyte load), B. fagaroides, Conzattia multiflora, Ipomoea pauciflora and Sapium macrocarpum (phorophytes with low epiphyte load). In three strata (trunk, inner branches and outer branches) of five individuals of each phorophyte, three areas per individual were marked with paint and with a determined number of small plastic tubes stuck to the bark, in order to easily monitor the speed and quantity of any loss of this marked bark over time. These treatments were replicated on an adjacent pinewood board in order to quantify any loss of painted area or plastic tubes that occurred as a result of deterioration of the marking materials rather than peeling of the marked bark.Key results – The methods used for measuring bark peeling were strongly different. Plastic tubes gave an overestimation of bark peeling in the bark and in the pinewood boards; while paint remained in the pinewood boards, suggesting that paint loss on the bark was caused by peeling. Bark peeling rates differed slightly among the tree species and strata, regardless of whether or not the bark had peeling appearance. No pattern was found between bark peeling rate and the epiphyte load on each host.Conclusions – Our results support previous research which estimated that bark peeling with paint method provides a better estimate of peeling rate. In general, the bark peeling rate was the highest reported in literature for trees in a forest, suggesting that the epiphytes of this forest are adapted to colonize trees with high bark peeling rates. However, this attribute may be less important than others for determining host quality for epiphytes.

Branch mortality influences phorophyte quality for vascular epiphytes

Trees generate resources for other guilds (e.g., lianas), including the production of supporting branches for the establishment of epiphytes. In a tropical dry forest of central Mexico, we studied whether branch mortality is associated with phorophyte quality. For a one-year period, we monitored the survival of branches with and without vascular epiphytes in tree species with high epiphyte loads (Bursera copallifera (Sessé & Moc. Ex DC.) Bullock, Bursera glabrifolia (Kunth.) Engl.) and low (Bursera fagaroides (Kunth) Engl., Conzattia multiflora (B.L. Rob.) Standl., Ipomoea pauciflora M.Martens & Galeotti, Sapium macrocarpum Müll.Arg.). The lowest (C. multiflora) and highest (I. pauciflora) branch mortalities occurred in phorophytes with low epiphyte loads, whereas branch mortality in S. macrocarpum was 60% and in all Bursera species was <25%. In B. copallifera and B. glabrifolia, the highest branch mortality was in branches with epiphytes, suggesting a negative influence of these plants, but mortality was also associated with larger/older branches. At the end of monitoring, 95% of the epiphytes of I. pauciflora were growing on dead branches. We conclude that branch mortality is low in phorophytes with high epiphyte loads; but in phorophytes with low epiphyte loads, branches can be ephemeral or long lasting. Low epiphyte abundances in phorophytes with long-lasting branches can be caused by other traits that remain to be examined (e.g., seed capture).

Dispersal limitation of Tillandsia species correlates with rain and host structure in a central Mexican tropical dry forest.

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.

The influence of regional gradients in climate and air pollution on epiphytes in riparian forest galleries of the upper Fraser River watershed

Epiphyte diversity and abundance were examined along the Fraser River and its tributaries in central-interior British Columbia at varying distances from point-source air pollution discharges. Black cottonwood (Populus balsamifera L. ssp. trichocarpa (Torr. & A. Gray ex Hook.) Brayshaw trunks near discharges in Prince George had comparatively low epiphyte diversity and supported an unusual acidiphilic lichen community, including Tuckermannopsis chlorophylla (Willd.) Hale, Usnea lapponica Vain., and Vulpicida canadensis (Räsänen) J.-E. Mattsson & M.J. Lai. At a greater distance from air pollution sources, a more characteristic flora was observed, including Collema Wigg. spp., Lecidea erythrophaea Flörke, Leptogium (Ach.) Gray spp., Lobaria pulmonaria (L.) Hoffm., Nephroma parile (Ach.) Ach., Peltigera Willd. spp., and Strangospora moriformis (Ach.) Stein. These changes were accompanied by large differences in bark pH; mean values ranged from 3.7 in Prince George to 6.7 in upriver stands for black cottonwoods, from 3.5 to 5.4 for live spruce branches (Picea glauca (Moench) Voss), and from 3.1 to 4.9 for dead spruce branches, respectively. Epiphyte communities proximal to Prince George were characterized by many nitrophilous species. Our data showed a strong covariate influence of climate, with Lobarion community lichens more abundant in the easternmost high-precipitation plots. Numerous provincial- and global-level conservation priority species were found, including Collema quadrifidum D.F. Stone & McCune, newly discovered for Canada; Collema coniophilum Goward, a Species at Risk Act listed species; and provincially at risk Heterodermia speciosa (Wulf.) Trev., Physcia tribacia (Ach.) Nyl., and Santessoniella saximontana T. Sprib., P.M. Jørg. & M. Schultz, mostly in sites distant from air pollution sources.

