Michael Alan Rasheed

James Cook University | JCU · Centre for Tropical Water & Aquatic Ecosystem Research

Current evidence suggests that there is a positive relationship between biodiversity and ecosystem functioning, but few studies have addressed tropical ecosystems where the highest levels of biodiversity occur. We develop two hypotheses for the implications of generalizing from temperate studies to tropical ecosystems, and discuss the need for more...

Coastal seagrass habitats are at risk from a range of anthropogenic activities that modify the natural light environment, including dredging activities associated with coastal and port developments. On Australia's east coast, the tropical seagrass Zostera muelleri ssp. capricorni dominates intertidal mudbanks in sheltered embayments which are also...

Global seagrass research efforts have focused on shallow coastal and estuarine seagrass populations where alarming declines have been recorded. Comparatively little is known about the dynamics of deep-water seagrasses despite evidence that they form extensive meadows in some parts of the world. Deep-water seagrasses are subject to similar anthropog...

Context Seagrasses form an important habitat that provides diverse ecosystem services essential for both the environment and people. In tropical Queensland, Australia, these meadows hold significant economic and cultural value, serving as nurseries for marine species and sustaining dugongs and green turtles. The biomass and size of tropical seagras...

The Gulf of Carpentaria and Torres Strait in north‐eastern Australia support globally significant seagrass ecosystems that underpin fishing and cultural heritage of the region. Reliable data on seagrass distribution are critical to understanding how these ecosystems are changing, while managing for resilience. Spatial data on seagrass have been col...

Vegetated coastal ecosystems, in particular mangroves, tidal marshes and seagrasses are highly efficient at sequestering and storing carbon, making them valuable assets for climate change mitigation and adaptation. The state of Queensland, in northeastern Australia, contains almost half of the total area of these blue carbon ecosystems in the count...

Report cards that are designed to monitor environmental trends have the potential to provide a powerful communication tool because they are easy to understand and accessible to the general public, scientists, managers and policy makers. Given this functionality, they are increasingly popular in marine ecosystem reporting. We describe a report card...

Full technical report can be accessed via GHHP's website: https://www.ghhp.org.au/technical-report

Seagrass habitats provide critical ecosystem services, yet there is ongoing concern over mounting pressures and continuing degradation. Defining a desired state for these habitats is a key step in implementing appropriate management but is often difficult given the challenges of available data and an evaluation of where to set benchmarks. We use mo...

The full technical report can be accessed directly via GHHP's webpage: https://www.ghhp.org.au/technical-report File URL: https://www.ghhp.org.au/_files/ugd/5c25a1_162c0c14a1954a77a8b4280d89062438.pdf

Biophysical models simulate dispersal and connectivity in marine environments by combining numerical models that represent water circulation with biological parameters that define the attributes of species. The effects of parameters, such as the number of particles released to simulate the trajectories of individual organisms, is potentially large...

The Great Barrier Reef World Heritage Area (GBRWHA) in north eastern Australia spans 2500 km of coastline and covers an area of ~ 350,000 km ² . It includes one of the world’s largest seagrass resources. To provide a foundation to monitor, establish trends and manage the protection of seagrass meadows in the GBRWHA we quantified potential seagrass...

Megaherbivore grazing (e.g. by turtles, and sirenians) plays a major and well-documented role in structuring seagrass meadows around the world; however, we know little about local-scale (intra- and inter-meadow) variability in megaherbivore grazing. This is surprising given that megaherbivores are highly selective eaters who may feed by targeting c...

Catchment impacts on downstream ecosystems are difficult to quantify, but important for setting management targets. Here we compared 12 years of monitoring data of seagrass area and biomass in Cleveland Bay, northeast Australia, with discharge and associated sediment loads from nearby rivers. Seagrass biomass and area exhibited different trajectori...

The Great Barrier Reef World Heritage Area in Queensland, Australia contains globally significant seagrasses supporting key ecosystem services, including habitat and food for threatened populations of dugong and turtle. We compiled 35 years of data in a spatial database, including 81,387 data points with georeferenced seagrass and species presence/...

Australia’s Great Barrier Reef (GBR) catchments include some of the world’s most intact coastal wetlands comprising diverse mangrove, seagrass and tidal marsh ecosystems. Although these ecosystems are highly efficient at storing carbon in marine sediments, their soil organic carbon (SOC) stocks and the potential changes resulting from climate impac...

Submerged aquatic vegetation (SAV; e.g. seagrasses, macroalgae), forms key habitats in shallow coastal systems that provide a plethora of ecosystem services, including coastal protection, climate mitigation and supporting fisheries production. Light limitation is a critical factor influencing the growth and survival of SAV, thus it is important to...

Grazing by all members of an herbivore community can act to structure the ecosystems they feed on. The outcome of this grazing pressure on the plant community also depends on the interaction between different herbivore groups that are present. We carried out a three-month multi-level field exclusion experiment to understand how different groups of...

The 2020 Gladstone Harbour Report Card reports on the environmental health of 13 reporting zones in and around Gladstone Harbour and the overall Environmental, Social, Cultural and Economic health of the harbour. This report card covers environmental monitoring undertaken in the period 1 July 2019 to 30 June 2020 and environmental, social, cultural...

