SGER: Ecophysiological Consequences of Infrequent Massive Flowering of Monocarpic Bamboo Grasses (Chusquea spp.) in Temperate and Tropical South America

竹草是亚洲和美洲亚热带和温带森林林下植被的重要组成部分，在许多情况下，竹草完全占森林低层的主导地位。这些竹草具有重要的经济和保护价值，因为它们在整个森林生态系统的功能中发挥着关键作用，并为众多当地人口提供食物和住所。大多数物种在它们的生命周期中只开一次花，可以持续长达120年，然后就会死亡。当竹草开花时，开花是高度同步的，因此有大量的“波”开花和草的立即死亡，同时影响大片的森林植被。这些不频繁和短暂的事件在许多方面对受影响森林中的动植物产生影响，但由于这些事件非常罕见，人们对森林再生和维持本地生物多样性的后果知之甚少。2001年底，南美洲南部的森林开始经历竹草的大规模开花，发生在北纬25至45度的广阔地区，包括亚热带森林和温带森林。这是一个探索这种大规模和罕见现象对维持本地生物多样性和森林再生的重要性以及对这些森林中碳和氮储量的影响的机会。计划在南美洲沿纬度梯度发生大规模开花的几个地区进行观察，目的是确定这种现象如何导致水、光和营养资源的可用性变化，以及这些变化如何影响本地物种的再生、开花和生理。不同变量的同时变化和潜在的对比效应使我们很难完全理解竹子开花的后果。在田间试验中，我们将操纵光和养分的可用性，这将使我们能够解开由这一重大而罕见的事件造成的不同机制。更好地了解竹子这种罕见开花的机制和后果，以及它对本地植物过程的影响，有助于我们做出明智的决定，以维护世界各地本地生态系统中的本地动植物生命。

Bamboo grasses are an important component of understory vegetation in subtropical and temperate forests in both Asia and the Americas and in many cases they completely dominate the lower layers of the forest. These bamboo grasses have important economic and conservation value since they play a key role in the functioning of the entire forest ecosystem and provide food and shelter to numerous native populations. Most species flower only once in their life cycle, which can last up to 120 years, and then die. When bamboo grasses flower, the flowering is highly synchronous, such that there are massive 'waves' of flowering and immediate death of the grasses, affecting large patches of forest vegetation simultaneously. These infrequent and ephemeral events have consequences in many ways for both plants and animals in the affected forests, but because these events are so rare, little is known of the consequences on forest regeneration and maintenance of native biodiversity. In late 2001, forests in southern South America started to experience massive flowering of the bamboo grasses occurring over a vast area ranging in latitude from 25 to 45 degrees S, in both subtropical forests and temperate forests. This is an opportunity to explore the importance of this large-scale and infrequent phenomenon on the maintenance of native biodiversity and forest regeneration, as well as effects on carbon and nitrogen stocks in these forests. Observations are planned in several areas along a latitudinal gradient in South America where massive flowering is occurring, with the aim of identifying how resource availability of water, light and nutrients change as a result of this phenomenon and how these changes influence the regeneration, flowering, and physiology of native species. The simultaneous change of different variables with potentially contrasting effects make it difficult to fully understand the consequences of bamboo flowering. A field experiment, where we will manipulate light and nutrient availability, will allow us to disentangle the different mechanisms resulting from this major and infrequent event. A greater understanding of the mechanisms and consequences of this infrequent flowering in bamboo and its effect on native plant processes can contribute to our ability to make informed decisions for the maintenance of native plants and animal life in native ecosystems around the world.