Herbert River Research Articles

The Herbert River, Queensland, Tropical Australia: Community Perception and River Management

There is a widespread perception amongst the community of Ingham and surrounding areas that the Herbert River in tropical Queensland has aggraded since the time of European settlement. Yet this perception is not supported by such evidence as historical accounts of the river and river trade, changes at the Ingham gauging station since 1940 and comparison of channel cross‐sections surveyed since 1968. No reason has been identified for this divergence, but experience elsewhere teaches us that ignoring local perception is likely to result in an incomplete understanding of environmental issues. Unless the challenge of reconciling popular perception and deductive interpretation of the evidence is met, the potential for conflict will remain. Community proposals for strategies will struggle for support from the ‘rationalists’ and the community will oppose ‘rational’ strategies if they are not seen to be addressing the ‘real’ problems.

Tropical wildlife corridors: use of linear rainforest remnants by arboreal mammals

In fragmented landscapes, linear forest remnants have the potential to provide habitat and movement corridors for wildlife. We used systematic spotlighting surveys to sample arboreal mammals in 36 linear rainforest remnants in tropical Queensland, Australia. The effects of corridor width, height, isolation, elevation, and floristic composition on mammals were assessed with multiple regression models. Six species were recorded during 108 surveys. The most vulnerable species, the lemuroid ringtail possum ( Hemibelideus lemuroides), was found only in remnants comprised of primary rainforest that were linked to large tracts of continuous forest. Two other species, the Herbert River ringtail possum ( Pseudochirulus herbertensis) and striped possum ( Dactylopsila trivirgata), also favored corridors that were linked to forest tracts or fragments, with the former favoring high-diversity forest (primary forest or mixed regrowth) over low-diversity ( Acacia) regrowth. Three other species, the coppery brushtail possum ( Trichosurus vulpecula), green ringtail possum ( Pseudochirops archeri), and Lumholtz's tree-kangaroo ( Dendrolagus lumholtzi), occurred in both isolated and non-isolated remnants and both primary forest and regrowth. Our findings suggest that linear forest remnants that are floristically diverse (not Acacia-dominated regrowth) and at least 30–40 m width can function as habitat and probably movement corridors for most arboreal mammals in this region. The lemuroid ringtail, however, apparently requires corridors of primary rainforest of at least 200 m in width. Because the lemuroid ringtail is highly vulnerable to forest fragmentation, faunal corridors in this region should be designed wherever possible to meet its ecological requirements.

Distribution of coastal freshwater wetlands and riparian forests in the Herbert River catchment and implications for management of catchments adjacent the Great Barrier Reef Marine Park

Because coral reefs are sensitive to land derived inputs of nutrient and sediment, there is concern worldwide for the effects of anthropogenic change in river catchments on reefs. Thirty-one river catchments drain directly into the waters of the Great Barrier Reef, NE Australia. This case study was undertaken on the floodplain of the Herbert River catchment in north Queensland, utilizing remote sensing and GIS to assess both spatial and temporal changes in freshwater wetlands and riparian forests. We demonstrate that there has been a very large reduction in the area of these ecosystems since European settlement in the mid nineteenth century, with an 80% decline in their extent since 1943. We provide a range of quantitative measures to show that the landscape diversity of these ecosystems has also declined. These changes are of importance in terms of regional, national and international trends. We argue that policy, planning and management reform is required if the remaining ecological, economic and social values of these systems and the adjacent Great Barrier Reef Marine Park are to be maintained.

Changes in soil physical properties after one pass of a sugarcane haulout unit

Summary. Field trials were established at different locations within the Herbert River area near Ingham in North Queensland to assess the ratooning ability and yield of sugarcane after a wet harvest. Treatments consisted of harvesting under dry conditions and then applying 50 mm of irrigation, followed by no traffic (control), traffic of a haulout unit directly over the harvested row (traffic treatment), and traffic as above with the application of further irrigation to maintain wet soil conditions (traffic + water treatment). Undisturbed soil cores were collected from the row before harvest and after treatment imposition to assess the change in soil physical properties due to traffic. Soil cone resistance was also measured. Soil physical properties changed significantly after traffic with increases in soil bulk density and soil cone resistance and decreases in saturated hydraulic conductivity. The greatest change occurred in the top 20 cm of the profile. Yield at one site was significantly reduced after traffic and the effect was enhanced in the presence of water after traffic. It is suggested that to maintain good soil conditions in the row all traffic should be restricted to the central part of the inter-row. One way to achieve this is to match crop row spacing with equipment track widths.

