One of the most valuable initiatives on massive availability of biodiversity data is the Global Biodiversity Information Facility, which is creating new opportunities to develop and test macroecological knowledge. However, the potential uses of these data are limited by the gaps and biases associated to large-scale distributional databases (the so-called Wallacean shortfall). Describing and quantifying these limitations are essential to improve knowledge on biodiversity, especially in poorly-studied groups, such as mosses. Here we assess the coverage of the publicly-available distributional information on Iberian mosses, defining its eventual biases and gaps. For this purpose, we compiled IberBryo v1.0, a database that comprises 82,582 records after processing and checking the geospatial and taxonomical information. Our results show the limitations of data and metadata of the publicly-available information. Particularly, ca. 42% of the records lacked collecting date information, which limits data usefulness for time coverage analyses and enlarges the existing knowledge gaps. Then we evaluated the overall coverage of several aspects of the spatial, temporal and environmental variability of the Iberian Peninsula. Through this assessment, we demonstrate that the publicly-available information on Iberian mosses presents significant biases. Inventory completeness is strongly conditioned by the recorders' survey bias, particularly in northern Portugal and eastern Spain and the spatial pattern of surveys is also biased towards mountains. Besides, the temporal pattern of survey effort intensifies from 1970 onwards, encompassing a progressive increase in the geographic coverage of the Iberian Peninsula. Although we just found 5% of well-surveyed cells of 30’ of resolution over the 1970-2018 period, they cover about a fifth of the main climatic gradients of the Iberian Peninsula, which provides a fair – though limited – coverage. Yet, the well-surveyed cells are biased towards anthropised areas and some of them are located in areas under intense land-use changes, mainly due to the wood-fires of the last decade. Despite the overall increase, we found a noticeable gap of information in the south-west of Iberia, the Ebro river basin and the inner plateaus. All these gaps and biases call for a careful use of the available distributional data of Iberian mosses for biogeographical and ecological modelling analysis. Further, our results highlight the necessity of incorporating several good practices to increase the coverage of high-quality information. These good practices include digitalisation of specimens and metadata information, improvement on the protocols to get accurate data and metadata or revisions of the vouchers and recorders' field notebooks. These procedures are essential to improve the quality and coverage of the data. Finally, we also encourage Iberian bryologists to establish a series of re-surveys of classical localities that would allow updating the information on the group, as well as to design their future surveys considering the most important information gaps on IberBryo.

中文翻译：

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评估伊比利亚苔藓的公开分布信息中的时空偏差和差距

关于大规模获取生物多样性数据的最有价值的举措之一是全球生物多样性信息基金，这为开发和测试宏观生态学知识创造了新的机会。但是，这些数据的潜在用途受到与大型分布数据库相关的空白和偏差（所谓的华莱士不足）的限制。描述和量化这些局限性对于提高对生物多样性的知识至关重要，尤其是在对青苔等未充分研究的群体中。在这里，我们评估了伊比利亚青苔公开发行的分布信息的覆盖范围，定义了其最终的偏见和差距。为此，我们对IberBryo v1.0进行了编译，该数据库在处理和检查地理空间和分类信息后包含82582条记录。我们的结果显示了公开信息的数据和元数据的局限性。特别是，大约。42％的记录缺少收集日期信息，这限制了数据对时间覆盖率分析的有用性，并扩大了现有的知识差距。然后，我们评估了伊比利亚半岛时空，环境和环境变化几个方面的整体覆盖范围。通过这项评估，我们证明了有关伊比利亚青苔的公开信息存在重大偏见。记录员的调查偏向在很大程度上决定了存货的完整性，特别是在葡萄牙北部和西班牙东部，调查的空间格局也偏向山脉。此外，从1970年开始，调查工作的时间格局不断加剧，包括伊比利亚半岛地理覆盖范围的逐步扩大。尽管在1970-2018年期间，我们只发现5％分辨率为30'的测量良好的细胞，但它们覆盖了伊比利亚半岛主要气候梯度的约五分之一，尽管覆盖范围有限，但覆盖范围相当。然而，调查充分的牢房偏向于人为化的地区，其中一些位于土地利用变化剧烈的地区，这主要是由于最近十年的柴火所致。尽管总体有所增加，但我们发现在伊比利亚西南部，埃布罗河流域和内陆高原地区存在明显的信息鸿沟。所有这些差距和偏见要求对伊比利亚苔藓的可用分布数据进行仔细的利用，以进行生物地理和生态模型分析。进一步，我们的研究结果突出表明，有必要采用几种良好做法来增加高质量信息的覆盖范围。这些良好实践包括对标本和元数据信息进行数字化，改进协议以获取准确的数据和元数据或对凭证和记录仪的现场笔记本进行修订。这些过程对于提高数据的质量和覆盖范围至关重要。最后，我们还鼓励伊比利亚冷冻学家建立一系列经典地点的重新调查，以更新有关该小组的信息，并考虑到IberBryo上最重要的信息空白来设计他们的未来调查。改进协议以获取准确的数据和元数据，或者对凭证和记录器的现场笔记本进行修订。这些过程对于提高数据的质量和覆盖范围至关重要。最后，我们还鼓励伊比利亚冷冻学家建立一系列经典地点的重新调查，以更新有关该小组的信息，并考虑到IberBryo上最重要的信息空白来设计他们的未来调查。改进协议以获取准确的数据和元数据或对凭证和记录器的现场笔记本进行修订。这些过程对于提高数据的质量和覆盖范围至关重要。最后，我们还鼓励伊比利亚冷冻学家建立一系列经典地点的重新调查，以更新有关该小组的信息，并考虑到IberBryo上最重要的信息空白来设计他们的未来调查。