Small seed bank in grasslands and tree plantations in former grassland sites in the South Brazilian highlands

Vieira, Mariana de Souza; Overbeck, Gerhard Ernst

doi:10.1111/btp.12785

Cited by 11 publications

(7 citation statements)

References 36 publications

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“…For starters, it may be explained by the high abundance of certain species in both seed banks which were either absent or rarely present in the above-ground vegetation, such as Juncus pallescens, Juncus marginatus, Bromus subtilis and Cyperus obtusatus. Although this may seem strange at first, it has been registered that species of these families (Cyperaceae and Juncaceae) produce a large quantity of small seeds which are overrepresented in the seed bank (e. g.,Eriksson & Eriksson, 1997;de Vieira & Overbeck, 2020;…”

mentioning

confidence: 99%

Fertilization and overseeding legumes on native grasslands leads to a hardly reversible degraded state

Pañella

Guido

Jaurena

et al. 2022

Applied Vegetation Science

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Aims Diverse practices related to livestock intensification often have a deep impact on grassland diversity. Moreover, alternative degraded states that are hardly reversible can be observed, resulting in low‐diversity communities, dominated by invasive alien species. Therefore, the need arises to understand above‐ground vegetation dynamics in these communities, and the potential of the seed bank to revert this degradation. In this study, we evaluated the impact of overseeding alien legumes coupled with phosphorus fertilization on native grasslands, in terms of above‐ground vegetation composition and soil seed bank. Methods A long‐term experiment (23 years) was performed in eastern Uruguay with three treatments: (1) native grasslands and native grasslands overseeded with alien legumes and fertilized at a (2) moderate or (3) high phosphorus dosage. Vegetation surveys were done in 2009 and 2019 to evaluate changes, and the seed bank was sampled in 2019. Results Native grasslands had higher total richness, native species richness and abundance in both years, as well as a higher species turnover in both temporal and spatial dimensions. The dominant species in overseeded treatments was the invasive alien grass Cynodon dactylon. The seed bank was similar between treatments in terms of seed density and richness, but differed in composition, with a higher abundance of alien species in the overseeded grassland. Seed banks showed low similarity with the above‐ground vegetation. Conclusions The overseeded grassland appears to be in a degraded state of low species diversity, with low turnover and invaded by alien species. The seeds in the soil appear to be insufficient to revert this condition and might be a hindrance for restoration due to the high abundance of alien species. Grasslands that have been degraded by long periods of fertilization and overseeding legumes present a great challenge for ecological restoration, since invasive alien species should be controlled before native species are reintroduced.

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confidence: 99%

Fertilization and overseeding legumes on native grasslands leads to a hardly reversible degraded state

Pañella

Guido

Jaurena

et al. 2022

Applied Vegetation Science

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“…Seed banks also differed between sites. Seed density was higher in CC, although both densities were within the range recorded in different grasslands of the region (Haretche & Rodríguez 2006;Cuello et al 2020;de Souza & Overbeck 2020). In both sites, the group of forbs was the most abundant PFT, which is a rather common feature of grazed grasslands, as the dominant grasses rely to a greater extent on vegetative propagation for their growth and spread (Altesor et al 2005;Haretche & Rodríguez 2006).…”

Section: Belowground Legaciesmentioning

confidence: 66%

“…In southern South America, grassy ecosystems have received little conservation attention (Overbeck et al 2015), and in this region there is virtually no information on the restoration potential of grasslands after afforestation (Torchelsen et al 2019; de Souza & Overbeck 2020). Our results show that the establishment of a forest plantation, even for a short period of time, caused important changes to the ecosystem.…”

Section: Discussionmentioning

confidence: 99%

“…Currently, due to economic or legal issues, some of these plantations are being abandoned after clear-cutting. However, information about the potential for spontaneous recovery of these grasslands is almost nonexistent (but see Torchelsen et al 2019 andde Souza &Overbeck 2020 for neighboring Brazilian grasslands). This knowledge is essential if restoration efforts for this ecosystem are to be implemented.…”

