DOI: 10.5061/dryad.z8w9ghx8t
title: Data from: Changes in liana density over 30 years in a Bornean rain forest supports the escape hypothesis

description: In two permanent plots of lowland dipterocarp forest at Danum a liana
 census in 1988 was repeated in 2018 using the same method. Trees ≥ 30 cm
 gbh (girth at breast height) were recorded for number of lianas ≥ 2 cm gbh
 on their stems. The forest was evidently in a late stage of recovery from
 a large natural disturbance. Over the interval, mean number of lianas per
 tree decreased by 22 and 34 % in plots 1 and 2. By 2018 there were
 relatively more trees with few lianas and relatively fewer trees with many
 lianas than in 1988. The redistribution was strongest for overstorey trees
 of the Dipterocarpaceae (more with no lianas by 2018) and understorey
 trees of the Euphorbiaceae (many losing high loads in plot 2). 
 Proportion of trees with lianas rose overall by 3.5%.  Number of
 lianas per tree showed a quadratic relationship with tree size (ln[gbh]):
 maximal for large trees, fewer for smaller and very large trees. Tree
 survival and stem growth rate were significantly negatively related to
 number of lianas, after accounting for spatial autocorrelation. Monte
 Carlo random samples of half of trees in 1988 were compared with the other
 half of trees in 2018. Relative frequency distributions differed
 significantly over time, but dipterocarps and euphorbs varied noticeably
 in their liana dynamics between plots. Regressions achieved best
 significant fits when number of lianas was a function of date, ln(gbh) and
 ln(gbh)2, but differently in the plots reflecting complicated host-liana
 dynamics. Analysis of most abundant trees species, individually,
 highlighted a group of emergent dipterocarps with low liana counts
 decreasing with time. Building on an earlier hypothesis, these trees lose
 their lianas with branch shedding, as they move into, and emerge from, the
 main canopy. They escape from the parasite. The process may in part
 explain the uneven nature of the forest canopy at Danum. Change in liana
 density was contingent on forest history and site succession, and
 plot-level structure and dynamics. Liana promotion in intermittent dry
 periods was seemingly being offset by closing of the forest and continued
 dominance by the Dipterocarpaceae.
description: The main data file,
 ‘liana_census_data.csv’ contains the counts of lianas (≥ 2 cm
 <i>gbh</i>, or girth at breast height [1.3 m]), ‘nr_liana88’
 and ‘nr_liana18’, on trees of stem <i>gbh</i> ≥ 30 cm alive at
 the time of census 1 (1988; [1]) and 2 (2018). Where a tree
 <i>gbh</i> value is missing (indicated as ‘NA’), this means
 that either a tree of 1988 had died by 2018, or one of 2018 had not yet
 recruited by 1988. The data come from two main permanent dynamics plots at
 Danum, each 4 ha in area, coded 1 or 2 in ‘plot’, and referred to as MP1
 and MP2 in the paper. Tree <i>gbh</i>s (‘gbh88’, ‘gbh18’) are,
 in fact, those of the main plot tree censuses in 1986 [2] and 2015
 [unpubl. data, Newbery D. M. et al.]: any individuals dying 1986-88 or
 2015-18 were discounted, and any recruiting in these periods were also not
 considered, for the purposes of the two liana censuses. The file has 5173
 records. Each
 tree, referenced by its ‘tag’ number, had been identified, and its ‘code’
 is a concatenation of 4-digit genus and epithet abbreviations. Full
 species names for each code are given in ‘liana_census_dict.xls’.
  Likewise, ‘fam’ has the family abbreviations, found in full next to the
 species names. They follow the revised and updated nomenclature of 2015,
 retrospectively applied to the 1986 tree data. The three columns ‘x’, ‘y’,
 and ‘z’, are the plot-specific X- and Y-coordinates (plot dimensions: 100
 m E-W by 400 m S-N respectively) for the trees (in m), and the elevations
 of the ground surface (in m) at those locations, referenced to each plot’s
 SW corner[3]. References: [1] Campbell, E. J. F. &
 Newbery, D. M. 1993 Ecological relationships between lianas and trees in
 lowland rain forest in Sabah, East Malaysia. <i>Journal of Tropical
 Ecology</i> <b>9</b>, 469-490. [2] Newbery, D. M., Campbell, E.
 J. F., Lee, Y. F., Ridsdale, C. E. & Still, M. J. 1992 Primary
 lowland dipterocarp forest at Danum Valley, Sabah, Malaysia: structure,
 relative abundance and family composition. <i>Philos. Trans. R. Soc.
 Lond. Ser. B-Biol. Sci.</i> <b>335</b>,
 341-356. [3] Lingenfelder, M. &
 Newbery, D. M. 2009 On the detection of dynamic responses in a
 drought-perturbed tropical rainforest in Borneo. <i>Plant
 Ecology</i> <b>201</b>, 267-290.