在人类占用净初级生产力(HANPP)等研究基础上,提出了净初级生产力(NPP)权衡假设,即生态系统供给、调节服务的权衡受到HANPP各组分分配比例的影响;基于NPP权衡假设构建了生产生态协同提升模式效果的分析框架。以西藏拉萨河流域白朗村为例...在人类占用净初级生产力(HANPP)等研究基础上,提出了净初级生产力(NPP)权衡假设,即生态系统供给、调节服务的权衡受到HANPP各组分分配比例的影响;基于NPP权衡假设构建了生产生态协同提升模式效果的分析框架。以西藏拉萨河流域白朗村为例,基于实地采样、监测数据,分析了生态修复前、协同提升及河谷种草模式下,白朗村的HANPP组分、空间格局,以及生产、生态功能(牲畜养殖数量、碳固定服务和空气净化服务)。结果表明:在实施生态修复前,白朗村共有牲畜15990羊单位,HANPP为35.0 g C/m^(2),占潜在NPP的13.8%,其中收获导致的HANPPharv占40.0%;生态系统空气净化服务为12.0 g SO_(2) m^(-2)a^(-1),碳固定服务为6245.4 g C m^(-2)a^(-1)。协同提升后,HANPP总量基本保持不变,但结构发生了变化,其中HANPPharv提高了4.2%,土地利用导致的HANPPluc降低了1.8%。同时,养殖牲畜数量增加6.3%,生态系统调节服务基本保持同一水平。在河谷种草模式下,HANPP总量相比实施生态修复前降低了67.0%,结构变化更加剧烈。HANPPharv增加了84.2%,为25.8 g C/m^(2);HANPPluc降低了167.0%,为-14.2 g C/m^(2)。牲畜数量大幅增加了2.2倍(35195.0羊单位);而空气净化服务也提高了15.1%(13.8 g SO_(2)m^(-2)a^(-1)),碳固定服务提高了5.0%(6560.1 g C m^(-2)a^(-1))。研究表明,NPP权衡假设可以为定量分析区域尺度生态系统服务权衡提供一定的理论支持,促进生产生态功能协同提升的生态修复模式优化。展开更多
Grazing exclusion is widely adopted in restoring degraded alpine grasslands on the Qinghai-Tibetan Plateau. However, its effectiveness remains poorly understood. In this study, we investigated the effects of grazing e...Grazing exclusion is widely adopted in restoring degraded alpine grasslands on the Qinghai-Tibetan Plateau. However, its effectiveness remains poorly understood. In this study, we investigated the effects of grazing exclusion on plant productivity, species diversity and soil organic carbon(SOC) and soil total nitrogen(STN) storage along a transect spanning from east to west of alpine meadows in northern Tibet, China. After six years of grazing exclusion, plant cover, aboveground biomass(AGB), belowground biomass(BGB), SOC and STN were increased, but species diversity indices declined. The enhancement of AGB and SOC caused by grazing exclusion was correlated positively with mean annual precipitation(MAP). Grazing exclusion led to remarkable biomass increase of sedge species, especially Kobresia pygmaea, whereas decrease of biomass in forbs and no obvious change in grass, leguminous and noxious species. Root biomass was concentrated in the near surface layer(10 cm) after grazing exclusion. The effects of grazing exclusion on SOC storage were confined to shallow soil layer in sites with lower MAP. It is indicated that grazing exclusion is an effective measure to increase forage production and enhance soil carbon sequestration in the studied region. The effect is more efficient in sites with higher precipitation. However, the results revealed a tradeoff between vegetation restoration and ecological biodiversity. Therefore, carbon pools recover more quickly than plant biodiversity in the alpine meadows. We suggest that grazing exclusion should be combined with other measures to reconcile grassland restoration and biodiversity conservation.展开更多
The net primary production （NPP） of grasslands in northeastern Asia was estimated using improved CASA model with MODIS data distributed from 2000 and ground data as driving variables from 2000 to 2005. Average annua...The net primary production （NPP） of grasslands in northeastern Asia was estimated using improved CASA model with MODIS data distributed from 2000 and ground data as driving variables from 2000 to 2005. Average annual NPP was 146.05 g C m^-2 yr^-1 and average annual total NPP was 0.32 Pg C yr^-1 in all grasslands during the period. It was shown that average annual grassland NPP in the whole northeastern Asia changed dramatically from 2000 to 2005, with the highest value of 174.80 g C m^-2 yr^-1 in 2005 and the lowest value of 125.65 g C m^-2 yr^-1 in 2001. On regional scale, average annual grassland NPP of 179.71 g C m^-2 yr^-1 in southeastern Russia was the highest among the three main grassland regions in the six years. Grasslands in northern China exhibited the highest average annual total NPP of 0.16 Pg C yr^-1 and contributed 51.42% of the average annual total grassland NPP in northeastern Asia. Grassland NPP in northeastern Asia also showed a clear seasonal pattern with the highest NPP occurred in July every year. Average monthly grassland NPP in southeastern Russia was the highest from May to August while average monthly grassland NPP in northern China showed the highest NPP before May and after August. The change rate distribution of grassland NPP between the former three years and the latter three years showed grassland NPP changed slightly between the two stages in most regions, and that NPP change rate in 80.98% of northeastern Asia grasslands was between -0.2 and 0.2. Grassland NPP had close correlation with precipitation and temperature, that indicates climate change will influence the grassland NPP and thus have a great impact on domestic livestock in this region in future.展开更多
