Resolving the current and future carbon dynamics of the dry tropics

解决干燥热带地区当前和未来的碳动态

• 批准号: NE/T012722/1
• 负责人: Oliver Phillips
• 金额: $ 69.95万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FT012722%2F1
• 关键词: Resolving; current; future; carbon; dynamics

The ecosystems of the dry tropics are in flux: the savannas, woodlands and dry forests that together cover a greater area of the globe than rainforests are both a source of carbon emissions due to deforestation and forest degradation, and also a sink due to the enhanced growth of trees. However, both of these processes are poorly understood, in terms of their magnitude and causes, and the net carbon balance and its future remain unclear. This gap in knowledge arises because we do not have a systematic network of observations of vegetation change in the dry tropics, and thus have not, until now, been able to use observations of how things are changing to understand the processes involved and to test key theories.Satellite remote sensing, combined with ground measurements, offers the ideal way to overcome these challenges, as it can provide regular, consistent monitoring at relatively low cost. However, most ecosystems in the dry tropics, especially savannas, comprise a mixture of grass and trees, and many optical remote sensing approaches (akin to enhanced versions of the sensors on digital cameras) struggle to distinguish changes between the two. Long wavelength radar remote sensing avoids this problem as it is insensitive to the presence of leaves or grass, and also is not affected by clouds, smoke or the angle of the sun, all of which complicate optical remote sensing. Radar remote sensing is therefore ideal to monitor tree biomass in the dry tropics. We have successfully demonstrated that such data can be used to accurately map woody biomass change for all 5 million sq km of southern Africa.In SECO we will create a network of over 600 field plots to understand how the vegetation of the dry tropics is changing. and complement this with radar remote sensing to quantify how the carbon cycle of the dry tropics has changed over the last 15 years. This will provide the first estimates of key carbon fluxes across all of the dry tropics, including the amount of carbon being released by forest degradation and deforestation and how much carbon is being taken up by the intact vegetation in the region. By understanding where these processes are happening, we will improve our knowledge of the processes involved. W will use these new data to improve the way we model the carbon cycle of the dry tropics, and test key theories. The improved understanding, formalised into a model, will be used to examine how the dry tropics will respond to climate change, land use change and the effects of increasing atmospheric CO2. We will then be able to understand whether the vegetation of the dry tropics will mitigate or exacerbate climate change, and we will learn what we need to do to maintain the structure of the dry tropics and preserve its biodiversity. Overall, SECO will allow us to understand how the vegetation of the dry tropics is changing, and the implications of this for the global carbon cycle, the ecology of savannas and dry forests, and efforts to reduce climate change. The data we create, and the analyses we conduct will be useful to other researchers developing methods to monitor vegetation from satellites, and also to those who model the response of different ecosystems to climate and other changes. Forest managers, ecologists and development practitioners can use the data to understand which parts of the world's savannas and dry forests are changing most, and how these changes might be managed to avoid negative impacts that threaten biodiversity and the livelihoods of the 1 billion, mostly poor, rural people who live in this region.

