In 2021, we received approximately 50 applications from the ASA Start-up Conservation Grants call. On the one hand, this high number of applications demonstrates there are amazing amphibian conservation projects being conducted worldwide. However, it also illustrates how many organisations are in urgent need of funding to conserve amphibians. Because our resources are unfortunately limited, the ASA is only able to fund a small proportion of the projects that have applied for our grants. However, because we consider all projects to be important for advancing amphibian conservation around the world, we would like to publicise them on our platforms, to help draw the attention of other funding entities, potential collaborators and/or partners.

Below you can learn more about the project Presence and density estimates of the pathogenic fungus Batrachochytrium dendrobatidis in different substrates proposed by Instituto de Zoología y Ecología Tropical de la Universidad Central de Venezuela and Instituto Venezolano de Investigaciones Científicas (Ingrid Márquez[email protected]; Onil Ballestas, Margarita Lampo).

Emergent infectious diseases have been recognized as a main threat for biodiversity in last decades. The pathogenic fungus Batrachochytrium dendrobatidis (Bd), that causes chytridiomycosis, infects amphibian skin disrupting normal skin function, ion equilibrium and leads in many cases to the death of infected hosts (Voyles et al. 2007; Voyles et al. 2009; Voyles et al. 2011). Bd has been linked to declines, local extirpations, and extinction of amphibians worldwide, although the exact number remains controversial (see Scheele et al. 2019 and Lambert et al. 2020).

The Bd free-living form is an aquatic flagellated zoospore (Longcore et al. 1999; Johnson and Speare, 2003). The encysted zoosporangium in the amphibian skin produces new zoospores and then releases them to the environment (Berger et al. 1998; Berger et al. 2005; Longcore et al. 1999; Nichols et al. 2001). Bd zoospores can survive up to seven weeks in lake water (Johnson and Speare, 2003). Mathematical modelling has demonstrated that the fungus’ ability to survive outside its host in abiotic reservoirs is a critical factor driving amphibian extinctions (Mitchell et al. 2008; Louca et al. 2013). Model simulations of the dynamics of Bd infection in harlequin toads showed that variations in the life expectancy of the zoospores in the environment influence the transitions between coexistence and extinction of host population (Ballestas et al. 2021).

Despite the key role played by the free-living zoospore in the Bd-amphibian dynamics, the distribution of the zoospores in the environment is largely unknown. One study showed that zoospores can be found in the environment all year-round (Chestnut et al. 2014). Identifying environmental reservoirs where amphibian are exposed to Bd is a necessary step for reducing transmission rates, a potential strategy to minimize the impact of chytridiomycosis on amphibian populations.

Atelopus cruciger is currently listed as Critically Endangered by the IUCN. Remnant populations in Venezuela have maintained few hundred mature individuals for almost one decade, despite the presence of the fungus. Because Bd transmission is low, high juvenile recruitment compensates for the disease-associated mortality. This means that climatic scenarios that increase Bd transmission could rapidly push these populations to a collapse, and possibly the species to extinction. Our goal is to identify abiotic reservoirs where exposure to Bd zoospores is high to design management strategies that can reduce pathogen transmission in wild populations.

To identify reservoirs of zoospore in the environment, we will sample toads and the substrates where they are found for Bd zoospores in one remnant population of harlequin toads known to persist with endemic infection. Toads will be sampled using non-invasive swabbing and released and substrates by collecting samples of water, leaves, sand or swabbing rock surfaces. Paired toad-substrate samples will maximize the probability of detection and allow for the evaluation of the detectability of zoospores in substrates (Chestnut et al. 2014). Bd will be detected from samples and swabs using Rt-PCR according to published protocols.

We are seeking for patrons and potentials donors to this initiative; we thank in advance all the help we may have.

Photo: Atelopus cruciger (by Katiuska González)