Kieryn Kilminster

Unravelling complexity in seagrass systems for management: Australia as a microcosm

Environmental decision-making applies transdisciplinary knowledge to deliver optimal outcomes. Here we synthesise various aspects of seagrass ecology to aid environmental decision-making, management and policy. Managers often mediate conflicting values and opinions held by different stakeholders. Critical to this role is understanding the drivers for change, effects of management actions and societal benefits. We use the diversity of seagrass habitats in Australia to demonstrate that knowledge from numerous fields is required to understand seagrass condition and resilience. Managers are often time poor and need access to synthesised assessments, commonly referred to as narratives. However, there is no single narrative for management of seagrass habitats in Australia, due to the diversity of seagrass meadows and dominant pressures. To assist the manager, we developed a classification structure based on attributes of seagrass life history, habitat and meadow form. Seagrass communities are formed from species whose life history strategies can be described as colonising, opportunistic or persistent. They occupy habitats defined by the range and variability of their abiotic environment. This results in seagrass meadows that are either transitory or enduring. Transitory meadows may come and go and able to re-establish from complete loss through sexual reproduction. Enduring meadows may fluctuate in biomass but maintain a presence by resisting pressures across multiple scales. This contrast reflects the interaction between the spatial and temporal aspects of species life history and habitat variability. Most management and monitoring strategies in place today favour enduring seagrasses. We adopt a functional classification of seagrass habitats based on modes of resilience to inform management for all seagrass communities. These concepts have world-wide relevance as the Australian case-studies have many analogues throughout the world. Additionally, the approach used to classify primary scientific knowledge into synthesised categories to aid management has value for many other disciplines interfacing with environmental decision-making.

Transdisciplinary synthesis for ecosystem science, policy and management: The Australian experience

Mitigating the environmental effects of global population growth, climatic change and increasing socio-ecological complexity is a daunting challenge. To tackle this requires synthesis: the integration of disparate information to generate novel insights from heterogeneous, complex situations where there are diverse perspectives. Since 1995, a structured approach to inter-, multi- and trans-disciplinary(1) collaboration around big science questions has been supported through synthesis centres around the world. These centres are finding an expanding role due to ever-accumulating data and the need for more and better opportunities to develop transdisciplinary and holistic approaches to solve real-world problems. The Australian Centre for Ecological Analysis and Synthesis (ACEAS ) has been the pioneering ecosystem science synthesis centre in the Southern Hemisphere. Such centres provide analysis and synthesis opportunities for time-pressed scientists, policy-makers and managers. They provide the scientific and organisational environs for virtual and face-to-face engagement, impetus for integration, data and methodological support, and innovative ways to deliver synthesis products. We detail the contribution, role and value of synthesis using ACEAS to exemplify the capacity for synthesis centres to facilitate trans-organisational, transdisciplinary synthesis. We compare ACEAS to other international synthesis centres, and describe how it facilitated project teams and its objective of linking natural resource science to policy to management. Scientists and managers were brought together to actively collaborate in multi-institutional, cross-sectoral and transdisciplinary research on contemporary ecological problems. The teams analysed, integrated and synthesised existing data to co-develop solution-oriented publications and management recommendations that might otherwise not have been produced. We identify key outcomes of some ACEAS working groups which used synthesis to tackle important ecosystem challenges. We also examine the barriers and enablers to synthesis, so that risks can be minimised and successful outcomes maximised. We argue that synthesis centres have a crucial role in developing, communicating and using synthetic transdisciplinary research.

Microbial colonization in the seagrass Posidonia spp. roots

Abstract The pattern of colonization by microorganisms on root surfaces from three species of seagrass belonging to the genus Posidonia was assessed. Microbial abundance on roots was measured by two electronic microscope techniques. Trends in microbial colonization between species and root order were defined. In addition, eutrophication status of the sampling sites and physiological status of Posidonia oceanica (L.) Delile roots have been taken into account. Our results show high microbial abundance in the Mediterranean species P. oceanica, in comparison with the low rates of colonization found in the Australian species P. australis Hook f. and P. sinuosa Cambridge et Kuo. Microbial density tended to decrease as root order increased, and living roots always showed higher microbial abundance than dead ones. Colonization of P. oceanica roots at the three sites with different environmental status follows different trends according to root order. It is suggested that root age influences the rate of microbial colonization of seagrass roots and that colonization of root surface by microorganisms is associated with organic exudates from the roots rather than with decaying root tissues.

Trace element content of seagrasses in the Leschenault Estuary, Western Australia

Estuarine environments are particularly vulnerable to human impacts. In this study, trace elements in Ruppia megacarpa, Halophila ovalis, sediment and porewater were analysed to assess the potential contamination of the Leschenault Estuary, Western Australia, from a primarily agricultural drain. Sediment concentrations of Cd, Cu, Mn, and Ni and were highest nearest the drain while Al, As, Cr, Fe and Zn and were highest further from the drain. H. ovalis showed greater accumulation of Fe, Al, and As than R. megacarpa. Concentrations of Fe, Al, As, and Ni were generally higher in below-ground plant parts than above, suggesting uptake of these trace elements via the sediment-route pathway. This study suggested that the drain was a source of Cu and Mn, with these elements entering the estuary through water inflows. As and Fe, were highest furthest from the drain suggesting input of trace elements from sources other than the drain under study.

