Species Diversity and Feeding Guilds of Birds in Paya Indah Wetland Reserve, Peninsular Malaysia

MATERIALS AND METHODS

Study Site
Paya Indah (beautiful swamp) Wetland Reserve is encompassing of 3050 ha which consists of peat swamps and large ex-tin mining lakes. The study area lies adjacent to Malaysia's administrative capital of Putrajaya within the quadrant of 101° 10' to 101° 50' longitude and 2° 50' and 3° 00' latitude. Paya Indah has diverse topography, vegetative features and climate with splendid natural setting which directly affect the occurrence and distribution of bird species.

The research area was divided into five major habitats based on existing conditions and vegetation structure namely; (1) Marsh swamp, (2) Lotus swamp, (3) Open water body, (4) Terrestrial area and (5) Patchy shrubland.

Marsh Swamp
About 85% of marsh swamp areas are covered with water and 15% with terrestrial area. Marsh swamps densely covered with aquatic plants namely Eleocharis dulcis, Lepironia articulata, Stenochlaena palustris, Philydrum lanuginosum, Scirpus sp., Carex sp., Sagittaria latifolia, Elodea sp., Phragmites karka, Nymphaea rubra, Nymphaea Pubescens, Nelumbo nucifera, Scleria purpurascens, Panicum repends, Gleichenia linearis, Lycopodium cenum and scattered tress such as Acacia auriculiformis, A. mangium, Macaranga lanrius, Peltophorum pterocarpum, Cinnamonum iners, Melicope glabra and Melastoma malabathrium. These areas are shallow in water depth and rich in food resources such as fishes, amphibians, insects, snails and invertebrates larvae.

Lotus Swamp
About 90% of lotus swamp areas are covered by water and 10% by terrestrial land. Lotus swamps are extensively covered with Nelumbo nucifera, N. nouchali, N. pubescens, Eleocharis dulcis, Elodea canadensis, Lepironia articulata, Phragmites karka reeds and Typha angustifolia. The land is covered with Acacia auriculiformis and A. mangium.

Open Water Body
About 90% of the area is covered by water and 10% by terrestrial land. Open water bodies mostly covered with emergent vegetation such as Nymphaea odorata, Potamegoton sp., Eleocharis dulcis, Myriophyllum spicatum, Salvinia molesta, Utricularia aurea, Scirpus holschoenus, S. sylvaticus, S. californicus, S. mucronatus, S. maritimus and along the edges Eleocharis dulcis, Lepironia articulata, Phylidrum languginosum, Scleria purpurascens, Scirpus sp., Carex sp., Sagittaria latifolia and Elodea sp. Open water bodies are rich in invertebrates, amphibians and fishes.

Terrestrial Area
About 85% of the area is covered with scattered trees and grasses and 15% by small ditches or somewhere stagnant water ponds. The most dominant tree species are Mimusops elengi, Fragraea fragrans, Cassia fistula, Tectona sp., Albizia julibrissin, Syzygium sp., Delonix regia, Samanea saman, Acacia auriculiformis, A. mangium, Melicope glabra, Melastoma malabathricum, Ficus sp. and the ground is extensively covered with Bald grass Imperata cylindrica, Cynodon dactylon, Wedelia trilobata, Nephrolepis acutifolia, Artocarpus altilis Asystasia gangetica, Peltophorum pterocarpum, Plumeria obtuse, Asystasia gangetica and Passiflora caerulea.

Patchy Shrubland
About 85% of the area is covered with dense vegetation and 15% covered by scattered trees and aquatic vegetation. Patchy Shrublands are mainly cluster and patches of shrubs and small trees between pools, mound hills and along the pathways. The dominant plant species are Acacia auriculiformis, A. mangium, Fragraea fragrans, Delonix regia, Alstonia scholaris, Samanea saman, Macaranga lanrius, Ficus rubiginosa, F. benjamina, F. fistulosa, Lagerstroemia speciosa, Melastoma malabathricum, Wedelia trilobta, Nephrolepis acutifolia and Asystasia gangetica.