Phylogeography of the freshwater fish, Mogurnda adspersa, in streams of northeastern Queensland, Australia: evidence for altered drainage patterns.

A phylogeographic survey was used to elucidate the relative roles of historical processes and contemporary gene flow in structuring the genetic pattern observed with Mogurnda adspersa. This species of freshwater fish is found in the rivers and streams of the northeastern highlands of Queensland, Australia. Specifically, this project focused on populations in the Tully and Herbert Rivers in the Atherton Tablelands. Sequence analysis indicated that three distinct clades exist in the headwaters of the Tully River. The population sampled from one of the Tully River streams (Cheetah Creek) contained haplotypes that displayed approximately 3.4% sequence divergence from other haplotypes detected in this river. Furthermore, these haplotypes formed part of the clade which exists throughout not only the Herbert River but other surrounding drainages in the area. These results support the hypothesis that the current genetic structure is strongly affected by changes in drainage patterns due to geomorphological processes that occurred in the recent past.

Sources, sinks, and export of organic carbon through a tropical, semi‐enclosed delta (Hinchinbrook Channel, Australia)

A mass balance for organic carbon in Hinchinbrook Channel was constructed to identify major sources, sinks, and the magnitude of organic matter available for export to the adjacent coastal zone. Total organic carbon input from the Herbert River and from net production of mangroves, phytoplankton, seagrasses, and benthic microalgae is 8.94 ×109 M Corg yr−1 (moles organic carbon per year). Mangroves and river inputs are the largest carbon sources, accounting for 56% and 27% of the total annual input, respectively. Benthic respiration and burial in sediments are the major sinks, accounting for 46% and 41% respectively of total losses (3.09 ×109 M Corg yr−1). This mangrove‐dominated coastal ecosystem is net autotrophic, with 5.85×109 M Corg yr−1 (65% of total Corg input) available for export to the adjacent nearshore zone. Total export of organic carbon from the region (adding carbon export from Missionary Bay mangroves on the northern end of Hinchinbrook Island) amounts to 82,800 metric tons of organic carbon per year. These results confirm earlier evidence indicating that much of the particulate sediment carbon in the adjacent coastal zone is of mangrove origin. This mass balance, although preliminary, demonstrates the importance of Hinchinbrook Channel as a source of organic matter for the Great Barrier Reef lagoon.

Export of nutrients and suspended sediment during a cyclone-mediated flood event in the Herbert River catchment, Australia

Changes in the river chemistry of the Herbert River (northern Queensland) during a flood event that followed Cyclone Sadie in January 1994 are presented. Parallel data sets collected by AIMS and CSIRO were generally well correlated. Around the flood peak, concentrations of dissolved inorganic nutrients declined to a minimum, whereas particulate nutrient concentrations increased to a maximum (particulate nitrogen, 1200 µg N L-1; particulate phosphorus, 225 µg P L-1). Concentrations of dissolved organic nutrients varied erratically. Concentrations of silicate and potassium, pH and electrical conductivity varied inversely with discharge. Good correlations were observed between the concentrations of particulates and concurrent discharge, with differing relationships existing during the rising and falling stages of the flood. It is estimated that this flood event resulted in the export of at least 600 t of N, 65 t of P and 100000 t of suspended sediments over a period of six and a half days, with most transport (85%) occurring within the first two days. Particulate fractions of N (50%) and P (80%) constituted the bulk of the nutrient flux. This study illustrates the potential for high nutrient exports during brief flood events from intensively farmed agricultural land within tropical catchments.