文摘在人类占用净初级生产力(HANPP)等研究基础上,提出了净初级生产力(NPP)权衡假设,即生态系统供给、调节服务的权衡受到HANPP各组分分配比例的影响;基于NPP权衡假设构建了生产生态协同提升模式效果的分析框架。以西藏拉萨河流域白朗村为例,基于实地采样、监测数据,分析了生态修复前、协同提升及河谷种草模式下,白朗村的HANPP组分、空间格局,以及生产、生态功能(牲畜养殖数量、碳固定服务和空气净化服务)。结果表明:在实施生态修复前,白朗村共有牲畜15990羊单位,HANPP为35.0 g C/m^(2),占潜在NPP的13.8%,其中收获导致的HANPPharv占40.0%;生态系统空气净化服务为12.0 g SO_(2) m^(-2)a^(-1),碳固定服务为6245.4 g C m^(-2)a^(-1)。协同提升后,HANPP总量基本保持不变,但结构发生了变化,其中HANPPharv提高了4.2%,土地利用导致的HANPPluc降低了1.8%。同时,养殖牲畜数量增加6.3%,生态系统调节服务基本保持同一水平。在河谷种草模式下,HANPP总量相比实施生态修复前降低了67.0%,结构变化更加剧烈。HANPPharv增加了84.2%,为25.8 g C/m^(2);HANPPluc降低了167.0%,为-14.2 g C/m^(2)。牲畜数量大幅增加了2.2倍(35195.0羊单位);而空气净化服务也提高了15.1%(13.8 g SO_(2)m^(-2)a^(-1)),碳固定服务提高了5.0%(6560.1 g C m^(-2)a^(-1))。研究表明,NPP权衡假设可以为定量分析区域尺度生态系统服务权衡提供一定的理论支持,促进生产生态功能协同提升的生态修复模式优化。
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060700)Postdoctoral Science Foundation of China(No.2013M530716)
文摘Grazing exclusion is widely adopted in restoring degraded alpine grasslands on the Qinghai-Tibetan Plateau. However, its effectiveness remains poorly understood. In this study, we investigated the effects of grazing exclusion on plant productivity, species diversity and soil organic carbon(SOC) and soil total nitrogen(STN) storage along a transect spanning from east to west of alpine meadows in northern Tibet, China. After six years of grazing exclusion, plant cover, aboveground biomass(AGB), belowground biomass(BGB), SOC and STN were increased, but species diversity indices declined. The enhancement of AGB and SOC caused by grazing exclusion was correlated positively with mean annual precipitation(MAP). Grazing exclusion led to remarkable biomass increase of sedge species, especially Kobresia pygmaea, whereas decrease of biomass in forbs and no obvious change in grass, leguminous and noxious species. Root biomass was concentrated in the near surface layer(10 cm) after grazing exclusion. The effects of grazing exclusion on SOC storage were confined to shallow soil layer in sites with lower MAP. It is indicated that grazing exclusion is an effective measure to increase forage production and enhance soil carbon sequestration in the studied region. The effect is more efficient in sites with higher precipitation. However, the results revealed a tradeoff between vegetation restoration and ecological biodiversity. Therefore, carbon pools recover more quickly than plant biodiversity in the alpine meadows. We suggest that grazing exclusion should be combined with other measures to reconcile grassland restoration and biodiversity conservation.
基金Basic Research Project of the Ministry of Science and Technology,No.2007FY110300National Basic Research Program of China,No.2005CB724801
文摘The net primary production （NPP） of grasslands in northeastern Asia was estimated using improved CASA model with MODIS data distributed from 2000 and ground data as driving variables from 2000 to 2005. Average annual NPP was 146.05 g C m^-2 yr^-1 and average annual total NPP was 0.32 Pg C yr^-1 in all grasslands during the period. It was shown that average annual grassland NPP in the whole northeastern Asia changed dramatically from 2000 to 2005, with the highest value of 174.80 g C m^-2 yr^-1 in 2005 and the lowest value of 125.65 g C m^-2 yr^-1 in 2001. On regional scale, average annual grassland NPP of 179.71 g C m^-2 yr^-1 in southeastern Russia was the highest among the three main grassland regions in the six years. Grasslands in northern China exhibited the highest average annual total NPP of 0.16 Pg C yr^-1 and contributed 51.42% of the average annual total grassland NPP in northeastern Asia. Grassland NPP in northeastern Asia also showed a clear seasonal pattern with the highest NPP occurred in July every year. Average monthly grassland NPP in southeastern Russia was the highest from May to August while average monthly grassland NPP in northern China showed the highest NPP before May and after August. The change rate distribution of grassland NPP between the former three years and the latter three years showed grassland NPP changed slightly between the two stages in most regions, and that NPP change rate in 80.98% of northeastern Asia grasslands was between -0.2 and 0.2. Grassland NPP had close correlation with precipitation and temperature, that indicates climate change will influence the grassland NPP and thus have a great impact on domestic livestock in this region in future.
