From individuals to communities: How singleton invasive pine saplings lead to biodiversity change in the Brazilian Cerrado hotspot (original) (raw)
Related papers
Anais da Academia Brasileira de Ciências
Biological invasion is a major threat to global biodiversity and ecosystem services. We examined the functional traits similarity between a set of native and nonnative invasive tree species from the Southern Brazilian subtropical mixed forest, part of an important global hotspot for biodiversity conservation. We hypothesized that invasive species occupy marginal niche spaces. We ordered the species using the Principal Component Analysis based on their wood density, leaf area, and specifi c leaf area. These are all important traits that summarize essential ecological strategies associated with resource acquisition and conservation. Functional overlaps between non-native and native species were analyzed through kernel density estimation of continuous traits data. While native and non-native invasive species were distributed along the same functional gradients, the position of non-native species in the functional space is species and traits specifi c. We concluded that within Brazilian subtropical mixed forests, the functional dissimilarity as a key factor in invasion success could not be generalized for all species and traits.
Invasive Exotic Trees in the Conservation Units in Curitiba, Brazil
Acta Horticulturae, 2010
One of the greatest challenges worldwide is the loss of biodiversity in Conservation Units (CUs) due to their infestation by invasive exotic trees (IETs). Aiming to provide additional basis to a better understanding of the IETs global dispersion as well as to their local control, the results from a qualitative and quantitative IETs survey (DBH ≥ 15 cm) at 22 CUs of Curitiba (Parana State, Southern Brazil) are presented and discussed.
Community structure, succession and invasibility in a seasonal deciduous forest in southern Brazil
Biological Invasions, 2014
Majority of invasive trees colonize grasslands, shrublands, and temperate forests. Hovenia dulcis is an exception, because it is one of the most pervasive invaders in Brazilian subtropical forests where it has changed their structure and composition. This study has aimed to identify the clues for its success by defining the structural and functional characteristics of plant communities in different stages of succession with and without H. dulcis. Following the general assumptions of invasion ecology, we expected that H. dulcis establishment and invasion success would be significantly higher in early successional communities, with high resource availability and low species richness and diversity, as well as low functional diversity. Contrary to this hypothesis, no differences were found between plant communities invaded and non-invaded by H. dulcis at three different succession stages. No relationship was found between species richness and diversity and functional diversity, with respect to invasibility along the successional gradient. Hovenia dulcis is strongly associated with semi-open vegetation, where the species was found in higher density. The invasion of open vegetation is more recent, providing evidence of the species's ability to invade plant communities in early successional stages. We concluded that the colonization by H. dulcis was associated with forest openness, but the species is also able to colonize semi-Electronic supplementary material The online version of this article (
Phylogeny, traits, environment, and space in cerrado plant communities at Emas National Park (Brazil
Fuel and Energy Abstracts, 2011
Soil, drought, and fire are abiotic factors that may act as environmental filters in the cerrado, the Brazilian savanna. We used a framework to analyze environmental filtering in geographic and phylogenetic context, sampling woody species in one of the largest cerrado reserves. In 100 quadrats, we measured 10 functional traits on each woody individual. We also measured several soil variables, altitude and slope as a rough surrogate of water availability, interval between fires, and time since last fire. Almost all environmental variables were spatially auto-correlated. We found an overall trait clustering, but not an overall phylogenetic clustering. Nevertheless, we found a phylogenetic signal for some traits. Linking phylogeny, traits, environment, and space, we were able to detect a major dichotomy between two geomorphological units. The flat tableland was positively related with altitude, fire frequency, and nutrient-richer soil. Environmental filtering caused by water availability and fire lead to trait clustering, with smaller shrubs and trees that presented thicker barks, denser woods, sclerophyllous leaves, highlighted by the prevalance of Myrtaceae. The other geomorphological unit, hilly terrain, was positively related with slope, low fire frequency, and nutrient-poorer soil. Environmental filtering was caused especially by nutrient-poor soil that lead to trait clustering, assembling taller trees, with thinner barks, lighter woods, and compound, large, tender, nutrient-richer leaves, distributed across many lineages, including Fabaceae. Hence, the high environmental variability in space with different environmental filters assembled different combination of plant traits and lineages, increasing the overall diversity in cerrado.
