Imperata cylindrica (草)

生态 分布 管理 影响 参考数据 联系

一般影响 I. cylindrica白茅被认为是东南亚和西非潮湿的热带稀树草原最严重的杂草。世界第十大恶名昭著的杂草，它影响到使用火耕的农民。白茅十分棘手，因为它分布广，适应广泛的气候和土壤条件，竞争力强，而且能耐受许多控制方法包括焚烧(Chikoye 2003)。干燥辽阔的白茅荒地非常容易增加发生火灾的频繁和强度，破坏自然植被，以因为杀死幼芽而阻碍本土植物更替。由于白茅高的竞争能力，树植物在全是白茅的草地，会迟滞自然再生，或根本无法再生。(Jussi et al.1995) 火烧之后， I. cylindrica非常快速地从它的地下根状茎系统再生，而且可能支配先前的火耕农地长达7年之久。 I. cylindrica可以大大改变入侵地区的结构和功能。它可以侵入受干扰的生态系统，形成密集的植丛，使得其它植物几乎不可能共存(Chikoye 2003)。它取代了大量的各种原生植物，在其中觅食与居住的原生动物，也接着被取代(Chikoye 2003)。一些地面筑巢的物种也流离失所。(Johnson and Shilling Undated) 在尼泊尔，对白茅草原砍伐和焚烧的做法，不会威胁移动性好的物种（与不能容忍干扰的物种），如侏儒猪和野兔。有充分证据表明，经常火烧会影响和减少小型哺乳动物，爬虫类和无脊椎动物的相对丰度及绝对丰度。白茅对农作物的有害影响都被完整地记载。它对柚木、可可、可乐、咖啡、腰果、油棕榈、椰子、橡胶以及云南石梓的生长产生不利的影响。白茅的竞争严重降低了一年生农作物的产量，可能导致产量减少高达80%至100%。当作物生长在砍筏后没有再除草的地方时，通常会歉收。已报告木薯产量损失50至90 %。除了产量损失，白茅也增加农作物生产成本，作物受损块茎和根茎降低了市场价值，并增加多年生作物、农场和森林保护区的火灾风险。旱季经常有森林火灾，造成有机物巨大损失，从而导致土壤退化。严重受害地区的根茎株会刮伤皮肤降低种植、施肥、除草和收获的效率，导致增加劳动力需求而废耕。          地点特有的影响： Benin   农业: Imperata cylindrica is a problematic invasive agricultural weed and considered the most problematic of weeds in Benin (Vissoh et al. 2004). Ghana   农业: Imperata cylindrica is a problematic invasive agricultural weed in Ghana. The cost of weed control was 20 to 60% higher in I. cylindrica-infested fields ($71/weeding/ha) than in other fields. Eighty- six percent of fields that relied on slash-burn method of land preparation had severe I. cylindrica infestation. Infestations > 50% cover, mean density of 33 plants m-2 and shoot height range of 15–300 cm were observed on 60% of the fields. Farmers perceived average yield losses of 30–80% ha–1 due to speargrass interference, implying a national average crop loss ha-1 of $31–$84, $155–$414 and $272–$727 for maize, cassava and yam systems, respectively. Reductions in food quality due to the piercing nature of the rhizomes was also problematic (Bolfrey-Arku et al, undated). Nigeria   农业: Imperata cylindrica caused yield losses of over 70% in both maize and sorghum when the two crops were intercropped and up to 80% yield reduction in cassava (Terry et al. 1996). Florida (USA) (United States (USA))   威胁濒危物种: Imperata cylindrica is considered a threat to federally-protected species such as the 'Vulnerable (VU)' gopher tortoise (see Gopherus polyphemus) and the 'Vunerable (VU)' Camp Shelby burrowing crayfish (see Fallicambarus gordonii) based on its negative effects on habitat (Yager & Smith 2009). 改变林火机制: Imperata cylindrica was found to almost double litter biomass in ainvaded locations of Florida compared to uninvaded plots, which increases potential fuel for fires (Plack & Gottchalk 2001).