A Study on Ecological Relationships between Crab Plover and Oystercatcher with prey Organisms in Sajjafi Mudflats

Subject Areas : environmental management

Morteza Naderi ¹ , Mastoureh Darabi ²

1 - Assistant Professor, Department of Environmental Sciences, Faculty of Agriculture and Natural Resources, Arak University, Arak, 38156-8- 8349, Iran. (Corresponding Author)
2 - M.Sc., Department of Environment, Department of Natural Environment and Biodiversity, Natural History Museum and Genetic Resources, Tehran, Iran

Received: 2010-03-09 Accepted : 2009-04-10 Published : 2015-09-23

Keywords: Prey-predator relationships, Distance methods, Spatial distribution patterns, Cockles, Waders,

Abstract :

Introduction: Ecological relations between foragers and their prey in two species of waders, crabplover (Dromas ardeola) and oystercatcher (Haematopus ostralegus), were studied in Zohre rivermudflats over 9 months between summer 2004 to winter 2005.Material & Methods: Seven line transects each with about 400 meters were detected in two sides ofthe river that four of which were located in the river estuary. The main food of crab plover andoystercatcher were determined via direct sighting, collection of shells scattered around nests, huntingand exploring the stomach contents Variable Circular Plot or VCP and distance to nearestneighborhood and quadrate methods were used for birds, crabs and cockles density and abundanceestimation respectively. Then acquired data were analyzed by DISTANCE software.Results: This study showed that the main food of crab plover and oystercatcher are Eurycarcinusorientalis and cockles from Cardidae family (Trachycardium and Laevicardium genuses)respectively. Crab populations are generally distributed in patches and the area between patches istaken to be devoid of prey. Foragers (Crab plover) must maximize their rate of energy intake and donot spend time and energy traveling between patches whereas tide is a time limiting factor. In thisstudy it was found that crab plover should select the patch where they obtain the highest intake ratesand its population is highly correlated with crab’s populations ( 2 R = 0.875, P < 0.005). But there is nosignificant relationship between oystercatcher population density distributions with cockles ( 2 R =0.072, P < 0.005). The results suggest that measurement of prey availability can account for preyactivity patterns.

References:

1. McLusky, D.S. & McCrory, M. (1989). A long-term study of an estuarine mudflat subject to industrial pollution. Scientia Marina 53 (2-3) In: (ed. J.D. Ros) Topics in marine biology. Proceedings of the 22^nd European Marine Biological Symposium.


2. Green, J. (1968). The biology of estuarine animals. Sedgewick and Jackson, London

1. McLachlan, A. (1990). Dissipative beaches and macrofauna communities on exposed intertidal sands. Journal of Coastal Research 6: 57-71.


2. Moreira, F. (1994). Diet, prey size selection and intake rates of Black-Tailed Godwits Limosa limosa feeding on mudflats. IBIS.136 (3) pp349-355.


3. Burger, J., Niles, L. & Clarke, K.E. (1997). Importance of beach, mudflat and marsh habitats to migrant shorebirds on Delaware Bay. Biological conservation. 79 (2-3) pp 283-292.


4. Ina stradins (2002). Birds and Their Interaction with Prey Population, Waders, Jonathan Metcalf publication, London, pp. 448.


5. JohnVangelis. 2002. Habitat Selection and Hatching Success of Eurasian Oystercatchers in Relation to Nesting Yellow-legged Gulls and Human Presence. British Wildlife. 12(3): 119-128.


6. Fawler & Longsluve 1984. Assessing the Effectiveness of Predator Exclosures for Plovers. Wilson Bull. 112(1): 14-20.

8. Rands M. R. W. (1996). Ornithology and Family Dromadidae (Crab plover). University of Minnesota Press, Minneapolis and London. pp. 307–309.


9. Goss-Gustard, J. D. (1977). The Ecology of the Wash. III. Density Related Behaviour and the Possible Effects of a Loss of Feeding Grounds on Wading Birds (Charadrii). Journal of Applied Ecology 14, 721–739.


10. Meadows, S., & Campbell, J.I. (1989). An Introduction to Marine Science. John Wiley and Sons publication Company, New York, 285 pp.

12. Bibby, C.J. & Burgess, N. D. & Mustoe, S. (1992). Bird Census Techniques, Harcourt Science and Technology Company press, New York, 301pp.


13. Charles J. Krebs,(1999).Ecological Methodology,2nd edition. Jim Green publication, USA. pp 618  13


14. Charles J. Krebs. (1978).Ecology, The Experimental Analysis of Distribution and Abundance. Benjamin Cummings publication.