Ns Barrett

Global conservation outcomes depend on marine protected areas with five key features

In line with global targets agreed under the Convention on Biological Diversity, the number of marine protected areas (MPAs) is increasing rapidly, yet socio-economic benefits generated by MPAs remain difficult to predict and under debate. MPAs often fail to reach their full potential as a consequence of factors such as illegal harvesting, regulations that legally allow detrimental harvesting, or emigration of animals outside boundaries because of continuous habitat or inadequate size of reserve. Here we show that the conservation benefits of 87 MPAs investigated worldwide increase exponentially with the accumulation of five key features: no take, well enforced, old (>10 years), large (>100 km2), and isolated by deep water or sand. Using effective MPAs with four or five key features as an unfished standard, comparisons of underwater survey data from effective MPAs with predictions based on survey data from fished coasts indicate that total fish biomass has declined about two-thirds from historical baselines as a result of fishing. Effective MPAs also had twice as many large (>250 mm total length) fish species per transect, five times more large fish biomass, and fourteen times more shark biomass than fished areas. Most (59%) of the MPAs studied had only one or two key features and were not ecologically distinguishable from fished sites. Our results show that global conservation targets based on area alone will not optimize protection of marine biodiversity. More emphasis is needed on better MPA design, durable management and compliance to ensure that MPAs achieve their desired conservation value.

Effects of the declaration of marine reserves on Tasmanian reef fishes, invertebrates and plants

The reef biota in four Tasmanian marine reserves and at associated unprotected reference sites was investigated over a 6-year period following protection from fishing. The largest reserve at Maria Island (7 km coastline length) proved the most effective at achieving species conservation and resource enhancement. The number of fish, invertebrate and algal species, the densities of large fishes (>325 mm length), bastard trumpeter (Latridopsis forsteri) and rock lobsters (Jasus edwardsii), and the mean size of blue-throated wrasse (Notolabrus tetricus) and abalone (Haliotis rubra), all increased significantly within the Maria Island reserve relative to external reference sites. Increases of an order of magnitude in the biomass of rock lobsters and two orders of magnitude in the abundance of trumpeter were particularly noticeable. Small abalone declined in density within the reserve, while large abalone became more numerous. The effectiveness of marine reserves corresponded with reserve size. Changes in species richness of fishes, invertebrates or plants were not detected in any of the three smaller reserves, other than an increase in number of fish species greater than 325 mm size within the Tinderbox marine reserve (2 km reserve length). Although patterns were partly obscured by the low power of statistical tests, trends were generally evident at the Tinderbox reserve for increasing densities of large fishes and rock lobsters, and for increases in the mean size of rock lobsters, abalone and blue-throated wrasse. Most of these trends were not apparent in the reserves with small reef areas at Governor Island (1 km reserve length) and Ninepin Point (1 km length). Rock lobsters above the legal size limit nevertheless became abundant in all reserves by the end of the study while remaining rare outside. Indirect changes to reef assemblages were also detected following the declaration of the Maria Island marine reserve. Accompanying the increase in macroalgal species richness was a change in predominant plant species from Cystophora retroflexa to Ecklonia radiata. Results of this study provide the first clear evidence that shallow Tasmanian reef ecosystems are overfished, and that unfished coastal ecosystems differ substantially from those where fishing occurs. The most noticeable changes caused by fishing were the virtual elimination of net-susceptible and heavily targeted species, which may otherwise be common, plus indirect changes to algal communities. We suggest that ecosystem change associated with fishing of shallow coastal reefs may be a widespread phenomenon worldwide.

The conservation significance of estuaries: a classification of Tasmanian estuaries using ecological, physical and demographic attributes as a case study

Estuaries arguably represent the most anthropogenically-degraded habitat-type on earth, with few estuaries in temperate and tropical regions existing in a near pristine state. Conservation of estuarine biodiversity requires recognition that different estuary types are subjected to particular types and levels of human impact. To protect assemblages associated with all estuary types in Tasmania, Australia, the conservation significance of the 111 large- and moderate-size estuaries in the island state were assessed by firstly categorising estuaries into nine groups on the basis of similarities in physical attributes. These attributes were quantified using GIS maps of estuaries and their catchments and field-collected data, with separation of groups primarily reflecting presence of a seaward barrier, tidal range, salinity, estuary size and river runoff. The adequacy of the physical groups as surrogates for biological patterns was assessed by comparison with data on the distribution of 390 macrobenthic invertebrate taxa in 48 Tasmanian estuaries and 101 beach-seined fish species in 75 estuaries. Multivariate analyses indicated that six of the nine estuarine groups based on physical data were useful for categorising biological relationships between estuaries, but that three groups required modification to prove more biologically meaningful. Within each of the estuarine groups, human population, landuse and land tenure data were used to assess the level of anthropogenic disturbance to each estuary, and the estuary with least disturbance in each group assigned highest conservation significance. Recommendations have been made to create a comprehensive system of estuarine protected areas by legislating to protect species within the nine representative estuaries of highest conservation significance, plus an additional estuary with exceptional species richness. Such a system of protected areas should conserve the range of estuarine biodiversity with minimal disruption to existing estuary users.

