Karakteristik habitat Burung Serak Tyto alba javanica (Gmel.) pemangsa tikus pada ekosistem persawahan di Kabupaten Kendal, Jawa Tengah

KUSWARDANI, Retna Astuti, Promotor Prof.Emeritus.Dr.Ir. Soeprapto Mangoendihardjo

2006 | Disertasi | S3 Ilmu Pertanian

Burung serak Tyto alba javanica (Gmel.) dikenal sebagai predator tikus yang handal di ekosistem perkebunan antara lain perkebunan sawit. Burung serak telah dicoba dilepaskan di ekosistem persawahan seperti di Malaysia, DIY, dan Jawa Tengah, untuk pengendalian hama tikus. Permasalahannya yakni tempat pelepasan yang tepat berupa habitat burung serak di ekosistem persawahan belum diketahui sehingga habitat itu perlu dikarakterisasi. Tujuan penelitian ini untuk mendeskripsi komponen utama habitat makro dan mikro burung serak di ekosistem persawahan yang meliputi pelindung, ruang, dan mangsa. Penelitian dilakukan di daerah Kabupaten Kendal, Propinsi Jawa Tengah, dari bulan Juli 2003 sampai dengan Agustus 2004, dengan metode survei. Wawancara terhadap 90 responden dilakukan di 50 lokasi pelepasan burung serak dan daerah sebarannya. Sistem Informasi Geografis (SIG) dipakai untuk pemetaan lokasi keberadaan sarang. Sementara itu kelimpahan pelet yang ditemukan di suatu wilayah dipakai sebagai indikator bahwa wilayah tersebut merupakan habitat burung serak. Sarang yang dihuni burung serak dengan keluarganya dipilih secara acak sebanyak 40 sarang, untuk studi tipe habitat makro dan mikro. Keragaman vegetasi dan penggunaan lahan pada kawasan jelajah (home range) radius 800 m dari sarang dideskripsi untuk menentukan tipe habitat makro, sedangkan kondisi fisik sarang diukur untuk menentukan tipe habitat mikro. Analisis komponen pelet (rambut, bulu, tulang, tengkorak, dan materi lainnya) dipakai sebagai dasar identifikasi jenis mangsa. Dalam kurun waktu sejak tahun 2000 sampai dengan 2004 di Kabupaten Kendal, burung serak mampu berkembang biak dan menyebar. Dari tahun 2000 sampai tahun 2002 burung serak dilepas di 50 lokasi. Pada tahun 2004 burung serak ditemukan berada di 108 lokasi dengan rincian 67,59% di dataran rendah (daerah pantai hingga 100 m dpl.) dan 32,41% di dataran tinggi (ketinggian lebih dari 100 hingga 500 m dpl.) dengan aneka tipe habitat. Habitat makro burung serak antara lain terdiri atas unsur pelindung, ruang, dan mangsa. Pada ekosistem persawahan karakteristik habitat makro burung serak ialah berupa kawasan sawah yang luas (10-50 ha), dan merupakan endemik serangan tikus dengan intensitas serangan tinggi, di sekitar areal sawah terdapat pepohonan untuk bertengger dan aktivitas lainnya, dan terdapat ruang untuk bersarang. Di dataran rendah komponen habitat makro meliputi sawah irigasi, pekarangan, ladang, kebun, semak, tambak, dan rawa, berturut-turut 61, 29, 4, 2, 2, 2, dan 0,18%. Di dataran tinggi komponen habitat makro meliputi kebun, sawah tadah hujan, pekarangan, sawah irigasi, semak, dan hutan, berturutturut 35, 34, 20, 6, 5, dan 0,34%. Luasan komponen habitat makro berkorelasi positip dengan kelimpahan pelet kecuali luasan hutan secara signifikan berkorelasi negatif dengan kelimpahan pelet, diduga burung serak cenderung tidak menyukai hutan. Karakteristik habitat mikro burung serak di ekosistem persawahan ialah berupa ruangan untuk bersarang yang terlindung dari hujan dan sinar matahari langsung dengan volume ruang bervariasi antara 0.08 - 1, 125 m3, suhu ruang minimum antara 20,75 - 24,250C dan maksimum antara 30,5 – 38,50C, tinggi sarang antara 3 – 14m dari permukaan tanah, sarang berada sejak di dekat areal sawah hingga jarak 725 m dari areal sawah. Bentuk sarang bervariasi; plafon bangunan (74,07%), pohon ((24, 07%), dan gupon (1,86%). Berbagai jenis mangsa burung serak yang ditemukan yakni tikus (89,95%), burung (5,09%),kelelawar (2,94%), dan lain-lain yakni tokek, katak, tupai dan cicak (2,02%). Serpihan tubuh serangga juga ditemukan di dalam pelet. Dari 89,95% jenis tikus yang ditemukan tersebut terdiri atas Rattus argentiventer (Robb & Kloss) 80,69%, Rattus norvegicus (Berkenhout.) 4,16%, Rattus rattus diardii(Jent) 3,79%, Bandicota indica(Bechst) 1,18%, dan Rattus tiomanicus (Miller) 0,13%.

