Gary A Kendrick

University of Western Australia | UWA · School of Biological Sciences and Oceans Institute

Understanding sexual reproduction and recruitment in seagrasses is crucial to their conservation and restoration. Flowering, seed production, seed recruitment, and seedling establishment data for the seagrass Posidonia australis was collected annually between 2013 and 2018 in meadows at six locations around Rottnest Island, Western Australia. Varia...

Understanding patterns of gene flow and processes driving genetic differentiation is important for a broad range of conservation practices. In marine organisms, genetic differentiation among populations is influenced by a range of spatial, oceanographic, and environmental factors that are attributed to the seascape. The relative influences of these...

Climate change and extreme climatic events, such as marine heatwaves (MHWs), are threatening seagrass ecosystems. Metabolomics can be used to gain insight into early stress responses in seagrasses and help to develop targeted management and conservation measures. We used metabolomics to understand the temporal and mechanistic response of leaf metab...

Abstract Refugia are habitats where species can survive or retreat to during environmental disturbances. One key assumption of habitats that constitute refugia is that they may assist in the persistence of impacted populations through the provision of reproductive propagules. This “reseeding” hypothesis assumes that demographic connectivity exists...

Historical and contemporary processes drive spatial patterns of genetic diversity. These include climate-driven range shifts and gene flow mediated by biogeographical influences on dispersal. Assessments that integrate these drivers are uncommon, but critical for testing biogeographic hypotheses. Here, we characterize intraspecific genetic diversit...

Coral reefs face increasing pressures in response to unprecedented rates of environmental change at present. The coral reef physical framework is formed through the production of calcium carbonate (CaCO3) and maintained by marine organisms, primarily hermatypic corals, and calcifying algae. The northern part of Western Australia, known as the Kimbe...

Restoration is an important activity to assist the recovery of damaged or degraded ecosystems. Accessing healthy donor material can be challenging when restoring threatened ecological communities, but careful selection of donor material may improve the success and cost‐effectiveness of restoration projects. We aim to optimise restoration of the thr...

Sulfide intrusion from sediments is an increasingly recognized contributor to seagrass declines globally, yet the relationship between sediment microorganisms and sulfide intrusion has received little attention. Here, we use metagenomic sequencing and stable isotope (34S) analysis to examine this relationship in Cockburn Sound, Australia, a seagras...

Seagrasses are an ecologically important group of plants that have returned to the sea from terrestrial ancestors on at least three occasions (Cymodoceaceae, Posidoniaceae, Zosteraceae). Seagrass-specific genomic adaptations to marine life are known from the Zosteraceae. However, independent lineages may have devised different solutions to life und...

The seed bank of Halophila ovalis is crucial for resilience to disturbance through re-establishment. Understanding seasonal changes in abundance and quality of seeds in natural seed banks is critical for seed-based restoration. We selected an estuary in southwestern Australia and investigated the seasonal changes of seed distribution and viability...

Monitoring of seagrasses has mainly relied on traditional seagrass metrics (e.g., biomass), which deliver reliable information about mortality but are unable to inform about impacts on seagrass health at the very early stages of stress exposure. Metabolomics is a novel molecular technique which can be used for early stress-detection in plants and a...

Plants endure environmental stressors via adaptation and phenotypic plasticity. Studying these mechanisms in seagrasses is extremely relevant as they are important primary producers and functionally significant carbon sinks. These mechanisms are not well understood at the tissue level in seagrasses. Using RNA-seq, we generated transcriptome sequenc...

Coral reefs face increasing pressures in response to unprecedented rates of environmental change at present. The coral reef physical framework is formed through the production of calcium carbonate (CaCO3) and maintained by marine organisms, primarily hermatypic corals, crustose coralline algae (CCA), and other calcifying algae. The Kimberley bioreg...

Polyploidy has the potential to allow organisms to outcompete their diploid progenitor(s) and occupy new environments. Shark Bay, Western Australia, is a World Heritage Area dominated by temperate seagrass meadows including Poseidon's ribbon weed, Posidonia australis. This seagrass is at the northern extent of its natural geographic range and exper...

