Global patterns and drivers of rainfall partitioning by trees and shrubs

Abstract

Spatiotemporal redistribution of incident rainfall in vegetated ecosystems results from the partitioning by plants into intercepted, stemflow, and throughfall fractions. However, variation in patterns and drivers of rainfall partitioning across global biomes remains poorly understood, which limited the ability of climate models to improve the predictions of biome hydrological cycle under global climate change scenario. Here, we synthesized and analyzed the partitioning of incident rainfall into interception, stemflow, and throughfall by trees and shrubs at the global scale using 2430 observations from 236 independent publications. We found that (1) globally, median levels of relative interception, stemflow, and throughfall accounted for 21.8%, 3.2%, and 73.0% of total incident rainfall, respectively; (2) rainfall partitioning varied among different biomes, due to variation in plant composition, canopy structure, and macroclimate; (3) relative stemflow tended to be driven by plant traits, such as crown height:width ratio, basal area, and height, while relative interception and throughfall tended to be driven by plant traits as well as meteorological variables. Our global assessment of patterns and drivers of rainfall partitioning underpins the role of meteorological factors and plant traits in biome‐specific ecohydrological cycles. We suggest to include these factors in climate models to improve the predictions of local hydrological cycles and associated biodiversity and function responses to changing climate conditions.

Efeitos da dinâmica pluviométrica na interceptação e precipitação interna em uma encosta com Floresta Atlântica no Parque Nacional da Tijuca, RJ, Brasil.

“…A análise espacial apontou diferença significativa entre as parcelas, com menor percentual interceptado no DV em comparação à BE, com um leve aumento na significância dessa diferença para os valores percentuais, comparado ao observado para os volumes interceptados: (%Int)P < (VInt)P. Ao comparar diferentes biomas do mundo, Yue et al (2021) indicaram o índice de área foliar como principal fator preditor para os percentuais de interceptação. Nossos dados corroboram o indicado por tais autores, uma vez que no DV há maior abertura de dossel, e que esta foi menor na BE (Miranda e Avelar, 2019).…”

“…Este resultado reflete o fato que as diferenças entre áreas são origin adas por aspectos da vegetação, diretamente influentes ao potencial de interceptação. Sendo fortemente influenciada pelo volume de chuva inicial, a diferença entre áreas perde relevância nas chuvas de maiores volumes (Arcova et al, 2020a;Yue et al, 2021), o que é demonstrado pela correlação mais forte entre as áreas para a variável precipitação interna (Tabela 2). Ou seja, dentre as variáveis dependentes avaliadas (interceptação em volume e percentuais, e precipitação interna), a precipitação interna é que apresenta menor variação espacial.…”

“…A chuva, ao entrar em contato com a vegetação de uma determinada área, pode seguir três rotas distintas: (i) ser captada e permancer armazenada (até evaporar) nos tecidos vegetais (interceptação); (ii) ser captada e fluir através dos tecidos de sustentação das plantas até o solo (fluxos de tronco); (iii) atravessar ou gotejar para o ambiente abaixo das copas (precipitação interna) (Livesley et al, 2014;Van Stan e Stubbins, 2018;Magliano et al, 2019;Arcova et al, 2020a;Paula et al 2020). Em termos de média global (diferentes biomas florestais e arbustivos), a interceptação pelas copas e os fluxos de tronco representam cerca 21.8% e 3.2% da precipitação incidente, respectivamente (Yue et al, 2021). Cerca d e 73% da chuva costuma alcançar o solo como precipitação interna.…”

Seasonal Partitioning of Rainfall in Second-Growth Evergreen Temperate Rainforests in Chiloé Island, Southern Chile

“…In the meantime, forest fragmentation progresses by logging, fire, and clearance, with dramatic effects on the structure and composition of temperate forests (Armesto et al, 2010;Echeverría et al, 2012). Such changes in vegetation impact hydrological processes, such as rainfall partitioning that may itself affect the hydrological cycle and climate at continental and local scales (Sadeghi et al, 2020;Van Stan and Friesen, 2020;Yue et al, 2021). Important changes occur in catchment-scale water balances, evapotranspiration, and rainfall interception and distribution (Crockford and Richardson, 2000;Sadeghi et al, 2020;Van Stan and Friesen, 2020;Yue et al, 2021).…”

“…In this context, precipitation partitioning by vegetation is a key process for water flow and storage in terrestrial vegetated ecosystems, since the interception of rainfall by plant canopies affects hydrologic processes, including related flows of materials and energy, and drives microclimate conditions, biodiversity, and ecosystem functions (Crockford and Richardson, 2000;Gutmann, 2020;Sadeghi et al, 2020;Van Stan and Friesen, 2020;Yue et al, 2021). Rainfall partitioning depends mainly on precipitation frequency and intensity, evaporation from the wet canopy and vegetation structure, but also from canopy gap sizes, air moisture, and water stored in the canopy at the beginning of each new rainfall event (Díaz et al, 2007;Gutmann, 2020;Van Stan and Friesen, 2020;Yue et al, 2021). Rainfall partitioning further depends on plant community structure characteristics, such as species composition, basal area, stem density, and leaf area and foliage type (Crockford and Richardson, 2000;Van Stan and Friesen, 2020;Yue et al, 2021).…”