Can native vegetation recover after slash pine cultivation in the Brazilian Savanna
Fuel and Energy Abstracts, 2011
There is a widespread view that forest plantations with exotic species are green deserts, unable to sustain biodiversity. Few studies have demonstrated, however, that planted stands of exotic trees have a greater negative effect on the plant diversity of savanna vegetation. We compared the native woody flora under four stands of slash pine of about 45 years old with four stands where the previously existing native Cerrado vegetation was preserved and protected from disturbances for the same period, has changed into dense vegetation -the ''cerradão'', at Assis municipality, São Paulo State, Brazil. Aiming at understanding the potential ecological filters driving these communities, we assessed air and soil humidity, light availability and classified the native species on the basis of shade tolerance, dispersal syndrome and biomes in which they occur (Atlantic Forest or Cerrado). We recorded an average of 70 (±13) species under pine stands and 54 (±16) species in cerradão. Of the total of 136 species recorded, 78 occurred in both habitats, eight were exclusive to the ''cerradão'' (shade tolerant and also occurring in forest ecosystems) and 18 were recorded only under pine stands (82% heliophytic, exclusive to the Cerrado biome). Among the functional attributes and abiotic variables analyzed, only light availability explained the floristic differences found. Since richness was higher under pine, we refuted the hypothesis that exotic species constrain the establishment of the native species richness in the understory. On the other hand, the dark environment under the closed-canopy of the ''cerradão'' acts as a filter inhibiting the establishment of typical Cerrado species. Since pine stands, if managed in long cycle, maintain a reasonable pool of Cerrado endemic species in the understory pine plantations may be a good starting point for savanna restoration.
Restoration Ecology, 2009
Plantations of native-tree species are often recommended for ecological restoration, but the understanding of how these techniques catalyze natural ecological processes is limited. We investigated natural regeneration in five plantations of native trees in the Poço das Antas Biological Reserve (PABR) in the state of Rio de Janeiro, Brazil. The plantations were 9–11 years old, and contained 8–14 native-tree species with different compositions and relative density of species. We analyzed floristic composition, structure (density and basal area) of overstory and understory strata, as well as other ecological attributes (dispersal syndromes, fruit or seed size, and the availability of fruit for frugivores). Zoochorous species comprised 77% of the community, with a prevalence of the two smallest size classes of propagules (< 0.6 and 0.6–1.6 cm) in natural regeneration. The density of zoochorous plants in the understory was positively correlated with their density in the overstory, indicating their influence on natural regeneration (r2 = 0.36; p < 0.0002). Fruit availability for frugivores (density and richness of plants fruiting during the year) was also positively correlated with the density of stems in the understory. Therefore, attributes such as dispersal syndrome and fruiting season should be considered in selecting species to be planted. The differences in natural regeneration observed in each of the native-tree plantations indicated that the performance of plantations as a restoration strategy may differ, depending on initial species composition, planting density, and site conditions.
Perspectives in Ecology and Conservation, 2019
Some Cerrado areas are suppressed by pine tree cultivation. These monoculture processes can exclude the fire presence and inhibit native species development. In Southeastern Brazil, thousands of hectares were planted with these exotic trees 44 years ago, and nowadays, efforts to remove these plantations and restore the native vegetation are being implemented. However, little is known about the regeneration of Cerrado after pine removal. Thus, the aim of this study was to analyze the native plant community of Cerrado, using some techniques to enhance species natural regeneration three years after pine trees removal in areas where plantations existed since 1966. Before treatments application, surveys of the herbaceous and woody community were conducted, followed by the treatment application (fire and the removal of needles) as a management intervention. Moreover, we established control plots, with no intervention. Four and 30 months after treatment application, the herbaceous and woody vegetation, as well as the dead biomass and bare soil components were monitored to observe their regeneration. The pine removal contributed to species development and both techniques contributed to soil exposition, opening space for colonization and species to resprout. The woody and herbaceous group increased in cover, mostly in fire plots, due to the soil exposition increasing light and contributing to species development.
