Faced with the challenge of balancing the needs of an ever-increasing global population with the pressure to mitigate against the impacts of climate change and protect biodiversity, we seek methods of sustainable intensification of food production. Silvopasture, where trees, shrubs and forage plants are integrated into pastureland is often proposed as an agri-environmental solution that can yield both environmental and social benefits. These benefits range from reducing the need for irrigation and chemical additives, improving welfare of livestock, increasing carbon sequestration and diversifying income streams for farmers. Yet the impacts of this type of farming on biodiversity remain relatively understudied.
We aimed to contribute to this knowledge gap by investigating the effects of silvopasture on key components of biodiversity; both plants and invertebrates. In 2020, we visited 16 farms in Caquetá, a department in the Colombian Amazon. At each farm, we performed a biodiversity assessment by surveying both invertebrates and plants in different habitat types; small forest remnants, silvopasture and traditional pasture. Two methods were employed to sample insects and spiders in each habitat; malaise traps which were left in place for seven day, and three 50 m sweep transects along which a sweep of the vegetation was taken every metre. Plants were identified in five quadrats along the same transects as the sweep samples. Identification was carried out locally, in the field or by experts at the Universidad de la Amazonia.
Both the botanical and entomological results indicate that forests, even small remnant forests on farmlands are host to unique communities with highest levels of diversity. 75% of total plant diversity was accounted for by tree species sampled in forest patches. Similarly, invertebrate community composition differed significantly between forest and traditional pasture, with silvopasture found intermediate to these two habitats. This suggests that silvopasture can support invertebrate forest species. We found higher native plant diversity in silvopasture enriched by Brachiaria compared to traditional pasture, which contradicts previous research that found that Brachiaria species can suppress and outcompete native plants.
Our results support the hypothesis that silvopasture may constitute a method of farming that is less damaging to biodiversity, in terms of both plants and invertebrates. This has implications for farm management practices and is of particular relevance with rising interest in nature-based solutions. However, our results also show that forest remnants should be a conservation priority and be preserved within farmlands.
Silvopasture; biodiversity; plants; invertebrates; sustainable intensification; forest remants