Risco de deficiência hídrica decendial na metade sul do Estado do Rio Grande do Sul

Leivas, J. F.; Berlato, Moacir Antônio; Fontana, Denise Cybis

doi:10.1590/s1415-43662006000200022

Cited by 25 publications

(17 citation statements)

References 1 publication

(1 reference statement)

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“…Daily data of temperature and 225 MATURATION OF Eugenia pyriformis SEEDS rainfall (mm) were collected between flowering and harvest and were used to calculate respectively: the growing degree-day (GDD, °C day), according to the equations proposed by Villa Nova et al (1972), considering 10°C as base temperature (Pedro Junior et al 1977); and accumulated rainfall (mm). Sequential water balance was also calculated with rainfall data using the model proposed by Thornthwaite and Mather (1955), in descending scale level with available water capacity (AWC) of 125 mm (Leivas et al 2006, Rolim et al 2007.…”

Section: Methodsmentioning

confidence: 99%

Maturation of Eugenia pyriformis seeds under different hydric and thermal conditions

Lamarca

Prataviera

Borges³

et al. 2013

An. Acad. Bras. Ciênc.

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This study aims to analyze the maturation and dispersal of Eugenia pyriformis Cambess. seeds produced in different years, and the influence of variation in thermal and hydric environment on seed physical and physiological characteristics at dispersal. Fruits at different developmental stages were harvested in the city of São Paulo between 2003 and 2010, as well as in the cities of Campinas and Lavras, in 2009 and 2010 and analyzed for size and color. The seeds were extracted from the fruits and their dry mass, water content, germination and vigor were assessed. Results showed that seed maturation is unsynchronized to the maturation of the fruit, taking 45 days on average (430 growing degree-days), longer in rainy times or lower temperatures. Seeds with higher physiological quality were produced in rainy years and when the temperature range was larger. We concluded therefore that hydric and thermal environmental variations during development influence the maturation of Eugenia pyriformis seeds and are able to determine the formation cycle and the final seed quality.

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Section: Methodsmentioning

confidence: 99%

Maturation of Eugenia pyriformis seeds under different hydric and thermal conditions

Lamarca

Prataviera

Borges³

et al. 2013

An. Acad. Bras. Ciênc.

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“…Natural grasslands in the area are historically used as the main forage source for livestock production, as in most of the preserved natural grassland ecosystems in the region (Nabinger et al 2009). According to the Köppen climate classifi cation system, the climate in the study area is type Cfa, theoretically with no dry season, although there is a high probability of soil water defi cit during the peak of summer (Leivas et al 2006). Th e soil in the sampling area is a Lithic Ustorthents (Neossolo Litólico Eutrófi co by the Brazilian Soil Classifi cation System, Pedregal mapping unit; EMBRAPA 1999).…”

Section: Methodsmentioning

confidence: 99%

Floristic and vegetation structure of a grassland plant community on shallow basalt in southern Brazil

et al. 2013

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Few studies have adequately described the fl oristic and structural features of natural grasslands associated with shallow basalt soils in southern Brazil. Th is study was carried out on natural grazing land used for livestock production in the municipality of Santana do Livramento, in the Campanha region of the state of Rio Grande do Sul, Brazil. Th e aim of the study was to describe the fl oristic and structural diversity of the area. Th e fl oristic list obtained comprises 229 plant taxa from 40 botanical families, with a predominance of the families Poaceae (62), Asteraceae (28), Fabaceae (16) and Cyperaceae (12). Th e estimated diversity and evenness in the community were 3.00 and 0.874, respectively. Bare soil and rock outcrops accounted for 19.3% of the area, resulting in limited forage availability. Multivariate analysis revealed two well-defi ned groups among the sampling units. One group showed a high degree of internal aggregation, associated with deep soils, and was characterized by the presence of tussocks, whereas the other was less aggregate and was characterized by prostrate species growing on shallow soil. Ordination analysis indicated a gradient of moisture and of soil depth in the study area, resulting in diff erent vegetation patterns. Th ese patterns were analogous to the vegetation physiognomies described for Uruguayan grasslands. Overall, the grassland community studied is similar to others found throughout southern Brazil, although it harbors more winter forage species. In addition, the rare grass Paspalum indecorum Mez is locally dominant in some patches, behaving similarly to P. notatum Fl., a widespread grass that dominates extensive grassland areas in southern Brazil.

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“…), in the last few decades some prolonged periods of water deficit have occurred, mainly in the southwest of Rio Grande do Sul (Leivas et al. ; Albuquerque & Mendes ). Thus, native species might have been adversely affected, promoting invasion success by opening gaps for invasive species establishment.…”

Section: Discussionmentioning

confidence: 99%

Landscape structure and climate affect plant invasion in subtropical grasslands

Guido

Vélez‐Martin

Overbeck

et al. 2016

Applied Vegetation Science

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Question: How do climate and landscape structure affect plant invasion process in south Brazilian natural grasslands?Location: Natural grasslands across Rio Grande do Sul state, southern Brazil.Methods: We selected 20 plots (2 km 9 2 km each), situated in ten different grassland types in southern Brazil. In each grassland type, one plot was located in a region with remnant grassland cover <30% (not conserved landscapes) and another in a region with remnant grassland cover >60% (conserved landscapes), in a paired design. In each plot, we surveyed the presence and cover of the four most important invasive species of grasslands in Rio Grande do Sul (Cynodon dactylon, Eragrostis plana, Senecio madagascariensis and Ulex europaeus). We used 12 variables related to climate and landscape structure (i.e. composition and configuration) for testing causal models of plant invasion using Akaike's information criterion for path analyses.Results: Empirical evidence on how climatic conditions and landscape structure can cause plant invasion in subtropical grasslands was provided through six causal models validated with path analysis. The models indicated that increased water deficit, higher density of roads and losses in natural grassland cover caused an increment of invasive plant cover. Further, invasion differed between plots located in conserved vs not conserved landscapes, resulting in not conserved grasslands having a higher level of invasion. E. plana, a perennial grass from South Africa, was the most important invasive species in the grasslands, in terms of frequency and cover.Conclusions: Our results identified the general conditions that promote successful population growth of invasive plants in subtropical grasslands: water deficit, road density and land use, highlighting the effects of climate, landscape structure and human activity in the level of invasion across grassland types.

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Risco de deficiência hídrica decendial na metade sul do Estado do Rio Grande do Sul

Cited by 25 publications

References 1 publication

Maturation of Eugenia pyriformis seeds under different hydric and thermal conditions

Maturation of Eugenia pyriformis seeds under different hydric and thermal conditions

Floristic and vegetation structure of a grassland plant community on shallow basalt in southern Brazil

Landscape structure and climate affect plant invasion in subtropical grasslands

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