Haugen Hanne, Dervo Børre K, Østbye Kjartan, Heggenes Jan, Devineau Olivier, Linløkken Arne
Department of Forestry and Wildlife Management Inland Norway University of Applied Sciences Hamar Norway.
Norwegian Institute for Nature Research (NINA) Oslo Norway.
Evol Appl. 2023 Dec 20;17(1):e13633. doi: 10.1111/eva.13633. eCollection 2024 Jan.
Genetic diversity is a key part of biodiversity, threatened by human activities that lead to loss of gene flow and reduction of effective population sizes. Gene flow is a result of both landscape connectivity and demographic processes determining the number of dispersing individuals in space and time. Thus, the effect of human impact on processes determining the level of genetic diversity must be interpreted in the context of basic ecological conditions affecting survival and recruitment. When the intensity of human impact and habitat suitability correlate, the effect on genetic diversity and gene flow may be challenging to predict. We compared genetic diversity, gene flow and landscape resistance in two contrasting landscapes in Norway for the pond-breeding amphibian : a highly human-impacted, agricultural landscape with ecologically productive habitats, and a forested landscape with less productive habitats and lower levels of human impact. Our results show that genetic diversity was higher and gene flow lower within the forested landscape. Microclimatic moisture conditions and vegetation cover were important determinants of landscape resistance to gene flow within both landscapes. There were indications that landscape resistance was increased by minor roads in the forested landscape, which was not the case for the agricultural landscape, suggesting a higher vulnerability to human interference within the landscape matrix for the populations in less productive habitats. Our findings suggest that the effect of human impact on genetic diversity may not be straightforward but modulated by the ecological conditions underlying local demographic processes. Populations within both landscapes seem to be vulnerable to loss of genetic diversity, but due to different mechanisms. This has implications for the choice of relevant management actions, that is, increasing population stability may be more relevant within an agricultural landscape still permeable for dispersal, while conserving dispersal corridors may be more appropriate in the forested landscape, to avoid isolation and increased genetic drift.
遗传多样性是生物多样性的关键组成部分，受到导致基因流丧失和有效种群规模减小的人类活动的威胁。基因流是景观连通性和人口过程的结果，这些过程决定了在空间和时间上扩散个体的数量。因此，必须在影响生存和补充的基本生态条件的背景下，解释人类影响对决定遗传多样性水平的过程的作用。当人类影响的强度与栖息地适宜性相关时，对遗传多样性和基因流的影响可能难以预测。我们比较了挪威两种截然不同景观中池塘繁殖两栖动物的遗传多样性、基因流和景观抗性：一种是受人类高度影响的农业景观，具有生态生产力高的栖息地；另一种是森林景观，栖息地生产力较低，人类影响水平较低。我们的结果表明，森林景观中的遗传多样性较高，基因流较低。微气候湿度条件和植被覆盖是两种景观中基因流景观抗性的重要决定因素。有迹象表明，森林景观中的小路增加了景观抗性，而农业景观则不然，这表明生产力较低栖息地中的种群对景观基质中人类干扰的脆弱性更高。我们的研究结果表明，人类影响对遗传多样性的作用可能并不直接，而是受到当地人口过程背后生态条件的调节。两种景观中的种群似乎都容易丧失遗传多样性，但原因不同。这对相关管理行动的选择具有启示意义，即在仍然允许扩散的农业景观中，提高种群稳定性可能更相关，而在森林景观中，保护扩散走廊可能更合适，以避免隔离和遗传漂变增加。
