Multiple abiotic and biotic factors, mainly the amount and seasonality of precipitation, fire regime, soil properties and species adaptation strategies, have been invoked to explain the existence of the tropical savanna–humid forest transition. We explored the rainfall variables that influence the probability of forest or savanna occurring in north-west South America, specifically monthly precipitation and the mean and maximum duration of wet and dry spells, defined as the number of consecutive wet (dry) days.

中文翻译：

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连续干湿日对南美洲西北部森林-稀树草原边界的影响

多种非生物和生物因素，主要是降水量和季节性、火灾状况、土壤特性和物种适应策略，已被用来解释热带稀树草原-湿润森林过渡的存在。我们探索了影响南美洲西北部森林或热带稀树草原出现概率的降雨变量，特别是月降水量和平均和最长干湿期持续时间，定义为连续湿（干）天数。