Could the Canopy Structure of Bryophytes Serve as an Indicator of Microbial Biodiversity? A Test for Testate Amoebae and Microcrustaceans from a Subtropical Cloud Forest in Dominican Republic

Abstract

The mechanisms that ultimately regulate the diversity of microbial eukaryotic communities in bryophyte ecosystems remain a contentious topic in microbial ecology. Although there is robust consensus that abiotic factors, such as water chemistry of the bryophyte and pH, explain a significant proportion of protist and microcrustacean diversity, there is no systematic assessment of the role of bryophyte habitat complexity on such prominent microbial groups. Water-holding capacity is correlated with bryophyte morphology and canopy structure. Similarly, canopy structure explains biodiversity dynamics of the macrobiota suggesting that canopy structure may also be a potential parameter for understanding microbial diversity. Canopy roughness of the dominant bryophyte species within the Bahoruco Cloud Forest, Cachote, Dominican Republic, concomitant with their associated diversity of testate amoebae and microcrustaceans was estimated to determine whether canopy structure could be added to the list of factors explaining microbial biodiversity in bryophytes. We hypothesized that smooth (with high moisture content) canopies will have higher species richness, density, and biomass of testate amoebae and higher richness and density of microcrustaceans than rough (desiccation-prone) canopies. For testate amoebae, we found 83 morphospecies with relative low abundances. Species richness and density differed among bryophytes with different bryophyte canopy structures and based on non-metric multidimensional scaling, canopy roughness explained 25% of the variation in species composition although not as predicted. Acroporium pungens (low roughness, LR) had the lowest species richness (2 ± 0.61 SD per gram dry weight bryophyte), and density (2.1 ± 0.61 SD individual per gram of dry weight bryophyte); whereas Thuidium urceolatum (high roughness) had the highest richness (24 ± 10.82 SD) and density (94 ± 64.30 SD). The fact that the bryophyte with the highest roughness had the highest levels of diversity for testate amoebae suggests that moisture levels at the level of the bryophyte canopy may not represent a biodiversity driver in a cloud forest with high relative humidity; however, high roughness could generate a dynamic and fluctuating moisture environment with concomitant alternating microbial communities. A total of 26 microcrustacean morphospecies were found across 11 bryophytes; however, no bryophyte canopy effect was detected on their richness and density. Microcrustacean mean density was low ranging from less than one individual per 50 cm2 of bryophyte in Leucobryum (LR) to a maximum of 6 ± 3.37 SD individuals/50 cm2 in Monoclea (LR). This lack of pattern suggests that possible explanatory variables may be related to larger scale processes than those examined in this study.

Morphogeometric Approaches to Non-vascular Plants

“…Surface roughness has traditionally been measured by contact surface probes ( Rice et al, 2001 ), but more efficient laser scanning methods ( Rice et al, 2005 ) and stereoscopic image analysis ( Krumnikl et al, 2010 ), drawing on analogies to LIDAR scanning of forests. Uptake of these methods in bryology has to date been limited (although see Acosta-Mercado et al, 2012 ), but their application, in conjunction with shoot- and leaf-scale architectural characterizations, shows great potential ( Rice and Cornelissen, 2014 ).…”

A reassessment of testate amoebae diversity in Tierra del Fuego peatlands: Implications for large scale inferences

“…To the contrary, designs covering only a few ecosystem times will miss a part of the will only be detected by sampling designs covering the present. To the contrary, designs covering only a few ecosystem times will miss a part of the that testate amoeba species richness at the will only be detected by sampling designs covering the diversity patterns below the landscape level are strongly regulated by environmental conditions that testate amoeba species richness at the diversity), suggesting that diversity patterns below the landscape level are strongly regulated by environmental conditions diversity), suggesting that diversity), suggesting that Moreover, testate amoebae richness differed between the three mosses associations, suggesting that the host moss have an influence on microbial communities as shown for rainforest mosses differing in architecture and likely hydrological dynamics (Acosta-Mercado et al, 2012). Although there are no studies to our knowledge dealing with associations of testate amoebae with different macrophytes, the mechanical conditions such as the physical support offered by the different mosses could affect the periphytic communities.…”

Freshwater microcrustaceans of Hispaniola: new records and potential as biological control agents

“…Consequently, this species has been recorded in several countries of Central and South America and the Caribbean (Collado et al, 1984;Kotov & Dumont, 2000;Elías-Gutiérrez et al, 2008;Elmoor Loureiro, 1997). Moreover, I. spinifer was collected from seven of the 18 Caribbean islands analysed, except in Hispaniola (Acosta-Mercado et al, 2012). Generally, members of this genus inhabit the benthonic part of water bodies as they collect small particles at the bottom sediments or from submerged plants (Fryer, 1974).…”

“…In Hispaniola, Perez-Gelabert (2020) provides the latest checklist for zooplankton, including 24 species of the suborder Cladocera (only 3 species of the family Daphniidae), 4 species of the order Calanoida, and 31 species of the order Cyclopoida. Nevertheless, it is expected that biodiversity is greater, as the previous studies were carried out only in coastal brackish lakes in Haiti (Collado et al, 1984), and in bryophytes (Acosta-Mercado et al, 2012).…”