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THE ECOLOGICAL IMPACT OF TREES CANOPY ON THE LIFE OF ARDEA CINEREA

IN BULAKSUMUR ARBORETUM YOGYAKARTA, INDONESIA

Soewarno Hasanbahri and Sena Adibrata Department of Forest Resources Conservation, Faculty of Forestry,

Gadjah Mada University, Yogyakarta, Indonesia Telp No. +62274548816 Facs. No. +62274550541

Email: shasanbahri@ugm.ac.id

ABSTRACT The Bulaksumur Arboretum established about 1963 in Gadjah Mada University Campus, Yogyakarta, Indonesia as a part of the urban forest ecosystem in Yogyakarta City. Up to now, this area use as field practice for the student of Faculty of Forestry. Several trees species grow as introduction plant from The Bogor Botanical Garden and some another trees grow naturally as a result of the student practice. As long as the development of tree species composition, some old trees dead; such as Ochroma lagopus, Dalbergia latifolia, Pterocarpus javanicus, and Delonix regia. The autogenic succession were going on for a long time and it changes significantly the tree canopy of emergent species. In 2005, the bird species of Ardea cinerea as wild-life came and life in this Arboretum, then proliferating by utilizing the trees canopy for nesting and resting. This species have actually an habitat in water areas such as mangrove forest habitat. The social positive impact by the existing of this wild life in the Bulaksumur Arboretum creates unpredictably the conservation atmosphere for the campus society; although they suffer from bad odor of the bird feces. The trees canopy of vertical structure of the Arboretum ecosystem have created a comfortable habitat for many bird species which life in Gadjah Mada University Campus (in 2005 identified about 32 wild bird species). Because of the fast regeneration activity of the Ardea cinerea that make the high population members, so it needs an alternative for cutting down to population size. The ecological impact of the trees canopy in this arboretum related to the architecture branch arrangement of the emergent trees, it creates the suitable position for nesting the bird of Ardea cinerea; and another trees species just for resting. There is a recommendation was suggested for decreasing the number of population of this bird species by pruning the number of plagiotropis branches of the emergent tree canopy, such as Hopea sp. and Pterigota alata trees. The question is: ”Is it possible to be carried out in Bulaksumur Arboretum?” Based on the conservation issues of the Ardea cinerea as protected bird species generally in Indonesia, it should be established the permanent plots for monitoring and investigating the effect of branch pruning on the population size changes of Ardea cinerea. Unfortunately, the arboretum is managed by natural based. So, if the research will be conducted, it should be involved some stakeholders who concern with this bird species and sustainability of the arboretum. Key word: Ecological impact, Ardea cinerea bird, pruning of canopy branch *) The paper presented on the 5th International Canopy Conference titled Forest

Canopy: conservation, climate change and sustainable use. In Bangalore, India, October, 25-31, 2009.

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INTRODUCTION

The ecological study of trees canopy in Indonesia is one of the interesting research field, especially relating to the life of other organism such as birds. This paper reported the investigation of the trees canopy structure and the ecological impact on the life of Ardea cinerea as migration bird in Bulaksumur Arboretum. Formerly, the birds of Ardea cinerea live in the Zoo and Park of “Gembira Loka” in Yogyakarta City.

The Bulaksumur Arboretum was established (about 1963) in Gadjah Mada University Campus, Yogyakarta, Indonesia. This arboretum is recently named with The Ir. Pardiyan Education Forest. Some student activities, such as the Practice of Silvics, the Field practice of Silviculture, the research on the accumulation and decomposition of litter, and the research on wild-bird population and behavior, the biomass growth of trees, the dendrological field practice, and research on the microclimate aspects under the canopy and the noise filtering impact of the arboretum. The location of the Bulaksumur Arboretum is nearby the building of Faculty of Forestry and the building of Gadjah Mada University Administration Central Office (see Photo 1).

