This is a ppt that was used in my confirmation for candidature. It describes how I will use stable isotope and fatty acid analysis to determine what estuarine sharks and rays eat and which areas of the South Alligator River, (NT, Aus) they utilise. This will then inform environmental managers of which areas are critical to the survival of these species.
3. Ecological Niche
Describe abiotic and biotic variables that affect an organism and how
that organism then affects those same variables (Chase & Leibold 2003; Hirzel & Le
Lay 2008; Hutchinson 1957; McInerny & Etienne 2012).
O
H
N
C
N
Habitat
4. Fundamental and Realized Niches
2 ways the niche is described
Fundamental
Why are penguins
absent?
Niche Width
Realized
5. Significance of Elasmobranchs
Ecologically
Apex & meso predators - extensive role in
ecosystems
(McDavitt, 1996)
Based on Pen Ts’ao
Kang Mu
(pharmacopeia)
Culturally
Many coastal societies have stories /legends
E.g. PNG, Australia – Yolngu & Angurugu,
Africa, China, Borneo, even Europe/UK
Economically
Artist: Nekingaba
Maminyamanja, Date: c.
1980. McDavitt (2005)
Fishing, curios, tourism, herbal medicine,
food
Li Livres dou Tresor codex,
facsimile di M. Moleiro: fol. 45v
6. Importance of Predators
‘Top down’ effect in food webs
Reductions - serious ramifications for ecosystems (Estes et
al. 2011)
E.g. Chesapeake Bay, USA scallop industry decimated
(Myers et al. 2007)
Apex predators
(Makos,
Hammerheads
Whalers) eat rays
Over fishing + habitat degradation
Meso predator –
Cownose Ray eats
Oysters
Population explosion
Oyster bed healthy
Decimated bivalves
7. Elasmobranchs (sharks and rays) –
Predators at risk.
Indo- Australian at Risk
North Central American
Species at Risk
Concern
14%
60% not
at risk
Concern
40%
86% not
at risk
Why at Risk?
Anthropogenic
influences e.g. fishing
& habitat destruction
(Cavanagh et al. 2003; Myers et
al. 2007)
(Baum & Worm 2009; Dulvy et al.
2008; Kyne et al. 2012; Myers et
al. 2007; White & Kyne 2010).
Why Important?
• Key roles in marine
ecosystems &
communities
• Influence species
diversity,
population sizes &
prey (Cortés 1999; Heithaus et
al. 2008)
8.
9. Trophic Niche - Diet
•
Assists in determining
effect of species loss
•
Bearhop et al. (2004) conceptual framework
• 3 broad types of
consumers:
• “Specialists” - narrow
range of prey
• “Generalists”
•
Type A - wide range of
prey
•
Type B generalists –
individuals eat specific
prey from wide range of
items
Figure 1:
Representation of the differences between feeding types in consumer populations. (Bearhop et al.
2004)
10. Spatial Niche – Space Usage
• Is influenced by:
• species dispersal
• conducive environmental
conditions & resources for
survival
• reproduction
• interspecific interactions
(predators, pathogens)
• Habitat specialists - more at risk
(Arakaki & Tokeshi 2010; Hirzel & Le Lay 2008; Soberón 2007; Pulliam 2002)
11.
12. Indigenous Communities & Euryhaline
Elasmobranchs
85% of coastal and estuarine environments
Norma Joshua in Normand 2004
Knowledge of NT ecosystems extensive &
historic
Are culturally (totemic) & economically
significant
Australia’s indigenous harvest – preliminary
estimates only
Extent, impacts & data lacking.
(Ens 2012; Altman, Buchanan & Larsen 2007; McDavitt 1996, 2005;
Waddy 1988; Heath 1980, 1988)
13. http://cheekydancers
.wordpress.
