The ecology of Andropogon gerardii in the Baldhead Hills, Manitoba
Bibliographic record
Abstract
The ecology of Andropogon gerardii(sensu /af.) in three representative stages of sand dune stabilization was studied in the Baldhead Hills of southwestern Manitoba, from 1983 to 1985.Plant community composition, assessed using relative cover and above-ground biomass, and environmental variables (soil texture, chemistry and moisture, soil and air temperatures, precipitation, wind and sand movements) were measured.ln each of the sites (Dune, lntermediate and Prairie) Andropogon gerardii (sensu /af.) density, phenology, morphology, above-ground biomass, biomass allocation, tissue nutrient content and reproduction (seed yield, size, numbers, condition and reproductive effort) were also measured.Winds above the threshold for sand movement (14 km hr-1), acting on a dry sand surface (with over 75o/o bare ground) resulted in unstable conditions on the Dunes.This, combined with the nutrient-deficient soils, temperature extremes and sporadic and variable moisture availability presented significant constraints to colonizing plants.The few species present showed adaptations to the rigours of the environment, which nevertheless resulted in low community biomass and sparse vegetation cover.Greater surface stability on the lntermediate and Prairie enabled more species to colonize, a more complex community structure, greater community biomass, more litter and less bare ground.Plants intolerant of burial (Selaginella densa, Cladonia spp.) were only found on stabilized Prairie.Andropogon gerardii(sensu /af.) per-formed better on the Dunes with higher total shoot density, numbers of reproductive shoots, total biomass, individual plant biomass and relative cover.lts proportion of the total community biomass was g5% on the Dunes compared with 29% on the Prairie.ln the spring Andropgon gerardii(sensu /af.) was slower to emerge on the Dunes but then developed more quickly, 10-14 days before lntermediate and Prairie plants.Dune plants were taller with a higher rate of stem elongation and greater biomass allocated to stems than lntermediate and Prairie plants.Biomass allocated to stems and inflorescences was allometrically related to plant size in all populations.Dune plant nutrient content exceeded that for Prairie plants for most elements, which were concentrated in the leaves.The concentration of K, Ca and Mg was high in stems, particularly in Dune plants.Andropogon gerardii(sensu lat.) on Dunes matured earlier than lntermediate and Prairie plants and had more seeds, higher seed yield, more ripe seed and larger seeds although variability was high in all populations for most measured traits.lmmature and aborted seeds accounted for over 80% loss in Dune and Prairie populations.But in some individuals over 80% of seeds were mature and in good condition.Problems with establishment notwithstanding, when favourable growing conditions permit, Andropogon gerardii(sensu lat.) may be able to access open sites and establish new individuals from seed.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".