Australia has the world's most diverse terrestrial orchid flora, and our orchid species are characterised by very high rates of endemism. However, Australian native orchids are highly susceptible to environmental change and account for 17% of nationally threatened plant species. Recent studies have highlighted climate change, florivory, altered fire regimes and pollination deficits as stressors that are contributing to orchid decline, and many questions on their taxonomy and ecology remain unanswered. Orchids are often cryptic, population sizes and short flowering times vary with season, and they are sporadically distributed across Australia, making it difficult to obtain data using traditional methods. Wild Orchid Watch (WOW) is a national citizen science program designed to create and facilitate public uptake of an app, and the systems behind it, to collect a suite of information on orchids and their habitats. The WOW app will guide users to make a series of observations in the field, collecting information designed to be of maximum relevance to scientists, such as photographs, habitat details and location. Our program builds on the growing momentum for citizen science in Australia, harnessing the knowledge and expertise of orchid enthusiasts who are keen to get involved. Data collected by citizen scientists using the WOW app will allow researchers to understand the value of orchids as indicators of environmental change, as well as provide fundamental information on orchid distribution, abundance, and phenology, all of which are critical to assigning conservation status.

It is imperative, as ecologists, that we provide university students with quality ecological experiences that excite, inspire and demonstrate the importance of the field. Arguably, the best way to achieve this is by developing learning experiences that challenge students with real-world applied ecological problems and allow them to design and implement experiments addressing these issues. We developed a unique educational experience, the Sydney Park project, for first year students enrolled in a large generalised biology course. These students undertake a research project in partnership with the City of Sydney Council at Sydney Park, Sydney, Australia. To date, the Council has limited information on invertebrate biodiversity of Sydney Park. In this project, students propose their own urban ecology research question, design and set up their experiment and do all subsequent data analyses and identification of invertebrates. They are then formally assessed via a scientific report and the Council gains invaluable data on patterns on invertebrate diversity. We suggest that this approach increases the authenticity of the experience and assessment by providing beneficial outcomes for both stakeholders. This also provides students with a tangible understanding of the importance of ecology in their everyday lives and leads to a deeper understanding of the complexities of performing biodiversity assessments in urban environments. Consequently, the Sydney Park project provides clear links between University assessments and real-world management outcomes. But it’s no walk in the park…

Drought is leading to forest mortality across the globe with implications for forest ecosystems, biodiversity and the earth’s carbon budget. As more frequent and severe droughts are predicted into the future it is critical that we understand the mechanisms which lead to drought-induced tree death. Failure of the plant water transport system due to the formation of air bubbles, called ‘xylem cavitation,’ has been identified as a causal factor in tree death due to drought. Until recently, xylem cavitation could not be measured in-situ due to limitations associated with techniques.
Here we use a new, non-invasive method called the Optical Technique to study the temporal and spatial spread of drought-induced xylem cavitation in a highly drought resistant Australian species, Callitris rhomboidea. We attached cameras to branches at various heights in Callitris saplings to visualise the spread of xylem cavitation through trees under drought conditions, which we combined with simultaneous measurements of water stress. We found variation in the timing and levels of water stress associated with the onset of xylem cavitation and complete vascular failure among branches, with both onset and failure occurring first in the lowest branches. The Optical Technique can be used to identify the water stress thresholds which incur death and damage in branches, leaves and roots in all trees. Therefore, this method has the potential to characterise the drought-vulnerability of whole forests. This information could be used to inform models to predict forest damage and mortality with implications for managing forests in a drying world.

