Fronds to forests: Individual-based and whole-forest models of kelp

在一些国家，特别是远东地区，收获用于生物燃料、肥料、提取用于人类和动物食品和药品的化学物质的海藻是一个重要的产业。在东北大西洋地区，只有在法国和挪威才有专门船只进行大规模捕捞。挪威每年收获超过10万吨。据估计，苏格兰水域的海带（主要是海带）的生物量超过2000万吨，20世纪70年代至90年代，西部群岛发展了每年10,000-15,000吨的海带采收产业。然而，目前的采收仅限于少数生产特殊产品的手工采收企业，最近关于机械采收的建议已被苏格兰政府拒绝，等待彻底审查。在苏格兰，反对机械采收海带的动机似乎更多地是出于预防措施，而不是基于大规模不利后果的任何具体科学证据，至少从设想的采收规模来看是如此。事实上，尽管从法国和挪威的经验中获得了关于有效采伐策略的丰富的基于经验的知识，但对海带森林动态的科学理解明显缺乏。海带是一种寿命相对较长的（根据物种的不同可达10年）生理复杂的植物，能够储存大量的氮储备，并向环境中排泄大量的多糖。森林为各种无脊椎动物和脊椎动物提供了密集的栖息地，森林的动态取决于一系列环境因素，如浊度、温度和波浪暴露，以及密度依赖的调节过程，如代际空间竞争（沉淀孢子需要一个安全的表面来保持生长）和自遮阳竞争。这些依赖于密度的过程恰恰是可能减轻或加剧采伐对森林的任何影响的过程。在这个项目中，我们将开发适合苏格兰水域的海带森林动态的数学模型，然后可以用来探索自然变化和采伐对森林生物量和再生的影响。我们将从两个方向来解决这个问题——使用整个森林生物量和特性的模型，以及基于个体的相互作用植物的模型。文献中存在的几种海带动力学模型3,4通常模拟单个植物的发育（生长和生存），然后假设这与森林发展是同义词。然而，事实并非如此。博士项目的任务将是：开发、测试和参数化森林和基于个体的模型，用于苏格兰周围的一系列井研究地点，从克雷兰湖的历史数据遗产开始。-进行模型实验，以确定在何种程度上，以及在何种条件和参数值下，整个森林模型能够模拟基于个体的模型的行为。-使用模型进行实验，以确定最佳采伐策略，以确保未来森林生物量和结构的可持续发展1 capuzzo， E. and McKie， T.（2016）。海藻在英国和国外的现状，产品，限制，差距和Cefas的作用。Cefas合同报告FC002I78页。2Burrows等人（2018）野生海藻收获是渔民多样化的机会。由SRSL为HIE撰写的报告，第1713页aldridge， J., van de Molen， J.和Forster， R.（2012）。大型藻类种植的更广泛的生态影响。《皇家财产》，95页。broch， oj和Slagstad， D.（2012）。模拟海带Saccharina latissimi的季节性生长和组成。j:。庄士敦，c.s.，琼斯，R.G.和亨特，R.D.（1977）。苏格兰海湖海带动物种群的季节性碳预算。Helgolander威斯康星州。

Harvesting of seaweeds for biofuel, fertiliser, and extraction of chemicals for human and animal food products, and pharmaceuticals, is a significant industry in some countries especially the Far East1. In the northeast Atlantic region, significant harvesting involving dedicated vessels occurs only in France and Norway. The annual Norwegian harvest is more than 100,000 tonnes. The biomass of kelp (mainly Laminaria hyperborea) in Scottish waters is estimated to be in excess of 20 million tonnes2, and a 10,000-15,000 tonne per annum harvesting industry developed in the Western Isles during the 1970's-1990's. However, the current harvesting is confined to a small number of hand-harvesting businesses producing speciality products, and recent proposals for mechanical harvesting have been rejected by the Scottish Government pending a thorough review. Opposition to mechanical harvesting of kelp at sites in Scotland appears to be motivated more by a precautionary approach, and not based on any specific scientific evidence of large scale adverse consequences, at least from the scale of harvesting that is envisaged. In fact, although there is ample experience-based knowledge on effective harvesting strategies from French and Norwegian experiences, scientific understanding of kelp forest dynamics is markedly lacking. Kelp are relatively long-lived (up to 10 years depending on species) physiologically complex plants, able to store significant reserves of nitrogen, and excrete quantities of polysaccharides into the environment. Forests provide a dense habitat for a wide range of invertebrate and vertebrate species, and forest dynamics depend on a range of environmental factors such as turbidity, temperature and wave exposure, and density-dependent regulatory process such as inter-generational competition for space (settling spores require a secure surface for holdfast development), and self-shading competition for light. These density dependent processes are exactly the ones that may mitigate or accentuate any effects of harvesting on the forests.In this project we will develop mathematical models of kelp forest dynamics appropriate to Scottish waters that can then be used to explore the consequences of natural variability and harvesting on forest biomass and regeneration. We will approach the problem from two directions - using models of whole-forest biomass and properties, and individual-based models of interacting plants. The few models of kelp dynamics that exist in the literature3,4 generally model the development (growth and survival ) of individual plants, and then assume that this is synonymous with forest development. However, this is not necessarily the case.The task of the PhD project will be to:-Develop, test and parameterise both the forest and individual-based models for a range of well studies sites around Scotland, starting with the legacy of historical data from Loch Creran5.-Conduct model experiments to determine the extent, and under what conditions and parameter values, the whole-forest model is able to simulate the behaviour of the individual-based models.-Conduct experiments with the models to determine the optimum harvesting strategy to ensure sustainable forest biomass and structure into the future1Capuzzo, E. and McKie, T. (2016). Seaweed in the UK and abroad - status, products, limitations, gaps and Cefas role. Cefas contract report FC002I. 78pp.2Burrows et al. (2018) Wild Seaweed Harvesting as a Diversification Opportunity for Fishermen. A report by SRSL for HIE, pp. 1713Aldridge, J., van de Molen, J. and Forster, R. (2012). Wider ecological implications of Macroalgae cultivation. The Crown Estate, 95 pp.4Broch, O.J. and Slagstad, D. (2012). Modelling seasonal growth and composition of the kelp Saccharina latissimi. J. Appl. Phycol. 24, 759-776.5Johnston, C.S., Jones, R.G. and Hunt, R.D. (1977). A seasonal carbon budget for a laminarian population in a Scottish sea-loch. Helgolander Wiss.