This article analyzes the importance of non use values in the management of natural resources with a model of imperfect competition.By constucting a framework of duopolistic exploiters,the incorporation of non use v...This article analyzes the importance of non use values in the management of natural resources with a model of imperfect competition.By constucting a framework of duopolistic exploiters,the incorporation of non use values based on self interest and altruistic motives appears to be significant for determining the degree of inefficiency caused by the problem of common property at the non cooperative Nash equilibrium.It is found that when the non use value placed by the altruist exploiter is bounded by that placed by the pure self interest exploiter,the effect of market power is dominated by the effect of common exploitation.In this case,the exploiters' harvesting strategy will response in the same direction to the change of each other's harvesting at the non cooperative Nash equilibrium.In contrast,when the non use value placed by the altruist is substantially larger or smaller than that placed by the self interest exploiter,one exploiter's increase in harvesting will lead to a decrease in harvesting of the other exploiter at the non cooperative Nash equilibrium.展开更多
We tested the hypothesis that introduced populations may have higher resource capture ability and utilization efficiency than native ones of invasive plants. We compared ecophysiological traits including maximum photo...We tested the hypothesis that introduced populations may have higher resource capture ability and utilization efficiency than native ones of invasive plants. We compared ecophysiological traits including maximum photosynthetic rate (Pmax), apparent quantum yield (Q), specific leaf area (SLA), photosynthetic energy use efficiency (PEUE), photosynthetic nitrogen use efficiency (PNUE), water use efficiency (WUE), mass-based and area-based leaf construction cost (CCmass and CCarea), and mass-based and area-based leaf nitrogen concentration (Nmass and Narea) between native (Argentina) and introduced (USA) populations of two varieties (North Apa and South Apo) of Alternanthera philoxeroides under common garden conditions in China. For Apo and Apa, Pmax, Q, Nmass and WUE were not significantly different between native and introduced populations;introduced populations had significantly lower SLA and lower CCmass but significantly higher Narea and CCarea than native ones. For Apa, the introduced populations showed significantly lower PEUE and lower PNUE while for Apo, PEUE and PNUE were not significantly different between native and introduced populations. The results indicated that introduced populations of A. philoxeroides do not show higher resource capture ability and resource utilization efficiency than their native ones in the common garden experiment, suggesting that these traits may not necessarily contribute to successful invasion of invasive plants.展开更多
文摘This article analyzes the importance of non use values in the management of natural resources with a model of imperfect competition.By constucting a framework of duopolistic exploiters,the incorporation of non use values based on self interest and altruistic motives appears to be significant for determining the degree of inefficiency caused by the problem of common property at the non cooperative Nash equilibrium.It is found that when the non use value placed by the altruist exploiter is bounded by that placed by the pure self interest exploiter,the effect of market power is dominated by the effect of common exploitation.In this case,the exploiters' harvesting strategy will response in the same direction to the change of each other's harvesting at the non cooperative Nash equilibrium.In contrast,when the non use value placed by the altruist is substantially larger or smaller than that placed by the self interest exploiter,one exploiter's increase in harvesting will lead to a decrease in harvesting of the other exploiter at the non cooperative Nash equilibrium.
文摘We tested the hypothesis that introduced populations may have higher resource capture ability and utilization efficiency than native ones of invasive plants. We compared ecophysiological traits including maximum photosynthetic rate (Pmax), apparent quantum yield (Q), specific leaf area (SLA), photosynthetic energy use efficiency (PEUE), photosynthetic nitrogen use efficiency (PNUE), water use efficiency (WUE), mass-based and area-based leaf construction cost (CCmass and CCarea), and mass-based and area-based leaf nitrogen concentration (Nmass and Narea) between native (Argentina) and introduced (USA) populations of two varieties (North Apa and South Apo) of Alternanthera philoxeroides under common garden conditions in China. For Apo and Apa, Pmax, Q, Nmass and WUE were not significantly different between native and introduced populations;introduced populations had significantly lower SLA and lower CCmass but significantly higher Narea and CCarea than native ones. For Apa, the introduced populations showed significantly lower PEUE and lower PNUE while for Apo, PEUE and PNUE were not significantly different between native and introduced populations. The results indicated that introduced populations of A. philoxeroides do not show higher resource capture ability and resource utilization efficiency than their native ones in the common garden experiment, suggesting that these traits may not necessarily contribute to successful invasion of invasive plants.
