Assessing the level of compliance with alien plant regulations in a large African protected area

Regulations provide the legal basis for managing biological invasions, but assessments of their effectiveness are rare. To assess the influence of national and local regulations on alien plant species richness and composition in a large protected area (Kruger National Park; KNP; South Africa) we surveyed tourist camps and staff villages for alien ornamental plants. We compared our survey results in 2020 with a previous survey carried out between 1999 and 2003, in the context of national regulations on alien plants promulgated in 2001 and 2014. The number of alien plant species recorded in KNP has almost doubled since the first survey (231 to 438), although there has been significant species turnover (93% average replacement across all camps). Importantly, however, both the number of recorded listed and regulated alien plant species found in KNP, and their species richness per camp, have declined (by 38% overall and by 56% per camp). This suggests that regulations are effective. In contrast, the number of recorded unregulated ornamental alien species recorded has increased (by 157% overall), but this likely partly due to an increase in survey effort. Alien species regulations provide clear guidance for conservation managers, and there are promising signs of their effectiveness in directing management in KNP. However, converting alien species lists into priorities for control or regulation will continue to require risk analyses sensitive to park user needs. We advocate for better regulation effectiveness monitoring, and for such monitoring results to be interpreted based on local management needs and concerns.

法律法规为生物入侵治理提供了法律依据，但针对其实施成效的评估却较为匮乏。为评估国家及地方管控法规对南非克鲁格国家公园（Kruger National Park，简称KNP）这一大型保护区内外来植物物种丰富度与群落组成的影响，我们针对游客营地与员工村落开展了外来观赏植物调查。结合2001年与2014年颁布的国家外来植物管控法规背景，我们将2020年的调查结果与1999至2003年间开展的前期调查结果进行了对比。克鲁格国家公园记录的外来植物物种总数较首次调查时几乎翻倍（从231种增至438种），尽管各营地间存在显著的物种更替现象（平均更替率达93%）。但值得注意的是，园区内记录的列入监管名录的管控外来植物物种数量，以及各营地的物种丰富度均有所下降（整体下降38%，单营地下降56%），这表明相关法规确实起到了管控成效。与之相对，记录在案的非管控类外来观赏植物物种总数则增长了157%，但这一现象部分可能源于调查工作量的增加。外来物种管控法规为保护区管理者提供了明确的行动指南，克鲁格国家公园的管理实践中也显现出法规发挥成效的积极迹象。不过，将外来物种名录转化为管控或优先整治优先级的工作，仍需开展兼顾园区使用者需求的风险评估。我们呼吁进一步完善法规实施成效的监测体系，并基于当地管理需求与关切解读相关监测结果。