Photo 1. The Bulaksumur Arboretum in Campus of Gadjah Mada University (Adopted from Google Earth, 2009)

The Bulaksumur Arboretum is recently as a part of the urban forest ecosystem

in Yogyakarta City. Several trees species grow as introduction plant from The Bogor Botanical Garden and some another trees grow naturally as a result of the student practice. In about 1990, the species composition of vegetation in this arboretum consisted of 31 families with about 64 species (Table 1). Because of the development and the dynamics of the ecosystem, some old trees dead; such as Ochroma lagopus,

Bulaksumur Arboretrum

Biology Arboretum

Central Office of GMU

Fac.of Forestry

Fac.of Biological

Science

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Dalbergia latifolia, Pterocarpus javanicus, Cecrophia peltata, Tectona grandis., and Macaranga tanarius. Then, the autogenic succession were going on for a long time and it changes significantly the tree canopy of emergent species such as Pterigota alata and Eucalypthus deglupta, Swietenia macrophylla, Paraserianther falcataria and Hopea mengerawan.

In the Gadjah Mada University Campus has been supported by the comfortable environment with many trees species. This condition created a welcome habitat for the wild life, especially for birds species. The biodiversity of wild life of birds exploration at Campus of Gadjah Mada University, Yogyakarta in 2005 by the Conservation Forest Resources Department Students Group (Pambudi, 2009 pers.comm.) identified about 32 species of bird (Table 2). Then, since migration bird of Ardea cinerea (Photo 2) came in this campus (it was identified first in about 2005), the population of this birds species increase and they life in the Bulaksumur Arboretum (nearby Faculty of Forestry) and also in the Biology Arboretum (nearby Faculty of Biological Science), for nesting and dwelling in it.

Photo 2. The bird of Ardea cinerea in Bulaksumur Arboretum, Yogyakarta

Tabel 1. The list of tree species in Bulaksumur Arboretum in 1990

No. Family Species 1. Anacardiaceae 1). Anacardium occidentale L.

2). Mangifera indica L. 2. Annonaceae 3).Cananga odorata (Lmk.) 3. Aracaceae 4). Arenga pinnata (Warb) Merr. 4. Araucariaceae 5). Agathis dammara (Lamb.) L.C.Rich 5. Bignoniaceae 6). Spathodea campanulata Beauv. 6. Bombacaceae 7). Ceiba pentandra L. Gaertn.

8). Durio Zibethinus Murr. 9). Ochroma lagopus Swartz.

7. Caesalpiniaceae 10). Cassia siamea Lmk. 11). Cassia fistula L. 12). Cassia javanica L. 13). Delonix regia (Bojer ex Hook.) Raff. 14). Hymenaea ferrucosa Gaertn.

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Table 1. …… continued No. Family Species

15). Peltophorum pterocarpum Back. 8. Casuarinaceae 16). Casuarina Junghuhniana Miq. 9. Combretaceae 17). Terminalia catappa L. 10. Dipterocarpaceae 18). Dipterocarpus cornutus

19). Dryobalanops oblongifolia Dyer. 20). Hopea mengerawan

11. Ebenaceae 21). Diospyros celebica Bakh. 12. Euphorbiaceae 22). Antidesma chasembila Gaertn.

23). Antidesma bunius Spreng 24). Macaranga tanarius (L.) M.A.

13. Gnetaceae 25). Gnetum gnemon L. 14. Guttiferae 26). Calophyllum inophyllum L. 15. Lauraceae 27). Cinnamomum javanicum Bl. 16. Meliaceae 28). Khaya anthotheca C. DC.

29). Swietenia macrophylla King 17. Mimosaceae 30). Acacia auriculiformis A.Cunn ex Bth.

31). Adenanthera pavonea L. 32). Calliandra callothyrsus Meisn. 33). Dalbergia latifolia Roxb. 34). Enterolobium saman 35). Parkia roxburghii G.Don. 36). Paraserianthes falcataria (L.) Nielsen 37). Pithecelobium dulce (Roxb.) Bth.

18. Moraceae 38). Artocarpus heterophyllus Lmk. 39). Cecrophia peltata L. 40). Ficus religiosa L. 41). Morus australis Poir.

