Garcia Maria O, Smith Jane E, Luoma Daniel L, Jones Melanie D
Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA.
Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA.
Mycorrhiza. 2016 May;26(4):275-86. doi: 10.1007/s00572-015-0668-x. Epub 2015 Nov 7.
Forest ecosystems of the Pacific Northwest of the USA are changing as a result of climate change. Specifically, rise of global temperatures, decline of winter precipitation, earlier loss of snowpack, and increased summer drought are altering the range of Pinus contorta. Simultaneously, flux in environmental conditions within the historic P. contorta range may facilitate the encroachment of P. ponderosa into P. contorta territory. Furthermore, successful pine species migration may be constrained by the distribution or co-migration of ectomycorrhizal fungi (EMF). Knowledge of the linkages among soil fungal diversity, community structure, and environmental factors is critical to understanding the organization and stability of pine ecosystems. The objectives of this study were to establish a foundational knowledge of the EMF communities of P. ponderosa and P. contorta in the Deschutes National Forest, OR, USA, and to examine soil characteristics associated with community composition. We examined EMF root tips of P. ponderosa and P. contorta in soil cores and conducted soil chemistry analysis for P. ponderosa cores. Results indicate that Cenococcum geophilum, Rhizopogon salebrosus, and Inocybe flocculosa were dominant in both P. contorta and P. ponderosa soil cores. Rhizopogon spp. were ubiquitous in P. ponderosa cores. There was no significant difference in the species composition of EMF communities of P. ponderosa and P. contorta. Ordination analysis of P. ponderosa soils suggested that soil pH, plant-available phosphorus (Bray), total phosphorus (P), carbon (C), mineralizable nitrogen (N), ammonium (NH4), and nitrate (NO3) are driving EMF community composition in P. ponderosa stands. We found a significant linear relationship between EMF species richness and mineralizable N. In conclusion, P. ponderosa and P. contorta, within the Deschutes National Forest, share the same dominant EMF species, which implies that P. ponderosa may be able to successfully establish within the historic P. contorta range and dominant EMF assemblages may be conserved.
由于气候变化，美国太平洋西北部的森林生态系统正在发生变化。具体而言，全球气温上升、冬季降水量减少、积雪提前消融以及夏季干旱加剧正在改变扭叶松的分布范围。同时，在扭叶松的历史分布范围内，环境条件的变化可能会促使西黄松侵入扭叶松的领地。此外，成功的松树物种迁移可能会受到外生菌根真菌（EMF）分布或共同迁移的限制。了解土壤真菌多样性、群落结构和环境因素之间的联系对于理解松树生态系统的组织和稳定性至关重要。本研究的目的是在美国俄勒冈州德舒特国家森林中建立西黄松和扭叶松EMF群落的基础知识，并研究与群落组成相关的土壤特征。我们检查了土壤芯样中西黄松和扭叶松的EMF根尖，并对西黄松芯样进行了土壤化学分析。结果表明，土生空团菌、粗糙须腹菌和絮状丝盖伞在扭叶松和西黄松的土壤芯样中均占主导地位。须腹菌属在西黄松芯样中普遍存在。西黄松和扭叶松EMF群落的物种组成没有显著差异。对西黄松土壤的排序分析表明，土壤pH值、植物有效磷（Bray法）、总磷（P）、碳（C）、可矿化氮（N）、铵（NH4）和硝酸盐（NO3）驱动着西黄松林中EMF群落的组成。我们发现EMF物种丰富度与可矿化氮之间存在显著的线性关系。总之，在德舒特国家森林中，西黄松和扭叶松共享相同的优势EMF物种，这意味着西黄松可能能够在扭叶松的历史分布范围内成功定植，并且优势EMF组合可能得到保留。
