Kauffman J Boone, Bernardino Angelo F, Ferreira Tiago O, Bolton Nicholas W, Gomes Luiz Eduardo de O, Nobrega Gabriel Nuto
Department of Fisheries and Wildlife Oregon State University Corvallis Oregon.
Department of Oceanography Federal University of Espírito do Santo Vitória ES Brazil.
Ecol Evol. 2018 May 4;8(11):5530-5540. doi: 10.1002/ece3.4079. eCollection 2018 Jun.
Mangroves of the semiarid Caatinga region of northeastern Brazil are being rapidly converted to shrimp pond aquaculture. To determine ecosystem carbon stocks and potential greenhouse gas emissions from this widespread land use, we measured carbon stocks of eight mangrove forests and three shrimp ponds in the Acaraú and Jaguaribe watersheds in Ceará state, Brazil. The shrimp ponds were paired with adjacent intact mangroves to ascertain carbon losses and potential emissions from land conversion. The mean total ecosystem carbon stock of mangroves in this semiarid tropical landscape was 413 ± 94 Mg C/ha. There were highly significant differences in the ecosystem carbon stocks between the two sampled estuaries suggesting caution when extrapolating carbon stock across different estuaries even in the same landscape. Conversion of mangroves to shrimp ponds resulted in losses of 58%-82% of the ecosystem carbon stocks. The mean potential emissions arising from mangrove conversion to shrimp ponds was 1,390 Mg COe/ha. Carbon losses were largely from soils which accounted for 81% of the total emission. Losses from soils >100 cm in depth accounted for 33% of the total ecosystem carbon loss. Soil carbon losses from shrimp pond conversion are equivalent to about 182 years of soil carbon accumulation. Losses from mangrove conversion are about 10-fold greater than emissions from conversion of upland tropical dry forest in the Brazilian Caatinga underscoring the potential value for their inclusion in climate change mitigation activities.
巴西东北部半干旱卡廷加地区的红树林正迅速转变为虾塘养殖。为了确定这种广泛的土地利用方式下的生态系统碳储量和潜在温室气体排放，我们测量了巴西塞阿拉州阿卡拉乌和雅瓜里贝流域8片红树林和3个虾塘的碳储量。这些虾塘与相邻的完整红树林配对，以确定土地转换造成的碳损失和潜在排放。在这片半干旱热带景观中，红树林生态系统的平均总碳储量为413±94 Mg C/公顷。两个采样河口之间的生态系统碳储量存在极显著差异，这表明即使在同一景观中，跨不同河口推断碳储量时也需谨慎。红树林转变为虾塘导致生态系统碳储量损失了58%-82%。红树林转变为虾塘产生的平均潜在排放量为1390 Mg CO₂e/公顷。碳损失主要来自土壤，占总排放量的81%。深度超过100厘米的土壤损失占生态系统总碳损失的33%。虾塘转换造成的土壤碳损失相当于约182年的土壤碳积累量。红树林转换造成的损失比巴西卡廷加地区高地热带干旱森林转换产生的排放量大约高10倍，这突出了将其纳入气候变化缓解活动的潜在价值。
