Integrating Indigenous knowledge and survey techniques to develop a baseline for dugong (Dugong dugon) management in the Kimberley Peter Bayliss, Marlee Hutton & project team (CSIRO, Indigenous rangers & WA Marine Parks) WAMSI Kimberley Research Node
Overview of North Kimberley WAMSI dugong project o Talk outline Indigenous Knowledge & research partnerships o Mapping baseline dugong distribution & abundance using aerial survey (2015) o South Kimberley aerial survey extension(may 2017) Movement study using satellite tags initial results & long-term plan How can this research help manage saltwater country? - Population Monitoring - Dugong movement - Habitat (Seagrass)
The Kimberley dugong project In partnership with North Kimberley rangers groups to support their Healthy Country Plans, IPA management and present & future co-managed marine parks Balanggarra Wunambal Gaambera Dambimangari Bardi Jawi (Uunguu)
Background Dugongs are listed as vulnerable globally and northern Australia is home to the largest remaining healthy populations. There was limited survey information in the Kimberley. Culturally significant - deep Indigenous connection & knowledge. Currently limited human-induced threats to dugongs in the Kimberley. However - development & people pressures will increase.
Project aims Develop long-term research partnerships with the Balanggarra, Wunambal Gaambera Dambimangari & Bardi Jawi Kimberley Native Title and associated ranger groups. Integrate Indigenous & scientific knowledge of dugongs to work out how best to monitor and manage populations in future. Determine regional-scale patterns of dugong distribution & abundance using aerial survey methods, & in partnership with Indigenous rangers (i.e. establish a baseline to assess future changes & provide essential training). Initiate a long-term dugong movement study to better understand habitat use in relation to seagrass condition & other factors.
Dugongs & seagrass Where you find seagrass you ll find dugongs Seagrass found in shallow coastal waters generally < 20m depth
First-pass seagrass map of Kimberley coastal waters Landsat 8 mosaic Kimberley coastal waters Preliminary benthic vegetation map (un-validated) Janet Anstee CSIRO 2015
Cultural maps of dugong & marine turtle sites in the North Kimberley (from published Health Country Plans)
Cultural maps of dugongs were combined with scientific data (seagrass & 20m bathymetry maps) to design a more efficient aerial survey Transect spacing 5 or 10 km. More survey transects/effort located over cultural sites, predicted seagrass areas & in shallow waters (<20m). Survey blocks & East-West transects Cost savings ~ 35% less survey time.
Aerial survey training course 4-day package delivered on country (hosted by Uunguu rangers)
Flying east-west sample transects / survey block; tandem observers both sides plane (double counts); observations recorded continuously onto audio files Tascam 6-track audio sound recording gear with transect elapse time synchronised with a GPS track log - gives approx. GPS position of observations Tascam recorder Tandem observers Port-side Aviation headset East-west transect Plane cabin GPS Tracklog
Dugongs & snubfin dolphins can be confused ID issue during NT surveys & in some areas in Kimberley where two species co-occur at high densities Snubfin dolphins large tight groups Dugongs dispersed individuals hang out together, with close mother-calf groups
Other marine mammals, turtles, manta rays & sea snakes Bottlenose Dolphins False killer whale Manta Rays Sea snakes Humpback Whales Australian Humpback Dolphins Turtles Spinner dolphins
Dugong sightings WAMSI (2015) + Woodside (2009)
RESULTS Estimates of minimum number & relative density of dugongs in the N Kimberley after correction for visibility bias using a modified version of the Pollock et al. (2006) method & water depth models of Hagihara et al. (2014) (i.e. for the proportion of dugongs missed on the surface & under the water) BLOCK Number Standard Error (SE) % SE Density (nos.km 2 ) 3 1,758 452 25.7 0.22 0.06 4 2,119 444 21.0 0.28 0.06 5 2,926 792 27.1 0.55 0.15 6 3,682 929 25.2 0.69 0.17 7 636 170 26.7 0.31 0.08 8 541 112 20.7 0.26 0.05 9 177 43 24.0 0.07 0.02 TOTAL 11,839 (+ 1,391) 11.8 0.36 (+ 0.04) SE
Dugong abundance hotspots combining WAMSI (2015) + Woodside (2009)aerial survey data (high resolution Kernel smoothing)
Aerial survey coverage of dugongs in Australia & Torres Strait Remaining gap was Broome to Port Hedland surveyed in May 2017 North Kimberley WAMSI & Woodside Dampier P & Roebuck Bay surveys NT Torres Strait GoC GAP Roebuck Bay & 80 Mile Beach Shark Bay Ningaloo - Exmouth GBR SEQ Moreton Bay
Dugong project wrap-up Kimberley - October 2017 DUGONG abundance hotspots mapped by Kernel smoothing of all sighting data (on- and off-transects) across the 5-km aerial survey grid.
DUGONGS. Distribution of dugong sightings (on- and off-transects) by all observers during surveys in the Kimberley region.
Combined North and South Kimberley Surveys DUGONG - Abundance hotspots. All sighting data were used to map smoothed densities across A5-km aerial survey grid. Within the North and South Kimberley survey areas red colours have the highest numbers and blue colours the lowest, with a colour-abundance range in between (orange, yellow & grey).
