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Climate Change and Managed Ecosystems - Chapter 10

Các hệ sinh thái đất than bùn được đặc trưng bởi sự tích tụ các chất hữu cơ trong đất và, nếu sau Joosten và định nghĩa Clark's1 có ít nhất 30 cm than bùn với hàm lượng hữu cơ tối thiểu là 30%, sau đó vùng đất than bùn bao gồm hơn 4 triệu km2 - Khoảng 3% bề mặt đất của trái đất. Gần 70% diện tích đất than bùn này nằm trong các vùng phương bắc Canada và Nga. Canada một mình chứa chỉ hơn 1.200.000 km2 than bùn. Vùng đất than bùn là đáng kể mà họ cung cấp một sự. | 10 Peatlands Canada s Past and Future Carbon Legacy D.H. Vitt CONTENTS 10.1 Introduction.201 10.2 Limitations on Carbon Sequestration in Boreal Peatlands.203 10.3 The Ecology of Boreal Peat Accumulation.204 10.3.1 Bog Accumulation.205 10.3.2 Poor Fen Accumulation.205 10.3.3 Rich Fen Accumulation . 205 10.4 Northern Peatlands Sinks or Sources of Carbon .206 10.5 Potential Climatic Effects on Peatland Form and Vegetation.207 10.6 Permafrost Melting in the Boreal Forest.209 10.7 Global Climate Change vs. Cumulative Disturbance.210 10.8 Mitigation.211 Acknowledgments.213 References.213 10.1 INTRODUCTION Peatland ecosystems are characterized by the accumulation of organic matter in soil and if following Joosten and Clark s1 definition of having at least 30 cm of peat with a minimum organic content of 30 then peatlands cover over 4 million km2 about 3 of the Earth s land surface. Nearly 70 of this peatland area lies in the boreal regions of Canada and Russia. Canada alone contains just over 1 200 000 km2 of peat. Peatlands are significant in that they provide a wide diversity of ecosystem services not the least of which is the accumulation of large stores of carbon. Joosten and Clark1 estimated that since 1800 10 to 20 of the world s peatlands have been lost but it has been the view of many that Canada s peatlands remain in pristine condition undisturbed by human activities.2 However as we will see this is certainly not the case. Globally wetlands especially peatlands represent a large carbon stock with estimates varying from 200 to 860 Pg Petagrams of carbon see for example 201 2006 by Taylor Francis Group LLC 202 Climate Change and Managed Ecosystems w Yt ham 2 B xlin 3 4 QirA-fo 5 DacE zif- ol 6 LT V11 nlab Ata zif- ol 7 A bnta A ata4 A ĩíiTì ỈYÍ10 8 Gorham Bohn Sjors Post et al. Houghton et al. Armentano and Menges and Markov et al.9 . Generally carbon-iich peatland soils are thought to represent about one third of the world s soil carbon yet cover only about 3 of .