Nutrient and nitrogen isotope monitoring of an aquaculture fishery in North Queensland, Australia

A one-time monitoring event was initiated by an aquaculture fishery in North Queensland to assess if the discharges from the aquaculture fishery were increasing nutrient input into the Great Barrier Reef Marine Park. Leaf samples from Avicennia marina (grey mangrove) were used to compare the nitrogen (N) and phosphorous (P) concentrations, and δ 15N values in the receiving waters of the adjacent creeks and a set of reference sites established in a neighbouring creek. The same indicators were also measured in macroalgae from the nutrient extraction ponds. The mangrove leaves in the Mixing Zone of the receiving creek were slightly elevated in N concentrations (22 mg g -1 compared to 17.5 mg g -1 at the Reference sites) and δ 15N values (6.5 compared to 4.5 at the Reference sites) showing there was an influence from the outputs of the aquaculture fishery. However, P concentrations were the same in the Mixing Zone and Reference sites. Downstream of the Mixing Zone, the concentration of N and P, and the δ 15N values in the Receiving Waters were the same as the Reference sites, at levels considered normal in other studies. These results show that aquaculture fisheries can be managed to maintain nutrients at reference levels in mangrove foliage in estuaries of the receiving zones

Mammal and reptile survey of Splitters Creek, near Bundaberg, Queensland : a report to Bundaberg & District Urban Landcare Assoc. Inc.

Survey aims to determine the "richness, abundance and habitat preferences of mammal and reptile species in various habitats at Splitters Creek near Bundaberg"--Abstract

Identifying essential ecological factors underpinning the development of a conservation plan for the endangered Australian tree Alectryon ramiflorus

Reintroduction of rare and threatened species often fails to yield quantifiable conservation benefits because insufficient attention is focused on the species' habitat requirements and biology. We demonstrate the value of such data in informing a recovery plan for Alectryon ramiflorus S.Reyn. (Sapindaceae), a tree species endemic to a region on the southern coast of Queensland, Australia. When the species was categorized as Endangered on the IUCN Red List in 1997 the total known population consisted of only 26 adult plants, in five disjunct populations in remnant patches of native vegetation. Analysis of vegetation type, soil chemistry and composition data comparing remnant patches with and without A. ramiflorus revealed that the species is not restricted to a specific soil type but prefers sites with relatively fertile soil and a more complex vegetation structure. The species is cryptically dioecious, displays asynchronous flowering between individuals, and requires insect-vectored pollination. The low rate of seedling production recorded within individual patches was attributed to the scarcity of trees of both genders, asynchronous flowering of individual trees and, in smaller patches, a sparse population of pollinating insect species. Successful reintroduction of A. ramiflorus will require consideration of these aspects of demographic success. The findings highlight the importance to species recovery plans of the knowledge of habitat requirements, interspecific relationships and critical dependencies, as well as species reproductive biology

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

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

Birds and bats as biological control agents in macadamia: How distant we are? Implications of the shift in arthropod communities across a spatial gradient

Agriculture affects and depends on all other life support systems. It is becoming essential to achieve the global food demand without compromising ecological integrity. However, little is known about important ecological interactions in agroecosystems. Such systems represent particular reserves for biodiversity with associated ecosystem services. One of the key ecosystem services in agriculture is the top-down control of crop pests exerted by predators. A large number of insectivorous bird and bat species have been found to efficiently decrease pest pressure in several crops worldwide. Scarce information is found on how the distance from forested areas impacts such ecosystem services. To our knowledge, no information is available for macadamia crops. Our study is the first of a series that attempt to explore the potential of regional bird and bat species as biological control agents in macadamia. The results describe the arthropod communities in these systems across a spatial gradient between the forest and the orchard. The study was conducted in 31 sites around Bundaberg (Australia). Arthropods were collected in macadamia orchards using sweep-net and light-traps at fixed distances from forest patches at each site. Results showed that the abundance and richness of arthropods decreased in points further away from forests. Points closer to forested areas had more balanced communities with higher percentages of predators and parasitoids and lower percentages of herbivores than points further away. Further research is being conducted to understand whether differences in spatial composition of arthropod communities are associated with the foraging activity of birds and microbats. An opportunity exists to integrate wildlife in macadamia production, and to benefit both the farmers and the environment

The State of Port Curtis Conference

The State of Port Curtis Conferenc

The status of hollow-bearing trees required for the conservation of arboreal marsupials in the dry sclerophyll forests of south-east Queensland, Australia

At 38 sites in the dry sclerophyll forests of south-east Queensland, Australia, hollow-bearing trees were studied to determine the effects of past forestry practices on their density, size and spatial distribution. The density of hollow-bearing trees was reduced at sites that had been altered by poisoning and ringbarking of unmerchantable trees. This was especially the case for living hollow-bearing trees that were now at densities too low to support the full range of arboreal marsupials. Although there are presently enough hollow-bearing stags (i.e., dead hollow-bearing trees) to provide additional denning and nesting opportunities, the standing life of these hollow-bearing stags is lower than the living counterparts which means dennning and nesting sites may be limited in the near future. The mean diameter at breast height (DBH) of hollow-bearing stags was significantly less than that of living hollow-bearing trees. This indicated that many large hollow-bearing stags may have a shorter standing life than smaller hollow-bearing stags. Hollow-bearing trees appear to be randomly distributed throughout the forest in both silviculturally treated and untreated areas. This finding is at odds with the suggestion by some forest manageres that hollow-bearing trees should have a clumped distribution in dry sclerophyll forests of south-east Queensland

Stuart Oil Shale Project terrestrial flora and fauna studies. Report 16, Biological monitoring of aquatic environments winter 2002 survey to Southern Pacific Petroleum (Development) [cover indicates report 18]

Report presents results for the winter 2002 survey of aquatic flora and fauna within the Gladstone Mt Larcom region as part of the ongoing biological monitoring for the Stuart Oil Shale Project near Targinie. In rder to relate this survey to previous monitoring events, this report also presents data from all seven surveys previously conducted, including from spring 1997 to winter 2001

Leaf nutrient concentrations and timber productivity in the dry sclerophyll forests of south-east Queensland, Australia : implications for arboreal marsupials

The species richness and abundance of arboreal marsupials are positively related to the proportion of total stand basal area occupied by Corymbia citriodora ssp. variegata and tree height in south-east Queensland, and have been related to nutrient availability and productivity in other parts of Australia. The objectives of this study were to assess the relationships of stand basal area occupied by C. citriodora and tree height, and the available nutrients and productivity in the dry sclerophyll forests of south-east Queensland. Leaf nutrient analysis of seven species of trees in south-east Queensland showed that the percentage by weight of phosphorus in leaves increased with the proportion of the total stand basal area of C. citriodora. This rate of increase was greater for C. citriodora than other species, indicating that C. citriodora may be more competitive on soils with greater available hosphorus. Corymbia citriodora leaves also contained higher concentrations of nitrogen and potassium than the other tree species on multi-species sites. Timber productivity was greater at the sites where trees were taller, and tree height was positively correlated to the proportion of total stand basal area of C. citriodora and rainfall, but was negatively correlated to the slope. These findings indicate that the most utilized habitat by arboreal marsupials in the dry sclerophyll forests of south-east Queensland, (i.e. taller forests with a high proportion of the stand basal area occupied by C. citriodora), had higher concentrations of foliar nutrients and were more productive than less utilized habitats