Section: Introductionmentioning

confidence: 99%

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Legacy effects after seven years of afforestation withPinus taedain a natural grassland

Gallego

López‐Mársico

Tommasino

et al. 2023

Restoration Ecology

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The replacement of grassy vegetation by tree monocultures has become an emerging global activity. In South America, about half a million hectares of new plantations are incorporated each year, typically conducted with fast‐growing exotic species, like Pinus and Eucalyptus species. However, information about the potential for spontaneous recovery of these grasslands is almost nonexistent. We assessed the biotic and abiotic legacies left by a 7‐year plantation of Pinus taeda on a natural temperate sub‐humid grassland of Uruguay. In a paired sampling design, comparing a clear‐cut P. taeda plantation and a natural grassland, we analyzed the vegetation richness, cover and composition, the seed bank size and composition, and chemical soil parameters. Afforestation reduced species richness and vegetation cover by 30 and 58%, respectively. Also, species composition differed considerably between sites. Afforestation had a strong negative effect on grass species, excluding the shade‐intolerant C4 grasses that dominate in the grassland. Seed‐bank richness did not differ between sites, but the total seedling density was significantly higher in the plantation compared to the grassland (6,620 and 4,420 seeds/m2, respectively), mainly due to the contribution of forbs. Only 30% of the seed bank species were shared between the two sites. In terms of soil chemical parameters, afforestation induced soil acidification (deviation by 0.15–0.20 pH units) and reduction in soil carbon and cation (Ca and K) concentrations (deviation by 30, 20, and 40%, respectively). Our study showed limited possibilities for passive restoration of a natural grassland of Uruguay after a Pinus afforestation event.

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“…Around the globe, plantations of exotic pines are a threat to biodiversity due to the high risk of invasion into natural areas (Cuevas & Zalba 2010; Simberloff et al 2010). Furthermore, pine plantations reduce native soil seed and bud banks, hindering the potential for natural recovery (Basto et al 2020; Vieira & Overbeck 2020; Ferraro et al 2021). Pine plantations can also negatively affect ecosystem processes and services, including nutrient cycling, groundwater storage, and river discharge (Gyenge et al 2002; Farley & Kelly 2004; Huber et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Restoration of subtropical grasslands degraded by non‐native pine plantations: effects of litter removal and hay transfer

Porto

Prado

Rodrigues

et al. 2022

Restoration Ecology

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Pinus plantations create strong ecological legacies that persist after their removal. We evaluated the effectiveness of pine litter removal (manually or through controlled burns) and hay application for the restoration of South Brazilian coastal grasslands degraded by pine plantations. We installed the experiment 1 year after cutting trees and sampled the vegetation 3 months, 1 year, and 2 years after initiating the experiment. We used generalized linear mixed model to assess treatment effects on plant cover, richness, and pine reestablishment. We used nonmetric multidimensional scaling and indicator species analysis to evaluate changes in species composition over time and in the association of individual species with treatments and reference area. Species richness and vegetation cover did not differ between manual and burn treatments but were higher than in the control. Hay application enhanced vegetation cover by the end of the experiment in all treatments. Hay application enhanced richness initially, but after 2 years the effect persisted only in the burn treatment. Burned plots showed less pine establishment than plots with manual litter removal. Hay‐addition plots contained indicator species present in the reference area. Our results suggest that passive restoration (i.e. only cutting of pine) is not sufficient to restore grasslands altered by afforestation, as residual pine litter constrains the reestablishment of native vegetation. In addition to the benefits of litter removal, our results indicate that hay transfer can overcome seed limitation of grassland species and burning can reduce recolonization by pine.

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Small seed bank in grasslands and tree plantations in former grassland sites in the South Brazilian highlands

Cited by 11 publications

References 36 publications

Fertilization and overseeding legumes on native grasslands leads to a hardly reversible degraded state

Fertilization and overseeding legumes on native grasslands leads to a hardly reversible degraded state

Legacy effects after seven years of afforestation withPinus taedain a natural grassland

Restoration of subtropical grasslands degraded by non‐native pine plantations: effects of litter removal and hay transfer

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