Macroherbivory is an important process in seagrass meadows worldwide; however, the impact of macroherbivores on seagrasses in the Great Barrier Reef (GBR) has received little attention. We used exclusion cages and seagrass tethering assays to understand how the intensity of macroherbivory varies over space and time in the seagrass meadows around Gr...

The Great Barrier Reef (GBR) contains extensive seagrass meadows with abundant and diverse herbivore populations. Typically, meadows in the region are multi-species and dominated by fast growing opportunistic sea-grass species. However, we know little about how herbivores modify these types of seagrass meadows by grazing. We conducted the first meg...

Seagrass condition, resilience and ecosystem services are affected by the below-ground tissues (BGr) but these are rarely monitored. In this study we compiled historical data across northern Australia to investigate biomass allocation strategies in 13 tropical seagrass species. There was sufficient data to undertake statistical analysis for five sp...

The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption...

Consumer communities play an important role in maintaining ecosystem structure and function. In seagrass systems, algal regulation by mesograzers provides a critical maintenance function which promotes seagrass productivity. Consumer communities also represent a key link in trophic energy transfer and buffer negative effects to seagrasses associate...

Catchment activities, such as logging, grazing, agriculture and urbanization,generate elevated sediment loads which impact downstream water quality and coastal ecosystems. Quantifying the complex link between catchment sediment sources and downstream ecosystems is challenging but important for the development of reliable land-based ecologically rel...

Seagrasses are important marine ecosystems situated throughout the world’s coastlines. They are facing declines around the world due to global and local threats such as rising ocean temperatures, coastal development and pollution from sewage outfalls and agriculture. Efforts have been made to reduce seagrass loss through reducing local and regional...

Seagrass meadows are an important habitat for a variety of animals, including ecologically and socioeconomically important species. Seagrass meadows are recognised as providing species with nursery grounds, and as a migratory pathway to adjacent habitats. Despite their recognised importance, little is known about the species assemblages that occupy...

Implementing management actions to achieve environmental outcomes requires defining and quantifying ecological targets, but this is a complex challenge, and there are few examples of how to quantitatively set them in complex dynamic marine ecosystems. Here we develop a methodology to devise ‘desired state’ for tropical seagrasses in Cleveland Bay,...

Seagrass meadows are considered important natural carbon sinks due to their capacity to store organic carbon (Corg) in sediments. However, the spatial heterogeneity of carbon storage in seagrass sediments needs to be better understood to improve accuracy of Blue Carbon assessments, particularly when strong gradients are present. We performed an int...

All fishery food webs are ultimately underpinned by organic matter produced by algae and plants, some of it supplied by primary producers at the fringes of fish habitats. This is no different in tropical and subtropical estuaries where secondary production by crustaceans and finfish may depend on coastal wetlands (e.g. mangroves, seagrass, saltmars...

This technical report is the fifth annual report card of the Gladstone Healthy Harbour Partnership (GHHP). The 2019 Gladstone Harbour Report Card contains the results calculated using 33 indicators derived from 108 different measures within the four components of harbour health: Environment, Economic, Social, and Cultural. For further details visit...

Catchment degradation causing increased sediment flow is one of the key stressors facing Great Barrier Reef (GBR) habitats. Ecologically relevant targets (ERTs) for sediment and nutrient loads have been previously proposed based on seagrass light requirements, the next step is to connect these to ecological response. The overarching goal of the pre...

Catchment degradation causing increased sediment flow is one of the key stressors facing Great Barrier Reef (GBR) habitats. Ecologically relevant targets (ERTs) for sediment and nutrient loads have been previously proposed based on seagrass light requirements, the next step is to connect these to ecological response. The overarching goal of the pre...

Catchment degradation causing increased sediment flow is one of the key stressors facing Great Barrier Reef (GBR) habitats. Ecologically relevant targets (ERTs) for sediment and nutrient loads have been previously proposed based on seagrass light requirements, the next step is to connect these to ecological response. The overarching goal of the pre...

Structural habitat complexity is a fundamental attribute influencing ecological food webs. Simplification of complex habitats occurs due to both natural and anthropogenic pressures that can alter productivity of food webs. Relationships between food web structure and habitat complexity may be influenced by multiple mechanisms, and untangling these...

Understanding the relative influence of variables on ecosystem responses and the dynamics of their effect is necessary for effective ecosystem monitoring and management. Also known as causal pathways analysis, we develop an approach using functional Principal Components Analysis (fPCA) and machine learning within a scenario analysis framework. fPCA...

The 2018 Gladstone Harbour Report Card reports on the environmental health of 13 reporting zones in and around Gladstone Harbour and the overall environmental, social, cultural and economic health of the harbour. This report card covers monitoring undertaken in the period 1 July 2017 to 30 June 2018.