Evaluating a Corporate Geographic Information System (GIS): A Case Study in a Coastal Rural Catchment

Effective planning in rural regions depends on the availability of an appropriate information base. The development of improved information bases can have a significant positive impact on planning activities. Geographic Information Systems (GIS) are powerful tools that have a demonstrated capability to facilitate improved decision-making. Implementation of GIS in rural catchments has been limited to a few relatively simple applications. The data, software and hardware costs and skills required in establishing effective GIS-based planning appear to have dissuaded investment on the part of individual potential stakeholders. This article describes an approach used to facilitate the development of a corporate GIS facility involving collaboration between industry, the community, government and research agencies in the Herbert River catchment of north Queensland. It details activities aimed at familiarising stakeholders with the basic concepts of GIS and helping them develop an understanding of their requirements and opportunities for the use of GIS. A cost-benefit analytical framework used to evaluate investment in the system is outlined and a method to evaluate non-quantifiable impacts of the project is introduced. In doing so, a strategic approach for evaluating GIS that is broadly applicable for use in other rural contexts is provided.

Genetic differentiation among populations of Caridinazebra (Decapoda: Atyidae) in tropical rainforest streams, northern Australia

1. Caridina zebra is a common atyid shrimp in some tropical rainforest streams in far north Queensland, Australia. Genetic variation at five allozyme loci was used to estimate the level of dispersal among populations of this species, within and between stream systems. Shrimps were sampled from nine streams in the Tully River catchment and two headwater streams in the adjacent Herbert River catchment in an area under consideration for extensive hydroelectric development.2. High levels of genetic differentiation were recorded among most populations which suggests that, like other fully aquatic species, movement is limited to a very small spatial scale.3. In the Tully catchment, populations of shrimp from streams with confluences at high altitude showed less genetic differentiation than those from streams which directly entered the lower river. Dispersal between the latter streams is clearly limited by the presence of large waterfalls and cascades.4. Adjacent stream populations were often highly differentiated, despite their close proximity, suggesting that overland dispersal is unlikely. However, populations of shrimp in the two streams in the Herbert catchment were strikingly similar in genetic structure to those in adjacent headwater streams of the Tully. Such similarity may reflect relatively recent changes in drainage patterns.

Simulation of the effects of trash and N fertilizer management on soil organic matter levels and yields of sugarcane

The practices of mechanical harvesting of sugarcane ( Saccharum offininarum L.), without prior burning, and retention of the residues as a surface mulch or ‘trash blanket’ were introduced in the Australian sugar industry during the 1980s, and more than a third of the crop is now managed in this way. Experimental data on the long-term effects of these practices on soil fertility and crop yield, and on their impact on the environment, are scarce, and difficult and costly to obtain. To address this problem, the CENTURY model was adapted to study the long-term effects of sugarcane trash management on soil organic matter (SOM) levels, N mineralization, nitrate leaching and crop yields with different fertilizer N inputs. Simulations were run using a 91 year weather record for unirrigated sugarcane grown on two soils in the Herbert River district of north Queensland. The model indicated that adoption of trash blanketing on old cultivated soil would lead to an increase of approximately 40% in SOM after 60–70 years and that about half of this increase would occur in the first 20 years. After about 20 years of trash blanketing, N fertilizer applications could be reduced by 40 kg N ha −1 without loss of yield in the first subsequent cycle of a plant crop and five ratoon crops. However, yield reductions of 10–15% in a few years with high rainfall reduced the long-term average yield by 1.5–2.2% during the 70 years after reducing N fertilizer applications. The model results also showed that reducing fertilizer application rate by 40 kg N ha −1 for the plant crop would reduce average annual nitrate leaching for the full crop cycle by 29% with little reduction in crop yield (< 2%). Nitrate leaching was sensitive to excessive N fertilizer, and was greater with trash blanketing than with trash burning because of less evaporation of soil water early in the growing season. For the same reason, simulated yields were higher in trash blanket systems than in burnt trash systems at all levels of fertilizer N.

The Effect of Two Agricultural Techniques on Populations of the Cane Field Rat (Rattus Sordidus) in Sugarcane Crops of North Queensland.

R. sordidus is a major pest in the sugarcane-growing areas of north Queensland; however, little is known about factors affecting populations. This study investigated the effect of a minimum-tillage practice (green-cane harvest and trash-blanketing) compared with the conventional practice (pre-harvest burn and intensive cultivation) on the dynamics of populations of R. sordidus in sugarcane crops of the Herbert River District, N. Queensland, from Nov. 1987 to Sep. 1988 (from planting to harvesting of crops). Populations of R. sordidus became established earlier in trash-blanketed crops, but breeding was reduced as a result of the suppression of summer grasses, identified as a favoured food source of R. sordidus during the breeding period (Jan.-May). Cover of summer grasses was high in conventional areas, and these areas supported populations characterized by a female-biased sex ratio, a high incidence of pregnancy, females in the most productive age-class, and low turnover rates, relative to populations in trash-blanketed areas. Damage to sugarcane increased once breeding had ceased and the diet of R. sordidus had changed from seed and non-cane vegetation to sugarcane. Damage was similar in trash-blanketed and conventional areas, probably as a result of dispersal of individuals from conventional areas into trash-blanketed areas following the breeding period. Implications for population and damage levels of R. sordidus on a regional scale are discussed.

