The role of edaphic factors on plant species richness and diversity along altitudinal gradients in the Brazilian semi-arid region

2020 ◽  
pp. 1-14
Author(s):  
Maiara B. Ramos ◽  
Fabricio C. Diniz ◽  
Humberto A. de Almeida ◽  
Gilbevan R. de Almeida ◽  
Anderson S. Pinto ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Plant Community ◽  
Arid Region ◽  
Plant Species Richness ◽  
Edaphic Factors ◽  
Altitudinal Gradients ◽  
Semi Arid Region ◽  
Semi Arid

Abstract Unlike well-known global patterns of plant species richness along altitudinal gradients, in the mountainous areas of the Brazilian Caatinga, species richness and diversity reach their maxima near mountain tops. The causes of this unusual pattern are not well understood, and in particular the role of edaphic factors on plant community assembly along these gradients has not been investigated. Our goal was to assess the role of edaphic factors (fertility and soil texture) on plant community composition and structure on two mountains of the Brazilian semi-arid region. In 71 plots (Bodocongó site, twenty-one 200-m2 plots, 401–680 m asl; Arara site, fifty 100-m2 plots, 487–660 m asl) we recorded 3114 individuals representing 61 plant species; in addition, at each plot we collected composite soil samples from 0–20 cm depth. Significant altitude-related changes were observed both for community structure and composition, and edaphic variables. A canonical correspondence analysis allowed the distinction of two groups of plots according to species abundances, indicating a preferential habitat distribution of species depending both on altitude and soil variables. Although soil fertility was lowest at the highest altitudes, these areas had high richness and diversity. Conversely, the more fertile foothills were characterized by the dominance of generalist pioneer species. Despite the relatively short altitudinal range that characterizes the studied mountains, this study elucidates the role of edaphic factors on the floristic composition and species richness patterns on the mountains of the Brazilian semi-arid region.

scholarly journals O PAPEL DA JUVENTUDE CAMPONESA NA CONSTRUÇÃO DE ECONOMIAS DE RESISTÊNCIA NO SEMIÁRIDO NORDESTINO/The role of peasant youth in the construction of resistance economies in the northeastern semi-arid region

REVISTA NERA ◽  
2017 ◽  
pp. 144-156
Author(s):  
Gabriel Troilo ◽  
Maria Nalva Rodrigues Araújo
Keyword(s):  
Arid Region ◽  
Semi Arid Region ◽  
Semi Arid

O objetivo do presente trabalho é apresentar as reflexões promovidas pelas organizações sociais do campo e por pesquisadores da questão agrária sobre a forma como as comunidades camponesas do semiárido nordestino se articulam para garantir as condições de produção e subsistência em meio à lógica de livre mercado capitalista, destacando o papel da juventude do campo neste processo. Para tanto foram analisadas as experiências de produção e mercado das comunidades camponesas do semiárido baiano, levando em conta a dinâmica econômica, os enfrentamentos, potencialidades e estratégias de resistência das mesmas frente o avanço do mercado capitalista na atualidade. As ações da juventude do campo na estruturação de economias de resistência, seja pelo associativismo e cooperativismo rural, pela formação de mercados camponeses e ocupação do mercado capitalista tem possibilitado a viabilidade da produção camponesa frente às pressões do modelo de produção agrícola dominante. Tais estratégias tem gerado importantes avanços para o campo no semiárido nordestino, e demonstram os resultados da luta política da juventude do campo pela perpetuação do modo de vida camponês e pela construção da soberania alimentar e territorial das comunidades sertanejas. 