干燥热带地区的生态系统处于不断变化之中：热带稀树草原、林地和干燥森林加起来比热带雨林覆盖的全球面积更大，它们既是由于砍伐森林和森林退化造成的碳排放源，也是由于树木生长加快造成的碳汇。然而，就其规模和原因而言，人们对这两个过程知之甚少，净碳平衡及其未来仍不清楚。这种知识上的差距之所以出现，是因为我们没有一个系统的网络来观察干旱热带地区的植被变化，因此，直到现在，我们还不能通过观察事物的变化来理解所涉及的过程，并检验关键理论。卫星遥感与地面测量相结合，提供了克服这些挑战的理想方法，因为它可以以相对较低的成本提供定期、一致的监测。然而，干燥热带地区的大多数生态系统，特别是热带稀树草原，由草和树混合组成，许多光学遥感方法（类似于数码相机传感器的增强版本）难以区分两者之间的变化。长波雷达遥感避免了这个问题，因为它对树叶或草的存在不敏感，也不受云、烟或太阳角度的影响，所有这些都使光学遥感复杂化。因此，雷达遥感是监测干燥热带地区树木生物量的理想方法。我们已经成功地证明，这些数据可以用来准确地绘制非洲南部所有500万平方公里的木质生物量变化图。在SECO，我们将创建一个由600多个地块组成的网络，以了解干燥热带地区的植被是如何变化的。并辅以雷达遥感来量化过去15年来干燥热带地区的碳循环是如何变化的。这将提供对所有干燥热带地区关键碳通量的首次估计，包括森林退化和森林砍伐释放的碳量，以及该地区完整植被吸收的碳量。通过了解这些过程发生的位置，我们将提高我们对相关过程的认识。我们将利用这些新数据来改进我们模拟干旱热带地区碳循环的方法，并检验关键理论。这一改进后的认识将形成一个模型，用于研究干燥的热带地区将如何对气候变化、土地利用变化和大气中二氧化碳增加的影响作出反应。这样我们就能了解干旱热带地区的植被是否会减缓或加剧气候变化，我们也会知道我们需要做些什么来维持干旱热带地区的结构和保护其生物多样性。总的来说，SECO将使我们了解干旱热带地区的植被是如何变化的，以及这种变化对全球碳循环、热带稀树草原和干旱森林生态的影响，以及减少气候变化的努力。我们创建的数据和我们进行的分析将对其他研究人员开发从卫星监测植被的方法有用，也对那些模拟不同生态系统对气候和其他变化的反应的研究人员有用。森林管理者、生态学家和发展实践者可以利用这些数据来了解世界上哪些地区的稀树草原和干旱森林变化最大，以及如何管理这些变化，以避免威胁生物多样性和生活在该地区的10亿农村人口（主要是贫困人口）生计的负面影响。

项目成果

Intra-annual stable isotopes in the tree rings of Hymenaea courbaril as a proxy for hydroclimate variations in southern Amazonia

• DOI: 10.1016/j.dendro.2023.126151
• 发表时间: 2023-12
• 期刊: Dendrochronologia
• 影响因子: 3
• 作者: Karollyne Silva Guimarães;B. Marimon;G. M. Locosselli;R. Brienen;B. B. Cintra-B.;Arnoud Boom;Igor Araújo;B. H. Marimon‐Junior;G. Ceccantini;W. J. A. da Cruz;Oliver L. Phillips

Taking the pulse of Earth's tropical forests using networks of highly distributed plots

• DOI: 10.1016/j.biocon.2020.108849
• 发表时间: 2021-07-27
• 期刊: BIOLOGICAL CONSERVATION
• 影响因子: 5.9
• 作者: Blundo, Cecilia;Carilla, Julieta;Tran, Hieu Dang
• 通讯作者: Tran, Hieu Dang

Spatial distribution of aboveground biomass stock in tropical dry forest in Brazil

巴西热带干旱森林地上生物量储量的空间分布

• DOI: 10.3832/ifor4104-016
• 发表时间: 2023
• 期刊: iForest - Biogeosciences and Forestry
• 作者: Viana Santos H

Sensing Forests Directly: The Power of Permanent Plots.

直接感知森林：永久地块的力量。

• DOI: 10.3390/plants12213710
• 发表时间: 2023-10-28
• 期刊: Plants (Basel, Switzerland)
• 作者: Phillips OL

Mapping wood volume in seasonally dry vegetation of Caatinga in Bahia State, Brazil

• DOI: 10.1590/1678-992x-2022-0161
• 发表时间: 2023-04
• 期刊: Scientia Agricola
• 影响因子: 2.6
• 作者: Thaine Teixeira Silva;R. B. Lima;R. L. M. D. Souza;P. Moonlight;D. Cardoso;Héveli Kalini Viana Santos;C. P. Oliveira;E. Veenendaal;L. P. Queiroz;P. M. S. Rodrigues;R. M. Santos;T. Sarkinen;A. Paula;P. Barreto-Garcia;T. Pennington;O. Phillips