19. Myrtaceae 42). Eucalypthus alba Reinw. 43). Eucalypthus deglupta Bl. 44). Eucalypthus urophylla S.T Blake 45). Melaleuca leucodendron (L.) L.

20. Myristicaceae 46). Myristica Fatna Houtt. 21. Papilionaceae 47). Glyricidea sapium (Jack) Kunth ex Walp

48). Pterocarpus indicus Willd. 22. Pinaceae 49). Pinus merkusii Jungh et de Vries 23. Podocarpaceae 50). Podocarpus neriifolius D. Don 24. Rubiaceae 51). Morinda citrifolia L. 25. Rutaceae 52). Murraya paniculata Jack. 26. Santalaceae 53). Santalum album L. 27. Sapindaceae 54). Schleichera oleosa (Lour.) Oken. 28. Sapotaceae 55). Manilkara kauki Dub.

56). Mimosops elengi L. 57). Palaquium obovatum

29. Saxifragaceae 58). Dichroa febrifuga Lour. 30. Sterculiaceae 59). Pterigota alata R. Br.

60). Pterospermum javanicum Jungh. 61). Sterculia foetida L. 62). Theobroma cacao L.

31. Verbenaceae 63). Gmelina arborea Roxb. 64). Tectona grandis L.f.

Resources: Laboratory of Dendrology, Faculty of Forestry, GMU

Because of the bad odour of the feces of Ardea cinerea and also Nycticorax nycticorax birds, the student canteen in Faculty of Biological Science has been closed.

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Then, the complain appears from the people who work in the building and live in the village nearby the Bulaksumur Arboretum. They feel disturbed by unpleasant odour of the bird feces in this arboretum, but they could not do anything for handling the birds. The question is why the Ardea cinerea prefer to life and proliferating in Bulaksumur Arboretum of the Gadjah Mada University Campus? Then, after enlarging their population create a new problem that is the bad odour of their feces. The ecological function of the Bulaksumur Arboretum as an urban forest in Yogyakarta city depend on the sustainability of the canopy structure and the spatial distribution of the tree species. Kershaw (1973) stated that in tropical forest the stratification of the vegetation has been long recognized as one of its characteristic features. The detailed description of the stratification of vegetation forms an important part in the understanding and recording of its structure. This condition can be described by applying the narrow rectangular sample plot, of required length and width (usually not less than 60 m in length, and 8 m has been found to be a convenient width). The Ardea cinerea (grey herons) birds basically live in the wetland areas for feeding and clutching. They have long necks and powerful bills for a long and strong reach. They usually wait on the mud or at the water's edge to snatch passing aquatic prey. They may wade slowly through shallow water or on mud freshly exposed by the tide. They may also stalk fish. They may even dive into deeper water. Grey Herons generally nest in colonies. Preferred nest sites are tall emergent trees, even dead ones. Their nest are large (40-45 cm wide) platforms solidly built out of sticks and lined with grass or fresh leafy branches. The males find and bring nesting materials to the females: the giving and receiving of sticks is done with lots of ritual. It is the female who does most of the actual construction (Elfidasari and Junardi, 2006; Annonimous, 2009). As a consequence of various changes in human land use, many animal populations are displaced into new environments which are often ecologically different from those of their source. By increasing the Ardea cinerea population mainly in Bulaksumur Arboretum, Gadjah Mada University, Yogyakarta, it creates the question: “What kinds of the ecological impact of the trees canopy that make the Ardea cinerea prefer to life in this arboretum?. The objectives of the investigation were to study the canopy structure of the Bulaksumur Arboretum, Gadjah Mada University, and to know how far the trees selection for roosting and nesting or clutching by Ardea cinerea as the bird species that live in this arboretum. Then, based on this information what policy can be suggested for managing the arboretum canopy for controlling the Ardea cinerea and other bird population

