Elsevier

Estuarine, Coastal and Shelf Science

Volume 181, 5 November 2016, Pages 266-276
Estuarine, Coastal and Shelf Science

An obligate beach bird selects sub-, inter- and supra-tidal habitat elements

https://doi.org/10.1016/j.ecss.2016.08.050Get rights and content

Highlights

  • Few vertebrates are obligate beach animals.

  • Sandy shore habitats were quantified using imagery and LiDAR.

  • Comparison of breeding versus absence sites of a beach plover revealed specific habitat selection.

  • Marine and terrestrial elements featured in breeding territory selection.

  • Sandy shore obligate species are both terrestrial and marine animals.

Abstract

Few habitat models are available for widespread, obligate, high-energy sandy shore vertebrates, such as the Eastern Hooded Plover Thinornis cucullatus cucullatus. We examined habitat attributes which determined the difference between sites where plovers breed and randomly-selected absence sites (determined from long-term systematic monitoring). A variety of habitat variables were derived from aerial photography and bathymetric and terrestrial Light Detection And Ranging (LiDAR) data. Logistic regression against eight candidate variables, in a model selection framework, revealed considerable support for four variables with respect to explaining the presence of breeding territories. In particular, the amount of unvegetated dune and foredune which was unvegetated, and the amount of intertidal and sub-tidal reef were positively associated with the presence of breeding territories. Thus, plovers apparently select certain habitat in which to breed, involving sub-tidal, intertidal and supra-tidal habitat elements. The model also helps explain the virtual absence of breeding plovers from long sections of superficially suitable habitat, such as the fourth longest continuous beach in the world.

Introduction

Ocean shores represent the most distinct ecological interface, between marine and terrestrial ecosystems, on the planet (Schlacher et al., 2008). Sandy shores differ from marine or terrestrial habitats in that there is little primary productivity on beaches, rather ecological subsidies occur from marine and terrestrial environments (Huijbers et al., 2013). Coastal wildlife dependent on beaches directly exploit these energy flows through scavenging on beach-cast carrion or preying upon infauna, which themselves depend on energetic subsidies (Spiller et al., 2010, Huijbers et al., 2013). While sandy shores are extensive, they are highly varied, in terms of geomorphology, sand grain size, and biodiversity (McLachlan and Brown, 2006). For example, benthic infauna is patchily distributed, being influenced by a range of factors including sediment grain size, wave action, and anthropogenic stressors such as beach nourishment (Schlacher et al., 2008).

Few vertebrates can be considered high-energy, sandy-shore obligates; those that are, are not well studied. A classification of niche specialisation of coastal wildlife is currently unavailable, although it is clear there are differences in the way wildlife uses beaches, and we provisionally suggest a classification here (Fig. 1). Sandy coast obligate species may exploit resources in near-shore hinterlands (e.g. dunes), from the beach itself, and from the intertidal zones. Thus, their habitat includes marine and terrestrial elements. They rely on these areas to provide resources for foraging, shelter (from weather and predators) and breeding (McLachlan and Brown, 2006).

One prominent group of sandy shore obligate vertebrates includes populations of particular coastal shorebirds. Many of these species are under conservation stress, and are the subject of ongoing conservation efforts (e.g. Piping Plover Charadrius melodus, Wemmer et al., 2001, Shore Plover Thinornis novaeseelandiae, Marchant and Higgins, 1993, Hooded Plover Thinornis cucullatus, Maguire et al., 2013, Chatham Island Oystercatcher Haematopus chathamensis, Department of Conservation, (2001)). Shorebirds which occupy sandy shorelines are often widespread at low densities when they breed (Page et al., 1983, Marchant and Higgins, 1993, Weston et al., 2009), with breeding territory formation being driven presumably by competition for resources required for producing young (Brown, 1969, Sergio et al., 2009). Because of their widespread distributions, there is a tendency for managers and ecologists to assume that all coastal high energy sandy shorelines (beaches) represent ‘habitat’ of equivalent suitability or quality for these birds, despite the occurrence of substantial stretches of unoccupied beach (see, for example, Fig. 1 in Weston et al., 2012). This assumption has made it difficult to assess population viability, including determining carrying capacity of coastlines, and to identify priority breeding habitats. Conservation management for coastal obligates has focused largely on improving reproductive success (Weston et al., 2003), however the availability of breeding territories is also likely to be critical for recovery of these taxa (Wemmer et al., 2001). Thus, an improved understanding of which beaches represent habitat, and the factors which influence suitable habitat, is required to improve species management. Additionally, such understanding is required to help predict the impact of rising sea levels on species viability (Convertino et al., 2012). Shorebirds are also considered to be valuable indicators of sandy shore ecosystems, and enjoy substantial public interest and engagement, which assists with the attainment of management objectives (Schlacher et al., 2014, Schlacher et al., 2015).

