Lowland Cloud Forest Research Articles

Epiphyllous Bryophyte Diversity in Lowland Rain Forest and Lowland Cloud Forest of French Guiana

Diversité des bryophytes épiphylles dans une forêt pluviale de plaine et une forêt nuageuse de plaine de Guyane française. La forêt tropicale nuageuse de plaine (LCF) est seulement connue en Guyane française mais pourrait être plus répandue dans les tropiques. Elle se distingue botaniquement de la forêt pluviale de plaine (LRF) par la diversité et la composition des groupements d'épiphytes présents dans la canopée. Pour faciliter la détection de la LCF, des indicateurs fiables au niveau du sol sont nécessaires. Une première comparaison de la diversité des bryophytes épiphylles dans le sous-bois de la LRF et de la LCF de Guyane française a révélé une richesse en espèces cinq fois plus élevée dans la LCF. L'abondance des espèces était également beaucoup plus élevée dans la LCF. L'efficacité de l'échantillonnage était d'environ 80 % dans chaque type de forêt. Six espèces (11 %) ont été trouvées dans les deux types de forêt, 43 espèces (80 %) ont été trouvées uniquement dans la LCF et cinq espèces (9 %) uniquement dans la LRF. Les espèces exclusives à la LCF n'étaient cependant pas uniques à la forêt nuageuse à une plus grande échelle. Les Lejeuneaceae Rostovzev ont contribué à 100 % de la diversité épiphylle dans la LRF et à 70 % dans la LCF. La plus faible représentation des Lejeuneaceae dans la LCF concorde avec le fait que la diversité des espèces épiphytes dans la LCF est similaire à celle des forêts montagnardes. La diversité des bryophytes épiphylles, plus que la composition des espèces, peut être un outil approprié pour la reconnaissance de la forêt nuageuse de plaine au niveau du sol, sans implication de l'escalade des arbres.

A new fog and low stratus retrieval for tropical South America reveals widespread fog in lowland forests

Fog-driven epiphyte-rich tropical cloud forests were long believed to be restricted to mountainous regions. Recent studies have shown the occurrence of such forest types in the lowlands of French Guiana, where early morning radiation fog was shown to modify the water and energy cycles at the canopy level of the tropical lowland rain forest (Gehrig-Downie et al., 2012; Obregon et al., 2011). Since this newly discovered Tropical Lowland Cloud Forest (TLCF) harbours a unique biodiversity comparable to mountain cloud forests, knowledge of its spatial distribution across tropical lowland forests is of large ecological interest, but so far fully unknown. A prerequisite to detect potential TLCF stands is knowledge on the spatial occurrence of fog/low stratus clouds (FLS) over longer time scales, indicating fog frequency. We address this need on a continental scale by presenting the first spatially-explicit, high-resolution product on nocturnal FLS occurrence over the entire tropical lowland rain forest area of South America. The product is based on a new FLS retrieval scheme that uses brightness temperature (BT) information of night-time satellite images acquired by the Aqua Moderate Imaging Spectroradiometer (Aqua MODIS). Since landforms substantially influence small-scale FLS development, we used a dynamic threshold technique depending on the spatially variable subpixel information on landform suitability for FLS generation. The product was successfully validated against in-situ visibility measurements combined with a plausibility analysis based on the published but scarce fog observations over the Amazon. The independence of the new algorithm from measured total precipitable water (TPW) is an improvement over existing procedures that are limited to the availability of these ancillary data. The FLS frequency map for the entire tropical lowland forest of South America derived from over 52,000 scenes (18 years from 2003 to 2020 inclusive) indicates that FLS is widespread, though spatially differentiated, throughout the tropical lowland forests of South America, providing suitable environmental conditions for the TLCF. This knowledge on the spatial distribution of potential TLCF is of major importance for conservation efforts. The new FLS scheme is applicable to all tropical lowland forests and can therefore support global conservation efforts of the valuable TLCF ecosystems.

A new and showy species of Lepanthes (Orchidaceae: Pleurothallidinae) from North-Western Ecuador

A new species of Lepanthes from north-western Ecuador is presented here. Lepanthes mashpica is similar to L. satyrica, with a long, descending, triangular process of the body of the lip but different in the simple and acute appendix versus the vertically bilobed appendix of L. satyrica. The species was found growing in several locations of Mashpi Reserve, a low-land cloud forest close to Quito.
 