THE METHOD OF INVESTIGATION

The Arboretum Bulaksumur, Gadjah Mada University, Yogyakarta, is about 1,0 hectare with rectangular shape (about 80 m x 120 m). By 100%l trees inventory of diameter ≥ 10 cms dbh in 23 plot size 20 m x 20 m, all trees were written the scientific name, measured the tree height (total and free branch), measured the stem diameter (dbh), and identified which tree used as nesting site of the bird of Ardea cinerea. Then, by using rectangular sample plot (20 m x 100 m), then drawing the canopy structure with profile diagram method. The data analysis of the canopy structure is needed to determine the information about the relative density, relative frequency and relative dominance of each tree species. Then, on the basis of the information was combined with information regarding

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the bird’s nest in every tree will be obtained the information of ecological impact of Bulaksumur Arboretum on the Ardea cinerea life. Relating to the complain of unpleasant odor of the bird’s feces, what kind of solution could be suggested for controlling the population of bird and what organization body should be established for managing the action?. After all questions answering, then the further research of bird’s population control could be implemented. Table 2. The list of birds species identified in 2005

No Local name Scientific name 1 Cangak abu Ardea cinerea 2 Bentet kelabu Lanius schach 3 Bondol haji Lonchura maja 4 Bondol jawa Lonchura leucogastroides 5 Bondol peking Lonchura punctulata 6 Burung gereja eurasia Passer montanus 7 Burung madu sriganti Nectarinia jugularis 8 Cabai jawa Dicaeum trochileum 9 Cekakak jawa Halcyon cyanoventris

10 Cekakak sungai Todirhampus chloris 11 Cinenen kelabu Orthotomus ruficeps 12 Cinenen pisang Orthotomus sutorius 13 Cipoh kacat Aegithinia tiphia 14 Cucak kutilang Pycnonotus aurigaster 15 Gemak loreng Turnix suscitator 16 Kekep babi Arthamus lecorhynchus 17 Kepodang Kuduk Hitam Oriolus chinensis 18 Kerak kerbau Acridotheres javanicus 19 Kipasan belang Rhipidura javanica 20 Kowak malam kelabu Nycticorax nycticorax 21 Kuntul kerbau Bubulcus ibis 22 Layang - layang api Hirundo rustica 23 Merbah cerukcuk Pycnonotus goiavier 24 Perenjak Jawa Prinia familiaris 25 Perkutut jawa Geopelia striata 26 Punai gading Treron vernans 27 Raja udang meninting Alcedo meninting 28 Serak jawa Tyto alba 29 Tekukur biasa Streptopelia chinensis 30 Trinil pantai Tringa hypoleucos 31 Walet sapi Collocalia esculenta 32 Wiwik kelabu Cacomantis merulinus

Resource: Pambudi (2009, pers.comm.)

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THE RESULT AND DISCUSSION

1. The Structure of the Bulaksumur Arboretum

Vegetation structure is an organization in the space that filled with the vegetation and form a stand, vegetation types and vegetation associations (Danserau cited by Mueller-Dombois and Ellenberg, 1974). Therefore, trees stand that form in the Bulaksumur Arboretum be understood as an arrangement of plants that form the specific canopy layers. Certain trees soaring into the dominant tree, while the other trees in the layer below it. Each tree has a branching architecture different, so there are tree that canopy as cylindrical-shaped, also a dome-shaped, umbrella-shaped and a cone-shaped. Such canopy condition has allowed other organisms (e.g birds) to select a suitable canopy for nesting and resting. In about 1990, the Bulaksumur Arboretum was composed by 31 families and consists of 64 tree species (as was shown in Table 1 data from Laboratory of Dendrology, Faculty of Forestry GMU). Then, in 2009 some old trees did not find anymore and were changed their position by second canopy layer tree. Based on the recent investigation, the tree species composition consist of 14 families with 20 species only (Table 3). Table 3. Tree species composition of Bulaksumur Arboretum in 2009

