Landscapes and Ecosystems of Tropical Limestone: Case Study of the Cat Ba Islands, Vietnam

Van, Quan Nguyen; Duc, Thanh Tran; Van, Huy Dinh

doi:10.5141/jefb.2010.33.1.023

Cited by 9 publications

(4 citation statements)

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“…The average annual temperature ranges from 24˝C to 30˝C with July as the warmest month, whereas the coolest month is January. Due to the effects of climate change, there is a higher frequency of high-temperature days (37-40˝C) and less rain, which have resulted in an increased probability of forest fires in this area [22][23][24][25].…”

Section: Description Of the Study Areamentioning

confidence: 99%

Tropical Forest Fire Susceptibility Mapping at the Cat Ba National Park Area, Hai Phong City, Vietnam, Using GIS-Based Kernel Logistic Regression

et al. 2016

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Abstract:The Cat Ba National Park area (Vietnam) with its tropical forest is recognized as being part of the world biodiversity conservation by the United Nations Educational, Scientific and Cultural Organization (UNESCO) and is a well-known destination for tourists, with around 500,000 travelers per year. This area has been the site for many research projects; however, no project has been carried out for forest fire susceptibility assessment. Thus, protection of the forest including fire prevention is one of the main concerns of the local authorities. This work aims to produce a tropical forest fire susceptibility map for the Cat Ba National Park area, which may be helpful for the local authorities in forest fire protection management. To obtain this purpose, first, historical forest fires and related factors were collected from various sources to construct a GIS database. Then, a forest fire susceptibility model was developed using Kernel logistic regression. The quality of the model was assessed using the Receiver Operating Characteristic (ROC) curve, area under the ROC curve (AUC), and five statistical evaluation measures. The usability of the resulting model is further compared with a benchmark model, the support vector machine (SVM). The results show that the Kernel logistic regression model has a high level of performance in both the training and validation dataset, with a prediction capability of 92.2%. Since the Kernel logistic regression model outperforms the benchmark model, we conclude that the proposed model is a promising alternative tool that should also be considered for forest fire susceptibility mapping in other areas. The results of this study are useful for the local authorities in forest planning and management.

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Section: Description Of the Study Areamentioning

confidence: 99%

Tropical Forest Fire Susceptibility Mapping at the Cat Ba National Park Area, Hai Phong City, Vietnam, Using GIS-Based Kernel Logistic Regression

et al. 2016

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“…In contrast to the other studied karst areas, individual limestone habitats in the Coastal Area are smaller and more fragmented. In addition, the environmental conditions of the Coastal Area differ from those inland: Cat Ba Island, for example, is characterized by warmer winters and cooler summers and is more exposed to typhoons (Do, 2014;Nguyen, Tran, & Dinh, 2010 (Vermeulen & Maassen, 2003), may limit the shell size.…”

Section: Discussionmentioning

confidence: 99%

Competition matters: Determining the drivers of land snail community assembly among limestone karst areas in northern Vietnam

Oheimb

Hirano

et al. 2018

Ecology and Evolution

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The insular limestone karsts of northern Vietnam harbor a very rich biodiversity. Many taxa are strongly associated with these environments, and individual species communities can differ considerably among karst areas. The exact processes that have shaped the biotic composition of these habitats, however, remain largely unknown. In this study, the role of two major processes for the assembly of snail communities on limestone karsts was investigated, interspecific competition and filtering of taxa due to geographical factors. Communities of operculate land snails of the genus Cyclophorus were studied using the dry and fluid‐preserved specimen collections of the Natural History Museum, London. Phylogenetic distances (based on a Bayesian analysis using DNA sequence data) and shell characters (based on 200 semilandmarks) were used as proxies for ecological similarity and were analyzed to reveal patterns of overdispersion (indicating competition) or clustering (indicating filtering) in observed communities compared to random communities. Among the seven studied karst areas, a total of 15 Cyclophorus lineages were found. Unique communities were present in each area. The analyses revealed phylogenetic overdispersion in six and morphological overdispersion in four of seven karst areas. The pattern of frequent phylogenetic overdispersion indicated that competition among lineages is the major process shaping the Cyclophorus communities studied. The Coastal Area, which was phylogenetically overdispersed, showed a clear morphological clustering, which could have been caused by similar ecological adaptations among taxa in this environment. Only the community in the Cuc Phuong Area showed a pattern of phylogenetic clustering, which was partly caused by an absence of a certain, phylogenetically very distinct group in this region. Filtering due to geographical factors could have been involved here. This study shows how museum collections can be used to examine community assembly and contributes to the understanding of the processes that have shaped karst communities in Vietnam.