 Keywords: Ecuadorean orchids, Lepanthes mashpica, Lepanthes satyrica, Mashpi Reserve

THE LICHENS DIVERSITY IN TRIANGULATION OF ALAS PURWO NATIONAL PARK, EAST JAVA

<p>The lichen flora of tropical areas is still much underworked Java in general and Alas Purwo in East Java for specially is no exception. Alas Purwo National Park is representative of a typical lowland tropical rain forest ecosystem in Java. . It is famous with peculiar and endemic species of plant include sawo kecik (Manilkara kauki) and manggong bamboo (Gigantochloa manggong). , beside among the other plants also ketapang (Terminalia cattapa), nyamplung (Calophyllum inophyllum), kepuh (Sterculia foetida), and keben (Barringtonia asiatica). Moreover, in lowland tropical rain forest ecosystem have reported the lichens species diversity is very high and may include over 200 species in 1 ha. There is no reported have found concerning the lichens richness in Alas Purwo. Recently preliminary study of Lichens diversity have been done at triangulation Zone Alas Purwo National Park , East Java. The lichens of the study area have not been treated comprehensively. We explored the lichenological characteristics of putative”tropical lowland cloud forest” (LCF) in a lowland area (0–20ma.s.l.) near Triangulation using macrolichens (cortocoulous species) as indicator taxa We analyzed lichen diversity on 20 trees in two 0,25 ha plots. In tropical lowland forests, corticolous green algal lichens are abundant and highly diverse. This may be related to adaptation to prevailing microenvironmental conditions including, for example, high precipitation and low light intensities. In the understory of a tropical lowland rain forest in Alas Purwo , we studied the morphology and anatomy of corticolous lichens and microcristal test. We found that from Tetrasigma sp , Serbella otodans, Hemandia feltata Baringtonia aciatika Pandanaceae Manilcara cauci Swetinia mahagoni trees there are 30 species of lichens, dominated by Dyorigma sp Graphis and Glyphis from familia of Graphidaceae and Dirinaria Physcia Pyxine Ramalina from familia of Parmeliaceae. The thallus calour was variety from Green-grey, Green-bllue, green, light green, grey, brown, dark green to orange. They have vegetative as wel as generative reproduction such as isidia, soralia, soredia, chypellae, histerothecia, perithecia,and apothecia. The lichenic acids contain such as gyrophoric acid, barbatic acid, usnic acid, atranorin, acid, divaricatic acid and lecanoric acid, </p><p><strong>Keywords</strong>: Alas Purwo, lichens and lichenic acid.</p>

The potential distribution of tropical lowland cloud forest as revealed by a novel MODIS-based fog/low stratus night-time detection scheme

Fog is a crucial driver of epiphyte richness in tropical montane cloud forests but its spatial occurrence and role in tropical lowland areas is poorly understood. Recent studies in French Guiana have reported high epiphyte richness in previously undescribed “tropical lowland cloud forest” (LCF) due to radiation fog. Here, we analyze the spatial extent of fog/low stratus (FLS) in lowland forests of French Guiana using the frequency distribution by means of night-time MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data for the years 2007–2010. The analysis is based on a newly developed dynamic threshold-test method relying on brightness temperature differences between thermal and mid-infrared bands. Individual thresholds for the discrimination between fog/low stratus and cloud-free pixels were retrieved by radiative transfer calculations and validated using discriminant analysis. The thresholds dynamically depend on total precipitable water (TPW) and the terrain-induced maximum possible sub-pixel fog coverage. The results of the new retrieval were validated using in-situ data and compared to results from existing fog detection algorithms, showing an improvement of the new detection scheme regarding the capability to detect sub-pixel fog coverage under varying TPW. FLS frequency maps derived from the novel fog classification scheme indicate a widespread distribution of night-time fog in river valleys, marking a multitude of potential areas for LCF throughout French Guiana. LCF is probably not only a local phenomenon but also may be widely distributed in river valleys in the lowland tropics, with significant consequences for biodiversity mapping in tropical lowland areas.

