Paper · 2025 · Functional Ecology

Rooting for the little guy: Below‐ground traits predict juvenile grass demography in microsites

Sam J. Ahler; Julie E. Larson; Jordan Lee; et al.

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Open access · cc-by

Abstract

Abstract Plant functional traits can be a powerful tool for predicting species demography in response to variable environmental conditions. However, accurate predictions of juvenile plant response require ontogenetically relevant traits that capture the response to microsite variability. This is particularly important when considering drivers of seedling emergence, survival, growth and recruitment of species in the context of population persistence or community assembly. We tested the effect of two different microsites on juvenile demography for eight perennial grass species in a semi‐arid system in Colorado along the western edge of the Great Plains. We used seed and root functional traits across multiple life stages to predict these responses and identify mechanisms driving species' emergence, survival, growth and recruitment. Contrary to our expectations, we found that microsites with increased soil moisture (i.e. furrows) had a negative effect on grass emergence early in the season but no effect on recruitment at the end of the season. This was likely driven by the increased growth and survival of grass juveniles in furrows compared to grass juveniles on the surface (reduced soil moisture). We also found that species with more acquisitive roots—from more rapid root elongation—benefited from the increased soil moisture early in the season, but this benefit disappeared later in the season, speaking to the value of using life‐stage specific traits to predict early life‐stage transitions. Variation in microsites will impact juvenile perennial grass demography differently depending on species' traits across life stages. While species in this system typically experience wet to dry transitions across the growing season, furrows with increased soil moisture reduce the intensity of this dry down and may alter demographic responses depending on grass functional traits across ontogeny. We found grass species that are adapted to take advantage of resource pulses did best in furrows where moisture was greater, but that species adapted to conserve resources under stress had limited capacity to respond to these resource pulses. Read the free Plain Language Summary for this article on the Journal blog.

Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗

The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.

Claims 8

Intervention effectobservedoriginal resultnegativemeasured

Claim · model-written summary

Moister furrows reduced early-season grass emergence.

Taxon
grasse0
Treatment
furrowse0
Outcome
grass emergencee0
Direction
negative effecte0
Qualifier
early in the seasone0

Not reportedComparator

Verbatim

e0

“microsites with increased soil moisture (i.e. furrows) had a negative effect on grass emergence early in the season but no effect on recruitment at the end of the season.”

✓ located verbatim in the source · abstract, characters 885–1055 · show in text ↑
Intervention effectobservedoriginal resultno effectmeasured

Claim · model-written summary

Moister furrows did not change end-of-season recruitment.

Taxon
grasse0
Treatment
furrowse0
Outcome
recruitmente0
Direction
no effecte0
Qualifier
at the end of the seasone0

Not reportedComparator

Verbatim

e0

“microsites with increased soil moisture (i.e. furrows) had a negative effect on grass emergence early in the season but no effect on recruitment at the end of the season.”

✓ located verbatim in the source · abstract, characters 885–1055 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Grass juveniles grew more in furrows than on the surface.

Taxon
grasse0
Treatment
furrowse0
Outcome
growthe0
Direction
increasede0
Comparator
grass juveniles on the surfacee0

Verbatim

e0

“increased growth and survival of grass juveniles in furrows compared to grass juveniles on the surface (reduced soil moisture).”

✓ located verbatim in the source · abstract, characters 1086–1213 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Grass juveniles survived better in furrows than on the surface.

Taxon
grasse0
Treatment
furrowse0
Outcome
survivale0
Direction
increasede0
Comparator
grass juveniles on the surfacee0

Verbatim

e0

“increased growth and survival of grass juveniles in furrows compared to grass juveniles on the surface (reduced soil moisture).”

✓ located verbatim in the source · abstract, characters 1086–1213 · show in text ↑
Associationobservedoriginal resultpositivemeasured

Claim · model-written summary

Species with faster root elongation benefited from higher moisture early in the season.

Taxon
speciese0
Organ / stage
rootse0
Outcome
benefited from the increased soil moisturee0
Qualifier
early in the seasone0

Not reportedDirection

Verbatim

e0

“species with more acquisitive roots—from more rapid root elongation—benefited from the increased soil moisture early in the season”

✓ located verbatim in the source · abstract, characters 1233–1363 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

The early benefit of acquisitive roots disappeared later in the season.

Organ / stage
life‐stagee0
Outcome
this benefit disappearede0
Qualifier
later in the seasone0

Not reportedTaxonDirection

Verbatim

e0

“this benefit disappeared later in the season, speaking to the value of using life‐stage specific traits to predict early life‐stage transitions.”

✓ located verbatim in the source · abstract, characters 1369–1513 · show in text ↑
Associationobservedoriginal resultpositivemeasured

Claim · model-written summary

Species adapted to resource pulses performed best in wetter furrows.

Taxon
grass speciese0
Outcome
did beste0
Direction
beste0
Setting
furrowse0

Verbatim

e0

“grass species that are adapted to take advantage of resource pulses did best in furrows where moisture was greater”

✓ located verbatim in the source · abstract, characters 1921–2035 · show in text ↑
Associationobservedoriginal resultnegativemeasured

Claim · model-written summary

Species adapted to conserve resources had limited responses to resource pulses.

Taxon
speciese0
Treatment
resource pulsese0
Outcome
limited capacity to respond to these resource pulsese0
Qualifier
under stresse0

Not reportedDirection

Verbatim

e0

“species adapted to conserve resources under stress had limited capacity to respond to these resource pulses.”

✓ located verbatim in the source · abstract, characters 2046–2154 · show in text ↑