A sulfur-stable-isotope-based screening tool for assessing impact of acid sulfate soils on waterways

Early warning indicators for waterways affected by acid sulfate soils (ASS) are valuable tools for water management organisations. Oxidised ASS may discharge high concentrations of metals, acid and sulfur to surrounding water. The origin of sulfate may be determined by d 34 S values. d 34 S values of dissolved sulfate in ,300 samples of fresh, brackish and estuarine surface water from south-west Western Australia ranged from � 6.6 to 31.4% (Canon Diablo Troilite). An indicator was developed based on (SO4� ), (Cl � ) and d 34 S that categorised samples into groups with similar isotopic influences (iso-groups). Signals of disturbed ASS were identified in ,4.5% of sites. Multivariate statistical analysisshowedthatwaterqualityhaddeterioratedatASS-influencedsites.Althoughhighlyvariable,averagealuminium concentrations were higher (up to 0.12mgL � 1 , compared witho0.05mgL � 1 elsewhere) in samples that are influenced by ASS disturbance. The categorisation of samples into iso-groups provides a simple tool to prioritise sites for further investigation. This study shows that d 34 S values provide an early warning indicator for water affected by disturbed ASS, particularly in localities where rainfall is marine dominated with a similar d 34 S to seawater.

Seagrass ecosystem trajectory depends on the relative timescales of resistance, recovery and disturbance

Seagrass ecosystems are inherently dynamic, responding to environmental change across a range of scales. Habitat requirements of seagrass are well defined, but less is known about their ability to resist disturbance. Specific means of recovery after loss are particularly difficult to quantify. Here we assess the resistance and recovery capacity of 12 seagrass genera. We document four classic trajectories of degradation and recovery for seagrass ecosystems, illustrated with examples from around the world. Recovery can be rapid once conditions improve, but seagrass absence at landscape scales may persist for many decades, perpetuated by feedbacks and/or lack of seed or plant propagules to initiate recovery. It can be difficult to distinguish between slow recovery, recalcitrant degradation, and the need for a window of opportunity to trigger recovery. We propose a framework synthesizing how the spatial and temporal scales of both disturbance and seagrass response affect ecosystem trajectory and hence resilience.

A Barium Vanadium(v) Selenite Hydrate, Ba(VO2)2(SeO3)2·H2O: A Novel 3D Polymer of Cross-Linked Sheets with Embedded ···V-O-V··· 21 Helices

The characterisation, by a single-crystal X-ray study at ~150u2009K, of brown acicular crystals of barium(ii) bis(dioxovanadium(v)) bis(selenite(iv)) monohydrate, BaSe2V2O10·H2O, obtained as a minor product of the synthesis of the previously reported ‘Ba(VO)2(SeO3)2(HSeO3)2’, is recorded. Crystals are monoclinic, P21/c, au2009=u200910.803(2), bu2009=u20095.1126(8), cu2009=u200917.905(3)u2009A, βu2009=u200992.048(2)°, Vu2009=u2009988.3(3)u2009A3, 2456 independent diffractometer reflections refining to R1u2009=u20090.032, wR2u2009=u20090.084. A single BaV2Se2O11H2 formula unit, devoid of crystallographic symmetry, comprises the asymmetric unit of the structure, which is a three-dimensional polymer, with component sheets parallel to the crystallographic b axis, containing pentavalent vanadium atoms, one five-, the other six-coordinate, linked by selenite pyramids.

Seagrasses of Southern and South-Western Australia

The coastal waters of southern and south-western Australia are home to almost 30,000 km2 of seagrass, dominated by temperate endemic species of the genera Posidonia and Amphibolis. In this region, seagrasses are common in estuaries and sheltered coastal areas including bays, lees of islands, headlands, and fringing coastal reefs. Additionally, extensive meadows exist in the inverse estuaries of the Gulfs in South Australia, and in Shark Bay in Western Australia. This chapter explores (i) how geological time has shaped the coastline and influenced seagrasses, (ii) present day habitats and drivers, (iii) how biogeography patterns previously reported have been altered due to anthropogenic and climate impacts, and (iv) emerging threats and management issues for this region. Species diversity in this region rivals those of tropical environments, and many species have been found more than 30 km offshore and at depths greater than 40 m. Seagrasses in this region face a future of risk from multiple stressors at the ecosystem scale with coastal development, eutrophication, extreme climate events and global warming. However, our recent improved understanding of seagrass recruitment, restoration and resilience provides hope for the future management of these extraordinary underwater habitats.