Seed longevity and seedling emergence rate of <i>Urochloa decumbens</i> as influenced by sowing depth in a Cerrado soil

Dantas-Junior, Ademar Barbosa; Musso, Carolina; Miranda, Heloísa S.

doi:10.1111/gfs.12347

Cited by 14 publications

(8 citation statements)

References 22 publications

(27 reference statements)

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“…This is consistent with other studies, where in most cases, weedinfested plots often have lower assemblage of pasture and broad leaf species (Gioria and Osborne, 2009;Nigatu et al, 2010;Nguyen et al, 2017). The short life span of pasture seeds may also contribute to their low numbers in the soil seed bank (Dantas-Junior et al, 2018). In addition, most pasture grasses are usually perennial which could prioritise vegetative growth over seed production.…”

Section: Discussionsupporting

confidence: 88%

Soil Seed Bank Dynamics of Pastures Invaded by Navua Sedge (Cyperus aromaticus) in Tropical North Queensland

Chadha

Osunkoya²,

Shi³

et al. 2022

Front. Agron.

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Navua sedge (Cyperus aromaticus) is threatening crops, pasture species and natural ecosystems in Pacific Island countries and northern Queensland, Australia. To aid future management efforts of this exotic invasive weed, research was conducted to understand the soil seed bank dynamics of pastures invaded by Navua sedge. Six grazing properties were chosen across two landscapes, coastal and inland/upland, with areas that had Navua sedge infestations in Queensland, Australia. At each site, soil was collected from two soil depths, 0-5 and 5-10 cm, and from plots with high and low infestation levels of Navua sedge. It was observed that the soil seed bank dynamics varied significantly between these study sites. Navua sedge was the dominant species in the soil seed bank at all the sites contributing between 62% to 95% of the total seed bank, while pasture seeds occupied only 3% to 24%. Broadleaf seeds were even lower in abundance, showing between 2% to 13% of the total seed count. The abundance of Navua sedge seed present in the soil was significantly correlated with the aboveground biomass of Navua sedge (r=0.53, p=0.006), but no correlation was found with the infestation age of Navua sedge. Based on this work, it is clear that the seed bank of Navua sedge is very large and concentrated within the top 0-5 cm of the soil, with, 83% of total Navua sedge seeds being in this layer. It was also noted that, although, high infestation plots had significantly higher number of seeds than low infestation plots, more than 18,000 Navua sedge seeds/m2 were still found in the 0-5 cm soil layer of plots regarded as low infestation. We suggest that insights achieved from our soil seed bank study may be used to devise management strategies to minimise the impact of Navua sedge weed in critical grazing and agricultural areas.

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Section: Discussionsupporting

confidence: 88%

Soil Seed Bank Dynamics of Pastures Invaded by Navua Sedge (Cyperus aromaticus) in Tropical North Queensland

Chadha

Osunkoya²,

Shi³

et al. 2022

Front. Agron.

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“…In summary, as the potential of seedling recruitment of invasive species is minimally reduced by light (Fig. 1) and burial depth (Dantas-Junior et al, 2018; Musso et al, 2019), their presence in the soil seed bank could outcompete native species whose seeds show high production of abnormal seedlings and low seedling emergence if buried (Fontenele et al, 2020). Native species, however, may depend on seeds on the soil surface of open vegetation gaps to successfully recruit new individuals since their seeds are light-dependent.…”

Section: Discussionmentioning

confidence: 99%

“…Despite that, these species have been neglected in Cerrado studies and are particularly threatened by competition with invasive African grasses (Zenni and Ziller, 2011; Aires et al, 2014; Musso et al, 2019). Invasive species are widely used as pastures in the Cerrado (Zenni and Ziller, 2011) and tend to show higher seed production and seed quality than the native species (Aires et al, 2014; Dantas-Junior et al, 2018; Musso et al, 2019). Therefore, invasive grasses have the potential to outcompete and displace native species.…”

