Department of Environmental Science, Rhodes University, Makhanda, South Africa.
PLoS One. 2023 Apr 5;18(4):e0283900. doi: 10.1371/journal.pone.0283900. eCollection 2023.
Investigating the concurrent impacts with harvesting on 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 B. 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 first and second harvests and at end of 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 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 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.
研究与采集同时对野生蔬菜的影响可以指导它们的可持续管理，同时有助于理解对 NTFP 物种的这种影响。本研究调查了两种野生蔬菜的叶生产、形态和生长对干旱和叶采集同时影响的反应。采用随机温室实验，对 1334 株苋菜和 391 株马齿苋进行了实验。首先通过 6 个干旱胁迫水平和对照处理进行干旱处理。采集处理包括 4 个采集水平，并进行了两次处理。在第一次和第二次采集前和实验结束时进行了测量。数据分为两个时期（第一次和第二次采集后），并使用多元方差分析和对数线性分析进行分析。结果表明，干旱对两个物种都有显著影响。然而，苋菜对减少每日水量的适应能力比减少频率更强，而马齿苋在两种干旱胁迫下都有很强的适应能力。对于苋菜，在第一次采集后，随着采集水平的增加（有一些例外），基径、生长、叶生产和存活率都有所增加。第二次采集后，株高和叶生产减少。在马齿苋中，只有在第一次采集后，对存活率和叶生产的影响才显著。两种驱动因素的相互作用的影响对苋菜很显著，但对马齿苋不显著。结果还强调了长期高采集率对物种性能的可能负面影响，特别是在严重干旱下。在苋菜中，基径、生长、存活率和叶生产对减少灌溉量的适应能力更强，而在马齿苋中，对两种类型的干旱胁迫都有更强的适应能力。这表明在中等干旱胁迫下，这两个物种都可以维持。
