Reply to Hulme et al.: Cover of non-native species is too low to adversely affect native plant diversity at a national scale.
Reply to Hulme et al.: Cover of non-native species is too low to adversely affect native plant diversity at a national scale.
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回复 Hulme 等人：非本地物种的覆盖率太低，不会对全国范围内的本地植物多样性产生不利影响。
DOI：
10.1073/pnas.1507966112
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发表时间：
2015
影响因子：
11.1
通讯作者：
Thomas CD
中科院分区：
文献类型：
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作者：
Thomas CD
Hulme等人(1)质疑我们关于非本土植物对英国植物多样性影响的研究结论。我们清楚地指出，“一些非本地物种在某些地方变得普遍，从而改变了当地的植物群，可能对保护产生当地的影响”（2），这似乎是Hulme等人的观点。这是我们的主要观点，但我们发现“没有证据表明非本地物种在全国范围内推动了这种变化，或者它们比本地物种更能做到这一点”。如Hulme等人所强调的，可能需要管理部门从特定地点清除非本地植物物种。（一）.然而，我们的农村调查（CS）分析表明，本地物种覆盖率的增加几乎比非本地物种覆盖率的增加大一个数量级：我们应该根据物种的影响而不是它们的起源采取行动（3），特别是，我们应该在感受到这些影响的地方这样做。例如，在英国，保持高保护价值的低地白垩和石灰岩草原需要控制本地树木和灌木物种（如山楂、白蜡树、紫杉）和丛生草（如短柄草），即使非本地树木也需要从某些地方移走（如从数量有限的主要沿海地点移走霍尔姆橡树）。问题在于，这些物种丰富的草原是人类创造的斜长石，除非定期放牧或砍伐，否则自然会成为林地。在这种情况下，变化的驱动力是土地管理，而不是外来物种。如果自然资源保护主义者希望保持这种文化植被，就需要独立于国家的树木砍伐。我们同意Hulme等人的观点。s（1）声明“CS只记录了英国10%的非本土植物群”，并且“只有4个[合法列出和受威胁的]物种被记录在CS中，它们出现在几个样方中”。我们的观点正是如此。大多数非本土物种，包括那些被正式归类为入侵物种的物种，都太罕见了，不会对全国平均的植物多样性产生负面影响。因此，他们在英国的存在增加了国家的总花卉多样性。CS采样最广泛分布的栖息地类型在农村，因此，它是相关的，以得出全国范围的结论。我们预计，我们的广泛结论也将保持（在一个
Hulme et al.(1) question the conclusions of our research on the impact of non-native plants on British plant diversity (2). We clearly state that “some non-native species become common in some locations, and thereby alter the local flora, and there may be local implications for conservation”(2), which seems to be Hulme et al.’s (1) main point, but we found “no evidence that nonnative species drive such changes at a national scale or that they do so any more than native species”(2). Management may be required to remove non-native plant species from particular localities, as highlighted by Hulme et al.(1). However, our Countryside Survey (CS) analysis shows that increases in cover by native species were nearly an orderof-magnitude greater than cover increases by non-native species: we should take action based on the impacts of species rather than their origins (3), and specifically, we should do so in locations where those impacts are felt. For example, the maintenance of highconservation value lowland chalk and limestone grasslands in Britain requires the control of native tree and shrub species (eg, hawthorn, ash, yew) and tussock-forming grasses (eg, Brachypodium), even though non-native trees also need removing from some localities (eg, holm oaks from a limited number of mainly coastal sites). The issue is that these species-rich grasslands are humancreated plagioclimaxes, which naturally succeed to woodland unless regularly grazed or cut. The driver of change in this case is land management, not foreign species. Nationalityindependent tree removal is required if conservationists wish to maintain this cultural vegetation.Data speak louder than words. We are in agreement with Hulme et al.’s (1) statement that the “CS records only about 10% of the non-native flora of Britain” and that just “four of these [legally listed and threatening] species are recorded in the CS, and they occur in few quadrats.” Our point exactly. Most non-native species, including those that are officially classed as invasive, are far too rare to impinge negatively on plant diversity, averaged across the country. As such, their presence in Britain adds to the nation’s total floral diversity. The CS samples the most widely distributed types of habitat in the countryside, and hence it is relevant to draw national-scale conclusions. We expect that our broad conclusions will also hold (at a