Forest Loss in Papua New Guinea:     How much does subsistence        agriculture contribute?Jamie FullerPhD Student in Ec...
Papua New Guinea and relative areaIntroduction            Data and Methods   Results   Discussion
…    Culturally and biologically diverse:    •~800 distinct languages and tribal cultures    •Contains 5-10% of world biod...
Food and agricultural Organization (FAO) Forestry Department, website 2012Introduction                Data and Methods    ...
Degradation                                     Deforestation                                        Potential Change     ...
PNG Population                        8Population (millions)                        7                        6            ...
Primary forest                             Fallow                                                           Hard to distin...
Recent ecological research:                                     •     Minor disturbance to ecosystem Perceptions of swidde...
Kamiali, PNG                                  Kamiali village-Quantify how the land has changed-Understand the decisions i...
Satellite imagery:•Landsat: 1992, 2003, 2010 (end of Sept-early Oct)   •Cloud mask (LEDAPS by NASA)   •Tasseled cap   •Wet...
1992                      2003                                 2010                          Cloud                        ...
Agriculture conversion                        1992 to 2003                                   2003 to 2010                 ...
Forest conversion                         1992 to 2003                               2003 to 2010                         ...
Mixed cover conversion                    1992 to 2003                                 2003 to 2010                       ...
Land use is dynamic and rates of change             vary over time• Agricultural expansion is not directly correlated  to ...
Mechanistic pathways in land change                                                                 (Lambin et al. 2003)1)...
Conclusion• Agricultural expansion did not occur to the same  extent as national levels   – Suggesting that agricultural e...
Questions ?Jamie FullerPhD Student in EcologyColorado State UniversityJamie.fuller@colostate.eduhttp://warnercnr.colostate...
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2012 ASPRS Track, Forest cover loss in Papua New Guinea: How much does subsistence agriculture contribute?, Jamie Fuller

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Deforestation rates in Papua New Guinea (PNG) are more rapid than the Brazilian Amazon. This high rate of forest degradation and loss largely impacts scientific understanding of biodiversity in PNG. While many factors have been linked to deforestation and land degradation in PNG, the relationship between agricultural practices and deforestation have not been fully examined. The effects of agricultural expansion have been overestimated in some areas due to population growth, the negative perception of swidden agriculture (slash-and-burn), and difficulties in discerning agriculture from logged areas in aerial imagery. To examine how swidden agricultural strategies contribute to land cover changes a coastal village was selected. This village, Kamiali, has thwarted logging industry advances and maintained primary forest cover. To assess agricultural and land use changes participatory research was conducted and responses were linked to land cover change via aerial imagery.
Temporal analyses of satellite imagery revealed that cultivated area in Kamiali has increased by 9% between 1992 and 2010 despite an estimated population growth of 63%. Thus, agricultural strategies other than expansion were employed to sustain the population. Interviews supported intensification strategies, which included 1) shortened fallows, 2) an increase in crops planted per area, and 3) new cultivar and crop introductions. The intensification was supported with brightness-wetness index, a tasseled cap band subtraction analysis. Image differencing then suggested a temporal increase in crop coverage and density. These results show that subsistence agriculture has influenced land cover changes, but has not been a major contributor to deforestation rates in Kamiali.

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2012 ASPRS Track, Forest cover loss in Papua New Guinea: How much does subsistence agriculture contribute?, Jamie Fuller