Integrated Land Evaluation as an Aid to Land Use Planning in Northern Australia

Current methods of agricultural land evaluation in use in Australia suffer from a number of inherent deficiencies that limit their usefulness as a tool for land use planning. A framework is presented whereby both biophysical and economic factors affecting land use are included in the one assessment. The method integrates biophysical and economic data to produce estimates of crop yield, net returns to land physical land suitability using an expert system. These estimates can be readily computed, updated and extended to land managers. The method also aims to estimate the probability of achieving a given net return to land. The method was applied at two different scales (1:100 000 and 1:5000) for four different land uses in the Herbert River district of North Queensland. The results indicated that a quantitative measure of economic performance could be obtained for a very large number of spatially diverse mapping units for the range of land uses examined. The method provides the facility for objective comparison of mapping units both between and within land uses. The presence of an improved information base can have a positive impact on land use planning activities. Activities such as land use conflict resolution and industry planning can benefit from the provision of economic suitability data. Importantly, the additional data provide the planner or decision maker with an added degree of flexibility. As such, the integrated methodology provides a significant advance on the existing methodology.

The use of crop yield prediction as a tool for land evaluation studies in Northern Australia

Adequate prediction of crop yield is essential in quantitative land evaluation studies. The AUSCANE simulation model, local expert opinion and historical records were used to predict crop yield and ccs (a measure of sugar content in the cane stalk) for sugarcane production for land mapping units at two different scales of investigation in the Herbert River district of northern Australia. Simulations were undertaken for a period of 25 years. The model performed adequately on clay soil types; however, it generally overestimated yield and ccs values on sandy soil types and underestimated values on loamy soil types. Yield estimates were influenced by mean daily solar radiation and changes in the soil water balance. Results from the yield prediction process have played a significant role in the development of a tripartite system of land evaluation based on crop yield prediction, expert systems for biophysical and economic land suitability and risk analysis.

Comparative Responses of Five Arboreal Marsupials to Tropical Forest Fragmentation

I used data from 160 spotlighting censuses to compare responses of five species of arboreal marsupial folivores to fragmentation of tropical rainforests in NE Queensland, Australia. Data from 1,062 mammal detections in 1986–1987 revealed a strong gradient in extinction proneness. Most vulnerable were lemuroid ringtail possums ( Hemibelideus lemuroides ), which declined by >97% in abundance in forest fragments and secondary regrowth. Herbert River ringtail possums ( Pseudocheirus herbertensis ) and Lumholtz's tree-kangaroos ( Dendrolagus lumholtzi ) exhibited negative but intermediate responses to fragmentation, whereas coppery brushtail ( Trichosurus vulpecula ) and green ringtail ( P. archeri ) possums were least affected, relative to populations in unfragmented rainforest. A multiple-regression model incorporating log10 fragment area and two measures of fragment isolation explained 82% of the variation in arboreal species richness in 10 fragments ranging from 1.4 to 590 ha. “Corridors” of secondary vegetation helped ameliorate effects of fragmentation for some species. The most useful indicator of extinction proneness was the relative abundance of a species in forest regrowth, not its initial rarity in unfragmented rainforest. The ability of these folivores to use regrowth appeared to depend upon their denning requirements, diet, and degree of arboreality.

