Limits...
Oceanographic Conditions Limit the Spread of a Marine Invader along Southern African Shores.

Assis J, Zupan M, Nicastro KR, Zardi GI, McQuaid CD, Serrão EA - PLoS ONE (2015)

Bottom Line: The mussel Mytilus galloprovincialis is native to the Mediterranean and is the most successful marine invader in southern Africa.On the southeast coast, nearshore currents give larvae the potential to move eastwards, against the prevalent Agulhas current and beyond the present distributional limit, however environmental conditions prevent the establishment of the species.The transition between the cooler and warmer water regimes is therefore the main factor limiting the northern spread on the southeast coast; however, biotic interactions with native fauna may also play an important role.

View Article: PubMed Central - PubMed

Affiliation: Center of Marine Sciences, University of Algarve, Faro, Portugal.

ABSTRACT
Invasive species can affect the function and structure of natural ecological communities, hence understanding and predicting their potential for spreading is a major ecological challenge. Once established in a new region, the spread of invasive species is largely controlled by their dispersal capacity, local environmental conditions and species interactions. The mussel Mytilus galloprovincialis is native to the Mediterranean and is the most successful marine invader in southern Africa. Its distribution there has expanded rapidly and extensively since the 1970s, however, over the last decade its spread has ceased. In this study, we coupled broad scale field surveys, Ecological Niche Modelling (ENM) and Lagrangian Particle Simulations (LPS) to assess the current invaded distribution of M. galloprovincialis in southern Africa and to evaluate what prevents further spread of this species. Results showed that all environmentally suitable habitats in southern Africa have been occupied by the species. This includes rocky shores between Rocky Point in Namibia and East London in South Africa (approx. 2800 km) and these limits coincide with the steep transitions between cool-temperate and subtropical-warmer climates, on both west and southeast African coasts. On the west coast, simulations of drifting larvae almost entirely followed the northward and offshore direction of the Benguela current, creating a clear dispersal barrier by advecting larvae away from the coast. On the southeast coast, nearshore currents give larvae the potential to move eastwards, against the prevalent Agulhas current and beyond the present distributional limit, however environmental conditions prevent the establishment of the species. The transition between the cooler and warmer water regimes is therefore the main factor limiting the northern spread on the southeast coast; however, biotic interactions with native fauna may also play an important role.

No MeSH data available.


Principal Component Analysis (PCA) of the environmental space used by native (grey circles) and non-native (red circles) occurrences of M. galloprovincialis.The grey polygon indicates the overall environmental space of the species. The significance levels of the permutational multivariate ANOVA (PERMANOVA) and permutational analysis of multivariate dispersion (PERMDISP) to test for niche divergence between native and non-native ranges are shown.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4482700&req=5

pone.0128124.g003: Principal Component Analysis (PCA) of the environmental space used by native (grey circles) and non-native (red circles) occurrences of M. galloprovincialis.The grey polygon indicates the overall environmental space of the species. The significance levels of the permutational multivariate ANOVA (PERMANOVA) and permutational analysis of multivariate dispersion (PERMDISP) to test for niche divergence between native and non-native ranges are shown.

Mentions: The first two PCA components performed to infer niche divergence explained 66.54% of the variability found in the environmental data. This analysis showed that the invasive occurrences use part of the native environmental space (Fig 3). PERMANOVA and PERMDISP further confirmed this, indicating that a niche shift by M. galloprovincialis during its spread through southern Africa was unlikely (PERMANOVA Pseudo-F: 2.801; p: 0.084) and that the native ecological niche is wider (i.e., more dispersed) than the invaded one (PERMDISP F: 138.1; p: < 0.001).


Oceanographic Conditions Limit the Spread of a Marine Invader along Southern African Shores.

Assis J, Zupan M, Nicastro KR, Zardi GI, McQuaid CD, Serrão EA - PLoS ONE (2015)

Principal Component Analysis (PCA) of the environmental space used by native (grey circles) and non-native (red circles) occurrences of M. galloprovincialis.The grey polygon indicates the overall environmental space of the species. The significance levels of the permutational multivariate ANOVA (PERMANOVA) and permutational analysis of multivariate dispersion (PERMDISP) to test for niche divergence between native and non-native ranges are shown.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482700&req=5

pone.0128124.g003: Principal Component Analysis (PCA) of the environmental space used by native (grey circles) and non-native (red circles) occurrences of M. galloprovincialis.The grey polygon indicates the overall environmental space of the species. The significance levels of the permutational multivariate ANOVA (PERMANOVA) and permutational analysis of multivariate dispersion (PERMDISP) to test for niche divergence between native and non-native ranges are shown.
Mentions: The first two PCA components performed to infer niche divergence explained 66.54% of the variability found in the environmental data. This analysis showed that the invasive occurrences use part of the native environmental space (Fig 3). PERMANOVA and PERMDISP further confirmed this, indicating that a niche shift by M. galloprovincialis during its spread through southern Africa was unlikely (PERMANOVA Pseudo-F: 2.801; p: 0.084) and that the native ecological niche is wider (i.e., more dispersed) than the invaded one (PERMDISP F: 138.1; p: < 0.001).

Bottom Line: The mussel Mytilus galloprovincialis is native to the Mediterranean and is the most successful marine invader in southern Africa.On the southeast coast, nearshore currents give larvae the potential to move eastwards, against the prevalent Agulhas current and beyond the present distributional limit, however environmental conditions prevent the establishment of the species.The transition between the cooler and warmer water regimes is therefore the main factor limiting the northern spread on the southeast coast; however, biotic interactions with native fauna may also play an important role.

View Article: PubMed Central - PubMed

Affiliation: Center of Marine Sciences, University of Algarve, Faro, Portugal.

ABSTRACT
Invasive species can affect the function and structure of natural ecological communities, hence understanding and predicting their potential for spreading is a major ecological challenge. Once established in a new region, the spread of invasive species is largely controlled by their dispersal capacity, local environmental conditions and species interactions. The mussel Mytilus galloprovincialis is native to the Mediterranean and is the most successful marine invader in southern Africa. Its distribution there has expanded rapidly and extensively since the 1970s, however, over the last decade its spread has ceased. In this study, we coupled broad scale field surveys, Ecological Niche Modelling (ENM) and Lagrangian Particle Simulations (LPS) to assess the current invaded distribution of M. galloprovincialis in southern Africa and to evaluate what prevents further spread of this species. Results showed that all environmentally suitable habitats in southern Africa have been occupied by the species. This includes rocky shores between Rocky Point in Namibia and East London in South Africa (approx. 2800 km) and these limits coincide with the steep transitions between cool-temperate and subtropical-warmer climates, on both west and southeast African coasts. On the west coast, simulations of drifting larvae almost entirely followed the northward and offshore direction of the Benguela current, creating a clear dispersal barrier by advecting larvae away from the coast. On the southeast coast, nearshore currents give larvae the potential to move eastwards, against the prevalent Agulhas current and beyond the present distributional limit, however environmental conditions prevent the establishment of the species. The transition between the cooler and warmer water regimes is therefore the main factor limiting the northern spread on the southeast coast; however, biotic interactions with native fauna may also play an important role.

No MeSH data available.