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“…In this study, the landscape pattern index was employed to depict the structural characteristics of land use types and KD classes, allowing for a better understanding of the spatial and temporal changes in land use types and KD landscapes. Building upon previous research [32][33][34][35] and considering the ecological significance and research objectives, six metrics were selected: the Shannon diversity index (SHDI), the uniformity index (SEDI), the fragmentation index (FN), the spreading index (CONTAG), the fractional dimension index (FD), and the aggregation index (AI). To facilitate the analysis, the land use type and KD grade distribution data in 2009 and 2019 were converted into 5 m × 5 m raster data.…”

Section: Landscape Pattern Indexmentioning

confidence: 99%

Response of the Desertification Landscape Patterns to Spatial–Temporal Changes of Land Use: A Case Study of Salaxi in South China Karst

Shu

Xiong

Zhang

2023

Land

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Land use change and karst desertification (KD) are interdependent. It is crucial to investigate the relationship between the KD landscape and spatial–temporal changes in land use for effective and sustainable KD management practices in karst plateau mountains. In this study, we analyzed the spatial and temporal characteristics, evolution in the pattern of land use, and KD in the Salaxi study area from 2009 to 2019, using the landscape pattern index and KD evolution trajectories, and discussed their response relationships. The results revealed the following: (1) In Salaxi, cultivated land predominantly transformed into shrubland, grassland, and woodland. The area of grassland, construction land, and garden land significantly increased, with respective increments of 379.85%, 157.14%, and 1847.81%. Conversely, the area of unutilized land decreased from 53.56 hm2 to 8.55 hm2, with the proportion declining from 0.62% to 0.10%. KD primarily occurs in shrubland, cultivated land, and woodland. (2) The areas of non-KD and potential KD have increased. There was a noticeable conversion of light and medium KD into potential KD, with areas of 1206.84 hm2 and 459.47 hm2, respectively. The KD landscape is dominated by stable and weakening ecological restoration. The comprehensive ranking of the incidence of soil KD in the study area is as follows: yellow soil > yellow-brown soil > coarse bone soil > limestone soil > purple soil. (3) The land use landscape index, the evenness index, and the fragmentation index in the demonstration area increased by 0.263, 0.120, and 0.534, respectively, while the KD landscape index, evenness index, and fragmentation index decreased by 0.360, 0.123, and 1.098, respectively. Additionally, the spreading index and aggregation index of the land use landscape decreased by 9.247 and 3.086, respectively, while the KD landscape’s spreading index and aggregation index increased by 6.688 and 0.430, respectively. Both the sub-dimension indexes of the land use landscape and the KD landscape increased by 0.009. Overall, the landscape pattern of KD changes in response to land use variations and different land types exhibited varying responses to KD. The study of KD and land use landscape patterns can provide references for national strategies on KD control and the development of ecological industries.

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Landscapes and Ecosystems of Tropical Limestone: Case Study of the Cat Ba Islands, Vietnam

Cited by 9 publications

References 0 publications

Tropical Forest Fire Susceptibility Mapping at the Cat Ba National Park Area, Hai Phong City, Vietnam, Using GIS-Based Kernel Logistic Regression

Tropical Forest Fire Susceptibility Mapping at the Cat Ba National Park Area, Hai Phong City, Vietnam, Using GIS-Based Kernel Logistic Regression

Competition matters: Determining the drivers of land snail community assembly among limestone karst areas in northern Vietnam

Response of the Desertification Landscape Patterns to Spatial–Temporal Changes of Land Use: A Case Study of Salaxi in South China Karst

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