WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 Diversity, abundance and distribution of intertidal invertebrate species in the Ningaloo Marine Park Final Report 30 May 2011 WAMSI Project 3.2.2b 1 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 1. Executive Summary 1.1 Date 30 May 2011 1.2 Project Title & Number 3.2.2b Diversity, abundance and distribution of intertidal invertebrate species in the NMP 1.3 Project Leader Dr. Robert Black, School of Animal Biology, University of Western Australia 1.4 Project Team Prof. Michael S. Johnson, School of Animal Biology, University of Western Australia; Dr. Jane Prince, School of Animal Biology and Oceans Institute, UWA; Dr. Anne Brearley, School of Plant Biology and Oceans Institute, UWA; 1.5 Dates Covered July 2007 to May 2011 1. 6 Summary (for even shorter account see section 2.1) Aims and approach A quantitative pilot study of the composition of the benthic community of macro- invertebrates on intertidal rocky platforms was undertaken to (A) provide detailed information on variation in biodiversity along the length of the Ningaloo Marine Park and (B) determine the appropriate design of a monitoring protocol powerful enough to determine predefined levels of change. These general overall aims were in the context of the Ningaloo Marine Park Draft Management Plan of 2004, which set out a vision of maintaining the ecological values in the Park, and protecting it from adverse human impacts. The design of research and monitoring schemes must include several crucial features: (1) adequate, replicated sampling for each combination of time, location and any other controlled variable; (2) adequate, replicated sampling in areas with and without human impacts; and (3) pre-defined, quantitative criteria for what constitutes an important, continuing temporal trend or concerning difference between the sanctuary zones and impacted areas, or between 2 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 3 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 2 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 sanctuary zones some time after their establishment and their initial conditions. Even well- designed studies have to overcome the challenges of i) natural variability and patchiness at different temporal and spatial scales, and ii) natural events that overwhelm, obscure, or counteract the effects of human impacts. The Ningaloo Marine Park Draft Management Plan of 2004 seemed to fail to appreciate, comprehend, or even acknowledge the existence and magnitude of natural spatial and temporal variability against which to judge what is major rather than minor, foreseen rather than accidental loss, or prolonged rather than transient. Of course, defining the size of differences or changes that are critical (the maximum acceptable impact or effect) in any precise quantitative way will be difficult because any general definition cannot apply to all components of an ecological community, at all times, and all places within an area as large as Ningaloo Marine Park. Therefore, cases probably need individual attention in setting appropriate effect sizes indicative of concern. One view is that critical effect sizes in advance with reference to the local environment, yet the Draft Management Plan was silent about this issue. Specification of effect sizes is most often in the context of power analysis and the importance of both kinds of errors: Type I (rejecting a null hypothesis when it is true), and Type II (accepting a null hypothesis when it is false). Both require specification in studies about potential impacts that use an approach involving formal hypothesis testing, and both are relevant to managers trying to make decisions to minimize harm. However, an alternative approach, parameter estimation with confidence intervals emphasizes that the confidence intervals serve the same function as hypothesis testing and show power automatically. There is no way of avoiding careful evaluation of effect size. Sites This project examined the assemblages of macroinvertebrates at 36 sites on rocky intertidal platforms from Mildura Wreck in the north to 3 Mile in the south of Ningaloo Marine Park during 2007 to 2010, visiting 18 sites twice. There were two or more sites in seven of the 3 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 4 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 3 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 Sanctuary Zones, and one site each in two other Sanctuary Zones, totaling 22 sites. Eleven sites were close to but outside Jurabi, Bateman Bay, Pelican, Gnarraloo Bay, and 3 Mile Sanctuary Zones, and the remaining three, outside sanctuary zones, improved the geographic distribution of the sites (Table 1 - next page). Within the array of sites, and times they were sampled, there are sets of sites that are suitable for making comparisons among geographical regions in the Park, Inside and Outside of Sanctuary Zones and Inside and Outside Sanctuary Zones at different times, and for contrasting spatial with temporal variability. These comparisons are addressed for specific cases in other parts of this summary, and in detail in the research chapters. Sampling and macroinvertebrates At each site, our standard sampling scheme involved careful searches of 20 1-m2 quadrats in order to count the number of individuals of each species. Overall, the 31059 individuals in the 1744 1-m2 quadrats were allocated to 289 species of invertebrates of which most were gastropods (127 species), but included cnidarians (50), echinoderms (33), crustaceans (28), bivalves (19), chitons (12), and unusual taxa (20). Ninety-two or 32% of these species occurred as 1 individual, so additional sampling will continue to discover new species, and it is unlikely that any sampling program will ever be able to extensive enough to reveal all the species living on rocky platforms in the Park. Sites north of Yardie Creek, and sites south of Bateman Bay shared many species, but there were species found in the north only or in the southonly, indicating that future studies wishing to include a complete view of the macroinvertebrates must include sites along the length of the Park. The wider distribution of the 102 species for which we have precise identifications (mostly but not restricted to gastropods) suggests that few species are restricted the Park, and many have distributions that extend to other states. 4 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 5 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 4 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 Table 1. Sites in relation to sanctuary zones, and nature of protection. Regions (shown in Figure 1) and sites are listed in order from north to south. * indicates sanctuary zones which do not extend to shore, so the sites are not strictly in the sanctuary zone; ** indicates that the shoreline is a “Special Purpose (Shore-based Activities) Zone; *** indicates a site used to study giant clams only. (Table 1 in Research Chapter 1). Location and Region Sanctuary Zone Sites Inside Zone Sites Outside Zone Mildura Wreck Mildura Wreck West Surfers Lighthouse Bay** North Surfers South B North of northern boundary: Jurabi In 1 Jurabi Out 2 Jurabi In 2 Jurabi** Jurabi Out 3 Jurabi In 4 Jurabi Out 4 Jurabi In 3 Jurabi Out 1 Mangrove Bay C Mangrove Bay Mangrove Point Mandu South Cobble South of southern boundary: Mandu Mandu South Flat Pilgramunna D South of southern boundary: Osprey Bay Yardie Creek North Yardie Creek South North of northern boundary: Bateman Bateman Bay In Bateman Bay Out 2 Bateman Bay Out 1 Coral Bay North E Maud** Coral Bay North no map*** Coral Bay South South of southern boundary: Pelican** Elle’s In Elle’s Out Gnarraloo Bay In 2 Gnarraloo Bay Out 2 Gnarraloo Bay* Gnarraloo Bay In 1 Gnarraloo Bay Out 1 F 3 Mile North South of southern boundary: 3 Mile* 3 Mile In 2 3 Mile Out 1 3 Mile In 1 3 Mile Out 2 5 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 6 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 5 of 30 WAMSI 3.2.2b Intertidal Invertebrates 1. Executive Summary 2. Key Findings and Recommendations 4. Communication and Outputs 30 May 2011 Focal species - cowries Several of our analyses focused on particular species because of their abundance or status as a targeted or iconic species. Two potentially targeted species, the cowries Cyrpaea caputserpentis (serpent-head cowry) and C. moneta (money cowry) have wide geographic distribution, and within the Park one or both occurred at 26 sites, but in low abundance, rarely exceeding 1 m-2. Based on patterns of densities over time at these sites, recruitment and mortality of cowries varied considerably among sites, especially for C.