Modeling the potential distribution of Epiphyllum phyllanthus (L.) Haw. under future climate scenarios in the Caatinga biome

Abstract The climate change projections for the Caatinga biome this century are for an increase in temperature and reduction in rainfall, leading to aridization and plant cover dominated by Cactaceae. The objective of this study was to model the potential distribution of Epiphyllum phyllanthus (L.) Haw., a cactus that is native to the Caatinga biome, considering two possible future climate scenarios, to assess this species’ spatio-temporal response to these climate change, and thus to evaluate the need or not for conservation measures. For this purpose, we obtained biogeographic information on the target species from biodiversity databases, choosing nine environmental variables and applying the MaxEnt algorithm. We considered the time intervals 2041-2060 and 2061-2080, centered on 2050 and 2070, respectively, and the greenhouse gas scenarios RCP4.5 and 8.5. For all the scenarios considered, the models generated for 2050 and 2070 projected drastic contraction (greater than 80%) for the areas of potential occurrence of the species in relation to the present potential. The remaining areas were found to be concentrated in the northern portion of the biome, specifically in the northern part of the state of Ceará, which has particular characteristics.

摘要 本研究针对本世纪卡廷加生物群区（Caatinga biome）的气候变化预估展开分析，预估结果显示该区域将呈现气温升高、降水减少的趋势，进而引发干旱化，最终形成以仙人掌科（Cactaceae）为主的植被覆盖。本研究的目标为针对原产于卡廷加生物群区的仙人掌物种（Epiphyllum phyllanthus (L.) Haw.），基于两种未来气候情景构建其潜在分布模型，以评估该物种对气候变化的时空响应，进而判断是否需要采取保护措施。为此，研究团队从生物多样性数据库中获取目标物种的生物地理信息，筛选出9项环境变量，并应用最大熵模型（MaxEnt）开展分析。研究选取两个未来时段：2041-2060年（以2050年为中心）与2061-2080年（以2070年为中心），并采用温室气体情景典型浓度路径（RCP）4.5与8.5。所有模拟情景的结果均表明，相较于当前潜在分布区，2050年与2070年该物种的潜在发生区将出现超过80%的剧烈缩减，剩余的潜在分布区将集中于该生物群区的北部区域，具体为塞阿拉州北部，该区域具备独特的环境特征。