People's livelihood in several Himalayan regions largely depends on collection,use,and trade of medicinal plants.Traditional use is generally not a problem,but commercial gathering of selected species to meet incr...People's livelihood in several Himalayan regions largely depends on collection,use,and trade of medicinal plants.Traditional use is generally not a problem,but commercial gathering of selected species to meet increasing national and international demand can result in over-exploitation.Sustainable management of medicinal plants requires a clear understanding of the respective roles,responsibilities and viewpoints of the various stakeholders involved.Through personal interviews and group discussions,this study aimed at investigating the views of two stakeholder groups on use,trade and conservation of medicinal plants in the Rasuwa district of Nepal.Local people and district and national organizations agreed that medicinal plants are collected for a combination of commercial and personal uses.Perceptions on market availability differed significantly:100 % of the respondents from district and national organizations saw markets as easily available,against only 36 % for local people.This could explain why medicinal plants were perceived by local people to contribute less to income generation than to livelihood improvement.Different viewpoints were also expressed concerning the status of medicinal plants in the district:81 % of the respondents from district and national organizationsconsidered that medicinal plants were threatened,compared to only 28 % for local people.Despite this disparity,both stakeholder groups agreed upon potential threats to medicinal plants:over-harvesting;habitat loss due to land-use change and deforestation;and over-grazing by livestock.Several challenges were identified regarding sustainable management of medicinal plants,such as ambiguous policies;lack of resources,information and infrastructures;habitat degradation;and over-exploitation.Despite these challenges,respondents agreed that the medicinal plants sector offers huge opportunities in the Rasuwa district,given resource availability,community awareness and motivation,and the priority given to the sector by governments and other agencies.Proper collaboration,communication and coordination among stakeholders are needed to grab these opportunities.展开更多
Background: Cumulative impacts of wildfires and forest harvesting can cause shifts from closed-crown forest to open woodland in boreal ecosystems. To lower the probability of occurrence of such catastrophic regime shi...Background: Cumulative impacts of wildfires and forest harvesting can cause shifts from closed-crown forest to open woodland in boreal ecosystems. To lower the probability of occurrence of such catastrophic regime shifts,forest logging must decrease when fire frequency increases, so that the combined disturbance rate does not exceed the Holocene maximum. Knowing how climate warming will affect fire regimes is thus crucial to sustainably manage the forest. This study aimed to provide a guide to determine sustainable forest harvesting levels, by reconstructing the Holocene fire history at the northern limit of commercial forestry in Quebec using charcoal particles preserved in lake sediments.Methods: Sediment cores were sampled from four lakes located close to the northern limit of commercial forestry in Quebec. The cores were sliced into consecutive 0.5 cm thick subsamples from which 1 cm3 was extracted to count and measure charcoal particles larger than 150 microns. Age-depth models were obtained for each core based on accelerator mass spectroscopy(AMS) radiocarbon dates. Holocene fire histories were reconstructed by combining charcoal counts and age-depth models to obtain charcoal accumulation rates and, after statistical treatment,long-term trends in fire occurrence(expressed as number of fires per 1000 years).Results: Fire occurrence varied between the four studied sites, but fires generally occurred more often during warm and dry periods of the Holocene, especially during the Holocene Thermal Maximum(7000–3500 cal. BP), when fire occurrence was twice as high as at present.Conclusions: The current fire regime in the study area is still within the natural range of variability observed over the Holocene. However, climatic conditions comparable to the Holocene Thermal Maximum could be reached within the next few decades, thus substantially reducing the amount of wood available to the forest industry.展开更多
文摘People's livelihood in several Himalayan regions largely depends on collection,use,and trade of medicinal plants.Traditional use is generally not a problem,but commercial gathering of selected species to meet increasing national and international demand can result in over-exploitation.Sustainable management of medicinal plants requires a clear understanding of the respective roles,responsibilities and viewpoints of the various stakeholders involved.Through personal interviews and group discussions,this study aimed at investigating the views of two stakeholder groups on use,trade and conservation of medicinal plants in the Rasuwa district of Nepal.Local people and district and national organizations agreed that medicinal plants are collected for a combination of commercial and personal uses.Perceptions on market availability differed significantly:100 % of the respondents from district and national organizations saw markets as easily available,against only 36 % for local people.This could explain why medicinal plants were perceived by local people to contribute less to income generation than to livelihood improvement.Different viewpoints were also expressed concerning the status of medicinal plants in the district:81 % of the respondents from district and national organizationsconsidered that medicinal plants were threatened,compared to only 28 % for local people.Despite this disparity,both stakeholder groups agreed upon potential threats to medicinal plants:over-harvesting;habitat loss due to land-use change and deforestation;and over-grazing by livestock.Several challenges were identified regarding sustainable management of medicinal plants,such as ambiguous policies;lack of resources,information and infrastructures;habitat degradation;and over-exploitation.Despite these challenges,respondents agreed that the medicinal plants sector offers huge opportunities in the Rasuwa district,given resource availability,community awareness and motivation,and the priority given to the sector by governments and other agencies.Proper collaboration,communication and coordination among stakeholders are needed to grab these opportunities.
基金Financial support was provided by the Natural Sciences and Engineering Research Council of Canada and by the CNRS (Paleo2, INSU)
文摘Background: Cumulative impacts of wildfires and forest harvesting can cause shifts from closed-crown forest to open woodland in boreal ecosystems. To lower the probability of occurrence of such catastrophic regime shifts,forest logging must decrease when fire frequency increases, so that the combined disturbance rate does not exceed the Holocene maximum. Knowing how climate warming will affect fire regimes is thus crucial to sustainably manage the forest. This study aimed to provide a guide to determine sustainable forest harvesting levels, by reconstructing the Holocene fire history at the northern limit of commercial forestry in Quebec using charcoal particles preserved in lake sediments.Methods: Sediment cores were sampled from four lakes located close to the northern limit of commercial forestry in Quebec. The cores were sliced into consecutive 0.5 cm thick subsamples from which 1 cm3 was extracted to count and measure charcoal particles larger than 150 microns. Age-depth models were obtained for each core based on accelerator mass spectroscopy(AMS) radiocarbon dates. Holocene fire histories were reconstructed by combining charcoal counts and age-depth models to obtain charcoal accumulation rates and, after statistical treatment,long-term trends in fire occurrence(expressed as number of fires per 1000 years).Results: Fire occurrence varied between the four studied sites, but fires generally occurred more often during warm and dry periods of the Holocene, especially during the Holocene Thermal Maximum(7000–3500 cal. BP), when fire occurrence was twice as high as at present.Conclusions: The current fire regime in the study area is still within the natural range of variability observed over the Holocene. However, climatic conditions comparable to the Holocene Thermal Maximum could be reached within the next few decades, thus substantially reducing the amount of wood available to the forest industry.
