Spread of proliferative kidney disease in fish along stream networks: A spatial metacommunity framework
Spread of proliferative kidney disease in fish along stream networks: A spatial metacommunity framework
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DOI：
10.1111/fwb.12939
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发表时间：
2018-01-01
影响因子：
2.7
通讯作者：
Bertuzzo, Enrico
中科院分区：
文献类型：
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作者：
Carraro, Luca;Mari, Lorenzo;Bertuzzo, Enrico
1.增殖性肾脏病(PKD)是一种严重影响淡水鲑鱼种群的高死亡率病理。感染是由以淡水苔藓虫为主要宿主的内寄生粘虫四囊藻引起的。最近，PKD的发病率和严重性有所增加，这主要是由于气候变化导致的水温上升，导致许多河流系统的渔获量下降和局部灭绝。这里，基于最近提出的PKD传播的局部模型，开发了一个空间显式元社区框架来研究疾病在理想化河流网络中传播的空间效应。在当地社区规模上，该模型考虑了苔藓虫和鱼类种群的人口和流行病学动态。在网络尺度上，该模型通过寄生虫孢子的水文传输和鱼类的移动来耦合每个当地社区的动态。该模型还明确考虑了河网沿线生境特征和水文条件的异质性。通过对从最优航道网络派生的合成河网副本的模拟实验，研究了网络效应，生成树再现了真实河流的所有相互连接的拓扑和度量特征。即使鱼和苔藓虫的基本空间分布是同质的，网络连接也可能产生PKD流行的不同模式。流行率一般在下游地点较高：如果忽略鱼类的流动性，流行率的空间分布遵循上游集水区的分布；否则，流行率模式与出水口附近相关。由于水文孢子运输的快速动力学，PKD的下游入侵速度普遍较高。对于测定值，水温对流行异质性的影响较小。然而，气候变化可能会增加下游和上游的入侵速度。在上游或下游热点地区持续感染的条件下，无苔藓虫河段可发生PKD。这些结果进一步加深了我们对河流生态系统鱼类分布驱动因素的理解，并可能为开发干预和管理工具提供基础，特别是在面对气候变化的情况下。
1. Proliferative kidney disease (PKD) is a high-mortality pathology that critically affects freshwater salmonid populations. Infection is caused by the endoparasitic myxozoan Tetracapsuloides bryosalmonae, which exploits freshwater bryozoans as primary hosts. Incidence and severity of PKD have recently increased, largely owing to rising water temperatures linked to climate change, causing a decline in fish catches and local extinctions in many river systems.2. Here, building on a recently proposed local model of PKD transmission, a spatially explicit metacommunity framework is developed to study the spatial effects of the disease spread in idealised stream networks. At the local community scale, the model accounts for demographic and epidemiological dynamics of bryozoan and fish populations. At the network scale, the model couples the dynamics of each local community through hydrological transport of parasite spores and fish movement. The model also explicitly accounts for heterogeneity in habitat characteristics and hydrological conditions along a river network.3. Network effects are investigated by running simulation experiments on synthetic river network replicas derived from Optimal Channel Networks, spanning trees known to reproduce all the mutually connected topological and metric features of real rivers.4. Network connectivity can produce heterogeneous patterns of PKD prevalence even when the underlying spatial distributions of fish and bryozoans are homogeneous. Prevalence is generally higher at the downstream sites: if fish mobility is neglected, the spatial distribution of prevalence follows that of the upstream drainage area; otherwise, prevalence patterns are correlated with the proximity to the outlet. Downstream invasion speed of PKD is generally high, due to the fast dynamics of hydrological spore transport. For the tested values, effects of water temperature on prevalence heterogeneity are minor. However, climate change may increase invasion speed in both downstream and upstream directions. PKD can establish in bryozoanfree river reaches, on the condition that the infection be sustained by upstream or downstream hot-spots. These results further our understanding of the drivers of fish distribution in riverine ecosystems and may provide the basis for the development of intervention and management tools, especially facing climate change.