Short term monitoring of biotic change in Tasmanian marine reserves

Fishes, large invertebrates and macroalgae inside four marine reserves and at associated external reference sites off the eastern Tasmanian coast were censused between 1992 and 1993 shortly after the declaration of the reserves. Changes in several population parameters during the first year of protection in the largest Maria Island Marine Reserve were examined using two different ANOVA designs. The densities of rock lobsters and sea urchins and the mean sizes of wrasse, leatherjackets, abalone and rock lobsters all increased within the reserve relative to outside over the first year; however, only the increases in density of sea urchins and mean abalone size were statistically significant at the 5% level. The census methodology and statistical techniques nevertheless were considered sufficiently sensitive to reveal any long term change following future censuses. A doubling in population numbers of most large fishes and invertebrates, or a 10% increase in the mean size of animals, is required to indicate that significant change has occurred.

Monitoring of Benthic Reference Sites: Using an Autonomous Underwater Vehicle

We have established an Australia-wide observation program that exhibits recent developments in autonomous underwater vehicle (AUV) systems to deliver precisely navigated time series benthic imagery at selected reference stations on Australias continental shelf. These observations are designed to help characterize changes in benthic assemblage composition and cover derived from precisely registered maps collected at regular intervals. This information will provide researchers with the baseline ecological data necessary to make quantitative inferences about the long-term effects of climate change and human activities on the benthos. Incorporating a suite of observations that capitalize on the unique capabilities of AUVs into Australias integrated marine observation system (IMOS) [1] is providing a critical link between oceanographic and benthic processes. IMOS is a nationally coordinated program designed to establish and maintain the research infrastructure required to support Australias marine science research. It has, and will maintain, a strategic focus on the impact of major boundary currents on continental shelf environments, ecosystems, and biodiversity. The IMOS AUV facility observation program is designed to generate physical and biological observations of benthic variables that cannot be cost effectively obtained by other means.

Benthic macrofauna in Tasmanian estuaries: scales of distribution and relationships with environmental variables

Abstract Information on the distribution of species richness, faunal density, biomass and estimated productivity of benthic invertebrates in Tasmanian estuaries was quantified at a variety of spatial and temporal scales to assess general hypothesis relating community metrics to such environmental variables as salinity, seagrass biomass and sediment particle size. An associated aim was to assess appropriate scales of investigation for soft-sediment biota distributed in estuaries, including whether patterns identified at individual sites, estuaries, tidal levels or times are likely to have more general relevance. Faunal biomass and productivity varied principally at between-estuary (10 to 1000 km) and replicate-sample (1 m) scales, indicating that these two community metrics were largely responding to estuary-wide effects, such as nutrient loading, and to microhabitat features, rather than to locality characteristics at intermediate scales such as salinity, anoxia or sediment particle size. By contrast, faunal density showed greater response to tidal height (1 to 100 m) and to factors distributed at the locality scale within estuary (10 km) than to factors between estuary. Both faunal density and species richness in estuaries declined over three- and fivefold ranges down the shore from high water mark to the shallow sublittoral, while estimated productivity and biomass showed highest overall levels at low water mark. The greatest component of variance in species richness was associated with tidal height, with variance then distributed approximately evenly between other spatial scales examined. At the low-tide and shallow subtidal levels, species richness, faunal biomass and estimated productivity were all highly correlated with salinity and biomass of macrophytes, whereas faunal density was highly correlated with biomass of macrophytes only. Relationships between environmental and biological variables examined were poorly defined at high tidal levels. Seasonal plus interannual variance was much lower than spatial variance—a clear indication that sampling effort in studies would generally be better directed across a range of localities than for a single locality to be repeatedly investigated over time.

