Current and future effects of global change on a hotspot's freshwater diversity

Abstract

Deforestation, climate change and invasive species constitute three global threats to biodiversity that act synergistically. However, drivers and rates of loss of freshwater biodiversity now and in the future are poorly understood. Here we focus on the potential impacts of global change on freshwater mussels (Order Unionida) in Sundaland (SE Asia), a vulnerable group facing global declines and recognized indicators of overall freshwater biodiversity. We used an ensemble of distribution models to identify habitats potentially suitable for freshwater mussels and their change under a range of climate, deforestation and invasion scenarios. Our data and models revealed that, at present, Sundaland features 47 and 32 Mha of habitat that can be considered environmentally suitable for native and invasive freshwater mussels, respectively. We anticipate that by 2050, the area suitable for palm oil cultivation may expand between 8 and 44 Mha, representing an annual increase of 2-11%. This is expected to result in a 20% decrease in suitable habitat for native mussels, a drop that reaches 30% by 2050 when considering concomitant climate change. In contrast, the habitat potentially suitable for invasive mussels may increase by 44-56% under 2050 future scenarios. Consequently, native mussels may compete for habitat, food resources and fish hosts with invasive mussels across approximately 60% of their suitable range. Our projections can be used to guide future expeditions to monitor the conservation status of freshwater biodiversity, and potentially reveal populations of endemic species on the brink of extinction. Future conservation measures-most importantly the designation of nature reserves-should take into account trends in freshwater biodiversity generally, and particularly species such as freshwater mussels, vital to safeguard fundamental ecosystem services.

Research priorities for freshwater mussel conservation assessment

“…In contrast, agricultural drainages from paddy fields in Japan positively affect mussels living in rivers and agricultural ditches due to increased food abundance and more suitable water temperatures (Nakano, 2017;Nishio et al, 2017). Hence, assessment of the degree of a species' tolerance to impacts associated with land-use change (e.g., sedimentation, turbidity, nutrient pollution) is of paramount importance for predicting the present and future impacts on freshwater mussel assemblages (Gallardo et al, 2018).…”

Non-native mollusks throughout South America: emergent patterns in an understudied continent

“…Biological invasions have been recognized as one of the greatest threats to biodiversity in the world (Rodríguez 2001;Bellard et al 2013;Gallardo et al 2018). When non-native species invade, they can modify the community structure and the ecosystems function (Simberloff et al 2012), and also represent a serious socio-economic threat (Pejchar and Mooney 2009).…”

On the RIP: using Relative Impact Potential to assess the ecological impacts of invasive alien species

“…Indeed, the number of confirmed invasive species per country has risen around 70% since 1970 (IPBES 2019). The combination of species introductions with changing climate (Seebens et al 2015, Gallardo et al 2018 and other anthropogenic impacts (MacDougall andTurkington 2005, Didham et al 2007) is aiding species establishment and spread, with the number of invasive species unlikely to saturate in the near future (Seebens et al 2017). While the effects of invasive species can be benign (invasiveness is not correlated with impact: Ricciardi and Cohen 2007), many invasive species have severe ecological consequences that drive negative economic, social and health implications (Laverty et al 2015a,b).…”