Article 17 web tool

Scientific name used in original MS report if different than recommended: "Najas flexilis"
Information provided in the field 2.8.2: Reported additionnal information: ||
->Range: N/A ||
->Population: N/A ||
->HabInfo: N/A ||
->Future: N/A ||
->Conclusion: In 2002, Najas flexilis was discovered in lake Millstätter See during an extended macrophyte-mapping campaign according to the Water Framework Directive. The species was not yet reported in the 2007 and 2013 report. ||
->JustificationThreshold: N/A ||
->Other: N/A

Open Original Report  

Scientific name used in original MS report if different than recommended: "Najas flexilis"
Information provided in the field 2.8.2: Reported additionnal information: ||
->Range: The favourable reference range of the species is considered to be larger than the present range, due to earlier observations. ||
->Population: N/A ||
->HabInfo: N/A ||
->Future: N/A ||
->Conclusion: N/A ||
->JustificationThreshold: N/A ||
->Other: N/A

Open Original Report  

Scientific name used in original MS report if different than recommended: "Najas flexilis"
Information provided in the field 2.8.2: Reported additionnal information: ||
->Range: The 52 lake polygons produced a 10 km grid distribution of 39 squares that was used to calculate the range of 5,900 km2, using the range tool.
The range has reduced by 800 km2 since the last reporting cycle. The recorded extinctions at three additional lakes led to a 400 km2 reduction in range (genuine change). The range decreased by 500 km2 as a result of the rejection of records for Lough Derg, Lough Adoolig, Lough Illauntrasna, Lough Sruffauncam and Fin Lough (improved knowledge). The discovery of the species at Knocka Lough, Co. Clare increased the range by 100 km2 (R16). The four other previously undocumented populations discovered were within the previous range.
The short- and long-term trends were based on population extinctions. The species is considered to have gone extinct from a total of six lakes. Two (Keel and Glenade) of these six extinctions were considered to have occurred since the Directive came into force. In addition, the status of the species in at least two lakes (Corrib and Kylemore) is uncertain: the populations may be extinct, however further survey is required. ||
->Population: The required population size reporting unit was calculated by selecting all 1 x 1 km grid squares containing point records for the 52 extant populations.
The additional population unit was given as the number of localities, where one locality is one lake.
The 1 x 1 km grid squares unit is not a reliable, repeatable measure as point records are observations in space and time and reflect the distribution of survey effort rather than the species itself. Furthermore, the seasonality of Najas flexilis means that failures to observe the species cannot be interpreted as an absence of the species, while the challenges of underwater survey mean that the full extent of a population can seldom be recorded (see O Connor, 2013). As a result, the 1 x 1 km grid squares estimate is considered to be a minimum population size.
The new, required reporting unit 1 x 1 km grid squares is not comparable with previous reports (leading to a change between reporting periods owing to the use of a different method).
Given the practical challenges and high uncertainty in estimating the size of Najas flexilis populations (see O Connor, 2013), it is not possible to report trend magnitudes.
Trends were based on recorded decreases in population (number of locations in a lake, area of occupancy, depth range, numbers of plants, density of plants). Four of the six declared extinctions occurred outside of the trend periods (i.e. before 1994) and were not considered. Data were available for 32 populations in two time periods – typically 2000-2005 (Roden, 1999, 2002, 2003, 2004, 2005, 2007) and 2013-2018 (Roden and Murphy, 2014; Roden et al., 2016, 2017, 2018, in prep.). 20 of the 32 populations were considered to be ‘stable’ between the periods, 11 were considered to be ‘decreasing’ and one was categorised as ‘uncertain’.
Uncertainty is high in assessing changes in population for this annual species, as illustrated by the lake categorised as ‘uncertain’, Loch an Chaolaigh, which was surveyed annually between 2016 and 2018. The species was recorded in 2017, but was absent in 2016 and 2018.
No populations were assessed as ‘increasing’, although some recovery may have occurred at one lake, Tully Lough.
Overall, 9 out of 30 populations, or 30%, were assessed as ‘decreasing’. This is likely to be an underestimate as ‘stable’ was the default assessment.
Changes between reporting periods resulted from the change in reporting unit (from numbers of mature individuals to 1 x 1 km grid squares), improved data from surveys during the reporting cycle and genuine, documented decreases in Najas flexilis populations. ||
->HabInfo: The Slender Naiad grows permanently submerged, commonly at depth, in clear-water, lowland lakes. In Ireland, it is associated with the Habitats Directive Annex I habitat 3130 (Oligotrophic to mesotrophic standing waters with vegetation of the Littorelletea uniflorae and/or Isoeto-Nanojuncetea).
Information on the condition of the Najas flexilis habitat was available for 33 lakes (Roden and Murphy, 2014; Roden et al., 2016, 2017, 2018, in prep.). 20 lakes were assessed as in Good habitat condition, ten as Poor/Unfavourable-Inadequate and three as Bad/Unfavourable-Bad. This equates to 61% of sites in Good condition, 30% Poor and 9% Bad.
As for the 2000-2006 and 2007-2012 cycles, habitat area was based on the entire surface area of the lake. 1:5,000 OSi data were used. For Lough Corrib, only the north-western basin was included (4.96 km2). The total area of the habitat for 2013-2018 was estimated as 48.25 km2. In terms of habitat (lake) area, therefore, 10.47 km2 (or 22%) was in Good condition, 28.7 km2 (or 59%) was Poor, 5.65 km2 (or 12%) Bad and 3.44 km2 (or 7%) Unknown.
