Diversity of spider fauna in the mangrove ecosystem from the coastal regions of Kerala

Abstract

Mangroves are one of the complex ecotones that support diverse faunal assemblages. and many diversity studics have been carried out in mangroves: yet, the diversity of the order Arancac remains critically overlooked. This study systematically explores the diversity. functional composition, regional endemism, and associations with vegetation and abiotic variables. as well as the responses to selected anthropogenic pressure factors. A combination of standardised line transect method with various collection techniques yielded 191 species under 102 genera and 21 families belonging to 8 foraging guilds from the 20 mangrove patches selected from 10 districts. Araneidae and Salticidae are the dominant familics from mangrove ecosystems. Site 9 — Kollam reported as the species-rich sampling station, followed by Kannur (Site 2) and Kozhikode (Site 3). Species-poor sites were Ernakulam (Site 6) and Alappuzha (Site 7). Classic richness and diversity indices exposed significant spatial heterogeneity. with the highest diversity documented in florally complex mixed mangrove patches. Guild analysis identified orb web weavers and other hunters as dominant functional groups, reflecting substrate variability and canopy stratification. Canopy cover, temperature, and humidity played a significant role in the community composition of spiders. Even though plastic pollution is visibly significant, it hasn’t contributed much to {he community shifts of spiders in various mangrove patches. Deforestation and logging serve as the major drivers of spider assemblage in the habitat. True endemism was absent in mangroves, but the presence of site-specitic endemics emphasises the importance of habitat complexity in maintaining the healthy spider community. The study lays a foundational framework in understanding the diversity. ecological response, and site specificity in Kerala's mangrove ecosystems. Incorporating molecular techniques for species inventory, genus-based behavioural and ecological studies o unveil detailed guild composition, and an in-depth understanding of some pollution variables could ’ help to unlock the conservation potential of this overlooked group of inveriebrates.