Dynamics, flushing and trapping in Hinchinbrook channel, a giant mangrove swamp, Australia

Hinchinbrook Channel is a 44-km long tidal channel connected at its northern and southern ends to the continental shelf of the Great Barrier Reef. The channel drains 164 km 2 of mangrove swamps. It also drains the Herbert River. The dynamics within the channel and the flushing of the fringing mangrove swamps were studied both in the field and using numerical models. The dominant currents are tidal semi-diurnal and are due to two nearly identical tidal waves entering the channel at its norhtern and southern openings and meeting in the middle. The mangrove swamps contribute significantly to the tidal dynamics. When the Herbert River discharge is small, net residual currents are negligible even in the presence of wind and the residence time of water is about 2 months. Flushing of the fringing mangrove swamps is largely controlled by the trapping effect in the mangrove swamps, and is slow with an e -fold residence time of about 54 days. On the northern end, the mangrove-fringed channel is wide and shallow, and a barotropic, coastal boundary layer is formed, due to shallow water effects and trapping in mangrove swamps. This results in a long-term (2 weeks) trapping of water along the mangrove-fringed coast in calm weather. Thus, coastal waters are continuously exchanged and mixed with mangrove swamp waters, but mixing between coastal and offshore waters is much slower.

Cytogenetics of the Herbert River ringtail possum, Pseudocheirus herbertensis (Diprotodonta: Pseudocheiridae): evidence for two species

The two Herbert River ringtail possum subspecies, Pseudocheirus herbertensis ssp. herbertensis and P. h. ssp. cinereus, have diploid chromosome numbers of 12 and 16, respectively. The sex chromosomes of both subspecies are exceptionally large, with the X and Y chromosomes being approximately 16 and 12% of the haploid autosomal complement, respectively. A sex chromosome bivalent cannot be identified during male meiosis and a sex vesicle is not present during pachytene. The two karyotypes are most likely related by two centric fusion events affecting the autosomal complement. We conclude that the X and Y chromosomes have been translocated onto homologous autosomes to give t(XA) t(YA) ♀ t(XA) t(XA) ♂. Our data also strongly support the separation of P. h. cinereus as a distinct species.Key words: karyotypes, sex chromosomes, speciation.

Variation in responses of arboreal marsupials to fragmentation of tropical rainforest in north eastern Australia

Relative population densities of five species of arboreal marsupial were examined in eleven patches of rainforest (2–74 ha) created by extensive clearing. Species diversity increased with area of patches ( p = 0·01), and all species were present in four or more patches. However, individual species responded differently to fragmentation and reduction of habitat. Relative densities of the coppery brushtail possum Trichosurus vulpecula johnstoni and green ringtail possum Pseudocheirus archeri were similar to those in adjacent continuous rainforest, suggesting that these species may persist in small patches of habitat. The Herbert River ringtail possum Pseudocheirus herbertensis and Lumholtz's tree kangaroo Dendrolagus lumholtzi were absent from five and six patches respectively, but were present in high densities in other patches, indicating that only some patches provide suitable habitat for these species. In comparison, the relative densities of the lemuroid ringtail possum Hemibelideus lemuroides in patches were lower than those in adjacent continuous rainforest, suggesting that no patches were suitable. The differential responses of species to fragmentation are interpreted with regard to variation in their habitat requirements, dispersal abilities and diet.

Rb-Sr study of some igneous rocks near Chillagoe and Herberton, Northeastern Queensland

Abstract Sr isotope ratios indicate that the Herbert River and Elizabeth Creek Granites at the northeastern margin of the Georgetown Inlier of northeast Queensland are closely related to each other and to the spatially-associated Featherbed Volcanics. Although there is field evidence for a range of granite ages, the isotopic evidence is that a large proportion of the granite was formed within the Late Carboniferous (328 ± 5 m.y.). The Featherbed Volcanics are about 30 m.y. younger, at 299 ± 13 m.y. These are post-dated by other granites of the region.

The emplacement of acid magma in the epizone, and the relationship with ignimbrites, in North Queensland, Australia

There is an aggregate outcrop of 12,000 square miles of Permian-Triassic acid igneous rocks inland from Cairns and Townsville, North Queensland. The rocks consist of ignimbrite and rhyolite, which are structurally and magmatically related to three high-level intrusions the Herbert River, Esmeralda, and Elizabeth Creek Granites. Most of the igneous rocks intrude the Precambrian Georgetown Inlier, but some of them intrude along a fractured zone on the junction of the Inlier and the shelf zone of the adjacent Palaeozoic Tasman Geosyncline.

Birds of Cardwell and Herbert River Districts (N.Q.)

Birds of Cardwell and Herbert River Districts (N.Q.)