Dampak Perkebunan Sawit terhadap Keanekaragaman Herpetofauna dan Mamalia di Kebun KGP dan CNG Kalimantan Barat

Abstract

Kelapa sawit (Elaeis guineensis) adalah salah satu komoditas tanaman perkebunan yang mengalami perkembangan luasan sangat pesat di Indonesia selama 25 tahun terakhir. Besarnya perkembangan luasan kebun kelapa sawit berimplikasi terhadap besarnya kontribusi komoditas perkebunan sebagai penyumbang devisa negara terbesar di Indonesia. Seiring dengan perkembangan luasan perkebunan kelapa sawit semakin besar di Indonesia, mengundang berbagai tudingan bahwa perkebunan kelapa sawit berdampak negatif terhadap kelestarian keanekaragaman hayati khususnya jenis herpetofauna dan mamalia. Oleh karena itu penelitian ini penting dilakukan untuk membuktikan apakah perkebunan kelapa sawit berdampak terhadap keanekaragaman jenis herpetofauna dan mamalia. Penelitian ini bertujuan menduga dampak perubahan tutupan lahan dari semak belukar menjadi perkebunan kelapa sawit terhadap keanekaragaman jenis, komposisi jenis, menduga besaran kehilangan dan perolehan jenis mamalia herpetofauna dan menganalisis distribusi jenis herpetofauna dan mamalia berdasarkan tutupan lahan di perkebunan kelapa sawit. Pengambilan data dilakukan di Kebun Kencana Graha Permai (KGP) dan Kebun Cahaya Nusa Gemilang (CNG), Ketapang Provinsi Kalimantan Barat pada Juli-Agustus 2018. Pengambilan data jenis herpetofauna menggunakan metode Visual Encounter Survey (VES) yang dikombinasikan dengan Metode Strip Transect. Jenis mamalia menggunakan Metode Strip Transect pada tutupan lahan sebelum dan setelah menjadi perkebunan kelapa sawit. Data dianalisis dengan menggunakan analisis, jumlah jenis (S), indeks keanekaragaman jenis Shannon-Wiener (H’), indeks Kekayaan Margalef (Dmg), indeks kemerataan jenis (E). Pendugaan kehilangan dan perolehan jenis herpetofauna dan mamalia dianalisis dengan indeks Kesamaan Komunitas Sorensen (IS). Analisis guild pakan berdasarkan kategori jenis karnivora, herbivora dan omnivora. Analisis sebaran jenis herpetofauna dan mamalia menggunakan Arc GIS 10.3 yang dilakukan secara deskriptif berdasarkan pemetaan sebaran spasial. Hasil penelitian perubahan tutupan lahan dari semak belukar menjadi perkebunan kelapa sawit, untuk jenis herpetofauna kebun KGP berdampak terhadap selisih dampak meningkat 8 jenis, sedangkan kebun CNG selisih dampak meningkat 4 jenis. Dampak terhadap keanekaragaman jenis kebun KGP meningkat (1,39), kekayaan jenis meningkat (1,39), sedangkan kebun CNG selisih dampak keanekaragaman jenis meningkat (0,39), kekayaan jenis meningkat (0,44). Dampak terhadap kemerataan jenis kebun KGP menurun (0,09), sedangkan pada kebun CNG nilai dampak bernilai 0. Dampak perubahan tutupan lahan dari semak belukar menjadi perkebunan kelapa sawit pada jenis mamalia kebun KGP tidak berdampak, sedangkan pada kebun CNG selisih dampak meningkat 1 jenis. Dampak terhadap keanekaragaman jenis kebun KGP meningkat (0,24), kekayaan jenis menurun (0,19), sedangkan untuk kebun CNG selisih dampak keanekaragaman jenis meningkat (0,01), kekayaan jenis menurun (0,18). Dampak terhadap kemerataan jenis kebun KGP meningkat (0,35), sedangkan dampak pada kebun CNG menurun (0,15). Pendugaan kehilangan untuk jenis herpetofauna kebun CNG terjadi kehilangan 2 jenis dan perolehan 6 jenis, sedangkan kebun KGP kehilangan 2 jenis dan perolehan 10 jenis. Pendugaan kehilangan untuk jenis mamalia kebun CNG terjadi kehilangan 1 jenis dan perolehan 2 jenis, sedangkan kebun KGP kehilangan 1 jenis dan perolehan 1 jenis akibat perubahan tutupan lahan menjadi kebun kelapa sawit. Hasil analisis distribusi jenis herpetofauna kebun KGP didominasi jenis Hylarana erythraea dan Chalcorana raniceps famili Ranidae, dan pada kebun CNG didominasi jenis Pulchrana baramica famili Ranidae. Distribusi jenis mamalia kebun KGP dan CNG didominasi jenis Callosciurus notatus famili Sciuridae dan Rattus tiomanicus famili Muridae.