Habitat models have become prominent features of species management, especially for species which are widespread, rare or both (e.g., Guisan and Zimmermann, 2000, Klar et al., 2008, Convertino et al., 2011, Convertino et al., 2012). They offer insights into the extent of viable habitat for species (Convertino et al., 2011, Gratto-Trevor, 1996, Meager et al., 2012, Schlacher et al., 2013), to model different conservation options (e.g., Wemmer et al., 2001, Murray et al., 2011) and have even been used to help identify stakeholders in species conservation (Weston et al., 2012). The vast majority of models are terrestrial (e.g. Lauver et al., 2002), though some marine seafloor models are also available but are often restricted by geographic extent due to the lack of data availability in coastal zones (Ierodiaconou et al., 2011). Mapping the seafloor is difficult along coastal margins, especially exposed coasts, which present a range of challenging obstacles due to wave action and turbidity (Chust et al., 2010). Habitat models of coastal biodiversity are uncommon (Ozesmi and Mitsch, 1997, Willems et al., 2008), though a few exceptions model the habitat suitability of coastal shorebirds (Convertino et al., 2011, Convertino et al., 2012, Meager et al., 2012), and of those, are often restricted to the use of supra-tidal or intertidal data only. One challenge to building habitat models in coastal environments is the feasibility of collecting baseline data on the presence/absence of species, along with descriptions of underlying habitat features both above and below the water over large areas. Fortunately, developments in remote sensing, and especially the application of Light Detection And Ranging (LiDAR) technologies to coasts, hold great promise in mapping habitat of coastal biodiversity (Goodale et al., 2007, Ledee et al., 2008; Zavalas et al., 2014; Jalali et al., 2015). LiDAR can provide high resolution digital elevation models and surface complexity information with seamless mosaics over large geographic extents across the common terrestrial-marine divide that can be used to characterise habitats (Vierling et al., 2008, Kennedy et al., 2014). In addition, the growing use of volunteers, or Citizen Scientists, in the collection of monitoring data provides a means by which presence-absence of species can be confirmed across much larger areas than is possible by individual researchers (Greenwood, 2007, Dunn and Weston, 2008).

In this study, we develop a simple habitat model for an obligate coastal vertebrate, which considers supra-, inter- and sub-tidal variables. We aim to examine whether any habitat preferences exist in the selection of breeding territories by this species, and if so, to document those factors associated with suitable habitat. We do not address habitat quality but recognise that breeding success data could underpin a habitat quality model in future.

Section snippets

Methods

The Eastern Hooded Plover Thinornis cucullatus cucullatus is a threatened, obligate, beach-nesting shorebird which occurs in temperate south-eastern Australia. Populations have long been in decline, and the species has become locally extinct in parts of their former range as a result multiple threats including human disturbance and interference, habitat modification and altered predator environments including introduced carnivorous, and superabundant omnivorous, predators (Dowling and Weston,

Results

Table 1 presents summary statistics for the variables measured. The 512 model set yielded eight models with substantial support (delta AICc < 2; Table 2). Four variables had considerable support (variable weights >0.5) and were positively related to territory selection (Table 3). The amount of dune in breeding territories was the most influential variable identified by model selection with a variable weight of 0.91 (Table 3). The mean predicted probability of occurrence for this variable

