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Data for: Concurrent impacts with harvesting on NTFP plants

Cite this dataset

Sinasson Sanni, Koupamba Gisele (2022). Data for: Concurrent impacts with harvesting on NTFP plants [Dataset]. Dryad.


Investigating the concurrent impacts of harvesting wild vegetables can guide their sustainable management while contributing to the understanding of such impacts on NTFP species. This study investigated leaf production, morphological and growth responses to the concurrent impacts of drought and leaf harvesting between two wild vegetables. A randomized greenhouse experiment was implemented with 1,334 plants of Amaranthus sp. and 391 of Bidens pilosa. A drought treatment was first implemented through six levels of drought stress and a control treatment. The harvesting treatment consisted of four harvesting levels and was implemented twice. Measurements were recorded before the first and second harvests and at the end of the experiment. Data were separated into two periods (after first and second harvests) and analyzed using Multivariate Analysis of Variance and log-linear analysis. The results showed significant effects of drought on both species. However, Amaranthus sp. appeared more resilient to reduction in the daily amount of water than reduction in the frequency, while B. pilosa was resilient under both facets of drought stress. For Amaranthus sp., basal diameter, its growth, leaf production and survival increased with increase in the harvesting level (with some exceptions) after first harvest. After second harvest, there was a decrease in plant height and leaf production. In B. pilosa, the impact was only significant on survival and leaf production (after first harvest). The effect of the interaction of the two drivers was significant for Amaranthus sp. but not for B. pilosa. The results also highlighted the possible negative impact of a prolonged high rate of harvesting on the species' performance, especially under severe drought. Basal diameter, its growth, survival and leaf production appeared more resilient to reduced amounts of watering in Amaranthus sp. and under both types of drought stress for B. pilosa. This suggests that both species could be sustained under medium drought stress.


Data was collected through a greenhouse experiment conducted at Rhodes University, Makhanda, South Africa. After a seed germination assay, the obtained seedlings were used to investigate the concurrent impacts of drought and leaf harvesting on two important wild vegetables non-timber forest products (Amaranthus sp. and Bidens pilosa) in South Africa. The drought treatment was first implemented through six levels of drought stress (or drought treatments) including three reduced amounts of watering and three frequencies of watering, and a control treatment. The harvesting treatment consisted of four levels of harvesting (but three for B. pilosa), represented by different percentages of leaves harvested. The harvesting treatment was repeated twice during the course of the study to evaluate the impact of prolonged harvesting on the plants.

We monitored plant morphology and growth as well as leaf production and survival during the experiment. To assess the morphology and growth, we measured the shoot length (as an estimate of height) and basal diameter of the plants at three different times as follows: (i) before first harvest, before second harvest and at the end of the experiment. For leaf production, the number of leaves was recorded per plant at the three above-described measurement times. For the measurements, we used a standard ruler for the height and calipers for the basal diameter. The number of dead individuals was also recorded. 

Usage notes

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South African Research Chairs Initiative of the Department of Science and Technology and the National Research Foundation of South Africa, Award: 84379