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The Population Decline and Extinction of Darwin’s Frogs

Darwin’s Frogs are two species of frogs of the family Rhinodermatidae: Rhinoderma darwinii  (also called the Southern Darwin’s frog) and Rhinoderma rufum (also known as Chile Darwin’s frog or Northern Darwin’s frog); the first native to Chile and Argentina and the second endemic to central Chile. Both frogs are named after Charles Darwin who had previously discovered it in Chile during his world voyage on the HMS Beagle.

A peculiarity of these frogs is that species are mouth-brooding and  tadpoles develop inside the male vocal sac. 

Rhinoderma darwinii is classified since 2004 as “Vulnerable" on the IUCN Red List and Rhinoderma rufum is listed as “Critically Endangered" since 2010. The main threats to these species are drought, pine forestry and  clear-cutting of forest for R. darwinii, and he destruction of the native vegetation for R. rufum.

However, a study published in June 2013, developed by researchers at the University Andres Bello (Chile), University College London, Zoological Society of London and the University of Chile, which included extensive surveys carried out throughout the historical ranges of both species from 2008 to 2012, provide evidence that R. rufum is extinct and indicate that R. darwinii has declined to a much greater degree than previously recognized.

According with this study, the last sighting of R. rufum  based on museum archives and the scientific literature, was in 1980. Although Rhinoderma darwini can still be found across a large part of its historical range, remaining populations are small and severely fragmented. Conservation efforts for this frog should be stepped up and the species re-classified as Endangered. 

In addition, a later study (November, 2013) indicates that the amphibian disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis is also a factor in the decline of populations of Rhinoderma  species.

Photos: Top - Specimen of Rhinoderma darwinii photographed by Eric LoPresti / Bottom: Distribution Maps of Rhinoderma spp. by Soto-Azat C, Valenzuela-Sánchez A, Collen B, Rowcliffe JM, Veloso A, (2013).

Gulf of Maine shrimp have been overharvested to the point that it is necessary to halt all shrimping in order to protect the species.  

The good news is that the shrimp are well-enough studied and protected that this action may be sufficient for saving them.  The bad news is that most biodiversity does not fall under this category, but is overharvested just the same.

The sustainable economy must at some point stop
growing, but it need not stop developing. There is no reason to limit the qualitative improvement in design of products, which can increase GDP without increasing the amount of resources used. The main idea behind sustainability is to shift the path of progress from growth, which is not sustainable, toward development, which presumably is.
Original source of quote.   Extracted and compiled here
The bars on the graph represent the number of species threatened from importing (red) or exporting (blue) commodities.  For example, spider monkeys in Mexico are threatened due to habitat loss as a result of coffee and cacao (chocolate) plantations replacing native forests. Therefore, when Mexico exports coffee it is exporting 1 species threat (blue bars) and countries that import this coffee from Mexico are importing 1 threat (red bars).  

As you can see, most of the countries that are importing the highest number of threats are in the developed world (with the USA on top), and most of the countries exporting the most threats are from the developing world.  
Source: International drives biodiversity threats in developing nations, by Lenzen et al.  2012.  Nature.

The bars on the graph represent the number of species threatened from importing (red) or exporting (blue) commodities.  For example, spider monkeys in Mexico are threatened due to habitat loss as a result of coffee and cacao (chocolate) plantations replacing native forests. Therefore, when Mexico exports coffee it is exporting 1 species threat (blue bars) and countries that import this coffee from Mexico are importing 1 threat (red bars).  

As you can see, most of the countries that are importing the highest number of threats are in the developed world (with the USA on top), and most of the countries exporting the most threats are from the developing world.  

Source: International drives biodiversity threats in developing nations, by Lenzen et al.  2012.  Nature.