The Effects of Expansive Shrubs on Plant Species Richness and Soils in Semi‐arid Communal Lands, South Africa

2017 ◽  
Vol 28 (7) ◽  
pp. 2191-2206 ◽  
Author(s):  
Craig Sholto‐Douglas ◽  
Charlie M. Shackleton ◽  
Sheunesu Ruwanza ◽  
Tony Dold
Keyword(s):  
South Africa ◽  
Species Richness ◽  
Plant Species ◽  
Plant Species Richness ◽  
Communal Lands ◽  
Semi Arid

scholarly journals The invasive herb Lupinus polyphyllus can reduce plant species richness independently of local invasion age

2021 ◽  
Author(s):  
Marju Prass ◽  
Satu Ramula ◽  
Miia Jauni ◽  
Heikki Setälä ◽  
D. Johan Kotze
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Plant Community ◽  
Plant Communities ◽  
Vascular Plant ◽  
Plant Species Richness ◽  
Ecological Impacts ◽  
Plant Community Composition ◽  
Lupinus Polyphyllus ◽  
Local Invasion

AbstractThe ecological impacts of invasive species may change or accumulate with time since local invasion, potentially inducing further changes in communities and the abiotic environment. Yet, time since invasion is rarely considered when investigating the ecological impacts of invasive non-native species. To examine the effect of time since invasion on the ecological impacts of Lupinus polyphyllus, a perennial nitrogen-fixing herb, we surveyed vascular plant communities in the presence and absence of L. polyphyllus in young, intermediate, and old semi-natural grassland sites (ca. 5, 10, 15 years representing both time since lupine invasion and plant community age). We analyzed vascular plant community composition, vascular plant species richness, and the cover of various ecological plant groups and L. polyphyllus. In contrast to our hypotheses, we found no change in the mean cover of L. polyphyllus (about 35%) with time since local invasion, and an ordination did not suggest marked changes in plant community composition. L. polyphyllus was associated with lower species richness in invaded plant communities but this effect did not change with time since invasion. Invaded plant communities were also associated with lower occurrence of generalist, oligotrophic (low-nutrient-adapted) and copiotrophic (nutrient-demanding) species but no temporal dynamics were detected. We conclude that even the intermediate cover of L. polyphyllus can reduce plant species richness, but the ecological impact caused by this invader might not dramatically change or accumulate with time since invasion.

scholarly journals The mid-domain effect of species diversity of mountainous plants is determined by community life form and family flora in a temperate semi-arid region of China

2018 ◽  
Author(s):  
Xu Manhou ◽  
Wen Jing
Keyword(s):  
Species Diversity ◽  
Arid Region ◽  
Life Form ◽  
Community Life ◽  
The Loess Plateau ◽  
Altitudinal Gradients ◽  
The Family ◽  
Plant Level ◽  
Semi Arid Region ◽  
Semi Arid

The mid-domain effect (MDE) is a vital hypothesis to explain altitudinal patterns of species diversity of mountainous plants with different gradients, but it is bounded in terms of its application at the plant level. To verify the MDE hypothesis, we chose a typical mountain with obvious elevation gradients and considerable plant coverage as a study area in the east of the Loess Plateau and partitioned various elevation belts across this mountain. Through measuring the species diversity of arbor, shrub and herb communities in forest ecosystems, we explored altitudinal patterns of species diversity of mountainous plants with different gradients. We determined that the family numbers of the herb and shrub communities, as well as the species diversity of the arbor community, reached their maximums at intermediate elevations. The family numbers of the herb and shrub communities presented unimodal patterns across altitudinal gradients, and the highest values occurred at intermediate elevations. The family number of the arbor community showed a monotonic decreasing pattern, and the importance values of dominant families in the shrub and arbor communities presented unimodal patterns, but the lowest values occurred at intermediate elevations. The species diversity of the herb, shrub and arbor communities conformed to unimodal change patterns following altitudinal gradients, but the greatest diversity occurred at high, low and intermediate elevations, respectively. At higher elevations, weeds and grasses grew well, whereas sedges grew well at lower elevations. With respect to the importance values of different arbor life forms, their responses to altitudinal gradients indicated a certain variation pattern, which was greater for evergreen coniferous arbor species than for deciduous coniferous arbor species and deciduous broad-leaved arbor species. It is concluded that the MDE hypothesis of species diversity for mountainous plants is influenced greatly by the community life form and family flora at the plant level in a temperate semi-arid region of the Loess Plateau, China. This conclusion tests and modifies the MDE hypothesis and can be valuable for fueling prediction of biodiversity models and for the comparison with similar studies in different regions.

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