Benefits and costs of epiphyte management in shade coffee plantations

While epiphytes contribute to the biodiversity and structural complexity of shade coffee, their removal from the shade trees is a common management practice in Latin America. We studied the impact of epiphyte removal on coffee productivity and the potential for epiphyte harvesting in a large coffee plantation (200ha), and measured the supply of naturally fallen epiphytes in two small coffee plantations (<10ha) unsuitable for epiphyte harvesting due to low epiphyte recovery rates following removal. Ten trees were stripped of all epiphytes (E−) and a further ten trees were used as control (E+) in the large coffee plantation. Four coffee plants under each tree canopy were selected and the production of flowers and fruits was registered over two consecutive years. Photosynthetic Active Radiation (PAR), relative humidity and temperature were also measured under the canopy of all 20 trees. To estimate the potential harvest of epiphytic bromeliads in the large coffee plantation, all the plants stripped from the ten trees were recorded. The supply of naturally fallen epiphytes was recorded in ten plots (5×5m) in the two small coffee plantations. From January to June, all fallen plants inside these plots were collected monthly, identified, measured and their condition recorded. Finally, we conducted a cost-benefit analysis of epiphyte management in coffee plantations. Epiphyte removal had a significant positive effect on coffee productivity; coffee plants produced 225% and 366% more flowers and fruits, respectively. Epiphyte removal significantly increased mean PAR, but had no effect on temperature and relative humidity. At the large coffee plantation 48 species of vascular epiphytes were registered, 20 of which were bromeliads. On average 727±227 bromeliad rosettes were recorded per individual tree (considering all bromeliad species). In the small coffee plantations, 33 and 37 vascular epiphyte species were recorded, 21 of which were bromeliads. Approximately 21% of fallen epiphytes at the small coffee plantations were in a condition suitable for commercialization. Considering all the species and only plants in suitable condition, approximately 2252±397 and 1421±166plantsha−1 per month could be collected for commercialization from the small coffee plantations. The potential profits from the sale of bromeliads can be considerable; $ 8923USDha−1y−1 from direct harvesting, and $6857 to $11070USDha−1y−1 from collection from the ground. A controlled rotation system of epiphyte harvesting should be implemented in large coffee plantations in order to allow the recuperation of the epiphytic community. Collection of fallen epiphytes is recommended in the small coffee plantations that represent the majority in Central Veracruz. Appropriate management of epiphytes in shade coffee plantations could contribute to an income diversification for coffee farmers with potential for replication in other countries.

Harpacticoid copepod response to epiphyte load variations in Posidonia oceanica (L.) Delile meadows

AbstractWe conducted a field experiment to assess the response of phytal harpacticoids to nutrient‐driven increases of epiphyte load in Posidonia oceanica meadows. First, we evaluated differences in species richness, diversity and assemblage structure of phytal harpacticoids in P. oceanica meadows with differing epiphyte loads. Secondly, we conducted a field experiment where epiphyte load was increased through an in situ addition of nutrients to the water column and evaluated the responses of the harpacticoid assemblages. We predicted that there would be changes in the harpacticoid assemblages as a result of nutrient‐driven increases of epiphyte load, and that these changes would be of a larger magnitude in meadows of low epiphyte load. Our results show that the harpacticoid fauna (&gt;500 μm) present in P. oceanica meadows in the Bay of Palma comprised taxa which are considered phytal and other less abundant ones previously described as sediment dwellers or commensal on other invertebrate species. Nutrient addition had an overall significant effect on epiphyte biomass and on harpacticoid abundance, diversity and assemblage structure, possibly as a response to the increased resources and habitat complexity provided by epiphytes. The abundance of dominant species at each location was favoured by nutrient addition and in some cases correlated with epiphytic biomass, although never strongly. This may indicate that structural complexity or diversity of the epiphytic cover might be more important than the actual epiphytic biomass for the harpacticoid species investigated. More species‐specific studies are necessary to ascertain this and clarify the relationships between harpacticoids and epiphytes in seagrass meadows. To our knowledge, this is the first account of harpacticoid species associated with P. oceanica leaves and the epiphytic community they harbour in the Mediterranean Sea.