  1. 1. Forest Loss in Papua New Guinea: How much does subsistence agriculture contribute?Jamie FullerPhD Student in EcologyColorado State UniversityJamie.fuller@colostate.eduhttp://warnercnr.colostate.edu/~jdfuller
  2. 2. Papua New Guinea and relative areaIntroduction Data and Methods Results Discussion
  3. 3. … Culturally and biologically diverse: •~800 distinct languages and tribal cultures •Contains 5-10% of world biodiversity and only 0.5% land surfaceIntroduction Data and Methods Results Discussion
  4. 4. Food and agricultural Organization (FAO) Forestry Department, website 2012Introduction Data and Methods Results Discussion
  5. 5. Degradation Deforestation Potential Change Combined forest degradation and deforestation Between 1972 and 2002 - 24% forest loss (9% degraded and 15% deforested) (Shearman et al. 2009; Shearman and Bryan 2011)Introduction Data and Methods Results Discussion
  6. 6. PNG Population 8Population (millions) 7 6 5 4 3 2 1 0 1980 1990 2000 2010Introduction Data and Methods Results Discussion
  7. 7. Primary forest Fallow Hard to distinguish: •Size and distribution •Heterogeneous cover •Seasonal variation •Fallow periods Results in over estimation (Mertz et al. 2009;Slashed garden plot Messerli et al. 2009; Schmidt-Vogt et al. 2009 3nd year crops Fox et al. 2000) Introduction Data and Methods Results Discussion
  8. 8. Recent ecological research: • Minor disturbance to ecosystem Perceptions of swidden: • Increased edge habitat• Simple, naïve and destructive • Fallow regeneration • Runoff and erosion lessened• Practiced by indigenous and poor – (Ziegler et al 2009, Fox et al. 2000) populations• Governments began to ban it to Transition to more permanent reduce deforestation agriculture causes: • Above and below ground carbon decline • Native plant diversity decreases • Fewer crop varieties • Economic vulnerability & losses when crops fail or markets change • Land sparing vs. land sharing (Ziegler et al. 2011; Sturgeon 2005; Cramb et al. 2009; Perfecto and Vandermeer 2010)Introduction Data and Methods Results Discussion
  9. 9. Kamiali, PNG Kamiali village-Quantify how the land has changed-Understand the decisions influencing land use change-Identify the drivers of change 65 km from Lae, PNG Ocean access only (no roads) WMA area: 500 km2 Current Population: ~850 Subsistence livelihoodIntroduction Data and Methods Results Discussion
  10. 10. Satellite imagery:•Landsat: 1992, 2003, 2010 (end of Sept-early Oct) •Cloud mask (LEDAPS by NASA) •Tasseled cap •Wetness-Brightness Difference Index (WBDI) •Helmer et al. 2009 •Unsupervised classification Participatory research: (Conducted July 2011) •Participatory mapping •Structured household surveys •Resource use interviews •e.g. fishing, gardening, forest resources •Oral history with elders •Economic organization exercise Introduction Data and Methods Results Discussion
  11. 11. 1992 2003 2010 Cloud Water Cloud Water Riparian Ag. Riparian Riparian Ag. 9% 11% 12% Ag. 11% 18% 18% Mixed 10% Mixed Mixed 12% 16% Forest Forest Forest 67% 59% 57%Introduction Data and Methods Results Conclusion
  12. 12. Agriculture conversion 1992 to 2003 2003 to 2010 =17% 3% 6% =27% 4% 8% 28% 16% 45% Loss to riparian Loss to forest 7% Loss to mixed 38% Ag. - no change Ag. gain 45% Introduction Data and Methods Results Discussion
  13. 13. Forest conversion 1992 to 2003 2003 to 2010 =23% =20% 10% 5% 8% 4% 17% 12% 4% 10% Loss to riparian Loss to mixed Loss to ag. 68% Forest - no change 63% Forest gain Introduction Data and Methods Results Discussion
  14. 14. Mixed cover conversion 1992 to 2003 2003 to 2010 3% =34% 2% =32% 16% 15% 47% Loss to riparian 48% 15% Loss to forest 15% Loss to ag. Mixed - no change 19% 20% Mixed gain Introduction Data and Methods Results Discussion
  15. 15. Land use is dynamic and rates of change vary over time• Agricultural expansion is not directly correlated to population growth• Other subsistence strategies were employed Time span 1990-2000 2000-2010 Population 1.4% per year 8% per year Time span 1992-2003 2003-2010 Agriculture 2.6% per year 0.14% per yearIntroduction Introduction Data and Methods Data and Methods Results Results Discussion Discussion
  16. 16. Mechanistic pathways in land change (Lambin et al. 2003)1) Cultural and land tenure 4) Economic influences systems • Modern goods & conveniences • Smaller plot sizes • Cash economy • Shorter fallows 5) Demographics • Increased # of crops per plot •Population increase2) Natural variability •Shifts • Changes in weather/climate •In/Out migration • Pest increases 6) Technological changes3) Institutional changes • Access to different varieties & • Support from NGO crops • WMA status • Fishing equipment changes • Fishing cooperative 7) Globalization • Visiting researchers • Local and global fish markets • The Jones’s Introduction Introduction Data and Methods Data and Methods Results Results Discussion Discussion
  17. 17. Conclusion• Agricultural expansion did not occur to the same extent as national levels – Suggesting that agricultural expansion may be overestimated in other regions of PNG – Intensified agriculture• These results improved our understanding of the rate of land change in this conservation area. – Ecological importance: pressures from logging, mining and climate changes are likely to increaseIntroduction Introduction Data and Methods Data and Methods Results Results Discussion Discussion
  18. 18. Questions ?Jamie FullerPhD Student in EcologyColorado State UniversityJamie.fuller@colostate.eduhttp://warnercnr.colostate.edu/~jdfuller

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