The impacts of tropical agriculture on biodiversity: A meta-analysis

1.   Biodiversity underpins all food production and strengthens
agricultural resilience to crop failure. However, agricultural expansion
is the primary driver of biodiversity loss, particularly in the tropics
where crop production is increasing and intensifying rapidly to meet a
growing global food demand. It is therefore crucial to ask, how do
different crops and crop production systems impact biodiversity? 2.
  We first use the FAO database of harvested crop area to explore
temporal changes in crop area and intensification across the entire
tropical realm. We show that the harvested area of tropical crops has more
than doubled since 1961, with ever-increasing intensification. The
harvested area in 2019 was 7.21 million km2, equivalent to 5.5% of global
ice-free land area, or 11.5% of land area in the tropics. 3.  
Second, we conducted a meta-analysis of 194 studies and 1,364 pairwise
comparisons to assess the impact of tropical agriculture on biodiversity,
comparing biodiversity values in food crop sites versus natural reference
habitats. 4.   Our meta-analysis shows that crop type, rotation
time and level of shading are important determinants of biodiversity
assemblages. Perennial tropical crops that are grown in shaded plantations
or agroforests (e.g., banana and coffee) support higher biodiversity,
while crops cultivated in unshaded and often homogeneous croplands (e.g.,
maize, sugarcane, and oil palm), and particularly annual crops, have
impoverished biodiversity communities. 5.   Policy implications:
Our findings highlight the increasing agricultural expansion and
intensification over the last sixty years and inform our understanding of
how different crops and crop production systems impact biodiversity.
Furthermore, they provide insight into the long-term sustainability of
tropical food production and may serve as a warning sign for agricultural
systems that rely on the ecosystem services provided by biodiversity.