Frogs, Cocoa, and Grazing Livestock: How Humans and Amphibians Can Coexist

Agriculture in the Colombian Andes is an important economic sector that is strongly influenced by geographical diversity and the local climatic conditions. Senckenberg researcher PD Dr. Raffael Ernst and a Colombian-German research team investigated how different land use systems influence amphibian diversity in this region. In their study, published in the journal “Agriculture, Ecosystems & Environment,” they show that agroforestry systems with shade-providing plantations have the highest species diversity. Intensive agriculture, particularly cattle farming, on the other hand, has a negative impact on biodiversity. The study demonstrates that the conservation of amphibian diversity is only possible through a combination of less intensive agroforestry systems and the interlinking of natural forest fragments in a mosaic matrix structure. Isolated protected areas, on the other hand, do not have the desired effect for frogs and their ilk.

Coffee, cocoa, beans, maize, potatoes, milk, and meat production – agriculture in the Colombian Andes is an important economic sector. “Due to the elevation that ranges from 1,000 to over 3,000 meters above sea level, there exist different agricultural zones with specific crops. Small-scale farmers play a crucial role in production, often using sustainable farming methods based on traditional techniques. This creates numerous microhabitats,” explains PD Dr. Raffael Ernst from the Senckenberg Natural History Collections in Dresden, and he continues, “Due to their special biology and the diversity of reproductive strategies, amphibians are often affected by even minor changes in their habitats. This also makes them particularly susceptible to the effects of changes in land use. Nevertheless, it has been shown that agroforestry systems modified by humans can preserve a considerable diversity of amphibians.”

Only a limited number of studies to date have systematically investigated how frogs and their relatives react to different management strategies within these agroforestry systems. Ernst has now addressed this topic with a research team from Colombia and Germany. They investigated the composition of amphibian communities and their taxonomic, functional, and phylogenetic diversity in the northern Andes of Colombia. They examined montane and riparian forests as well as six different land use systems along 34 independent sampling sites – so-called transects.

“Over the course of 320 transect hours, we documented a total of 3,796 individuals involving 14 species from seven amphibian families,” reports Ernst, and he continues, “Agroforestry systems with shade-providing plantations – in the Colombian Andes, bananas are generally used as temporary shade plants in coffee and cocoa production systems – showed the highest overall amphibian species diversity. Functional and phylogenetic diversity was highest in wetlands and a riparian forest fragment.”

However, the results of the new study also leave no doubt about the harmful effects of highly intensive forms of agriculture on biodiversity, such as intensive livestock farming, according to the team of authors. Ernst issues the following warning: “Cattle farming in our study areas has led to a structural impoverishment of landscapes and a reduction in species richness. This is in line with an overwhelming body of evidence showing that agriculture – especially livestock farming – is one of the leading causes of biodiversity loss in agricultural landscapes. The newly established and legally binding targets of the Global Biodiversity Framework (GBF) will again be missed unless livestock farming is significantly reduced or alternative, less harmful forms of pasture farming are introduced.”

In summary, the research team explains that amphibian diversity cannot be protected by isolated conservation areas within an intensive land use matrix alone. While diversified agroforestry systems offer multiple opportunities for a sustainable coexistence of humans and amphibians, the interlinking of natural forest fragments and sustainable agroforestry systems in a mosaic matrix structure is crucial for the conservation of diversity, both inside and outside protected areas. The results of the study show that human-altered agroforestry systems, especially shaded plantations, can play a crucial role in maintaining amphibian diversity at all levels. By protecting the remaining vegetation and incorporating native plant species into plantations, it would also be possible to maintain the commercial value of different farming systems – e.g., for cocoa or coffee – while promoting (amphibian) diversity at the same time. “Our goal should be to maintain a mosaic landscape that combines sustainable agroforestry systems with well-connected forest fragments. It requires an integrated approach to protecting the matrix instead of a few isolated conservation areas. This could be a more promising strategy for amphibian conservation in socio-ecological production landscapes such as the Colombian Andes,” adds Ernst in conclusion.

Publication: José Pinzón, Leydy Aceros, Björn Reu, Martha Patricia Ramírez-Pinilla, Raffael Ernst (2025): Matrix-protection rather than protected area conservation can safeguard multilevel amphibian diversity in Colombian agroforestry systems. Agriculture, Ecosystems & Environment, Volume 386. https://www.sciencedirect.com/science/article/pii/S016788092500091X