Interpreting bryophyte stable carbon isotope composition: Plants as temporal and spatial climate recorders

Bryophytes are unable to control tissue water content although physiological adaptations allow growth in a wide range of habitats. Carbon isotope signals in two mosses (Syntrichia ruralis and Chorisodontium aciphyllum) and two liverworts (Conocephalum conicum and Marchantia polymorpha), whether instantaneous (real time, Δ13C), or organic matter (as δ13COM), provide an assimilation-weighted summary of bryophyte environmental adaptations. In mosses, δ13COM is within the measured range of Δ13C values, which suggests that other proxies, such as compound-specific organic signals, will be representative of historical photosynthetic and growth conditions. The liverworts were photosynthetically active over a wider range of relative water contents (RWC) than the mosses. There was a consistent 5‰ offset between Δ13C values in C. conicum and M. polymorpha, suggestive of greater diffusion limitation in the latter. Analysis of a C. aciphyllum moss-peat core showed the isotopic composition over the past 200 years reflects recent anthropogenic CO2 emissions. Once corrected for source-CO2 inputs, the seasonally integrated Δ13COM between 1350 and 2000 A.D. varied by 1.5‰ compared with potential range of the 12‰ measured experimentally, demonstrating the relatively narrow range of conditions under which the majority of net assimilation takes place. Carbon isotope discrimination also varies spatially, with a 4‰ shift in epiphytic bryophyte organic matter found between lowland Amazonia and upper montane tropical cloud forest in the Peruvian Andes, associated with increased diffusion limitation.

Diversity and vertical distribution of epiphytic liverworts in lowland rain forest and lowland cloud forest of French Guiana

Recent evidence is emerging that tropical cloud forests are not restricted to mountains, but may also be found in tropical lowland areas, the so-called ‘tropical lowland cloud forest’ (LCF). LCF occurs in river valleys with high air humidity and morning fog, and is rich in epiphytes. We explored the diversity of bark-inhabiting liverworts in LCF, a group of organisms known to be sensitive indicators of humidity. To test the hypothesis that LCF differs in species richness and species composition from lowland rain forest without fog (LRF), we sampled liverwort diversity in LCF and LRF on 48 whole trees in two sites in French Guiana. Sampling efficiency ( = no. of species found as percentage of estimated total number of species) was about 90% in both forest types. Species richness in LCF was significantly higher than in LRF and species composition differed in all height zones; moreover, LCF had three times more indicator species. Indicators of LCF included shade epiphytes and generalists that occurred also in montane forests, those of LRF were sun epiphytes characteristic of rather dry, open sites. The detected differences in liverwort diversity of LCF and LRF are explained by the more humid conditions in LCF as compared with LRF. A comparison of liverwort richness along elevational gradients in the Neotropics showed that species richness differs more strongly among forest type (rain forest, cloud forest) than among elevation and that lowland cloud forests may be richer in species than montane rain forests. The data indicate that elevational comparisons of bryophyte species diversity in the Tropics should make a distinction between rain forests and cloud forests.

Functional diversity of epiphytes in two tropical lowland rainforests, French Guiana: using bryophyte life-forms to detect areas of high biodiversity

Recent studies have described a new tropical lowland forest type in the Guianas, the tropical lowland cloud forest. It is characterized by an enriched epiphytic species diversity particularly for bryophytes compared to common lowland rainforest, and is facilitated by frequent early morning fog events in valley locations. While the increase in epiphytic species diversity in lowland cloud forests has been documented, uncertainties remain as to (1) how this small scale variation in water supply is shaping the functional diversity of epiphytic components in lowland forests, and (2) whether information on functional group composition of epiphytes might aid in discerning these cloud forests from the common lowland rainforest. We compare the distribution of functional groups of epiphytes across height zones in lowland cloud forest and lowland rain forest of French Guiana in terms of biomass, cover as well as the composition of bryophyte life-forms. Both forests differed in functional composition of epiphytes in the canopy, in particular in the mid and outer canopy, with the cloud forest having a higher biomass and cover of bryophytes and vascular epiphytes as well as a richer bryophyte life-form composition. Bryophyte life-forms characteristic for cloud forests such as tail, weft and pendants were almost lacking in the canopies of common rain forest whereas they were frequent in lowland cloud forests. We suggest that ground-based evaluation of bryophyte life-form composition is a straightforward approach for identifying lowland cloud forest areas for conservation, which represent biodiversity hotspots in tropical lowland forests.

Epiphyte Biomass and Canopy Microclimate in the Tropical Lowland Cloud Forest of French Guiana

Recent work on bryophyte diversity in lowland forests of northern South America has suggested the existence of a new type of cloud forest, the ‘tropical lowland cloud forest’ (LCF). LCF occurs in river valleys in hilly areas with high air humidity and morning fog, and is rich in epiphytes. We explored epiphyte abundance and canopy microclimate of LCF in a lowland area (200–400 m asl) near Saul, central French Guiana. We analyzed the vertical distribution of epiphytic cover and biomass on 48 trees, in LCF and in lowland rain forest (LRF) without fog. Trees in LCF had significantly more epiphytic biomass than in LRF; mean total epiphytic biomass in LCF was about 59 g/m2, and 35 g/m2 in LRF. In all height zones on the trees, total epiphyte cover in LCF exceeded that in LRF, with ca 70 percent mean cover in LCF and ca 15 percent in LRF. During both wet and dry seasons, mean diurnal relative air humidity (RH) was higher in LCF than in LRF, and persistence of high RH after sunrise significantly longer in LCF. We suggest that the prolonged availability of high air humidity in LCF and the additional input of liquid water through fog, enhance epiphyte growth in LCF by shortening the desiccation period and lengthening the period of photosynthetic activity of the plants.