Many of the world’s digging animals are considered ecosystem engineers due to the functional role they provide in landscapes. As digging animals create burrows or forage for food they disrupt and modify the ground’s surface, often changing litter distribution and availability, potentially altering fuel loads. Fire management in many landscapes, including peri-urban areas, is complex and challenging. The reintroduction of previously common digging animals, some of which are now threatened, may have the added benefit of reducing fuel loads. We experimentally examined how the reintroduction of a marsupial bandicoot, quenda (Isoodon fusciventer), altered surface fuel loads in an urban banksia woodland bush reserve in Perth, Western Australia. Within four years of reintroduction, foraging activities of quenda (where they dig for subterranean food) were substantial throughout the reserve and had significantly reduced litter cover and depth in open plots where quenda had access. In addition, estimated surface fuel loads were nearly halved in open plots where quenda foraged compared to fenced plots where quenda were excluded (3.6 c.f. 6.4 tonnes ha-1). Fire behaviour modelling indicated the predicted rate of spread of fire were significantly lower for open plots compared to fenced plots under both low and high fire conditions. Although many environments require fire, urban bushland reserves pose many fire management challenges because they are typically small and close to human infrastructure. The reintroduction of previously common digging species may have potential value as a complimentary tool for reducing fuel loads, and potentially, fire risk.

Predation of eggs is a major contributor to the decline of shorebird populations. Egg predators use an array of olfactory and visual cues to locate eggs. However, as precocial avian embryos approach hatching, vocalisations emanate from within the egg and may inadvertently act as auditory cues by predators to locate otherwise cryptic eggs. This study investigated the embryonic vocalisations emitted from eggs of a shorebird species, the Red-capped Plover Charadrius ruficapillus. We characterised the acoustic properties of the vocalisations and the circumstances under which they were emitted, then tested whether such vocalisations are used as an acoustic cue by predators to locate eggs. Embryonic vocalisations typically occurred between 0 and 5 days before hatching, and the nature of these calls (e.g. acoustic frequency range) could be influenced by age and temperature. An artificial nest experiment compared the survival of nests with and without acoustic cues (pre-recorded embryonic vocalisations played continuously from the nest). Corvids were the major egg predator (accounting for 76% of cases of artificial nest predation). However, the presence of vocalisations did not affect the time taken for predators to locate and depredate eggs. Our results suggest that embryonic vocalisations are important signals that may aid in communication with parents but they do not increase predation rates in this predator regime, where visually foraging predators are the predominant predator. Further research involving a greater diversity of predators (e.g. acoustic predators) is required to examine whether vocalisations from the egg incur costs under other predator regimes.

Over the past two decades, there has been significant conversion of cleared agricultural land to eucalyptus plantations across much of Australia. These plantations provide habitat for koalas and can facilitate increases in the abundance of koalas in plantation dominated landscapes. Whilst an increase in the number of koalas can be viewed as a positive conservation outcome associated with plantations, it may also pose koala welfare issues associated with plantation harvesting, and raises concerns for the conservation of nearby remnant native vegetation as koalas disperse. We used GPS loggers and radio tracking to examine koala habitat use of two landscape types: a plantation-dominated landscape, and a highly cleared agricultural landscape. Total range sizes did not differ between the two landscape types, and range sizes in both landscapes were relatively small (average size of 1 hectare for males and 0.8 hectares for females). Koalas used plantations when available, with up to 60% of animals using plantations, however, koalas showed selection for native habitat over plantations. The use of plantations by koalas in this study demonstrates their potential for providing additional habitat and connectivity. However, it also highlights the importance of native vegetation for the persistence of koalas in both plantation-dominated habitats and agricultural landscapes. Thus, we highlight the importance of planting and harvesting practices that consider overall landscape configuration as well as the spatial arrangement of plantations adjacent to remnant forest.

Since timber harvesting reduces the average age of forests, management needs to ensure that mature forest habitat values are available within production landscapes. This is especially important in the Eucalyptus regnans forests in Victoria’s Central Highlands, where several wildfires over the last hundred years mean that very little old-growth forest remains. Mature habitat values within the dominant 1939 regrowth age cohort are thus very important for biodiversity. We used GIS layers for crown senescence and productivity, combined with field surveys, to assess floristic and structural habitat values in 1939 regrowth stands. GIS layers had rather weak predictive capacity for identifying stands with greater maturity. The proportion of senescent trees was related to the density of old-growth eucalypts, the size of both live and dead eucalypts, the likelihood of tree hollows and the volume of coarse woody debris. Thus, crown senescence has a degree of utility for strategic planning to protect habitat trees. Site productivity was weakly related to floristic composition, but not to the likelihood of rainforest plant species. More productive sites did not have greater maturity values. Inclusion of additional environmental variables (climate, soils, topography, structure and spatial location) did not substantially improve explanatory power. These results contrast with similar work in Tasmania where forest maturity values could be predicted more easily, probably because only a single age cohort was sampled in Victoria. We conclude that it is difficult to predict areas of 1939 regrowth with high structural and floristic maturity within forests available for timber production.