Shallow-water seagrasses capture and store globally significant quantities of organic carbon (OC), often referred to as 'Blue Carbon'; however, data are lacking on the importance of deep-water (greater than 15 m) seagrasses as Blue Carbon sinks. We compared OC stocks from deep-, mid-and shallow-water seagrasses at Lizard Island within the Great Bar...

Coastal development is contributing to ongoing declines of ecosystems globally. Consequently, understanding the risks posed to these systems, and how they respond to successive disturbances, is paramount for their improved management. We study the cumulative impacts of maintenance dredging on seagrass ecosystems as a canonical example. Maintenance...

Building on the 2016 report card, the Gladstone Harbour Report Card 2017 has been informed by 99 measures of the four components of harbour health: environmental, social, cultural and economic. This report card is based on data collected during the period from July 2016 to June 2017. As GHHP continues to expand and refine its monitoring programs, a...

Seagrasses are hugely valuable to human life, but the global extent of seagrass meadows remains unclear. As evidence of their value, a United Nations program exists (http://data.unep-wcmc.org/datasets/7) to try and assess their distribution and there has been a call from 122 scientists across 28 countries for more work to manage, protect and monito...

Seagrass meadows support key ecosystem services, via provision of food directly for herbivores, and indirectly to their predators. The importance of herbivores in seagrass meadows has been well-documented, but the links between food webs and ecosystem services in seagrass meadows have not previously been made explicit. Herbivores interact with ecos...

Better mitigation of anthropogenic stressors on marine ecosystems is urgently needed to address increasing biodiversity losses worldwide. We explore opportunities for stressor mitigation using whole-of-systems modelling of ecological resilience, accounting for complex interactions between stressors, their timing and duration, background environment...

Dredging can have significant impacts on benthic marine organisms through mechanisms such as sedimentation and reduction in light availability as a result of increased suspension of sediments. Phototrophic marine organisms and those with limited mobility are particularly at risk from the effects of dredging. The potential impacts of dredging on ben...

HIGHLIGHTS: Sedimentation of fine sediment particles onto seagrass leaves severely hampers the plants' performance in both light and darkness, due to inadequate internal plant aeration and intrusion of phytotoxic H2S. Anthropogenic activities leading to sediment re-suspension can have adverse effects on adjacent seagrass meadows, owing to reduced...

The 2016 Gladstone Harbour Report Card reports on the environmental health of 13 reporting zones in and around Gladstone Harbour and the overall environmental, social, cultural and economic health of the harbour. This report card covers monitoring undertaken in the period 1 July 2015 to 30 June 2016. The report can be downloaded using the following...

This project was initiated by the Gold Coast Waterways Authority (GCWA). The GCWA has created a Scientific Advisory Committee, which is in part responsible for the GCWA Scientific Research and Management Strategy and the accompanying Scientific Research and Management Program (SRMP). This project is part of that program and is intended to enhance u...

The Great Barrier Reef World Heritage Area (GBRWHA) is the jewel in Australia’s National Estate. It contains the world’s most extensive coral reef ecosystem—the only living organism distinguishable from space. Stretching 2,300 km along the Queensland coastline, it is the equivalent size of 70 million football fields and is home to approximately 3,0...

Seagrasses are important marine foundation species, which are presently threatened by coastal development and global change worldwide. The molecular mechanisms that drive seagrass responses to anthropogenic stresses, including elevated levels of nutrients such as ammonium, remains poorly understood. Despite the evidence that seagrasses can assimila...

Loads of suspended sediment, nutrients and pesticides discharged to the Great Barrier Reef (GBR) have increased greatly due to agricultural and urban development of the GBR catchment. As a result, in association with climate change impacts, the ecosystems of the GBR have degraded greatly in recent decades, and the decline in ecosystem health contin...

Aim The movement of propagules among plant populations affects their ability to replenish and recover after a disturbance. Quantitative data on recovery strategies, including the effectiveness of population connectivity, are often lacking at broad spatial and temporal scales. We use numerical modelling to predict seagrass propagule dispersal and se...

The northeastern Australian coastline from the tropics (10°S) to the subtropical zone of the southern Great Barrier Reef (GBR) and its World Heritage Area (25°S) is famous for coral reefs, a huge drawcard for the Australian tourist industry. Less appreciated but of at least equal importance to ecosystem functionality are the enormous seagrass meado...

The northeastern Australian coastline from the tropics (10°S) to the subtropical zone of the southern Great Barrier Reef (GBR) and its World Heritage Area (25°S) is famous for coral reefs, a huge drawcard for the Australian tourist industry. Less appreciated but of at least equal importance to ecosystem functionality are the enormous seagrass meado...

Seagrass meadows are threatened by coastal development and global change. In the face of these pressures, molecular techniques such as reverse transcription quantitative real-time PCR (RT-qPCR) have great potential to improve management of these ecosystems by allowing early detection of chronic stress. In RT-qPCR, the expression levels of target ge...

Seagrass ecosystems, considered among the most efficient carbon sinks worldwide, encompass a wide variety of spatial configurations in the coastal landscape. Here we evaluated the influence of the spatial configuration of seagrass meadows at small scales (metres) on carbon storage in seagrass sediments. We intensively sampled carbon stocks and othe...