In a Subtropical Montane Forest Ecosystem in

Tropical Montane Cloud Forests

Bryologist, 2009

Bryophyte communities are highly sensitive to moisture and/or humidity levels. Most studies on the subject focus on bryophytes on either tree or ground habitats and do not consider how bryophytes partition themselves across both ground and epiphytic substrates within the same forest. Sampling mesic temperate forest sites of the same physiognomy from two Tasmanian regions with slightly different moisture levels (a wetter northwest versus a drier northeast region), we examine various aspects of the community structure (overall liverwort and moss cover; species richness; and liverwort to moss ratios) of both tree and ground communities with respects to moisture availability. We then test the hypothesis that a wetter site will exhibit a greater magnitude of bryophytes inhabiting both tree and ground habitats. Results of the analyses show that the ground habitat in the northwest sites exhibited a significantly higher mean species richness, higher overall and mean liverwort to moss ratio, and a higher liverwort cover than the northeast sites. This suggests that the northwest had a more ameliorated ground microclimate than the northeast. In terms of habitat partitioning, a significantly higher percentage of taxa occupied both tree and ground habitats in the northwest, compared to the northeast, which exhibited a higher percentage of taxa restricted to trees. It is proposed that within a single vegetation type, a higher site moisture level may create microclimates conducive to more bryophyte species in both tree and ground habitats, especially the latter, thereby enabling taxa to colonize and coexist on both substrates more freely.

Biotropica, 2005

We investigated ecophysiological and morphological traits affecting light and water use of four commercially important pendant epiphytic bryophyte species in a montane oak-bamboo forest in Costa Rica. Predictions based mostly on ecophysiological studies of temperate bryophytes and vascular plants were experimentally tested on tropical montane bryophyte species ranked on the basis of their distributions in the canopy from the most protected (1) to the most exposed sites (4):

Biogeosciences Discussions, 2019

In the Amazonian rain forest, major parts of trees and shrubs are covered by epiphytic cryptogams of great taxonomic variety, but their relevance in biosphere-atmosphere exchange, climate processes, and nutrient cycling are largely unknown. As cryptogams are poikilohydric organisms, they are physiologically active only under moist conditions. Thus, information on their water content, as well as temperature and light conditions experienced by them are essential to analyzing their impact on local, regional, and even global biogeochemical pro-5 cesses. In this study, we present data on the microclimatic and ecophysiological conditions of epiphytic bryophytes along a vertical gradient and combine these with mesoclimate data collected at the Amazon Tall Tower Observatory (ATTO) in the Amazonian rain forest between October 2014 and December 2016. While the monthly average mesoclimatic ambient light intensities above the canopy revealed only minor variations, the light intensities incident on the bryophytes showed different patterns at different heights, probably depending on individual shading by vegetation. At 1.5 m height, monthly average light intensities were similar throughout the year and individual values were extremely low, exceeding 5 µmol m-2 s-1 photosynthetic photon flux density only during 8 % of the time. Temperatures showed only minor variations throughout the year with higher values and larger height-dependent differences during the dry season. Water contents of bryophytes varied depending on precipitation and air humidity. Whereas bryophytes at higher levels were affected by frequent wetting and drying events, those close to the forest floor remained wet over longer time spans during the wet seasons. Based on estimates of the potential duration of net photosynthesis and dark respiration, our data suggest that water contents are decisive for overall physiological activity, and light intensities determine whether net photosynthesis or dark respiration occurs, whereas temperature variations are only of minor relevance in this environment. In general, bryophytes growing close to the forest floor are limited by light availability, while those growing in the canopy must withstand larger variations in microclimatic conditions, especially in the dry season. Measurements of CO2 gas exchange are essential to elucidate their physiological activity patterns in greater detail. the rain forests are endangered by human activities, such as clear-cutting of primary forests for plantations, livestock, and settlement of residential and industrial areas, but also by atmospheric pollution (Koren et al., 2014; Rosenfeld et al., 2008; ter Steege et al., 2015). Up to now, ~ 16 000 tree species have been estimated for the Amazon (ter Steege et al., 2013), but the impact of anthropogenic activities on these numbers is highly uncertain. Similarly, it is also hard to predict, to which extent the ongoing and envisioned changes will still ensure its eco-5 logical services as "green lung" and carbon sink of planet Earth (Soepadmo, 1993). Apart from vascular plants, forming a predominant fraction of the biomass within this biome, there are also cryptogamic photoautotrophs comprising bryophytes, algae, lichens, and cyanobacteria, which form communities together with heterotrophic fungi, other bacteria, and archaea. These communities can colonize different substrates, such as soil, rock, and plant surfaces in almost all habitats throughout the world (Büdel, 2002; Elbert et al., 2012; Freiberg, 1999). In the Amazon rain forest, cryptogamic communities mainly occur epiphytically on the stems, branches, and even leaves of trees, and in open forest fractions they may also occur on the soil. In 2013, 800 species of mosses and liverworts, 250 lichens species, and 1 800 fungal species have been reported for the Amazon region

