DOI: 10.5061/dryad.qr2677n
title: Data from: Trait patterns of epiphytes compared to other plant life forms along a tropical elevation gradient

description: Compared to other plant life forms, epiphytes remain understudied.
 Understanding the responses of epiphytes to changing environmental
 conditions is necessary to predict changes in ecosystem functioning
 especially in subtropical and tropical regions. We investigated the
 functional traits of epiphytes along a large elevation gradient on Mount
 Kilimanjaro, Tanzania. We measured traits of co-occurring trees and
 terrestrial non-tree life forms, and compared changes in
 community-weighted means of traits (CWM) and trait spread, the range of
 observed trait values. We chose traits linked to growth and persistence:
 leaf area, specific leaf area, leaf dry matter content, stem specific
 density, plant height, leaf carbon, leaf nitrogen, and leaf phosphorus.
 For most traits, differences in community-weighted means between life
 forms exceeded differences within life forms along the elevation gradient.
 Many CWM showed linear changes with elevation, but no response and
 unimodal patterns were also frequent. This was best explained by
 temperature, or a combination of temperature with precipitation or
 humidity, indicating effects of these factors on the distribution of
 epiphytic and non-epiphytic species. Trait spread did not change with
 elevation in nearly half of the traits, but hump-shaped patterns were also
 common, probably a result of weaker environmental filtering in the
 gradient center. The magnitude of trait spread, i.e. the variability
 between species of the same life form within communities, was highest for
 terrestrial non-trees. Excluding ferns from the analyses lead to marked
 differences in trait patterns for epiphytes, as ferns made up 59 % of the
 epiphytic species, while playing a minor role in the other groups. The
 observed differences can be explained by a dichotomy in epiphytic life
 strategies, with tough-leaved xero-tolerant species on one side and
 succulent soft-leaved species on the other. However, the influence of
 phylogeny was lower than expected from the taxonomic composition of the
 three life form groups. Our results emphasize that environmental
 constraints act upon functional traits of epiphytes, trees and terrestrial
 non-trees. The differences in trait expressions, arguably adaptations of
 the different life forms, need to be taken into account in conservation
 contexts as well as when modeling the effects of global change on
 ecosystems.
description: species
 traitsThe functional traits of
 the species used in this study. Traits covered: Leaf area, Specific leaf
 area, Leaf dry matter content, Canopy height, Stem specific density, Leaf
 C, Leaf N, Leaf P. Units are given in the second sheet of the table. For
 methods, please refer to the original publication. This is the original
 version as used in the publication. The latest version is always in the
 TRY database (https://www.try-db.org).CWM and trait
 spreadCommunity-weighted
 means, trait spread, and fraction of total cover represented by the
 sampled species for trees, epiphytes, and terrestrial non-trees including
 and excluding ferns and fern allies. Units are given in the second sheet
 of the table.plot
 elevationElevation of the plots
 used in this study. Units are given in the second sheet of the table. For
 precipitation, mean temperature, and mean humidity, please refer to
 Mwangomo, E., Otte, I., Detsch, F., Nauss, T., Hemp, A. & Appelhans,
 T. (2014) Monthly and annual climate data averaged from 2011 to 2013 for
 79 research plots on the southern slopes of Mt. Kilimanjaro - V 1.0. pp.
 DOI: 10.5281/zenodo.11695.