Timothy M. Smith

James Cook University · Centre for Tropical and Freshwater Research (TropWATER)

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...

Seed size can have an impact on angiosperm reproductive fitness. Ecological theory predicts plants that will produce larger seeds in stressful environments to increase the chances of seedling survival and numerous small seeds in favourable conditions to increase the number of recruits. We measured seed morphology of the seagrass Heterozostera nigri...

The endangered soft coral Dendronephthya australis faces substantial population decreases in central eastern Australian waters. Despite uncertainty about the cause of these declines, the population genetics of the species has not been investigated. Genetic analysis suggests that D. australis is a single species within the family Nephtheidae, confir...

Rationale: Stable isotopes are used to study trophic and movement ecology in aquatic systems, as they provide spatially distinct, time-integrated signatures of diet. Stable isotope ecology has been used to quantify species-habitat relationships in many important fisheries species (e.g., penaeid prawns), with approaches that typically assume consta...

Seagrass ecosystems have suffered significant declines globally and focus is shifting to restoration efforts. A key component to successful restoration is an understanding of the genetic factors potentially influencing restoration success. This includes understanding levels of connectivity between restoration locations and neighbouring seagrass pop...

Estuaries represent highly important nursery habitats for a range of species, with refuge and nutrition being two key benefits derived from estuaries. Quantifying these benefits provides us with a means for enhancing fisheries productivity. Metapenaeus macleayi (School Prawn) and Penaeus plebejus (Eastern King Prawn) are two commercially and recrea...

In south-eastern Australia, the same baited, round traps (comprising 50–57-mm mesh netting) are used to target giant mud, Scylla serrata and blue swimmer crabs, Portunus armatus in spatially separated fisheries. Both fisheries are characterised by the common, problematic discarding of undersized portunids (<85 and 65 mm carapace length; CL for S. s...

Capabilities of remotely operated vehicles (ROVs) have increased substantially in the last decade, and mini-ROV designs are now able to conduct visual research frequently conducted by snorkellers or divers in shallow marine environments. There are logistical, financial and experimental benefits of using mini-ROVs over snorkellers or divers, yet the...

The individual and cumulative effects of increasing mesh size (from 56‐ to 75‐mm stretched mesh opening) and installing three escape gaps (36 × 120 mm) in collapsible‐netted round traps were assessed to address concerns associated with excessive discarding in an Australian portunid fishery. Compared to conventional traps comprising 56‐mm mesh throu...

While post-release mortality estimates have been conducted on a range of shark species, the short-term sub-lethal effects of capture, handling and release are poorly known and have been mostly investigated in controlled conditions. In addition, the widely accepted notion that immediate post-release active swimming is an indicator of shark condition...

This chapter presents an introduction to the biogeography of southeastern Australian seagrasses, explaining the distribution and basic ecology of the 22 species that inhabit this 10,000 km stretch of coastline, from the northern limit of Queensland’s temperate zone through to Tasmania. The chapter draws on 25 years of new information (peer-reviewed...

Seagrasses are a relatively small group of marine angiosperms that have successfully colonised the oceans and includes monecious, dioecious and hermaphroditic species. They display a range of mating systems, dispersal mechanisms and recruitment strategies that have allowed them to adapt and survive within the marine environment. This includes a gen...

The response of seagrass systems to a severe disturbance provides an opportunity to quantify the degree of resilience in different meadows, and subsequently to test whether there is a genetic basis to resilience. We used existing data on levels of long-standing disturbance from poor water quality, and the responses of seagrass (Zostera muelleri) af...

Aim: Long-distance dispersal (LDD) events occur rarely but play a fundamental role in shaping species biogeography. Lying at the heart of island biogeography theory, LDD relies on unusual events to facilitate colonization of new habitats and range expansion. Despite the importance of LDD, it is inherently difficult to quantify due to the rarity of...

There is increasing uncertainty of how marine ecosystems will respond to rising temperatures. While studies have focused on the impacts of warming on individual species, knowledge of how species interactions are likely to respond is scant. The strength of even simple two-species interactions is influenced by several interacting mechanisms, each pot...

Seagrass species form important marine and estuarine habitats providing valuable ecosystem services and functions. Coastal zones that are increasingly impacted by anthropogenic development have experienced substantial declines in seagrass abundance around the world. Australia, which has some of the world’s largest seagrass meadows and is home to ov...

Seagrass meadows perform several important ecological roles in coastal areas. However, with multiple stressors threatening these aquatic plants, their current rate of decline is likely to increase, so understanding their ability to acclimate to a range of environments may be key to their survival. Light availability is critical for seagrass health,...

In a series of experiments, seeds from a temperate seagrass species, Zostera nigricaulis collected in Port Phillip Bay, Victoria, Australia were exposed to a range of salinities (20 PSU pulse/no pulse, 25 PSU, 30 PSU, 35 PSU), temperatures (13 °C, 17 °C, 22 °C), burial depths (0 cm, 1 cm, 2 cm) and site specific sediment characteristics (fine, medi...

Model selection results for mean time to germination of Z. nigricaulis seeds for the pulse, temperature and salinity experiment Model selection was based on calculated AICc values (Burnham & Anderson, 2002).

