New Publication: Applying the Multistate Capture-recapture Robust Design to characterize metapopulation structure

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We are pleased to announce the following publication in Methods in Ecology and Evolution:

Applying the Multistate Capture-recapture Robust Design to characterize metapopulation structure

Full citation: Chabanne, D.B.H., Pollock, K.H., Finn, H. and Bejder, L. (2017). Applying the Multistate Capture-recapture Robust Design to characterize metapopulation structure Methods in Ecology and Evolution. DOI: 10.1111/2041-210X.12792

 

Abstract:

  1. Population structure must be considered when developing mark-recapture (MR) study designs as the sampling of individuals from multiple populations (or subpopulations) may increase heterogeneity in individual capture probability. Conversely, the use of an appropriate MR study design which accommodates heterogeneity associated with capture-occasion varying covariates due to animals moving between ‘states’ (i.e. geographic sites) can provide insight into how animals are distributed in a particular environment and the status and connectivity of subpopulations (Figure 1: The Multistate Closed Robust Design approach).
  2. The Multistate Closed Robust Design (MSCRD) was chosen to investigate: 1) the demographic parameters of Indo-Pacific bottlenose dolphins (Tursiops aduncus) subpopulations in coastal and estuarine waters of Perth, Western Australia; and 2) how they are related to each other in a metapopulation. Using four years of year-round photo-identification surveys across three geographic sites (Figure 2), we accounted for heterogeneity of capture probability based on how individuals distributed themselves across geographic sites and characterized the status of subpopulations based on their abundance, survival and interconnection.
  3. MSCRD models highlighted high heterogeneity in capture probabilities and demographic parameters between sites. High capture probabilities, high survival and constant abundances described a subpopulation with high fidelity in an estuary. In contrast, low captures, permanent and temporary emigration and fluctuating abundances suggested transient use and low fidelity in an open coastline site (Figure 3: Abundance estimates).
  4. Estimates of transition probabilities also varied between sites, with estuarine dolphins visiting sheltered coastal embayments more regularly than coastal dolphins visited the estuary, highlighting some dynamics within the metapopulation.
  5. Synthesis and applications. To date, bottlenose dolphin studies using mark-recapture approach have focused on investigating single subpopulations. Here, in a heterogeneous coastal-estuarine environment, we demonstrated that spatially structured bottlenose dolphin subpopulations contained distinct suites of individuals and differed in size, demographics and connectivity. Such insights into the dynamics of a metapopulation can assist in local-scale species conservation. The MSCRD approach is applicable to species/populations consisting of recognizable individuals and is particularly useful for characterizing wildlife subpopulations that vary in their vulnerability to human activities, climate change or invasive species.

 

Figure1 Figure 1. Traditional Closed Robust Design (CRD) versus Multistate Closed Robust Design (MSCRD) approaches to characterize metapopulation structure and dynamics through demographic parameters. Both approaches allow estimation of abundance (N), apparent survival rate (φ) and emigration and immigration [solid arrows] either time varying (t, t+1, t+2, etc) or constant. Additionally, MSCRD models estimate any transition probabilities ψ [dashed arrows] between subpopulations associated with states (i.e. geographic sites)

 

Figure2

Figure 2. Map of the metropolitan waters of Perth, Western Australia, showing the systematic survey routes within each site: the estuary SCR – Swan Canning Riverpark and the coastal sites including the semi-enclosed embayment CS/OA – Cockburn Sound/Owen Anchorage and the open coastline GR – Gage Roads. Within the coastal sites, surveys were conducted by rotating between three pre-defined transect routes (full, long dash and short dash lines) to maximize the coverage.

 

Figure3_CEDP_Delphine

Figure 3. Seasonal estimated abundances ( total ± 95% confidence intervals) for three sites (red: estuary SCR – Swan Canning Riverpark; yellow: semi-enclosed embayment CS/OA – Cockburn Sound/Owen Anchorage; and purple: open coastline GR – Gage Roads). Lines between data points have been used for illustrative purposes only; continuity of values is not implied. Note: The figure was modified to only show the results of Scenario 1 (three sites).

 

Download the paper: The article can be downloaded HERE, or alternatively, please email Delphine Chabanne for a PDF at D.Chabanne@murdoch.edu.au

 

Project Funding:
For financial, technical and logistical support, we thank the Swan River Trust, Fremantle Ports and Fremantle Sailing Club. Field research was conducted under the conditions of licenses, authorities and permits from the Western Australia Department of Parks and Wildlife (permit numbers SF008067, SF008682, SF009286 and SF009874) and the Murdoch University Animal Ethics Committee (permit numbers W2342/10 and R2649/14).

 

For further information on the Coastal and Estuarine Dolphin Project and Indo-Pacific bottlenose dolphins in Perth metropolitan waters, see also following papers:

Chabanne, D., Finn, H., Salgado-Kent, C., and Bejder, L. (2012). Identification of a resident community of bottlenose dolphins (Tursiops aduncus) in the Swan Canning Riverpark, Western Australia, using behavioural information. Pacific Conservation Biology 18, 247-262. doi:  10.1071/PC120247

Donaldson, R., Finn, H., Bejder, L., Lusseau, D., and Calver, M. (2012a). Response: social learning of risky behaviour: importance for impact assessments, conservation and management of human–wildlife interactions. Animal Conservation 15, 442-444. doi: 10.1111/j.1469-1795.2012.00601.x

Donaldson, R., Finn, H., Bejder, L., Lusseau, D., and Calver, M. (2012b). The social side of human-wildlife interaction: wildlife can learn harmful behaviours from each other. Animal Conservation 15, 427-435. doi: 10.1111/j.1469-1795.2012.00548.x

Donaldson, R., Finn, H., and Calver, M. (2010). Illegal feeding increases risk of boat-strike and entanglement in bottlenose dolphins in Perth, Western Australia. Pacific Conservation Biology 16, 157-161. doi: 10.1071/PC100157

Finn, H., Donalson, R., and Calver, M. (2008). Feeding Flipper: a case study of a human-dolphin interaction. Pacific Conservation Biology 14, 215-225. doi: 10.1071/PC080215

Stephens, N., Duignan, P.J., Wang, J., Bingham, J., Finn, H., Bejder, L., et al. (2014). Cetacean morbillivirus in coastal Indo-Pacific bottlenose dolphins, Western Australia. Emerging Infectious Disease Journal 20, 666-670. doi:  10.3201/eid2004.131714

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