Institut d'Ecologia Aquàtica, Facultat de Ciències, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain.
Centre d'Estudis Avançats de Blanes-CSIC, Accés Cala Sant Francesc 14, 17300, Blanes, Girona, Spain.
Sci Rep. 2019 Apr 11;9(1):5911. doi: 10.1038/s41598-019-41929-0.
Stochastic perturbations can trigger major ecosystem shifts. Marine systems have been severely affected in recent years by mass mortality events related to positive thermal anomalies. Although the immediate effects in the species demography affected by mortality events are well known, information on the mid- to long-term effects at the community level is much less documented. Here, we show how an extreme warming event replaces a structurally complex habitat, dominated by long-lived species, by a simplified habitat (lower species diversity and richness) dominated by turf-forming species. On the basis of a study involving the experimental manipulation of the presence of the gorgonian Paramuricea clavata, we observed that its presence mitigated the effects of warming by maintaining the original assemblage dominated by macroinvertebrates and delaying the proliferation and spread of the invasive alga Caulerpa cylindracea. However, due to the increase of sediment and turf-forming species after the mortality event we hypothesize a further degradation of the whole assemblage as both factors decrease the recruitment of P.clavata, decrease the survival of encrusting coralligenous-dwelling macroinvertebrates and facilitate the spreading of C. cylindracea.
随机干扰可能会引发重大生态系统变化。近年来，海洋系统受到了与正热异常有关的大规模死亡事件的严重影响。虽然与死亡率事件相关的物种种群的直接影响是众所周知的，但关于群落水平的中长期影响的信息记录要少得多。在这里，我们展示了极端变暖事件如何通过形成草坪的物种取代结构复杂、以长寿物种为主的栖息地（物种多样性和丰富度较低）。基于一项涉及对柳珊瑚 Paramuricea clavata 存在的实验性操纵的研究，我们观察到，由于它的存在减缓了变暖的影响，维持了以大型无脊椎动物为主的原始组合，并延迟了入侵藻类 Caulerpa cylindracea 的增殖和扩散。然而，由于死亡率事件后沉积物和形成草坪的物种增加，我们假设整个组合会进一步退化，因为这两个因素都会降低 P.clavata 的繁殖，降低固着珊瑚礁居住的大型无脊椎动物的存活率，并促进 C. cylindracea 的扩散。