No. Family Species 1. Apocynaceae 1). Alstonia scholaris 2 Bombacaceae 2). Ceiba pentandra 3 Caesalpiniaceae 3). Delonix regia 4. Casuarinaceae 4). Casuarina Junghuhniana 5. Combretaceae 5). Terminalia catappa 6. Dipterocarpaceae 6). Dipterocarpus cornutus

7). Hopea mengerawan 7. Ebenaceae 8). Diospyros celebica 8. Malvaceae 9). Hibiscus tiliaceus 9. Meliaceae 10). Khaya anthotheca

11). Swietenia macrophylla 12). Azadirachta indica

10. Mimosaceae 13). Adenanthera pavonea 14). Dalbergia latifolia 15). Paraserianthes falcataria

11. Moraceae 16). Ficus benyamina 12. Myrtaceae 17). Eucalypthus deglupta

18). Melaleuca leucadendron 13. Sapindaceae 19). Pometia pinnata 14. Sterculiaceae 20). Pterigota alata R. Br.

In Bulaksumur Arboretum (1.0 hectare) identified 222 individual trees (diameter ≥ 10 cm dbh) and the large number occupied by Pterigota alata (59 trees), Adenanthera pavonea (38 trees), Paraserianthes falcataria (25 trees), Swietenia macrophylla (17 trees) and Diospyros celebica (17 trees). Each species of tree expressed the relative frequency, relative density, relative dominance and the important value index as in Table 4. This result showed that there were 7 trees species of Pterigota alata (IVI 135.3), Adenanthera pavonea (IVI:33.1), Paraserianther falcataria (IVI:25.0), Swietenia

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macrophylla (IVI:15.9), Diospyros celebica (IVI:13.6), Delonix regia (IVI:13.5), and Hopea mengerawan (IVI:10.1) as dominant trees species.

Table 4. The Important Value Index of Each Species

No. Species Relative Frequency

Relative Density

Relative Dominancy

Important Value Index

1. Pterigota alata 21.3 26.6 87.4 135.3 2. Adenanthera pavonea 14.7 17.1 1.3 33.1 3. Paraserianthes falcataria 12.3 11.3 1.4 25.0 4. Swietenia macrophylla 7.7 7.7 0.5 15.9 5. Diospyros celebica 5.7 7.7 0.2 13.6 6. Delonix regia 4.4 5.9 3.2 13.5 7. Hopea mengerawan 5.7 4.1 0.3 10.1 8. Eucalypthus deglupta 4.4 4.4 1.1 9.9 9. Khaya anthotheca 5.7 3.2 0.3 9.2 10. Terminalia catappa 4.4 2.7 0.5 7.6 11. Hibiscus tiliaceus 4.4 2.3 0.1 6.8 12. Ceiba pentandra 1.0 1.4 3.2 5.6 13. Pometia pinnata 2.3 1.4 0.1 3.8 14. Casuarina Junghuhniana 1.0 0.9 1.1 3.0 15. Dipterocarpus cornutus 1.0 0.9 0.1 2.0 16. Azadirachta indica 1.0 0.5 0.2 1,7 17. Melaleuca leucadendron 1.0 1.0 0.02 1.5 18. Dalbergia latifolia 1.0 0.5 0.03 1.5 19. Alstonia scholaris 1.0 0.5 0.02 1.5 20. Ficus benyamina 1.0 0.5 0.02 1.5

The architectural branches of the dominant trees species identified that some of them have plagiotropis branch such as Pterigota alata, Paraserianthes falcataria, Hopea mengerawan, and Swietenia macrophylla. For identifying the canopy position in each layer, it can be illustrated by profile diagram as a canopy vertical structure expression. The profile diagram figure of the Bulaksumur Arboretum (Figure 1) that was observed in rectangular plot (20 m x 100 m), found 44 individual tree that consists of 8 species (Pterigota alata, Eucalypthus deglupta., Adenanthera pavonia, Hopea mengerawan, Melaleuca leucodendron, Paraserianthes falcataria, Khaya anthoteca and Dalbergia latifolia). Based on this figure, it can be interpreted that the first (emergent) canopy layer has been occupied by Pterigota alata, Paraserianthes falcataria, Eucalyptus deglupta and Hopea mengerawan. The position of emergent tree species create the discontinue canopy and make the tree open for the bird which will savely use for nesting or roosting. Adibrata and Pamudi (2007) identified that in Campus of Gadjah Mada University area about 177 emergent canopy trees that available for Ardea cinerea nesting and roosting, but based on the selection index, preferred canopy tree species for nesting are Sterculia foetida. Ficus elastica and Hopea mengerawan. The reason for selecting the canopy of tree for nesting are the canopy density: 1). The high density of canopy will protect the current of energy and material, so the bird in nest will be protected from predator viewing and their competitor, and from direct solar radiation and rain drop; 2). The canopy density as an important resource for the bird for getting cover.