Model selection results for maximum germination of Z. nigricaulis seeds for the pulse, temperature and salinity experiment Model selection was based on calculated AICc values (Burnham & Anderson, 2002).

Model selection results for maximum germination of Z. nigricaulis seeds for the sediment type and burial depth experiment Model selection was based on calculated AICc values (Burnham & Anderson, 2002).

A priori model selection for Z. nigricaulis seed germination in the burial depth and sediment type experiment k is the number of estimable parameters in the model.

Sampling sites in Port Phillip Bay, Victoria, Australia

A priori model selection for Z. nigricaulis seed germination in the salinity and temperature experiment k is the number of estimable parameters in the model.

Statistical analysis methods for selection of analytical models

Seagrasses are ecosystem engineers that offer important habitat for a large number of species and provide a range of ecosystem services. Many seagrass ecosystems are dominated by a single species, with research showing that genotypic diversity at fine spatial scales plays an important role in maintaining a range of ecosystem functions. However, for...

Recovery from disturbance is a key element of ecosystem persistence, and recovery can be influenced by large scale regional differences and smaller local scale variations in environmental conditions. Seagrass beds are an important yet threatened nearshore habitat and recover from disturbance by regrowth, vegetative extension, and dispersive propagu...

Seagrasses are ecosystem engineers that offer important habitat for a large number of species and provide a range of ecosystem services. Many seagrass ecosystems are dominated by a single species; with research showing that genotypic diversity at fine spatial scales plays an important role in maintaining a range of ecosystem functions. However, for...

Seagrass in Port Phillip Bay is dominated by the eelgrass, Zostera nigricaulis, which occurs around the margin of the bay from the shallow subtidal zone to depths of up to 8 metres. Zostera provides crucial ecosystem services such as stabilising sediments and improving water quality, reducing coastal erosion, and increasing biological productivity...

Resilience of seagrass meadows relies on the ability of seagrass to successfully recolonise denuded areas or disperse to new areas. While seed germination and rhizome extension have been explored as modes of recovery and expansion, the contribution of seagrass viviparous propagules to meadow population dynamics has received little attention. Here,...

The southern calamary, Sepioteuthis australis, is a commercially and recreationally important inshore cephalopod endemic to southern Australia and New Zealand. Typical of other cephalopods, S. australis has a short life span, form nearshore spawning aggregations and undergo direct development. Such life history traits may restrict connectivity betw...

Seagrass meadows are among the most efficient and long-term carbon sinks on earth, but disturbances could threaten this capacity, so understanding the impacts of disturbance on carbon stored within seagrass meadows—‘blue carbon’—is of prime importance. To date, there have been no published studies on the impacts of seagrass loss on ‘blue carbon’ st...

Seagrasses are marine angiosperms with a worldwide distribution that form conspicuous beds in nearshore habitats. Despite being universally recognised as a foundation species that performs a number of important ecosystems functions (incl. sediment stabilisation, facilitation of biodiversity, nutrient cycling and carbon sequestration), global seagra...

Variability in the abundance and distribution of seagrass-associated fish assemblages was examined at different depths in a temperate bay in southern Australia. Depth differences in seagrass-associated fish assemblages are poorly known but this information is critical given that seagrass loss can occur at specific depths depending on the cause. Ove...

Shallow seagrass is an important habitat for many fish species, but little is known about fish distribution in deep seagrass or if depth affects fish distribution within patches. Using stereo video, fish distribution patterns in Port Phillip Bay, Australia, were examined in deep (3.5–6 m) and shallow (<1.5 m) areas over four months (December–March)...

Diets of the pipefish Stigmatopora nigra were analysed to determine if food availability was causing S. nigra to distribute according to habitat edge effects. Gut analysis found little difference in the diets of S. nigra at the edge and interior of seagrass patches, regardless of time of day or season. Fish diets did, however, vary with seagrass de...

1. Patch area and proximity of patch edge can influence ecological processes across patchy landscapes and may interact with each other. Different patch sizes have different amounts of core habitat, potentially affecting animal abundances at the edge and middle of patches. In this study, we tested if edge effects varied with patch size. 2. Fish were...

Seagrass beds form naturally patchy habitats with large areas of seagrass-sand interface, or edges. Fish were sampled at 3 sites in the temperate waters of Victoria, Australia, using small (0.5 m wide) push nets at 7 positions: unvegetated sand distant from the patch on the seaward side, the sand edge adjacent to the seagrass on the seaward side, t...

Loss of seagrass habitat in many parts of the world has been attributed to increases in nutrient loading to nearshore areas. The role of excess epiphyte, macroalgal or phytoplankton growth in shading of seagrass leaves and negatively affecting seagrass health is generally agreed to be a prevalent mechanism in seagrass decline worldwide. In the pres...

The relative value of temperate mangroves to fish, and the processes driving patterns of microhabitat use within this habitat, are unknown. There are 3 quickly identifiable microhabitats within temperate Australian mangroves: (1) forest (the area of mangroves with trees); (2) pneumatophores (the area directly seaward of the forest without trees but...