DOI: 10.5061/dryad.k6djh9whb
title: Data from: Influence of Myrmecophytic Acacia drepanolobium on the composition and growth of surrounding herbaceous vegetation

description: Whistling thorn acacia (Acacia drepanolobium) forms monodominant stands in
 black cotton soils in East Africa arid highlands. The tree defends itself
 against large mammal herbivores with spinescence and symbiotic ants. While
 these defences have been extensively studied, little is known about the
 extent to which A. drepanolobium defence may benefit other plants growing
 in close association. We examined variation in herbaceous vegetation
 height, biomass, and composition between areas underneath A. drepanolobium
 canopies and the adjacent matrix in both fenced herbivore exclosures and
 unfenced areas. In unfenced areas, there was more tall herbaceous
 vegetation and biomass underneath tree canopies than away tree canopies,
 while these differences were not significant in fenced exclosures. Both
 height and biomass of understory vegetation were negatively correlated
 with A. drepanolobium canopy height. In the fenced herbivore exclosures,
 there was higher species diversity underneath trees than the surrounding
 matrix, but these differences were not apparent in the unfenced areas. The
 differences in herbaceous vegetation composition (Bray-Curtis
 dissimilarity index) between underneath tree and off tree locations were
 more pronounced in the unfenced areas than within the fenced herbivore
 exclosures. Our finding suggests that highly defended trees may moderate
 herbivore effects on herbaceous vegetation. To the extent that herbaceous
 vegetation underneath trees experiences protection from herbivory, such
 refugia microhabitats may serve as recolonization nucleus in attempts to
 restore chronically overgrazed systems.
description: # Data from: Influence of Myrmecophytic Acacia drepanolobium on the
 composition and growth of surrounding herbaceous vegetation Dataset DOI:
 [10.5061/dryad.k6djh9whb](10.5061/dryad.k6djh9whb) ## Description of the
 data and file structure This summary describes the dataset used for the
 paper tittled "*Influence of Myrmecophytic Acacia drepanolobium on
 the composition and growth of surrounding herbaceous vegetation*". 
 ### Files and variables #### File: grass_hieght_and_biomass.csv
 **Description:** Contains data on herbaceous vegetation height (table
 height) and biomass (dried weight from) clipped biomass at each sampling
 site ##### Variables * location: Fenced, unfenced * site: Open (away from
 tree canopies), short (underneath short trees), tall (underneath tall
 trees) * hlbranch: height (cm) of the lowest tree branch * grassheight:
 height (cm) of herbaceous vegetation  * grassdryweight : weight in grams
 of dried grass biomass clipped from each sampling point #### File:
 dissimilarity_index.csv **Description:** Bray-curtis dissimilality index
 among sampling sites  ##### Variables * site: a unique number describing
 each paired (within fenced and unfenced areas) sampling site * HTREAT:
 Feanced; unfenced * disIndex: Bray-curtis dissimilality index #### File:
 Pin_hit_data.csv **Description:** Data collected using-ten point pinframe
 to eatimate species composition and cover  ##### Variables * site: a
 unique descriptor combining information for each sampling site; e.g 
 open-1-unfenced describes the first sampling site located in an open space
 (away from tree canopies) and is within the unfenced area * The rest of
 the colums consists of pin hits for all the species (morphospecies)
 recorded. where a species could not be reliably identified, we assigned an
 arbitrary unique name  ## Code/software R package was used for analysis
 and the code is provided in Zenodo