Data from: Species and population diversity in Pacific salmon fisheries underpin indigenous food security

1. Indigenous people are considered to be among the most vulnerable to food insecurity and biodiversity loss. Biodiversity is cited as a key component of indigenous food security; however, quantitative examples of this linkage are limited.
2. We examined how species and population diversity influence the food security of indigenous fisheries for Pacific salmon (Oncorhynchus species). We compared two dimensions of food security – catch stability (interannual variability) and access (season length) – across a salmon diversity gradient for 21 fisheries on the Fraser River, Canada, over 30 years, using linear regression models. We used population diversity proxies derived from a range of existing measures because population-specific data were unavailable.
3. While both population and species diversity were generally associated with higher catch stability and temporal access, population diversity had a stronger signal. Fisheries with access to high species diversity had up to 1.4 times more stable catch than predicted by the portfolio effect and up to 1.2 times longer fishing seasons than fisheries with access to fewer species. Fisheries with access to high population diversity had up to 3.8 times more stable catch and 3 times longer seasons than fisheries with access to fewer populations.
4. Catch stability of Chinook Oncorhynchus tshawytscha and sockeye O. nerka fisheries was best explained by the number of populations and conservation units respectively that migrate past a fishery en route to spawning grounds. Similar population diversity metrics were important explanatory variables for season length of sockeye, pink O. gorbuscha, coho O. kisutch, and chum O. keta fisheries.
5. Synthesis and applications. We show an empirical example of how multiple scales of biodiversity support food security across a large watershed and suggest that protecting fine-scale salmon diversity will help promote food security for indigenous people. The scales of environmental assessments need to match the scales of the socio-ecological processes that will be affected by development. We illustrate that upstream projects that damage salmon habitat could degrade the food security of downstream indigenous fisheries, with implications to Canadian indigenous peoples and to watersheds around the world where migratory fishes support local fisheries.

1. 原住民群体被认为是最易受粮食不安全与生物多样性丧失影响的人群之一。生物多样性被视作原住民粮食安全的关键组成部分，但二者之间关联的量化例证却较为有限。
2. 本研究探究了物种与种群多样性对太平洋鲑（Oncorhynchus）原住民渔业粮食安全的影响。我们依托线性回归模型，针对加拿大弗雷泽河沿岸21处渔业开展了为期30年的研究，对比了粮食安全的两个维度——渔获稳定性（年际变异性）与可及性（渔期长度），并覆盖了鲑鱼多样性梯度。由于缺乏种群特异性数据，我们采用了基于一系列现有测度构建的种群多样性替代指标。
3. 尽管种群多样性与物种多样性均通常与更高的渔获稳定性和更长的季节性可及性相关，但种群多样性的影响信号更强。相较于物种更少的渔业，拥有高物种多样性的渔业其渔获稳定性最高可达投资组合效应（portfolio effect）预测值的1.4倍，渔期长度则最长可达1.2倍。而拥有高种群多样性的渔业，其渔获稳定性最高可达种群更少的渔业的3.8倍，渔期长度则最长可达3倍。
4. 奇努克鲑（Oncorhynchus tshawytscha）与红大马哈鱼（O. nerka）渔业的渔获稳定性，分别可通过洄游至产卵场途中经过该渔业作业区域的种群数量与保护单元数量得到最佳解释。类似的种群多样性测度指标，同样是红大马哈鱼、驼背大马哈鱼（O. gorbuscha）、银大马哈鱼（O. kisutch）以及狗大马哈鱼（O. keta）渔业的渔期长度的重要解释变量。
5. 结论与应用。本研究提供了一项实证例证，阐明了多尺度生物多样性如何支撑大型流域内的粮食安全，并指出保护精细尺度的鲑鱼多样性将有助于提升原住民群体的粮食安全水平。环境影响评价的尺度需要与受开发活动影响的社会生态过程的尺度相匹配。本研究还表明，破坏鲑鱼栖息地的上游工程可能会削弱下游原住民渔业的粮食安全，这一结论对加拿大原住民群体以及全球范围内洄游鱼类支撑当地渔业的流域均具有启示意义。