In many ways, the tropical dry forest biome is the ‘invisible’ forest. Seasonally dry tropical forests (SDTFs) are found in the Americas, Africa, Asia and Australia, but they are not defined by a single physiography and the biogeographic origins of this biome are still under study (Dexter et al., 2015; Slik et al., 2018). In Latin America there is a wide array of names given to this forest type such as ‘bosque chiquitano’ in Bolivia, ‘chaco’ in Argentina or ‘caatinga’ in Brazil, while some SDTFs are referred to as miombo in Africa, and in Vietnam the deciduous dipterocarp forests are colloquially called ‘rừng khộp’ (‘rừng’ means forest and ‘khộp’ sounds like the dry leaves when you step on them). In many people’s imaginations and certainly in the popular press, tropical forests are dark, rainy and entangled ecosystems. In other words, many people equate tropical forests with rain forests. In fact, some people who live in lands that once supported SDTFs are unaware that their cities and towns used to be dry forests. Similarly, most young students from tropical and temperate latitudes alike who gravitate towards tropical forests get their start in rain forests. Compared to wet and moist tropical forests, SDTFs have lower annual rainfall and experience several months each year with little to no rainfall (Murphy & Lugo, 1986). As such, the structure, function, and diversity of these forests differs from other tropical forests with higher or lower seasonality (Fig. 1). SDTFs also contrast with savannas, which are characterized as mixtures of grass and trees with discontinuous canopy cover, and are maintained by fire (Dexter et al., 2018). Centuries of clearance for pastures and agriculture have greatly reduced the extent of SDTFs (Miles et al., 2006) to the point that they are considered one of the most threatened tropical biomes, with an estimated 45.8% of the biome converted to alternate land uses and a mere 7.6% of existing habitat under protected status (Hoekstra et al., 2005). However, as the dry forest biome is shrinking, interest in this diverse, threatened, and heterogeneous biome is growing (Pizano & García, 2014).

在许多方面，热带干旱森林生物群系是“看不见的”森林。在美洲、非洲、亚洲和澳大利亚发现了季节性干旱热带森林 (SDTF)，但它们并不是由单一的自然地理学定义的，而且该生物群落的生物地理起源仍在研究中 (Dexter et al ., 2015 ; Slik et al. ., 2018）。在拉丁美洲，这种森林类型有很多名称，例如玻利维亚的“bosque chiquitano”、阿根廷的“chaco”或巴西的“caatinga”，而一些 SDTF 在非洲和越南被称为 miombo落叶龙脑香林通俗地称为“rừng khộp”（“rừng”的意思是森林，“khộp”在你踩到它们时听起来像是干枯的树叶）。在许多人的想象中，当然在大众媒体中，热带森林是黑暗、多雨和纠缠的生态系统。换句话说，许多人将热带森林等同于热带雨林。事实上，一些生活在曾经支持 SDTF 的土地上的人并不知道他们的城镇曾经是干燥的森林。同样，来自热带和温带纬度的大多数年轻学生都喜欢热带森林，他们都是从热带雨林开始的。1986 年）。因此，这些森林的结构、功能和多样性不同于其他季节性较高或较低的热带森林（图1）。SDTFs 也与稀树草原形成对比，稀树草原的特征是草和树木的混合物，树冠覆盖不连续，并由火维持（Dexter等人，2018 年）。几个世纪以来对牧场和农业的清理大大减少了 SDTF 的范围（Miles等人，2006 年），以至于它们被认为是最受威胁的热带生物群落之一，估计有 45.8% 的生物群落转变为替代土地用途只有 7.6% 的现有栖息地处于受保护状态（Hoekstra等人，2005）。然而，随着干旱森林生物群落的缩小，人们对这种多样化、受威胁和异质的生物群落的兴趣正在增长（Pizano & García，2014 年）。