Bozimowski Alexandra A, Murry Brent A, Uzarski Donald G
Institute for Great Lakes Research Central Michigan University Mount Pleasant Michigan USA.
Division of Forestry and Natural Resources, Davis College West Virginia University Morgantown West Virginia USA.
Ecol Evol. 2024 Dec 2;14(12):e70622. doi: 10.1002/ece3.70622. eCollection 2024 Dec.
In niche-based community assembly theory, it is presumed that communities in habitats with high natural disturbance regimes are less likely to be structured by competitive mechanisms. Laurentian Great Lakes (hereafter Great Lakes) coastal wetlands can experience drastic diel fluctuations in dissolved oxygen levels, severe wave action, ice scour, and near complete freezing during the winter such that conditions are inhospitable for most organisms. The high natural disturbance levels are thought to cause high interannual turnover for aquatic macroinvertebrate communities and support the hypothesis that these communities are less likely to experience less competitive interactions and negative co-occurrence structure. We hypothesize that non-random co-occurrence patterns will be rare in Great Lake coastal wetlands and non-competitive processes (e.g., through shared or differential microhabitat affinities, pollution tolerances, or biotic homogenization) will be more common than competitively driven negative co-occurrence patterns. Null model analysis was performed on 134 macroinvertebrate communities sampled from across the Great Lakes basin from 2000 to 2013. To disentangle the effects of alternative structuring mechanisms (i.e., shared/differential habitat affinities, shared/differential pollution tolerance, and biological homogenization/competitive exclusion), communities were parsed based on the year sampled, the vegetation type from which community samples were collected, and lastly species' functional feeding group assignment or taxonomic group. As expected, very few communities were non-randomly structured; however, all of those that were non-random exhibited showed more negative co-occurrences than by chance. Upon further investigation, these communities consisted of species that are known to overwinter in wetlands, and therefore, avoid having to recolonize after each spring thaw. With expected changes in habitat conditions due to climate change, we propose that null model analyses can be used as an early warning system for community change.
在基于生态位的群落构建理论中，假定在自然干扰程度高的栖息地中，群落不太可能由竞争机制构建而成。 Laurentian五大湖（以下简称五大湖）沿岸湿地的溶解氧水平可能会出现剧烈的昼夜波动，遭受严重的波浪作用、冰蚀，并且在冬季几乎完全冻结，以至于大多数生物难以生存。人们认为，高自然干扰水平会导致水生大型无脊椎动物群落的年际更替率很高，并支持这样一种假说，即这些群落不太可能经历较少的竞争相互作用和负共存结构。我们假设，在五大湖沿岸湿地中，非随机共存模式将很少见，并且非竞争过程（例如，通过共享或不同的微生境亲和力、污染耐受性或生物同质化）将比竞争驱动的负共存模式更为常见。对2000年至2013年从五大湖流域采集的134个大型无脊椎动物群落进行了空模型分析。为了厘清替代构建机制（即共享/不同的栖息地亲和力、共享/不同的污染耐受性以及生物同质化/竞争排斥）的影响，根据采样年份、采集群落样本的植被类型，最后是物种的功能摄食组分配或分类组对群落进行了剖析。正如预期的那样，很少有群落呈非随机结构；然而，所有非随机结构的群落显示出的负共存情况都比偶然情况更多。经进一步调查，这些群落由已知在湿地越冬的物种组成，因此避免了每年春季解冻后必须重新定殖的情况。鉴于气候变化导致栖息地条件的预期变化，我们建议空模型分析可作为群落变化的早期预警系统。
