The parasitic water mite Arrenurus papillator on the wings of Sympetrum fonscolombii (Acari; Odon... more The parasitic water mite Arrenurus papillator on the wings of Sympetrum fonscolombii (Acari; Odonata): a review with recent data-The red larvae of the water mite A. papillator are characteristic and easily visible feature on the wings of S. meridionale in central Europe. The attachment of water mites to odonate wings also occurs in other Sympetrum species, especially S. fonscolombii. The aim of this study is to analyse the relatively rare cases in S. fonscolombii recorded from the well-documented influx into Germany in 2015.
In order to quantify the outcome of sperm competition in the mating system of the rove beetle Ale... more In order to quantify the outcome of sperm competition in the mating system of the rove beetle Aleochara curtula we performed three different mating experiment series. Paternity was establishedby DNA ngerprintingwith oligonucleotideprobes. We found a precedence of the last male with a proportion of eggs fathered by the last male of 87% (median). Nevertheless, we observed a large variation of P 2-values in A. curtula and cases of mixed paternity were documented as well as cases of 100% or 0% paternity of the last male. The variation of P 2-values correlates with the ef ciency of spermatophore and sperm transfer.
Somatochlora arctica ist eine hochspezialisierte Spezies, die sich ausschließlich in Kleinstgewäs... more Somatochlora arctica ist eine hochspezialisierte Spezies, die sich ausschließlich in Kleinstgewässern in Mooren unterschiedlicher Art reproduziert. Ihre Larven ertragen sowohl das vorübergehende Austrocknen als auch das Durchfrieren ihrer Gewässer und sind in diesen häufig die einzigen Vertreter der Libellen. Da sowohl die Reproduktionsgewässer als auch die Lebensweise der Art unauffällig sind, ist der Nachweis schwieriger als bei den meisten anderen Arten und gelingt oft nur zufällig. Es ist deshalb davon auszugehen, dass S. arctica im Gebiet weiter verbreitet ist als bislang bekannt. Das Ausmaß der Auswirkungen der extrem trockenen Sommer 2018-2020 kann derzeit noch nicht landesweit eingeschätzt werden, aber zumindest für den Harz ist ein deutlicher Einbruch der Emergenzen belegt. Verbreitung Die eurosibirisch verbreitete Art zeigt innerhalb Europas einen deutlichen Schwerpunkt in der Mitte und im Norden und ist im Süden auf wenige Gebirge beschränkt (Boudot & Karjalainen in Boudot & KalKman 2015: 237-238). In Deutschland ist sie insgesamt sehr lückig verbreitet und hat ihre Siedlungsschwerpunkte in moorreichen Landschaften; innerhalb des Tieflands ist ihr bundesweiter Schwerpunkt im östlichen Niedersachsen (Baumann, BrocKhaus, clausnitzer & ott in BrocKhaus et al. 2015: 238-239).
Details are given on 51 species of dragonflies concerning their distribution, habitats, abundance... more Details are given on 51 species of dragonflies concerning their distribution, habitats, abundance and time of flight in western Lower Saxony (GFR). Of particular interest are the records of indigenous populations of Sympecma paedisca Brauer, Aeshna viridis Eversm., Aeshna isosceles (Müller), Libellula fulva Müller and Sympetrum depressiusculum (Selys) as well as the occurrence of single individuals of Calopteryx virgo (L), Anax parthenope Selys, Cordulegaster boltoni (Don.) and Sympetrum pedemontanum (Allioni).
Durch Torfabbau und Entwässerung war der Libellenbestand des Roten Moores in der hessischen Hochr... more Durch Torfabbau und Entwässerung war der Libellenbestand des Roten Moores in der hessischen Hochrhön akut bedroht. Im Rahmen von Pflegemaßnahmen wurden 1984 die Gräben im Hochmoorbereich angestaut sowie weitere Gewässer auf abgetorften Flächen geschaffen. Diese neu geschaffenen Lebensräume sowie ältere bereits bestehende Weiher am Moorrand wurden 1987/88 auf ihre Libellenfauna hin untersucht. Für das Rote Moor konnten 18 aktuell bodenstendiqe Libellenarten nachgewiesen werden. Die meisten dieser Arten besiedeln die Randbereiche. Doch konnten mit Leucorrhinia dubia, Aeshna juncea, Somatochlora arctica sowie Leucorrhinia pectoralis und Coenagrion hastulatum seltene und gefährdete Arten im Hochmoorbereich nachgewiesen werden. Ausgehend von kleinen Restpopulationen konnten sich besonders Leucorrhinia dubia und Aeshna juncea wieder im Hochmoorbereich in den neugeschaffenen Lebensräumen ausbreiten. Die aktuelle Libellenfauna wird mit dem benachbarten, relativ ungestörten Schwarzen Moor ve...
