Data from: Tree species composition, breeding systems, pollination and dispersal syndromes in three forest successional stages in a tropical dry forest in Mesoamerica

Tropical dry forests (TDF) in Mesoamerica are highly endangered by the expansion of human activities (e.g., agriculture and cattle ranching). In contrast, TDF in Costa Rica have experienced outstanding restoration due to changes in economic and conservation policies. Currently TDF landscapes in Costa Rica are a mosaic of different successional stages. Tree breeding systems and pollination and dispersal syndromes are key elements for understanding restoration processes in TDFs. In this study we describe and compare tree species composition and diversity in three TDF successional stages (early, intermediate and late) in Guanacaste, Costa Rica. We describe for the first time tree species breeding systems and pollination and dispersal syndromes for the largest and most significant TDF remnant in Mesoamerica. We set up nine plots, three per successional stage, and we measured and identified 1,072 trees from 96 species. Species richness and diversity indices were higher for the intermediate stage. Monoecy was the most common breeding system, as in other tropical life zones. Insects were the dominant pollinators, facilitated by the trees’ small inflorescences. Wind was found to be not only the next most influential pollinator, mainly in open and disturbed early forests, but also it was also a good seed dispersal agent. As TDF age increases so does the relevancy of birds and mammals as dispersers; the late stage therefore has more tree species with adaptations to these dispersers.

中美洲的热带干旱林（Tropical dry forests, TDF）正因人类活动（如农业与养牛业）的扩张而面临高度濒危的困境。与之形成鲜明对比的是，哥斯达黎加境内的热带干旱林因经济政策与保护政策的变革，实现了卓越的生态修复。当前哥斯达黎加的热带干旱林景观呈现为不同演替阶段的镶嵌式分布格局。树木繁育系统、传粉综合征与扩散综合征是解析热带干旱林修复过程的关键核心要素。本研究针对哥斯达黎加瓜纳卡斯特地区的3个热带干旱林演替阶段（早期、中期与晚期），对其树木物种组成与多样性展开描述与对比分析。此外，本研究首次针对中美洲规模最大、生态意义最显著的热带干旱林残存群落，系统刻画了其树木物种的繁育系统、传粉综合征与扩散综合征。本研究共设置9块样地，每个演替阶段布设3块，总计调查并鉴定了隶属于96个物种的1072株树木。研究结果显示，中期演替阶段的物种丰富度与多样性指数均为最高。与其他热带生物带的研究结果一致，雌雄同株是该区域最常见的树木繁育系统。昆虫为主要传粉媒介，这一现象得益于树木所具有的小型花序结构。风不仅是第二大主导传粉媒介（主要分布于开阔且受干扰的早期演替森林），同时也是一种高效的种子扩散媒介。随着热带干旱林林龄的增加，鸟类与哺乳动物作为种子扩散者的重要性显著提升，因此晚期演替阶段中适配这类扩散者的树木物种占比更高。