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Relating to above report, in Bulaksumur Arboretum found that the Ardea cinerea made a nest in Pterigota alata (Photo 3), but Adibrata and Pambudi (2007) concluded that this tree species as one of unpreferred tree for nesting, although the number of tree of Pterigota alata that available for nesting about 22 trees then were used as nesting place are 9 trees. Another bird (Nycticorax nicticorax) found nesting in other tree such as Adenanthera pavonia (Photo 4). This performance showed that there was an ecological impact of the tree canopy relating to the used canopy tree for nesting by Ardea cinerea and other bird species, that is the architectural arrangement of branch which accommodated the nest building requirement. Adisubrata and Pambudi (2007) reported that there are 4 canopy tree species preferred for nesting site of Ardea cinerea (Ficus elastica, Sterculia foetida, Hopea mengerawan and Bombax sp.), but based on the availability of the canopy tree that feasible for nesting much more individual trees. Hutchinson (1947, cited by Park, 1980) explained that the restricted distribution of species to be largerly a function of temperature. Based on this statement, most of the trees canopy that arrange the Bulaksumur Arboretum are evergreen, so it might be as an ecological function of temperature for supporting the condition of canopy for nesting by Aredea cenerea.and other species of birds.

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Height of tree 30 m

4 x 3 x 10 x 5 x 2 x 6 x x 12 7 x 13 x 11x 1 x x 8 x 9

24 x 25 x 22 x 20 x 21 x 19 x 23 x 17 x 18 x 16 x 14 x 15 x

34 x 33 x 32 x 31 x 30 x 28 x 27 x 29x 26 x

40 x 39 x 38 x 37 x 35 x 36 x

44 x 43 x 42 x 41 x

0 20 m 40 m 60 m 80 m 100 m Figure #1: The Diagram Profile of Bulaksumur Arboretum, Yogyakarta, Indonesia

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Remark:

Pterigota alata Khaya anthoteca Adenanthera pavonia Paraserianther falcataria Dalbergia latifolia Melaleuca leucodendron Eucalypthus deglupta. Hopea mengerawan

Photo 3. The nest of Ardea cinerea in Pterigota alata canopy tree

Photo 4. The nest of Nycticorax nycticorax in Adenanthera pavonia canopy tree

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The tree canopy have been used as nesting site by the bird of Ardea cinerea and Nycticorac nycticorac could be identified in the field as listing in Table 5. There are 28.4% of the canopy trees of 8 species in Bulaksumur Arboretum used as nesting site and 15.8% is Pterigota alata, then followed by Adenanthera pavonea about 4.5% of the total trees. Table 5. Tree species as Nesting Site in Bulaksumur Arboretum

No. Tree species Diameter (cm)

Height (m)

Branch Canopy shape

1. 1). Pterigota alata 2). P.alata 3). P.alata 4). P.alata 5). P.alata 6). P.alata 7). P.alata 8). P.alata 9). P.alata 10). P.alata 11). P.alata 12). P.alata 13). P.alata 14). P.alata 15). P.alata 16). P.alata 17). P.alata 18). P.alata 19). P.alata 20). P.alata 21). P.alata 22). P.alata 23). P.alata 24). P.alata 25). P.alata 26). P.alata 27). P.alata 28). P.alata 29). P.alata 30). P.alata 31). P.alata 32). P.alata 33). P.alata 34). P.alata 35). P.alata

