Abstract Detail

Ecology

Vera, Roy [1], Cota-Sanchez, Hugo [2], Grijalva, Jorge [3].

Tree beta diversity explains changes in soil properties in cocoa agroecosystems in conjunction with shifting agriculture.

The decrease in carbon capture, water retention, and nutrient cycling required for optimal climate, water, and soil fertility is a major global concern. The decline of such ecosystem services is a consequence of rapid deforestation and degradation of forest landscapes. Shifting agriculture (SA), a common practice in tropical areas involving fallow intervals between crop cycles, allows the recovery of plant communities and soil fertility. However, the reduction of resting periods has adversely influenced forest and soil depletion. Because agroforestry systems (AFS) are believed to play an important role in buffering adverse environmental outcomes, we investigated whether beta diversity in AFSs reverses the effect of reduced SA's fallow periods in the soil structure in cocoa (Theobroma cacao) agrosystems. Our objectives were: 1) quantifying the ecological relationship between floristic composition and soil properties within the cocoa AFS with increasing levels of intensification in SA; 2) determining whether the effects of changes in floristic composition of cocoa AFS on the soil’s chemical and physical structure and nutrient content under different SA fallow periods are restricted to certain tree strata; and 3) investigating the relationships between chemical-physical soil properties with the forest's capacity to support more diverse vegetation. Quantitative analyses revealed that AFSs in combination with SA buffers the negative effects of intensive land-use on soil productivity. The arboreal cover maintains soil fertility favouring crop performance and food sustainability while enhancing the resilience capacity of the ecosystem. Nonetheless, the role of beta diversity is fundamental to balance ecosystem services. Quite feasible, the dominance of certain tree species is essential to maintain adequate levels of nutrient cycling dynamics under more intensified fallow cycles, whereas some other species have an apparent effect on soil acidity. In conclusion, the combination AFS-SA embodies a harmonious farming system designed to produce food supplies for human well-being while preserving plant diversity facilitating natural ecological corridors for native flora and fauna. This anthropological and biological amalgamation preserves ecosystem structure, integrity, and ultimately the functional dynamics of natural landscapes with increased forest capacity as a sink for CO2.

1 - University Of Saskatchewan, Biology, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada
2 - University Of Saskatchewan, Department Of Biology, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada
3 - Universidad Central del Ecuador, Medicina Veterinaria y Zootecnia, Jerónimo Leiton y Gatto Sobral, Quito, Pichincha, 170521, Ecuador

Keywords:
Agroecosystems
Biodiversity
plant-soil feedback
ecosystem services
Beta diversity.

Presentation Type: Oral Paper
Session: ECO5, Ecology 5: Plant and Community Response to the Environment and Stressors
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 1:15 PM
Number: ECO5004
Abstract ID:439
Candidate for Awards:Ecological Section Best Graduate Student Paper