Section: Introductionmentioning

confidence: 99%

Light affects the germination and normal seedling development of Neotropical savanna grasses

et al. 2020

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The Cerrado is a Neotropical savanna where grasses are a major biomass component in the open vegetation physiognomies. Invasive grasses are widely used as pastures in the Cerrado, and their presence may displace native species. The persistence of native grasses relies also on reproduction via seeds, which is often dependent on seeds found buried in the soil seed bank. The literature about the effects of light availability on the germination of Neotropical savanna grasses is scarce, and germination may lead to abnormal seedlings that develop only the root or the shoot. Germination trials that overlook this fact may overestimate the potential for seedling recruitment. Therefore, we tested the effects of light availability on the germination of nine native and two invasive grasses, addressing the production of normal seedlings. Seeds were germinated in the complete absence or the presence of light (12 h photoperiod under white light) for 30 days. Germination was defined as the sum of normal and abnormal seedlings. Eight species were light-dependent, decreasing the production of normal seedlings in the dark. Two native and one invasive species were non-responsive to the dark treatment, showing no change in germination or production of normal seedlings. Our results suggest that seeds buried in the soil seed bank are likely to show reduced germination and develop abnormal seedlings, reinforcing a bottleneck for the recruitment of native grasses. For invasive species, however, the potential of seedling recruitment was minimally reduced by light, suggesting a competitive advantage for the recruitment of these species.

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“…In a few decades, the species invaded millions of hectares of natural ecosystems, becoming a severe threat to Cerrado conservation (Pivello et al 1999b; Durigan et al 2007; Sampaio & Schmidt 2013) and restoration (Silva & Vieira 2017). U. decumbens is a C4 perennial grass, 30–90 cm in height, that has a prostrate or decumbent habit (Morrone & Zuloaga 1992), propagating by seeds that last in the soil seed bank for no more than 6 months (Dantas‐Junior et al 2018).…”

Section: Methodsmentioning

confidence: 99%

Effectiveness and costs of invasive species control using different techniques to restore cerrado grasslands

Assis

Pilon

Siqueira

et al. 2020

Restoration Ecology

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Invasion by exotic grasses is a severe threat to neotropical grasslands conservation and a major challenge for their restoration. To restore fire‐prone cerrado grasslands in southeastern Brazil, which have been massively invaded by the African grass Urochloa decumbens, we tested prescribed fire, herbicides, and hoeing, by themselves or in different combinations. Techniques were compared using ecological indicators (decreasing invasive and increasing native vegetation cover and richness) and cost‐effectiveness. All treatments, except fire alone, were similarly effective in controlling the invasive grass, which was reduced to less than 5% cover after 2 years. However, only hoeing was effective in recovering both ground cover and richness of the native vegetation, which was the restoration goal. Despite not changing ground cover by native vegetation or alien grasses, fire was successful as a complementary technique, by depleting the seed bank of the invasive grass by 40%. Hoeing preceded by fire and followed by a grass‐selective herbicide was the most cost‐effective, requiring US$40 per hectare to increase native ground cover by one percentage point compared to US$93 per hectare if only hoeing. Despite the low cost and efficacy of glyphosate application for controlling the invasive grass, it must be followed by reintroducing the native ground cover through active restoration. If the restoration target is to recover both structure and richness of the native vegetation without planting, hoeing is the best solution to control alien grasses.

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Seed longevity and seedling emergence rate of Urochloa decumbens as influenced by sowing depth in a Cerrado soil

Cited by 14 publications

References 22 publications

Soil Seed Bank Dynamics of Pastures Invaded by Navua Sedge (Cyperus aromaticus) in Tropical North Queensland

Soil Seed Bank Dynamics of Pastures Invaded by Navua Sedge (Cyperus aromaticus) in Tropical North Queensland

Light affects the germination and normal seedling development of Neotropical savanna grasses

Effectiveness and costs of invasive species control using different techniques to restore cerrado grasslands

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