Abstract
ABSTRACT Most of the land surface of Melville Island, Australia's second largest island, is covered in Eucalyptus savanna. One exception is an area at Yapilika where a large tract of savanna is dominated by Acacia shrubs. An ordination analysis of 122 quadrats revealed that the boundary of Eucalyptus dominance did not correspond to a major change in floristic composition. Detailed transect studies at one site on the boundary showed that Eucalyptus trees were abruptly replaced by a band of Grevillea trees which gradually gave way to Acacia shrub dominance. There was a gradual change in the floristic composition of the savanna across the boundary. The distributional limit of Eucalyptus was found to be independent of any hydrological discontinuity. There was a slight decrease (<2.5 m) in altitude from Eucalyptus to Acacia savanna. The Acacia savanna soils were sandier and their surface soil had significantly lower concentrations of Ca and Mg and significantly greater concentration of Al compared with the Eucalyptus savanna soils. Eucalyptus seedlings planted in the three savanna communities were not found to be under drought stress (pre-dawn leaf xylem potentials of > – 0.9 MPa) during the dry season. Over a 12 month period Eucalyptus tetrodonta and E. miniata seedling growth was not significantly different on the Acacia or Eucalyptus savanna, although this result may be due to the counteracting effects of greater soil fertility and tree competition in the Eucalyptus savanna and lower soil fertility in the treeless, and hence competition-free, Acacia savanna. This hypothesis is supported by the significantly greater growth of Eucalyptus seedlings on fertilized Acacia savanna soils. The limited production, dispersal and establishment of Eucalyptus seeds and the greater frequency of fires in the Acacia savanna probably explains the abrupt limit to Eucalyptus dominance along the edaphic gradient.
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Claims 13
Claim · model-written summary
The Eucalyptus dominance boundary did not match a major floristic change.
- Taxon
- Eucalyptus
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Eucalyptuse0 - Outcome
- boundary of Eucalyptus dominancee0
- Comparator
- major change in floristic compositione0
Not reportedSettingDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“the boundary of Eucalyptus dominance did not correspond to a major change in floristic composition.”
Claim · model-written summary
Across the boundary Eucalyptus trees gave way abruptly to Grevillea and then gradually to Acacia shrubs.
- Taxon
- EucalyptusEucalyptuse0
- Outcome
- abruptly replaced by a band of Grevillea treese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Eucalyptus trees were abruptly replaced by a band of Grevillea trees which gradually gave way to Acacia shrub dominance.”
Claim · model-written summary
Savanna floristic composition changed gradually across the boundary.
- Taxon
- EucalyptusEucalyptust0
- Outcome
- gradual change in the floristic compositione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was a gradual change in the floristic composition of the savanna across the boundary.”
t0“Eucalyptus”
Claim · model-written summary
The Eucalyptus distribution limit was independent of hydrological discontinuity.
- Taxon
- EucalyptusEucalyptuse0
- Outcome
- distributional limite0
- Comparator
- hydrological discontinuitye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The distributional limit of Eucalyptus was found to be independent of any hydrological discontinuity.”
Claim · model-written summary
Altitude declined slightly from Eucalyptus to Acacia savanna.
- Taxon
- EucalyptusEucalyptuse0
- Outcome
- altitudee0
- Direction
- decreasee0
- Value
- <2.5 me0
- Comparator
- Acacia savannae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was a slight decrease (<2.5 m) in altitude from Eucalyptus to Acacia savanna.”
Claim · model-written summary
Acacia savanna soil was sandier than Eucalyptus savanna soil.
Not reportedTaxon
Verbatim
e0“The Acacia savanna soils were sandier and their surface soil had significantly lower concentrations of Ca and Mg and significantly greater concentration of Al compared with the Eucalyptus savanna soils.”
Claim · model-written summary
Acacia savanna surface soil had lower Ca and Mg concentrations than Eucalyptus savanna soil.
Not reportedTaxon
Verbatim
e0“The Acacia savanna soils were sandier and their surface soil had significantly lower concentrations of Ca and Mg and significantly greater concentration of Al compared with the Eucalyptus savanna soils.”
Claim · model-written summary
Acacia savanna surface soil had greater Al concentration than Eucalyptus savanna soil.
Not reportedTaxon
Verbatim
e0“significantly greater concentration of Al compared with the Eucalyptus savanna soils.”
Claim · model-written summary
Planted Eucalyptus seedlings were not drought stressed during the dry season; predawn xylem potentials exceeded – 0.9 MPa.
- Taxon
- EucalyptusEucalyptuse0
- Outcome
- pre-dawn leaf xylem potentialse0
- Value
- > – 0.9 MPae0
- Qualifier
- during the dry seasone0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Eucalyptus seedlings planted in the three savanna communities were not found to be under drought stress (pre-dawn leaf xylem potentials of > – 0.9 MPa) during the dry season.”
Claim · model-written summary
Growth of Eucalyptus tetrodonta seedlings did not differ significantly between Acacia and Eucalyptus savanna over 12 months.
- Taxon
- Eucalyptus tetrodonta
Eucalyptus tetrodontae0 - Outcome
- seedling growthe0
- Direction
- not significantly differente0
- Qualifier
- 12 month periode0
- Comparator
- Acacia or Eucalyptus savannae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Over a 12 month period Eucalyptus tetrodonta and E. miniata seedling growth was not significantly different on the Acacia or Eucalyptus savanna”
Claim · model-written summary
Growth of E. miniata seedlings did not differ significantly between Acacia and Eucalyptus savanna over 12 months.
- Taxon
- E. miniata
Eucalyptus miniatae0 - Outcome
- seedling growthe0
- Direction
- not significantly differente0
- Qualifier
- 12 month periode0
- Comparator
- Acacia or Eucalyptus savannae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Over a 12 month period Eucalyptus tetrodonta and E. miniata seedling growth was not significantly different on the Acacia or Eucalyptus savanna”
Claim · model-written summary
Fertilization significantly increased Eucalyptus seedling growth on Acacia savanna soil.
- Taxon
- EucalyptusEucalyptuse0
- Treatment
- fertilized Acacia savanna soilse0
- Outcome
- growthe0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significantly greater growth of Eucalyptus seedlings on fertilized Acacia savanna soils.”
Claim · model-written summary
The authors suggest seed limitation and more frequent fires in Acacia savanna explain the Eucalyptus boundary.
- Taxon
- EucalyptusEucalyptuse0
- Outcome
- abrupt limit to Eucalyptus dominancee0
- Qualifier
- limited production, dispersal and establishment of Eucalyptus seeds and the greater frequency of firese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The limited production, dispersal and establishment of Eucalyptus seeds and the greater frequency of fires in the Acacia savanna probably explains the abrupt limit to Eucalyptus dominance along the edaphic gradient.”
The same questions in other papers
fertilization · growth · EucalyptusPositive and negative results
15 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- positive
13 papers more in this group
See all 17 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.