Abstract
The last two decades have seen an increased awareness of fire’s importance in xeric southern Appalachian forest communities and an increase in its use as a management tool. In the last ten years, managers have also witnessed the invasion of Paulownia tomentosa (hereafter Paulownia) following some of these fires, and apparently as a consequence of the fires. If the pattern of Paulownia invasion is to be understood and the species targeted for control, it is essential to determine the variables that favor the spread of this exotic species into natural areas following fire and determine if it is impacting native communities or species. This work found that fire increases similarity between locations as measured by species composition and that the strength of this effect increases with fire severity. This is counter to Ryan’s Fire Severity Matrix which predicts that similarity will be negatively correlated with fire intensity. Although similarity between study sites increased after burning, each remained distinctive in ordination space and those differences increased over time as species reestablished themselves and environmental gradients shifted towards their pre-fire distributions in response to site-specific differences. This thesis also documents Paulownia seed dispersal up to 3.5 kilometers from mature individuals; distances which are orders of magnitude greater than those over which iv dispersal is generally measured. It also demonstrates that although Paulownia seeds may enter the seed-bank under appropriate conditions, they are killed by all but the least severe fires unless protected by burial. These buried seeds, even when only under 2cm of soil in the absence of litter, exhibit very limited germination. Together this demonstrates that invasion is controlled by the yearly seed rain rather than an accumulation of seeds within the seedbank. Habitat models document Paulownia’s range restriction over time as the initially prevalent high light and low competition conditions disappear with increasing native vegetation cover. Paulownia habitat is however maintained along cliff margins and narrow, shallow soiled benches suggesting that Paulownia will persist where these land forms are present. Although no significant correlation was found between Paulownia’s presence or cover and native species cover or diversity, this may not continue as Paulownia’s cover increases with stem maturity.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. 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 10
Claim · model-written summary
Fire increased similarity between locations in species composition.
- Taxon
- Paulownia tomentosa
Paulownia tomentosae0 - Treatment
- firee1
- Outcome
- similarity between locationse1
- Direction
- increasese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“invasion of Paulownia tomentosa (hereafter Paulownia)”
e1“This work found that fire increases similarity between locations as measured by species composition and that the strength of this effect increases with fire severity”
Claim · model-written summary
The strength of the fire effect on similarity increased with fire severity.
- Taxon
- Paulownia tomentosaPaulownia tomentosae0
- Treatment
- fire severitye1
- Outcome
- the strength of this effecte1
- Direction
- increasese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“invasion of Paulownia tomentosa (hereafter Paulownia)”
e1“This work found that fire increases similarity between locations as measured by species composition and that the strength of this effect increases with fire severity”
Claim · model-written summary
Differences between the study sites increased over time after burning, although similarity increased after burning.
- Taxon
- Paulownia tomentosaPaulownia tomentosae0
- Outcome
- those differencese2
- Direction
- increasede2
- Qualifier
- over timee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“invasion of Paulownia tomentosa (hereafter Paulownia)”
e2“Although similarity between study sites increased after burning, each remained distinctive in ordination space and those differences increased over time”
Claim · model-written summary
Paulownia seeds were dispersed up to 3.5 kilometers from mature individuals.
Verbatim
e3“This thesis also documents Paulownia seed dispersal up to 3.5 kilometers from mature individuals”
Claim · model-written summary
Paulownia seeds are killed by all but the least severe fires unless protected by burial.
Verbatim
e4“they are killed by all but the least severe fires unless protected by burial”
e5“It also demonstrates that although Paulownia seeds may enter the seed-bank under appropriate conditions”
Claim · model-written summary
Buried Paulownia seeds show very limited germination even under only 2 cm of soil without litter.
Verbatim
e0“invasion of Paulownia tomentosa (hereafter Paulownia)”
e6“These buried seeds, even when only under 2cm of soil in the absence of litter, exhibit very limited germination”
Claim · model-written summary
Invasion is controlled by the yearly seed rain rather than by seed accumulation in the seedbank.
Verbatim
e0“invasion of Paulownia tomentosa (hereafter Paulownia)”
e7“Together this demonstrates that invasion is controlled by the yearly seed rain rather than an accumulation of seeds within the seedbank”
Claim · model-written summary
Habitat models show Paulownia range restriction over time as high light and low competition conditions disappear with increasing native cover.
- Outcome
- range restriction over timee1
Verbatim
e1“Habitat models document Paulownia's range restriction over time as the initially prevalent high light and low competition conditions disappear with increasing native vegetation cover”
Claim · model-written summary
Paulownia habitat is maintained along cliff margins and narrow, shallow soiled benches.
Verbatim
e1“Paulownia habitat is however maintained along cliff margins and narrow, shallow soiled benches suggesting that Paulownia will persist where these land forms are present”
Claim · model-written summary
No significant correlation was found between Paulownia presence or cover and native species cover or diversity.
Verbatim
e1“Although no significant correlation was found between Paulownia's presence or cover and native species cover or diversity, this may not continue as Paulownia's cover increases with stem maturity”