Decline of Indigenous Crop Diversity in Colonial and Postcolonial Rwanda
Figure 2
(a) Exponential fit illustrating the dynamics of ornamental plant richness from 1900 to 2012 ( = 0.908). (b) Exponential fit depicting expansion of Kigali city area from 1907 to 2006 ( = 0.915). (c) A linear regression of domestic garden plant richness on household annual income. (d) Relative importance of garden plants with regard to their readiness to productive use [9]. Both Kigali city area and the number of garden plant species increased exponentially from late 1800s to early 21th century. Gross national income also followed a similar trend, suggesting that the influx of new plant species followed patterns of wealth accumulation. It was estimated at US$440 per capita in 1981, US$540 in 1991, US$610 in 2001, and US$1240 in 2011 (http://data.worldbank.org/, 03.10.2012). Note that the growth rate was the highest in the last 10 years (203%, from 2001 to 2011) ((a) and (b)) [16]. Other factors hold constant, socio-economic factors such that household income appears to be a powerful predictor of ornamental plant diversity around human settlements and Rwanda’s residential neighborhoods. Edible ornamentals account for more than 20% of recorded garden plants. The percentage is raised up to twofold in low-to-middle-income settlements. It decreases to 0–5% in high standard residential neighborhoods, where showy ornamentals are the most common feature ((c) and (d)).
