Science Enabled by Specimen Data

Rautela, K., A. Kumar, S. K. Rana, A. Jugran, and I. D. Bhatt. 2024. Distribution, Chemical Constituents and Biological Properties of Genus Malaxis. Chemistry & Biodiversity. https://doi.org/10.1002/cbdv.202301830

The genus Malaxis (family Orchidaceae), comprises nearly 183 species available across the globe. The plants of this genus have long been employed in traditional medical practices because of their numerous biological properties, like the treatment of infertility, hemostasis, burning sensation, bleeding diathesis, fever, diarrhea, dysentery, febrifuge, tuberculosis, etc. Various reports highlight their phytochemical composition and biological activities. However, there is a lack of systematic review on the distribution, phytochemistry, and biological properties of this genus. Hence, this study aims to conduct a thorough and critical review of Malaxis species, covering data published from 1965 to 2022 with nearly 90 articles. Also, it examines different bioactive compounds, their chemistry, and pharmacotherapeutics as well as their traditional uses. A total of 191 unique compounds, including the oil constituents were recorded from Malaxis species. The highest active ingredients were obtained from Malaxis acuminata (103) followed by Malaxis muscifera (50) and Malaxis rheedei (33). In conclusion, this review offers an overview of the current state of knowledge on Malaxis species and highlights prospects for future research projects on them. Additionally, it recommends the promotion of domestication studies for rare medicinal orchids like Malaxis and the prompt implementation of conservation measures.

Xiao, S., S. Li, J. Huang, X. Wang, M. Wu, R. Karim, W. Deng, and T. Su. 2024. Influence of climate factors on the global dynamic distribution of Tsuga (Pinaceae). Ecological Indicators 158: 111533. https://doi.org/10.1016/j.ecolind.2023.111533

Throughout the Quaternary period, climate change has significantly influenced plant distribution, particularly affecting species within the genus Tsuga (Endl.) Carrière. This climatic impact ultimately led to the extinction of all Tsuga species in Europe. Today, there are ten recognized species of Tsuga worldwide, one of listed as a vulnerable species and four as near-threatened species. The genus Tsuga exhibits a disjunctive distribution in East Asia (EA), eastern North America (ENA), and western North America (WNA). It is crucial to comprehend the mechanisms underlying these distributional changes and to identify key climate variables to develop effective conservation strategies for Tsuga under future climate scenarios. In this study, we applied the maximum entropy (MaxEnt) model by combining distribution data for Tsuga with abundant pollen fossil data. Our objective was to investigate the climate factors that shape the distribution of Tsuga, identify climate thresholds, and elucidate distribution dynamics in the context of significant climate changes over the past 1070 thousand years (ka). Our findings highlight the pivotal role of precipitation as the key climate factor affecting the distribution of Tsuga. Specifically, in EA, summer precipitation was the key driver, while in North America (NA), winter precipitation exerted greater importance. Moreover, we observed similarities in climatic requirements between Tsuga species in Europe and EA, and declines in summer precipitation and winter temperature were major factors contributing to the extinction of Tsuga species in Europe. Quaternary glacial and interglacial fluctuations exerted substantial impacts on Tsuga distribution dynamics. The disappearance of Tsuga species in the Korean Peninsula may have occurred during the LGM (Last Glacial Maximum). The potential suitable area for Tsuga species in EA expanded during the cold periods, while in NA, it contracted. In the future, climate change may result Tsuga distribution area contraction in both the EA and NA. Our study has identified distinct response patterns of Tsuga in various geographic regions to Quaternary climate change and offers corresponding suggestions for Tsuga conservation. In the future, it will be imperative to prioritize the conservation of natural Tsuga distributions in EA and NA, with a focus on the impacts of precipitation fluctuation on the dynamic distribution of this genus.

