8.4.1 Traditional Agroforestry of Pekarangan
Pekarangan is the traditional and privately owned home garden, and an integrated system with an intimate relationship among human, plants, and animals. It is well known that this garden has multiple functions, such as conservation of genetic resources, soil, and water, crop production, and sociocultural relationships in the rural area. It is thought that pekarangan is an optimal and sustainable land use with high productivity in tropical regions (Arifin 1998). Arifin and Arifin (2010) stated that pekarangan is a kind of traditional agroforestry practice that is found in rural and agricultural landscapes beside kebun campuran (mixed gardens) and kebun talun (forest gardens). The design and structure depends on local and ecological knowledge of the surrounding communities. The survey showed that the western part of Indonesia practices agro-silvo-fishery, as there are many water resources, and in contrast, the eastern part of Indonesia practices agro-silvo-pastura because of lack of water (Arifin et al. 2008a).
Pekarangan fulfills an ecological function in that its multilayered vegetation structure resembles that of natural forests and offers habitats and niches for a diverse community of wild plants and animals (Albuquerque et al. 2005; Karyono 1990). This study has confirmed the performance of pekarangan at the smallest scale. Those provisions are the contribution of pekarangan for nutrition intake, income, wealth assets, family status, access to credit, control of production, and product marketing.
Some research, particularly pekarangan biodiversity based on urbanized vegetation structures, was conducted in the landscape ecological unit of Ciliwung and Cisokan Watershed, which covers the Bogor-Puncak-Cianjur (BOPUNJUR) region (Arifin 2004; Arifin et al. 2001). Species richness was elucidated for pekarangan starting from the upper stream reaches to the downstream portion of the watersheds. Landscape structure in the traditional agroforestry of the pekarangan system has horizontal and vertical diversity (Arifin et al. 1998). Based on plant function, horizontal diversity has been classified into eight groups: ornamental plants, fruit plants, vegetable crops, starchy crops, medicinal plants, spices crops, industrial plants, and others (Arifin 1998). It is found that the size of pekarangan and percentage of plant canopy coverage are larger from the upper stream reaches to downstream. However, the highest averages of individual numbers per pekarangan
Table 8.2 Number of species and individual numbers per pekarangan in Cianjur Watershed
aOnly trees and shrubs with dbh > 2.5 cm were measured Pekarangan size, size of the open space area
Source: Arifin et al. (2001); Arifin (2004)
and species diversity index were found in the middle streams of Cianjur watershed (Table 8.2). This area is a transition zone between the lowland and mountainous areas (Arifin et al. 2001).
Based on plant function, the lower parts of watershed have a smaller ornamental plant ratio (Table 8.3). Fruit plants were found in the downstream predominantly (30.4 %), followed by others (17.1 %), such as fuel wood species, wood for handicrafts material, and wood for building materials (Arifin 2004).
In the BOPUNJUR region, changes of pekarangan plant diversity were studied along an urban-rural continuum as well as along an elevation gradient. The vegetation structure and composition of 115 pekarangans in six villages were investigated to determine the urbanization effects (Arifin et al. 1998). The six villages differed in urbanization level: one is a rural village, three are characterized as intermediately urbanized, and two are urban villages. In each pekarangan, both ornamental and crop plants were inventoried. Pekarangan sizes ranged from 30 m2 to 4,000 m2; the average size was 270 m2. In total, 440 plant species were grown in the 115 pekarangans; about half the species were ornamentals. The number of species in a pekarangan varies according to local physical circumstances, ecological characteristics of plants, kinds of animal species, and socioeconomic and cultural factors. Plant species numbers varied largely among the 115 pekarangans studied. Average species number per pekarangan were not markedly different between the rural, the intermediate, and the urban pekarangans (Arifin 1998 and Arifin et al. 1998). However, the average number of nonornamental plant species per pekarangan was markedly higher in rural than in urban pekarangan. The proportion of ornamental plants from total species increased with a higher level of urbanization (40 % in rural to 70 % in urban). Pekarangan size decreased continuously from rural to urban areas. In many densely populated tropical regions, pekarangans appear to be the last forest-like islands surrounded by increasingly extended, uniform staple crop fields. In these areas, pekarangans with their multilayered vegetation structure serve as an important habitat for wild flora and fauna. Pekarangans fulfill not only important ecological but also many social and cultural functions (Kehlenbeck et al. 2007).
Table 8.3 Ratio of species number by pekarangan plant function in Cianjur Watershed
Source: Arifin (2004)
Furthermore, a homestead plot survey on Java (Arifin et al. 2008b) was conducted in 144 pekarangan samples from three provinces: West, Central, and East Java provinces. The pekarangan samples covered two watershed units per province. Pekarangan size was divided into two groups: smaller than 120 m2 (small pekarangan) and between 120 and 400 m2 (moderate-size pekarangan). The total species number is 196 (Table 8.4), consisting of ornamental plants (103 species), fruit plants (29 species), vegetable crops (21 species), medicinal plants (13 species), spice crops (9 species), industrial plants (9 species), other plants (7 species), and starchy crops (5 species).