Quantifying Killing of Orangutans and Human-Orangutan Conflict in Kalimantan, Indonesia

Human-orangutan conflict and hunting are thought to pose a serious threat to orangutan existence in Kalimantan, the Indonesian part of Borneo. No data existed prior to the present study to substantiate these threats. We investigated the rates, spatial distribution and causes of conflict and hunting through an interview-based survey in the orangutan's range in Kalimantan, Indonesia. Between April 2008 and September 2009, we interviewed 6983 respondents in 687 villages to obtain socio-economic information, assess knowledge of local wildlife in general and orangutan encounters specifically, and to query respondents about their knowledge on orangutan conflicts and killing, and relevant laws. This survey revealed estimated killing rates of between 750 and 1800 animals killed in the last year, and between 1950 and 3100 animals killed per year on average within the lifetime of the survey respondents. These killing rates are higher than previously thought and are high enough to pose a serious threat to the continued existence of orangutans in Kalimantan. Importantly, the study contributes to our understanding of the spatial variation in threats, and the underlying causes of those threats, which can be used to facilitate the development of targeted conservation management

Penentuan Debit Harian Menggunakan Pemodelan Rainfall Runoff GR4J untuk Analisa Unit Hidrograf pada DAS Citarum Hulu

Abstrak. Penelitian ini mengkaji pemodelan rainfall-runoff menggunakan metode GR4J (Ge´nie Rural a` 4 parame`tres Journalier) pada Daerah Aliran Sungai (DAS) Citarum hulu. Dalam studi ini digunakan input data berupa data hujan harian dan data evapotranspirasi potensial yang hasilnya dikalibrasi menggunakan data debit pengamatan harian. Dalam studi ini akan dicari nilai optimum dari parameter pemodelan GR4J yang menghasilkan simpangan atau error yang paling kecil. Ada dua tahapan dalam pemodelan ini, yaitu: kalibrasi model dan validasi model. Kalibrasi model menggunakan data lima tahun pertama dan validasi model menggunakan data lima tahun kedua. Untuk menghitung simpangan yang terjadi digunakan metode Nash-Sutcliffe Coefficient (NS) dan metode Relative Volume Error (RVE). Pemodelan ini mengoptimasi empat parameter bebas berupa Kapasitas Maksimum Production Store (X1), Koefisien Perubahan Air Tanah (X2), Kapasitas Maksimum Routing Store (X3), dan Waktu Puncak Ordinat Unit Hidrograf (X4). Parameter waktu puncak ordinat unit hidrograf (X4) digunakan untuk keperluan studi banjir berupa analisa unit hidrograf yang menggunakan metode linear reservoir cascade. Kajian dilakukan dengan memanfaatkan DAS Sungai Citarum yang merupakan suatu DAS terukur. Kalibrasi menggunakan data pengamatan di stasiun debit Nanjung dan berdasarkan data pengamatan di beberapa stasiun hujan di dalam DAS. Hasil dari kajian ini menyimpulkan bahwa data lima tahun pertama memiliki parameter yang hampir sama dengan data lima tahun kedua. Hal ini menunjukan pola curah hujan dandebit tidak mengalami perubahan yang berarti. Abstract. This research is to study the rainfall-runoff modeling using GR4J (Ge´nie Rural a` 4 parame`tres Journalier) on Citarum Hulu River Basin. In this study, the data input of daily rainfall and potential evapotranspiration are used, and the result will calibrated with the observed data of daily discharge. In this study, the optimum value of GR4J model parameters will be observed to get the smallest error deviation. There are two stages in this modeling. Firstly is model calibration and secondly is model validation. Model calibration uses the first of five years of data input and model validation uses the following five years. The Nash-Sucliffe Coefficient (NS) and The Relative Volume Error (RVE) methods are used to obtain the error deviation. This study is intended to optimize four free parameters, there are the maximum capacity of production store (X1), the groundwater exchange coefficient (X2), the maximum capacity of routing store (X3), and the time base of unit hydrograph (X4). The last parameter (X4) is used to study flood discharge in the form of unit hydrograph analysis that uses linear reservoir cascade. This study uses gaged river basin, Citarum River Basin. Calibration uses the observed discharge data of Nanjung Station and based on the observed data of several rainfall stations inside the river basin. The result of this study shows that the first five years data has parameters quite similar with the second five years data. This shows rainfall and discharge pattern are not change significantly

Potential distribution area of orangutan in Central Kalimantan (yellow), West Kalimantan (purple) and East Kalimantan (green), and the village area boundaries within these regions.

<p>Potential distribution area of orangutan in Central Kalimantan (yellow), West Kalimantan (purple) and East Kalimantan (green), and the village area boundaries within these regions.</p

Crop raiding intensity in different villages across Kalimantan.

<p>High  =  reported conflict frequency every week; Medium  =  every month; Low  =  once a year or less frequently.</p