Com/original-dance-history/
Indigenous Ecological
Knowledge (IEK)
http://jobs.nsw.gov.au/
Accumulated knowledge of species based on oral
histories & information transferred through past
generations (TEK or IEK)
Interconnected science and cultural knowledge
systems
Observations from 1000’s of years of living in an
environment can be applied to western niche
concept – particularly spatial niche
(Berkes 2008; Horstmann & Wightmann 2001)
http://glucoensuremd.com/2/aboriginal-men-hunting
http://www.janesoceania.com/australian_aboriginal_anthropology/index1.htm
14. Examples of IEK
Cyclic patterns
Caribou,
Canada
(Ferguson, Williamson &
Messier 1998),
Medicinal
plants in Mexico
(Yucatán) (Hunn
2001; Nabhan 2001)
Fire management
techniques (Russell-
Habitat preferences,
Puerto Rico (García-Quijano 2007)
Smith, Whitehead & Cooke
2009
Co-management –
Great Barrier Reef
(George, Innes & Ross 2004;
Nursey-Bray 2009)
15. “Two way” learning
• Indigenous & non-Indigenous
people share knowledge
• Contribute historical &
observational data (Ens, 2012)
Australian studies using this method:
The habitat, diet & behaviour of
Rock-Wallabies (Telfer & Garde 2006)
Reptile behaviour, movement &
distribution (Baker 1992)
16. ‘Two Way Tool Box’
How important is the
freshwater
environment in the
ecology of euryhaline
elasmobranchs ?
IEK
Interviews
Cultural Mapping
Understanding:
Trophic Niche
&
Spatial Niche
Stable Isotope Analysis
Acoustic Tagging
Lipid Analysis
17.
18. Euryhaline Elasmobranchs
Tolerate a range of salinities
Highly specialised life histories
Global decline due to:
Rapid human population growth
Disturbance (Compagno 2002; Compagno & Cook 1995)
Rare, threatened & ‘data-poor’
Smalltooth Sawfish, Pristis
pectinata USA
19. Why study spatial & trophic ecology in
NT?
Legal fisheries 10 cause of sawfish decline
NT riverine environment “near pristine”
Critical habitats / key prey species
Accurate management plans
Bull Shark
Carcharhinus leucas
Speartooth Shark
Range of species
Glyphis glyphis
Freshwater
Sawfish Pristis
pristis
Northern River Shark
Glyphis garricki
Dwarf Sawfish
Pristis clavata
Freshwater
Whipray Himantura dalyensis
20. NT Rivers
Massive tidal ranges, increasing salinity (dry season) &
extensive mangrove forests
Remote & difficult to access
“ Near Pristine” (more data needed on impacts)
Feral animals, weeds, development, agriculture & mining
International strongholds for aquatic biodiversity
21.
22. Trophic niche of euryhaline
elasmobranchs
Diet from X- rays & gut content analysis
Detrital
matter
G. garricki
Other
P. pristis
P. pristis
G. garricki
P. pristis
P. clavata
C. leucas
C. leucas
C. leucas
C. leucas
C. leucas
• From Stable Isotope Analysis:
• Pilot study: dietary & habitat overlap within sawfish P.
pristis and P. clavata different from A. cuspidata.
• USA C. leucas: Evidence of Type B generalists with
individual specialization
23. Spatial niche of euryhaline
elasmobranchs.
Movement & Distribution Studies
Distribution: - rivers, estuaries & coastal areas of
northern Australia
P. pristis - WA acoustic tagging, conventional tags,
some genetic work
C. leucas - genetic studies , habitat partitioning &
directly from acoustic tagging in South QLD & USA
Tillet (2011) dissertation NT
Only C. leucas study in ‘near pristine’ river
systems
(Peverell 2005; Pillans et al. 2009; Stobutzki et al. 2002; Thorburn et al. 2008; Thorburn
et al. 2003; Thorburn & Rowland 2008; Whitty et al. 2009).
24. IEK knowledge of Elasmobranchs in
NT
Limited IEK on shark & ray species – particularly
in NT
Sea country people have deep totemic connections
(e.g. Ngukurr, Groote) – more knowledge exists?
Intact cultural landscapes of the NT
Potentially inform management of river &
estuaries
(McDavitt 1996, 2005; Waddy 1988)
25.
26. Aims
1. To determine the inter- and intra-specific trophic
niches of euryhaline elasmobranchs in NT tropical
aquatic ecosystems.
2. To determine the spatial niche (i.e. movement and
habitat use) of a model euryhaline elasmobranch
species (the bull shark, C. leucas).
3. To record indigenous knowledge & the ecological &
cultural role of euryhaline elasmobranch species.
27. To determine the inter- and intra-specific trophic niches of
euryhaline elasmobranchs in NT tropical aquatic ecosystems.
Null Hypotheses:
i.
ii.
