The Presence of IUCN Red List Tree Species in Dependence of Site Characteristics in the Vietnamese Cat Ba National Park

Abstract

Rare or endangered tree species are important components of forest ecosystems and play a crucial role in management and conservation. Understanding what influences their presence is critical for managers, conservationists and planners. This study presents results of a comprehensive inventory of the tree species and site characteristics in the Vietnamese Cat Ba National Park (CBNP). An adaptive cluster sampling technique was applied to study the effect of human disturbance, soil properties, and terrain conditions on the presence of IUCN Red List tree species (all individuals > 5 cm diameter at breast height) in three strictly protected areas in CBNP, which have varying levels of isolation. Data from 239 sample plots (500 m2 each) were analyzed. Tree species recorded during the inventory were assigned to two categories: IUCN Red List and other. Our results showed that site characteristics differed in the three protected areas along with the presence of IUCN Red List tree species. IUCN Red List tree species were more frequently found on less favorable soils (low soil depth) and in terrain with more pronounced slopes and with a higher rock surface area (%). However, there is no indication from existing information on the autecology of the different Red List species that the site conditions hosting the species are the ones favored by the species, even on the contrary for some. Although direct signs of human activity (paths, animal traps) could not be related to the presence of Red List tree species, the data suggest that the accessibility of the sites is a strong negative driver for the presence of Red List tree species. We conclude that protection of the forests of the Cat Ba Island should be stricter to allow the IUCN Red List tree species to grow under more appropriate conditions, which then would allow studying their ecology in more detail. This would further allow deriving more precise recommendations for their future protection.

Tree Regeneration Characteristics in Limestone Forests of the Cat Ba National Park, Vietnam

“…Other secondary forests are restored moist evergreen, wetland, and bamboo forests, as well as mangrove forests (comp. Pham, et al [47]). There are also former plantations in the park [52,93].…”

“…To estimate soil depth (S_SD) a steel rod was used. Soil depth per plot was de ned as mean depth of ve measurements across the plot (more details in Pham, et al [47]).…”

“…The size of the areas is about 1916, 600, and 1560 ha, respectively. The accessibility follows the same order, mainly due to the elevation, whereas ISA is additionally separated from the accessible part of the park, through water (more details in Pham, et al [47]).…”

“…Their results indicated that tree regeneration density in intensively managed forests was signi cantly higher than in low impact and unlogged forests. However, to our knowledge, no study has yet addressed natural forest regeneration in the limestone forests of Vietnam, even though they are diversity hotspots and habitat for many threatened tree species [47].…”

Assessing and modelling socio-ecological interactions of sacred forests in northwestern Greece

“…flora: Shackleton et al, 2020;Ojiambo and Scherm, 2010;Philippi, 2005;fauna: Cassel et al, 2020;Noon et al, 2006). In particular, it is used to assess ecological populations that tend to aggregate in clusters and are sufficiently rare in the environment (Pham et al, 2020;de Souza et al, 2020).…”