Department of Geography & Earth Sciences, Center for Applied GIScience, University of North Carolina, Charlotte, NC 28223, USA.
Ecol Lett. 2011 Nov;14(11):1108-16. doi: 10.1111/j.1461-0248.2011.01679.x. Epub 2011 Sep 2.
Empirical evidence suggests that biodiversity loss can increase disease transmission, yet our understanding of the 'diversity-disease hypothesis' for generalist pathogens in natural ecosystems is limited. We used a landscape epidemiological approach to examine two scenarios regarding diversity effects on the emerging plant pathogen Phytophthora ramorum across a broad, heterogeneous ecoregion: (1) an amplification effect exists where disease risk is greater in areas with higher plant diversity due to the pathogen's wide host range, or (2) a dilution effect where risk is reduced with increasing diversity due to lower competency of alternative hosts. We found evidence for pathogen dilution, whereby disease risk was lower in sites with higher species diversity, after accounting for potentially confounding effects of host density and landscape heterogeneity. Our results suggest that although nearly all plants in the ecosystem are hosts, alternative hosts may dilute disease transmission by competent hosts, thereby buffering forest health from infectious disease.
实证证据表明，生物多样性的丧失会增加疾病的传播，但我们对自然生态系统中广义病原体的“多样性-疾病假说”的理解是有限的。我们使用景观流行病学方法，针对广谱、异质生态区中新兴植物病原体松材线虫的多样性效应，检验了两种情况：（1） 放大效应，由于病原体广泛的宿主范围，植物多样性较高的地区疾病风险更大；（2） 稀释效应，由于替代宿主的竞争力下降，多样性增加会降低风险。在考虑了宿主密度和景观异质性的潜在混杂效应后，我们发现了病原体稀释的证据，即在物种多样性较高的地点，疾病风险较低。我们的研究结果表明，尽管生态系统中的几乎所有植物都是宿主，但替代宿主可能会通过有竞争力的宿主稀释疾病的传播，从而保护森林健康免受传染病的侵害。
