Linking life-history trade-offs to population genetic structure in tropical forest trees: implications for maintenance of species richness

将生活史权衡与热带森林树木种群遗传结构联系起来：对维持物种丰富度的影响

基本信息

批准号：
NE/D003822/1
负责人：
David Francis Robert Philip Burslem
金额：
$ 37.79万
依托单位：
University of Aberdeen
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2006
资助国家：
英国
起止时间：
2006 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FD003822%2F1
关键词：
Linking life history trade offs

项目摘要

The tropical forests of Borneo are dominated by more than 250 tree species in one family, the Dipterocarpaceae, many of which have a similar form, architecture and ecology. Because of these similarities among species, it is uncertain what prevents a small number of species from dominating the forest and driving other species to extinction. One possibility is that differences in fruit production between species are minimized by biotic interactions that we don't yet understand. For example, we have found that the dipterocarp species at one site adopt different flowering strategies: species with small flowers tend to produce many of them, and vice versa. This 'trade-off' could equalize the average number of offspring produced by different species, and thereby prevent a small number of species from dominating the forest, but this interpretation requires us to invoke a differential likelihood that small and large flowers will develop into fruits and established seedlings. We will investigate how flower size compensates for flower number to equalize fruit production among species. We will focus on two potential costs for small flowers: (a) the reduced likelihood that a small flower will be pollinated, as the trees that produce small flowers tend to produce many more of them and pollinators are a scare resource, and (b) the increased chance that small flowers will receive pollen from a genetically-related near neighbour, leading to an increased potential for inbreeding to reduce the viability of offspring. Our guiding hypothesis is that competition for insect pollinators during flowering underlies the evolution of flowering strategy, which is credible because dipterocarp trees tend to flower synchronously at irregular intervals during intense 'general flowering' (GF) events separated by periods of 4-7 years. During GF events most large trees in the forest flower simultaneously over a 4-6 wk period, and during this time the demand for pollinators suddenly increases. Dipterocarps are pollinated by insects that vary in size from tiny flower thrips (< 1 mm in length) to very large giant honey bees (45 mm in length), and the average size of pollinator increases with flower size. The mobility of these insect pollinators is important, because their foraging determines the movement of genetic material from the father to the mother tree. We know that thrips can only fly very short distances, whereas giant honey bees can travel a few tens of km in search of food, and we will find out whether these differences in mobility translate into differences in the average distance that pollen gets transported between flowering trees. Furthermore, because dipterocarps are large-seeded and poorly dispersed, the movement of genes within a population is likely to be more strongly associated with dispersal of pollen than fruits. Therefore we predict that neighbouring individuals of species pollinated by small relatively immobile insects will be more closely related to each other than neighbouring individuals of species pollinated by large, mobile insects. We will check for evidence of inbreeding depression by hand pollinating the flowers of mother trees with pollen collected from fathers at different distances away from the mother and assessing effects on fruit development and seedling performance. This project will establish whether flower size and flower number are linked to pollinator size and mobility, the dispersal of pollen and the clustering of genetically related individuals in the forest. It offers an exciting new way of thinking about how diversity is maintained in an important tropical forest community and has general applicability to any plant community where competition for pollinators might underlie the evolution of flowering strategies. The work also has relevance to the management of disturbed and fragmented tropical forest communities where plant-pollinator interactions are disrupted by changes in mean distance between flowering trees.

