School of Environmental Sciences, University of Liverpool, Liverpool, UK.
School of Environmental Sciences, University of Liverpool, Liverpool, UK.
J Environ Manage. 2018 Feb 1;207:1-9. doi: 10.1016/j.jenvman.2017.11.013. Epub 2017 Nov 14.
It is well known that soils are influenced by the plant species that grow in them. Here we consider the effects of management-induced changes to plant communities and their soils during restoration within a 20-year manipulative experiment where the aim was to change a late-successional community dominated by the weed, Pteridium aquilinum, to an earlier-successional grass-heath one. The ecological restoration treatments altered the above- and below-ground components of the community substantially. Untreated plots maintained a dense Pteridium cover with little understory vegetation, cutting treatments produce significant reductions of Pteridium, whereas herbicide (asulam) produced significant immediate reductions in Pteridium but regressed towards the untreated plots within 10 years. Thereafter, all asulam-treated plots were re-treated in year 11, and then were spot-sprayed annually. Both cutting and asulam treatments reduced frond density to almost zero and resulted in a grass-heath vegetation. There was also a massive change in biomass distribution, untreated plots had a large above-ground biomass/necromass that was much reduced where Pteridium was controlled. Below-ground in treated plots, there was a replacement of the substantive Pteridium rhizome mass with a much greater root mass of other species. The combined effects of Pteridium-control and restoration treatment, reduced soil total C and N as and available P concentrations, but increased soil pH and available N. Soil biological activity was also affected with a reduction in soil N mineralization rate, but an increased soil-root respiration. Multivariate analysis showed a clear trend along a pH/organic matter gradient, with movement along it correlated to management intensity from the untreated plots with low pH/high organic matter and treated plots with to a higher pH/lower organic matter in the sequence asulam treatment, cut once per year to cut twice per year. The role that these changed soil conditions might have in restricting Pteridium recovery are discussed.
众所周知，土壤会受到生长其中的植物物种的影响。在这里，我们考虑了在一项为期 20 年的操纵实验中，管理诱导的植物群落及其土壤变化的影响，该实验的目的是将一个由杂草 Pteridium aquilinum 主导的晚生演替群落改变为一个更早的草本-石南灌丛群落。生态恢复处理极大地改变了群落的地上和地下部分。未处理的样地保持了茂密的 Pteridium 覆盖，几乎没有林下植被，刈割处理显著减少了 Pteridium，但在 10 年内，除草剂（asulam）处理则显著地立即减少了 Pteridium，但在 10 年内回归到未处理的样地。此后，所有的 asulam 处理样地在第 11 年再次进行处理，然后每年进行点状喷雾。刈割和 asulam 处理都将叶片密度降低到几乎为零，并导致草本-石南植被。生物量分布也发生了巨大变化，未处理的样地地上生物量/枯落物量很大，而 Pteridium 得到控制的样地则大大减少。在处理样地的地下，大量的 Pteridium 根茎质量被其他物种的更大根质量所取代。Pteridium 控制和恢复处理的综合影响降低了土壤总 C 和 N 以及有效 P 浓度，但增加了土壤 pH 和有效 N。土壤生物活性也受到影响，土壤氮矿化率降低，但土壤-根呼吸增加。多元分析显示，沿着 pH/有机质梯度有一个明显的趋势，沿着这个梯度移动与未处理样地的管理强度相关，未处理样地的 pH 低/有机质高，而处理样地的 pH 高/有机质低，依次为 asulam 处理、每年刈割一次到每年刈割两次。讨论了这些变化的土壤条件可能对限制 Pteridium 恢复的作用。
