Pfeifer Marion, Boyle Michael J W, Dunning Stuart, Olivier Pieter I
Modelling, Evidence & Policy Group, SNES, Newcastle University, Newcastle Upon Tyne, United Kingdom.
Forest Ecology and Conservation Group, Silwood Park Campus, Imperial College London, Ascot, Berkshire, United Kingdom.
PeerJ. 2019 Jan 10;7:e6190. doi: 10.7717/peerj.6190. eCollection 2019.
Tropical landscapes are changing rapidly due to changes in land use and land management. Being able to predict and monitor land use change impacts on species for conservation or food security concerns requires the use of habitat quality metrics, that are consistent, can be mapped using above-ground sensor data and are relevant for species performance. Here, we focus on ground surface temperature ( ) and ground vegetation greenness ( ) as potentially suitable metrics of habitat quality. Both have been linked to species demography and community structure in the literature. We test whether they can be measured consistently from the ground and whether they can be up-scaled indirectly using canopy structure maps (Leaf Area Index, , and Fractional vegetation cover, ) developed from Landsat remote sensing data. We measured and across habitats differing in tree cover (natural grassland to forest edges to forests and tree plantations) in the human-modified coastal forested landscapes of Kwa-Zulua Natal, South Africa. We show that both metrics decline significantly with increasing canopy closure and leaf area, implying a potential pathway for upscaling both metrics using canopy structure maps derived using earth observation. Specifically, our findings suggest that opening forest canopies by 20% or decreasing forest canopy by one unit would result in increases of by 1.2 °C across the range of observations studied. appears to decline by 0.1 in response to an increase in canopy by 1 unit and declines nonlinearly with canopy closure. Accounting for micro-scale variation in temperature and resources is seen as essential to improve biodiversity impact predictions. Our study suggests that mapping ground surface temperature and ground vegetation greenness utilising remotely sensed canopy cover maps could provide a useful tool for mapping habitat quality metrics that matter to species. However, this approach will be constrained by the predictive capacity of models used to map field-derived forest canopy attributes. Furthermore, sampling efforts are needed to capture spatial and temporal variation in within and across days and seasons to validate the transferability of our findings. Finally, whilst our approach shows that surface temperature and ground vegetation greenness might be suitable habitat quality metric used in biodiversity monitoring, the next step requires that we map demographic traits of species of different threat status onto maps of these metrics in landscapes differing in disturbance and management histories. The derived understanding could then be exploited for targeted landscape restoration that benefits biodiversity conservation at the landscape scale.
由于土地利用和土地管理的变化,热带景观正在迅速改变。为了出于保护或粮食安全考虑预测和监测土地利用变化对物种的影响,需要使用一致的、能够利用地面传感器数据进行绘制且与物种表现相关的栖息地质量指标。在此,我们重点关注地表温度( )和地面植被绿度( )作为潜在合适的栖息地质量指标。在文献中,这两者都与物种种群统计学和群落结构相关联。我们测试它们是否能从地面进行一致测量,以及是否能使用从陆地卫星遥感数据生成的冠层结构地图(叶面积指数, ,和植被覆盖度, )进行间接尺度扩展。我们在南非夸祖鲁 - 纳塔尔人类改造的沿海森林景观中,对不同树木覆盖程度(从天然草地到森林边缘再到森林和人工林)的栖息地测量了 和 。我们表明,随着冠层郁闭度和叶面积增加,这两个指标均显著下降,这意味着利用地球观测得出的冠层结构地图对这两个指标进行尺度扩展具有潜在途径。具体而言,我们的研究结果表明,在所研究的观测范围内,将森林冠层打开20%或使森林冠层 降低一个单位,将导致 升高1.2°C。 似乎会随着冠层 增加1个单位而下降0.1,并随着冠层郁闭度呈非线性下降。考虑温度和资源的微观尺度变化被视为改善生物多样性影响预测的关键。我们的研究表明,利用遥感冠层覆盖地图绘制地表温度和地面植被绿度,可为绘制对物种重要的栖息地质量指标提供有用工具。然而,这种方法将受到用于绘制实地获取的森林冠层属性的模型预测能力的限制。此外,需要进行采样工作以捕捉 在不同日期和季节内以及不同日期和季节之间的空间和时间变化,以验证我们研究结果的可转移性。最后,虽然我们的方法表明地表温度和地面植被绿度可能是生物多样性监测中合适的栖息地质量指标,但下一步需要我们将不同受威胁状态物种的种群特征映射到这些指标在不同干扰和管理历史景观中的地图上。然后,可以利用由此得出的认识进行有针对性的景观恢复,这将有利于景观尺度上的生物多样性保护。