A Comparison of Macroinvertebrate and Epiphyte Density and Diversity on Native and Exotic Complex Macrophytes in Three Vermont Lakes

Abstract Invasion of New England lakes by exotic macrophytes can alter trophic interactions if the invaders host macroinvertebrate and epiphyte communities different from those of the native species they replace. Macroinvertebrate density and diversity appears to increase with macrophyte complexity and epiphytic algae colonization, which are also positively correlated. Because of this confounding effect, we investigated native and exotic macrophyte species of similar complexity in order to answer the question: Does the exotic macrophyte Myriophyllum spicatum have lower epiphyte density and richness that results in lower macroinvertebrate density and diversity than those found on a native species of similar complexity? Using independent-sample t-tests, we investigated this question in mixed macrophyte stands of three Vermont lakes. Holding complexity constant, macroinvertebrate density and diversity was positively related with epiphyte density and richness (r 2 = 0.17 and 0.13, respectively). Generally, M....

Effect of host-bark extracts on seed germination in Tillandsia recurvata, an epiphytic bromeliad

Abstract: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.

Are epiphytes a significant component of intertidal Zostera noltii beds?

The role of epiphytes in an intertidal Zostera noltii seagrass bed in Marennes-Oléron Bay was assessed in comparison with the other main benthic primary producers ( Z. noltii, microphytobenthos) at two bathymetric levels and on a seasonal basis. Assemblage and biomass of epiphytes were studied using scanning electron microscopy (SEM). Z. noltii and its detrital matter followed a typical seasonal pattern: microphytobenthos was present in large quantities throughout the year representing 21% of the total biomass while detrital matter, above-ground parts and below-ground parts accounted for 65, 9 and 5%, respectively. Only two species of epiphytic diatoms, Cocconeis scutellum and Cocconeis placentula, were observed on seagrass leaves. Epiphyte biomass was very low, representing on average less than 0.001% of that of microphytobenthos or leaves. This low epiphyte biomass is linked with the absence of macroalgae and also with the low biovolume of Cocconeis, which formed a monolayer of cells on leaves. This can be explained by the severe conditions of the intertidal and the high leaf turn-over of Z. noltii leaves.

Instrumental neutron activation analysis and inductively coupled plasma mass spectrometry on atmospheric biomonitors

In a biomonitoring study aiming to find alternatives to lower epiphytes as air-quality monitors, lichens and tree bark were exposed at different sites for discontinuous periods of 2 months and continuously. Native lichens were collected as well. The contents for 22 elements were obtained by both instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS). Quality control as asserted by analyzing ISE-921, NIST-1547 and TL-1 was good. Losses of As and Se by volatilization during sample digestion and neutron irradiation were evident; Ca contents by ICP-MS appeared underestimated probably due to the formation of the insoluble fluoride. ICP-MS featured a better precision than INAA. Nonparametric statistics were applied to the ICP-MS replicates, to those determined by INAA, and to compare the results of both techniques. High or even excellent correlations were found between replicates in INAA, whereas, in ICP-MS, Cr and Ta were just fairly or not correlated. As an overall comparison of the techniques, biased results were found for As, Ba, Ce, Cr, Cs, Hf, La, Sc, Se, Ta, and Zn; unbiased results could be found for Ca, Co, Fe, K, Na, Rb, Sb, Sm, Tb, Th, and U.

Top-down and bottom-up stabilizing mechanisms in eelgrass meadows differentially affected by coastal upwelling

Trophic cascades usually regulate structure and dynamics of valuable benthic vegeta- tion communities (e.g. kelp forests, salt marshes), resulting in alternating high and low abundances from predators at the highest level, down through herbivores, to basal producers at the lowest trophic level. While herbivores may have direct strong negative effects on kelp and salt marsh vegetation, grazing invertebrates (mesograzers) within seagrass meadows consume and thus control the biomass of opportunistic epiphyte algae that can outcompete seagrasses for light. Small fish predators, how- ever, may control mesograzer abundances, thus releasing epiphytes from grazing pressure, with resultant widespread losses of seagrasses under eutrophic conditions. In order to assess whether trophic cascades operate in seagrass systems, we compared patterns of abundance and composition of the benthic vegetation community, the associated epifaunal invertebrates, and their predators in eelgrass meadows distributed across a natural gradient of algal productivity. Within this gradient we selected and sampled in summer and winter 3 eelgrass meadows differentially affected by strong coastal upwelling. High mesograzer abundance repeatedly coincided with low epiphyte biomass, emphasizing top-down control of epiphytes, despite high nutrient availability. Consumption of live eelgrass tissue by mesograzers was potentially important at the lower end of the productivity gradi- ent. Alternating patterns of abundances between successive trophic levels under intermediate and high productivity conditions suggest that small predator abundances may ultimately govern the suc- cess of eelgrass in eutrophic meadows. When pipefish were abundant and eelgrass complexity was low, patterns were consistent with a destabilizing trophic cascade. Evidence supporting a trophic cascade dynamic from small fish through to epiphytes may indicate susceptibility of eelgrass systems to higher order interactions.