Observations
Bird surveys were carried out at Paya Indah Wetland Reserve by using distance sampling-point count method to determine species diversity and feeding guilds of different bird species within November 2007 to January 2009. Sixty one point count stations 300 m apart from each other were established within the study area. The main objective of using 300 m interval distance apart between points was to avoid detecting the same birds at more than one station. Each point count station was surveyed fifteen consecutive times at monthly interval to achieve reliable diversity estimate because the replication of point count stations increased precision and provides reliable results (Petit et al., 1995; Smith et al., 1993). The survey was done early in the morning from 7:30 to 11:00 am. The methodology was followed as described by Buckland et al. (2004), Blonde et al. (1981) and Bibby et al. (2002).

The detection of birds within each point count station was done for 10 min. Ten minute enables to detect many species of birds with minimal efforts and disturbance. Ten minutes point counts provide more reliable results as compared to shorter time because more species are usually detected and efficiency declined substantially after 10 min (Jimenez, 2000; Gutzwiller, 1991; Smith et al., 1993; Dawson et al., 1995; Lynch, 1995; Petit et al., 1995; Lee and Marsden, 2008). During each point count survey we recorded species and number of individuals detected by sight or sound.

The relative abundance (%) of waterbird species was determined by using expression:

where, n is numbers of particular recorded bird and N is total recorded bird species.

The study area was divided into five major habitats based on existing conditions and vegetation structure namely., (1) Lotus swamp, (2) Marsh swamp, (3) Open water body, (4) Terrestrial area and (5) Patchy shrubland. Species diversity, species richness and evenness were determined in study area and within five habitats by using standard Species Diversity Indices method (Henderson and Seaby, 2007; Ludwig and Reynolds, 1988) to examine the variability of bird species among five habitats. The trophic structure was also determined in study area and within five habitats based on observed foraging behavior of bird species during the surveys.

RESULTS AND DISCUSSION

A total of 13872 individuals of 100 species of birds that represented 38 families were detected within November 2007 to January 2009. The results shows that the five most dominant bird species were Treron vernans (12.420%), Pycnonotus goiavier (12.132%), Geopelia striata (7.583%), Porphyrio porphyrio (6.877%) and Streptopelia chinensis (6.336%). The most rare bird species were Haliastur indus, Circus aeruginosus, Haliaeetus leucogaster, Treron curvirostra, Clamator coromandus, Eudynamys scolopacea, Dicrurus leucophaeus, Emberiza aureola, Prinia rufescens, Nectarinia sperata, Picumnus innominatus, Phylloscopus inornatus and Gallirallus striatus (each 0.007%) (Appendix 1).

The six most dominant families based on number of species detected were Ardeidae (9 species), Sylviidae (7 species), Nectariniidae (7 species), Rallidae (7 species), Columbidae (6 species) and Cuculidae (6 species). The least dominant families were Charadriidae, Coraciidae, Dicruridae, Emberizidae, Hirundinidae, Jacanidae, Motacillidae, Muscicapidae, Oriolidae, Pachycephalidae, Ploceidae, Passeridae, Podicipedidae, Rhipiduridae, Turdidae and Turnicidae with only one species each. However, the three most dominant families with highest number of observations were Columbidae (3721 observations; 26.823%), Pycnonotidae (1696 observations; 12.226%), Rallidae (1485 observations; 10.70%) and the rarest families were Dicurridae and Emberizidae (one observation each; 0.007% each) (Table 1; Appendix 2).

The bird species diversity, richness and evenness in different habitats were determined using species Diversity indices method (Henderson and Seaby, 2007; Ludwig and Reynolds, 1988). The highest bird diversity was observed in Marsh swamp and lowest in Patchy shrubland (Shannon diversity index N₁ = 27.16 and N₁ = 22.51, respectively; Table 2). The highest bird species richness was also observed in Marsh swamp (Margalef’s Richness Index R₁ = 9.52) while the lowest was observed in Open water bodies (Margalef’s Richness Index R₁ = 7.35). The distribution of individuals among the species was higher in Marsh Swamps and lower in Patchy Shrubland (Pielou J Evenness = 0.71 and 0.67, respectively) (Table 2; Appendix 3).

