馆藏标本是分类学研究的主要凭证, 对特定类群标本的采集信息进行细致整理和分析, 有助于理解该类群研究的历史、现状和不足。此外, 结合最新的系统学研究成果和相应的环境数据构建生态位模型, 可以加深人们对特定类群分类与分布状况的认识。被子植物的分类鉴定常基于繁殖性状进行, 然而, 竹类植物一般进行克隆繁殖, 只有在经过长期的营养生长之后, 才会进行有性生殖并同时死亡。因此, 国内的竹类标本大多仅记录了营养性状, 具有繁殖性状的标本数量稀少。由于这一特殊的生物学习性, 竹类植物是当今分类学研究中最为困难的类群之一。本研究基于全国竹类植物馆藏标本的采集数据, 分析了我国竹类标本的采集和保藏现状; 利用比值法和斜率法从采集地理偏差和采集类群偏差两方面评估了竹类植物标本的采集完整度; 结合气候数据, 利用模型模拟的方法分析了影响不同竹类分支分布的主要因素。采集信息分析结果表明, 国内标本馆对竹类标本的收集和保藏存在很大的不均衡性, 且对研究团队具有较高的依赖性; 其次竹类标本的采集量的变化较好地反映了国内植物分类学研究的历史; 而对类群和地理采集完整度的评估结果表明, 中国竹类标本的采集和整理工作仍任重道远。模型模拟结果表明, 温度限定了竹类植物两大分支各自的分布北界, 水分对温带木本竹类分支(temperate woody bamboos, TWB)的限制作用比旧世界热带木本竹类分支(paleotropical woody bamboos, PWB)强, 而温度对PWB的限制性更强。生态位模拟的结果进一步显示, 中国温带和旧世界热带木本竹类两大分支的适生区出现了明显的分化, 但在亚热带区域仍有部分重叠。植物标本记录了特定类群在时间和空间上的分布格局, 相关的信息一方面可以促进物种灭绝风险评估、可持续利用和综合保护, 另一方面也可助力大尺度生物多样性分布格局及全球变化对多样性的影响研究。

Aims: Herbarium specimens are important for taxonomic research. Analyses of these specimens are important for understanding their history, taxonomic status, and existing gaps in knowledge. In addition, such analyses allow for deeper insights into the distribution and classification of specific taxa using phylogenetic and niche modeling techniques. In most cases, identification of herbarium specimens is based on the reproductive traits. However, bamboo is a long-lived clonal plant that undergoes flowering followed by simultaneous death after a long-term growth period. As a result, most bamboo specimens only contain vegetative characters, and the information on reproductive traits remains sparse. As a result of this unique life history, bamboos are one of the most difficult taxa for taxonomic research. Here, we aim to examine the status of collection of bamboo herbarium specimens in China and document existing biases. Furthermore, we also aim to evaluate the main drivers for the distribution of the two major clades of bamboos (temperate woody bamboos, TWB; paleotropical woody bamboos, PWB).
Methods: Here, we used collection data from the major herbaria of China to analyze the current collection and preservation status of bamboo specimens. The completeness of the collection was evaluated by the ratio and slope methods with respect to geographical and group deviations. In combination with climate data from WorldClim, we used model simulations to identify the main factors affecting the distribution of bamboo.
Results: The results from the analysis on collection information indicate that there is a great unevenness in the collection and conservation of bamboo specimens in domestic herbaria. These aspects are highly dependent on the vigor of research teams. Second, variation in the collection of bamboo specimens is a clear reflection of the history of plant taxonomy research in China. Additionally, the results from the assessment of taxa and the completeness of geographic collection indicate that much work still remains for the collection and collation of bamboo specimens in China. The analysis of model simulations showed that the distribution of the two major clades of bamboos in China is mainly limited by a low temperature. Moisture had a greater effect on the distribution of TWB than on PWB, while the effect of temperature was higher for PWB. Results from niche modeling further indicate that the PWB and the TWB in China have diverged in area use with only some overlap in subtropical areas.
Conclusions: Our study highlights the geographic distribution and taxa collecting biases in herbarium specimens of bamboos in China, as well as the significance of climate variables for the distributions of temperate and paleotropical woody bamboos. Our findings also indicate some poorly sampled areas, which should be preferential targets for future biodiversity surveys. Furthermore, as millions of digitalized herbarium specimens become available online and will play an important role in revealing large-scale diversity patterns. Such effort can improve the forecasts of the impacts of climatic change on the biodiversity.