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Regime shift by an exotic nitrogen-fixing shrub mediates plant facilitation in primary succession.

Stinca A, Chirico GB, Incerti G, Bonanomi G - PLoS ONE (2015)

Bottom Line: Moreover, G. aetnensis mitigates the daily range of soil temperature, reducing the exposure of coexisting plants to extremely high temperatures and water loss by soil evaporation, particularly during the growing season.Such amelioration of soil quality, coupled with the mitigation of below-canopy microclimatic conditions, has enhanced plant colonization of the barren Grand Cone slopes, by both herbaceous and woody species.Further studies are needed to identity specific management practices that can limit the spread and impacts of this species.

View Article: PubMed Central - PubMed

Affiliation: Department of Agriculture, University of Naples Federico II, via Università 100, Portici (Naples), Italy.

ABSTRACT
Ecosystem invasion by non-native, nitrogen-fixing species is a global phenomenon with serious ecological consequences. However, in the Mediterranean basin few studies addressed the impact of invasion by nitrogen-fixing shrubs on soil quality and hydrological properties at local scale, and the possible effects on succession dynamics and ecosystem invasibility by further species. In this multidisciplinary study we investigated the impact of Genista aetnensis (Biv.) DC., an exotic nitrogen-fixing shrub, on the Vesuvius Grand Cone (Southern Italy). Specifically, we tested the hypotheses that the invasion of G. aetnensis has a significant impact on soil quality, soil hydrological regime, local microclimate and plant community structure, and that its impact increases during the plant ontogenetic cycle. We showed that G. aetnensis, in a relatively short time-span (i.e. ~ 40 years), has been able to build-up an island of fertility under its canopy, by accumulating considerable stocks of C, N, and P in the soil, and by also improving the soil hydrological properties. Moreover, G. aetnensis mitigates the daily range of soil temperature, reducing the exposure of coexisting plants to extremely high temperatures and water loss by soil evaporation, particularly during the growing season. Such amelioration of soil quality, coupled with the mitigation of below-canopy microclimatic conditions, has enhanced plant colonization of the barren Grand Cone slopes, by both herbaceous and woody species. These results suggest that the invasion of G. aetnensis could eventually drive to the spread of other, more resource-demanding exotic species, promoting alternative successional trajectories that may dramatically affect the local landscape. Our study is the first record of the invasion of G. aetnensis, an additional example of the regime shifts driven by N-fixing shrubs in Mediterranean region. Further studies are needed to identity specific management practices that can limit the spread and impacts of this species.

No MeSH data available.


Related in: MedlinePlus

Yearly effects of Genista aetnensis on vegetation.Time-dependency of the effects of Genista aetnensis ontogenetic stage on plant living biomass (top) and species richness (bottom) under (left) or outside (right) the canopy of Genista individuals. Data refer to mean and 95% confidence interval of data recorded in two surveys in the years 2010 and 2011 (N = 60 for each bar). Significantly higher time-dependent values within each ontogenetic stage are marked with an asterisk (Post-hoc Duncan test at p<0.05, interactions of year and ontogenetic stage from GLMs in S10 Table).
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pone.0123128.g006: Yearly effects of Genista aetnensis on vegetation.Time-dependency of the effects of Genista aetnensis ontogenetic stage on plant living biomass (top) and species richness (bottom) under (left) or outside (right) the canopy of Genista individuals. Data refer to mean and 95% confidence interval of data recorded in two surveys in the years 2010 and 2011 (N = 60 for each bar). Significantly higher time-dependent values within each ontogenetic stage are marked with an asterisk (Post-hoc Duncan test at p<0.05, interactions of year and ontogenetic stage from GLMs in S10 Table).

Mentions: Overall, 68 taxa were recorded at the study sites (S9 Table). Most plants are either annual or perennial grasses, but seedlings of shrubs and trees were also found, as well as one lichen (Stereocaulon vesuvianum Pers.) and several mosses (S9 Table). Plant diversity was far more high under Genista canopies compared to the outside areas, as coherently showed by distributional patterns (Table 2, Fig 6) of total living biomass (mean and s.e.m. of 216.1±12.3 g m-2 and 50.5±4.6 g m-2 under and outside the canopy, respectively), standing litter (540.2±26.0 g m-2 and 1.6±0.5 g m-2), and species richness (3.18±0.13 and 1.48±0.09 species per plot, respectively).