Bird species diversity comparison among five habitats was also determined by using ANOVA and Tukey’s (HSD) comparison test. The result showed that bird species diversity among the five habitats was significantly different (F₄, 495 = 8.82 p<0.0001) (Table 3).

The bird species were divided into eight feeding guilds based on observed foraging behaviours and habitat use during the 15 consecutive month’s surveys. The results clearly showed that the Insectivore was the most dominant group of birds (37.0%) as compared to Omnivore (19.0%), Carnivore/Insectivore/Pisicivore (17.0%), Frugivore/Insectivore (8.0%), Nectarivore/Insectivore (7.0%), Granivore/Insectivore (6.0%), Carnivore/Insectivore and Granivore (3.0% each) in Paya Indah Wetland Reserve (Table 4).

Composition of feeding guild based on habitats was also determined to examine the importance of the habitats for different groups. The results showed that Insectivore was the most dominant group of birds as compared to other feeding guilds in all habitat types. The least dominant guild in all habitat types was the Carnivore/Insectivore (Table 5).

Monitoring bird species diversity is very important to describe the community structure and make comparisons among the different habitats (Goldsmith, 1975; Everett, 1978; Rafe et al., 1985; Robertson and Liley, 1998). Paya Indah Wetland Reserve has diverse vegetation and habitats. The vegetation diversity and richness directly affect species diversity and richness of birds, because it provides heterogeneous and suitable sites for foraging, nesting and roosting (Karr and Roth, 1971; Cody, 1981; Canterbury et al., 1999; Soderstrom and Part, 1999).

Table 1:	Ranking of bird families according to No. of species detected in Paya Indah Wetland Reserve, Peninsular Malaysia

Table 2:	Diversity of bird species according to habitat type in Paya Indah Wetland Reserve

Table 3:	Comparison of bird species among habitats (Tukey’s HSD)
Values having the same lette(s)r are not significant

This study also showed that bird species diversity and feeding guilds are significantly different among habitats.

Table 4:	Classification of feeding guilds based on foraging behaviors in Paya Indah Wetland Reserve

Table 5:	Feeding guilds of bird species according to habitat types

We recorded 13872 birds belonging to 100 species and 38 families. We also recorded 84 species in marsh swamp, 57 species in lotus swamp, 68 species in patchy shrubland, 75 species in terrestrial area and 55 species in open water body.

The results showed that Marsh swamp is highly attractive for different bird species as compared to other habitats since it provides heterogeneous habitats that attracted high diversity of birds through offering shelter, abundant food, suitable nesting and safe roosting sites for different groups of birds (Macdonald, 1977). The main reason for the difference in habitat preference by bird species could be due to different vegetation types (Weller, 1978) and abundant food resources (Puttick, 1984) such as insects, fishes, frogs, lizards, mouse and vegetable matter. However, other factors such as weather (rainfall), social interactions and predators (Caldwell, 1986; Butler and Vennesland, 2000; Rivers, 2000) such as Aviceda leuphotes, Accipiter sp., Circus aeruginosus, Varanus salvator, Varanus goulgii, Python reticulatus, Ophiophagus hannah and Naja naja may also affect the distribution, foraging, nesting and roosting behaviour of bird species (Kerbs, 1978; Baldassarre and Bolen, 1994; Haukos et al., 1998).