Species richness both impedes and promotes alien plant invasions in the Brazilian Cerrado
Scientific Reports
Worldwide, alien plant invasions have been intensively studied in the past decades, but mechanisms controlling the invasibility of native communities are not fully understood yet. The stochastic niche hypothesis predicts that species-rich plant communities are less prone to alien plant invasions than species-poor communities, which is supported by some but not all field studies, with some very species-rich communities such as the Brazilian Cerrado becoming heavily invaded. However, species-rich communities potentially contain a greater variety of facilitative interactions in resource exploitation than species-poor communities, from which invasive plants might benefit. This alternative hypothetical mechanism might explain why nutrient-poor, species-rich ecosystems are prone to invasion. Here we show that a high species richness both impedes and promotes invasive plants in the Brazilian Cerrado, using structural equation modelling and data from 38 field sites. We found support for the stochastic niche hypothesis through an observed direct negative influence of species richness on abundance of alien invasive species, but an indirect positive effect of species richness on invasive alien plants through soil phosphatase activity that enhances P availability was also found. These field observations were supported with results from a mesocosm experiment. Root phosphatase activity of plants increased with species richness in the mesocosms, which was associated with greater community P and N uptake. The most prominent alien grass species of the region, Melinis minutiflora, benefited most from the higher N and P availability in the species mixtures. Hence, this study provides a novel explanation of why species-richness may sometimes promote rather than impede invasion, and highlights the need to perform facilitation experiments in multi-species communities. The invasion of natural ecosystems by alien plants is recognized as an important component of global environmental change 1-3 , and potentially poses a major threat to biodiversity 4,5. Getting insight in the mechanisms of alien plant invasions, therefore, has become a major research priority in ecology. Central research questions related to alien plant invasions are: (1) what makes a species invasive?, (2) what are the effects of alien plant invasions on plant communities and ecosystems?, and (3) what makes a native community or habitat 'invasible' or vulnerable for invasion? 6-10. Comparative studies about native and invasive species have shown that many, but not all, invasive species are for instance relatively fast-growing and have a high investment in reproduction 10,11. The effects of alien invasions on native communities and ecosystem properties are variable and depend on environmental conditions; particularly under nutrient-rich conditions they can become very abundant, forming a threat to native plants, and altering soil conditions 8,12,13. Two tenets of the invasibility of native communities and habitats are that species-rich plant communities are less invasible than species-poor communities 14-16 , and that nutrient-poor sites are less prone to invasion than nutrient-rich sites 17,18. However, sometimes also very species-rich communities on nutrient-poor soils are highly invaded 6,19-22 , but this 'paradox of invasion' is only poorly understood, so far.
Australian Journal of Botany, 2020
The aim of this study was to evaluate the vegetation identity of local-scale ecotones and its importance to landscape biodiversity in a transition between savanna and forest vegetation types in Brazil. We surveyed the tree community (diameter at breast height ≥5 cm) within 25 plots of 400 m2 across three core vegetation types and two ecotones among them (totalling five vegetation types). We then evaluated similarities in species composition, community structure and phylogenetic diversity across the transitions in order to assess the relationship between the ecotones and the core areas. Ecotones were distinct floristic units with a high number of unique species and floristic and phylogenetic clustering, and hence these environments are additional vegetation types in relation to the core areas. Some species showed maximum abundance in ecotones, which harboured distinct ecological patterns, demonstrating the importance of the ecotones in the overall ecosystem. Results are related to th...