Vegetação campestre do sul do Brasil: dinâmica de espécies à exclusão do gado

Boldrini, Ilsi Iob; Eggers, Lilian

doi:10.1590/s0102-33061996000100004

Cited by 47 publications

(38 citation statements)

References 14 publications

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“…With the exclusion of grazing, the vegetation loses the agent responsible for maintaining its initial condition and tends to change (BOLDRINI et al, 1996), which is in accordance to the variations evidenced in our study.…”

Section: Soil-plant Relationshipsupporting

confidence: 91%

Grazing Changes the Soil-Plant Relationship in the Tree-Regeneration Stratum in the Pampa of Souhtern Brazil

Redin

Longhi

Reichert

et al. 2017

CERNE

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Despite being prominent in flora, the region of the Parque Estadual do Espinilho located in the Pampas of southern Brazil, where dense herbaceous stratum and isolated trees make this region suitable for livestock farming, has received little attention. The objective of the study was to analyze floristic and edaphic changes imposed by livestock farming in two areas of the park, the first under livestock grazing and the second protected from grazing (livestock-excluded) for five years. We evaluated soil physical properties of and the herbaceous aboveground biomass in order to investigate relationships with key regenerating tree species. A sampling unit of 2ha was installed in both areas, each composed of 200 subunits. Inventory of regenerating trees and herbaceous aboveground biomass, soil sampling, and soil penetration resistance tests were done in 50 subunits. The results, which were evaluated by Student's t-test, exhibited variations between the two areas in regards to floristic and environmental factors. The abundance of the P. affinis and V. caven species and the variables of soil penetration resistance, soil bulk density, gravimetric moisture and herbaceous aboveground biomass differ significantly between the two areas. Principal coordinates analysis (PCoA) allows to infer that variables such as soil bulk density, penetration resistance and the abundance of V. caven species exhibit higher values in the area under gazing, while gravimetric moisture, aboveground biomass and abundance of P. affinis are higher in the area under livestock-excluded, showing that significant changes occur over just five years of livestock-excluded from the area. O PASTEJO ALTERA A RELAÇÃO SOLO-PLANTA NO ESTRATO REGENERANTE ARBÓREO NO PAMPA GAÚCHO RESUMO:A região do Parque Estadual do Espinilho, inserida nos domínios fitogeográficos da Savana Estépica Parque, ainda é pouco estudada, apesar de ser destaque na flora sulina. Características como denso estrato herbáceo e árvores isoladas configuram-na como propícia à pecuária. Objetivou-se analisar alterações florísticas e edáficas impostas pelo pastejo em duas áreas do Parque, a primeira sob pastejo e a segunda protegida por cinco anos. Foram avaliadas propriedades físicas do solo e biomassa aérea do estrato herbáceo, visando investigar relações com as principais espécies arbóreas regenerantes. Foi instalada uma unidade amostral de 2ha em ambas as áreas, compostas por 200 subunidades cada. O inventário do estrato regenerante, as coletas para análises de solo, biomassa aérea do estrato herbáceo e testes de resistência do solo à penetração foram realizados em 50 subunidades. Os resultados avaliados pelo teste t de Student demonstram que há variações entre florística e fatores ambientais aferidos entre as duas áreas. A abundância das espécies P. affinis e V. caven e as variáveis resistência do solo à penetração, densidade do solo, umidade gravimétrica e biomassa aérea do estrato herbáceo diferem significativamente. A análise exploratória de ordenação (PCoA) permite inferir que v...

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Section: Soil-plant Relationshipsupporting

confidence: 91%

Grazing Changes the Soil-Plant Relationship in the Tree-Regeneration Stratum in the Pampa of Souhtern Brazil

Redin

Longhi

Reichert

et al. 2017

CERNE

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“…Não há, ainda, estudos que indiquem quantos anos de exclusão de pastejo seriam necessários, para que o processo de restauração permitisse que as áreas fossem novamente utilizadas com atividade pecuária, mas pelo que se conhece a respeito da dinâmica de vegetação com exclusão de pastejo em áreas campestres não-degradadas (Boldrini & Eggers, 1996;Quadros & Pillar, 2001;Overbeck et al, 2007), acredita-se que, com o tempo, a vegetação campestre evoluiria naturalmente para um predomínio de arbustos e, a depender da disponibilidade de fontes de propágulos, espécies arbóreas. A utilização do ajuste de lotação (Boldrini, 1993;Soares et al, 2005), de forma a se ter oferta adequada de forragem por unidade animal, pode ser uma alternativa a ser utilizada em conjunto com exclusões temporárias.…”

Section: Resultsunclassified

Vegetação campestre de areais do Sudoeste do Rio Grande do Sul sob pastejo e com exclusão do pastejo

Trindade

Quadros

Pillar

2008

Pesq. agropec. bras.