PIXE ANALYSIS OF BIOLOGICAL SAMPLES FOR ASSESSING AIRBORNE ELEMENTS AT GROUND LEVEL

Biological monitoring through higher plants should be more than just a second choice for air-quality assessment in polluted or dry areas that happen to be devoid of lichens and/or bryophytes. Provided that some of their specifics are accounted for, vascular plants could indeed stand for an actual alternative to lower epiphytes, if not featuring some real advantages – technical, economical and ecological – over them. As a contribution to an evaluation of such an alternative, olive trees (Olea europaea Linn.) have been sampled for their outer bark across two separate areas of mainland Portugal, in a total of 53 collection locations. After suitable procedures, bark samples were put through proton-induced X-ray emission (PIXE) and analyzed for their elemental contents. Nonparametric coefficients (Kendall's) for the spatial variation of S , Ni , Cu and Pb are significant beyond any reasonable, statistical level. There is also a good spatial agreement – sometimes, an excellent one – with lichen trends as an external reference, but for lead, that may suffer from spectral interference though. Further research on material cleansing and pelletising procedures is advisable, especially in what concerns the homogeneity of bark samples for PIXE analysis.

Are lower epiphytes really that better than higher plants for indicating airborne contaminants? An insight into the elemental contents of lichen thalli and tree bark by INAA

Few dedicated attempts at comparing the monitoring performance of lower and higher plants have been carried out so far. As a contribution to such an issue, this paper looks into the relative magnitude of elemental signals from epiphytic lichens (Parmelia spp.) and olive tree (Olea europaea Linn.) bark, determined by INAA. A representative set of 12 elements - As, Ba, Br, Ca, Cl, K, Mg, Mn, Na, Sr, V, Zn - was used for an ab initio comparison between raw data and Rb-normalized data, using distribution-free statistics. Correlation analysis shows an overall improvement in the degree of association between bark and lichen signals when proceeding from raw data to relative enrichment. Apart from Cl, no element is enriched in lichens to a higher extent than in bark. Sign tests are quite conclusive: bark factors are either statistically greater than or equal to lichens'. These findings prompt a word of caution when dealing with biological monitoring data, without accounting for soil, rock or litter inputs into the biomonitors' elemental pools.

Direct measurements of light attenuation by epiphytes on eelgrass Zostera marina

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 238:73-79 (2002) - doi:10.3354/meps238073 Direct measurements of light attenuation by epiphytes on eelgrass Zostera marina Mark J. Brush*, Scott W. Nixon Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882-1197, USA *E-mail: brush@vims.edu ABSTRACT: Declines in the seagrass Zostera marina L. in estuaries and lagoons have been attributed in part to reductions in irradiance reaching the seagrass blades. Epiphytes growing on Z. marina have the potential to attenuate a large fraction of the light that would otherwise reach the blades. This problem has previously been studied by measuring light penetration through homogenized epiphytic slurries or through glass slides fouled with epiphytes. However, the latter may not represent the natural succession or species composition found on live Z. marina leaves and the former does not preserve the structure of the epiphytic complex. Further, past studies have not measured attenuation across the full range of epiphytic densities found in the field. In this study, we measured light penetration across a wide range of epiphytic densities by holding scraped and unscraped Z. marina blades over a submerged light sensor. Results compared well with past studies at low epiphyte densities, with strong reductions in light penetration as density increased. However, at higher densities, penetration leveled off to a relatively constant value as the epiphytes floated out from the edges of the blade. Studies using slurries did not capture this phenomenon and thus predicted decreasing penetration down to 0%. KEY WORDS: Epiphytes · Light attenuation · Seagrass · Zostera marina Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 238. Online publication date: August 08, 2002 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2002 Inter-Research.

Factors associated with dominance of the filamentous green alga Cladophora glomerata

Cladophora glomerata is a filamentous green alga dominant in many large rivers of Montana, U.S.A. I studied several factors which may be associated with nuisance (> 100 mg m −2 chl a, Welch et al., Hydrobiologia 157, 161–168, 1988) C. glomerata biomass: temperature, pH, conductivity, NH 4 +, soluble reactive phosphorus (SRP), NO 3 −, flow and epiphyte load. Samples were collected at 6 sites, ranging from an irrigation ditch to large rivers. Low flow, high NH 4 + and low epiphyte loads were all correlated ( P < 0.05) with high biomass. The negative correlation between flow and biomass was related to low biomass observed during early summer and autumn runoff events, and a peak biomass which occurred during summer low flow. Positive correlations of C. glomerata with NH 4 + were influenced by data from a site receiving secondary sewage effluent. Nevertheless, biomass greater than 100 mg m −2 chl a was observed in other sites with 90% lower nutrient levels. These data indicate that it may be difficult to significantly lower biomass of the common weedy alga C. glomerata in rivers similar to those sampled in this study.