Macquarie Island soil collection site details for 2009/10 season - Azorella dieback project, Macquarie Island

This data contains the spatial information associated with the sites from which the soil samples were collected. It also contains the initial weights for each soil sample. Soil samples were collected as part of the PhD thesis of Jared Abdul-Rahman, Spatiotemporal characteristics and causes of damage to Azorella macquariensis cushions. Azorella macquariensis is a perennial cushion-forming herb that is endemic to Macquarie Island. During the 2008/09 austral summer, widespread dieback in A. macquariensis was observed, and is regarded by many to be a new phenomenon. The dieback is perceived to have spread across the entire island, affecting up to ~0 % of cushions in some areas. As a result of this perception the species has been listed as critically endangered under the Environment Protection and Biodiversity Conservation (EPBC) Act 1999. Although there have been speculations about potential contributing factors, a definite cause has not been determined. The spatiotemporal characteristics of three dominant damage types affecting the cushion plant were investigated to help determine the cause/s of the putative increasing damage. In the austral summer of 2009/10, data were collected in the course of four studies: a cushion profile study; mapping of the spatial variation of cushion health; monitoring of temporal variation in cushion health; and a study relating soils to health. There was no significant relationship between overall cushion health and environmental variables apart from health decreasing with increasing exposure to strong winds. Type 1 damage was found to be more concentrated on the windward sectors of cushions, was significantly related to cushion exposure, substrate and vegetation community and did not display any major temporal variability. Type 2 damage was found to be more concentrated on the leeward sectors of cushions, was significantly related to cushion exposure, substrate and vegetation community and also did not display any major temporal variability. Type 3 damage was not significantly related to any particular sectors of cushions, nor to the environmental variables with the exception of cushion substrate, and expanded rapidly during the warm season. This suggested that the spatially restricted Type 3 damage might be responsible for the perception of increased dieback. Its cause is uncertain, although many of the symptoms are similar to those of a pathogen. Future monitoring should concentrate on this type of damage.本数据集包含土壤样本采集点位的相关空间信息，以及每份土壤样本的初始重量。 这些土壤样本采集自贾里德·阿卜杜勒-拉赫曼（Jared Abdul-Rahman）的博士学位论文《Azorella macquariensis垫状植株受损的时空特征与成因》。 Azorella macquariensis是仅分布于麦夸里岛的多年生垫状草本植物。2008/2009年南半球夏季，该物种出现大范围枯衰现象，这被众多学者视为一种新型现象。此次枯衰据称已蔓延至全岛，部分区域的垫状植株受损比例最高约为0%。基于这一情况，该物种被依据1999年《环境保护与生物多样性保育（EPBC）法案》列为极危物种。 尽管学界已针对潜在致病诱因提出诸多推测，但尚未确定明确成因。本次研究针对该垫状植物的三种主要受损类型的时空特征展开调查，以期明确该疑似不断加剧的受损现象的成因。2009/2010年南半球夏季，四项研究中采集了相关数据：垫状植株剖面研究、垫状健康状况空间变异制图、垫状健康状况时间动态监测，以及土壤与健康状况关联研究。 分析结果显示，除整体健康状况随强风暴露程度升高而下降外，垫状植株的整体健康状况与其余环境变量均无显著关联。1型受损更集中于垫状植株的迎风侧区域，与植株暴露程度、基质及植被群落显著相关，且未表现出显著的时间动态变化。2型受损更集中于垫状植株的背风侧区域，同样与植株暴露程度、基质及植被群落显著相关，亦未表现出显著的时间动态变化。3型受损与垫状植株的特定区域无显著关联，除垫状基质外与其余环境变量均无显著相关性，但在暖季扩张迅速。这表明空间分布受限的3型受损可能是此次枯衰现象加剧认知的成因，尽管其症状与病原体引发的病害高度相似，但该类型受损的具体成因仍不明确。未来的监测工作应重点关注此类受损类型。