Ecosystem functions in forests can vary significantly after disturbance, depending on changes in vegetation structure during succession and soil biophysical characteristics. We examined streamflow regulation, water storage and soil protection functions in small catchments covered by evergreen temperate rain forests, developed over volcanic ash soils, in southern South America. Our aims were to understand the differences in ecosystem functioning among catchments representing different forest stages following human disturbance, from scrubland to old-growth forest condition. In these catchments (n = 3 per condition), we assessed and compared eco-hydrological functions over 21 months. In old-growth (OG) forest catchments, streamflow for the entire study period averaged 2102 ± 110 mm, followed by secondary forest (SF) catchments with an average of 1770 ± 284 mm and finally scrub catchments (CH) with 1684 ± 267 mm. Evapotranspiration showed higher values in SF catchments (643 mm), followed by CH catchments (612 mm) and OG catchments (346 mm). OG and CH catchments had the lowest sediment export in streamflow, without statistical difference between them, while SF catchments had the highest sediment concentrations in all seasons of the year. Principal component analysis revealed that soil physical properties, vegetation structure and catchment morphometry were all relevant to explain the differences among the three forest successional stages compared. We validate the hypotheses that streamflow regulation and soil water storage capacity are greatly enhanced in old-growth forests, while the soil protection function is maximized in both early (bamboo-dominated) and advanced forest stages.

干扰后，森林的生态系统功能可能会发生很大变化，具体取决于演替过程中植被结构的变化和土壤生物物理特征。我们研究了南美南部由火山灰土壤覆盖的常绿温带雨林覆盖的小流域的水流调节，储水和土壤保护功能。我们的目的是了解代表人类扰动后不同森林阶段的流域之间的生态系统功能的差异，从灌木丛到旧林。在这些流域（n =每个条件3个），我们评估并比较了21个月内的生态水文功能。在旧林（OG）森林集水区，整个研究期间的平均流量为2102±110毫米，其次是次生林（SF）集水区的平均流量为1770±284毫米，最后是灌木集水区（CH）的流量为1684±267毫米。蒸散显示SF流域（643毫米），CH流域（612毫米）和OG流域（346毫米）更高。OG和CH流域的泥沙流出口量最低，两者之间无统计学差异，而SF流域在全年所有季节的泥沙浓度最高。主成分分析表明，土壤物理性质，植被结构和流域形态均与解释三个森林演替阶段之间的差异有关。我们验证了以下假设：老龄林中的流量调节和土壤蓄水能力大大增强，而早期（竹子为主）和高级森林阶段的土壤保护功能均得到了最大化。