High resolution implementation of the Holdridge Life Zone system with transitional zones and altitudinal belts

Paper submitted, full text forthcoming.Interactive view available at: https://aenikolopov.projects.earthengine.app/view/hlz<br>Code available: https://github.com/armenenikolopov/HoldridgeLifeZoneMap<br>ABSTRACT:<br>The Holdridge Life Zone (HLZ) system is a widely used framework for ecological classification, yet existing implementations suffer from coarse resolution and inaccurate evapotranspiration estimates. We present the first global 30-arcsecond (~1 km²) global HLZ map, a 3600x improvement over currently available models, addressing critical limitations of previous models. This high-resolution approach is particularly important in topographically complex regions such as the Tropical Andes, where elevation-driven climate changes occur over short distances and are missed in lower-resolution models. Additionally, many transitional life zones predicted by Holdridge are only visible when mapped at fine scales, making this model especially useful for field-based ecological studies and herbarium specimen attribution rather than broad-scale climate applications.<br>A key weakness of the traditional HLZ system is its reliance on a simplified evapotranspiration approximation, which we demonstrate to be several-fold inaccurate outside the tropics and significantly flawed even within them. We provide the first quantitative assessment of where these errors are most severe and introduce a high-resolution alternative using the Penman-Monteith model for improved classification accuracy, particularly in non-tropical regions. These resulting classification differences are discussed. To support broad adoption, we provide open-source code, downloadable datasets, and an interactive web tool for zone determination. This refined HLZ implementation enables more precise ecological fieldwork, floristic studies, biogeographical studies, and climate impact assessments at local scales.<br><br>

论文已提交，全文待发表。交互式可视化工具可访问：https://aenikolopov.projects.earthengine.app/view/hlz<br>代码开源地址：https://github.com/armenenikolopov/HoldridgeLifeZoneMap<br>摘要：<br>霍尔德里奇生命带（Holdridge Life Zone, HLZ）系统是应用广泛的生态分类框架，但现有实现方案存在分辨率粗糙、蒸散量估算不准确的缺陷。本研究发布全球首幅30角秒（约1平方千米）分辨率的霍尔德里奇生命带地图，相较于现有模型分辨率提升3600倍，解决了既往模型的关键局限。该高分辨率方案在地形复杂区域（如热带安第斯山脉）尤为关键——这类区域内海拔驱动的气候变化仅发生在短距离范围内，低分辨率模型无法捕捉此类变化。此外，霍尔德里奇模型预测的诸多过渡性生命带仅在精细尺度制图中才可显现，因此本模型尤其适用于野外生态研究与标本馆标本归属鉴定，而非大范围气候应用。<br><br>传统霍尔德里奇生命带系统的核心缺陷之一是依赖简化的蒸散量近似估算方法——本研究证明，该方法在热带以外区域误差可达数倍，即便在热带区域内也存在显著缺陷。本研究首次对该误差最严重的区域进行了定量评估，并引入基于彭曼-蒙特斯（Penman-Monteith）模型的高分辨率替代方案，以提升分类精度，尤其在非热带区域。本文还对由此产生的分类差异进行了讨论。为推动该成果的广泛应用，本研究提供了开源代码、可下载数据集以及用于生命带判定的交互式网页工具。经优化后的霍尔德里奇生命带模型实现方案，可支持更精准的野外生态调查、区系研究、生物地理学研究以及局地尺度气候影响评估。