Understanding interactions between species in altered ecosystems is important, as they influence resilience and opportunities for restoration. Here we explore a multipartite interaction between an important early succession myrmecophytic tree in Borneo (Macaranga pearsonii), and its ant mutualists that provide protection from herbivores. We compare the mutualistic system between two highly degraded habitats that are candidates for future restoration: oil palm plantation and recently heavily-logged forest. For each tree we measured tree structure (height, diameter, number of branches), leaf biomass and herbivore damage. We also measured soil characteristics (phosphate and nitrate content, pH, density) and canopy openness as these may influence tree health. For each branch, we quantified number of ant workers, brood, alates and queens as well as number of coccids. The ants tend these symbiotic coccids for their sugar-rich exudate produced by sucking the tree’s sap. We demonstrate that herbivore damage was up to twice as high in oil palm plantation compared to heavily-logged forest. This herbivory increase was not related directly to changes in abiotic conditions or to higher herbivore pressure, but rather to the distribution of the ant workers within the trees. However, trees in oil palm were able to compensate for the increased herbivory by increasing leaf production. For similar ant abundance, fewer branches were occupied in oil palm plantation, and there were relatively more ants in the presence of coccids. Taken together, our findings indicate that although this mutualism has variation in its functioning, with reduced benefits for the tree of ant occupation in oil palm plantation, the mutualism persists in oil palm. Therefore Macaranga pearsonii is a viable candidate for forest restoration (just as in secondary forest) if these trees are allowed to grow in oil palm plantations.

中文翻译：

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与高砍伐的森林相比，油棕中的蚂蚁树减少了蚂蚁占领的收益

了解变化的生态系统中物种之间的相互作用非常重要，因为它们会影响复原力和恢复机会。在这里，我们探索婆罗洲（Macaranga pearsonii）的重要早期演替继发性肉生树之间的多部分相互作用。）及其蚂蚁互助主义者提供食草动物的保护。我们比较了两个高度退化的生境之间的互惠系统，这些生境是未来恢复的候选对象：油棕种植园和最近茂密的森林。对于每棵树，我们测量了树的结构（高度，直径，分支数），叶片生物量和草食动物的损害。我们还测量了土壤特性（磷酸盐和硝酸盐含量，pH，密度）和冠层开放度，因为它们可能会影响树木的健康。对于每个分支，我们量化了蚂蚁工人，育雏，板栗和蚁后的数量以及球虫的数量。蚂蚁倾向于这些共生的球虫，因为它们通过吮吸树液产生了富含糖分的分泌物。我们证明，与茂密砍伐的森林相比，油棕种植中的草食动物损害高达两倍。草食动物的增加与非生物条件的变化或草食动物压力的升高没有直接关系，而是与蚂蚁工人在树上的分布没有直接关系。但是，油棕中的树木能够通过增加叶片产量来补偿食草动物的增加。对于类似的蚂蚁丰度，油棕种植园中占据的分支较少，而存在球虫的蚂蚁相对较多。两者合计，我们的研究结果表明，尽管这种共生关系在功能上有所不同，但油棕种植园中蚂蚁占领树的收益减少，但共生关系在油棕中仍然存在。因此 油棕中的树木能够通过增加叶片产量来补偿食草动物的增加。对于类似的蚂蚁丰度，油棕种植园中占据的分支较少，而存在球虫的蚂蚁相对较多。两者合计，我们的研究结果表明，尽管这种共生关系在功能上有所不同，但油棕种植园中蚂蚁占领树的收益减少，但共生关系在油棕中仍然存在。因此 油棕中的树木能够通过增加叶片产量来补偿食草动物的增加。对于类似的蚂蚁丰度，油棕种植园中占据的分支较少，而存在球虫的蚂蚁相对较多。两者合计，我们的研究结果表明，尽管这种共生关系在功能上有所不同，但油棕种植园中蚂蚁占领树的收益减少，但共生关系在油棕中仍然存在。因此 互助共存于油棕之中。因此 互助共存于油棕之中。因此如果允许这些树木在油棕人工林中生长，则Macaranga pearsonii可以作为森林恢复的可行候选人（就像在次生森林中一样）。