In order to quantify the outcome of sperm competition in the mating system of the rove beetle Ale... more In order to quantify the outcome of sperm competition in the mating system of the rove beetle Aleochara curtula we performed three different mating experiment series. Paternity was established by DNA fingerprinting with oligonucleotide probes. We found a precedence of the last male with a proportion of eggs fathered by the last male of 87% (median). Nevertheless, we observed a large variation of P2-values in A. curtula and cases of mixed paternity were documented as well as cases of 100% or 0% paternity of the last male. The variation of P2-values correlates with the efficiency of spermatophore and sperm transfer.
Aim: Recent studies suggest insect declines in parts of Europe; however, the generality of these ... more Aim: Recent studies suggest insect declines in parts of Europe; however, the generality of these trends across different taxa and regions remains unclear. Standardized data are not available to assess large-scale, long-term changes for most insect groups but opportunistic citizen science data is widespread for some. Here, we took advantage of citizen science data to investigate distributional changes of Odonata. Location: Germany Methods: We compiled over 1 million occurrence records from different regional databases. We used occupancy-detection models to account for imperfect detection and estimate annual distributions for each species during 1980–2016 within 5 x 5 km quadrants. We also compiled data on species attributes that were hypothesized to affect species' sensitivity to different drivers and related them to the changes in species' distributions. We further developed a novel approach to cluster groups of species with similar patterns of distributional change to repre...
The invasion of Sympetrum fonscolombii into Baden-Württemberg in 2015 (Odonata: Libellulidae)-In ... more The invasion of Sympetrum fonscolombii into Baden-Württemberg in 2015 (Odonata: Libellulidae)-In the federal state of Baden-Württemberg (southwestern Germany) 105 records of Sympetrum fonscolombii from 72 localities were recorded in 2015. The focus of the immigration was placed in the Upper Rhine valley. Successful reproduction of the summer generation in view of permanent colonization of Baden-Württemberg is discussed.
studies on the impact of habitat fragmentation on Coenagrion mercuriale
using genetic methods by... more studies on the impact of habitat fragmentation on Coenagrion mercuriale using genetic methods by microsatellite analysis and GIS models in BadenWürttemberg – Microsatellites are highly variable non-coding genomic regions that are inherited like alleles and therefore can be used for population studies. Genomic DNA, taken from 32 occurrences of the species, was isolated from leg samples of C. mercuriale and amplified by the polymerase chain reaction (PCR). Thirteen microsatellite loci were synthesized by use of specific primers flanking these microsatellite regions according to a standard protocol. These amplification products were separated by length by capillary electrophoresis and assigned to discrete „alleles“. The variability of these DNA sections at the investigated occurrences forms the basis for the statistical evaluations. A range from 0.425 to 0.591 was determined for the expected heterozygosity (He) as a degree for genetic diversity in the study area. The allele number per locus (Na) fluctuated between 2.71 and 4.86. The values within the core zone (patch 2) were relatively constant (He = 0.482-0.541; Na = 4.0-4.8), whereas larger fluctuations were measured in the isolated patches. There was no clear evidence of a bottleneck. The genetic differentiation (calculated as FST/1–FST) is small overall in the study area but increases with distance (isolation by distance; IBD). Values from 0.002 to 0.071 were determined for populations less than five km, and values between 0.006 and 0.205 over 20 km apart. The proportion of migrants was estimated using the MCMC algorithm. Based on the genetic studies, the gene flow between the populations was calculated and potential migration routes were described. Dispersal models supplied by the CostDistance extension in ArcView Spatial Analyst were calculated for a 54.2 km² area in the “Freiburger Bucht”, comprising nine genetics sampling sites. First, Euclidean distances were calculated. Following this, three cost matrices were created für the study area: “historic land use” – based on a historic map from the 1850s – “generalised recent land use” – based on ATKIS land use data scaled down to the historic land use map – and “recent land use”, a more sophisticated model. All three models were combined with topographic surface data. The “Isolation by Distance Web Service” was then used to quantify the level of correlation between genetic distances and Euclidean respectively cost distances. The level of correlation rose in the order given above, with only the “recent land use” cost matrix yielding cost distances that were correlated with genetic distances on a significant level.
