Plant Diversity and Composition Changes along an Altitudinal Gradient in the Isolated Volcano Sumaco in the Ecuadorian Amazon

Abstract

The paramo is a unique and severely threatened ecosystem scattered in the high northern Andes of South America. However, several further, extra-Andean paramos exist, of which a particular case is situated on the active volcano Sumaco, in the northwestern Amazon Basin of Ecuador. We have set an elevational gradient of 600 m (3200–3800 m a.s.l.) and sampled a total of 21 vegetation plots, using the phytosociological method. All vascular plants encountered were typified by their taxonomy, life form and phytogeographic origin. In order to determine if plots may be ensembled into vegetation units and understand what the main environmental factors shaping this pattern are, a non-metric multidimensional scaling (NMDS) analysis was performed. In addition, species turnover was quantified in order to appreciate the quantity and sort of species which are responsible for the similarity or dissimilarity between vegetation units. Therefore, a SIMPER similarity percentage analysis was conducted. We encountered 68 plant species belonging to 54 genera and 31 families, of which three are Ecuadorian endemics. The most frequent life forms were erect herbs, rosette and tussocks, whereas the least were cushions. At genus level, 44% of the Sumaco paramo flora was of tropical origin, followed by temperate (33%) and finally cosmopolitan (22%). The neotropical montane element was the most represented with 15 species, followed by the Austral-Antarctic with ten, wide temperate with another ten and cosmopolitan with seven. Regarding vegetation, four floristically distinct groups were segregated being lower gradient (3250–3500 m a.s.l.) and high altitude (3500–3800 m a.s.l.)

Botanical Collection Patterns and Conservation Categories of the Most Traded Timber Species from the Ecuadorian Amazon: The Role of Protected Areas

“…Meanwhile, with respect to the Province of Sucumbíos as reported by Guevara et al [ 38 ], it is estimated that the Cuyabeno Faunistic Reserve located in this province is the second area that reports the highest number of botanical collections in the EAR [ 14 , 19 ]. Finally, in relation to the Province of Napo, the Sumaco Biosphere Reserve and six SNAP-protected areas (Cayambre Coca National Park, Sumaco Napo-Galeras National Park, Llanganates National Park, part of the Cotopaxi National Park, Antisana Ecological Reserve, and Colonso Chalupas Biological Reserve), where various investigations have been reported focused on characterizing the floristic biodiversity present in the area, are located in this region [ 13 , 49 , 64 ]. Nonetheless, in what corresponds to the number of species, it was evidenced that the Province of Morona Santiago harbors the largest number.…”

“…Within this epicenter of biodiversity lies the Ecuadorian Amazon Region (EAR), hailed as one of the most biodiverse areas on the planet [ 11 , 12 , 13 ], especially for its high diversity of woody plants [ 14 , 15 , 16 , 17 , 18 , 19 ]. This biologically rich region is politically divided into six provinces: Sucumbíos, Orellana, Napo, Pastaza, Morona Santiago, and Zamora Chinchipe.…”

Soil Bacterial Community Along an Altitudinal Gradient in the Sumaco, a Stratovolcano in the Amazon Region

“…Samples were collected between 22 and 24 July 2016, during a 3-day survey toward the summit of the Sumaco volcano and spanned an elevation gradient between 1584 and 3809 m.a.s.l. ; thus, covering a range of vegetation transitions that included tropical, subtropical and paramo ecosystems (Lozano et al, 2020). The climbing route extended over 20 km from the town of "Pacto Sumaco" to the summit (Figure 1).…”

“…to its peak at 3732 m.a.s.l., and it is dominated by a conic structure with a basal radius of 12 km (Puerini, 2009). A heavily forested and active volcano, with the latest eruption estimated between 1933 and 1958, it is part of the Gran Sumaco Biological Reserve and Sumaco Napo-Galeras National Park (Lozano et al, 2020). Because of its unique geological origin, over 100 km to the east of the Andean arc front, the Sumaco presents unusual geochemical characteristics, with distinct alkaline lavas that are strongly saturated by silica (i.e., high alkalinity basanite to tephriphonolite), and that distinguishes it from all other active volcanoes in Ecuador (Rosenbaum et al, 2018).…”

“…Because of its unique geological origin, over 100 km to the east of the Andean arc front, the Sumaco presents unusual geochemical characteristics, with distinct alkaline lavas that are strongly saturated by silica (i.e., high alkalinity basanite to tephriphonolite), and that distinguishes it from all other active volcanoes in Ecuador (Rosenbaum et al, 2018). Presenting frequent heavy rains and challenging accessibility, it has been poorly studied in comparison to other areas of the Amazon region, with only four publications related to animal or plant diversity (Lozano et al, 2020). Its remoteness and inaccessibility have also contributed to preserving its forest.…”