Short- and Long-term Movement Patterns of Six Temperate Reef Fishes (Families Labridae and Monacanthidae)

Abstract. Movement patterns were studied on a 1-ha isolated reef surrounding Arch Rock in southern Tasmania. Short-term movements were identified from diver observations, and interpretation of long-term movements involved multiple recaptures of tagged individuals. Visual observations indicated that the sex-changing labrids Notolabrus tetricus, Pictilabrus laticlavius and Pseudolabrus psittaculus were all site-attached, with females having overlapping home ranges and males being territorial. In the non-sex-changing labrid Notolabrus fucicola and in the monacanthids Penicipelta vittiger and Meuschenia australis, there was no evidence of territorial behaviour and I-h movements were in excess of the scale of the study. The long-term results indicated that all species were permanent reef residents, with most individuals of all species except M. australis always being recaptured within a home range of 100 m X 25 m or less. Only 15% of individuals of M. australis were always recaptured within this range category. The natural habitat boundary of open sand between the Arch Rock reef and adjacent reefs appeared to be an effective deterrent to emigration. The use of natural boundaries should be an important consideration in the design of marine reserves where the aim is to minimize the loss of protected species to adjacent fished areas.

Thermal biases and vulnerability to warming in the world’s marine fauna

A critical assumption underlying projections of biodiversity change associated with global warming is that ecological communities comprise balanced mixes of warm-affinity and cool-affinity species which, on average, approximate local environmental temperatures. Nevertheless, here we find that most shallow water marine species occupy broad thermal distributions that are aggregated in either temperate or tropical realms. These distributional trends result in ocean-scale spatial thermal biases, where communities are dominated by species with warmer or cooler affinity than local environmental temperatures. We use community-level thermal deviations from local temperatures as a form of sensitivity to warming, and combine these with projected ocean warming data to predict warming-related loss of species from present-day communities over the next century. Large changes in local species composition appear likely, and proximity to thermal limits, as inferred from present-day species’ distributional ranges, outweighs spatial variation in warming rates in contributing to predicted rates of local species loss.

A Standardised Vocabulary for Identifying Benthic Biota and Substrata from Underwater Imagery: The CATAMI Classification Scheme

Imagery collected by still and video cameras is an increasingly important tool for minimal impact, repeatable observations in the marine environment. Data generated from imagery includes identification, annotation and quantification of biological subjects and environmental features within an image. To be long-lived and useful beyond their project-specific initial purpose, and to maximize their utility across studies and disciplines, marine imagery data should use a standardised vocabulary of defined terms. This would enable the compilation of regional, national and/or global data sets from multiple sources, contributing to broad-scale management studies and development of automated annotation algorithms. The classification scheme developed under the Collaborative and Automated Tools for Analysis of Marine Imagery (CATAMI) project provides such a vocabulary. The CATAMI classification scheme introduces Australian-wide acknowledged, standardised terminology for annotating benthic substrates and biota in marine imagery. It combines coarse-level taxonomy and morphology, and is a flexible, hierarchical classification that bridges the gap between habitat/biotope characterisation and taxonomy, acknowledging limitations when describing biological taxa through imagery. It is fully described, documented, and maintained through curated online databases, and can be applied across benthic image collection methods, annotation platforms and scoring methods. Following release in 2013, the CATAMI classification scheme was taken up by a wide variety of users, including government, academia and industry. This rapid acceptance highlights the scheme’s utility and the potential to facilitate broad-scale multidisciplinary studies of marine ecosystems when applied globally. Here we present the CATAMI classification scheme, describe its conception and features, and discuss its utility and the opportunities as well as challenges arising from its use.

AUV Benthic Habitat Mapping in South Eastern Tasmania

This paper describes a two week deployment of the Autonomous Underwater Vehicle (AUV) Sirius on the Tasman Peninsula in SE Tasmania and in the Huon Marine Protected Area (MPA) to the South West of Hobart. The objective of the deployments described in this work were to document biological assemblages associated with rocky reef systems in shelf waters beyond normal diving depths. At each location, multiple reefs were surveyed at a range of depths from approximately 50 m to 100 m depth.We illustrate how the AUV based imaging complements benthic habitat assessments to be made based on the ship-borne swath bathymetry.Over the course of the 10 days of operation, 19 dives were undertaken with the AUV covering in excess of 70 linear kilometers of survey and returning nearly 160,000 geo-referenced high resolution stereo image pairs. These are now being analysed to describe the distribution of benthic habitats in more detail.