Ground Layer Response to Disturbance in the Pine-Dominated Eastern Foothill Region of West-Central Alberta, Canada
Bibliographic record
Abstract
The canopy cover of the Pinus contorta forests of west-central Alberta, dictates colonization of the forest floor ground layer. This dynamic ground layer is a mosaic of feather mosses and reindeer lichens in a system driven by disturbance. In this project, anthropogenic was used to control canopy cover change and study its effects on the ground layer. Timber companies selectively mechanically thinned sections producing three experimental areas with uncut controls. Data were collected from 182, 6.5 m2 plots located in the four thinning areas. Six general areas of inquiry were posed around determining ground layer responses to canopy opening: 1) vegetation, 2) plant species richness, 3) plant abundance, 4) diaspore availability, 5) environmental limiting factors, 6) moss and lichen establishment. In 1997, three timber companies were involved in selective tree removal at three different stand percentages (20/40/60%), however, these were not consistent when measured in 2005. This variation in operational logging along with changes over the seven year time period, resulted in strong disparity for each of the thinning regimes. Percent canopy cover change for all thinned plots was ranked and three new groups created; least, moderate, most canopy change. These new groups formed the basis for the data presented in Chapter 3. The three thinning groups had little to no effect on species richness, but overall showed a small decrease from measurements taken pre-harvest. Numbers of locally rare species were similar to pre-harvest levels, but there were some gains and losses of species between pre-harvest and seven years post-harvest. In contrast to the lack of change in diversity, the abundance of dominant species and major vegetation components underwent dramatic changes. Dominant species of both vascular plants and bryophytes decreased with increasing canopy openness, with vascular plants being gradually affected while mosses were more affected at less intense canopy opening. Abundances of lichens showed no change. When measuring limiting factors (biotic and abiotic) for ground layer mosses and lichens, diaspores (spores and fragments) were plentiful in all stands, but differed in abundance at the micro-scale. The position of feather mosses and reindeer lichen in the forest floor mosaic appears to be due to an intermingling of environmental influences (at both the meso- and micro-scale). With less environmental constraints on lichens and the widespread availability of lichen fragments, lichens are more tolerant to the conditions evoked by thinning than are mosses. Mosses are more restricted by environmental conditions and have more constrained diaspore dispersal than lichens. Thus, mosses are more limited both by diaspore dispersal and by harsh environmental conditions in open canopy habitats. Whereas relative humidity (RH) did not differ at the stand level, moss dominated areas had higher RH no matter where they occurred, lichen-dominated areas did not--suggesting the moss occurrence is at least partially controlled by micro-scale level factors. Moss establishment is effected by the "ghosts" of past events and substrates. Mosses are widespread in formerly moss-dominated areas that contain organic substrates and high canopy cover. Lichen establishment is limited in previously moss-dominated areas. Species interactions weighed more heavily on moss establishment than on that of lichens. Therefore, the effects of canopy change on the ground layer are variable corresponding to moss decreases, but not lichens. Seven years post-harvest species diversity is unchanged, but vegetation, as a whole, has been affected.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".