41.0 24.0 52.0 45.0 19.0 21.0 19.0 23.0 21.0 24.0 24.0 25.0 19.0 21.0 19.0 46.0 38.0 40.0 44.0 30.0 20.0 23.0 26.0 28.0 54.0 74.0 70.0 54.0 21.0 24.0 18.0 20.0 62.0 20.0 25.0

15 13 25 20 14 15 12 14 13 14 16 17 18 19 18 26 23 24 25 19 20 21 23 24 21 31 30 26 18 19 21 23 33 23 26

Plagiotroph Plagiotroph Plagiotroph Plagiotroph Plagiotroph Plagiotroph Orthotroph Plagiotroph Plagiotroph Plagiotroph Plagiotroph Plagiotroph Orthotroph Orthotroph Orthotroph Orthotroph Orthotroph Orthotroph Orthotroph Orthotroph Plagiotroph Plagiotroph Plagiotroph Plagiotroph Plagiotroph Plagiotroph Plagiotroph Plagiotroph Orthotroph Orthotroph Plagiotroph Plagiotroph Orthotroph Orthotroph Orthotroph

Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric Cylindric

2. 36). Paraserianthes falcataria 37). P.falcataria 38). P.falcataria 39). P.falcataria

40.0 40.0 28.0 32.0

20 20 16 18

Plagiotroph Orthotroph Orthotroph Orthotroph

Umbrella Umbrella Umbrella Umbrella

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No. Tree species Diameter (cm)

Heighti (m)

Branch Canopy shape

3. 40). Adenanthera pavonea 41). A.pavonea 42). A.pavonea 43). A.pavonea 44). A.pavonea 45). A.pavonea 46). A.pavonea 47). A.pavonea 48). A.pavonea 49). A.pavonea

42.0 24.0 21.0 20.0 21.0 24.0 23.0 26.0 21.0 23.0

15 25 22 21 20 21 21 23 20 21

Orthotroph Orthotroph Orthotroph Orthotroph Orthotroph Orthotroph Orthotroph Orthotroph Orthotroph Orthotroph

Umbrella Umbrella Umbrella Umbrella Umbrella Umbrella Umbrella Umbrella Umbrella Umbrella

4. 50). Eucalyptus deglupta 51). E.deglupta 52). E.deglupta

40.0 42.0 36.0

26 27 30

Orthotroph Orthotroph Orthotroph

Cone Cone Cone

5. 53). Hibiscus tiliaceus 54). H.tiliaceus

18.0 18.0

14 14

Orthotroph Orthotroph

Dome Dome

6. 55). Delonix regia 56). D.regia 57). D.regia 58). D.regia

22.0 63.0 54.0 19.0

16 21 19 15

Orthotroph Orthotroph Orthotroph Orthotroph

Dome Dome Dome Dome

7. 59). Pometia pinnata 21.0 16 Orthotroph Round 8. 60). Khaya anthoteca

61). K.anthoteca 62). K.anthoteca 63). K.anthoteca

14.0 16.0 15.0 19.0

14 14 14 15

Orthotroph Orthotroph Orthotroph Orthotroph

Round Round Round Round

Photo 5. Ardea cinerea roosting on the canopy of Paraserianthes falcataria

Other activity of Ardea cinerea in Bulaksumur Arboretum selected the top canopy for roosting. Based on the field observation showed that some tree species were used for roosting such as: Pterigota alata (Photo 3), Paraserianthes falcataria (Photo 5) and then, roosting on the canopy tree surrounding of Bulaksumur Arboretum such as Shorea

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zeilanica in front of Faculty of Forestry building and Ficus benyamina nearby Faculty of Pharmacy building. The Ardea cinerea and other bird species in Bulaksumur Arboretum were apparently not disturbed by the noise of the traffic-lane in this campus. So, this area must be comfortable for the sustainability of those species. Thomas and Hafner (2000) cited that the extent to which populations of Ardea cinerea can respond to habitat change remains poorly understood since few long-term data demonstrate the ability of natural populations to adapt to new environmental conditions. Unfortunately, those species create the negative impact as mentioned before, that is unpleasant odor of feces. This problem that should be handled for controlling the bird population, and if it possible to be moved to another area.

