Forest floor temperature and greenness link significantly to canopy attributes in South Africa’s fragmented coastal forests
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...
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| Format: | Article |
| Language: | English |
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PeerJ Inc.
2019-01-01
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| Series: | PeerJ |
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| Online Access: | https://peerj.com/articles/6190.pdf |
| _version_ | 1797423850117398528 |
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| author | Marion Pfeifer Michael J.W. Boyle Stuart Dunning Pieter I. Olivier |
| author_facet | Marion Pfeifer Michael J.W. Boyle Stuart Dunning Pieter I. Olivier |
| author_sort | Marion Pfeifer |
| collection | DOAJ |
| description | 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 (Thermalground) and ground vegetation greenness (NDVIdown) 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, LAI, and Fractional vegetation cover, FCover) developed from Landsat remote sensing data. We measured Thermalground and NDVIdown 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 LAI by one unit would result in increases of Thermalground by 1.2 °C across the range of observations studied. NDVIdown appears to decline by 0.1 in response to an increase in canopy LAI 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 Thermalground 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. |
| first_indexed | 2024-03-09T07:52:48Z |
| format | Article |
| id | doaj.art-8d123db702cd495cb42fd68f5d4370d1 |
| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T07:52:48Z |
| publishDate | 2019-01-01 |
| publisher | PeerJ Inc. |
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| spelling | doaj.art-8d123db702cd495cb42fd68f5d4370d12023-12-03T01:25:46ZengPeerJ Inc.PeerJ2167-83592019-01-017e619010.7717/peerj.6190Forest floor temperature and greenness link significantly to canopy attributes in South Africa’s fragmented coastal forestsMarion Pfeifer0Michael J.W. Boyle1Stuart Dunning2Pieter I. Olivier3Modelling, Evidence & Policy Group, SNES, Newcastle University, Newcastle Upon Tyne, United KingdomForest Ecology and Conservation Group, Silwood Park Campus, Imperial College London, Ascot, Berkshire, United KingdomSchool of Geography, Politics and Sociology, Newcastle University, Newcastle Upon Tyne, United KingdomM.A.P. Scientific Services, Pretoria, South AfricaTropical 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 (Thermalground) and ground vegetation greenness (NDVIdown) 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, LAI, and Fractional vegetation cover, FCover) developed from Landsat remote sensing data. We measured Thermalground and NDVIdown 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 LAI by one unit would result in increases of Thermalground by 1.2 °C across the range of observations studied. NDVIdown appears to decline by 0.1 in response to an increase in canopy LAI 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 Thermalground 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.https://peerj.com/articles/6190.pdfCoastal forestsForest edgesEucalyptus plantationsGround surface temperatureNDVIHabitat microclimate |
| spellingShingle | Marion Pfeifer Michael J.W. Boyle Stuart Dunning Pieter I. Olivier Forest floor temperature and greenness link significantly to canopy attributes in South Africa’s fragmented coastal forests PeerJ Coastal forests Forest edges Eucalyptus plantations Ground surface temperature NDVI Habitat microclimate |
| title | Forest floor temperature and greenness link significantly to canopy attributes in South Africa’s fragmented coastal forests |
| title_full | Forest floor temperature and greenness link significantly to canopy attributes in South Africa’s fragmented coastal forests |
| title_fullStr | Forest floor temperature and greenness link significantly to canopy attributes in South Africa’s fragmented coastal forests |
| title_full_unstemmed | Forest floor temperature and greenness link significantly to canopy attributes in South Africa’s fragmented coastal forests |
| title_short | Forest floor temperature and greenness link significantly to canopy attributes in South Africa’s fragmented coastal forests |
| title_sort | forest floor temperature and greenness link significantly to canopy attributes in south africa s fragmented coastal forests |
| topic | Coastal forests Forest edges Eucalyptus plantations Ground surface temperature NDVI Habitat microclimate |
| url | https://peerj.com/articles/6190.pdf |
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