@article{fdi:010054317,
  title = {{U}nexpected mechanisms sustain the stress gradient hypothesis in a tropical alpine environment},
  author = {{A}nthelme, {F}abien and {B}uendia, {B}. and {M}azoyer, {C}harlotte and {D}angles, {O}livier},
  editor = {},
  language = {{ENG}},
  abstract = {{Q}uestions: {D}oes facilitation among plants increase with elevation in a humid tropical alpine system in which climatic and ecological conditions differ from other alpine environments? {W}hatmechanisms are involved in the interactions? {L}ocation: {V}olcano {A}ntisana, {E}astern {C}ordillera of the {E}cuadorian {A}ndes ( 00 28' {S}, 78 09' {W}). {M}ethods: {W}e selected the cushion-forming {A}zorella aretioides as a potential nurse plant along an altitudinal gradient ( 4400, 4550 and 4700 m) in the high tropical {A}ndes. {W}e quantified its effects on other plants at species and community levels by comparing the product vegetation cover 9 number of individuals of every vascular species found inside and outside 265 cushions, using the relative interaction index. {W}e inferred potential mechanisms behind the interactions through analysis of microclimate, soil moisture and soil nutrient measurements inside and outside cushions. {R}esults: {P}redictions of the stress gradient hypothesis ( {SGH}) were corroborated at community level, with transition from competitive or neutral effects of {A}. aretioides at 4400 and 4550 m to facilitative effects at 4700 m. {S}trong speciesspecific effects were observed along the altitudinal gradient, with a substantial effect of local habitat disturbance on the outcome of plant-plant interactions. {S}urprisingly, cushions lowered air and soil temperatures and air humidity, which reduced at higher elevations. {F}acilitation appeared to be caused by higher soilmoisture and nutrient content beneath cushions. {C}onclusions: {O}ur data extend the framework of the {SGH} by corroborating it for the first time in a tropical alpine system. {H}owever, the mechanisms underlying plant-plant interactions differed fromthose generally reported fromalpine environments, with facilitation varying according to resource-mediated stress ( nutrients). {I}t remains to be tested whether this is specific to tropical alpine systems.},
  keywords = {{A}ndes ; {A}zorella aretioides ; {B}iogenic habitat ; {C}ompetition ; {C}ushion ; {E}cuador ; {F}acilitation ; {RII} ; {S}pecies-specific effects ; {EQUATEUR} ; {ANDES}},
  booktitle = {},
  journal = {{J}ournal of {V}egetation {S}cience},
  volume = {23},
  numero = {1},
  pages = {62--72},
  ISSN = {1100-9233},
  year = {2012},
  DOI = {10.1111/j.1654-1103.2011.01333.x},
  URL = {https://www.documentation.ird.fr/hor/fdi:010054317},
}