Transpiration and groundwater uptake from farm forest plots of Casuarina glauca and Eucalyptus camaldulensis in saline areas of southeast Queensland, Australia

Plantings of salt-tolerant tree species are commonly used to manage shallow saline water tables in agricultural lands in Australia. Eucalyptus camaldulensis is often used for this purpose due to its salt tolerance and ability rouse groundwater. Salt tolerance studies suggest that Casuarina glauca would also have groundwater management potential, however, little is known about its transpiration and groundwater uptake properties. A combination of stable isotope (2H and 18O) techniques and sapflow measurements were used to determine groundwater discharge by both species at three saline sites. This included the use of a three-layer model for determining the proportions of water utilized from various soil depths. At one site, groundwater was the dominant water source for C. glauca in over 70% of sampling times. However, at a higher rainfall site, groundwater was the major water source for this species in only 40% of sampling times. E. camaldulensis relied less on groundwater than C. glauca, utilizing water from mid-soil layers to a greater extent. Groundwater was the dominant water source for this species in 50% and 25% of sampling times at each of the two sites, with lower use of groundwater at the higher rainfall site. Low water use rates were observed in both the species; 1.5 to 3 mm day-1 in C. glauca and 1 to 3 mm day-1 in E. camaldulensis. Due to the low water use rates, groundwater discharge rates seldom exceeded 2 mm day-1, with the maximum discharge rate of 2.6 mm day-1 being recorded for C. glauca. As C. glauca relied more heavily on groundwater than did E. camaldulensis, and both species exhibited conservative water use rates, under the conditions of this study, C. glauca showed greater potential than E. camaldulensis to discharge saline groundwater

What happens if we cannot fix it? Triage, palliative care and setting priorities in salinising landscapes

It is increasingly recognised that rising saline water tables present an unprecedented threat to both agricultural production and biodiversity conservation in the agricultural areas of Australia. In Western Australia, hydrological analysis is increasingly indicating that treatment of the problem will be difficult and costly, perhaps even impossible in some cases. Given the limited resources available for conservation management, there is a need to prioritise efforts and ensure that the level and type of management applied is both appropriate and likely to be effective. We discuss options for this in terms of ideas borrowed from healthcare provision, including triage and palliative care. We examine the range of management responses available in salinising landscapes in relation to the degree of threat, the relative value of the remnant or landscape and the likelihood of successful management intervention. While we certainly need to make a concerted effort to limit damage and loss as far as is possible, we also have to face the possibility that we cannot do this effectively everywhere, and that some areas will not be treated or treatable

Resilience in ecology: Abstraction, distraction, or where the action is?

Increasingly, the success of management interventions aimed at biodiversity conservation are viewed as being dependent on the 'resilience' of the system. Although the term 'resilience' is increasingly used by policy makers and environmental managers, the concept of 'resilience' remains vague, varied and difficult to quantify. Here we clarify what this concept means from an ecological perspective, and how it can be measured and applied to ecosystem management. We argue that thresholds of disturbance are central to measuring resilience. Thresholds are important because they offer a means to quantify how much disturbance an ecosystem can absorb before switching to another state, and so indicate whether intervention might be necessary to promote the recovery of the pre-disturbance state. We distinguish between helpful resilience, where resilience helps recovery, and unhelpful resilience where it does not, signalling the presence of a threshold and the need for intervention. Data to determine thresholds are not always available and so we consider the potential for indices of functional diversity to act as proxy measures of resilience. We also consider the contributions of connectivity and scale to resilience and how to incorporate these factors into management. We argue that linking thresholds to functional diversity indices may improve our ability to predict the resilience of ecosystems to future, potentially novel, disturbances according to their spatial and temporal scales of influence. Throughout, we provide guidance for the application of the resilience concept to ecosystem management. In doing so, we confirm its usefulness for improving biodiversity conservation in our rapidly changing world

Research priorities for the ghost bat (Macroderma gigas) in the Pilbara region of Western Australia

The ghost bat (Macroderma gigas) is Australia's largest echolocating bat. It is restricted to several disjunct populations in the north of the continent, including a population in the Pilbara region of Western Australia. In 2016 the ghost bat was listed as Vulnerable under Australian federal legislation, owing to declining numbers across many regional populations. The most severe threat to ghost bats in the Pilbara region is the destruction and disturbance of habitat due to mining operations, but disturbance to their roosts from other infrastructure developments and changes to and loss of foraging habitat also pose significant threats. A set of research priorities for ghost bats in the Pilbara was developed during a workshop attended by mining industry representatives, environmental consultants, scientists and government regulators. Five research priorities were identified: (1) identify and characterise critical diurnal roosts and foraging habitat; (2) improve knowledge of the distribution, movement and dispersal patterns of ghost bats in the region; (3) improve knowledge of population size, persistence and long-term trends; (4) better understand the cumulative, direct and indirect impacts of mining and other development activities; and (5) better understand the threats posed by fence entanglements, cane toads and feral cats