In order to quantify the outcome of sperm competition in the mating system of the rove beetle Ale... more In order to quantify the outcome of sperm competition in the mating system of the rove beetle Aleochara curtula we performed three different mating experiment series. Paternity was established by DNA fingerprinting with oligonucleo(ide probes. We found a precedence of the last male with a proportion of eggs fathered by the last male of 87% (median). Nevertheless, we observed a large variation of P2-values in A. curtilla and cases of mixed paternity were documented as well as cases of 100% or 0% paternity of the last male. The variation of P2-values correlates with the efficiency of spermatophore and sperm transfer.
Odonata of the 'Seewinkel' at Lake Neusiedl, Austria: Frequency, population trends, and how endan... more Odonata of the 'Seewinkel' at Lake Neusiedl, Austria: Frequency, population trends, and how endangered they are In the 'Seewinkel' area, east of Lake Neusiedl, 49 odonate species have been hitherto recorded. Of special importance is the autochthonous occurrence of Lestes macrostigma. The population trends of the various Odonata species have been analysed since 1 970, and the species are classified in categories of how endangered they are in terms of a Red List, according to the criteria of the German Federal Agency for Nature Conservation. Recently, the species from the 'Lacken' — characteristic, temporary shallow pools With a high soda concentration — have become especially endangered. On the other hand, the species that chiefly live in secondary habitats fike drains, ditches and gravel pits Show positive population trends. These species benefit from the improvement of water and habitat quality.
Details are given on 51 species of dragonflies concerning their distribution, habitats, abundance... more Details are given on 51 species of dragonflies concerning their distribution, habitats, abundance and time of flight in western Lower Saxony (GFR). Of particular interest are the records of indigenous populations of Sympecma paedisca Brauer, Aeshna viridis Eversm., Aeshna isosceles (Müller), Libellula fulva Müller and Sympetrum depressiusculum (Selys) as well as the occurrence of single individuals of Calopteryx virgo (L), Anax parthenope Selys, Cordulegaster boltoni (Don.) and Sympetrum pedemontanum (Allioni).
Population trends of the Odonata of the "Seewinkel" at Lake Neusiedl, Austria-The population tren... more Population trends of the Odonata of the "Seewinkel" at Lake Neusiedl, Austria-The population trends of all local Odonata species have been analyzed since 1970. The species are classified in categories of how endangered they are in terms of a Red List, according to the criteria of the German Federal Agency for Nature Conservation. In the "Seewinkel" area, east of Lake Neusiedl, 51 odonate species have been hitherto recorded. Of special importance is the autochthonous occurrence of Lestes macrostigma. The species are categorized in terms of their specific habitat selection in view of their life cycles. Recently, the species from temporary ponds, particularly the "Lacken"-characteristic, temporary shallow pools with a high soda concentration-have become especially endangered. On the other hand, the species that chiefly colonize secondary habitats like drains, ditches, and gravel pits show positive population trends. These species benefit from the improvement of water and habitat quality. Zusammenfassung Wir analysierten die Bestandsentwicklung der Libellen im Seewinkel/Neusiedler See seit 1970 und beurteilten ihre Gefährdung im Sinne einer Roten Liste gemäß dem Kriteriensys-tem des Bundesamtes für Naturschutz in Deutschland. Im Gebiet des Seewinkels östlich des Neusiedler Sees in Österreich wurden bislang 51 Libellenarten nachgewiesen. Beson-dere Bedeutung kommt dabei dem autochthonen Vorkommen von Lestes macrostigma zu. Wir versuchen, die Arten entsprechend ihrem Vorkommen in der Naturlandschaft nach Habitaten zu kategorisieren. Aktuell sind besonders die Libellenarten der temporären Ge-wässer, speziell der Lacken-die für das Gebiet charakteristischen, temporären Flachge-wässer mit hohem Sodagehalt-stark gefährdet. Dagegen zeigen sich positive Bestands entwicklungen bei den Libellen, deren Verbreitungsschwerpunkt im Gebiet an Sekundär-gewässern wie Gräben, Kanälen und Kiesgruben liegt. Die Arten profitieren dort von einer Verbesserung der Wassergüte und Habitatqualität.