Biotropica, 1998

To understand the ecological roles of epiphytic bryophytes in the carbon (C) and nltrogen (N) cycles of a tropical montane forest, we used samples In enclosures to estimate rates of growth, net and N accumulation by shoots In the canopy, and litterbags, to est~mate rates of decomposition and N dynamics of epiphytic bryophytc litter In the canopy and on the forest floor in Monteverde, Costa kca. Growth of eprphyric bryophytes was estimated at 30.049.9 percent/yr, net product~on at 122-203 glm'lyr, and N accumulation at 1.8-3.0 g Nlm'lyr. Cumulative mass loss from litterbags aher one and two years in the canopy was 17 ? 2 and 19 2 2 percent (mean 2 I SE) of initial sample mass, respectively, and mass loss from litter and green shoots in litterbags aher one ycar on the forest floor was 29 ? 2 and 45 t-3 percent, respecrively. Approximately 30 percent of the Initial N mass was released rapidly from litter in both locations. Nitrogcn loss from green shoots on the forest floor was greater; about 47 percent of the Initial N mass was lost wirhln thc first three months. Therc was no evidence for net N immobilization by litter or green shoots, but thc remaining N in litter was apparently rcdcirrant. Annual nct accumulation of C and N by epiphytic bryophyrcs was estimated at 37-64 g Clm21yr and 0.8-1.3 g Nlm2lyr. respectively. Prcvious rcscarch at this site indicated that epiphytic bryophytes retain inorganic N from atmospheric deposition to the canopy. Therefore, they play a major role in ransformlng N from mobile ro highly recalcitrant forms in this ccosystcm.

Canadian Journal of Forest Research, 2009

... 2001; Chang et al. 2002; Pypker et al. 2006) and recent studies have stressed their potential as indicators of “old-growth-forest” conditions (Drehwald 2001; McGee and Kimmerer 2002;Acebey et al. ... 1991; Boudreault et al. 2000; Acebey et al. 2003; Hylander et al. ...

Several sampling techniques for estimating abundance of non-vascular epiphytes, including bryophytes, have been developed over the past decade. The efficacy of those techniques, however, has never been investigated. The present study examines three sampling techniques: ladder quadrats, 10 x 10 cm quadrats at intervals of 40 cm, and a 10 cm wide strip around the stem. We found the use of 10 x 10 cm quadrats at intervals of 40 cm to be the most effective and efficient sampling method for quantifying bryophyte cover.

Ecological Indicators, 2012

Climatic conditions are a prime candidate to explain local patterns of biodiversity and consequently there is great need of on-site climatic measurements. Among them, however, air humidity is notoriously difficult and time-consuming to measure, and it has been proposed that the epiphytic bryophyte cover can be used as an indicator of long-term air humidity conditions. Here we explore the utility of visually estimated epiphytic bryophyte cover on large canopy branches as a proxy for air humidity at 26 study sites in tropical forests where we measured microclimate for at least 12 months. Across all sites, bryophyte cover was weakly related to relative air humidity (R 2 = 0.17), but when we separated highland (1800-3500 m elevation) from lowland (<1800 m) sites, relative air humidity showed significant and distinct relations to bryophyte cover (R 2 = 0.36-0.62), whereas temperature was related to bryophyte cover only in the lowlands (R 2 = 0.36). We conclude that epiphytic bryophyte cover can be used as a proxy for air humidity if temperature and elevation are taken into account within a circumscribed study region, but might not be applicable for comparisons across extensive elevational gradients or wide differences in temperature.

Plant Ecology, 2011

This study explores the host tree preferences of epiphyte bryophyte communities in two key types of evergreen cloud forests on La Gomera (Canary Islands, Spain): ericaceous versus broadleaved laurel forest. By comparing two pairs of tree species (Erica arborea and Myrica faya vs. Ilex canariensis and Laurus novocanariensis) that occur in both forest types, we quantitatively examined whether epiphyte-host relationships change with the type of forest. In 51 ancient forest stands, the low-trunk bryophyte composition on the two host tree groups was analysed with both non-parametric procedures and ordination analyses. Our results highlight that the influence of local environmental conditions on the structuring of epiphyte communities may be different depending on the host tree identity. Whilst the epiphyte composition of the host tree group formed by I. canariensis and L. novocanariensis differed significantly between forest types depending on solar exposure, we failed to find variations for the other host tree group, excepting in those localities wherein mist precipitation was extremely high. Our findings highlight the importance of the natural diversity of tree species along environmental gradients, as well as of water availability at different spatial scales for epiphytic bryophytes in montane cloud forests.

