How will climate change affect plant—herbivore interactions? A tropical waterbird case study

Abstract

We review interactions between waterfowl and wetlands and outline the shifts that are likely to occur within these relationships through global climate change. We highlight the relative paucity of research on populations of tropical waterfowl and their food plants, and use an iconic tropical species of waterfowl, the Magpie Goose (Anseranas semipalmata), as a case study. We provide background on the known and hypothesised interactions between Magpie Geese and wetlands and provide a hypothetical framework of the mechanistic changes to these relationships through climatic change, including rises in sea level, temperature increases, elevated CO 2 levels and altered rainfall regimes. Intrusion of saline water through sea-level rise and extended periods of inundation following increased annual rainfall are the two plausible drivers of change in the wetland sedge plants that support Magpie Geese populations. We show how the relative importance of these, and other, threatening factors can be challenged with data from the field and laboratory under multiple working hypotheses. Understanding the imminent shifts in the structure of wetland plant communities and the likely response of waterfowl populations will focus management on key threats and critical habitat. This includes identification of important wetlands and the construction of buffers at them to slow salt-water intrusion.

Foraging guild membership explains variation in waterbird responses to the hydrological regime of an arid‐region flood‐pulse river in Namibia

“…, 2008). There is less knowledge of influences on waterbird communities in tropical environments (Traill, Whitehead & Brook, 2009) with the possible exceptions of some communities in Australia (e.g. Kingsford, Curtin & Porter, 1999; Tockner & Stanford, 2002; Kingsford, Jenkins & Porter, 2004) and the Niger Delta of West Africa (Cappelle et al.…”

Climate Change and Intertidal Wetlands

“…Saltmarshes and mangrove forests are important to birds providing sites for feeding, roosting and nesting [ 104 , 215 , 216 , 217 , 218 ]. A variety of birds directly eat the seeds and filamentous green algae.…”

“…A variety of birds directly eat the seeds and filamentous green algae. Increasing temperatures associated with climate change could alter a range of variables such as primary productivity and nutrient cycling which may affect abundances of macroinvertebrates with flow on impacts on birds both in terms of feeding and reproducing [ 215 , 216 , 217 , 218 ]. For example, the loss and degradation of Arctic saltmarshes from climate change is predicted to have global consequences for avifauna.…”

Wetland conservation and sustainable use under global change: a tropical Australian case study using magpie geese

“…During the dry season, birds aggregate in numbers of up to 250 000 on shallow-water floodplains, where they grub for tubers of the sedge plant Eleocharis dulcis (Frith and Davies 1961). The size of the aggregations and impact of herbivory alter wetland plant community structure (Traill et al 2009). Population models for geese suggest that present-day hunting estimates (median of 100 000 geese yr (1 ) are sustainable, assuming that current environmental conditions prevail (Brook and Whitehead 2005a).…”

“…Populations already undermined by habitat loss, over‐exploitation and competitive invasive species (Sodhi et al 2004) are now challenged by environmental perturbation through global warming (Thomas et al 2004). The potential for synergistic interactions among deterministic threats will makes matters worse (Brook et al 2008), and small, restricted populations are not likely to persist (Caughley 1994, Traill et al 2010).…”