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Resumo -O objetivo deste trabalho foi caracterizar os efeitos de dois manejos do pastejo, sobre a vegetação natural do entorno de areais, da região Sudeste do Rio Grande do Sul. Foram estudadas 41 parcelas de comunidades de 4,5x9 m: 30 sob pastejo e 11 em areais excluídos do pastejo. A composição da vegetação foi analisada por meio de inventário das espécies de plantas vasculares, presentes nas parcelas, e por meio de estimativa da abundância/ cobertura de cada espécie e substrato exposto. Foram identificadas 53 espécies, distribuídas em 43 gêneros e 16 famílias. Apareceram em mais de 50% das comunidades estudadas: Axonopus pressus, Elionurus sp., Schizachyrium microstachyum, Bulbostylis sp., Senecio sp., Baccharis coridifolia, Psidium sp., Cardionema ramosissima e Borreria verticillata. Andropogon lateralis esteve restrita ao município de Alegrete, próximo ao rio Ibicuí. A exclusão do pastejo aumenta a cobertura vegetal e a diversidade em comparação a comunidades pastejadas. Vegetação natural sob pastejo é mais suscetível ao processo de arenização. Areais manejados sob pastejo apresentam mais substrato exposto e Elionurus sp., Axonopus pressus e Cardionema ramosissima.Termos para indexação: Axonopus pressus, Butia paraguayensis, áreas degradadas, campo nativo, restauração. Grassland vegetation of sandy patches of Rio Grande do Sul under grazing and exclosureAbstract -The objective of this study was to characterize the effects of two grazing management on the natural vegetation, in the edge of sandy patches of Southwest of Rio Grande do Sul State, Brazil. Forty-one community areas of 4.5x9 m, were evaluated: 30 under grazing, and 11 under grazing exclusion. The vegetation composition in each community area was described by visually estimated cover-abundances of vascular plant species and bare-ground. Fifty-three 53 different taxa were identified from 43 genera and 16 families. Axonopus pressus, Elionurus sp., Schizachyrium microstachyum, Bulbostylis sp., Senecio sp., Baccharis coridifolia, Psidium sp., Cardionema ramosissima and Borreria verticillata were present in more than 50% of the communities. Andropogon lateralis was restricted to communities in Alegrete near to the Ibicuí River. Exclosures increase vegetation coverage and diversity, when compared to grazed ones. Natural vegetation under grazing is more susceptible to sandy patch process. Sandy patches under grazing have higher bareground and Elionurus sp., Axonopus pressus and Cardionema ramosissima.

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“…The campos rupestres of Brazil are an example of such a system where shallow soils and shallow‐rooted plants are very sensitive to trampling (Kolbek & Alves, ). In other grasslands, typically with higher soil fertility, domestic livestock may be important to the maintenance of biodiversity by functioning as a surrogate for fire or by mimicking the effects of native herbivores (Boldrini & Eggers, ; Blanco et al ., ; Overbeck et al ., ). Indeed, literature on grasslands that are resilient to moderate cattle grazing (Mcintyre, Heard & Martin, ; Fig.…”

Section: Resiliencementioning

confidence: 99%

Resilience and restoration of tropical and subtropical grasslands, savannas, and grassy woodlands

et al. 2018

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Despite growing recognition of the conservation values of grassy biomes, our understanding of how to maintain and restore biodiverse tropical grasslands (including savannas and open‐canopy grassy woodlands) remains limited. To incorporate grasslands into large‐scale restoration efforts, we synthesised existing ecological knowledge of tropical grassland resilience and approaches to plant community restoration. Tropical grassland plant communities are resilient to, and often dependent on, the endogenous disturbances with which they evolved – frequent fires and native megafaunal herbivory. In stark contrast, tropical grasslands are extremely vulnerable to human‐caused exogenous disturbances, particularly those that alter soils and destroy belowground biomass (e.g. tillage agriculture, surface mining); tropical grassland restoration after severe soil disturbances is expensive and rarely achieves management targets. Where grasslands have been degraded by altered disturbance regimes (e.g. fire exclusion), exotic plant invasions, or afforestation, restoration efforts can recreate vegetation structure (i.e. historical tree density and herbaceous ground cover), but species‐diverse plant communities, including endemic species, are slow to recover. Complicating plant‐community restoration efforts, many tropical grassland species, particularly those that invest in underground storage organs, are difficult to propagate and re‐establish. To guide restoration decisions, we draw on the old‐growth grassland concept, the novel ecosystem concept, and theory regarding tree cover along resource gradients in savannas to propose a conceptual framework that classifies tropical grasslands into three broad ecosystem states. These states are: (1) old‐growth grasslands (i.e. ancient, biodiverse grassy ecosystems), where management should focus on the maintenance of disturbance regimes; (2) hybrid grasslands, where restoration should emphasise a return towards the old‐growth state; and (3) novel ecosystems, where the magnitude of environmental change (i.e. a shift to an alternative ecosystem state) or the socioecological context preclude a return to historical conditions.

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Vegetação campestre do sul do Brasil: dinâmica de espécies à exclusão do gado

Cited by 47 publications

References 14 publications

Grazing Changes the Soil-Plant Relationship in the Tree-Regeneration Stratum in the Pampa of Souhtern Brazil

Grazing Changes the Soil-Plant Relationship in the Tree-Regeneration Stratum in the Pampa of Souhtern Brazil

Vegetação campestre de areais do Sudoeste do Rio Grande do Sul sob pastejo e com exclusão do pastejo

Resilience and restoration of tropical and subtropical grasslands, savannas, and grassy woodlands

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