Diversity patterns of epiphytic bryophytes across spatial scales: Species?rich crowns and beta?diverse trunks

Tropical forests are highly diverse at many spatial scales. In these forests, small-sized canopy organisms can form species-rich communities already within a few cm2. Understanding how species numbers increase when expanding the sampling along tree and forest is critical for evaluating processes maintaining biodiversity. We therefore studied epiphytic bryophyte diversity in crowns trunks across scales tropical lowland Amazonian Ecuador, bryophytes 100-cm2 quadrats on 24 trees (15–22 each) using spatially hierarchical design, analyzing alpha beta different grains extents. At smallest grain, held more than trunks, but largest grain most (93 vs. 77), as was higher among crowns. However, except extent (all trees), highest always found between trunks. Species turnover strongly dominated all This high richness resulted unpredictable compositions, especially trunk communities. These patterns suggest controls of an important role chance shaping The trees, combination with large effort involved climbing implies that small efficient intensive (many plots trees) rather extensive area) sampling. Abstract Spanish available online material. Los bosques tropicales son altamente diversos diferentes escalas espaciales. En estos bosques, pequeños organismos de dosel pueden formar comunidades ricas en especies incluso dentro unos pocos centímetros cuadrados. Comprender cómo incrementa el número al expandir muestreo árbol y bosque es crítico para evaluar los procesos que mantienen la biodiversidad. Por lo tanto, estudiamos diversidad briofitos epifitos las copas largo troncos través espaciales un tierras bajas amazonia ecuatoriana mediante con cuadrantes 100 cm2 árboles (con entre 15 22 por árbol), implementando diseño jerárquico espacio analizando alfa granos extensiones grano más fino, albergaron briofitas troncos, pero grueso, 77) dado fue mayor copas. Sin embargo, excepto extensión amplia (los árboles), consistentemente cuando se contrastaron coronas troncos. El recambio dominó todas Esto sumado alta riqueza resultó una composición impredecible, especialmente patrones observados sugieren controlan aleatorios juegan papel importante conformación estudiadas. La junto esfuerzo asociado trepa acceder implican muestrear puede ser eficiente manera intensiva muchos arboles), extensiva (muchos cuadrantes). Non-vascular epiphyte exhibit scale centimeters, while added adding branches or to regions continents (e.g., Draper et al., 2005; Medina 2010; Mota Oliveira & ter Steege, 2013). Processes controlling vary considerably such widely diverging (Medina Achieving multi-scale descriptions crucial guide tests models relative importance stochasticity, interactions, environmental filtering, dispersal limitations determining composition their assemblages. For plant communities, richness, “the natural measurement biodiversity” (McGill 2015), increases predictable manner known species-area relationship (SAR; Storch, 2016). describing other measure diversity, dissimilarity varies demands distinguishing resolution (i.e., grain: area each sampled unit) geographic (the covered by observations; Gonzalez 2020). Increasing extents fixed plot size) will result average units because samples located further apart likely differ them closer other, is, smaller (Barton turn, increasing decreasing units, larger contain thereby also shared bryophytes, has been suggested be lower hundreds km crown very same (Mota 2009). pattern suggests local (environmental constraints interactions; McGill 2015) meta-community (spatial heterogeneity limitations; structuring fine long-distance gradients limitations. due strong variation experienced vertical dimension habitat combined easy spores. driving may sections. To understand processes, accurate description both zones needed, several per zone—a practice unfortunately uncommon studies (Sanger Kirkpatrick, 2017; Zotz, 2007). topographically depend conditions. instance, cloud where moisture air drainage frequent fog occurrence, hold richer