In stressful environments, a nurse plant can ameliorate harsh biotic and abiotic conditions for another plant species that grows within its canopy. This canopy can act as a barrier for herbivores, reducing damage to the protected plants inside, but it can also reduce access to pollinators possibly resulting in a tradeoff between survival and reproductive output. In a semi‐arid ecosystem, the shrub Porlieria chilensis acts as a nurse, increasing soil moisture, nutrients and reducing temperature inside its canopy compared to open areas. Flourensia thurifera is one of the beneficiary shrubs that can grow inside P. chilensis, where it shows increased survival and performance compared to open areas. However, growing inside P. chilensis’ canopy may reduce pollinator visit. We aim to evaluate the possible tradeoff between survival and reproduction in F. thurifera individuals growing inside and outside the canopy of P. chilensis. This was achieved through a field experiment were we measured survival, pollinator visits and seed output of F. thurifera plants growing inside and outside the canopy of P. chilensis. Flourensia thurifera individuals had a higher survival when growing within the canopy of P. chilensis and had lower pollinator visits and seed output compared to plants growing in open areas. Thus, we found a significant negative correlation between plant survival and seed output considering both conditions (inside or outside nurses), evidencing a tradeoff between these traits. The tradeoff evidenced here could have large impact at the population and community level. On one hand, this tradeoff could mask possible nurse effects in other species, since they could show a similar net fitness in both microhabitat (inside or outside nurses). Finally, we propose a theoretical model to assess the change in the shape of this tradeoff under future climatic conditions where temperature and precipitation are predicted to vary due to climate change.

中文翻译：

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在半干旱生态系统中，与健身相关的特征之间的权衡掩盖了促进作用

在压力环境中，护士植物可以改善其冠层中生长的另一种植物的恶劣生物和非生物条件。该冠层可以作为草食动物的屏障，减少对内部受保护植物的损害，但也可以减少对传粉媒介的利用，可能导致生存与繁殖产量之间的权衡。在半干旱的生态系统中，灌木Porlieria chilensis充当护士，与空旷地区相比，增加了土壤水分，养分并降低了冠层内部的温度。苏打金（Flourensia thurifera）是可以在智利假单胞菌内部生长的有益灌木之一，与空旷地区相比，它显示出更高的存活率和性能。然而，生长在智利假单胞菌内部冠层可以减少传粉者的来访。我们的目标是评估的生存和繁殖之间的权衡可能F. thurifera个人日益增长的内部和外部的树冠P. chilensis的。这是通过一个田间试验取得了我们测量存活，授粉访问和种子输出F. thurifera植物生长内外的篷P. chilensis的。当在P. chilensis的冠层内生长时，Flourensia thurifera个体的存活率更高。与在空旷地区种植的植物相比，传粉者访视和种子产量更低。因此，我们发现在两种条件下（内部或外部护士），植物存活率与种子产量之间均存在显着的负相关，证明了这些性状之间的权衡。此处证明的权衡可能会对人口和社区层面产生重大影响。一方面，这种权衡可能掩盖了其他物种中可能的护士效应，因为它们在两个微生境中（内部或外部护士）都显示出相似的净适应度。最后，我们提出了一个理论模型来评估在未来气候条件下这种权衡形状的变化，在未来气候条件下，温度和降水预计会因气候变化而变化。