The global carbon sequestration and avoided emissions potentially achieved via blue carbon is high (∼3% of annual global greenhouse gas emissions); however, it is limited by multidisciplinary and interacting uncertainties spanning the social, governance, financial, and technological dimensions. We compiled a transdisciplinary team of experts to elu...

This chapter summarizes our existing knowledge about seagrass seeds and their use and success in restoring seagrasses and enhancing recovery of damaged seagrass meadows, post-disturbance. The chapter is organised to introduce our interpretation of the evolution of these unique angiosperms, the processes of sexual reproduction, seed dormancy, seedli...

Over the past decades, ocean temperatures have been steadily increasing and are projected to continue to do so, stressing many temperate marine organisms. Changing temperatures do not affect ecosystems in isolation, but interact with many other factors in shaping ecological communities. We investigated the changes over 2 decades in subtidal tempera...

Globally marine-terrestrial interfaces are highly impacted due to a range of human pressures. Seagrass habitats exist in the shallow marine waters of this interface, have significant values and are impacted by a range of pressures. Cumulative risk analysis is widely used to identify risk from multiple threats and assist in prioritizing management a...

Seagrasses are globally recognized as bioindicators of marine eutrophication and contamination. Seagrasses also harbor a distinct root microbial community that largely reflects the conditions of the surrounding environment as well as the condition of the seagrass. Hence monitoring changes in the root microbial community could act as an additional b...

The Kimberley marine environment in Western Australia is widely recognised for its outstanding natural features, vast and remote sea and landscapes, and Indigenous cultural significance. To ensure that adequate baseline information is available to understand, monitor and manage this remote and relatively understudied region, scientific exploration...

Posidonia australis is a slow-growing seagrass that forms extensive meadows in sheltered coastal locations which are often popular areas for recreational boating. Traditional block-and-chain boat moorings can directly impact P. australis meadows, with the action of heavy chains eroding the seafloor and creating bare sand scars that fragment meadows...

The spatial genetic structure of marine organisms is related to dispersal and life-history traits, historical processes, current oceanographic connectivity and habitat features. Here, we assessed the relative importance of these factors for the genetic structure of a broad range of marine species in the Indo Australian Archipelago (IAA). We collate...

Seagrass meadows deliver important ecosystem services such as nutrient cycling, enhanced biodiversity, and contribution to climate change mitigation and adaption through carbon sequestration and coastal protection. Seagrasses, however, are facing the impacts of ocean warming and marine heatwaves, which are altering their ecological structure and fu...

Nature-based methods use the creation or restoration of coastal habitats for hazard risk reduction. This can be done through restoring the habitat alone (“soft” approach), or in combination with hard structures that support habitat establishment (“hybrid” approaches). The need to develop, test and apply more sustainable techniques to mitigate the i...

Herbivory is a key ecological process that often determines the composition and abundance of plants. Estimates of herbivory in seagrass meadows are typically lower than those in other vegetated coastal ecosystems, but herbivory can be intense when large herbivorous vertebrates are abundant. We surveyed rates of herbivory on 2 species of tropical se...

Cable bacteria are sulfide‐oxidising, filamentous bacteria that reduce toxic sulfide levels, suppress methane emissions and drive nutrient and carbon cycling in sediments. Recently, cable bacteria have been found associated with roots of aquatic plants and rice ( Oryza sativa ). However, the extent to which cable bacteria are associated with aquati...

Three case studies involving two temperate Australian seagrass species – Pondweed (Ruppia tuberosa) and Ribbon Weed (Posidonia australis) – highlight different approaches to their restoration. Seeds and rhizomes were used in three collaborative programmes to promote new approaches to scale up restoration outcomes.

Susan Lynn Williams (1951–2018) was an exceptional marine ecologist whose research focused broadly on the ecology of benthic nearshore environments dominated by seagrasses, seaweeds, and coral reefs. She took an empirical approach founded in techniques of physiological ecology. Susan was committed to applying her research results to ocean managemen...

