Oke Tobi A, Hager Heather A
Department of Integrative Biology, University of Guelph, Guelph, ON, Canada.
PLoS One. 2017 Apr 20;12(4):e0175978. doi: 10.1371/journal.pone.0175978. eCollection 2017.
The fate of Northern peatlands under climate change is important because of their contribution to global carbon (C) storage. Peatlands are maintained via greater plant productivity (especially of Sphagnum species) than decomposition, and the processes involved are strongly mediated by climate. Although some studies predict that warming will relax constraints on decomposition, leading to decreased C sequestration, others predict increases in productivity and thus increases in C sequestration. We explored the lack of congruence between these predictions using single-species and integrated species distribution models as proxies for understanding the environmental correlates of North American Sphagnum peatland occurrence and how projected changes to the environment might influence these peatlands under climate change. Using Maximum entropy and BIOMOD modelling platforms, we generated single and integrated species distribution models for four common Sphagnum species in North America under current climate and a 2050 climate scenario projected by three general circulation models. We evaluated the environmental correlates of the models and explored the disparities in niche breadth, niche overlap, and climate suitability among current and future models. The models consistently show that Sphagnum peatland distribution is influenced by the balance between soil moisture deficit and temperature of the driest quarter-year. The models identify the east and west coasts of North America as the core climate space for Sphagnum peatland distribution. The models show that, at least in the immediate future, the area of suitable climate for Sphagnum peatland could expand. This result suggests that projected warming would be balanced effectively by the anticipated increase in precipitation, which would increase Sphagnum productivity.
由于北方泥炭地对全球碳储存有贡献，其在气候变化下的命运至关重要。泥炭地通过比分解作用更高的植物生产力（特别是泥炭藓物种）得以维持，且相关过程受气候强烈影响。尽管一些研究预测变暖将缓解对分解的限制，导致碳固存减少，但其他研究预测生产力会增加，从而碳固存也会增加。我们使用单物种和综合物种分布模型作为代理，探讨这些预测之间缺乏一致性的问题，以了解北美泥炭藓泥炭地出现的环境相关因素，以及预计的环境变化在气候变化下可能如何影响这些泥炭地。利用最大熵和BIOMOD建模平台，我们针对北美四种常见泥炭藓物种，在当前气候以及由三个大气环流模型预测的2050年气候情景下，生成了单物种和综合物种分布模型。我们评估了模型的环境相关因素，并探讨了当前和未来模型在生态位宽度、生态位重叠和气候适宜性方面的差异。模型一致表明，泥炭藓泥炭地的分布受土壤水分亏缺与最干旱季度温度之间平衡的影响。模型确定北美东海岸和西海岸为泥炭藓泥炭地分布的核心气候空间。模型显示，至少在不久的将来，适合泥炭藓泥炭地的气候区域可能会扩大。这一结果表明，预计的变暖将被预期的降水增加有效平衡，这将提高泥炭藓的生产力。
