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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

Results of the litter decomposition experiment.Dynamics of litter mass (% of initial value) in litterbags decomposing for 360 days under (IN) and outside (OUT) the canopy of adult Genista aetnensis individuals, and corresponding changes of cellulose and lignin percent content (top), C-to-N and lignin-to-N ratios (bottom) and N percent content (inset). Data refer to mean and standard deviation of 10 replicates for each harvesting date. Data of chemical variables (cellulose, lignin, N, C-to-N and lignin-to-N ratios) are pooled for IN and OUT areas, since such factor did not affect significantly litter decomposition in the field (S6 Table).
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pone.0123128.g002: Results of the litter decomposition experiment.Dynamics of litter mass (% of initial value) in litterbags decomposing for 360 days under (IN) and outside (OUT) the canopy of adult Genista aetnensis individuals, and corresponding changes of cellulose and lignin percent content (top), C-to-N and lignin-to-N ratios (bottom) and N percent content (inset). Data refer to mean and standard deviation of 10 replicates for each harvesting date. Data of chemical variables (cellulose, lignin, N, C-to-N and lignin-to-N ratios) are pooled for IN and OUT areas, since such factor did not affect significantly litter decomposition in the field (S6 Table).

Mentions: Litter decomposition did not show significant variations between litterbags placed under and outside Genista canopy (Fig 2A, S5 Table). On the contrary, all litter variables significantly changed during decomposition time (S6 Table).


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)

Results of the litter decomposition experiment.Dynamics of litter mass (% of initial value) in litterbags decomposing for 360 days under (IN) and outside (OUT) the canopy of adult Genista aetnensis individuals, and corresponding changes of cellulose and lignin percent content (top), C-to-N and lignin-to-N ratios (bottom) and N percent content (inset). Data refer to mean and standard deviation of 10 replicates for each harvesting date. Data of chemical variables (cellulose, lignin, N, C-to-N and lignin-to-N ratios) are pooled for IN and OUT areas, since such factor did not affect significantly litter decomposition in the field (S6 Table).
© Copyright Policy
Related In: Results  -  Collection

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

pone.0123128.g002: Results of the litter decomposition experiment.Dynamics of litter mass (% of initial value) in litterbags decomposing for 360 days under (IN) and outside (OUT) the canopy of adult Genista aetnensis individuals, and corresponding changes of cellulose and lignin percent content (top), C-to-N and lignin-to-N ratios (bottom) and N percent content (inset). Data refer to mean and standard deviation of 10 replicates for each harvesting date. Data of chemical variables (cellulose, lignin, N, C-to-N and lignin-to-N ratios) are pooled for IN and OUT areas, since such factor did not affect significantly litter decomposition in the field (S6 Table).
Mentions: Litter decomposition did not show significant variations between litterbags placed under and outside Genista canopy (Fig 2A, S5 Table). On the contrary, all litter variables significantly changed during decomposition time (S6 Table).

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