Discussion

As is usual for shorebirds, Hooded Plovers are highly mobile - regular movement between breeding and flocking sites is evident and movement rates are significant, especially for non-breeding adults and juveniles (Weston et al., 2009). However, while the taxon is mobile and its distribution highly dispersed, distinct fine scale distributional patterns are evident - it does not occupy all parts of high energy sandy coasts (Weston et al., 2009, Driessen and Maguire, 2015). This indicates that

Acknowledgments

Funding was provided by BirdLife Australia's Beach-nesting Birds project, via the Australian Government's Caring for Our Country Programme. We thank the Department of Environment and Primary Industries (Victoria, Australia) and the Future Coasts Program for access to the LiDAR data. Thanks to Graeme Newell and Anna Cuttriss (Department of Environment and Primary Industries) for helpful discussions and site photographs, and to Thomas Schlacher and two anonymous referees. Thanks to Estelle Barker

References (86)

  • G.S. Maguire et al.

    Being beside the seaside: beach use and preferences among coastal residents of south-eastern Australia

    Ocean Coast. Manag.

    (2011)
  • U. Ozesmi et al.

    A spatial habitat model for the marsh-breeding red-winged blackbird (Agelaius phoeniceus L.) in coastal Lake Erie wetlands

    Ecol. Model.

    (1997)
  • T.A. Schlacher et al.

    Metrics to assess ecological condition, change, and impacts in sandy beach ecosystems

    J. Environ. Manag.

    (2014)
  • T.A. Schlacher et al.

    Golden opportunities: a horizon scan to expand sandy beach ecology

    Estuarine Coast. Shelf Sci.

    (2015)
  • M.A. Schlaepfer et al.

    Ecological and evolutionary traps

    Trends Ecol. Evol.

    (2002)
  • L.C. Wemmer et al.

    A habitat-based population model for the great Lakes population of the Piping Plover (Charadrius melodus)

    Biol. Conserv.

    (2001)
  • W. Willems et al.

    Where is the worm? Predictive modelling of the habitat preferences of the tube-building polychaete

    Lanice Conchilega

    (2008)
  • H.L. Beyer

    Geospatial Modelling Environment (Version 0.7.2.1)

    (2012)
  • A. Bock et al.

    The role of beach and wave characteristics in determining suitable habitat for three resident shorebird species in Tasmania

    J. Coast. Res.

    (2016)
  • L. Brotons et al.

    Presence–absence versus presence-only modelling methods for predicting bird habitat suitability

    Ecography

    (2004)
  • J.L. Brown

    Territorial behaviour and population regulation in birds: a review and re- evaluation

    Wilson Bull.

    (1969)
  • D.M. Bryant et al.

    Intraspecies variation in avian energy expenditure: correlates and constraints

    Ibis

    (1988)
  • K.P. Burnham et al.

    Model Selection and Multimodel Inference

    (2002)
  • R.M. Chefaoui et al.

    Assessing the effects of pseudo-absences on predictive distribution model performance

    Ecol. Model.

    (2008)
  • R. Cousens et al.

    Just how bad are coastal weeds? Assessing the geo-eco-psycho-socio-economic impacts

    (2013)
  • A.W. Crall et al.

    Improving and integrating data on invasive species collected by citizen scientists

    Biol. Invasions

    (2010)
  • A. Cuttriss et al.

    Breeding habitat selection in an obligate beach bird: a test of the food resource hypothesis

    Mar. Freshw. Res.

    (2015)
  • Department of Conservation

    Chatham Island Oystercatcher Recovery Plan 2001–2011. Threatened Species Recovery Plan 38

    (2001)
  • C.F. Dormann et al.

    Methods to account for spatial autocorrelation in the analysis of species distributional data: a review

    Ecography

    (2007)
  • B. Dowling et al.

    Managing a breeding population of the Hooded Plover Thinornis rubricollis in a high-use recreational environment

    Bird. Conserv. Int.

    (1999)
  • DPIPWE

    Impact of Sea Level Rise on Coastal Natural Values in Tasmania. Natural and Cultural Heritage Division

    (2016)
  • J. Driessen et al.

    Report on the 2014 Biennial Hooded Plover Count

    (2015)
  • J.E. Dugan et al.