岛屿因具有明确的地理边界, 是检验多个生态学过程如何构建生物多样性的理想平台之一。岛屿属性、气候因素、人 类干扰等通过影响物种选择、扩散等过程, 进而影响着岛屿生物多样性格局。目前对于岛屿植物丰富度格局如何受这些因素 的共同作用的认识仍不充分, 尤其是在人类干扰较强的海岛。本文基于我国第一大群岛舟山群岛92个岛屿较完整的种子植物 分布数据, 采用一般线性回归和广义线性模型(伪泊松分布)定量评估岛屿属性(面积、隔离度、形状指数)、气候(温度、降水 及其季节性)和人类干扰对本土植物总丰富度及不同生长型、叶物候型植物丰富度格局的影响, 采用beta回归分析常绿阔叶木 本比率(常绿阔叶木本植物丰富度/所有阔叶木本植物丰富度)的影响因素。结果发现: 92个岛屿共记录本土植物1,158种, 其中 乔木108种、灌木318种、草本732种; 岛屿面积是对植物总丰富度影响最大的因子, 其次是年降水量和隔离度; 乔木丰富度随 隔离度增加而减少的趋势比灌木和草本更明显; 常绿阔叶和落叶阔叶木本植物丰富度格局与总体基本一致, 年降水量对常绿 阔叶木本的影响大于落叶阔叶木本, 但常绿阔叶木本比率仅受温度季节性的强烈影响。岛屿面积、年降水量、温度季节性等 是塑造舟山群岛所有植物及其不同功能型组(生长型、叶物候型)植物丰富度格局的主要决定因素。

Zhang, H., W. Guo, and W. Wang. 2023. The dimensionality reductions of environmental variables have a significant effect on the performance of species distribution models. Ecology and Evolution 13. https://doi.org/10.1002/ece3.10747

How to effectively obtain species‐related low‐dimensional data from massive environmental variables has become an urgent problem for species distribution models (SDMs). In this study, we will explore whether dimensionality reduction on environmental variables can improve the predictive performance of SDMs. We first used two linear (i.e., principal component analysis (PCA) and independent components analysis) and two nonlinear (i.e., kernel principal component analysis (KPCA) and uniform manifold approximation and projection) dimensionality reduction techniques (DRTs) to reduce the dimensionality of high‐dimensional environmental data. Then, we established five SDMs based on the environmental variables of dimensionality reduction for 23 real plant species and nine virtual species, and compared the predictive performance of those with the SDMs based on the selected environmental variables through Pearson's correlation coefficient (PCC). In addition, we studied the effects of DRTs, model complexity, and sample size on the predictive performance of SDMs. The predictive performance of SDMs under DRTs other than KPCA is better than using PCC. And the predictive performance of SDMs using linear DRTs is better than using nonlinear DRTs. In addition, using DRTs to deal with environmental variables has no less impact on the predictive performance of SDMs than model complexity and sample size. When the model complexity is at the complex level, PCA can improve the predictive performance of SDMs the most by 2.55% compared with PCC. At the middle level of sample size, the PCA improved the predictive performance of SDMs by 2.68% compared with the PCC. Our study demonstrates that DRTs have a significant effect on the predictive performance of SDMs. Specifically, linear DRTs, especially PCA, are more effective at improving model predictive performance under relatively complex model complexity or large sample sizes.

Qiu, L., Q.-L. Fu, H. Jacquemyn, K. S. Burgess, J.-J. Cheng, Z.-Q. Mo, X.-D. Tang, et al. 2023. Contrasting range changes of Bergenia (Saxifragaceae) species under future climate change in the Himalaya and Hengduan Mountains Region. Theoretical and Applied Climatology. https://doi.org/10.1007/s00704-023-04746-0

The Himalaya and Hengduan Mountains (HDM) are recognized as two global biodiversity hotspots, harboring the world’s richest alpine flora. However, to what extent the distribution of alpine plants here is affected by climate change remains largely unknown. Bergenia (Saxifragaceae) are perennial medicinal herbs mainly distributed in the Himalaya-HDM region. In this study, we used bioclimatic data for current and future climate scenarios to assess the impact of climate change on the potential distribution of three Bergenia (Saxifragaceae) species. Our results revealed that the geographical distribution of the studied Bergenia species is primarily influenced by precipitation and elevation. By 2090, the three Bergenia species are expected to show contrasting range changes. The western Himalayan alpine species Bergenia stracheyi is expected to expand its range with 21.93 and 17.36% under the optimistic (SSP1-2.6) and moderate (SSP2-4.5) climate change scenario, respectively, while its distribution will shrink by 5.26% under the pessimistic scenario (SSP5-8.5). The Himalayan mid-elevation species B. ciliata is expected to expand its range from 142.42 to 157.14%. In contrast, the distribution range of the east Himalaya-HDM alpine species B. purpurascens is expected to shrink with 34.88 to 47.24%, with most of the habitats in the southeast chains of the HDM at lower elevation summits being lost. In addition, all three Bergenia species are projected to shift their ranges to higher elevations in response to temperature increases. Overall, we conclude that alpine plants may be more vulnerable to climate change than their congeners at lower elevations, supporting the “nowhere to go” hypothesis.

