Wildfire, soil erosion and the risk to aquatic resources: evidence from the burnt Evrotas River basin, southern Peloponnese, Greece.

希腊最近的野火吞噬了20万公顷的土地，其中包括伯罗奔尼撒半岛的17.3万公顷农村土地。超过50%的受影响地区是森林或自然保护区，约40%是农田。据报道，截至今年9月，希腊发生了120多起重大火灾，而去年全年只有52起，这主要是由于持续高温达到46摄氏度。这些事件提供了一个独特的机会，以评估野火和随后的土壤侵蚀对水生资源（生态系统健康和供水）构成的风险。在这方面，本提案描述了一个快速反应的实地和实验室研究方案，以评估火灾后土壤侵蚀和沉积物的直接风险，并将养分输送到易发生火灾的地中海景观内的水道。PI最近对澳大利亚燃烧水供应集水区的研究说明了在地中海背景下集水区管理者可能面临的潜在问题。这项工作表明，相当于密集耕种的农田的营养浓度可能会在野火后被输送到溪流中。在严重火烧迹地，由于坡面水文过程和土壤结构的变化，火烧土侵蚀动力学发生了根本性的改变。后者也可能影响衍生河流沉积物中的养分供应，对水生生境和水质产生长期影响。对于严重烧毁的地中海景观，没有数据支持这一假设。这些数据必须在火灾后立即对土壤特性产生影响的证据消失之前收集，从而为在不确定的未来气候中评估集水区管理办法提供数据。

Recent wildfires in Greece engulfed 200,000 hectares of land including 173,000 hectares of rural land in the Peloponnese peninsula. More than 50% of the affected area was forest or nature reserve and around 40% was farmland. Over 120 major fires were reported in Greece by September of this year compared to 52 for the whole of last year largely due to a record period of sustained high temperatures up to 46 degrees C. These events present a unique opportunity to evaluate the risk that wildfire and subsequent soil erosion pose to aquatic resources (ecosystem health and water supply). In this context, this proposal describes a rapid-response field- and laboratory-based research programme to evaluate the immediate post-fire risk of soil erosion and sediment and nutrient delivery to water courses within fire-prone Mediterranean landscapes. The PI's recent research in Australian burnt water supply catchments illustrates the potential problems that might be faced by catchment managers in this Mediterranean context. This work has shown that nutrient concentrations equivalent to those from intensively farmed agricultural land may be delivered to streams following wildfire. The erosion dynamics of burnt soil are altered radically in severely burnt landscapes due to changes in hillslope hydrological processes and soil structure. The latter is also likely to affect nutrient availability in derived fluvial sediment with long-term implications for aquatic habitat and water quality. There are no data to support this hypothesis for severely burnt Mediterranean landscapes. These data must be collected before evidence of the immediate post-fire impacts on soil properties is lost thereby providing data to evaluate catchment management options in an uncertain climatic future.