Eucalyptus marginata, one of the dominant tree species of Western Australia (WA), is used as timber, firewood, wildlife habitat, water regulation and greenery. To better understand its growth, a low thinning trial (4 thinning grades and one unthinned) was started in 1965 in Inglehope, WA. In 1987, a second thinning and fertilizer treatment was applied. The effect of thinning and fertilizer on tree allometry and growth (diameter at breast height (dbh), height and basal area (BA)) was evaluated for 1965-2010. Allometric relationships among dbh, height, crown-width (k), slenderness-coefficient, k/dbh ratio and bark-thickness were fitted, and we tested whether these were affected by the treatments. Thinning had a significant effect on all allometric relationships but fertilizer only affected dbh with height, slenderness-coefficient and bark-thickness. Height, crown-width and bark-thickness increased with increase in dbh but slenderness-coefficient decreased. The dbh and BA growth increased with increase in thinning intensity. Trees in heavily thinned plots had 6.38 times dbh growth than those in unthinned plots, and 12.85 times BA growth. Fertilized trees had 1.11 and 1.25 times dbh growth than unfertilised in heavily thinned and unthinned plots respectively. Height growth didn’t vary significantly with thinning. Stand BA peaked at intermediate stand densities and was lower in unthinned and heavily thinned plots. The self-thinning in E. marginata was 0.20% yr-1 which is very low compared to other species and the growth is least in the unthinned plots. Thinning can be an efficient management tool to maximize the benefit from the forest.

Recent studies suggest that habitat amount is the main determinant of species richness, whereas habitat fragmentation has weak and mostly positive effects. Here, we challenge these ideas using a multi-taxa database including 2230 estimates of forest-dependent species richness from 1097 sampling sites across the Brazilian Atlantic Forest biodiversity hotspot. We used a structural equation modeling approach, accounting not only for direct effects of habitat loss, but also for its indirect effects (via habitat fragmentation), on the richness of forest-dependent species. We reveal that in addition to the effects of habitat loss, habitat fragmentation has negative impacts on animal species richness at intermediate (30-60%) levels of habitat amount, and on richness of plants at high (> 60%) levels of habitat amount, both of which are mediated by edge effects. Based on these results, we argue that dismissing habitat fragmentation as a powerful force driving species extinction in tropical forest landscapes is premature and unsafe.

Coarse woody debris (CWD) is an important contributor to forest biodiversity because it provides essential habitat for saproxylic (dead wood-dependent) species. However, CWD is frequently overlooked in forest management and restoration decisions around the world. To make conducting CWD assessments more manageable and consistent, we have developed an index of CWD habitat quality that integrates four important characteristics of saproxylic habitat. We have also developed a web app that calculates CWD habitat quality scores from raw field measurements. The index and app can be applied directly to wet eucalypt forests in Tasmania, and are suitable for any forest system for which reference data sets are available. The index can be used in conservation assessments to determine habitat availability for biodiversity, and to quantify the impacts of management actions and restoration activities. The CWD index is only weakly related to standing forest structural and floristic maturity metrics in Tasmanian wet eucalypt forests (R² < 0.09), highlighting the necessity to explicitly factor CWD habitat into conservation planning. Variables linked to future CWD quality (standing tree basal area and the number of old-growth eucalypts) have hump-shaped relationships with current CWD habitat quality, implying that stands with medium current quality provide better potential future habitat than stands with high current quality. CWD habitat quality was lower in previously harvested stands.