Oil palm (Elaeis guineensis) is one of the plantation crop commodities that has experienced very rapid development in Indonesia over the last 25 years. The significant development of the oil palm plantation area has implications for the large contribution of plantation commodities as the largest contributor to Indonesia's foreign exchange. Along with the development of oil palm plantations in Indonesia, there are various accusations that oil palm plantations hurt the preservation of biodiversity, especially herpetofauna and mammal species. Therefore, this research is essential to prove whether oil palm plantations impact the diversity of herpetofauna and mammal species. This study aims to estimate the impact of land cover changes from shrubs to oil palm plantations on species diversity, species composition, estimate the loss and gain of herpetofauna mammals and analyze the distribution of herpetofauna and mammal species based on land cover in oil palm plantations. Data collection was carried out at Kencana Graha Permai (KGP) and Cahaya Nusa Gemilang (CNG), Ketapang, West Kalimantan Province in July-August 2018. Data collection for herpetofauna types used the Visual Encounter Survey (VES) method combined with the Strip Transect method. Types of mammals using the Strip Transect method on the land cover before and after becoming an oil palm plantation. The data were analyzed using the number of species (S), the Shannon-Wiener species diversity index (H'), the Margalef Wealth index (Dmg), and the species evenness index (E). The loss and gain of herpetofauna and mammal species were analyzed using the Sorensen Community Similarity index (IS). Feed guild analysis based on carnivorous, herbivorous and omnivorous type categories. Analysis of the distribution of herpetofauna and mammal species using Arc GIS 10.3 was carried out descriptively based on spatial distribution mapping. The research results on changes in land cover from shrubs to oil palm plantations on the herpetofauna type in KGP plantations had an impact on increasing the difference in impact by 8 species, while in CNG plantations the difference in impact increased by 4 species. The impact on the diversity of species in KGP plantations increased (1,39), species richness increased (1,39), while the difference in the impact of species diversity increased (0,39), and species richness increased (0,44). The impact on the evenness of KGP plantation types decreased (0,09), while in CNG plantations, the impact value was 0. The impact of changes in land cover from shrubs to oil palm plantations on mammal species in KGP plantations had no impact, while in CNG plantations, the difference in impact increased by 1 species. The impact on the diversity of species in KGP plantations increased (0,24), and species richness decreased (0,19), while the difference in the impact of species diversity increased (0,01), decreased species richness (0,18). The impact on the evenness of KGP plantation types increased (0,35), while the impact on CNG plantations decreased (0,15). The estimation of the loss of herpetofauna species in CNG plantations resulted in the loss of 2 species and the gain of 6 species, in comparison the KGP plantations lost 2 species and the gain of 10 species. Estimating the loss of mammal species in CNG plantations resulted in the loss of 1 species and gain of 2 species, while the KGP plantation lost 1 species and the gain of 1 species due to changes in land cover to oil palm plantations. The results of the analysis of the distribution of herpetofauna species in KGP were dominated by the Hylarana erythraea and Chalcorana raniceps Ranidae families and CNG plantations were dominated by the Pulchrana baramica Ranidae families. The analysis of the distribution of mammal species in KGP and CNG were dominated by Callosciurus notatus Sciuridae families and Rattus tiomanicus Muridae families.