liverwort rain nearby slopes (Gehrig-Downie 2013; Gradstein, 2006). Effects topography thus relevant (sensu structured, we horizontal varying hyper-diverse surrounding Yasuní Scientific Station lowlands Ecuador (Bass 2010). Our research questions were follows: How distributed from bases canopy? do its components (turnover nestedness) extents? compare scales? More specifically, which does become single tree? (YSS), Orellana province (0°40?27?S 76°23?50?W, ~230 m a.s.l., ~90 ha) South Tiputini river (Figure 1a), part National Park Biosphere Reserve (190–400 2,366,182 ha; Estación Científica Yasuní, 2015). YSS holds terra-firme up 150 hectare Valencia 1994, 2004); rich palm liana species. modestly undulating terrain (Tschopp, 1953), valleys ridges less elevation, features poor clayey soils originated weathering dominant materials intersection two geological shields, Andes Brazilian (stratified clays sediments Curaray formation tertiary; Tschopp, 1953). region corresponds Holdridge Life Zone wet (Holdridge, 1947, 1964) experiences equatorial climate imperceptible seasonality (Bailey, 2014), annual mean temperature ~25°C, precipitation ~2240 mm/year 1b). applied study design survey stratified (valleys ridges) distance River (200, 500, 800, 6000 m). stratification anticipated toward moisture. four sites, six trees: three valley closest ridge 1c). Thus, encompassed five grains: entire set clusters ca. 200 cluster 1c); 90 1d); trees; quadrats. number varied 22, depending height first branch (see Section 2.2.1. Survey communities); used square thin branches, reduced diameter compelled us use rectangular 1e). selected mature excluding emergent subcanopy safe climbing. Tree DBH averaged ~60 cm, ~25 m, radius ~7 m. belonged 18 11 families (Table S1), so mostly singletons host preference epiphytes not analyzed. non-vascular established middle Johansson, 1974) gradient ground level living crown, adapted techniques (Perry, 1978). systematic regular intervals authors American (Gómez González Mellado-Mansilla Patiño 2009; Wolf, 1994). protocol consisted collecting randomly estimated cover (10 out 20 medium section one base branch). 240 collected layer (24 × 10 quadrats), 198 5 12 branch, 14 quadrat size allowed fix (10) regardless as, even there plenty opportunities reach locations suitable sample. Collected air-dried transported herbarium Pontificia Universidad Católica del Ecuador—QCA (Quito)—and cryptogamy collection Herbarium Muséum d'Histoire Naturelle—PC (Paris)—for identification. Mosses identified Churchill (1994), Buck (2003) Florschütz-de Waard al. (2011), liverworts Gradstein Ilkiu-borges (2009) manuscript version (2021). Predictors recorded level. descriptors valley/ridge position, (as categorical variable identifying 6-tree clusters), breast (DBH, cm), (m) (m), simple field (Zhu 2021) proxy size. effect could analyzed, represented only once our sample S1). Quadrat position (m). estimate cover, pictures taken mobile phone processed Gap Light Analyzer (GLA Version 2.0; Frazer 2008) openness, indicator light availability. describe distributes accounting possible influence additional predictors random factors, fit generalized linear (GLM) predicting quadrat, Poisson error distribution “log” link function, function zone (crown trunk—as provided parsimonious grouping Appendix S1 Supporting Information), DBH, height, variable), topography, interaction last two. effects zone. fitted best model Akaike information criterion, corrected (AICc). assessed overdispersion residuals calculating root quotient penalized residual sum squares observations, “dispersion_glmer” r package “blmeco” (Korner-Nievergelt 2015); value 0.978 ruled model. modeling approach performed R, fitting “glmer” “lme4” (Bates companion functions “lmerTest” (Kuznetsova 2017), “car” (Fox Weisberg, 2019), “MuMIn” (Barton, 2020) R packages. aggregated tested differences (tree, 3-tree cluster, paired t-tests. Based Mantel assessing independence S2), considered replicates independent testing zones. addition, Wilcoxon signed rank test raw data, those gathered partitioning developed