Westgate Martin J, Crane Clare, Smith David, O'Malley Colleen, Siegrist Angelina, Florance Dan, Lang Eleanor, Crane Mason, Hingee Kassel, Scheele Ben C, Lindenmayer David B
Sustainable Farms Fenner School of Environment & Society The Australian National University Acton Australian Capital Territory Australia.
NSW Biodiversity Conservation Trust Coolac New South Wales Australia.
Ecol Evol. 2022 Mar 16;12(3):e8636. doi: 10.1002/ece3.8636. eCollection 2022 Mar.
In many farming landscapes, aquatic features, such as wetlands, creeks, and dams, provide water for stock and irrigation, while also acting as habitat for a range of plants and animals. Indeed, some species threatened by land-use change may otherwise be considerably rarer-or even suffer extinction-in the absence of these habitats. Therefore, a critical issue for the maintenance of biodiversity in agricultural landscapes is the extent to which the management of aquatic systems can promote the integration of agricultural production and biodiversity conservation. We completed a cross-sectional study in southern New South Wales (southeastern Australia) to quantify the efficacy of two concurrently implemented management practices-partial revegetation and control of livestock grazing-aimed at enhancing the vegetation structure, biodiversity value, and water quality of farm dams. We found that excluding livestock for even short periods resulted in increased vegetation cover. Relative to unenhanced dams (such as those that remained unfenced), those that had been enhanced for several years were characterized by reduced levels of turbidity, nutrients, and fecal contamination. Enhanced dams also supported increased richness and abundance of macroinvertebrates. In contrast, unenhanced control dams tended to have high abundance of a few macroinvertebrate taxa. Notably, differences remained between the macroinvertebrate assemblages of enhanced dams and nearby "natural" waterbodies that we monitored as reference sites. While the biodiversity value of semilotic, natural waterbodies in the region cannot be replicated by artificial lentic systems, we consider the extensive system of farm dams in the region to represent a novel ecosystem that may nonetheless support some native macroinvertebrates. Our results show that management interventions such as fencing and grazing control can improve water quality in farm dams, improve vegetation structure around farm dams, and support greater abundance and diversity of aquatic macroinvertebrates.
在许多农业景观中，湿地、小溪和水坝等水体特征为牲畜和灌溉提供水源，同时也是多种动植物的栖息地。事实上，一些受到土地利用变化威胁的物种，若没有这些栖息地，可能会变得更加稀少，甚至灭绝。因此，农业景观中生物多样性维护的一个关键问题是，水生系统的管理在多大程度上能够促进农业生产与生物多样性保护的融合。我们在新南威尔士州南部（澳大利亚东南部）完成了一项横断面研究，以量化两种同时实施的管理措施——部分植被恢复和牲畜放牧控制——旨在增强农场水坝的植被结构、生物多样性价值和水质的效果。我们发现，即使短时间排除牲畜也会导致植被覆盖增加。与未改善的水坝（如那些没有围栏的水坝）相比，经过数年改善的水坝浊度、营养物质和粪便污染水平较低。改善后的水坝还支持增加大型无脊椎动物的丰富度和数量。相比之下，未改善的对照水坝往往有少数几种大型无脊椎动物分类群数量较多。值得注意的是，我们作为参考地点监测的改善后的水坝与附近“天然”水体的大型无脊椎动物群落之间仍存在差异。虽然该地区半水生天然水体的生物多样性价值无法通过人工静水系统复制，但我们认为该地区广泛的农场水坝系统代表了一个新的生态系统，尽管如此，它仍可能支持一些本地大型无脊椎动物。我们的结果表明，诸如围栏和放牧控制等管理干预措施可以改善农场水坝的水质，改善农场水坝周围的植被结构，并支持水生大型无脊椎动物有更高的丰度和多样性。
