Ecocene

With an increase in flooding events around large parts of the country and risks associated with sea level rise and coastal inundation, mapping of flood-prone and inundated areas is critical. Astron can provide flood risk assessments and monitor changes in water levels and extent using a range of remote sensing imagery and approaches.

Our Earth Observation team can integrate remotely sensed data including multi- and hyperspectral, thermal and SAR imagery from satellite and UAV to map water bodies and levels related to wetlands, coastal inundation, inland flooding along rivers and lakes, and changes in tidal levels in coastal regions.

A combination of time series data from satellite imagery, field observations and station discharge data can be used to model seasonal flooding patterns and changes in sea level. In addition, elevation data from LiDAR or satellite-derived digital elevation models (DEM) can be integrated to generate flood models.

“The early bird catches the worm“

Astron's environmental scientists enthusiastically embrace early mornings. We take pleasure in immersing ourselves in the breathtaking beauty of the Pilbara landscape during this serene part of the day while diligently carrying out environmental monitoring tasks. Engaging in the role of an environmental scientist entails a dynamic combination of fieldwork, collaboration, problem-solving a commitment to environmental conservation. It's a career path that requires a solid foundation in science, adaptability, and a passion for making a positive difference.

Rapid, low-cost indicators of biodiversity are needed to track large scale restoration projects. Structural complexity from remote sensing is an indicator with potential, as a more complex vegetation structure often reflects higher plant species richness and diversity of habitat. We have been exploring the structural complexity metrics from aerial image and LiDAR data. This includes the Rumple index - a ratio of canopy surface area to ground surface area. While such metrics are an attractive option, some form of on-ground survey is always going to be needed for verification, which is where Astron’s highly skilled field team comes in.

Our team has been hard at work in the shallow water mapping space developing advanced approaches for benthic habitat and geomorphic mapping from a range of remotely sensed data. Partnering up with EOMAP for supply of water column corrected satellite data, we apply our remote sensing expertise on high quality, fit-for-purpose seafloor reflectance (SFR) and satellite-derived bathymetry (SDB).

Complemented by multibeam/sidescan sonar data over deeper water, as well as LiDAR, SAR and drone imagery over shallow water, we can successfully produce water-based mapping outputs covering the intertidal and subtidal zones to support environmental monitoring requirements.

Our team can further integrate water quality products (e.g. turbidity, Chlorophyll-a, harmful algal blooms), supplied by our partner EOMAP, to address our client’s water quality monitoring requirements.

Credits:
WorldView © 2023 Maxar Technologies.
Director of National Parks (Parks Australia), Ashmore Reef and Cartier Island SDB/Reflectance ©EOMAP, 2023 (CC-BY 4.0)

Astron took part in R U OK? Day on Thursday the 14th of September by holding a morning tea in our East Perth office. We got together to highlight the importance of checking in with each other and how to ask those questions to see if they are okay or they are having a hard time.

During our lovely morning tea, which was supplied by multiple staff members to cater for any and all requirements to make everyone feel included and celebrated, we spent some time focusing on how our work at Astron can continue to foster a supportive environment and to show that there is always support for those who might be struggling, whether it be someone in the field or in the office.

R U OK? Day encourages us to start those conversations if we’ve noticed changes in someone, whether it’s a family member, colleague or friend. The hardest step for someone who is battling can be reaching out for help. But when someone asks if they ‘R OK’, it can show that person that they are supported. Even if someone is okay, the knowledge that you are someone safe they can ask in the future can ease those struggles.

In celebration of National Threatened Species Day 2023, we would like to share some pictures of some adorable threatened species our zoology team recently had the pleasure of working with.

The Burrowing Bettong (Boodie) used to be widespread on the mainland but they are now only found on a number of offshore islands or in predator-free exclosures on the mainland where they have been reintroduced. The Golden Bandicoot and Brushtail Possum were some of the bycatch our team encountered on the recent trip and I think we can all agree that is some pretty special bycatch!

https://wwf.org.au/what-we-do/species/national-threatened-species-day/

Thermal imagery can be used to assess vegetation water status and groundwater dependency. Cooler leaves, for example, suggest a more favourable water status, which could be indicative of groundwater dependency. Sources of thermal data include high-resolution imagery from drones and the archive of imagery from Landsat satellites which can be used to calculate land surface temperature (LST). Broad changes in LST can also relate to fluctuations in canopy cover owing to drought, fire or clearing – a reduction in canopy usually results in higher LSTs.

These processes are captured in the LST change image (average change across summer months from 1987 -2021) for Kings Park, located next to the Perth CBD. The area of LST increase at the northern end of the park, for example, was burnt in 2018. The distinct increase in LST at the eastern margin of the park was brought about by removing pine trees and installing roofing over a reservoir.

Fueled by Astron’s strong focus on R&D, our Earth Observation team is exploring the potential of hyperspectral satellite imagery for detailed spectral discrimination of mangrove communities and coastal vegetation. Further to assessing vegetation health/stress across these sensitive ecosystems, hyperspectral data may also enable the assessment of structural and compositional indicators for biodiversity to monitor species richness and abundance.

In addition to testing a number of narrow-band indices to derive vegetation and soil characteristics, trials for machine learning and deep learning are also underway on hyperspectral data. The team is assessing imagery from the and hyperspectral satellites and looking to expand trials into the realm of very high resolution hyperspectral imagery from UAV/aerial platforms.

FLORA AND VEGETATION – GROUNDWATER DEPENDENT VEGETATION MONITORING, PART 2

One informative method to monitor the water status of groundwater dependent vegetation is to measure leaf water potential or ‘water pressure’, which can be thought of as being similar to measuring ‘blood pressure’ in humans. Leaf water potential describes the average 'demand' for water within the plant and is a leading indicator of water stress.

Leaf water potential is measured on sampled leaves using a Scholander-type pressure chamber. This is a rapid, simple and reliable method that has been used for decades by plant scientists. Predawn measurements of leaf water potential can be used as an indicator of soil water availability and base levels of water stress. Midday measurements are indicative of peak water stress, when evaporative demand, transpiration rates and soil water depletion are at their highest within a day.

If you would like to know more, please don’t hesitate to get in touch with Astron’s Earth Observation team.

FLORA AND VEGETATION – GROUNDWATER DEPENDENT VEGETATION MONITORING, PART 1
Groundwater dependent vegetation (GDV) is a major component of groundwater dependent ecosystems and plays an important ecological role in arid environments by supporting biological diversity and productivity. GDV also plays a key role in water resource management as it connects landscapes and groundwater. Monitoring GDV is often a regulatory requirement where dewatering operations associated with mining may impact groundwater and surface water regimes.

GDV monitoring programs are typically designed to detect ecologically significant change in tree health, spatial structure, and/or community composition in relation to baseline conditions. Monitoring methods vary according to the nature of the risks and can include quantitative and qualitative measures of tree water status, health, and condition. In addition, remote sensing methods using UAV and satellite imagery are included as best-practice to provide a holistic approach to monitor GDV health over time.
Stay tuned to see how we are incorporating quantitative ecophysiology methods into monitoring programs to assess potential impacts to GDV health.