Coastal marine ecosystems provide critical goods and services to humanity but many are experiencing rapid degradation. The need for effective restoration tools capable of promoting large-scale recovery of coastal ecosystems in the face of intensifying climatic stress has never been greater. We identify four major challenges for more effective imple...

Ecklonia radiata is the main foundation species in Australian temperate reefs, yet little has been published on its reproduction and how this may change across its depth range (1 - 50+ m). In this study, we examined the differences in sporophyte morphology and zoospore production during a reproductive season and across four depths (7, 15, 25 and 40...

Habitat availability underpins the diversity and distribution of benthic marine communities. Sponges are significant structural components of seabeds; therefore, understanding sponge-community associations are important for the effective management of marine biodiversity. Invertebrate communities were quantified from 11 sponge species having distin...

The seagrass Halophila ovalis rapidly colonizes marine sediments from seed across a range of depth, light, and temperature conditions, making it ideal for restoration projects. Yet, presently, it is not a targeted restoration species as the biology of seed dormancy and germination is poorly understood. This study addresses that knowledge gap by exp...

The marine angiosperm, Zostera marina, utilizes both asexual and sexual reproduction to grow, persist, and recover in dynamic environments. Sexual reproduction could be increasingly important for Z. marina population resilience to extreme weather events resulting from climate change. In the Chesapeake Bay, Virginia, a warming event in 2005 and unpr...

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...

Populations at the edges of their geographical range tend to have lower genetic diversity, smaller effective population sizes and limited connectivity relative to centre of range populations. Range edge populations are also likely to be better adapted to more extreme conditions for future survival and resilience in warming environments. However, th...

There is a growing emphasis on formally recognizing the connection to the marine environment of Indigenous peoples and the traditional ecological knowledge (TEK) these strong connections cultivate. The potential for TEK to significantly enrich the scientific comprehension of the marine environment, whilst also celebrating the rich bio-cultural know...

Seagrass meadows store globally significant organic carbon (Corg) stocks which, if disturbed, can lead to CO2 emissions, contributing to climate change. Eutrophication and thermal stress continue to be a major cause of seagrass decline worldwide, but the associated CO2 emissions remain poorly understood. This study presents comprehensive estimates...

Marine heatwaves (MHWs) have been documented around the world, causing widespread mortality of numerous benthic species on shallow reefs (less than 15 m depth). Deeper habitats are hypothesized to be a potential refuge from environmental extremes, though we have little understanding of the response of deeper benthic communities to MHWs. Here, we sh...

The increased occurrence of extreme climate events, such as marine heatwaves (MHWs), has resulted in substantial ecological impacts worldwide. To date metrics of thermal stress within marine systems have focussed on coral communities, and less is known about measuring stress relevant to other primary producers, such as seagrasses. An extreme MHW oc...

Across the globe, remote image data is rapidly being collected for the assessment of benthic communities from shallow to extremely deep waters on continental slopes to the abyssal seas. Exploiting this data is presently limited by the time it takes for experts to identify organisms found in these images. With this limitation in mind, a large effort...

Seeds of Australian species of the seagrass genus Posidonia are covered by a membranous wing that we hypothesize plays a fundamental role in seed establishment in sandy, wave swept marine environments. Dimensions of the seed and membrane were quantified under electron microscopy and micro-CT scans, and used to model rotational, drag and lift forces...

The development of early warning indicators that identify ecosystem stress is a priority for improving ecosystem management. As microbial communities respond rapidly to environmental disturbance, monitoring their composition could prove one such early indicator of environmental stress. We combined 16S rRNA gene sequencing of the seagrass root micro...

Underwater imaging is being extensively used for monitoring the abundance of lobster species and their biodiversity in their local habitats. However, manual assessment of these images requires a huge amount of human effort. In this article, we propose to automate the process of lobster detection using a deep learning technique. A major obstacle in...

Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO2 emission benefits of VCE conservati...

The seagrass Posidonia australis has suffered large reductions in distribution since the early to mid-1900s and as such has been listed as endangered in six estuaries in New South Wales, Australia, and as a ‘Threatened Ecological Community’ in estuaries from Wallis Lake to Port Hacking. One of the ongoing causes of losses of Posidonia in NSW estua...