Different species (e.g. P. pristis, C. leucas, G. glyphis and G. garricki)
will be dietary specialists and have distinct partitions from each
other.
There will be no intra-specific dietary specialization within species.
28. Trophic Methods
Fatty acid (FA) & stable isotope (SIA) analysis
Fish caught using: Hook and line (barbs
removed), gill nets 4 -7 inch, demersal (bottomset) 20 hooks & Cast nets
Primary producers & invertebrates also sampled
Muscle tissue - longer turn over (more effective
for diet) & if any unforseen mortalities - liver
tissue
20 -30 individuals
Potential prey collected for SIA & fatty acids – 5
representatives
Caudal Peduncle –
site of biopsy
30. Lipid Analysis
Marine algae
synthesize lipids
Vertebrates ingest lipids
from food chain
Cell membranes & adipose tissue
significantly influenced by
consumption (Sargent, Tocher & Bell 2002).
31. Trophic Analysis – Mixing Models
Determine proportions of food to reconstruct diet
Inclusion of fatty acids refines model
Important to exclude confounding influences –
urea, lipids
Trophic position estimate formula
TP elasmobranch = (δ15N elasmobranch − δ15N baseline
organism)(δ15N)−1 + TP baseline organism
32. To determine the spatial niche (i.e. movement and habitat
use) of a model euryhaline elasmobranch species (the bull
shark, C. leucas)
Null Hypothesis: C. leucas will be a habitat generalist and will not display
habitat specialization.
33. Defining spatial niche using
acoustic tagging
• 30 C. leucas –tagged with
acoustic transmitter in
abdominal cavity
• “ping” is received by an
acoustic receiver
• 33 acoustic receivers (NERP) South Alligator River
• physical parameters
34. South Alligator
River
Location of acoustic
receivers
= Acoustic Receiver
Arnhem Highway
Yellow Waters
Map from Richard Pillans - CSIRO
35. Analysis of Spatial Data
Range testing acoustic receivers
Extent & timing of movement
Analyse correlations between movement & habitat
type, salinity, seasons, lunar cycles, tides
Find habitat preference & possible influences to that
preference
36. To record indigenous knowledge & the ecological & cultural role
of euryhaline elasmobranch species.
37. On preliminary visit people were willing to share
knowledge of sightings of Sawfish and potential
habitat.
38. Study
Background
of
community
Implement
tools in
communal
areas
Reflect & adjust
tools on
recommendations
IEK Methods – Participatory Action
Analyse data
Research (PAR)
determine whom
Determine
stakeholders,
format
plan, request
permissions
Input from
elders, Yugul Mangi
Rangers & community
to interview
further
Format semi –
structured
questions
Develop brief
survey tool
consisting of
timelines and
maps
Write up
including report
for community
Analyse
data /
draft
Carry out
interviews
(Chevalier & Buckles, 2012; Baum, MacDougall, Smith 2006)
39. Semi-Structured
Interviews
Open questions - encourage discussion &
range of topics
Interviews ‘on country’ (if possible),
approx. 1 hour, with refreshments
Interviewees dependant on number of
knowledge holders
Electronically recorded
Ngukurr Language Centre
Payment offered to interviewees
(Grenier 1998; Huntington 2000; Weiss, Hamann & Marsh 2012)
40. Yugul Mangi Land & Sea Rangers as
research assistants
• Potentially collect samples from
community
• Safety on country (e.g. river and
road hazards)
• Help identify key people with
cultural rights to share knowledge
• Relationship building within
community
43. Significant Partners & Ethics
NAMRA scholarship $15 000
operation costs / year
NERP Marine Biodiversity Hub
(CDU, NT Fisheries) will
contribute: field support,
transport, tissue collection and the
use of acoustic receivers.
Co- authorship offered to
significant contributors ie The
Yugul Mangi Land and Sea Rangers
publication they will be listed as
co-authors.
Stable isotope analysis Australian
Institute of Marine Science (AIMS)
at the Arafura Timor Research
Facility (ATRF)
Fatty Acids will be analyzed with
assistance from Dr. Peter Nichols
of CSIRO Hobart.
NLC research permit: In Progress
S17 NT fisheries approved:
S17/3268
Animal ethics approved: A12016
Human ethics approved: H12117
44. Acknowledgements
Thankyou to everyone who has provided advice, assistance &
support!