Canopy level fog occurrence in a tropical lowland forest of French Guiana as a prerequisite for high epiphyte diversity

Fog frequency and the meteorological processes leading to fog formation have never been studied in depth in tropical lowland forest areas. This study provides detailed evidence of frequent fog occurrence in lowland valleys of central French Guiana. Fog frequency showed a clear diurnal course, with a maximum before sunrise; average fog duration was 4.6 h. The diurnal course of visibility was positively correlated with the diurnal course of humidity in the above-canopy air. Fog persistence correlated significantly with atmospheric parameters during the dry season, but not during the rainy season. The main trigger of fog development in the lowland forest seemed to be precipitation, leading to higher soil moisture, greater evapotranspiration and, thus, higher water content of air. An increasing temperature difference between valley and hill sites after sunset, together with more frequent down-slope winds during nights with long fog periods, points at some influence of katabatic flows. The frequent occurrence of fog in the valleys correlated with significantly higher epiphyte diversities in valley forests as compared to hill forests, and supported the occurrence of the hitherto undescribed, epiphyte-rich “tropical lowland cloud forest” (LCF) in the valleys. The higher epiphyte diversity in LCF coincided with significantly higher relative air humidity in LCF than in hill forest. The ecological benefits of fog for the epiphytes in LCF are surplus of moisture and delayed onset of the stress period, particularly in the dry season.

Diversity and vertical distribution of epiphytic macrolichens in lowland rain forest and lowland cloud forest of French Guiana

Abstract Recent work on bryophyte diversity in lowland forests of northern South America has suggested the existence of a new type of cloud forest, the “tropical lowland cloud forest” (LCF). LCF occurs in river valleys with high air humidity and radiation fog, and is rich in epiphytes. We explored the lichenological characteristics of putative LCF in a lowland area (200–400 m a.s.l.) near Saul, central French Guiana, using macrolichens (including large crustose species) as indicator taxa. We analyzed macrolichen diversity on 16 trees in two 1 ha plots, in LCF and in lowland rain forest without fog (LRF). Sampling efficiency was ca. 80% in both forest types. Canopies of both LRF and LCF were richer in lichen species than understory trunks. Species richness of macrolichens was rather similar in the two forest types but species composition was significantly different. Cyanolichen richness in LCF was ca. 2.5 times higher than in LRF; in contrast, LRF had 4 times more species of green-algal Parmeliaceae. Our study suggests that cyanolichens except for Coccocarpiaceae serve as indicators of LCF. We explain the detected diversity patterns by differences in water availability due to fog precipitation and higher humidity. This is indicated by the higher relative air humidity in the lowland cloud forest, which was >6% higher than in the rain forest.

Camillea (Xylariaceae, Ascomycota), including two new species, along a trans-Andean altitude gradient in Ecuador

Two new species of Camillea are described from localities on an east–west transect through Ecuador between the latitudes 1°00’N and 1°00’S. Camillea ovalispora was collected in San Vicente de Huaticocha, an area characterized as humid lowland rainforest and premontane cloud forest; C. unistoma was collected at Cuyabeno, a protected area with black water inundated forest and primary rainforest on terra firme. Further, C. heterostoma var. macrospora is elevated to full species status as C. macrospora. New country records of six Camillea species are annotated from the same east-west transect. These are C. flosculosa, C. fossulata, C. hainesii, C. macrospora, C. scriblita, and C. tinctor. Also, previously recorded species have been annotated with new specimens added. Additionally, six distinct taxa from the transect that appear to be undescribed were included in the analysis; one is partly described but not the others due to insufficient material. The data showed an obvious altitude influence on the distribution and frequency of Camillea species. The diversity of species is lower on the western part of the transect compared to the eastern side, probably due to multiple factors such as differences in search intensity between the two slopes, difference in annual rainfall, and possibly the availability of host plants. Camillea taxa were only found at altitudes below 2,000 m, with the highest diversity below 600 m. Palmae is reported as a new host for Camillea species.