Abstract Forest loss and fragmentation threaten the high diversity of tropical forests. Tropical epiphytes are a key component of plant diversity and significant for ecosystem functioning, and they are vulnerable to these forces. We explored the potential of shade trees in agroforestry systems to sustain and restore epiphyte communities where forest cover has been lost. We investigated epiphyte colonization patterns using surveys of 748 trees within 87 variously-aged plots in coffee agroecosystems in northern Nicaragua. Species richness increased with stand age, reflecting effects of area, time, and the niche differentiation possible within larger trees. Young trees near mature trees were almost five times more likely to support epiphytes than those surrounded by other young trees, suggesting that propagule sources severely limit colonization in young, even-aged stands. We identified three stages of epiphyte colonization: an initial stage where trees lack epiphytes; a colonization stage where epiphyte abundance increases slowly; and a mature stage where accumulation accelerates as trees become large enough to support distinct microhabitats. Atmospheric bromeliads and several fern species with traits that facilitate dispersal, colonization, and persistence under open, sunny environmental conditions colonized young trees first. Thus, both environmental filtering and dispersal limitation drive community assembly in these agroforests. Because epiphytes colonize gradually, consistent land tenure and long-term management allow time for newly planted trees in shade coffee farms to develop to the size and structural complexity needed to support diverse epiphyte communities. Because ideal conditions for epiphytes may be at odds with managing for maximum coffee yields and some epiphyte species may never colonize coffee farms, even mature shade trees in coffee plantations cannot replace protecting native forests.

中文翻译：

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树木长寿推动了荫蔽咖啡农场对维管附生植物的保护价值

摘要 森林丧失和破碎威胁着热带森林的高度多样性。热带附生植物是植物多样性的关键组成部分，对生态系统功能具有重要意义，它们容易受到这些力量的影响。我们探索了农林业系统中遮荫树在森林覆盖消失的地方维持和恢复附生植物群落的潜力。我们使用对尼加拉瓜北部咖啡农业生态系统中 87 个不同年龄地块中的 748 棵树的调查来调查附生植物的定植模式。物种丰富度随林龄而增加，反映了面积、时间和较大树木内可能的生态位分化的影响。靠近成熟树木的幼树比被其他幼树包围的幼树支持附生植物的可能性几乎是其五倍，表明繁殖源严重限制了年轻、偶龄林群的定植。我们确定了附生植物定植的三个阶段：树木缺乏附生植物的初始阶段；附生植物丰度缓慢增加的定植阶段；成熟阶段，随着树木变得足够大以支持不同的微生境，积累加速。大气凤梨科植物和几种蕨类植物在开放、阳光充足的环境条件下具有促进扩散、定植和持久性的特征，首先定植幼树。因此，环境过滤和扩散限制都推动了这些农林中的群落组装。由于附生植物逐渐定殖，一致的土地使用权和长期管理为遮荫咖啡农场新种植的树木留出时间，使其达到支持不同附生植物群落所需的规模和结构复杂性。由于附生植物的理想条件可能与管理最大咖啡产量不一致，并且一些附生植物物种可能永远不会在咖啡农场定殖，因此即使是咖啡种植园中成熟的遮荫树也不能取代保护原生森林。