Gaveau D.L.A.,Stanford University |
Curran L.M.,Stanford University |
Paoli G.D.,Daemeter Consulting |
Carlson K.M.,Stanford University |
And 5 more authors.
Conservation Letters | Year: 2012
Several studies suggest that protected areas conserve forests because deforestation rates are lower inside than outside protected area boundaries. Such benefits may be overestimated when deforestation rates within protected areas are contrasted with rates in lands where forest conversion is sanctioned. Here, we reexamine protected area performance by disentangling the effects of land use regulations surrounding the 110,000 km2 protected area network in Sumatra, Indonesia. We compared 1990-2000 deforestation rates across: (1) protected areas; (2) unprotected areas sanctioned for conversion; and (3) unprotected production areas where commercial logging is permitted but conversion is not. Deforestation rates were lower in protected areas than in conversion areas (Mean: -19.8%; 95% C.I.: -29.7--10.0%; P < 0.001), but did not differ from production areas (Mean: -3.3%; 95% C.I.: -9.6-2.6%; P= 0.273). The measured protection impact of Sumatran protected areas differs with land use regulations governing unprotected lands used for comparisons. If these regulations are not considered, protected areas will appear increasingly effective as larger unprotected forested areas are sanctioned for conversion and deforested. In the 1990s, production areas were as effective as protected areas at reducing deforestation. We discuss implications of these findings for carbon conservation. © 2012 Wiley Periodicals, Inc. Source
Carlson K.M.,University of Minnesota |
Carlson K.M.,Yale University |
Carlson K.M.,Stanford University |
Curran L.M.,Yale University |
And 9 more authors.
Journal of Geophysical Research: Biogeosciences | Year: 2014
Oil palm plantation expansion into tropical forests may alter physical and biogeochemical inputs to streams, thereby changing hydrological function. In West Kalimantan, Indonesia, we assessed streams draining watersheds characterized by five land uses: intact forest, logged forest, mixed agroforest, and young (<3 years) and mature (>10 years) oil palm plantation. We quantified suspended sediments, stream temperature, and metabolism using high-frequency submersible sonde measurements during month-long intervals between 2009 and 2012. Streams draining oil palm plantations had markedly higher sediment concentrations and yields, and stream temperatures, compared to other streams. Mean sediment concentrations were fourfold to 550-fold greater in young oil palm than in all other streams and remained elevated even under base flow conditions. After controlling for precipitation, the mature oil palm stream exhibited significantly greater sediment yield than other streams. Young and mature oil palm streams were 3.9°C and 3.0°C warmer than the intact forest stream (25°C). Across all streams, base flow periods were significantly warmer than times of stormflow, and these differences were especially large in oil palm catchments. Ecosystem respiration rates were also influenced by low precipitation. During an El Niño-Southern Oscillation-associated drought, the mature oil palm stream consumed a maximum 21 g O2 m-2 d-1 in ecosystem respiration, in contrast with 2.8-±-3.1 g O2 m-2 d-1 during nondrought sampling. Given that 23% of Kalimantan's land area is occupied by watersheds similar to those studied here, our findings inform potential hydrologic outcomes of regional periodic drought coupled with continued oil palm plantation expansion. ©2014. American Geophysical Union. All Rights Reserved. Source