[Ecosystem's soil conservation function and its spatial distribution in Lancang River Basin, Southwest China].

Based on the RUSLE model, this paper analyzed the ecosystem's soil conservation function and its spatial distribution in Lancang River Basin. This Basin could be one of the regions having the highest ecosystem' s soil conservation capability in China, with an annual ecosystem's soil conservation amount being 2.36 x 10(10) t x a(-1) and the soil conservation amount per unit area being 1453.72 t x a(-1) per hectare. The total amounts of the N, P, and K conserved in soils were 5.74 x 10(7), 3.07 x 10(7), and 3.75 x 10(8) t x a(-1), respectively, and presented an increasing trend from upstream to downstream. Among the ecosystems in the Basin, forest ecosystem had the highest soil conservation capability, followed by grassland and farmland, while desert ecosystem had the lowest one. The soil conservation capability of the ecosystems was linearly increased with the increase of vegetation coverage. Averagely, a 10% increment in the vegetation coverage could result in a 35.3% increment in soil conservation capability. To rationally increase the vegetation coverage by reliable ecosystem management based on local conditions would make good effect in preventing soil erosion and maintaining soil nutrients in the Basin.

[Evolvement of ecological footprint model representing ecological carrying capacity].

Ecological footprint (EF) is an important index of ecological carrying capacity. The original EF model is excellent in simplicity, aggregation, comparability, and lifelikeness in presenting results, but short in predictability, configuration, and applicability. To overcome these shortcomings, many researches were conducted to modify and promote the EF model, and developed it from static with single time scale to diversified ones, which included: 1) time series EF model, 2) input-output analysis based EF model, 3) integrated assessment incorporated EF model, 4) land disturbance degree based EF model, and 5) life cycle analysis based EF model, or component EF model. The function of EF as a measurement of ecological carrying capacity was significantly improved, but its accuracy and integrality still need to be advanced.

[Seasonal dynamics of ecosystem services of grassland in Qinghai-Tibetan Plateau].

Based on the theory of ecosystem services and by using RS and GIS techniques, the ecosystem services of grassland in Qinghai-Tibetan Plateau were analyzed and evaluated, with growth season as time unit. The results showed that the service of supplying biomass presented an up-down-up trend, and the peaks appeared in May and September. Its main affecting factors were PAR, soil moisture condition, and underground biomass. The service of carbon accumulation and oxygen release also presented up-down-up trend, which was related to the supplied biomass and its formation. As for the services of holding soil nutrients and water, the former had a peak in May, while the latter presented staggered variation due to the different water consumption characters of herbages at their different growth stages.