Baselga (2010, 2017); Leprieur (2015); Orme (2012) framed respond space. discriminates nestedness pairwise comparisons units. evaluate calculated Sörensen dissimilarities components, nestedness, (species presence/absence) tree, summarized whole (trunk crown), compared means either ANOVA Kruskal–Wallis tests, data. analyses corresponding visualization (annotated heatmaps derived clustering classifications based Euclidean distances) built (Version 4.0.2) packages “betapart” (Baselga 2021), “ComplexHeatmap” (Gu (cf. Barton 2013), analyses: (a) assess extent, clusters, grain. (crowns trunks) t-tests, reference extent. (b) influences measurements, cluster. (c) sharing zones, percentage exclusive trunk, grains. this end, community respective group plotted changes percentages triangular (Koleff 2003). addressed specific sub-question what becomes tree. this, contrasted it against 95% confidence intervals. (n = 24). Then, crowns, grain) extents: 8), 4), 1). identify expressed geographical no correlation occurred matrices any S2); therefore, “mantel” (“vegan” package; Oksanen 2020), “beta. pair” (“betapart” “Ternary. Plot” (“Ternary”; Smith, “t.test” (“stat”, Core Team, 2658 occurrences 115 including new science records Ecuador. species, Lejeunea yasuniensis Gradst. C.Bastos (Gradstein, nine total Two (Lejeunea rionegrensis Spruce observed Xylolejeunea pellucidissima [Spruce] tree) (Acrolejeunea torulosa (Lehm. Lindenb.) Schiffn., Syrrhopodon simmondsii Steere, Thysananthus amazonicus (Spruce) Steph.). total, 72 34 genera, 43 moss 16 29 genera (Appendix S2). Cheilolejeunea rigidula Ceratolejeunea cornuta occurring 52% 51% quadrats, botanic family, Lejeuneaceae, richest 54 Singletons corresponded 21% 14% plots. double (8 ± 3 4 2 SD; Kruskal–Wallis: x2 166.85, p < 0.01). modulated (ACR) increased Table S3). Neither nor main influenced metric (Tables S3 S4). accumulation curves rarefaction extrapolation 2a), indicated strategy (intensive maximum km) captured regional pool well curve would require sizes ever saturate, consistent finer (sampling disappeared 2b). area, representing gamma harbored (93) (77) 2a,b). Using (0.70 0.02) did (0.69 0.03) (0.64 significantly (0.49 0.02; 0.01; Figure 3a). scales, consistently (values 0.4 0.8), low values around 0.1 (Figures 3b 4a), Sorensen Beta 4a). When (quadrats, clusters) decreased 4b). estimates differed Interestingly, lowest (~0.3) again ~0.4 broadest (6-tree clusters). Another now clear (from 22% 47%), crown-exclusive drops 20%) trunk-exclusive slightly 26% 34%; Figures (calculated tree), broader 6). comparing longer similarity course universal pairs 7a), compositional 7a, dendrogram top color bars indicating potential variables: valley, trunk) zonation stronger determinant proximity. levels aggregation (looking stems distinction (dendrograms 7b–d). landscape (ridge valley) (sites, i.e., groups appear have much mixing analysis 7, S4 S5). aggregation, increasingly similar (indicated lighter shading right (crowns) bottom left (trunks) quarters 7 (white ignored, self-dissimilarities, hence 0). Crowns if kilometers apart. Nearby own full were, average, dissimilar they Contrary expectation, play scale. recognized composition; patterns: scale, ability (Glime, Vanderpoorten, 2018; Pérez 2011), particular wind-exposed explain lack structure homogenization extremely overall, twice hardly forest. Across whether looking cm-scale apart, 10-km homogeneous however. Instead, over trees. Given complexity canopies latitudes just organisms, encourage comparative types organism groups, methods here should provide useful reference. Higher reported moist (Cornelissen 1989; Gehrig-Downie 2001; Mandl Sanger 1993, 1994; Zhao Because availability often understory, add empirical support positive species-energy (Wright, 1983). Additionally, probably importantly, continuous experience wind speeds layers, enhancing propagules. connectivity better allowing colonize filtering humidity drawn (Nakamura 2017) remains explicitly assessed. Including broad range (treelets, subcanopy, canopy, assessment. observation led decrease crown-exclus