Kevin Ray Wormington

The characteristics of six species of living hollow-bearing trees and their importance for arboreal marsupials in the dry sclerophyll forests of southeast Queensland, Australia

Six species of trees located in the dry sclerophyll forests of southeast Queensland were studied to ascertain which was most suitable to be retained as hollow-bearing trees for nesting and denning by arboreal marsupials. Generally for all tree species, the number of entrances to hollows was positively correlated with the diameter at breast height (DBH) and the growth stage, and entrance diameters also increased in trees with a larger DBH. However, there were differences between the species; Corymbia citriodora had few hollows until the individuals were very large while Eucalyptus crebra had low numbers of hollows throughout its entire size range. It was concluded that a mixture of tree species provided a range of hollow sizes and positions that would be suitable for nesting and denning by arboreal marsupials in those forests. There were large differences between tree species in the relationship between tree size and estimated age. Five of the tree species took between 186 and 230 years to begin to produce hollows while E. crebra took up to 324 years. This suggests that tree species other than E. crebra may be the most preferred for retention in areas where hollow-bearing tree densities are lower than the prescribed level. Other data also suggests there are likely to be enough trees in larger size classes that would begin to form hollows within the next 50 years to compensate for an expected loss of hollow-bearing stags during that same period. In terms of forest operation, the retention of six hollow-bearing trees/ha would represent an estimated loss of 7.3-15% wood production

Tree hollow development in wet and dry sclerophyll eucalypt forest in south-east Queensland, Australia

Summary Tree hollow development was studied in Eucalyptus pilularis (blackbutt) and Eucalyptus microcorys (tallowwood) in wet sclerophyll forests, and Eucalyptus signata (scribbly gum) in dry sclerophyll forest in south-east Queensland, Australia. In all three tree species hollow development appeared to be primarily initiated by fungal infection entering trees through dead branches and/or branch stubs rather than from fire scars. The process of hollow development appeared to commence when the trees were around 100 years old. The size and abundance of hollows increased with the size and age of the tree but there were apparent differences between species. Hollows were found in the majority (>50%) of E. pilularis trees above 100 cm dbh. By contrast most E. microcorys and E. signata larger than 80 cm dbh had hollows. There was a similar difference between species in the numbers of hollows present in trees of different size. E. pilularis trees 100–110 cm dbh had two hollows per tree but this number were presen...

Using Next-Generation Sequencing to Contrast the Diet and Explore Pest-Reduction Services of Sympatric Bird Species in Macadamia Orchards in Australia

Worldwide, avian communities inhabiting agro-ecosystems are threatened as a consequence of agricultural intensification. Unravelling their ecological role is essential to focus conservation efforts. Dietary analysis can elucidate bird-insect interactions and expose avian pest-reduction services, thus supporting avian conservation. In this study, we used next-generation sequencing to analyse the dietary arthropod contents of 11 sympatric bird species foraging in macadamia orchards in eastern Australia. Across all species and based on arthropod DNA sequence similarities ≥98% with records in the Barcode of Life Database, 257 operational taxonomy units were assigned to 8 orders, 40 families, 90 genera and 89 species. These taxa included 15 insect pests, 5 of which were macadamia pests. Among the latter group, Nezara viridula (Pentatomidae; green vegetable bug), considered a major pest, was present in 23% of all faecal samples collected. Results also showed that resource partitioning in this system is low, as most bird species shared large proportion of their diets by feeding primarily on lepidopteran, dipteran and arachnids. Dietary composition differed between some species, most likely because of differences in foraging behaviour. Overall, this study reached a level of taxonomic resolution never achieved before in the studied species, thus contributing to a significant improvement in the avian ecological knowledge. Our results showed that bird communities prey upon economically important pests in macadamia orchards. This study set a precedent by exploring avian pest-reduction services using next-generation sequencing, which could contribute to the conservation of avian communities and their natural habitats in agricultural systems.

Termite (Isoptera) diversity of riparian forests, adjacent woodlands and cleared pastures in tropical eastern Australia

The Fitzroy River (Central Queensland) has the second largest ocean‐flowing catchment in Australia and retains relatively extensive remnant woodlands. However, clearing of the more fertile alluvial plains is proportionally much greater. Typically, forested habitat on the alluvial plain is restricted to narrow riparian corridors and small remnants on the adjacent terraces. Riparian forests are known to be important repositories of biodiversity in cleared and uncleared landscapes. However, little is known about the invertebrates of these habitats. Termites are ecosystem engineers promoting soil health and organic decomposition, and keystone taxa by virtue of mound and nest construction, and the hollowing of living trees. A comparison of the termite fauna of riparian forests and vegetation of the adjacent terraces (either remnant woodlands or cleared for grass‐dominated pastures) was made at five locations in the Fitzroy River basin. Terrace pastures had fewer species than terrace woodlands while termite encounters within the riparian forests were lowest. Termite assemblages also differed between the three vegetation types. Some species showed zonation patterns. These patterns may relate to ecosystem drivers such as frequency of flooding in relation to life history parameters (e.g. arboreal or ground nesting). Termite species distribution also appeared to be coupled to resource availability such as presence of live and dead wood and percentage cover of litter, grass and dung. To retain natural levels of termite diversity and functionality, it is recommended that land managers retain both riparian forests and adjacent woodlands in a matrix with cleared pastures.

Eucalypt forests as indicators of the gradients within the central Queensland serpentine landscape of Australia

The eucalypt forests of the central Queensland serpentine landscape on the eastern coast of Australia are dominated by two overstorey species. These are Eucalyptus fibrosa F.Muell. subsp. fibrosa, the most dominant tree occurring throughout the landscape, and Corymbia xanthope A.R.Bean & Brooker, a serpentine endemic species which has a more restricted distribution. We hypothesised that the structure and foliage elements of the eucalypt forests could be used as biological indicators of the severity of the serpentine soils. This was tested by surveying 30 plots (50 × 20 m) within the upland landform patterns of the central Queensland serpentine landscape. The structure of the forests and abundance of the species were recorded and foliage samples from the dominant tree E. fibrosa subp. fibrosa were collected and analysed for metal and nutrient content. Soil samples from each site were collected and analysed for major cations, bio-available metals and fertility. Analysis of the data showed that there are significant correlations between the structure of the eucalypt forests and the landform patterns and soil chemistry. The relative basal area of C. xanthope is a useful measure of the severity of the serpentine soils and correlates to the soil Mg : Ca quotients. The tree E. fibrosa subsp. fibrosa was found to regulate its uptake of soil elements and cannot be used as an indicator of soil elements.

An ecological study of the central Queensland ultramafic endemic shrub Neoroepera buxifolia (Picrodendraceae), Australia

The ultramafic endemic shrub Neoroepera buxifolia Muell.Arg. & F.Muell (Picrodendraceae) has high habitat specificity and is mostly restricted to the perennial and ephemeral creeks and drainage lines of the central Queensland ultramafic landscape. It has an association with high magnesium (Mg) concentrations in the soil and the present study seeks to determine whether there is a correlation between populations of N. buxifolia and the soil extractable Mg and/or Mg : calcium (Ca) quotients in the soil. This was achieved by measuring the standing volume, height and seedling counts of N. buxifolia against the soil elements and other plot characteristics. Whereas correlations were found between increased height of N. buxifolia and the Mg : Ca quotients, soil extractable nickel (Ni) had the greatest influence. The standing volume of N. buxifolia also increased with soil extractable Ni. The standing volume of N. buxifolia was greatest in the upper tributaries of the first-order ephemeral creeks and presence of permanent water of the perennial creeks did not influence the standing volume or height of N. buxfolia.