Open habitats such as grasslands occupy < 5% of the Amazon and are currently grouped under the broad term Amazonian savanna, covering an area of c. 267 000 km², mostly in Brazil and Bolivia. These habitats are found isolated within an extensive rainforest matrix, having a distinct flora from the latter. The lower Amazon River is home to several patches of savanna that occupy both south and north banks of the river, in Santarém, Alenquer and Monte Alegre. Although having an abundance of herbaceous plants, most studies on these open areas focus only on tree species, ignoring the relevant non-woody component of the vegetation. Our objectives were to provide new surveys of seed plants for two Amazonian savanna sites and to take the opportunity to revisit the biogeographical links between Amazonian savanna, Amazonian canga vegetation and the central Brazilian cerrado (CBC) and caatinga, analysing woody and herbaceous plants. We created a floristic database that includes sites of Amazonian savannas, including campinarana, coastal scrub (restinga), CBC and Amazonian campos rupestres (on canga or other substrate). We compared those sites using multivariate analyses to find out the degree of floristic resemblance between sites. We prepared a new list of 406 species of seed plants [336 in Parque Estadual de Monte Alegre (PEMA) and 117 in Serra do Itauajuri (SI)], including 23 new records for the state of Pará and some putative new species for science. The Amazonian savannas form three loosely arranged groups, whereas the Amazonian canga formed a cohesive assemblage. Both groups were contrasted against cerrado and caatinga sites and had a distinctive flora from both. Sites from north-western Pará (Alter do Chão, PEMA and SI) were grouped with their northern counterparts in Roraima. An improved representation of the flora of these sites is provided, with more insight into the relationship between the Amazonian savanna sites and other vegetation types. It is worrying that recent changes of the Brazilian legislation place open environments, such as PEMA, in the path of vulnerability to disturbance and destruction.

中文翻译：

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亚马逊森林之外：亚马逊热带草原的生物地理和植物关系

诸如草原之类的开放栖息地占亚马逊地区的5％以下，目前被归类为广义的亚马逊大草原，覆盖面积c。267 000千米²，主要在巴西和玻利维亚。发现这些生境被隔离在广阔的热带雨林基质中，具有与后者不同的植物区系。亚马逊河下游是圣塔伦，阿伦克尔和阿雷格里山的几片稀树草原的所在地，这些稀树草原占据了该河的南北两岸。尽管有大量的草本植物，但大多数对这些空旷地区的研究只关注树木，而忽略了植被的相关非木质成分。我们的目标是为两个亚马逊大草原地区的种子植物提供新的调查，并借此机会重新审视亚马逊大草原，亚马逊加拿大高加索植被与巴西中部Cerrado（CBC）和caatinga之间的生物地理联系，分析木本和草本植物。我们创建了一个植物数据库，其中包括亚马逊热带草原的站点，包括桔梗，沿海灌木丛（restinga），CBC和亚马逊桔梗（在加贺或其他基质上）。我们使用多变量分析比较了这些位点，以找出位点之间的植物区系相似程度。我们准备了406种种子植物的新清单[蒙特阿雷格里公园（336），伊塔阿祖里（SI）的117]，包括帕拉州的23项新记录和一些可能的科学新物种。亚马孙热带稀树草原形成三个松散排列的群体，而亚马孙甘加羚羊则形成一个凝聚的组合。两组都与塞拉多和卡廷加遗址形成对比，两者都有独特的菌群。来自西北帕拉（Alter doChão，PEMA和SI）的遗址与北部的Roraima遗址归为一组。提供了这些地点植物区系的改进表示，并进一步了解了亚马逊热带稀树草原地点与其他植被类型之间的关系。令人担忧的是，巴西立法的最新变化将开放环境（如PEMA）置于容易受到干扰和破坏的道路上。