H. Finn

Why does experimentation matter in teaching ecology

The inquiry-based approach is an important component of secondary school biology curricula. However, we found that common Australian texts included little coverage of controlled experimentation in ecological practical work. The logistical and ethical difficulties in designing suitable ecological practicals may be a factor in these observations, as well as a perception that investigations of the complex interrelationships in ecology require scientific approaches other than experimentation. We argue that because controlled experiments are used extensively by professional ecologists to solve both theoretical and applied problems, experimentation should be a key component of secondary school ecology curricula. We suggest five teaching principles to guide secondary school biology teachers in providing a more realistic view of the possibilities and limitations of ecological experimentation. We also review ways in which computer simulations and microcosm experiments can be used to overcome logistical and ethical problems and allow students to design and implement ecological experiments. Whether based in the classroom or the field, the use of experimental approaches in secondary school ecology curricula illustrates ecological concepts, reinforces principles of experimental design and highlights the value of the inquiry-based approach in biological education.

Cetacean Morbillivirus in Coastal Indo-Pacific Bottlenose Dolphins, Western Australia

Cetacean morbillivirus (CeMV) has caused several epizootics in multiple species of cetaceans globally and is an emerging disease among cetaceans in Australia. We detected CeMV in 2 stranded coastal Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Western Australia. Preliminary phylogenetic data suggest that this virus variant is divergent from known strains.

Pine as Fast Food: Foraging Ecology of an Endangered Cockatoo in a Forestry Landscape

Pine plantations near Perth, Western Australia have provided an important food source for endangered Carnaby’s Cockatoos (Calyptorhynchus latirostris) since the 1940s. Plans to harvest these plantations without re-planting will remove this food source by 2031 or earlier. To assess the impact of pine removal, we studied the ecological association between Carnaby’s Cockatoos and pine using behavioural, nutritional, and phenological data. Pine plantations provided high densities of seed (158 025 seeds ha−1) over a large area (c. 15 000 ha). Carnaby’s Cockatoos fed throughout these plantations and removed almost the entire annual crop of pine cones. Peak cockatoo abundance coincided with pine seed maturation. Pine seed had energy and protein contents equivalent to native food sources and, critically, is available in summer when breeding pairs have young offspring to feed. This strong and enduring ecological association clearly suggests that removing pine will have a significant impact on this endangered species unless restoration strategies, to establish alternative food sources, are implemented.

Reduced Detection of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) in an Inner Harbour Channel During Pile Driving Activities

There is limited information on the impacts of anthropogenic noise on dolphin behaviour, making assessment and mitigation of impacts from anthropogenic noises difficult. As the use of echolocation and other vocalizations are of vital importance for cetaceans, it is important to better understand the potential impact of anthropogenic acoustic disturbance. The small Indo-Pacific bottlenose dolphin (Tursiops aduncus) community that inhabits the Fremantle Inner Harbour regularly travels through an area where impact and vibratory pile driving occurred during wharf upgrading. The overall aim of this study was to measure the noise energy created by pile driving associated with wharf construction activities in the Fremantle Inner Harbour and to determine whether the reduced detection of dolphins within the vicinity of the wharf was associated with pile driving activities. Measuring noise was accomplished with noise loggers and a hand-held digital acoustic recorder, under water, allowing identification of signals produced by impact and vibratory pile drivers and calculating the energy of recorded noise. Dolphin detections in the Inner Harbour were conducted by examination of high-definition video recordings. The association of pile driving and dolphin detections was assessed using Generalized Estimating Equations (GEEs), using observations before and during pile driving. The final model indicated that there was a difference in detections between the two treatments, with more dolphin detections observed when there was no pile driving activity taking place (mean = 0.26 +/- 0.03 SE) than during pile driving (mean = 0.18 +/- 0.04 SE). Knowledge generated by this study on the impact of noise on bottlenose dolphins improves the scientific basis for managing

Feeding activity of threatened black cockatoos in mine-site rehabilitation in the jarrah forest of south-western Australia

Abstract. Land clearing threatens three black cockatoo species (forest red-tailed black cockatoo, (Calyptorhynchus banksii naso), Carnaby’s cockatoo (Calyptorhynchus latirostris), and Baudin’s cockatoo (Calyptorhynchus baudinii) endemic to south-western Australia, so revegetation is important to their recovery. Over three years we studied cockatoo activity in 7–14-year-old mine-site rehabilitation in the region’s jarrah (Eucalyptus marginata)–marri (Corymbia calophylla) forest to give the most detailed description to date of the use of rehabilitation by the birds. Pits varied floristically and structurally (despite similar rehabilitation prescriptions), but interior and exterior plots (100 m2) were similar within pits. Using feeding traces (e.g. chewed husks), and behavioural observations we confirmed feeding within eight years of revegetation. Plots containing feeding trace were similar to plots without, so factors determining black cockatoo feeding may not be apparent at small scales. Returning food resources reflected vegetation succession, with regenerating marri and fast-maturing proteaceous species providing most food. Carnaby’s cockatoo ate Banksia and Hakea seeds and Baudin’s cockatoo and the forest red-tailed black cockatoo consumed marri seeds. Banksia squarrosa, Hakea undulata, H. prostrata and marri were common foods in all years. Revegetation efforts elsewhere should consider these species, within the constraints of rehabilitation protocols addressing multiple aims.