The parasitic water mite Arrenurus papillator on the wings of Sympetrum fonscolombii (Acari; Odon... more The parasitic water mite Arrenurus papillator on the wings of Sympetrum fonscolombii (Acari; Odonata): a review with recent data-The red larvae of the water mite A. papillator are characteristic and easily visible feature on the wings of S. meridionale in central Europe. The attachment of water mites to odonate wings also occurs in other Sympetrum species, especially S. fonscolombii. The aim of this study is to analyse the relatively rare cases in S. fonscolombii recorded from the well-documented influx into Germany in 2015.
In order to quantify the outcome of sperm competition in the mating system of the rove beetle Ale... more In order to quantify the outcome of sperm competition in the mating system of the rove beetle Aleochara curtula we performed three different mating experiment series. Paternity was establishedby DNA ngerprintingwith oligonucleotideprobes. We found a precedence of the last male with a proportion of eggs fathered by the last male of 87% (median). Nevertheless, we observed a large variation of P 2-values in A. curtula and cases of mixed paternity were documented as well as cases of 100% or 0% paternity of the last male. The variation of P 2-values correlates with the ef ciency of spermatophore and sperm transfer.
Somatochlora arctica ist eine hochspezialisierte Spezies, die sich ausschließlich in Kleinstgewäs... more Somatochlora arctica ist eine hochspezialisierte Spezies, die sich ausschließlich in Kleinstgewässern in Mooren unterschiedlicher Art reproduziert. Ihre Larven ertragen sowohl das vorübergehende Austrocknen als auch das Durchfrieren ihrer Gewässer und sind in diesen häufig die einzigen Vertreter der Libellen. Da sowohl die Reproduktionsgewässer als auch die Lebensweise der Art unauffällig sind, ist der Nachweis schwieriger als bei den meisten anderen Arten und gelingt oft nur zufällig. Es ist deshalb davon auszugehen, dass S. arctica im Gebiet weiter verbreitet ist als bislang bekannt. Das Ausmaß der Auswirkungen der extrem trockenen Sommer 2018-2020 kann derzeit noch nicht landesweit eingeschätzt werden, aber zumindest für den Harz ist ein deutlicher Einbruch der Emergenzen belegt. Verbreitung Die eurosibirisch verbreitete Art zeigt innerhalb Europas einen deutlichen Schwerpunkt in der Mitte und im Norden und ist im Süden auf wenige Gebirge beschränkt (Boudot & Karjalainen in Boudot & KalKman 2015: 237-238). In Deutschland ist sie insgesamt sehr lückig verbreitet und hat ihre Siedlungsschwerpunkte in moorreichen Landschaften; innerhalb des Tieflands ist ihr bundesweiter Schwerpunkt im östlichen Niedersachsen (Baumann, BrocKhaus, clausnitzer & ott in BrocKhaus et al. 2015: 238-239).
Details are given on 51 species of dragonflies concerning their distribution, habitats, abundance... more Details are given on 51 species of dragonflies concerning their distribution, habitats, abundance and time of flight in western Lower Saxony (GFR). Of particular interest are the records of indigenous populations of Sympecma paedisca Brauer, Aeshna viridis Eversm., Aeshna isosceles (Müller), Libellula fulva Müller and Sympetrum depressiusculum (Selys) as well as the occurrence of single individuals of Calopteryx virgo (L), Anax parthenope Selys, Cordulegaster boltoni (Don.) and Sympetrum pedemontanum (Allioni).
Durch Torfabbau und Entwässerung war der Libellenbestand des Roten Moores in der hessischen Hochr... more Durch Torfabbau und Entwässerung war der Libellenbestand des Roten Moores in der hessischen Hochrhön akut bedroht. Im Rahmen von Pflegemaßnahmen wurden 1984 die Gräben im Hochmoorbereich angestaut sowie weitere Gewässer auf abgetorften Flächen geschaffen. Diese neu geschaffenen Lebensräume sowie ältere bereits bestehende Weiher am Moorrand wurden 1987/88 auf ihre Libellenfauna hin untersucht. Für das Rote Moor konnten 18 aktuell bodenstendiqe Libellenarten nachgewiesen werden. Die meisten dieser Arten besiedeln die Randbereiche. Doch konnten mit Leucorrhinia dubia, Aeshna juncea, Somatochlora arctica sowie Leucorrhinia pectoralis und Coenagrion hastulatum seltene und gefährdete Arten im Hochmoorbereich nachgewiesen werden. Ausgehend von kleinen Restpopulationen konnten sich besonders Leucorrhinia dubia und Aeshna juncea wieder im Hochmoorbereich in den neugeschaffenen Lebensräumen ausbreiten. Die aktuelle Libellenfauna wird mit dem benachbarten, relativ ungestörten Schwarzen Moor ve...
