Beijing, China
November 26, 2009
by Shanshan Li, SciDev.Net
The number of China's rice varieties has dramatically decreased, raising fears about the country's food security and biodiversity.
China had 46,000 rice varieties in the 1950s, but this plummeted to just 1,000 in 2006, according to a Chinese study published in BioScience this month.
The research used a variety of environmental indicators — such as forest coverage and water quality — to examine China's progress since parties to the Convention on Biological Diversity agreed in 2002 to significantly reduce biodiversity loss by 2010.
It found that despite making progress with its forest resources, China needs a more integrated biodiversity strategy.
"A significant reduction of biodiversity loss — or even a halt of it — can be achieved only if biodiversity conservation is mainstreamed into national and sectoral strategies and action plans. The next decade is a critical period for China," the authors wrote.
According to the study, China's grasslands have declined by 15,000 square kilometres per year over the past 30 years, and previous research found than 90 per cent of China's grasslands are degraded.
But there is some good news. Water quality in marine ecosystems has improved by more than four per cent per year from 2001 to 2007. The area of China's forests has increased from 13 per cent to 18 per cent in 2003, and forest growing stock — the volume of trees in an area that have more than a certain diameter at chest height — has increased by over 40 per cent.
"Biodiversity is increasing in China's forests," the study said.
Earlier this month, the State Forest Administration of China published its plan to adapt to climate change, proposing that China's forest coverage should increase to 20 per cent by 2010.
Bao-Rong Lu, a professor at China's Fudan University, told SciDev.Net: "The huge decrease [in rice yields] is a result of the extensive cultivation of a few genetically improved modern varieties that are high-yielding and pest-resistant."
"In addition, the farming style of monoculture — with only a few dominant varieties covering a huge area — will lead to a vulnerable agro-ecosystem."
Lu said that genebanks and nurseries could boost conservation but have their limitations, such as seeds not being able to adapt to environments after being frozen for long periods of time.
"The role of agriculture extension workers and scientists as active partners of farmers is also very important in the conservation of rice genetic diversity," added Lu.
Link to abstract in BioScience
China's Progress Toward the Significant Reduction of the Rate of Biodiversity Loss
Abstract: In 2002, parties to the Convention on Biological Diversity adopted a decision “to achieve by 2010 a significant reduction of the current rate of biodiversity loss.” Comprehensive assessment of the progress toward this “significant reduction” is rare at the national level. We therefore developed national indicators and time-series data sets to evaluate whether China had made progress toward the 2010 biodiversity target, and found that considerable progress has been made: Forest resources have increased stably since 1989, the integrity of marine ecosystems has improved since 1997, water quality has remained stable, and desertified land is less extensive than it used to be as a result of various conservation initiatives. However, trends toward the loss of grasslands, threatened species, and genetic resources were not effectively checked. It is imperative that China undertake a more active and integrated strategy for biodiversity conservation to stem projected increases in wastewater discharges, nutrient loading, invasive alien species, and climate change.
水稻品种的减少凸显了中国生物多样性的差距
中国的水稻品种显著下降,引起了对该国粮食安全水平和生物多样性现状的担忧。
根据一份由中国研究人员发表于本月（11月）号BioScience杂志上的研究报告，中国的水稻品种在上世纪50年代曾达46，000种，但在最近的几十年间迅速下降，2006年只有1000种。
这一研究使用森林覆盖、水质等一系列环境指标来评估中国在恢复生物多样性方面所取得的进展。中国是生物多样性公约的缔约国之一。该公约的各个缔约方在2002年同意到2010年显著减少生物多样性流失。
研究结果显示，虽然中国的森林覆盖率增速飞快,但仍需要更系统的保护生物多样性的策略。
报告说：“除非保护生物多样性的工作成为中国国家战略规划的主要部分，生物多样性降低甚至消失的情况才有可能显著放缓甚至消失。而未来10年将是中国让所有的利益攸关方参与保护其丰富而独特的生物多样性的关键时期。”
研究报告指出，在过去的30年中，中国的草原面积正以每年15，000平方公里的速度下降。而过去的研究曾发现，90%的中国草场正在退化。
除了坏消息，报告中也有一些好消息。2007年，海洋生态系统的水质比2001年提高了4%。森林覆盖率从13%增加到了2003年的18%，而林木蓄积量则增加了超过40%。研究者们说：“中国的森林生物多样性正在增加。”
本月早些时候，国家林业局发布了《应对气候变化林业行动计划》。计划中提到，2010年中国的森林覆盖率要达到20%。
而对于水稻品种数目的下降，复旦大学教授卢宝荣告诉本网站：“栽培水稻品种多样性的大规模减少是因为大规模推广栽种少数几种高产、优质的品种。而这种只栽培单一水稻品种的耕种模式将增加农业生态系统的脆弱性。”
卢认为，种质库等措施对水稻品种多样性的保存有一定作用，但这种保护是静态保护,使之与其原产地的生态环境产生了隔离,这将导致这些材料失去其在原产地生态环境下可能发生的新的遗传变异或继续进化的机会。
他还说：“农业推广人员和科学家与农民的更密切的合作对保持稻种遗传资源的多样性同样至关重要。”
链接到BioScience的摘要
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