The barn owl, Tyto alba javanica (Gmel.) is one of the important rodentpredator in the estate ecosystems for example in palm oil ecosystem. Use of the barn owl to control rats has been pioneered at several rice-field ecosystems in Malaysia, Bali, Central Java, and Special Territory of Jogjakarta. One of the substantial problem is that a right release-site in the rice-field ecosystems has never been known yet, there for, the barn owl habitats are necessary described. The research was aimed at describing the major components of macro and micro habitats of the barn owl in the rice-field ecosystems at which it comprises of the place, the cover, and the prey. The research was carried out in Kendal Regency, Province of Central Java, from July 2003 to August 2004 using survey method. An interview to 160 despondences was done in 50 localities of barn owl release site and its distribution areas. Geographic Information System (GIS) was used to map distribution of barn owl’s nests. Meanwhile, the abundance of pellet in any areas was used as an indicator for those areas are as a habitat of the barn owl. The occupied nests by the barn owl families as many as 40 nests were taken at random, to study the macro and micro habitat types. The vegetation diversity and land use in the home range at radius of 800 m from the nests were described to determine the macro habitat, while physical conditions of the nests were recorded to determine the micro habitat. Components of pellets (hair, feathers, skull, teeth, and other body ornaments) were analyzed to determine species of the barn owl prey. During time period of 2000 to 2004 the barn owl was able to multiply and spread in Kendal Regency. The barn owl was released at 50 sites in the regency during time - period of 2000 to 2002. In the year of 2004 the barn owl was found in 108 localities; 67,59% out of them were found in lowland areas (from close to seashore up to 100 m above sea level) and 32,41% out of them were found in upland areas ( more then 100 to 575 m above sea level), with various types of habitat. The macro habitat of the barn owl comprised of the place, the cover, and the prey. In the rice- field ecosystems, macro-habitat characteristics of the barn owl are a wide rice-field-area (10–50 hectares) at which it is an endemic rat infestation, at the surrounding rice-field-areas there are trees for perch and spaces for nesting. In the lowland areas components of the macro habitat are irrigated rice-fields, home gardens, unirrigated agricultural fields, estates, scrubs, coastal ponds, and marshes, with proportion of 61, 29, 4, 2, 2, 2, and 0,18%, respectively. In the highland areas components of macro habitat are estate, unirrigated ricefields, home gardens, irrigated rice fields, scrubs, and forest, with proposition of 35, 34, 20, 6, 5, and 0,34%, respectively. Area of the habitat components correlated positively with the abundance of pellets except for forest, it was observed that the forest area negatively correlated with abundance of pellet. It seemed that the forest tends to be not suitable for the barn owl. Micro-habitat characteristics of the barn owl in the rice-field ecosystem were a space for nesting which was protected from direct sunlight and rains, with various sizes of volume (0.08 to 1.125 m3), minimum temperature ranged from 20.75 to 24.25 0C and maximum temperature ranged from 30.5 to 38.5 0C, nest height from the land surface was about 3-14 m, distances between nest site and rice field were 0-725 m, nest types were 74,07% ceiling of buildings, 24,07% trees, and 1,86% nest boxes. The barn owl-preys were rats (89,95%), birds (5.09%), bats (2.94%), and others such as gecko, frog, squirrel, and house lizard (2.027%). It was also observed some insect fragments found on the pellets. Out of 89,95% of rats consisted of Rattus argentiventer (Robb & Kloss) 80,69%, Rattus norvegicus (Berkenhout.) 4,16%, Rattus rattus diardii (Jent) 3,79%, Bandicota indica(Bechst) 1,18%, and Rattus tiomanicus (Miller) 0,13%.

Kata Kunci : Ekosistem Persawahan, Burung Serak, Tikus Sawah dan Tikus Pohon