    Marine macrophyte wrack inputs and dissolved nutrients in beach sands

    Estuaries Coasts

    (2011)
  • A.M. Dunn et al.

    A review of terrestrial bird atlases of the world and their application

    Emu

    (2008)
  • G. Ewers et al.

    Report on the 2010 Biennial Hooded Plover Count

    (2011)
  • H. Galbraith et al.

    Global climate change and sea level rise: potential losses of inter-tidal habitat for shorebirds

    Waterbirds

    (2002)
  • S. Garnett et al.

    Action Plan for Australian Birds 2010

    (2011)
  • R. Goodale et al.

    Mapping Piping Plover (Charadrius melodus melodus) habitat in coastal areas using airborne LiDAR data

    Can. J. Remote Sens.

    (2007)
  • C.L. Gratto-Trevor

    Use of landsat TM imagery in determining important shorebird habitat in the outer Mackenzie Delta, Northwest Territories

    Arctic

    (1996)
  • J.J.D. Greenwood

    Citizens, science and bird conservation

    J. Ornithol.

    (2007)
  • N. Guisan et al.

    Predictive habitat distribution models in ecology

    Ecolical Model.

    (2000)
  • S.M. Haig et al.

    Mate, site, and territory fidelity in piping plovers

    Auk

    (1988)
  • B.S. Halpern et al.

    Evaluating and ranking the vulnerability of global marine ecosystems to anthropogenic threats

    Conserv. Biol.

    (2007)
  • Cited by (9)

    • Natural and anthropogenic processes influence the occurrence of vertebrate fauna in coastal dunes

      2022, Estuarine, Coastal and Shelf Science
      Citation Excerpt :

      These species could be considered ‘Terrestrial generalists’, such that coastal dunes could be considered a coastal extension of terrestrial (hinterland) habitat (Fig. 6). We did not detect patterns in zonation suggesting dune obligate species (sensu Ehmke et al., 2016), but recognise that our sampling did not encompass the extent of dunes into hinterland areas. Zonation patterns in coastal dunes can evidently vary within the same species between locations, and interannually.

    • Non-breeding habitat selection of a sandy shore obligate shorebird

      2022, Estuarine, Coastal and Shelf Science
      Citation Excerpt :

      This study did not find a significant association between beach area or dune ‘sandiness’ with preferred non-breeding habitat. However, Ehmke et al. (2016) demonstrated that sandy dune and foredune is important for habitat selection of breeding hooded plovers, and it might conceivably have an influence on non-breeding hooded plovers. In particular, foredune and dune areas, as well as estuaries (associated with sandy shoreline) likely represent critical refugia for this taxon from the more intense and frequent storms and high tide events that limit beach area in winter (McInnes and Hubert, 2003).

    • Foraging behaviour of an obligate, sandy shore predator

      2020, Estuarine, Coastal and Shelf Science
      Citation Excerpt :

      The eastern subspecies of Hooded Plover is a threatened, medium-sized sandy shore obligate shorebird endemic to south-eastern Australia. In Victoria, they prefer high-energy beaches backed by open, sandy dunes and foredunes (Cuttriss et al., 2015; Ehmke et al., 2016). Birds forage at all levels of the beach; from the swash zone to the dunes (Weston, 2007).

    • The fox and the beach: Coastal landscape topography and urbanisation predict the distribution of carnivores at the edge of the sea: Beach Fox Habitat Choice

      2020, Global Ecology and Conservation
      Citation Excerpt :

      As a consequence, tall contiguous dunes may effectively ‘concentrate’ foxes in a narrow strip of frontal dunes seawards bordering the un-vegetated part of the beach. Because foredunes backed by higher primary dunes are also the preferred habitat for many ground-nesting birds, such as oystercatchers and plovers (Meager et al., 2012; Ehmke et al., 2016; Maslo et al., 2016a, 2016b, 2019), landscape features may modify the impact of invasive species on exposed beaches. Red foxes are part of the urban fauna in many cities globally (Marks and Bloomfield, 2006; Cove et al., 2012; Duduś et al., 2014; Scott et al., 2014; Villaseñor et al., 2014).

    View all citing articles on Scopus
    View full text