Analysis of land cover dynamics in Mozambique (2001–2016) Cianciullo, Silvio; Attorre, Fabio; Trezza, Francesca Romana ...
Atti della Accademia nazionale dei Lincei. Rendiconti Lincei. Scienze fisiche e naturali,
03/2023, Letnik:
34, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Land cover change (LCC) is a complex and dynamic process influenced by social, economic, and biophysical factors that can cause significant impacts on ecological processes and biodiversity ...conservation. The assessment of LCC is particularly relevant in a country like Mozambique where livelihood strongly depends on natural resources. In this study, LCC was assessed using a point-based sampling approach through Open Foris Collect Earth (CE), a free and open-source software for land assessment developed by the Food and Agriculture Organization of the United Nations. This study aimed to conduct an LCC assessment using CE for the entire Mozambique, and according to three different land classifications: administrative boundaries (provinces), ecoregions, and protected vs unprotected areas. A set of 23,938 randomly selected plots, with an area of 0.5 hectares, placed on a 4 × 4 km regular grid over the entire country, was assessed using CE. The analysis showed that Mozambique has gone through significant loss of forest (− 1.3 Mha) mainly to the conversion to cropland. Deforestation is not occurring evenly throughout the country with some provinces, such as Nampula and Zambezia, characterized by higher rates than others, such as Gaza and Niassa. This result can be explained considering a combination of ecological and socio-economic factors, as well as the conservative role played by the protected areas. Our study confirmed that LCC is a complex phenomenon, and the augmented visual interpretation methodology can effectively complement and integrate the LCC analyses conducted using the traditional wall-to-wall mapping to support national land assessment and forest inventories and provide training data for environmental modeling.
Land productivity dynamics in Socotra Island (Yemen) Rezende, Marcelo; Riccardi, Tullia; Malatesta, Luca ...
Atti della Accademia nazionale dei Lincei. Rendiconti Lincei. Scienze fisiche e naturali,
09/2020, Letnik:
31, Številka:
3
Journal Article
Recenzirano
Socotra, the largest of four islands in the Socotra archipelago (Yemen), is characterized by high geo-morphological and biological diversity. Traditional management of land resources has been ...impacted by cultural shifts, globalization and urban expansion. In addition, the island has been affected by climate impacts, such as droughts and recent cyclones causing significant economic and environmental damage. Our study presents an analysis of the dynamics of the vegetation on the island for the period 2001–2019 and highlights the status of different landscapes. We used Earth Observation techniques and the Normalized Difference Vegetation Index to assess land productivity dynamics basing on vegetation indexes derived from average resolution satellite images. The results show that although the arid landscapes of Socotra seem resilient, over 30% of the central mountainous areas of the Hageher (hosting a unique and high biodiversity) are decreasing in productivity, whereas in the lowlands (where plant diversity is relatively lower) productivity has increased significantly for the same time period, up to 40% in some areas. Given the difference in biological diversity of the sites, this study can help prioritize conservation areas and activities, which are crucial for Socotra’s terrestrial environment. The methodology applied could be replicated for continuous monitoring in the future.
We examine the distribution of Dracaena cinnabari, the Socotran Dragon’s Blood Tree, an endangered species endemic to the island of Socotra (Yemen)—and we propose an accessibility approach to its ...conservation, taking the proximity of local communities and land users into account. Using the present occurrence of D. cinnabari, we applied a machine learning algorithm (random forest classifier) to estimate the potential distribution of the species across the island (overall validation accuracy of 0.91) based on available climatic and physiographic parameters. In parallel, we used an accessibility methodology to generate a map of the energy cost of accessing potential areas from the villages. This community-focused accessibility map, combined with the potential distribution map of Dracaena cinnabari, could contribute to decision-making processes related to long-term ecological restoration and reforestation activities. With our case study, we wish to emphasize that user-focused efforts and the implementation of sustainable land practices should play key roles in conserving endangered tree species.
Long-term spatial studies are crucial for understanding how the Earth's surface has changed. Before satellite imagery, landscapes were monitored using black and white (B&W) aerial photographs. ...However, surveys were infrequent and image analysis was a manual process that was both time-consuming and costly. In this study, we created a composite of high spatial resolution (0.5–0.75 m) B&W aerial images from 1939–1944, covering about 91% of Kruger National Park (KNP)’s nearly 2 million ha. We used this to produce the first historical woody cover (tall trees and shrubs) map of KNP, which until now was only partially understood through fragmented descriptions in period literature and small-area case studies. We established a supervised learning workflow using Google Earth Engine (GEE) which included performing an Object-based Image Analysis (OBIA) with a Random Forest classifier. This approach, enhanced by integrating texture, shape, neighboring features, and spectral variables into the training/validation dataset, enabled the identification of woody vegetation from B&W landscape objects. To enhance accuracy, we guided our sampling method using vegetation types with comparable woody cover and species composition. Initially, we tested our method on a smaller set of images (25 km2), and after confirming its effectiveness, we then expanded the approach to cover all available historical aerial imagery. Our results show that in 1939–1944, 26% of KNP was covered in woody vegetation (overall accuracy of 89%, producer's accuracy (non-woody = 88%, woody = 90%), and user's accuracy (non-woody = 90%, woody = 87%)). The importance of geological substrate in driving vegetation pattern is reflected in a higher woody cover percentage on granite (28%) than on basalt (21%) soils, with the lowest woody cover on northern basalts (11%) and the highest on north-central granites (32%). This study highlights the potential of GEE and OBIA for analyzing large-area, high spatial resolution B&W aerial photographs in a systematic and efficient manner and the importance of creating large-scale historical land cover baselines to support environmental planning and landscape management.
•Historical aerial images provide valuable insight into long-term ecosystem changes.•First historical woody cover map of Kruger National Park, South Africa (1939–1944).•Object-based image analysis applied to large-area black-and-white aerial images.•Supervised learning workflow using open-source geospatial platform Google Earth Engine.•Applications for large-area land cover assessments and environmental planning.
We examine the distribution of Dracaena cinnabari, the Socotran Dragon’s Blood Tree, an endangered species endemic to the island of Socotra (Yemen)—and we propose an accessibility approach to its ...conservation, taking the proximity of local communities and land users into account. Using the present occurrence of D. cinnabari, we applied a machine learning algorithm (random forest classifier) to estimate the potential distribution of the species across the island (overall validation accuracy of 0.91) based on available climatic and physiographic parameters. In parallel, we used an accessibility methodology to generate a map of the energy cost of accessing potential areas from the villages. This community-focused accessibility map, combined with the potential distribution map of Dracaena cinnabari, could contribute to decision-making processes related to long-term ecological restoration and reforestation activities. With our case study, we wish to emphasize that user-focused efforts and the implementation of sustainable land practices should play key roles in conserving endangered tree species.