Regime shift by an exotic nitrogen-fixing shrub mediates plant facilitation in primary succession.

Stinca A, Chirico GB, Incerti G, Bonanomi G - PLoS ONE (2015)

Yearly effects of Genista aetnensis on vegetation.Time-dependency of the effects of Genista aetnensis ontogenetic stage on plant living biomass (top) and species richness (bottom) under (left) or outside (right) the canopy of Genista individuals. Data refer to mean and 95% confidence interval of data recorded in two surveys in the years 2010 and 2011 (N = 60 for each bar). Significantly higher time-dependent values within each ontogenetic stage are marked with an asterisk (Post-hoc Duncan test at p<0.05, interactions of year and ontogenetic stage from GLMs in S10 Table).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4383633&req=5

pone.0123128.g006: Yearly effects of Genista aetnensis on vegetation.Time-dependency of the effects of Genista aetnensis ontogenetic stage on plant living biomass (top) and species richness (bottom) under (left) or outside (right) the canopy of Genista individuals. Data refer to mean and 95% confidence interval of data recorded in two surveys in the years 2010 and 2011 (N = 60 for each bar). Significantly higher time-dependent values within each ontogenetic stage are marked with an asterisk (Post-hoc Duncan test at p<0.05, interactions of year and ontogenetic stage from GLMs in S10 Table).
Mentions: Overall, 68 taxa were recorded at the study sites (S9 Table). Most plants are either annual or perennial grasses, but seedlings of shrubs and trees were also found, as well as one lichen (Stereocaulon vesuvianum Pers.) and several mosses (S9 Table). Plant diversity was far more high under Genista canopies compared to the outside areas, as coherently showed by distributional patterns (Table 2, Fig 6) of total living biomass (mean and s.e.m. of 216.1±12.3 g m-2 and 50.5±4.6 g m-2 under and outside the canopy, respectively), standing litter (540.2±26.0 g m-2 and 1.6±0.5 g m-2), and species richness (3.18±0.13 and 1.48±0.09 species per plot, respectively).

Bottom Line: Moreover, G. aetnensis mitigates the daily range of soil temperature, reducing the exposure of coexisting plants to extremely high temperatures and water loss by soil evaporation, particularly during the growing season.Such amelioration of soil quality, coupled with the mitigation of below-canopy microclimatic conditions, has enhanced plant colonization of the barren Grand Cone slopes, by both herbaceous and woody species.Further studies are needed to identity specific management practices that can limit the spread and impacts of this species.

View Article: PubMed Central - PubMed

Affiliation: Department of Agriculture, University of Naples Federico II, via Università 100, Portici (Naples), Italy.

ABSTRACT
Ecosystem invasion by non-native, nitrogen-fixing species is a global phenomenon with serious ecological consequences. However, in the Mediterranean basin few studies addressed the impact of invasion by nitrogen-fixing shrubs on soil quality and hydrological properties at local scale, and the possible effects on succession dynamics and ecosystem invasibility by further species. In this multidisciplinary study we investigated the impact of Genista aetnensis (Biv.) DC., an exotic nitrogen-fixing shrub, on the Vesuvius Grand Cone (Southern Italy). Specifically, we tested the hypotheses that the invasion of G. aetnensis has a significant impact on soil quality, soil hydrological regime, local microclimate and plant community structure, and that its impact increases during the plant ontogenetic cycle. We showed that G. aetnensis, in a relatively short time-span (i.e. ~ 40 years), has been able to build-up an island of fertility under its canopy, by accumulating considerable stocks of C, N, and P in the soil, and by also improving the soil hydrological properties. Moreover, G. aetnensis mitigates the daily range of soil temperature, reducing the exposure of coexisting plants to extremely high temperatures and water loss by soil evaporation, particularly during the growing season. Such amelioration of soil quality, coupled with the mitigation of below-canopy microclimatic conditions, has enhanced plant colonization of the barren Grand Cone slopes, by both herbaceous and woody species. These results suggest that the invasion of G. aetnensis could eventually drive to the spread of other, more resource-demanding exotic species, promoting alternative successional trajectories that may dramatically affect the local landscape. Our study is the first record of the invasion of G. aetnensis, an additional example of the regime shifts driven by N-fixing shrubs in Mediterranean region. Further studies are needed to identity specific management practices that can limit the spread and impacts of this species.

No MeSH data available.


Related in: MedlinePlus