Biomes

Just like its climate, Earth’s land cover varies widely between regions. Some regions are characterized by deserts, while in others wetlands predominate. Boreal forests, also called taiga, cover much of the planet’s northern latitudes, while tropical forests are a common feature in equatorial countries. These diverse types of land cover can be further broken down into “ecoregions”—large expanses of land, each with a distinct biological and environmental character. Mapping land cover often involves defining a set of ecoregions and determining which parts of Earth’s surface match the criteria for each ecoregion. To define a set of ecoregions, scientists may supplement existing work, such as maps of species distribution and vegetation types, with new insights and data gathered from regional experts. The land cover types included in this map layer are based on biogeographic research (sources listed here), a framework last updated in 2017 that defines more than 846 land-based ecoregions within about a dozen biomes or habitat types. This map layer represents those broader categories, like deserts and tropical forests. A couple of tips for navigating this layer: 1) If a region is shaded entirely in the color representing a particular biome, it indicates that that biome is the predominant one, but there may be characteristics of other biomes present as well. 2) The actual borders between biomes are often large regions unto themselves rather than precise lines. There’s even a name for these transition areas: ecotones! This map layer from RESOLVE Biodiversity and Wildlife Solutions includes the following biomes: Boreal Forests/Taiga: widespread in northern Russia and Canada, boreal forests are typically home to lots of conifers, mosses, and lichens Deserts and Xeric Shrubland: the evaporation rate may be greater than the rate of precipitation in these dry regions, exemplified by the Sahara and Gobi Flooded Grasslands and Savannas: like mangroves, this biome is waterlogged land that may support grasses, shrubs, and trees; the Everglades of South Florida are an example Mangroves: the mangrove tree dominates these coastal regions, which frequently lie within intertidal zones Mediterranean Forests, Woodlands, and Scrub: these wooded regions are known for their hot, dry summers and cool, wet winters Montane Grasslands and Shrublands: this biome, which features waxy, hairy plants, defines the Tibetan Plateau and parts of the Andes Bare Earth: occurring largely in Earth’s polar regions, bare earth includes tundra, a type of cold desert with sparse vegetation Temperate Broadleaf and Mixed Forests: this biome may include oak, beech, and maple trees; in contrast to tropical forests, biodiversity here is usually concentrated near the forest floor Temperate Coniferous Forests: this biome has warm summers and cool winters with a wide variety of plant life, including either needleleaf or broadleaf evergreen trees Temperate Grasslands, Savannas, and Shrubland: trees are less common in this biome, which goes by many names—such as prairie, pampas, and veld Tropical and Subtropical Coniferous Forests: located mostly in North and Central American regions, with low precipitation and moderate temperature variability, making it ideal for needleleaf conifers to grow Tropical and Subtropical Dry Broadleaf Forests: this biome is characterized by year-round warm temperatures but seasonal precipitation that results in long dry periods and features drought-deciduous trees, for example, the forests of southern Mexico or central India Tropical and Subtropical Grasslands, Savannas, and Shrublands: prominent in East Africa, these regions are often too dry to support much tree growth Tropical and Subtropical Moist Broadleaf Forests: common in the region between the Tropics of Cancer and Capricorn, this biome has steady temperatures year-round and high precipitation, allowing for evergreen and semi-evergreen trees Tundra: found near the poles, this biome is characterized by a cold desert, dark winters, and sunny summers with low-growing vegetation与地球气候特征相似，全球陆地覆盖类型因区域差异呈现显著分异。部分区域以荒漠为典型特征，另有诸多区域则以湿地为主导。北方针叶林（Boreal Forests，又称泰加林（taiga））覆盖了地球绝大多数高纬度北部区域，而热带森林则是赤道国家的典型景观。 这些丰富多样的陆地覆盖类型可进一步划分为“生态区（ecoregions）”——即拥有独特生物与环境属性的大面积陆地单元。开展陆地覆盖制图工作时，通常需要先界定一套生态区体系，再明确地球表面哪些区域符合各生态区的判定标准。 为构建生态区体系，科研人员可借助区域专家提供的新认知与实测数据，对既有研究成果——如物种分布与植被类型地图——进行补充完善。本图层所采用的陆地覆盖类型基于生物地理学研究（数据源详见此处），该分类框架最后更新于2017年，在约12个生物群系（biomes）或生境类型范围内界定了846余个陆地生态区。本图层即展示了这些更为宽泛的生态大类，例如荒漠与热带森林。 本图层使用指南如下： 1）若某区域完全以代表某一生物群系的颜色着色，则表明该生物群系为该区域的主导类型，但区域内仍可能存在其他生物群系的特征片段。 2）生物群系间的实际边界往往并非精确的线条，而是一片过渡区域。这类过渡地带更有专属名称：生态交错带（ecotones）！ 本图层由RESOLVE Biodiversity and Wildlife Solutions团队制作，涵盖以下生物群系： 1. 北方针叶林/泰加林：广泛分布于俄罗斯北部与加拿大区域，该群落以大量针叶树、苔藓与地衣为典型特征。 2. 荒漠与干旱灌丛：此类干旱区域的蒸发量通常高于降水量，以撒哈拉沙漠与戈壁沙漠为典型代表。 3. 淹水草原与稀树草原：与红树林群落类似，该生物群系处于积水环境中，可支撑草本、灌木与乔木生长，美国南佛罗里达州的大沼泽地即为典型案例。 4. 红树林：此类沿海区域以红树植物为优势物种，且大多位于潮间带范围内。 5. 地中海森林、林地与灌丛：该林区以夏季炎热干燥、冬季凉爽湿润为显著气候特征。 6. 山地草原与灌丛：该生物群系以覆有蜡质或绒毛的植物为特征，涵盖青藏高原与安第斯山脉部分区域。 7. 裸露地表：主要分布于地球极地区域，包含植被稀疏的寒漠——苔原（tundra）。 8. 温带阔叶与混交林：该生物群系以栎树、山毛榉与枫树为常见树种；与热带森林不同，其生物多样性通常集中于林下层区域。 9. 温带针叶林：该生物群系夏季温暖、冬季凉爽，拥有丰富的植物类群，包含针叶或阔叶常绿树种。 10. 温带草原、稀树草原与灌丛：该生物群系中树木较为稀少，拥有诸多别称，如北美大草原（prairie）、南美潘帕斯草原（pampas）与非洲稀树草原（veld）。 11. 热带与亚热带针叶林：主要分布于北美与中美洲区域，降水量较低且气温波动幅度适中，非常适宜针叶树生长。 12. 热带与亚热带干旱阔叶林：该生物群系全年气温温暖，但降水存在季节性差异，会形成漫长的旱季，以旱落叶乔木为典型特征，例如墨西哥南部与印度中部的森林。 13. 热带与亚热带草原、稀树草原与灌丛：该群落广泛分布于东非区域，通常因气候过于干旱而难以支撑大规模乔木生长。 14. 热带与亚热带湿润阔叶林：广泛分布于北回归线与南回归线之间的区域，全年气温稳定且降水量充沛，适宜常绿与半常绿乔木生长。 15. 苔原：分布于极地附近区域，属于寒漠类型，冬季漫长昏暗，夏季日照充足，植被以低矮类群为主。