Wan, Q., K. Huang, S.-F. Chen, F. Boyer, P. Taberlet, H. Li, C. Chen, et al. 2023. Fagus diversification in China in relation to East Asian monsoon evolution. Quaternary Science Reviews 320: 108350. https://doi.org/10.1016/j.quascirev.2023.108350

When and how the extraordinary species diversity in subtropical East Asia formed is intensely debated, and the available evidence is often inconsistent. In this study, we evaluate the effects of pre- and post- Quaternary events on the evolutionary and biogeographic history of Chinese beech (Fagus species that now occur in China) to gain new insights into the historical establishment and future fate of the East Asian subtropical forest (EASF). A series of approaches and datasets were used to reconstruct biogeographic and evolutionary history of the Chinese beech. They include phylogeography based on the polymorphisms of the complete chloroplast genomes, species distribution models, and a large palaeobiogeographic dataset including 59 pre-Quaternary fossil records, 296 Quaternary fossil records and 3515 modern pollen records. Our multidisciplinary approach suggests that (i) Chinese beech has dispersed to subtropical East Asia and diversified in the early Miocene when the Asian monsoon (AM) intensified; (ii) the last post-glacial warming resulted in limited poleward displacement but significant contraction at southern and lower elevations; (iii) the poleward dispersal of Chinese beech was limited by drought in the early growing season in temperate China, controlled by the East Asian summer monsoon. Our results support the hypothesis that the establishment of the EASF is closely related to the evolution of the AM. More importantly, we suggest that with continued climate warming (e.g., during the last post-glacial period or under current climate change), the monsoon probably hindered rather than promoted the persistence of deciduous beech species, resulting in a decline in species richness.

史前人类与其生存环境,特别是与植被之间的相互作用一直是人们关注的焦点。气候变化与人类活动对植 被覆盖格局的塑造均有重要影响,厘清植被分布及其植被变化背后的气候或人为因素,有助于更好地认识人类活 动 对 植 被 环 境 的 影 响 程 度 与 范 围 。 本 研 究 对 青 藏 高 原 松 属 (Pinusspp.)植 被 适 生 区 分 布 动 态 历 史 进 行 了 物 种 分 布 模型模拟,并结合环境考古学、古生态学等多学科方法,探究青藏高原松属植被分布变化历史及其驱动因素。结 果表明,基于最大熵(MaxEnt)算法并结合 R语言包 ENMeval来优化参数设置的模型性能表现良好且稳健,较为 准确模拟松属在青藏高原地区不同时期的适生区分布动态。高原上松属适生区在末次冰盛期(LGM)分布最小, 仅在东缘的河谷局地;在全新世早、中期分布达到最大值,到全新世晚期部分区域分布缩小,高原东北部高度适 生区向 2500ma.s.l.上下的低海拔谷地收缩,整体上与高原气候变化趋势大体一致。结合化石花粉、木炭等证据 表明,全新世中晚期以前,人类对高原松属植被影响总体尚不显著;进入全新世晚期,农业技术的进步促使高原 东北部人口快速增加,高原上现已发现的古遗址也高度集中在此。结合多项考古证据表明,人类对松属为代表的 林木资源规模化开发行为开始显著干扰了当地植被,人类对松属等针叶林木材资源的利用可能是该地区树种向 阔叶林树种演替的重要驱动因素之一。

Rodríguez-Merino, A. 2023. Identifying and Managing Areas under Threat in the Iberian Peninsula: An Invasion Risk Atlas for Non-Native Aquatic Plant Species as a Potential Tool. Plants 12: 3069. https://doi.org/10.3390/plants12173069