In order to quantify the outcome of sperm competition in the mating system of the rove beetle Ale... more In order to quantify the outcome of sperm competition in the mating system of the rove beetle Aleochara curtula we performed three different mating experiment series. Paternity was established by DNA fingerprinting with oligonucleotide probes. We found a precedence of the last male with a proportion of eggs fathered by the last male of 87% (median). Nevertheless, we observed a large variation of P2-values in A. curtula and cases of mixed paternity were documented as well as cases of 100% or 0% paternity of the last male. The variation of P2-values correlates with the efficiency of spermatophore and sperm transfer.
Aim: Recent studies suggest insect declines in parts of Europe; however, the generality of these ... more Aim: Recent studies suggest insect declines in parts of Europe; however, the generality of these trends across different taxa and regions remains unclear. Standardized data are not available to assess large-scale, long-term changes for most insect groups but opportunistic citizen science data is widespread for some. Here, we took advantage of citizen science data to investigate distributional changes of Odonata. Location: Germany Methods: We compiled over 1 million occurrence records from different regional databases. We used occupancy-detection models to account for imperfect detection and estimate annual distributions for each species during 1980–2016 within 5 x 5 km quadrants. We also compiled data on species attributes that were hypothesized to affect species' sensitivity to different drivers and related them to the changes in species' distributions. We further developed a novel approach to cluster groups of species with similar patterns of distributional change to repre...
The invasion of Sympetrum fonscolombii into Baden-Württemberg in 2015 (Odonata: Libellulidae)-In ... more The invasion of Sympetrum fonscolombii into Baden-Württemberg in 2015 (Odonata: Libellulidae)-In the federal state of Baden-Württemberg (southwestern Germany) 105 records of Sympetrum fonscolombii from 72 localities were recorded in 2015. The focus of the immigration was placed in the Upper Rhine valley. Successful reproduction of the summer generation in view of permanent colonization of Baden-Württemberg is discussed.
studies on the impact of habitat fragmentation on Coenagrion mercuriale
using genetic methods by... more studies on the impact of habitat fragmentation on Coenagrion mercuriale using genetic methods by microsatellite analysis and GIS models in BadenWürttemberg – Microsatellites are highly variable non-coding genomic regions that are inherited like alleles and therefore can be used for population studies. Genomic DNA, taken from 32 occurrences of the species, was isolated from leg samples of C. mercuriale and amplified by the polymerase chain reaction (PCR). Thirteen microsatellite loci were synthesized by use of specific primers flanking these microsatellite regions according to a standard protocol. These amplification products were separated by length by capillary electrophoresis and assigned to discrete „alleles“. The variability of these DNA sections at the investigated occurrences forms the basis for the statistical evaluations. A range from 0.425 to 0.591 was determined for the expected heterozygosity (He) as a degree for genetic diversity in the study area. The allele number per locus (Na) fluctuated between 2.71 and 4.86. The values within the core zone (patch 2) were relatively constant (He = 0.482-0.541; Na = 4.0-4.8), whereas larger fluctuations were measured in the isolated patches. There was no clear evidence of a bottleneck. The genetic differentiation (calculated as FST/1–FST) is small overall in the study area but increases with distance (isolation by distance; IBD). Values from 0.002 to 0.071 were determined for populations less than five km, and values between 0.006 and 0.205 over 20 km apart. The proportion of migrants was estimated using the MCMC algorithm. Based on the genetic studies, the gene flow between the populations was calculated and potential migration routes were described. Dispersal models supplied by the CostDistance extension in ArcView Spatial Analyst were calculated for a 54.2 km² area in the “Freiburger Bucht”, comprising nine genetics sampling sites. First, Euclidean distances were calculated. Following this, three cost matrices were created für the study area: “historic land use” – based on a historic map from the 1850s – “generalised recent land use” – based on ATKIS land use data scaled down to the historic land use map – and “recent land use”, a more sophisticated model. All three models were combined with topographic surface data. The “Isolation by Distance Web Service” was then used to quantify the level of correlation between genetic distances and Euclidean respectively cost distances. The level of correlation rose in the order given above, with only the “recent land use” cost matrix yielding cost distances that were correlated with genetic distances on a significant level.