NAMRA
Supervisors
NERP – Peter Kyne Collection of samples & acoustic study
ATRF / AIMS
CSIRO – Peter Nichols
NT Fisheries (Grant Johnson)
Yugul Mangi Rangers
Ngukurr Community
Robertson Family - Ngukurr
Notas del editor
The ocean is included in the fundamental etc just cant see here~Facilitation both species benefiting from the interaction
Yongulu - sleeping speared by another clan memember and then chased the person up river creating the land scape – don’t annoy a shark clan member!! Sawfish Considered supernatural beings – creating natural and social order in many countries PNG –spirit controls the fecundity of fish, if killed – destructive storms (McDavitt, 1996)Groote Eyelandt –cut through central hill to Angurrkwurrikba Salt Lake followed by stingrays (all of which, including the waters are totems) (Waddy, 1982) Whaler Sharks Yongulu believe that the ancestral whale shark carved the river and landscape whilst enragedshark-based ecotourism contributed an estimated .30% towards the Maldives GDP (Ndurya & Kihara, 2009). $3,300 per year, and over $35,000 per year at the most popular dive sites. Grey reef sharkUS$800 million to the Bahamian economy (Cline, 2008). Sesasonal cues
Dietary differences in individuals may occur due to ontogenetic or gender differences, or availability of food in their habitat
Organisms movement results in change of physical space affecting assemblages, distribution & interspecific competition .Species can share or be aggressive – at an inter or intraspecific Species requirements for space can be specific such as “habitat specialists” that require specific environmental conditions compared to “habitat generalists” that can tolerate a range of conditions . Habitat specialists are generally less abundant and may have a greater extinction risk due to disturbance. This has been evident in fish e.g. , arthropods e.g. and primates e.g. . A mobile species may require several habitat sites that they move between to find; mates, breeding habitats, avoid predators and find prey. In doing so they influence community dynamics
usage of both the river and sea particularly significant, Act of fishing allows for the transmission of knowledge to the next generation
Increasingly, around the world the use of multiple knowledge systems have been advocated in management planning and the understanding of species and ecosystems Some Indigenous Australians have an accumulated knowledge of species based on oral histories and information transferred through past generations (sometimes referred to as Traditional or Indigenous Ecological Knowledge). Indigenous Ecological Knowledge (IEK) refers to the interconnected science and cultural knowledge systems that Indigenous people have acquired through millennia of observation, experimentation and teaching that has led to an accumulated body of knowledge .
Abundance and distribution - medicinal plants in Mexico Cyclic patterns – Caribou in Canada Habitat preferences – fish in Puerto Rico Dietary requirements of a range of species.Fire management techniques Dugongs and turtles , and the co-management of the Great Barrier Reef .
Research with theAnangu (Indigenous people of central Australia)
E.g. Smalltooth Sawfish, Pristis pectinata USA (Simpfendorfer, Wiley & Yeiser 2010), Freshwater Sawfish Pristis pristis in Guinea (Robillard & Séret 2006), Africa and South East Asia (Compagno 2002; Siriraksophon 2012)
illegal foreign fishing, particularly in Gulf of Carpentaria so that trophic levels and feeding specializations can be determined.
Comparatively compared to AustraliaAs such the river ecosystems of the NT are ideal to investigate euryhaline elasmobranchs
Numbers low , 3 ,5 & 10
(excepting McDavitt) Totem a representation or related to a natural object
Sampling integratedLive V muscle can give indication of change or variation in dietThe muscle will be collected in the caudal peduncle region
Useful as tracers as organmiscans can modify and lengthen but this is limited as it goes up the food chainLipids are generally taken up in their basic formFat storedMarine algae are essesntially the only organism capaple of producing Long Chain Polyunsturated FA
where δ15Nbaseline organism and TPbaseline organism are the δ15N value and predicted TP for a low trophic level or baseline organism in the ecosystem, normally a sessile organ- ism such as a clam or mussel and 15N is the DTDF (Post, 2002 Diet discrimination factors
Site attachment or driven by enviromental variables
Gate – time, date unique code120 sec nominal delay Bewary of false codes – one detection probably not right
noise to avoid interferenceRange test – hang transmitter off boat in approbriate location of where the fish would swim & left in place to test the number of transmissions
Consultation process is Iterative based on continuous feedback from community
Informed prior consent
These relationships are fundamental to any undertaking in Indigenous communities .
