Foliar disease incidence in a tropical seedling community is density dependent and varies along a regional precipitation gradient
Foliar disease incidence in a tropical seedling community is density dependent and varies along a regional precipitation gradient
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DOI：
10.1111/1365-2745.14259
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发表时间：
2024-01
影响因子：
5.5
通讯作者：
V. Milici;L. Comita;R. Bagchi
中科院分区：
文献类型：
--
作者：
V. Milici;L. Comita;R. Bagchi
许多研究将真菌和卵菌植物病原体确定为能够影响植物物种组成和促进植物群落多样性的天敌。然而，很少有人知道如何植物病原体相互作用沿着区域非生物梯度或树种的特点，这限制了我们的了解，在树木物种丰富度的变化的原因。我们调查了10，756苗从272树种的疾病症状沿着平均年降水梯度在巴拿马中部的热带潮湿森林3个月的雨季初（6月至8月）和2个月的旱季（3月至4月）。超过99%的观察到的疾病症状引起的坏死营养叶病原体，而不到1%的症状归因于土传病原体。叶病发病率呈负相关的平均年降水量，这可能是由于干旱的森林物种之间的疾病易感性更大的模式。叶片病害的发病率增加，同种幼苗密度，但没有响应同种成人的接近。虽然叶病发病率随着年平均降水量的增加而降低，但同种密度或距离依赖性的强度与降水梯度无关。常见树种和由非飞行哺乳动物传播的物种的幼苗具有较高的叶面病原体发病风险。常见物种中疾病的增加可能有助于降低它们的优势。合成.叶片病原体发病率随同种幼苗密度、物种丰富度和传播机制的增加而增加，表明叶片病害发病率是非随机的，可能有助于调节热带植物群落和物种共存。此外，叶部病害发病率，传播机制和降水之间的关系表明，植物病原体的相互作用可能会随着气候变化和传播者群落的破坏而改变。
Many studies identify fungal and oomycete phytopathogens as natural enemies capable of influencing plant species composition and promoting diversity in plant communities. However, little is known about how plant‐pathogen interactions vary along regional abiotic gradients or with tree species characteristics, which limits our understanding of the causes of variation in tree species richness. We surveyed 10,756 seedlings from 272 tree species for disease symptoms along a mean annual precipitation gradient in the tropical wet forests of Central Panama for 3 months in the early wet season (June–August) and 2 months in the following dry season (March–April). Over 99% of observed disease symptoms were caused by necrotrophic foliar pathogens, while less than 1% of symptoms were attributed to soilborne pathogens. Foliar disease incidence was inversely related to mean annual precipitation, a pattern which may be due to greater disease susceptibility among dry forest species. Foliar disease incidence increased with conspecific seedling density but did not respond to the proximity of conspecific adults. Although foliar disease incidence decreased as mean annual precipitation increased, the strength of conspecific density‐ or distance‐dependence was independent of the precipitation gradient. Seedlings of common tree species and species dispersed by non‐flying mammals had a higher risk of foliar pathogen incidence. Increased disease in common species may help reduce their dominance. Synthesis. The increases in foliar pathogen incidence with conspecific seedling density, species abundance, and dispersal mechanism indicate that foliar disease incidence is non‐random and may contribute to the regulation of tropical plant communities and species coexistence. Furthermore, the relationships between foliar disease incidence, dispersal mechanism and precipitation suggest plant‐pathogen interactions could shift as a response to climate change and disruption of the disperser community.