In order to quantify the outcome of sperm competition in the mating system of the rove beetle Ale... more In order to quantify the outcome of sperm competition in the mating system of the rove beetle Aleochara curtula we performed three different mating experiment series. Paternity was established by DNA fingerprinting with oligonucleo(ide probes. We found a precedence of the last male with a proportion of eggs fathered by the last male of 87% (median). Nevertheless, we observed a large variation of P2-values in A. curtilla and cases of mixed paternity were documented as well as cases of 100% or 0% paternity of the last male. The variation of P2-values correlates with the efficiency of spermatophore and sperm transfer.
Odonata of the 'Seewinkel' at Lake Neusiedl, Austria: Frequency, population trends, and how endan... more Odonata of the 'Seewinkel' at Lake Neusiedl, Austria: Frequency, population trends, and how endangered they are In the 'Seewinkel' area, east of Lake Neusiedl, 49 odonate species have been hitherto recorded. Of special importance is the autochthonous occurrence of Lestes macrostigma. The population trends of the various Odonata species have been analysed since 1 970, and the species are classified in categories of how endangered they are in terms of a Red List, according to the criteria of the German Federal Agency for Nature Conservation. Recently, the species from the 'Lacken' — characteristic, temporary shallow pools With a high soda concentration — have become especially endangered. On the other hand, the species that chiefly live in secondary habitats fike drains, ditches and gravel pits Show positive population trends. These species benefit from the improvement of water and habitat quality.
Details are given on 51 species of dragonflies concerning their distribution, habitats, abundance... more Details are given on 51 species of dragonflies concerning their distribution, habitats, abundance and time of flight in western Lower Saxony (GFR). Of particular interest are the records of indigenous populations of Sympecma paedisca Brauer, Aeshna viridis Eversm., Aeshna isosceles (Müller), Libellula fulva Müller and Sympetrum depressiusculum (Selys) as well as the occurrence of single individuals of Calopteryx virgo (L), Anax parthenope Selys, Cordulegaster boltoni (Don.) and Sympetrum pedemontanum (Allioni).
Population trends of the Odonata of the "Seewinkel" at Lake Neusiedl, Austria-The population tren... more Population trends of the Odonata of the "Seewinkel" at Lake Neusiedl, Austria-The population trends of all local Odonata species have been analyzed since 1970. The species are classified in categories of how endangered they are in terms of a Red List, according to the criteria of the German Federal Agency for Nature Conservation. In the "Seewinkel" area, east of Lake Neusiedl, 51 odonate species have been hitherto recorded. Of special importance is the autochthonous occurrence of Lestes macrostigma. The species are categorized in terms of their specific habitat selection in view of their life cycles. Recently, the species from temporary ponds, particularly the "Lacken"-characteristic, temporary shallow pools with a high soda concentration-have become especially endangered. On the other hand, the species that chiefly colonize secondary habitats like drains, ditches, and gravel pits show positive population trends. These species benefit from the improvement of water and habitat quality. Zusammenfassung Wir analysierten die Bestandsentwicklung der Libellen im Seewinkel/Neusiedler See seit 1970 und beurteilten ihre Gefährdung im Sinne einer Roten Liste gemäß dem Kriteriensys-tem des Bundesamtes für Naturschutz in Deutschland. Im Gebiet des Seewinkels östlich des Neusiedler Sees in Österreich wurden bislang 51 Libellenarten nachgewiesen. Beson-dere Bedeutung kommt dabei dem autochthonen Vorkommen von Lestes macrostigma zu. Wir versuchen, die Arten entsprechend ihrem Vorkommen in der Naturlandschaft nach Habitaten zu kategorisieren. Aktuell sind besonders die Libellenarten der temporären Ge-wässer, speziell der Lacken-die für das Gebiet charakteristischen, temporären Flachge-wässer mit hohem Sodagehalt-stark gefährdet. Dagegen zeigen sich positive Bestands entwicklungen bei den Libellen, deren Verbreitungsschwerpunkt im Gebiet an Sekundär-gewässern wie Gräben, Kanälen und Kiesgruben liegt. Die Arten profitieren dort von einer Verbesserung der Wassergüte und Habitatqualität.
