Data from: Sustainable harvesting of non-timber forest products based on ecological and economic criteria

Harvesting of highly valuable non-timber forest products (NTFPs) has been considered a win-win strategy where local people profit while conserving forest biodiversity and ecosystem services. Nevertheless the sustainability of NTFP harvesting has been debated as the nature of NTFPs, harvesting regimes, and scale of commercialization are highly heterogeneous and few studies have evaluated the cumulative ecological and economic effects of such regimes. Here, we assessed the medium-term (10 years) sustainability of NTFP harvesting, using Chameadorea palm leaves, a major NTFP from Mesoamerica that is highly valued in the international floral industry, as a case study. We used an experimental ecological study and an economic assessment to analyse the sustainability of leaf harvesting in C. ernesti-augustii. A four-year leaf removal experiment was conducted to assess effects of increasing levels of defoliation (0%, 25%, 50%, 75%, 100% leaf removal, biannually) on palm survivorship, leaf production and leaf quality. Results of this experiment were combined with estimations of harvest economic value to make projections of the availability of leaves and profit per unit area. Finally, we determined harvesting regimes that maximize profit while maintaining medium-term viability of exploited populations. Palms tolerated up to 50% chronic defoliation, but higher defoliation levels reduced survivorship, leaf production, and leaf quality. In the long-term, this 50% defoliation level maximized harvest volume and profit without significantly affecting palm survival and leaf quality. Our results show that harvesters face the dilemma of either maximizing short-term income leading to rapid exhaustion of stocks, or maintaining exploited populations but maximizing income in the long-term. Synthesis and applications. Our study shows that intermediate harvesting levels (≤ 50% leaf removal) are needed to achieve long-term sustainability of Chameadorea palm leaves. Results of this study have an immediate application for the amendment of the official Mexican law, which enables higher harvesting intensities of Chamaedorea leaves, and for the design of sustainable management strategies. Applications of such strategies should consider community-based management, fair markets, regulating norms, as well as a thorough communication among stakeholders.高价值非木材林产品（non-timber forest products, NTFPs）的采收一直被视为双赢策略：当地居民可从中获利，同时保护森林生物多样性与生态系统服务。然而，非木材林产品采收的可持续性一直存在争议，原因在于这类产品的属性、采收模式以及商业化规模均存在高度异质性，且鲜有研究评估此类采收模式累积的生态与经济效应。 本研究以中美洲地区在国际花卉产业中极具价值的代表性非木材林产品——查梅多雷亚棕榈叶（Chameadorea palm leaves）为案例，评估了非木材林产品采收的中期（10年尺度）可持续性。我们采用生态实验与经济评估相结合的方法，分析了恩氏查梅多雷亚棕榈（Chamaedorea ernesti-augustii，文中简称C. ernesti-augustii）的叶片采收可持续性。 本研究开展了为期四年的叶片移除实验，以评估不同落叶强度水平（每半年开展一次处理，分别移除0%、25%、50%、75%、100%的叶片）对棕榈存活率、叶片产量与叶片品质的影响。将该实验结果与采收经济价值估算相结合，我们可预测单位面积的叶片供应量与利润。最终，我们确定了在维持被采收种群中期存续能力的同时实现利润最大化的采收模式。 实验结果表明，棕榈可耐受高达50%的持续性落叶，但更高的落叶强度会降低其存活率、叶片产量与叶片品质。长期来看，50%的落叶强度可在不对棕榈存活与叶片品质造成显著影响的前提下，最大化采收量与利润。本研究结果显示，采收者面临两难抉择：要么最大化短期收入，导致资源快速枯竭；要么维持被采收种群存续，从而实现长期收入最大化。 综合与应用。本研究表明，要实现查梅多雷亚棕榈叶采收的长期可持续性，需采用中等采收强度（≤50%叶片移除量）。本研究结果可直接用于修订墨西哥现行官方法规——该法规目前允许更高强度的查梅多雷亚棕榈叶采收，同时也可用于可持续管理策略的设计。此类策略的实施需考虑基于社区的管理模式、公平市场体系、监管规范，以及利益相关方之间的充分沟通。