Identifying the relevant local population for environmental impact assessments of mobile marine fauna

Environmental impact assessments must be addressed at an appropriate scale of biological organization for the species affected. It can be challenging to identify the relevant local wildlife population for impact assessment for those species that are continuously distributed and highly mobile. Here, we document the existence of local communities of Indo-Pacific bottlenose dolphins (Tursiops aduncus) inhabiting coastal and estuarine waters of Perth, Western Australia, where major coastal developments have been undertaken or are proposed. Using sighting histories from a four-year photo-identification study, we investigated fine-scale, social community structure of dolphins based on measures of social affinity and network (Half-Weight Index - HWI, preferred dyadic association tests, and Lagged Association Rates - LAR), home ranges, residency patterns (Lagged Identification Rates - LIR), and genetic relatedness. Analyses revealed four socially and spatially distinct, mixed-sex communities. The four communities had distinctive social patterns varying in strength, site fidelity and residency patterns. Overlap in home ranges and relatedness explained little to none of the association patterns between individuals, suggesting complex local social structures. The study demonstrated that environmental impact assessments for mobile, continuously distributed must evaluate impacts in light of local population structure, especially where proposed developments may affect core habitats of resident communities or sub-populations. Here, the risk of local extinction is particularly significant for an estuarine community because of its small size, limited connectivity with adjacent communities, and use of areas subject to intensive human use. In the absence of information about fine-scale population structure, impact assessments may fail to consider the appropriate biological context.

Successional changes in feeding activity by threatened cockatoos in revegetated mine sites

Abstract Context. Provision of key habitat resources is essential for effectively managing species that have specific ecological requirements and occur in production landscapes. Threatened black cockatoos in the jarrah (Eucalyptus marginata) forest of Western Australia have a wide range, so their conservation requires support from all land tenures, not just reserves. Mining in the jarrah forest temporarily removes cockatoo feeding habitat, so it is important to understand how cockatoos exploit revegetated areas for food resources. Aims. We aimed to determine whether there were successional patterns in cockatoo feeding activity in revegetation aged from 4 to 23 years at three mine sites in the jarrah forest in south-western Australia. Methods. We surveyed 232 plots in revegetation to document (1) structural and floristic variation in vegetation across mine sites and revegetation ages, (2) differences in cockatoo feeding activity across mine sites and revegetation ages on the basis of feeding residues and (3) any edge effect reflecting preferential use of vegetation at the interior or exterior of mine pits. We also documented the frequency of occurrence of cockatoo food plants and feeding residues in 480 plots in unmined forest to compare with revegetated areas. Key results. Marri (Corymbia calophylla) and jarrah were commonly consumed in unmined forest and Banksia and Hakea species were also fed on to a lesser extent. Revegetated mine pits provided food within 4 years and continued to do so up until the oldest plots studied (23 years). The relative importance of food plants shifted from proteaceous species in young revegetation to myrtaceous species in intermediate to older revegetation. However, extent of feeding on myrtaceous species in older revegetation did not equate to feeding rates in unmined forest, with lower frequencies recorded in revegetation. Conclusions. Black cockatoos fed in revegetation at all three mine sites, despite variations in vegetation age, structure and floristics. Feeding on proteaceous and myrtaceous food plants occurred within 4 and 7 years of revegetation being established, respectively, indicating that some food resources are restored quickly after mining disturbance of the jarrah forest. Implications. Our results emphasise the importance of monitoring fauna recolonisation over appropriate time scales, to understand how successional processes in revegetation influence fauna population persistence in production landscapes.

The defamatory potential of ad hominem criticism: guidance for advocacy in public forums

Ad hominem criticism seeks to discredit an argument by attacking the qualities of the arguer, rather than the merits of the argument. Although there are compelling reasons to avoid ad hominem criticism, it may sometimes be appropriate as a means of responding to ‘expert’ arguments advanced in public forums. However, conservation biologists should evaluate the defamatory potential of any proposed ad hominem criticism and consider whether the criticism: (1) impugns a person’s reputation in a trade, profession or business; (2) has a factual grounding that is based on evidence that could be used in court; and (3) is better formulated as a statement of opinion than as a statement of fact. From a defamation perspective, the purpose and context for an ad hominem criticism is critical and conservation biologists should always consider whether, if viewed objectively, their conduct in making the criticism would be assessed as fair-minded, reasonable, and supportive of debate over an issue of public interest. Isolated and unsupported ad hominem remarks should not be made. Conservation biologists should also be aware that there are circumstances in which critiques of the methods, analyses, logical approaches, and conclusions of an expert could be said to be defamatory of that person, but that courts also recognise the importance of scientific debate. Conservation biologists should carefully consider the wording of any proposed ad hominem criticism, particularly in terms of the precise facts to be alleged and the particular evaluative words or phrases to be applied, and should also ensure that the criticism has a proper purpose, is well supported, and clearly distinguishes between comments that express an opinion and those that state a fact.

The invisible harm: land clearing is an issue of animal welfare

Abstract. Land clearing is a significant environmental issue in Australia and an area of active legislative reform. Despite evidence of the harm that land clearing causes to individual animals, such harm is either ignored or considered only indirectly in environmental decision-making. We argue that the harm that land clearing causes to animals ought to be identified and evaluated in decision-making relating to land clearing and consider the following three propositions in support: (1) land clearing causes deaths that are physically painful and psychologically distressing because of their traumatic and debilitating nature; (2) land clearing causes physical injuries, other pathological conditions, pain and psychological distress over a prolonged period as animals attempt to survive in the cleared environment or in the environments they are displaced to; and (3) on the basis of current clearing rates, more than 50 million mammals, birds and reptiles are likely to be killed annually because of land clearing in Queensland and New South Wales. The scientific consensus about the harm caused by land clearing means that decisions to allow land clearing are decisions to allow most of the animals present to be killed and, as such, frameworks for decision-making ought to include proper evaluation of the harm to be imposed.