Bayesian likelihood method to combine Indigenous Knowledge with scientific survey data to identify important dugong areas Major constraint to ID of important dugong areas is the inherent uncertainties & measurement errors associated with observational data collected over short time frames. Bayesian approach used to integrate IK accumulated over millennial time-scales (location hunting sites) with instantaneous slices of scientific survey data (sea grass map, aerial survey data). Venn diagram - joint intersection (Pj) when all sources of dugong knowledge occur together (& other combos) Calculate spatially-explicit joint probabilities across a 5 km aerial survey grid.
Individual probabilities of dugong occurrence for Indigenous Knowledge (hunting sites), seagrass extent (% cover) and re-scaled aerial survey abundance data (across a 5 km aerial survey grid) Indigenous Knowledge (cultural maps from HCPs) Preliminary seagrass map via remote sensing Sept. 2015 Dugong aerial survey Note: all maps & data can be continuously updated with new & improved knowledge = adaptive management & monitoring
Dugong movements & diving behaviour Trial satellite tagging study in North Kimberley with Bardi Jawi & Dambimangari rangers August 2016 ARGOS satellite WAMSI Dugong KMRP project Conference wrap-up Kimberley November - October 2017 2017
Capture & tagging dugongs Rodeo capture method with chase & process boats, spotter plane. Satellite tags - GPS & dive data obtained every 6 hrs through ARGOS satellite link. Deployed 5/8 tags, retrieved 3 that detached. Harness stays attached for 6 months max until zinc bolt corrodes, or the weak link breaks if tether becomes caught in mangrove/coral.
Trajectories of tagged dugongs over variable tracking intervals between August 2016 and February 2017. (a) Adult female (F1) tagged at Talbot Bay (HFMP - Dambimangari sea country), and (b) young adult males (M1-M4) tagged north of Pender Bay on Dampier Peninsula (Bardi Jawi sea country).
Young or sub-adult male M4 Pender Bay Aug 2016 78 days Key findings: dugongs capable of moving very large distances over short periods of time awesome. They cross jurisdictionalgovernance boundaries so are a shared cultural resource & a joint responsibility across Native Title groups & all levels of government. Local & regional management scales are important - need BOTH approaches to manage dugongs. 20 km 26
Research, management & monitoring of dugongs Where to next? Population Monitoring Movement Monitoring Habitat Monitoring
Kimberley Node KISSP presentation Dugongs 1.2.5 Sept 2016 Some ideas to monitor dugong populations in the Kimberley using a range of methods to fit different needs 1. Fixed-wing aerial survey methods: Great for mapping relative distribution & abundance over large geographic regions. Because of costs funding comes around ~ 15-20 y if you re lucky. NO one size fits all solution to monitoring dugong abundance, especially in small local areas or where terrain is unsuitable (e.g. Horizontal Falls Marine Park). 2. Use other methods, or combination methods, for regular small area surveys that are more suitable & sustainable for local communities: Small-boat surveys at representative & high priority Kimberley sites, say 2 sites / sea country. Helicopters or drones provide better counts (less confusion with snubfins, more animals detected over a range of seasonal conditions).
Kimberley Node KISSP presentation Dugongs 1.2.5 Sept 2016 Some ideas to monitor dugong populations in the Kimberley using a range of methods to fit different needs 3. Major challenge of broad-scale aerial survey method has been estimating the absolute abundance of dugongs, if it s actually required for management (& is a debatable objective). Investigate potential of Close-Kin genetic methods to complement aerial & boat-based surveys, & to obtain other demographic data (e.g. mortality, recruitment & dispersal rates). Data derived from tissue samples collected over time (e.g. from hunted samples, targeted samples)
Movement study using acoustic receivers & tags Battery life tags ~ 10yrs, receivers 1 yr, need to be anchored as very big tides, 800m array separation Acoustic receiver array design ~ 1 km apart Unsuitable for dugongs in study area at the time (August) as satellite-tagged animals moved large distances in relatively short periods of time ( drifting home ranges ). Move >> than the array coverage of 6 x 3 km. Ideal for Roebuck Bay
Local Scale: Seagrass Watch type surveys used to monitor condition of dugong habitat where few dugongs (e.g. Mary Island Uunguu rangers) Large Scale: Seagrass Mapping of Kimberley region (e.g Aerial and satellite images or field surveys) % cover by sea grass species
Kimberley Node KISSP presentation Dugongs 1.2.5 Sept 2016 Thanks to many people Traditional Owners from Balanggarra, Wunambal Gaamera, Dambimangari, Bardi Jawi. The Kimberley Land Council and Yawuru (Dean Mathew) & Karajarri (Sam Bailey). Thomas Grounds/Tom Nagle, Tom Vigilante, Jarrad Holmes/James Mansfield, Daniel Oades/Phil McCarthy, Tom Holyoake/Frank Weisenberger (KLC) Project Advisory Committee for North Kimberley dugong project. DBCA marine parks & WAMSI partners (Stuart Field & Kelly Waples; Leah Pearson & Chris Nutt DBCA Broome). Emma Woodward, TJ Lawson, Rich Pillans, Mat Vanderklift, Andy Steven (CSIRO); Glenn Dunshea, Daniella Hanf & David Waayers (EMS Pty Ltd); Richard Campbell (NT NLC).