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- Bryophytes from the Azorean native vegetation : their diversity and contribution to ecosystem servicesPublication . Coelho, Márcia Catarina Mendes; Gabriel, Rosalina Maria de Almeida; Ah-Peng, ClaudineOs briófitos são uma componente importante na diversidade de plantas, ocorrendo desde o litoral ao topo da montanha, e são especialmente conspícuos nas florestas açorianas. Essas plantas dependem muito da água disponível no habitat, a qual interceptam pela chuva, orvalho ou nevoeiro, e transportam externamente (capilaridade) e internamente (estruturas celulares). Neste sentido, os briófitos desempenham um papel importante na regulação dos fluxos de água nas florestas pela sua extraordinária capacidade de retenção de água. Contudo, este papel fundamental dos briófitos nos ecossistemas e as suas características fisiológicas não estão totalmente estudados nem quantificados. Este trabalho focou-se num estudo de diversidade e ecofisiologia de briófitos das ilhas Pico e Terceira (Açores, Portugal). Os principais objetivos são: (i) investigar a diversidade e padrão de distribuição das comunidades de briófitos da ilha do Pico, caracterizando os seus habitats nativos ao longo de um gradiente altitudinal (dos 10 aos 2200 m de altitude); (ii) quantificar a capacidade de 14 espécies, comuns da floresta nativa dos Açores, de reter água (interna- e externamente); e (iii) analisar in situ, durante 1 ano, o estado de hidratação das espécies selecionadas em 3 altitudes, na ilha Terceira. Uma metodologia padronizada (BRYOLAT) foi usada para determinar a distribuição de briófitos ao longo de um gradiente altitudinal (a cada 200 m) através de observações em plots de 100 m2. No total, 51 % (144) da riqueza de briófitos conhecida para a ilha foi alcançada. A distribuição, ao longo do gradiente altitudinal, apresentou um pico de riqueza aos 800 m (49 hepáticas e 23 musgos). Nesta faixa altitudinal são muito favoráveis as condições climáticas aumentando a complexidade da floresta (ótimos habitats para os briófitos). Novos locais foram registados para a ocorrência do musgo endémico raro Echinodium renauldii bem como um registo de uma espécie nova para os Açores, o musgo Antitrichia curtipendula (1600 m). A caracterização ecofisiológica envolveu seis hepáticas e oito musgos representando taxonomicamnente duas divisões e quatro classes. O conteúdo absoluto de água (AWC) foi determinado em ensaios experimentais através da saturação das amostras (peso saturado) e da sua completa desidratação (peso seco). A maioria das 14 espécies demonstraram preferencialmente um comportamento ectohídrico, mais de 60 % da água retida ocorre pela superfície da planta. A capacidade máxima de retenção de água variou de 646 % no Polytrichum commune, a 5584 % no Sphagnum subnitens. A perda de água por evaporação directa demonstrou, para a maioria das espécies, um declínio exponencial ao longo do tempo, onde no minuto 1 o máximo de água perdida foi exibido pela classe Bryopsida (espécie Thuidium tamariscinum: 12 %) e a taxa máxima de evaporação foi alcançada pela classe Sphagnopsida (0.84 g/min). O nível de hidratação das espécies em campo foi analisado através do FWC (conteúdo de água em campo) e do RWC (conteúdo de água relativo à capacidade máxima). Cinco réplicas por espécie foram colhidas no campo e medidas mensalmente ao longo de 4 estações. O FWC, nalgumas classes, aumentou com o gradiente altitudinal e sazonalmente nas estações mais húmidas (inverno e primavera). Perceber quanta água os briófitos nativos adquirem, retêm e libertam para os ecossistemas contribui para um melhor conhecimento da capacidade da vegetação nativa resistir a alterações, por exemplo climáticas, bem como os seus potenciais impactos sobre a disponibilidade e qualidade da água – importante serviço dos ecossistemas realizados pelas plantas.
- Bryophyte Diversity along an Elevational Gradient on Pico Island (Azores, Portugal)Publication . Coelho, Márcia Catarina Mendes; Gabriel, Rosalina; Hespanhol, Helena; Borges, Paulo A. V.; Ah-Peng, ClaudineThe study of elevational patterns is a valuable method for inferring the influence of the climate and other variables in the regional distributions of species. Bryophytes are ideal for revealing different environmental patterns in elevational studies, since they occur from sea level to above the tree line. Taking advantage of the long elevational transect of Pico Island and the use of standardized survey methods, our main aims were: (1) to identify and characterize the alpha and beta diversities of bryophytes across the full elevational gradient (12 sites of native vegetation, ranging from 10 to 2200 m above sea level [a.s.l.]); (2) to detect the ecological factors driving bryophyte composition; (3) to identify bryophytes’ substrate specificity; and (4) to check the presence of rare and endemic species. The identification of 878 microplots yielded 141 species (71 liverworts and 70 mosses), almost half of those known to occur on Pico Island. The bryophyte species richness followed a parabolic unimodal pattern with a mid-elevation peak, where the richest native forests occur. A canonical correspondence analysis (CCA) of the bryophyte composition and explanatory variables revealed the effect of the elevation, precipitation, disturbance, richness of vascular plants and bark pH in explaining bryophyte compositions at regional levels. Very few species of bryophytes showed substrate specificity. Pico Island’s elevational gradient could be an asset for studying long-term changes in bryophyte species composition and alpha diversity under global change.