1. Coarse woody debris (CWD) serves as habitat for diverse and rare taxa in forest systems. Because the abundance of mosses appears to be correlated with log size and stage of decay, many have suggested that CWD serves as a moisture reservoir, ensuring a humid microclimate and facilitating moss growth, but no one has tested this connection. Intact forest canopies are also thought to maintain humid conditions that benefit moss growth. If microclimatic regulation is the primary mechanism contributing to high moss abundance on CWD, then epixylic moss growth should increase with the capacity of the log moisture reservoir, and the importance of the reservoir size should increase with canopy opening. 2. Three types of synthetic logs, identical in size and shape but differing in moisture capacity, and two natural substrates, well-decayed birch and cedar logs, were used to test the effects of log moisture capacity on growth of Dicranum flagellare under thinned and intact canopies of a spruce plantation over 20 months. 3. Surface humidity was positively associated with moisture capacity, but did not reach the water compensation point outside of precipitation events. Under a closed forest canopy, moss growth was negligible across all log types. Under an open forest canopy, moss growth was greater on natural substrates than synthetic ones, and negatively related to moisture capacity. Coarse woody debris facilitates a sufficiently humid surface for only a short time after precipitation , presumably when a film of liquid water is maintained near the surface. 4. For D. flagellare, canopy condition is a more accurate predictor of growth than CWD-moisture capacity; any beneficial properties of CWD appear to be lessened by a dense forest canopy (as in silvicultural plantations), probably because it reduces access to liquid water from precipitation. 5. We propose that the surface moisture availability of CWD depends on optimal depth of a 'resisting layer' below the log surface, representing a tradeoff between water retention and loss (via percolation or runoff at extremely deep vs. shallow resisting layer depth). Coarse woody debris may possess microclimate-regulating traits that benefit moss growth, but it does not appear to act as a moisture capacitor.

Ecological Indicators

Climatic conditions are a prime candidate to explain local patterns of biodiversity and consequently there is great need of on-site climatic measurements. Among them, however, air humidity is notoriously difficult and time-consuming to measure, and it has been proposed that the epiphytic bryophyte cover can be used as an indicator of long-term air humidity conditions. Here we explore the utility of visually estimated epiphytic bryophyte cover on large canopy branches as a proxy for air humidity at 26 study sites in tropical forests where we measured microclimate for at least 12 months. Across all sites, bryophyte cover was weakly related to relative air humidity (R2 = 0.17), but when we separated highland (1800–3500 m elevation) from lowland (&lt;1800 m) sites, relative air humidity showed significant and distinct relations to bryophyte cover (R2 = 0.36–0.62), whereas temperature was related to bryophyte cover only in the lowlands (R2 = 0.36). We conclude that epiphytic bryophyte co...

Managed laurel forests in the Canary Islands have undergone clear-cutting with rotation periods of less than 30 y. Forest owners have recently requested a drastic reduction in the cutting interval. The effects of this new harvesting cycle on organisms like epiphytic bryophytes are not well known.

Annals of Forest Science, 2009

Managed laurel forests in the Canary Islands have undergone clear-cutting with rotation periods of less than 30 y. Forest owners have recently requested a drastic reduction in the cutting interval. The effects of this new harvesting cycle on organisms like epiphytic bryophytes are not well known.

PeerJ, 2020

Epiphytic bryophytes (EB) are some of the most commonly found plant species in tropical montane cloud forests, and they play a disproportionate role in influencing the terrestrial hydrological and nutrient cycles. However, it is difficult to estimate the abundance of EB due to the nature of their “epiphytic” habitat. This study proposes an allometric scaling approach implemented in twenty-one 30 × 30 m plots across an elevation range in 16,773 ha tropical montane cloud forests of northeastern Taiwan to measure EB biomass, a primary metric for indicating plant abundance and productivity. A general allometry was developed to estimate EB biomass of 100 cm2 circular-shaped mats (n = 131) with their central depths. We developed a new point-intercept instrument to rapidly measure the depths of EB along tree trunks below 300 cm from the ground level (sampled stem surface area (SSA)) (n = 210). Biomass of EB of each point measure was derived using the general allometry and was aggregated ac...

Epiphytic bryophytes (EB) are some of the most commonly found plant species in tropical montane cloud forests, and they play a disproportionate role in influencing the terrestrial hydrological and nutrient cycles. However, it is difficult to estimate the abundance of EB due to the nature of their “epiphytic” habitat. This study proposes an allometric scaling approach to measure EB biomass, implemented in 16,773 ha tropical montane cloud forests of northeastern Taiwan. A general allometry was developed to estimate EB biomass of 100 cm2 circular-shaped mats (n = 131) and their central depths. A point-intercept instrument was invented to measure the depths of EB along tree trunks (n = 210) below 3-m from the ground level (sampled stem surface area [SSA]) in twenty-one 30 × 30 m plots. Biomass of EB of each point measure was derived using the general allometry and was aggregated across each SSA, and its performance was evaluated. Total EB biomass of a tree was estimated by referring to ...