Predicting the likelihood that non-native species will be introduced into new areas remains one of conservation’s greatest challenges and, consequently, it is necessary to adopt adequate management measures to mitigate the effects of future biological invasions. At present, not much information is available on the areas in which non-native aquatic plant species could establish themselves in the Iberian Peninsula. Species distribution models were used to predict the potential invasion risk of (1) non-native aquatic plant species already established in the peninsula (32 species) and (2) those with the potential to invade the peninsula (40 species). The results revealed that the Iberian Peninsula contains a number of areas capable of hosting non-native aquatic plant species. Areas under anthropogenic pressure are at the greatest risk of invasion, and the variable most related to invasion risk is temperature. The results of this work were used to create the Invasion Risk Atlas for Alien Aquatic Plants in the Iberian Peninsula, a novel online resource that provides information about the potential distribution of non-native aquatic plant species. The atlas and this article are intended to serve as reference tools for the development of public policies, management regimes, and control strategies aimed at the prevention, mitigation, and eradication of non-native aquatic plant species.

Graham, C. D. K., E. J. Forrestel, A. L. Schilmiller, A. T. Zemenick, and M. G. Weber. 2023. Evolutionary signatures of a trade-off in direct and indirect defenses across the wild grape genus Vitis. Evolution. https://doi.org/10.1093/evolut/qpad140

Evolutionary correlations between chemical defense and protection by mutualist bodyguards have been long predicted, but tests of these pattern remain rare. We use a phylogenetic framework to test for evolutionary correlations indicative of trade-offs or synergisms between direct defense in the form of plant secondary metabolism, and indirect defense in the form of leaf domatia, across 33 species in the wild grape genus, Vitis. We also performed a bioassay with a generalist herbivore to associate our chemical phenotypes with herbivore palatability. Finally, we tested whether defensive traits correlate with the average abiotic characteristics of each species’ contemporary range and whether these correlations were consistent with plant defense theory. We found a negative evolutionary correlation between domatia size and the diversity of secondary metabolites in Vitis leaf tissue across the genus, and also that leaves with a higher diversity and richness of secondary metabolites were less palatable to a generalist herbivore, consistent with a trade-off in chemical and mutualistic defense investment. Predictions from plant defense theory were not supported by associations between investment in defense phenotypes and abiotic variables. Our work demonstrates an evolutionary pattern indicative of a trade-off between indirect and direct defense strategies across the Vitis genus.

Hill, A., M. F. T. Jiménez, N. Chazot, C. Cássia‐Silva, S. Faurby, L. Herrera‐Alsina, and C. D. Bacon. 2023. Apparent effect of range size and fruit colour on palm diversification may be spurious. Journal of Biogeography. https://doi.org/10.1111/jbi.14683

Aim Fruit selection by animal dispersers with different mobility directly impacts plant geographical range size, which, in turn, may impact plant diversification. Here, we examine the interaction between fruit colour, range size and diversification rate in palms by testing two hypotheses: (1) species with fruit colours attractive to birds have larger range sizes due to high dispersal ability and (2) disperser mobility affects whether small or large range size has higher diversification, and intermediate range size is expected to lead to the highest diversification rate regardless of disperser. Location Global. Time Period Contemporary (or present). Major Taxa Studied Palms (Arecaceae). Methods Palm species were grouped based on likely animal disperser group for given fruit colours. Range sizes were estimated by constructing alpha convex hull polygons from distribution data. We examined disperser group, range size or an interaction of both as possible drivers of change in diversification rate over time in a likelihood dynamic model (Several Examined State-dependent Speciation and Extinction [SecSSE]). Models were fitted, rate estimates were retrieved and likelihoods were compared to those of appropriate null models. Results Species with fruit colours associated with mammal dispersal had larger ranges than those with colours associated with bird dispersal. The best fitting SecSSE models indicated that the examined traits were not the primary driver of the heterogeneity in diversification rates in the model. Extinction rate complexity had a marked impact on model performance and on diversification rates. Main Conclusions Two traits related to dispersal mobility, range size and fruit colour, were not identified as the main drivers of diversification in palms. Increased model extinction rate complexity led to better performing models, which indicates that net diversification should be estimated rather than speciation alone. However, increased complexity may lead to incorrect SecSSE model conclusions without careful consideration. Finally, we find palms with more mobile dispersers do not have larger range sizes, meaning other factors are more important determinants of range size.