Impact of Urban Threats and Disturbance on the Survival of Waterbird Communities in Wetlands of Bengaluru City, India

Abstract

Threats to waterbird communities on urban wetlands in the Bengaluru city, South India are poorly known. We calculated disturbance scores for 15 lakes along a gradient from low (LDL) to high (HDL) disturbance levels based on vegetation structure and composition. HDL had the highest threat scores and the lowest number of waterbird species whereas LDL supported the highest number of species. Human activities included commercial fishing and aquaculture, and shoreline development leading to habitat fragmentation and degradation. We discuss strategies for the conservation of urban wetlands and the preservation of waterbird diversity.

Water-level controlled reservoir as refugia for waterbirds in an urban landscape

“…However, management strategies could be taken to increase local biodiversity. Previous studies show that waterbird richness and abundance increase in shallow and large wetlands, with a high shoreline complexity, number of islands, macrophyte coverage, and tree density (Hansson et al 2005;González-Gajardo et al 2009;Rajashekara and Venkatesha 2018). Thus, we advocate the creation of islands and shallow shorelines and the reproduction of natural flood cycles during dam operations, allowing for mudflats exposure (Desgranges et al 2006;Robinson and Pizo 2017).…”

“…Wetlands are highly productive and biodiverse environments, encompassing several types of natural (e.g., rivers, lakes, and floodplains) and artificial (e.g., dams, reservoirs, and rice paddies) habitats (Ramsar 2016;Tulasi et al 2017). Natural wetlands have been under continuous loss and degradation because of pollution and water extraction (Prusty et al 2017). In this scenario, artificial wetlands can play an important role in maintaining biodiversity (Cardoso and Loures-Ribeiro 2017).…”

A review of current knowledge and research priorities for conservation of lentic biodiversity in tropical wet and monsoonal urban landscapes

“…Some of the studies addressed spatial and temporal variation in gest species-specific responses to habitat features such as area (Clements et al, 2006;Razak & Sharip, 2019) and the importance of macrophyte density for odonate species richness and abundance (Wakhid et al, 2020). A positive correlation between plants and waterbird diversity was found in one study from India (Rajashekara & Venkatesha, 2018). Only one study looked at interspecies dynamics such as predator-prey relationships (Sareein et al, 2019).…”

Terrestrial threats dominate the waterbird landscape of fear in a savannah pan wetland system

“…If these species are constantly under threats that trigger flight, a significant proportion of foraging time could be lost making such sites unfavourable for them (Klein et al 1995, Blumstein 2006. Therefore, if all the other factors are constant, sites that experience constant disturbances will progressively be selected by communities skewed towards species that can swim (Rajashekara and Venkatesha 2017). Such biases will not meet tourist expectations for greater species diversity (Ian 2000), and may ultimately result in skewed ecosystem processes, for example, some food resources may remain underutilised (Gill et al 2001, McFadden et al 2017 or waterbirds may shift their feeding times and locations accordingly (Guillemain and Fritz 2002).…”

“…Wetlands face various forms of disturbances because they are focal habitats for humans and wildlife; with activities such as resource extraction and tourism; taxa reliant on them have not been spared. Wildlife populations can be impacted by disturbances especially on focal habitats such as wetlands (Schüttler et al 2009, Rajashekara andVenkatesha 2017). Disturbances negatively affect several aspects of wildlife including foraging behaviour (Guillemain and Fritz 2002), reproduction (Goering andCherry 1978, Barr 2017) and spatiotemporal occupation of habitats (Duriez et al 2005).…”