Overcoming bias in ground-based surveys of hollow-bearing trees using double-sampling

Harper, M. J. K.; McCarthy, Michael A.; Ree, Rodney van der; Fox, Julian C.

doi:10.1016/j.foreco.2003.10.022

Cited by 49 publications

(74 citation statements)

References 22 publications

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“…We recorded the number and location of all known bobuck den-trees (identiWed by radio-tracking; see Martin 2006;Martin et al 2007a) and every other tree that we judged from the ground to potentially contain a hollow large enough to make a suitable bobuck den-site (termed "other hollow-bearing trees"). Although there are diYculties associated with establishing the occurrence of tree-hollows from the ground (Gibbons and Lindenmayer 2002;Harper et al 2004), our judgement was based on the large size and visibility of the openings of the hollows we have observed bobucks using. We recorded a series of variables for all known den-trees and other hollow-bearing trees including species, diameter at breast height (DBH) within nine size classes (30-40, 41-50, 51-60, 61-70, 71-80, 81-90, 91-100, 101-110 and >111 cm) and distance to the nearest silver wattle tree.…”

Section: Vegetation Surveysmentioning

confidence: 99%

Resource distribution influences mating system in the bobuck (Trichosurus cunninghami: Marsupialia)

Martin

2007

Oecologia

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Mammalian mating systems are thought to be shaped by the spatial distribution and abundance of key resources, which in turn influence the spacing behaviour of individuals. In particular, female home range size is predicted to reflect the availability of key resources. We documented the availability and distribution of food and shelter resources for two neighbouring populations of bobucks, or mountain brushtail possums, Trichosurus cunninghami, that were characterised by different mating systems: our "forest population" was socially monogamous, whereas the "roadside population" was polygynous. Both silver wattle, Acacia dealbata, the main food resource for bobucks, and den-trees, which provided shelter, occurred at significantly higher density at the roadside site. The pattern of distribution of these two resources also differed between the sites. Both food and den-trees were scattered evenly throughout the roadside habitat. In contrast, den-trees were located predominantly at one end of the forest site, while silver wattle trees were located at the other. There was no significant difference in the amount of silver wattle, or in the number of den-trees, located within the home ranges of individual females at the two sites. However, forest females had home ranges, on average, almost three times the size of those of roadside females. At the roadside site, the size of female home ranges varied inversely with the density of silver wattle, indicating that these females ranged over as large an area as necessary to gain access to sufficient silver wattle trees. There was no such relationship among forest females. These populations provide a clear example of resource distribution determining female home range size. This influenced the number of female home ranges a male's home range overlapped with, which in turn determined the mating system. Such clear links between resource availability and mating system have not previously been established in a marsupial.

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Section: Vegetation Surveysmentioning

confidence: 99%

Resource distribution influences mating system in the bobuck (Trichosurus cunninghami: Marsupialia)

Martin

2007

Oecologia

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“…However, this method does not provide accurate counts of hollow abundance (Healy et al, 1989;Harper et al, 2004). Viewing hollows from a distance can be difficult, especially under low light conditions, or when obscured by foliage.…”

Section: Introductionmentioning

confidence: 99%

“…Fire damage to the bark, sap stains or other marks can be mistakenly identified as being a hollow. In addition, most definitions of a hollow include a minimum depth (Whitford, 2002;Harper et al, 2004), which cannot be accurately determined from the ground. This means that not all cavities identified during ground-based surveys will meet the definition of being a true hollow.…”

Section: Introductionmentioning

confidence: 99%

“…Climbing trees to search for hollows, either with ropes or ladders, results in a large improvement in data quality, potentially providing accurate information on the occurrence and characteristics of hollows in a tree and the use of the tree by fauna (Haseler and Taylor, 1993;Harper et al, 2004;Martin et al, 2004). However, when using ladders only small trees or hollows lower down the tree can be examined (Martin et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…Unsuitable trees may be retained for animal habitat in production forests if hollow presence is overestimated. There have been some attempts to assess the accuracy of ground-based surveys (Healy et al, 1989;Whitford, 2002;Harper et al, 2004). This has been done by comparing the number of hollows seen during a ground-based survey and those recorded using an alternative method, such as tree-climbing.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Errors associated with two methods of assessing tree hollow occurrence and abundance in Eucalyptus obliqua forest, Tasmania

Koch

2008

Forest Ecology and Management

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Native bird breeding in a chronosequence of revegetated sites

2008

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Restoration of degraded landscapes through replantings of native vegetation has been proceeding in response to habitat loss and fragmentation and plummeting biodiversity. Little is known about whether the investments in ecological restoration have resulted in biodiversity benefits. We evaluated the potential of restored sites to support populations by assessing bird breeding activity. We surveyed 21 revegetated sites of various ages (9-111 years) in the box-ironbark region of Victoria, Australia. Sites differed in landscape context, patch features and in-site characteristics. The latter, including whether sites were grazed, amounts of fallen timber and numbers of remnant trees, were most important in affecting overall bird breeding activity. Patch-configuration (e.g., shape, area) was of secondary importance. Landscape context appeared to have little effect on bird breeding except for one species. While these results suggest that in-site habitat structure is the predominant driver, we caution against dismissing the importance of patch characteristics and landscape context for two reasons. First, the available sites covered a relatively small range of areas (<54 ha), and we could not provide a broad range of landscape-contextual contrasts given that we could only use existing plantings. Second, much of the breeding activity was by bird species known to be tolerant of smaller woodland areas or of the open countryside. We show that there is very little breeding activity in replantings by species that have declined dramatically in rank abundance between large 'reference' areas and fragmented landscapes. It seems likely that most replantings provide habitat configurations unsuited for dealing with declines of species most vulnerable to habitat loss and fragmentation.

show abstract

Overcoming bias in ground-based surveys of hollow-bearing trees using double-sampling

Cited by 49 publications

References 22 publications

Resource distribution influences mating system in the bobuck (Trichosurus cunninghami: Marsupialia)

Resource distribution influences mating system in the bobuck (Trichosurus cunninghami: Marsupialia)

Errors associated with two methods of assessing tree hollow occurrence and abundance in Eucalyptus obliqua forest, Tasmania

Native bird breeding in a chronosequence of revegetated sites

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