Are all ant mosaics caused by competition?
Are all ant mosaics caused by competition?
复制标题
蚂蚁马赛克都是竞争造成的吗？
作者：
C. Ribas;J. Schoereder
在本文中，我们测试的假设，蚂蚁马赛克产生和维护的随机过程，对一般的想法，确定性的过程，如竞争，是这些社区的结构的主要力量。我们分析了14个已发表的蚂蚁马赛克，描述了农作物和天然林，转换他们的数据存在/不存在矩阵。使用生成空模型的软件，将这些矩阵提交给种属共现分析。观察到的物种共生指数，然后统计比较的空矩阵，以测试是否有证据的生物过程结构的蚂蚁群落。从分析的14个马赛克，七个少，一个有更多的共同出现比预期的机会。在六个马赛克，物种共现的随机矩阵的频率分布的95%的限制内。即使观察蚂蚁的空间分布，连同物种对之间的关联指数，通常被解释为负相互作用的结果，我们的研究结果表明，只有50%的研究马赛克有证据表明这种解释。此外，除了竞争假说外，还有其他假说可以解释偶然共现比预期少的结果。蚂蚁物种与资源和条件的关联也可以解释观察到的模式，尽管这些假设很少被利用。总之，竞争可能是一个重要的过程时，研究蚂蚁社区的组装规则，虽然它肯定不是唯一的过程。其他生物过程和随机事件的重要性必须考虑到解释物种分布模式。
In this paper we tested the hypothesis that ant mosaics are generated and maintained by stochastic processes, against the general idea that deterministic processes, such as competition, are the main forces that structure these communities. We analysed 14 published ant mosaics, described for crops and natural forests, transforming their data in presence/absence matrices. These matrices were submitted to species co-occurrence analysis, using software that generates null models. The observed species co-occurrence index was then statistically compared to the null matrices, to test whether there is evidence for biological processes structuring the ant communities. From the 14 mosaics analysed, seven had less and one had more co-occurrence than expected by chance. In six mosaics, species co-occurrence was within the 95% limits of frequency distribution of randomized matrices. Even though the observation of ant spatial distribution, together with association indices between species pairs, have usually been interpreted as a result of negative interactions, our results show that in only 50% of the studied mosaics there is evidence for this explanation. Furthermore, there are alternative hypotheses to explain the result of less co-occurrence than expected by chance, besides the competition hypothesis. Association of ant species with resources and conditions may also explain the observed pattern, although these hypotheses are rarely exploited. In conclusion, competition may be an important process when studying assembly rules in ant communities, although it is certainly not the only process involved. The importance of other biological processes and of stochastic events has to be taken into account to explain the species distribution patterns.