A decision framework to attribute atmospheric nitrogen deposition as a threat to or cause of unfavourable habitat condition on protected sites

This report describes the development of a decision framework to provide a means of attributing nitrogen deposition as a threat to, or cause of, unfavourable habitat condition on protected sites.

The UKâs semi-natural habitats exceed their atmospheric nitrogen (N) deposition critical load ranges across much of their area, and survey data suggests there are adverse impacts of this excess N deposition. However, information from Common Standards Monitoring (CSM) of protected sites does not appear to identify N deposition as a potential cause of unfavourable condition at many sites. A decision framework was developed to provide a means of attributing N deposition as a threat to, or cause of, unfavourable habitat condition on protected sites. The framework provides a practical methodology for assessing the impacts of N deposition on protected sites in an objective way, which was previously lacking. It is based on a sound conceptual approach, and is both robust and flexible enough to cope with additional information.

The framework is described in the main report, whilst the detailed methodology is included in the supporting annexes.

* Annex 1: Strength of âtheoretical/nationalâ evidence (Work Package 1 report) â this describes in detail the scoring of national/theoretical evidence to derive an Exceedance Score.
* Annex 2: Strength of site-based evidence (Work Package 2 report) â this describes in detail the site-based evidence used to derive a score for strength of site-based evidence (Factor 2)
* Annex 3: Matrix design, testing and recommendations (Work Package 3 report) â this describes the version of the matrix as recommended by the contractors, provides recommendations for future work (the key recommendations from this are summarised in this main report), and briefly describes the testing undertaken as part of Work Package 3.

The accompanying zipped folder includes:
* Factor 1 spreadsheet (Exceedance Score) â this spreadsheet incorporates the elements of WP1 which generate the exceedance score for each CSM habitat (and sub-habitat) based on a user-defined deposition; guidance for utilising the spreadsheet is given in Annex 1.
* Factor 2 spreadsheets (N indicators) â these spreadsheets display the results of a review of all targets for each CSM habitat and the identification of strong and weak N indicators; guidance for the spreadsheets is given in Annex 2.
* Final assessment matrix â this Word Document provides a copy of the final assessment matrix.

本报告详述了一项决策框架的开发过程，旨在为确定氮沉降对保护地不利栖息地状况构成威胁或成为其成因提供一种方法。英国半自然栖息地的大气氮（N）沉降量已超过其大部分区域的临界负荷范围，且调查数据表明，这种超额氮沉降存在不良影响。然而，来自保护地通用标准监测（CSM）的信息似乎并未将氮沉降视为许多地点不利状况的潜在成因。为此，一项决策框架得以开发，旨在为确定氮沉降对保护地不利栖息地状况构成威胁或成为其成因提供一种方法。该框架提供了一种客观评估氮沉降对保护地影响的方法，该方法之前尚未存在。该框架基于严谨的概念性方法，既稳健又灵活，足以应对额外信息的补充。框架的描述包含在主要报告中，而详细的评估方法则包含在辅助附件中。

* 附件1：'理论/国家'证据的强度（工作包1报告）——该附件详细描述了国家/理论证据的评分过程，以推导出超额得分。
* 附件2：基于现场的证据强度（工作包2报告）——该附件详细描述了用于推导基于现场证据强度得分的证据（因素2）。
* 附件3：矩阵设计、测试和推荐（工作包3报告）——该附件描述了承包商推荐的矩阵版本，提供了未来工作的建议（本主要报告总结了关键建议），并简要描述了工作包3进行的测试。

随附的压缩文件夹包含以下内容：
* 因素1电子表格（超额得分）——该电子表格整合了工作包1的要素，根据用户定义的沉降量生成每个CSM栖息地（及其亚栖息地）的超额得分；关于如何使用该电子表格的指南包含在附件1中。
* 因素2电子表格（氮指标）——这些电子表格显示了针对每个CSM栖息地所有目标的审查结果，以及识别出强弱氮指标；关于这些电子表格的指南包含在附件2中。
* 最终评估矩阵——该Word文档提供了最终评估矩阵的副本。