Tropics
Online ISSN : 1882-5729
Print ISSN : 0917-415X
ISSN-L : 0917-415X
23 巻, 2 号
選択された号の論文の5件中1~5を表示しています
INTRODUCTION
ORIGINAL ARTICLES
  • Roberto Porro, Alejandro Lopez-Feldman, Jorge W. Vela-Alvarado, Lourde ...
    2014 年 23 巻 2 号 p. 47-62
    発行日: 2014/09/01
    公開日: 2014/09/01
    ジャーナル フリー
    Findings from a survey on sources of income and land allocation outcomes of 578 households from 26 communities with diverse ethnic composition at distinct environmental settings in Ucayali (Peruvian Amazon) are used to contrast livelihood strategies featuring high forest and high agriculture dependency, examining whether agricultural intensification can be linked to lower deforestation. A typology of households based on their land use allocation profile was used to assess current and cumulative cleared land. Recently cleared areas by households oriented to perennials, semi-perennials and pastures were similar to those focusing on annual crops. Multiple class comparisons provided evidence that land use intensification is not associated to land sparing. Near 40% of the households’ annual income was derived from forests, followed by agriculture (25%), wages (17%) and livestock (11%). Income structure was used to determine high dependency on forests and on agriculture, featured by respectively 24% and 17% of the households, while 10% relied mostly on wages and/or businesses and half of them had a balanced income structure. Results indicate different expressions of the criticality of forest products, highlighting livelihood strategies based on the integration of income sources. Moreover, the study shows that despite the relevance of forest products, mestizo and indigenous livelihoods heavily depend on agriculture. Policy interventions aimed at environmental conservation and economic development will only be successful when strengthening the integration between agriculture and forest use featured by different social groups in the Amazon.
  • Kanae Ishimaru, Shigeo Kobayashi, Sayaka Yoshikawa
    2014 年 23 巻 2 号 p. 63-71
    発行日: 2014/09/01
    公開日: 2014/09/01
    ジャーナル フリー
    In Brazil, the movement of landless peasants and poor people excluded from the urban labor market to occupy uncultivated lands for agricultural production is widespread. We examined whether settling on occupied land enables landless peasants to improve their livelihood or not, and which agricultural practices should be implemented at the initial stage of migration in order to secure production sufficient for subsistence, by comparing households in two settlements that were at different time periods of the migration process. The survey results suggest that the selection and combination of crop species is an important factor for producing both sales income and subsistence. Providing crop species-specific information essential to generating sales income and subsistence—e.g., harvest season, fruiting age, and market value—may increase the chances of alleviating poverty.
  • Masahiro Ichikawa, Arbert Ricse, Julio Ugarte, Shigeo Kobayashi
    2014 年 23 巻 2 号 p. 73-82
    発行日: 2014/09/01
    公開日: 2014/09/01
    ジャーナル フリー
    One of main factors identified as explaining forest loss and degradation in the Selva (the Peruvian Amazon) is the migration of people from the Sierra (Andes highlands), where agricultural conditions are severe, to forest areas in the Selva in search of new land. This paper aims at clarifying the characteristics and process of migration based on interviews with local people near Pucallpa, Ucayali Department, where forest loss and degradation has advanced in recent decades. In the study area, forest loss and degradation progressed by commercial logging after construction of a road connecting between Lima and Pucallpa in 1943. After logging, stock-farming companies and immigrants entered the area, and land uses other than high forest have been expanding. Today, the study area is occupied by people who have immigrated since the 1960s. Many of them earned income by logging until the 1980s, while today almost of them make a livelihood by agriculture, stock farming, or tree planting. As a result of these economic activities, there are substantial areas of mixed shrubs and grass in the study area today. This paper clarifies two points. First, the majority of immigrants were born not in the Sierra, but in the Selva, for instance as part of the expanding population in the Departments of San Martin and Amazonas. The main stream of migration is from parts of the Selva where immigrants had started reclamation in earlier days to other parts of the Selva with still abundant forests (such as the study area). Second, most migrants were not born in a rural area, but in Pucallpa, a developing urban area in the Selva. Pucallpa is also an important place for step migrants who stayed there for a while and worked temporarily before immigrating to the study area. The urban area has gained an important role in migration to forests in the Selva as a place of birth of migrants and for its function in step migration.
  • Shigeo Kobayashi, Manuel Soudre, Arberto Ricse
    2014 年 23 巻 2 号 p. 83-90
    発行日: 2014/09/01
    公開日: 2014/09/01
    ジャーナル フリー
    Secondary succession or facilitation processes carried out at sites established for rehabilitating abandoned pastures and degraded forests (prurmas) are instrumental in their return to original forest status. An understanding of these secondary succession processes contributes to the rehabilitation of degraded forest ecosystems and to the livelihoods of local communities, and aids in conserving biodiversity. We studied secondary succession in mixed species plantations that were established to rehabilitate abandoned land. The initial vegetation in these abandoned pastures and croplands was grassland composed of three dominant species: Rottboellia exaltata, Imperata brasiliensis, and Brachyaria decumbens. After tree planting and weeding had been carried out, the site was first invaded by R. exaltata and Baccharis floribunda. These two species, which depend solely on sexual and not vegetative reproduction, facilitated secondary succession and elevated species diversity by enabling subsequent invasion by several species. By contrast, B. decumbens, I. brasiliensis, and Hyparrhenia rufa depend mainly on vegetative reproduction involving rhizomes and tillers, and subsequent invasion by other species was relatively less in stand types dominated by these three species. We found that further adequate rehabilitation techniques were necessary for the respective vegetation types.
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