Biodiversity declines due to abandonment and intensification of agricultural lands: patterns and mechanisms
Biodiversity declines due to abandonment and intensification of agricultural lands: patterns and mechanisms
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DOI：
10.1890/13-2170.1
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发表时间：
2014-11
影响因子：
6.1
通讯作者：
K. Uchida;A. Ushimaru
中科院分区：
文献类型：
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作者：
K. Uchida;A. Ushimaru
世界各地的农业地区都对由于土地利用废弃和集约化导致的植物和草食性昆虫的减少进行了研究。我们测试了四种假设，它们是互补的而不是相互排斥的，以了解由于废弃和集约化而导致生物多样性下降的机制。这些预测生物多样性下降是由资源多样性下降、干扰机制变化、周围景观转变和生物量生产减少引起的。我们比较了半自然草原三种土地利用类型（废弃梯田、传统梯田和集约化梯田）的植物丰富度以及蝴蝶和直翅类丰富度和多样性。然后，我们研究了资源（植物）丰富度、干扰频率（割草）和周围景观的变化对蝴蝶和直翅类多样性的影响，以了解土地撂荒和集约化后驱动衰退的机制。废弃和集约化草原的植物和食草动物丰富度和多样性显着低于传统草原。在研究的两年中，这种趋势在整个季节都是一致的。割草频率和周围景观的变化解释了土地废弃和集约化导致植物丰富度下降的原因。草食性昆虫的减少可以用植物丰富度下降和割草频率的变化来解释，但不能用景观变化来解释。中等割草频率（大约每年两次）可以最大限度地提高植物和食草动物的丰富度，这是传统梯田的典型做法。这是第一份证明中间干扰假说很好地解释了农业生态系统生物多样性下降的报告。食草动物功能群对植物丰富度、割草频率和周围景观的丰富度和多样性反应通常与预测不一致。我们发现传统梯田中丰度较低的蝴蝶和直翅类物种在废弃和/或密集梯田中消失的显着趋势。这可能表明，随着干扰频率变化后植物丰富度下降，大多数草食性物种的个体数量在生活史特征方面随机减少。这项研究表明，草食性昆虫的减少可以由多种因素来解释，并为农业用地废弃和集约化利用中生物多样性的下降提供了统一的解释，而这两种情况通常是分开研究的。
Declines in plants and herbivorous insects due to land use abandonment and intensification have been studied in agricultural areas worldwide. We tested four hypotheses, which were complementary rather than mutually exclusive, to understand the mechanisms driving biodiversity declines due to abandonment and intensification. These predict that biodiversity decline is caused by a decline in resource diversity, changes in disturbance regime, surrounding landscape conversion, and a decrease in biomass production. We compared plant richness and butterfly and orthopteran richness and diversity among three land use types in seminatural grasslands: abandoned, traditional, and intensified terraces. Then, we examined effects of changes in resource (plant) richness, frequency of disturbance (mowing), and surrounding landscapes on butterfly and orthopteran diversity to understand the mechanisms driving decline after land abandonment and intensification. Plant and herbivore richness and diversity were significantly lower in abandoned and intensified grasslands than in traditional grasslands. This trend was consistent throughout the seasons in both years of the study. Changes in mowing frequency and surrounding landscape explained plant richness declines as a consequence of land abandonment and intensification. Declines in herbivorous insects were explained by plant richness declines and changes in mowing frequency, but not by landscape changes. Plant and herbivore richness were maximized at an intermediate mowing frequency (approximately twice per year), which is typical practice on traditional terraces. This is the first report demonstrating that the intermediate disturbance hypothesis explained well the biodiversity declines in agricultural ecosystems. The richness and diversity responses of herbivore functional groups to plant richness, mowing frequency, and surrounding landscapes were generally inconsistent with predictions. We found significant trends in which butterfly and orthopteran species with low abundance in traditional terraces were lost in abandoned and/or intensive terraces. This may suggest that the number of individuals of most herbivorous species decreased randomly with respect to life-history traits following a decline in plant richness after changes in disturbance frequency. This study demonstrates that declines in herbivorous insects can be explained by multiple factors, and provides a unified explanation for biodiversity declines in both abandoned and intensified use of agricultural lands, which have often been studied separately.