Species turnover of monkey beetles (Scarabaeidae: Hopliini) along environmental and disturbance gradients in the Namaqualand region of the succulent Karoo, South Africa
Species turnover of monkey beetles (Scarabaeidae: Hopliini) along environmental and disturbance gradients in the Namaqualand region of the succulent Karoo, South Africa
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DOI：
10.1023/a:1014520226989
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发表时间：
2002-02-01
影响因子：
3.4
通讯作者：
Cowling, RM
中科院分区：
文献类型：
--
作者：
Colville, J;Picker, MD;Cowling, RM
在南非多汁的卡鲁干旱、冬季降雨的纳马夸兰地区的三个地点，研究了猴甲虫（金龟子科：Hopliini）沿着干扰和环境梯度的物种更替。在每个地点，选择了两个具有相似植被和土壤但具有对比管理（放牧）历史的研究地块，受干扰的地点有较少的多年生灌木，通常有更多的一年生植物和裸地。使用彩色盘式陷阱收集的甲虫在受干扰的地点显示出持续较高的丰度。 Lepithrix、Denticnema 和 Heterochelus 在受干扰的地块中数量较多，而 Peritrichia 的数量在受干扰的地区较低。在未受干扰的地点，物种丰富度和多样性的测量值始终较高。每个地点都出现了独特的猴甲虫和植物组合。沿着降雨梯度，猴甲虫和植物都记录到了较高的成分更新（β多样性）；站点间 beta 多样性值范围为 0.7 至 0.8（最大值为 1.0）。沿着环境梯度，受干扰地点之间的甲虫物种更替率高于相应的未受干扰地点。猴甲虫物种的高周转率可能与植物物种的高周转率有关，这是卡鲁多肉景观的一个显着特征。猴甲虫是纳马夸兰过度放牧干扰的有用指标，因为它们的传粉者行会显然因过度放牧而受到干扰。在受干扰的地区，观察到从多年生植物和球茎传粉者协会转向青睐一年生杂草植物的情况。讨论了由于扰动对猴甲虫群落的影响而对生态系统过程造成的后果，以及猴甲虫作为扰动指标的作用，以及扰动对猴甲虫授粉行会的影响。
Species turnover of monkey beetle (Scarabaeidae: Hopliini) assemblages along disturbance and environmental gradients was examined at three sites within the arid, winter rainfall Namaqualand region of the succulent Karoo, South Africa. At each site two study plots with comparable vegetation and soils but contrasting management (grazing) histories were chosen, the disturbed sites having fewer perennial shrubs and generally more annuals and bare ground. Beetles collected using coloured pan-traps showed a consistently higher abundance in disturbed sites. Lepithrix, Denticnema and Heterochelus had higher numbers in disturbed plots, while Peritrichia numbers were lower in disturbed areas. Measures of species richness and diversity were consistently higher in the undisturbed sites. Distinctive assemblages of monkey beetles and plants occurred at each site. A high compositional turnover (beta diversity) was recorded for both monkey beetles and plants along a rainfall gradient; between-site beta diversity values ranged from 0.7 to 0.8 (out of a maximum of 1.0). Species turnover of beetles was higher between the disturbed sites along the environmental gradient than the corresponding undisturbed sites. The high monkey beetle species turnover is probably linked to the high plant species turnover, a distinctive feature of succulent Karoo landscapes. Monkey beetles are useful indicators of overgrazing disturbance in Namaqualand, as their pollinator guilds are apparently disrupted by overgrazing. A shift away from perennial and bulb pollinator guilds towards those favouring weedy annuals was observed in disturbed areas. The consequences to ecosystem processes due to the effects of disturbance on monkey beetle communities and the role of monkey beetles as indicators of disturbance is discussed, as well as the implications of disturbance on monkey beetle pollination guilds.