Effects of patch size on liana diversity and distributions in the tropical montane evergreen forests of the Nilgiri Mountains, southern India

Abstract

Abstract:We investigate the effect of patch size on liana diversity and distribution in 19 patches of montane evergreen forest in the Nilgiri hills, Western Ghats, southern India. Additionally, we examined how liana species richness and community assemblage in both edge (within 10 m of the forest edge) and interior regions of forest patches respond to patch size, in order to infer the impact of forest expansion or reduction on the liana communities. A total of 1276 woody liana individuals of 15 species were identified, belonging to 10 genera and nine families. Total species richness of lianas was significantly positively related to forest-patch area, both when analysed for the entire patch, in addition to both core and edge regions when examined separately. Species richness of larger lianas also showed a significant positive relationship with increasing forest patch area. Community assemblage varied with respect to forest edge, with shade-dependent species only occurring in interior patch regions, shade-averse species in edge regions, and shade-tolerant species occurring throughout. Disturbance also played a role in determining the response of liana diversity to patch size, with heavily disturbed patches showing no relationship between patch size and diversity, whereas positive relationships exist in low to moderately disturbed patches. The most significant result is the change in liana community composition between small and larger fragments. Many species present in smaller patches are also present in edge zones of larger fragments. This suggests that lianas are important structural components of montane forest ecosystems, and their compositional patterns are possibly driven by succession. Moreover, this study reveals the importance of edge effect and patch size in influencing liana species richness and compositional patterns.

Floristic Structure and Diversity of a Tropical Sub-Montane Evergreen Forest, In the Mbam Minkom Massif (Western Yaoundé)

“…Rollet (1983) estimated that the relative density in tropical forests around the world averages 552 trees/ha (dbh ≥ 10cm). The plots set in high elevation rainforest of Western Cameroon (Noumi, 2012(Noumi, , 2013 and Nigiri Indian (Mohandass and Davidar, 2009) recorded a number of trees (dbh ≥ 10cm) at 763, 1269.2 and 832 trees per hectare, respectively (Table 6). The comparison with woody plant inventories of tropical rainforests sampled in various continents showed that tree density seemed to have a similar range of variation throughout the world with however a tendency toward a rise, in densities in high altitude forests (Table 6).…”

“…(Mori et al, 1983). The highest basal areas are found in the highland rainforests of Asia (Mohandass and Davidar, 2009) (Noumi, 2013). At high altitude, the rainforests are populated by middle size and mesothermic individuals in the overhead stratum (20-25m) and even less so in the most elevated altitudes (Lebrun & Gilbert, 1954 …”

Floristic Composition and Structural Diversity of Shasha Forest Reserve in Ile-Ife, Southwestern Nigeria

“…Studies on floristic composition and structure in forests are instrumental in the sustainability of forest since they play a major role in the conservation of plant species and the management of forest ecosystems as a whole (Mohandass al., 2009;Tilman, 1988;Ssegawa and Nkuutu, 2006). The results of this study show that the floristic composition of Shasha forest reserve (119 species/ha) were higher than many other tropical forests.…”

Flowering and Fruiting Patterns of Woody Species in the Tropical Montane Evergreen Forest of Southern India

“…The study plot was established in the Korakundah Reserve Forest located 60 km from the southwestern side of the Nilgiri Headquarters (1113.617N, 7635.546E). Detailed site and topographic information is reported elsewhere 40,41 . There are many discrete patches of montane forests in the upper Nilgiri Mountains.…”

“…Furthermore, most of the natural forest areas are under high pressure from anthropogenic activities, especially agricultural expansion and human settlement. These have led to progressive forest fragmentation and isolation 40,41 . The dominant understorey species include Psychotria nilgiriensis and Lasianthus venulosus (Rubiaceae), and the dominant canopy trees are Litsea wightiana, Symplocos foliosa, Mahonia leschenaultiana and Neolitsea cassia.…”