婆罗洲的热带森林以龙脑香科 250 多种树种为主，其中许多树种具有相似的形态、结构和生态。由于物种之间的这些相似性，尚不清楚是什么阻止了少数物种统治森林并导致其他物种灭绝。一种可能性是，物种之间水果产量的差异通过我们尚不了解的生物相互作用而被最小化。例如，我们发现同一地点的龙脑香属植物物种采用不同的开花策略：花朵较小的物种往往会产生很多花朵，反之亦然。这种“权衡”可以使不同物种产生的后代的平均数量相等，从而防止少数物种主宰森林，但这种解释要求我们援引小花和大花发育成果实的不同可能性并建立了幼苗。我们将研究花的大小如何补偿花的数量，以平衡物种之间的果实产量。我们将重点关注小花的两个潜在成本：（a）小花授粉的可能性降低，因为产生小花的树木往往会产生更多的小花，而传粉媒介是一种稀缺资源，以及（b）小花从有遗传关系的近邻那里获得花粉的机会增加，导致近亲繁殖的可能性增加，从而降低后代的生存能力。我们的指导性假设是，开花期间对昆虫传粉者的竞争是开花策略进化的基础，这是可信的，因为龙脑香树往往在密集的“一般开花”（GF）事件期间以不规则的间隔同步开花，间隔时间为 4-7 年。在 GF 事件期间，森林中的大多数大树在 4-6 周内同时开花，在此期间对传粉媒介的需求突然增加。龙脑香科植物通过大小不等的昆虫授粉，从微小的花蓟马（长度 < 1 毫米）到非常大的巨型蜜蜂（长度 45 毫米），传粉昆虫的平均尺寸随着花的大小而增加。这些昆虫传粉媒介的流动性很重要，因为它们的觅食决定了遗传物质从父树到母树的移动。我们知道蓟马只能飞行很短的距离，而巨型蜜蜂可以飞行几十公里来寻找食物，我们将找出这些移动性的差异是否会转化为花粉在开花之间运输的平均距离的差异树。此外，由于龙脑香科植物种子大且分散性差，群体内基因的移动可能与花粉传播的相关性比果实的相关性更强。因此，我们预测，由相对固定的小型昆虫授粉的物种的相邻个体之间的关系将比由大型移动昆虫授粉的物种的相邻个体之间的关系更密切。我们将通过从距母树不同距离的父树上收集的花粉对母树的花朵进行人工授粉，并评估对果实发育和幼苗表现的影响，来检查近交衰退的证据。该项目将确定花的大小和花的数量是否与传粉媒介的大小和流动性、花粉的传播以及森林中遗传相关个体的聚集有关。它提供了一种令人兴奋的新方式来思考如何在重要的热带森林群落中保持多样性，并且普遍适用于传粉者竞争可能成为开花策略演变基础的任何植物群落。这项工作还与受干扰和支离破碎的热带森林群落的管理有关，在这些群落中，植物与传粉者的相互作用因开花树木之间的平均距离的变化而受到干扰。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Ecological implications of a flower size/number trade-off in tropical forest trees.

热带森林树木花朵大小/数量权衡的生态影响。

DOI：
10.1371/journal.pone.0016111
发表时间：
2011
期刊：
PloS one
影响因子：
3.7
作者：
Kettle CJ
通讯作者：
Kettle CJ

Ecological Implications of a Flower Size/Number Trade-Off in Tropical Forest Trees

热带森林树木花大小/数量权衡的生态意义

DOI：
10.3929/ethz-b-000031447
发表时间：
2011
期刊：
影响因子：
0
作者：
Kettle, Chris J.
通讯作者：
Kettle, Chris J.

Seeing the fruit for the trees in Borneo Seeing the fruit for the trees in Borneo

看到婆罗洲树木结出的果实看到婆罗洲树木结出的果实

DOI：
10.1111/j.1755-263x.2010.00161.x
发表时间：
2011
期刊：
Conservation Letters
影响因子：
8.5
作者：
Kettle C
通讯作者：
Kettle C

Topography shapes the structure, composition and function of tropical forest landscapes.

DOI：
10.1111/ele.12964
发表时间：
2018-07
期刊：
Ecology letters
影响因子：
8.8
作者：
Jucker T;Bongalov B;Burslem DFRP;Nilus R;Dalponte M;Lewis SL;Phillips OL;Qie L;Coomes DA
通讯作者：
Coomes DA

Impacts of an Extreme Precipitation Event on Dipterocarp Mortality and Habitat Filtering in a Bornean Tropical Rain Forest

婆罗洲热带雨林极端降水事件对龙脑香死亡率和栖息地过滤的影响