We determine the relative importance of different habitats for foraging of wetland dependent and non-wetland dependent bird species. We observed that wetland dependent birds such as ducks, grebes and geese used open water bodies with shallow water depth particularly to forage on seeds and vegetable matter namely Myriophyllum spicatum, Creatophyllum demersum, Elodea sp. and Potamogeton sp. Swamphens, moorhens and crakes used marsh swamps and lotus swamps to feed on soft shoots, stems, herbs, seed of reeds and rushes such as Eleocharis dulcis, Nelumbo nucifera and Myriophyllum spicatum. They also feed on small vertebrates such as tadpoles, fishes and invertebrates such as larvae of insects. Bitterns and herons hide in thick vegetation of Eleocharis dulcis, Scleria purpurascens, Lepironia articulate and Phragmites karaka in shallow water to catch variety of aquatic insects, nektons, pleustones, tadpoles and fishes. Egrets were often running with raised wing to chase their prey in shallow water mostly on amphibians, fish and insects. Jacanas picked snails, insects and invertebrates by walking slowly on the leaves of water lilies. Waterhens and water cocks frequently used wet moist soil in shallow water and along the edges of water bodies to probe in mud on variety of food items such as worms, insects and adjacent terrestrial areas especially covered with Scleria purpurascens and Panicum repends grasses to forage on seeds and vegetable matter. Kingfishers used variety of habitats to hunt on fishes and insects and often perched on trees along the edge of lakes and adjacent lakes areas. Other species such as plovers, snipes and sandpipers used wet grounds (soft soil of muddy shorelines) for probing or picking up food items such as worms and insects. The edges preference feeding may be explained in term of higher level of prey availability and easy to catch prey as was also reported by McIver and Odum (1988). Such types of foraging behavior in birds have also been reported by Hancock (1999), Oglvie and Rose (2002), Pringle (1985), Clary (2007), Pranty et al. (2000), Ali and Daniel (1983), John et al. (1986) and Fry and Fry (1992).

The study shows further that the guild Insectivore which comprised of terrestrial, arboreal foliage gleaning, bark gleaning and sallying insectivores was the most dominant group of birds as compared to other feeding guilds namely Omnivore, Carnivore/Insectivore/Pisicivore, Frugivore/Insectivore, Nectarivore/Insectivore, Granivore/Insectivore, Granivore and Carnivore/Insectivore. However, the feeding guilds also differ from habitat to habitat. The diverse vegetation has had strong and pervasive effect on avian species distribution. This could be due to the richness and heterogeneity of the emergent vegetation (e.g., Eleocharis dulcis, Nelumbo nucifera, Salvinia molesta, Scleria purpurascens), submerged vegetation (e.g., Myriophyllum spicatum, Potamogeton illionensis, Eleocharis radicans, Creatophyllum demersum, Elodea sp.), herbaceous plants (e.g., Cyperus sp. Junicus effeuses, Panicum repens, Scirpus atrovirens, Phragmites karka), shrubs (e.g., Melastoma malabathricum) and fruiting trees (e.g., Fagaea fragrances, Syzygium sp., Ficus fistulosa, F. maclellandi, F. benjamina, Cinnamomum iners, Melicope glabra). The diversity of flora subsequently affected the abundance and diversity of birds, insects, amphibians, fishes, reptiles and small mammals. Fruiting trees frequently provide fruits that attracted Frugivore/Insectivore and Omnivore birds such as pigeons, bulbuls, orioles, mynas and starlings. Flowering trees such as Lagestroemia speciosa, Dillenia grandifolia, Dillenia suffruticosa and Cassia fistula have also been observed to attract Nectarivore/Insectivore birds such as sunbirds and spiderhunters. The abundance of insects, amphibians, reptiles and small mammals has also attracted waders and raptors.

CONCLUSION

Based on these results it is concluded that Paya Indah Wetland Reserve provides various types of habitats especially in terms of vegetation and food resources. This area provides optimal combination of resources that allows bird species to fullfill their biological needs such as food, water (for swimming as well as for drinking), cover (for protection from predators and weather) and rest (including protection from natural and human disturbance). All primary feeding guilds Carnivore-/Insectivore/Piscivore, Frugivore/Insectivore, Grainivore/Insectivore, Insectivore, Nectarivore/Insectivore and Omnivore are present in the area. Therefore, the wetland area should be declared as bird sanctuary to protect particularly the wetland dependent birds.

ACKNOWLEDGMENTS

The authors would like to thank Department of Wildlife and National Parks, Peninsular Malaysia to allow conducting this research study at Paya Indah Wetland Reserve. This research was funded by Fundamental Grant Research Scheme 01-10-07-291FR.

APPENDIX

Appendix 1:	Number of observations of bird species in Paya Indah Wetland Reserve, Peninsular Malaysia

Appendix 2:	Classification of bird species according to family in Paya Indah Wetland Reserve

Appendix 3:	Number of observations of bird species according to habitat in Paya Indah wetland reserve