Canopy leaf area index at its higher end: dissection of structural controls from leaf to canopy scales in bryophytes

Abstract

Summary There is evidence that mosses with miniature foliage elements have extremely large leaf area index (LAI) values, but it is unclear what canopy traits are responsible for these high LAI values in architecturally divergent mosses, and how the inherent trade‐offs limiting maximum LAI in vascular plants can be overcome in mosses. To determine the quantitative significance of different traits in determining LAI, we developed a method to dissect LAI into underlying functionally dependent constituent traits at leaf, shoot and canopy scales. The suites of structural traits were studied altogether for 43 moss canopies from 11 species with contrasting light and water requirements along gap‐understory gradients to obtain as large a range of variation in moss architecture as possible and evaluate the differentiation in moss LAI in relation to species ecology. Extensive variation in moss structural traits, 11‐ (shoot length) to 77‐fold (shoot number per area, NnormalS¯), was observed at all structural scales from leaf to canopy. However, LAI only varied nine‐fold, as the result of two key trade‐offs: leaf size vs number trade‐off and shoot leaf area vs shoot density trade‐off. Owing to these negative relationships, and greater variability in NnormalS¯, LAI primarily scaled with NnormalS¯. NnormalS¯ and LAI increased with site light availability, and LAI was greater in open and dry habitat species. This study highlights a huge structural diversity among moss canopies, but indicates that canopies converge to a much narrower range of LAI due to trait trade‐offs such that, counterintuitively, minute leaf size and densely leafed stems are not necessarily responsible for high LAI in mosses.

Water’s path from moss to soil: A multi-methodological study on water absorption and evaporation of soil-moss combinations

“…To determine the surface areas of the studied moss species, we measured the following structural traits: leaf area, leaf frequency, shoot length, length of a single component (sum of shoot length and length of attached branches), shoot density (Table 3). We determined the surface areas of the studied species using the following formula, which we adapted for our experiment following Simon (1987), Niinemets and Tobias (2014) and Niinemets and Tobias (2019):…”

The moss traits that rule cyanobacterial colonization

“…Cyanobacterial abundance, on the other hand, is affected by different factors, such as the capability to move or disperse, and the environmental factors affecting these processes ( Solheim and Zielke, 2002 ). Among these factors, traits of the moss host, which provide microsites for epiphytic cyanobacteria ( Dalton and Chatfield, 1985 ), might play a key role as moss traits vary greatly among species ( Niinemets and Tobias, 2019 ), and certain moss species seem to be especially colonized by cyanobacteria ( Solheim et al ., 1996 ). However, to date, it remains unknown whether moss traits affect the colonization of cyanobacteria and, if so, which suite of moss traits facilitates cyanobacterial colonization that leads to differences between moss hosts.…”

A combination of morphological and photosynthetic functional traits maintains the vertical distribution of bryophytes in a subtropical cloud forest

“…Anatomical characteristics, such as thick cell walls, are positively associated with desiccation tolerance and nonstomatal diffusion conductance, resulting in lower photosynthetic rates (León, ; Carriquí et al., ). Thus, variation in morphological traits across different light environments is expected to link with trade‐offs between enhancing light interception and reducing water loss (Niinemets and Tobias, ).…”