Science Rendue Possible

随机森林(Random forest)模型在2001年发表后得到广泛的关注。由于随机森林可以进行回归和判别等多种统计分析,而且不受正态性、方差齐性和自变量独立性等参数检验的前提条件的制约,其应用日益普遍,有被看作万能模型的趋势。实际上,随机森林是一种特点鲜明的模型,应用局部优化拟合观察值,在分析有偏效应关系的数据时,其结果往往不准确。本文以蝉科(Cicadidea)物种的分布数据为例,比较了随机森林在回归分析时与多元线性回归、广义可加模型和人工神经网络模型的差别,在判别分析时与线性判别分析的差别,强调了随机森林预测时的碎片化特点。结果显示随机森林在处理有多元共线性和交互作用的数据时,以及在判别…

Chase, B. M., A. Boom, A. S. Carr, M. Chevalier, L. J. Quick, G. A. Verboom, and P. J. Reimer. 2019. Extreme hydroclimate response gradients within the western Cape Floristic region of South Africa since the Last Glacial Maximum. Quaternary Science Reviews 219: 297–307. https://doi.org/10.1016/j.quascirev.2019.07.006

The Cape Floristic Region (CFR) is one of the world's major biodiversity hotspots, and much work has gone into identifying the drivers of this diversity. Considered regionally in the context of Quaternary climate change, climate stability is generally accepted as being one of the major factors promo…

Villaverde, T., P. González-Moreno, F. Rodríguez-Sánchez, and M. Escudero. 2017. Niche shifts after long-distance dispersal events in bipolar sedges (Carex, Cyperaceae). American Journal of Botany 104: 1765–1774. https://doi.org/10.3732/ajb.1700171

PREMISE OF THE STUDY: Bipolar species represent the greatest biogeographical disjunction on Earth, raising many questions about the colonization and adaptive processes behind such striking distribution. We investigated climatic niche differences of five Carex bipolar species in North and South Ameri…

Li, X., B. Li, G. Wang, X. Zhan, and M. Holyoak. 2020. Deeply digging the interaction effect in multiple linear regressions using a fractional-power interaction term. MethodsX 7: 101067. https://doi.org/10.1016/j.mex.2020.101067

In multiple regression Y ~ β0 + β1X1 + β2X2 + β3X1 X2 + ɛ., the interaction term is quantified as the product of X1 and X2. We developed fractional-power interaction regression (FPIR), using βX1M X2N as the interaction term. The rationale of FPIR is that the slopes of Y-X1 regression along the X2 gr…

Cross, A. T., T. A. Krueger, P. M. Gonella, A. S. Robinson, and A. S. Fleischmann. 2020. Conservation of carnivorous plants in the age of extinction. Global Ecology and Conservation 24: e01272. https://doi.org/10.1016/j.gecco.2020.e01272

Carnivorous plants (CPs)—those possessing specific strategies to attract, capture and kill animal prey and obtain nutrition through the absorption of their biomass—are harbingers of anthropogenic degradation and destruction of ecosystems. CPs exhibit highly specialised and often very sensitive ecolo…

Brightly, W. H., S. E. Hartley, C. P. Osborne, K. J. Simpson, and C. A. E. Strömberg. 2020. High silicon concentrations in grasses are linked to environmental conditions and not associated with C 4 photosynthesis. Global Change Biology 26: 7128–7143. https://doi.org/10.1111/gcb.15343

The uptake and deposition of silicon (Si) as silica phytoliths is common among land plants and is associated with a variety of functions. Among these, herbivore defense has received significant attention, particularly with regards to grasses and grasslands. Grasses are well known for their high sili…

Chevalier, M., B. M. Chase, L. J. Quick, L. M. Dupont, and T. C. Johnson. 2020. Temperature change in subtropical southeastern Africa during the past 790,000 yr. Geology 49: 71–75. https://doi.org/10.1130/G47841.1

Across the glacial-interglacial cycles of the late Pleistocene (~700 k.y.), temperature variability at low latitudes is often considered to have been negligible compared to changes in precipitation. However, a paucity of quantified temperature records makes this difficult to reliably assess. In this…

de Jesús Hernández-Hernández, M., J. A. Cruz, and C. Castañeda-Posadas. 2020. Paleoclimatic and vegetation reconstruction of the miocene southern Mexico using fossil flowers. Journal of South American Earth Sciences 104: 102827. https://doi.org/10.1016/j.jsames.2020.102827

Concern about the course of the current environmental problems has raised interest in investigating the different scenarios that have taken place in our planet throughout time. To that end, different methodologies have been employed in order to determine the different variables that compose the envi…

van Treuren, R., R. Hoekstra, R. Wehrens, and T. van Hintum. 2020. Effects of climate change on the distribution of crop wild relatives in the Netherlands in relation to conservation status and ecotope variation. Global Ecology and Conservation 23: e01054. https://doi.org/10.1016/j.gecco.2020.e01054

Crop wild relatives (CWR) are wild plant taxa that are genetically related to a cultivated species and are considered rich sources of useful traits for crop improvement. CWR are generally underrepresented in genebanks, while their survival in nature is not guaranteed. Inventories and risk analyses a…

Goodwin, Z. A., P. Muñoz-Rodríguez, D. J. Harris, T. Wells, J. R. I. Wood, D. Filer, and R. W. Scotland. 2020. How long does it take to discover a species? Systematics and Biodiversity 18: 784–793. https://doi.org/10.1080/14772000.2020.1751339

The description of a new species is a key step in cataloguing the World’s flora. However, this is only a preliminary stage in a long process of understanding what that species represents. We investigated how long the species discovery process takes by focusing on three key stages: 1, the collection …