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Papers by Theodor Benken
using genetic methods by microsatellite analysis and GIS models in BadenWürttemberg – Microsatellites are highly
variable non-coding genomic regions that
are inherited like alleles and therefore can
be used for population studies. Genomic
DNA, taken from 32 occurrences of the
species, was isolated from leg samples of
C. mercuriale and amplified by the polymerase chain reaction (PCR). Thirteen
microsatellite loci were synthesized by
use of specific primers flanking these
microsatellite regions according to a standard protocol. These amplification products were separated by length by capillary
electrophoresis and assigned to discrete
„alleles“. The variability of these DNA
sections at the investigated occurrences
forms the basis for the statistical evaluations. A range from 0.425 to 0.591 was
determined for the expected heterozygosity (He) as a degree for genetic diversity
in the study area. The allele number per
locus (Na) fluctuated between 2.71 and
4.86. The values within the core zone
(patch 2) were relatively constant (He =
0.482-0.541; Na = 4.0-4.8), whereas larger
fluctuations were measured in the isolated patches. There was no clear evidence
of a bottleneck. The genetic differentiation (calculated as FST/1–FST) is small
overall in the study area but increases
with distance (isolation by distance; IBD).
Values from 0.002 to 0.071 were determined for populations less than five km,
and values between 0.006 and 0.205 over
20 km apart. The proportion of migrants
was estimated using the MCMC algorithm. Based on the genetic studies, the
gene flow between the populations was
calculated and potential migration routes
were described.
Dispersal models supplied by the CostDistance extension in ArcView Spatial Analyst were calculated for a 54.2 km² area in
the “Freiburger Bucht”, comprising nine
genetics sampling sites. First, Euclidean
distances were calculated. Following this,
three cost matrices were created für the
study area: “historic land use” – based on
a historic map from the 1850s – “generalised recent land use” – based on ATKIS
land use data scaled down to the historic
land use map – and “recent land use”,
a more sophisticated model. All three
models were combined with topographic
surface data. The “Isolation by Distance
Web Service” was then used to quantify
the level of correlation between genetic
distances and Euclidean respectively cost
distances. The level of correlation rose
in the order given above, with only the
“recent land use” cost matrix yielding
cost distances that were correlated with
genetic distances on a significant level.
using genetic methods by microsatellite analysis and GIS models in BadenWürttemberg – Microsatellites are highly
variable non-coding genomic regions that
are inherited like alleles and therefore can
be used for population studies. Genomic
DNA, taken from 32 occurrences of the
species, was isolated from leg samples of
C. mercuriale and amplified by the polymerase chain reaction (PCR). Thirteen
microsatellite loci were synthesized by
use of specific primers flanking these
microsatellite regions according to a standard protocol. These amplification products were separated by length by capillary
electrophoresis and assigned to discrete
„alleles“. The variability of these DNA
sections at the investigated occurrences
forms the basis for the statistical evaluations. A range from 0.425 to 0.591 was
determined for the expected heterozygosity (He) as a degree for genetic diversity
in the study area. The allele number per
locus (Na) fluctuated between 2.71 and
4.86. The values within the core zone
(patch 2) were relatively constant (He =
0.482-0.541; Na = 4.0-4.8), whereas larger
fluctuations were measured in the isolated patches. There was no clear evidence
of a bottleneck. The genetic differentiation (calculated as FST/1–FST) is small
overall in the study area but increases
with distance (isolation by distance; IBD).
Values from 0.002 to 0.071 were determined for populations less than five km,
and values between 0.006 and 0.205 over
20 km apart. The proportion of migrants
was estimated using the MCMC algorithm. Based on the genetic studies, the
gene flow between the populations was
calculated and potential migration routes
were described.
Dispersal models supplied by the CostDistance extension in ArcView Spatial Analyst were calculated for a 54.2 km² area in
the “Freiburger Bucht”, comprising nine
genetics sampling sites. First, Euclidean
distances were calculated. Following this,
three cost matrices were created für the
study area: “historic land use” – based on
a historic map from the 1850s – “generalised recent land use” – based on ATKIS
land use data scaled down to the historic
land use map – and “recent land use”,
a more sophisticated model. All three
models were combined with topographic
surface data. The “Isolation by Distance
Web Service” was then used to quantify
the level of correlation between genetic
distances and Euclidean respectively cost
distances. The level of correlation rose
in the order given above, with only the
“recent land use” cost matrix yielding
cost distances that were correlated with
genetic distances on a significant level.