- The MOVECLIM – AZORES project: Bryophytes from Pico Island (2012)Publication . Gabriel, Rosalina; Morgado, Leila N.; Coelho, Márcia C. M.; Aranda, Silvia C.; Henriques, Debora; Pereira, Fernando; Borges, Paulo A. V.; HESPANHOL, HELENA; Sergio, Cecilia; Ah-Peng, ClaudineABSTRACT: In September 2012, Pico Island was surveyed along an elevational transept starting on Manhenha, at 10 m a.s.l., and ending on the Pico Mountain caldera, at 2200 m a.s.l. to obtain a systematic inventory of the bryophytes living in natural environments. A total of twelve sites were examined, separated by 200 m elevation steps. At each site, two 10 m x 10 m plots were established within 10-15 m from each other, and within each plot, three 2 m x 2 m quadrats were randomly selected and thoroughly sampled for bryophytes using microplots of 10 cm x 5 cm, collected to paper bags. Six substrates were explored within each quadrat: rock, soil, humus, organic matter, tree bark and leaves/fronds; three replicates were made for each substrate, whenever available and colonized by bryophytes, totalling a maximum of 18 microplots per quadrat, 54 microplots per plot, 108 microplots per site and 1296 microplots on the 12 sites of Pico Island. It was possible to collect two thirds of the maximum expected number of microplots (N=878; 67,75%), resulting in 4896 specimens, the great majority of which (n=4869) were identified to the species/subspecies level. Overall, it was possible to identify 70 moss’ and 71 liverwort’ species and subspecies. The elevation levels both with a greater number of microplots and higher richness of species were those between 600-1000 m a.s.l., coinciding with the native forest plots. The study contributed to improve the knowledge of Azorean bryophyte diversity and distribution at both local and regional scales, including the recording of new taxa for Pico Island and the Azores.
- Seasonal Hydration Status of Common Bryophyte Species in Azorean Native VegetationPublication . Coelho, Márcia Catarina Mendes; Gabriel, Rosalina; Ah-Peng, ClaudineABSTRACT: Bryophytes play a crucial role in the ecosystem’s water compartment due to their unique ability to retain water. However, their role within temperate native ecosystems is mostly unknown. To address this knowledge gap, a study was conducted on Terceira Island (Azores), focusing on 14 bryophyte species found at different altitudes (40 m, 683 m, and 1012 m); five samples were collected monthly, per species and location, and their fresh, saturated, and dry weights were examined in the laboratory; four species were collected from more than one site. Generalized linear models (GLM) were used to assert the influence of climate factors (temperature, precipitation, and relative humidity) and environmental variables on two water indicators: field water content (FWC) and relative water content (RWC). None of the examined factors, per se, were able to explain all cases. Species appear to respond to climate according to a limiting factor effect: at lower elevations, precipitation was determinant, while at medium elevations, FWC was influenced by a combination of precipitation and relative humidity. At higher elevations, temperature was retained for seven of the nine studied species. The RWC values indicated that the 14 bryophyte species remained hydrated throughout the year but rarely reached their maximum water-holding capacity, even at the highest altitude. Understanding the mechanisms by which native bryophytes acquire, store, and release water is crucial for comprehending the resilience of native vegetation in the face of climate change. This knowledge can also enable the development of strategies to mitigate the effects of climate change and protect vital water resources.
- Characterizing and quantifying water content in 14 species of bryophytes present in azorean native vegetationPublication . Coelho, Márcia Catarina Mendes; Gabriel, Rosalina; Ah-Peng, ClaudineBryophytes are an important component of plant diversity, may be found from sea level to mountaintops, and are particularly conspicuous on the Azores islands. These plants rely on environmental water, which acquires intercepting rain and dew (liquid water) and uses fog (water vapor), and transports both externally, by capillary forces, and internally, in different cells (specialized or not). This study characterizes and quantifies the ability of six liverworts and eight mosses to retain water, through different pathways, and to lose water by evaporation. Twelve replicates of each species were collected in Azorean native vegetation during the summer of 2016. The absolute water content (AWC) was obtained through measurements of specimens saturated, without free water, and completely dry. Most of the 14-target species showed an ectohydric behavior pattern retaining more than 60% of water through gametophyte surface. The AWC value ranged from 646% in Polytrichum commune to 5584% in Sphagnum subnitens. The water loss by direct evaporation showed, for most of species, an exponential decay curve along time. Understanding how much native bryophytes, acquire, store, and release water into the system contributes not only to the knowledge of native vegetation resilience but also to potential impacts on the availability and quality of water—a major ecosystem service performed by bryophytes.