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...

A central question in contemporary ecology is how climate change will alter ecosystem structure and function across scales of space and time. Climate change has been shown to alter ecological patterns from individuals to ecosystems, often with negative implications for ecosystem functions and services. Furthermore, as climate change fuels more freq...

Seafood certification and eco-labeling programs, which leverage market forces to incentivize fisheries improvements, have changed the face of the global seafood market through an expanding supply of and demand for certified seafood. To contribute towards conservation goals, these programs employ a strategy termed the ‘theory of change, which predic...

Across the globe, remote image data is rapidly being collected for the assessment of benthic communities from shallow to extremely deep waters on continental slopes to the abyssal seas. Exploiting this data is presently limited by the time it takes for experts to identify organisms found in these images. With this limitation in mind, a large effort...

Kelps (order Laminariales) are foundation species in temperate and arctic seas globally, but they are in decline in many places. Laminarian kelp have an alternation of generations and this poses challenges for experimental studies due to the difficulties in achieving zoospore release and gametophyte growth. Here, we review and synthesize the protoc...

Aim: To investigate how changing grid size can alter model predictions of the distribution of mesophotic taxa and how it affects different modelling methods. Location: Ningaloo Marine Park, Western Australia. Taxon: Benthic mesophotic taxa: corals, macroalgae and sponges. Methods: We determined the distributions of the major benthic taxonomic...

Hybridization is common among plants and has been crucial in the evolution of many aquatic plant groups. However, hybrid individuals are often difficult to identify, particularly in the marine environment. We aim to confirm a hybrid origin between two seagrass species for a morphologically-intermediate plant observed in shallow subtidal environment...

The role of environmental-stress gradients in driving trophic processes like grazing, has potential to shape ecosystem responses to environmental change. In subtidal seagrass systems, however, the variation in top-down processes along stress gradients are poorly understood. We deployed herbivory assays using the five most common seagrass species of...

Comprehensive list of fish species found in the Eastern embayment of Shark Bay, Western Australia. Table has been adapted from Travers and Potter (2002), Jackson et al. (2007), Belicka et al. (2012), Heithaus et al. (2012) and Walker et al. (2012). (DOCX)

Desalination has the potential to provide an important source of potable water to growing coastal populations but it also produces highly saline brines with chemical additives, posing a possible threat to benthic marine communities. The effects of brine (0%, 50%, 100%) were compared to seawater treatments with the same salinity (37, 46, 54 psu) for...

Fishery improvement projects (FIPs) are emerging as a popular market‐based means to improve fisheries sustainability and have been employed in scores of fisheries around the world; however, project ability to realize improvements has been highly variable, and little is known about how fishery and project conditions affect improvement efforts. In or...

Most of the world’s tropical coastal and shelf areas are heavily affected by anthropogenic activities, but the north-west shelf of Australia is considered a ‘very low-impact’ area. The role of herbivory on coral reefs is recognised, but most of that research comes from reefs with considerable land-based impacts. In this study we sampled the teleost...

In Australia, the states and territories have the primary responsibility for coastal waters. However, the Environmental Protection and Biodiversity Conservation (EPBC) Act 1999 describes when the Australian Federal Government needs can assist. The EPBC focusses on nine matters of national environmental significance (MNES). These include World Herit...

Aim Marine macrophytes are important components of tropical reefs that are influenced by environmental conditions and biotic interactions. Here, we aimed to identify the factors that shape macrophyte communities on shallow reefs in a region with limited anthropogenic impacts, but that is influenced by periodic disturbances from cyclones and marine...

Movement is fundamental to the ecology and evolutionary dynamics within species. Understanding movement through seed dispersal in the marine environment can be difficult due to the high spatial and temporal variability of ocean currents. We employed a mutually enriching approach of population genetic assignment procedures and dispersal predictions...

Connectivity of populations through the transfer of individuals is one of the key processes for maintaining ecosystem stability and resilience of coastal ecosystems. During reproduction, dislodged seaweeds of the genus Sargassum form large pelagic surface rafts that can persist for several weeks, and potentially act as a dispersal vector. In surfac...