Experiments

Experiment 314 - Plant water uptake along a diversity gradient: Evidence for complementarity in hydrological niches?

Niche complementarity is often used to explain positive biodiversity-productivity relationships,
yet interspecific differences in resource use are seldom measured in experimentally manipulated
plant communities. Here, we propose to evaluate hydrological niche space for common grassland
species growing across a diversity gradient at the Cedar Creek Biodiversity II experiment. We
will use the stable isotopic signature of plant and soil water to evaluate species-specific depth of
water use and to address the following questions: (1) Does increasing plant diversity impact
depth of water uptake and rates of water loss in common grassland species? (2) Does
hydrological niche complementarity or niche overlap occur at varying levels of plant diversity?
(3) Does the degree of niche complementarity and niche overlap among coexisting species vary
intra-annually with shifting environmental conditions (e.g. temperature, precipitation, vapor
pressure deficit)? This research will directly test if hydrological niche complementarity is
associated with plant biodiversity. Additionally, this project will evaluate whether niche
complementarity arises from inherent interspecific differences in hydrological niche space or
from plastic shifts in water uptake under varying levels of biodiversity. Ultimately, results from
the proposed study will add insight to the mechanisms driving the positive diversity-productivity
phenomenon and will also enhance our understanding of grassland ecohydrology.

Niche complementarity is often used to explain positive biodiversity-productivity relationships,
yet interspecific differences in resource use are seldom measured in experimentally manipulated
plant communities. Here, we propose to evaluate hydrological niche space for common grassland
species growing across a diversity gradient at the Cedar Creek Biodiversity II experiment. We
will use the stable isotopic signature of plant and soil water to evaluate species-specific depth of
water use and to address the following questions: (1) Does increasing plant diversity impact
depth of water uptake and rates of water loss in common grassland species? (2) Does
hydrological niche complementarity or niche overlap occur at varying levels of plant diversity?
(3) Does the degree of niche complementarity and niche overlap among coexisting species vary
intra-annually with shifting environmental conditions (e.g. temperature, precipitation, vapor
pressure deficit)? This research will directly test if hydrological niche complementarity is
associated with plant biodiversity. Additionally, this project will evaluate whether niche
complementarity arises from inherent interspecific differences in hydrological niche space or
from plastic shifts in water uptake under varying levels of biodiversity. Ultimately, results from
the proposed study will add insight to the mechanisms driving the positive diversity-productivity
phenomenon and will also enhance our understanding of grassland ecohydrology.

Methods for e314

Datasets