Limits...
Missing species among Mediterranean non-Siphonophoran Hydrozoa.

Gravili C, Bevilacqua S, Terlizzi A, Boero F - Biodivers. Conserv. (2015)

Bottom Line: Realistic assessments of species pools require addition of new species, but also subtraction of species not found since a certain period.As consequence, the regional biodiversity should be analyzed through its temporal evolution, to detect changes and their possible causes.This approach has profound consequences on biodiversity assessments and also on the compilation of red lists.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Zoology and Marine Biology, Dipartimento di Scienze e Tecnologie Biologiche e Ambientali, Di.S.Te.B.A., Università del Salento, Via Prov.le Lecce-Monteroni, 73100 Lecce, Italy.

ABSTRACT

Hydrozoa of the Mediterranean Sea are well known and a recent monograph covers 457 species. Mediterranean non-Siphonophoran Hydrozoa comprises 398 species, an increasing number due to continuous updates, representing about 10 % of the 3,702 currently valid species reported in a recent world assessment of hydrozoan diversity. Many new records are non indigenous species, previously described species that occurred elsewhere and whose arrival was presumably caused by human activities. However, many species reported in the past are not recorded in recent times. Realistic assessments of species pools require addition of new species, but also subtraction of species not found since a certain period. With the confidence of extinction index, cases of putative extinction can be raised. Out of the 398 known species, only 162 (41 %) have been reported in the last decade, while 53 (13 %) are not recorded in the literature since at least 41 years. According to the confidence of extinction index, 60 % of the 53 missing species are extinct, and 11 % are putatively extinct from the basin. From a biogeographical point of view, the missing species are: 34 % endemic, 19 % boreal, 15 % Mediterranean-Atlantic, 11 % Indo-Pacific, 11 % circumtropical, 4 % cosmopolitan, 2 % tropical-Atlantic, 4 % non-classifiable. Fluctuations in species composition into a certain area cause heavy variability in the expression of both structural and functional biodiversity. As consequence, the regional biodiversity should be analyzed through its temporal evolution, to detect changes and their possible causes. This approach has profound consequences on biodiversity assessments and also on the compilation of red lists.

No MeSH data available.


Related in: MedlinePlus

Canonical analysis of principal coordinates (CAP) for the factor period based on the distance matrix (Jaccard’s distance) among sector × period points. Open triangle >40 years, open diamond 40 years, open square 30 years, open circle 20 years, asterisk 10 years
© Copyright Policy - OpenAccess
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4514666&req=5

Fig4: Canonical analysis of principal coordinates (CAP) for the factor period based on the distance matrix (Jaccard’s distance) among sector × period points. Open triangle >40 years, open diamond 40 years, open square 30 years, open circle 20 years, asterisk 10 years

Mentions: CAP analysis showed a clear separation of points of > 40 years (left down corner of the plot) from those of 10 years (right down corner), with intermediate position of points of 40, 30, and 20 years (Fig. 4), indicating a temporal gradient of species composition of NSH in the Mediterranean. A total of 171 NSH species showed a correlation value > 0.2 with canonical axes, the 35 % of them being NSHMs (20 %) or NIS (15 %).Fig. 4


Missing species among Mediterranean non-Siphonophoran Hydrozoa.

Gravili C, Bevilacqua S, Terlizzi A, Boero F - Biodivers. Conserv. (2015)

Canonical analysis of principal coordinates (CAP) for the factor period based on the distance matrix (Jaccard’s distance) among sector × period points. Open triangle >40 years, open diamond 40 years, open square 30 years, open circle 20 years, asterisk 10 years
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4514666&req=5

Fig4: Canonical analysis of principal coordinates (CAP) for the factor period based on the distance matrix (Jaccard’s distance) among sector × period points. Open triangle >40 years, open diamond 40 years, open square 30 years, open circle 20 years, asterisk 10 years
Mentions: CAP analysis showed a clear separation of points of > 40 years (left down corner of the plot) from those of 10 years (right down corner), with intermediate position of points of 40, 30, and 20 years (Fig. 4), indicating a temporal gradient of species composition of NSH in the Mediterranean. A total of 171 NSH species showed a correlation value > 0.2 with canonical axes, the 35 % of them being NSHMs (20 %) or NIS (15 %).Fig. 4

Bottom Line: Realistic assessments of species pools require addition of new species, but also subtraction of species not found since a certain period.As consequence, the regional biodiversity should be analyzed through its temporal evolution, to detect changes and their possible causes.This approach has profound consequences on biodiversity assessments and also on the compilation of red lists.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Zoology and Marine Biology, Dipartimento di Scienze e Tecnologie Biologiche e Ambientali, Di.S.Te.B.A., Università del Salento, Via Prov.le Lecce-Monteroni, 73100 Lecce, Italy.

ABSTRACT

Hydrozoa of the Mediterranean Sea are well known and a recent monograph covers 457 species. Mediterranean non-Siphonophoran Hydrozoa comprises 398 species, an increasing number due to continuous updates, representing about 10 % of the 3,702 currently valid species reported in a recent world assessment of hydrozoan diversity. Many new records are non indigenous species, previously described species that occurred elsewhere and whose arrival was presumably caused by human activities. However, many species reported in the past are not recorded in recent times. Realistic assessments of species pools require addition of new species, but also subtraction of species not found since a certain period. With the confidence of extinction index, cases of putative extinction can be raised. Out of the 398 known species, only 162 (41 %) have been reported in the last decade, while 53 (13 %) are not recorded in the literature since at least 41 years. According to the confidence of extinction index, 60 % of the 53 missing species are extinct, and 11 % are putatively extinct from the basin. From a biogeographical point of view, the missing species are: 34 % endemic, 19 % boreal, 15 % Mediterranean-Atlantic, 11 % Indo-Pacific, 11 % circumtropical, 4 % cosmopolitan, 2 % tropical-Atlantic, 4 % non-classifiable. Fluctuations in species composition into a certain area cause heavy variability in the expression of both structural and functional biodiversity. As consequence, the regional biodiversity should be analyzed through its temporal evolution, to detect changes and their possible causes. This approach has profound consequences on biodiversity assessments and also on the compilation of red lists.

No MeSH data available.


Related in: MedlinePlus