2. The Recommendation for Controlling the Bird Population Because of no one permit to shoot the bird in the Bulaksumur Arboretum and the Gadjah Mada University Campus members appreciated to conserve the bird species in their area, so it should be established a kind of research in permanent plot by managing the canopy structure. Some trees species in this arboretum used as nesting site and for roosting or resting, the requirement of this activities are high tree canopy and plagiotropic branch. Based on this condition, the recommendation can be suggested as follows: 1). Top canopy tree punning of emergent trees in Bulaksumur Arboretum Gadjah Mada

Univerity (such as Pterigota alata and Adenanthera pavonea) for avoiding the bird use as nesting site.

2). Creating the uncomfortable condition by disturbing the bird in order to move to other area. For this recommendation, it should be as collaborative action with the Zoo and Park of Gembira Loka Management for preparing the compensation area for migrating. Na’iem (2009, pers.comm) as the Dean of Faculty of Forestry Gadjah Mada University said that the Management of The Zoo and Park of Gembira Loka has offered the moving area for the Ardea cinerea and other bird in his arboretum. Based on this situation, it must be thought about the technical tool for driving the birds out from Bulaksumur Arboretum. The benefit of the Zoo and Park of Gembira Loka is predator availability for preying the juvenile that falling down from the nest, such as Monitor Lizard.

3). For implementing the controlling bird population should be organized by the integrated board which consists of several stakeholders that concern with the survival of Ardea cinerea and sustainability of the arboretum.

4). The long term research program can be conducted in this case by involving the student and the researcher/lecturer and the NGO members.

THE CONCLUSSION

Based on the conservation issues of the Ardea cinerea as protected bird species generally in Indonesia, it can be concluded that: 1). The Bulaksumur Arboretum created the positive ecological impact for the Ardea

cinerea live. It consists of 14 families wit 20 tree species (diameter ≥ 10 cm dbh) and the dominant trees with the important value index ≥ 10 were 7 species. All trees distributed vertically in 3 canopy layers. Several trees species used for nesting and roosting by Ardea cinerea because of the canopy shape, architectural branch and high (e.g. Pterigota alata, Adenanthera pavonea, Paraserianthes falcataria,

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Swietenia macrophylla, Hopea mengerawan, Eucalyptus deglupta, Khaya anthoteca and Delonix regia).

2). For controlling the bird population should be established the permanent plots for monitoring and investigating the effect of branch pruning of tree canopy on the population size changes of Ardea cinerea. The Bulaksumur Arboretum is managed by natural based. So, if the research will be conducted, it should be involved some stakeholders who concern with this bird species survival and sustainability of the arboretum under supervise of integrated board.

3). For driving out the Ardea cinerea and other bird species from the Bulaksumur Arboretum should be prepared the compensation area such as the arboretum of the Zoo and Park of Gembira Loka in Yogyakarta city.

ACKNOWLEDMENT

By writing this paper let me expressing my appreciation to many persons who supporting in the field activity and the fulfilling the secondary data, also supporting the budget for traveling. First, the Rector of Gadjah Mada University, the Dean of Faculty of Forestry Gadjah Mada University, the Chairman of Dendrology Laboratory; second, the students of Faculty of Forestry Gadjah Mada University (Tulus Pambudi, Bany Medi A., Angga Sigit P., and Muhammad Iqbal); third, the field photographer group (Yuno E.Putranto, Bayu A.Arifianto and Yanuar Widiassari). Finally, thank you for the Conference Committee who approved this paper for presenting in the 5th International Canopy Conference titled Forest Canopy: conservation, climate change and sustainable use. In Bangalore, India, October, 25-31, 2009.

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