Polar regions are currently warming at a rate above the global average. One issue of concern is the consequences on biodiversity in relation to the Northward latitudinal shift in distribution of temperate species. In the present study, lasting almost two years, we examined two phenological traits, i.e. the shell growth and behavioural rhythm of a recently re-established species in the high Arctic, the blue mussel Mytilus sp. We compared this with a native species, the Islandic scallop Chlamys islandica. We show marked differences in the examined traits between the two species. In Mytilus sp., a clear annual pattern of shell growth strongly correlated to the valve behaviour rhythmicity, whereas C. islandica exhibited a shell growth pattern with a total absence of annual rhythmicity of behaviour. The shell growth was highly correlated to the photoperiod for the mussels but weaker for the scallops. The water temperature cycle was a very weak parameter to anticipate the phenology traits of both species. This study shows that the new resident in the high Arctic, Mytilus sp., is a highly adaptive species, and therefore a promising bioindicator to study the consequences of biodiversity changes due to global warming.

极地地区目前正在以高于全球平均水平的速度变暖。一个令人关注的问题是与温带物种分布的北纬纬度变化有关的生物多样性后果。在本研究中，持续了将近两年，我们研究了两个物候特征，即北极高地蓝贻贝Mytilus sp。中最近重新建立的物种的壳生长和行为节律。我们将其与本地物种，即扇贝Chlamys islandica进行了比较。我们在两种物种的性状上显示出显着差异。在Mytilus sp。中，壳的明显年度生长模式与瓣膜行为的节律性密切相关，而C. islandica表现出壳的生长模式，完全没有年度行为的节奏。贻贝的壳生长与光周期高度相关，而扇贝的壳生长较弱。水温循环是一个非常弱的参数，无法预测两个物种的物候特征。这项研究表明，北极新居者Mytilus sp。是高度适应性物种，因此是研究全球变暖导致生物多样性变化后果的有前途的生物指示剂。