In order for Najas flexilis to maintain itself on a long-term basis as a viable component of its natural habitats, each occupied lake must have habitat in Favourable condition. Owing to the small size of most Najas flexilis lakes, natural mixing and associated processes, for many sites, the entire lake must reach the required habitat targets.
The condition of the habitat was compared to data from earlier surveys in order to assess trends. Data were available for 30 Najas flexilis lakes in two time periods – typically 2000-2005 (Roden, 1999, 2002, 2003, 2004, 2005, 2007) and 2013-2018 (Roden and Murphy, 2014; Roden et al., 2016, 2017, 2018, in prep.). 22 of the 30 lakes were considered likely to have ‘stable’ habitat condition between the periods and eight were considered to be ‘decreasing’.
Owing to the limited number of samples over time, short- and long-term trends were assumed to be the same.
Where uncertainty was high, the default trend in habitat condition was assessed as ‘stable’. Therefore a ‘decreasing’ assessment required strong evidence of decline in habitat quality.
Impacts observed on the species’ habitat were eutrophication (epiphytic algae, phytoplankton blooms and increased perennial biomass); deposited, decomposing organic matter; reduced and fluctuating transparency/euphotic-depth (peat-staining and turbidity); and competition from Elodea canadensis.
For the 2000-2006 cycle the habitat area was reported as 49.60 km2 and in 2007-2012 it was 61.4 km2. Changes between reporting cycles were largely the result of improved knowledge of the species’ distribution (see above). The use of different mapping scales also resulted in small differences in the surface area of individual lakes.
For the 2007-2012 cycle, the assessment of habitat quality and trends was largely based on Irish EPA WFD lake status data. The use of dedicated Najas flexilis habitat condition assessments for the 2013-2018 cycle represents an improvement in knowledge.
EPA WFD status data (Fanning et al., 2017) were available for 17 of the lakes surveyed 2014-2018 (Roden and Murphy, 2014; Roden et al., 2016, 2017, 2018, in prep.). Adopting the interpretation of O Connor (2013), WFD data would indicate better condition at three lakes, the same condition at eight and worse at six lakes. ||
->Future: The Future prospects of the Range, Population and Habitat for the species were assessed by reference to Pressures and threats and Conservation measures, as well as each parameter’s ‘future trends’ and current status:
Pressures and threats: Five pressures of high importance were recorded and three of medium importance and all were listed as threats, owing to their likely continuation. These pressures and threats result in changes in hydrological regime and water quality and, therefore, have negative influence on the status of the habitat’s Structure and functions.
Conservation measures: No species-specific, concrete conservation measures are currently being undertaken to maintain, restore or enhance populations of Najas flexilis, either within SACs or the wider countryside. It will take time to identify conservation measures based on the ecological requirements of the species, combined with the site-specific conservation objectives, conditions and significant pressures and threats; and there is likely to be a time-lag before conservation measures, once implemented, take effect. Therefore, conservation measures will not halt or reverse the negative influence of the threats in the next 12 years.
Range: The short- and long-term trends of the Range were assessed as decreasing. The current range is 3% less than the Favourable Reference Range. Therefore, the Conservation Status of the Range was assessed as Unfavourable-Inadequate. Given the negative influence of the identified pressures and threats on the species populations and their habitat, and the lack of conservation measures, the predicted future trend in Range is negative. As a result, the Future prospects of the Range were assessed as poor.
Population: The short- and long-term trends of the Population were assessed as decreasing. The estimated minimum population is 3% smaller than the Favourable Reference Population. Therefore, the Conservation Status of the Population was assessed as Unfavourable-Inadequate. Given the negative influence of the identified pressures and threats on the species populations and their habitat, and the lack of conservation measures, the predicted future trend in Population is negative. As a result, the Future prospects of the Population were assessed as poor.
Habitat for the species: The short- and long-term trends in Habitat for the species were assessed as decreasing. Structure and functions was assessed as decreasing owing to evidence of habitat deterioration at eight of 30 lakes with data from two points in time. Habitat quality was Good at 20 lakes, Poor/Unfavourable-Inadequate at ten and Bad/Unfavourable-Bad at three. Recovery of good habitat quality is considered to be possible at the 13 lakes assessed as Unfavourable. As a result, the Conservation Status of the Habitat for the species was assessed as Unfavourable-Inadequate. Given the negative influence of the identified pressures and threats on the species populations and their habitat, and the lack of conservation measures, the predicted future trend in Habitat for the species is negative. As a result, the Future prospects of the Habitat for the species were assessed as poor.
As Future prospects of the three parameters were assessed as poor, the Future prospects for Najas flexilis were assessed as Unfavourable-Inadequate. ||
->Conclusion: Range:
Current range is 3% below the Favourable Reference Range;
Loss of 200 km2 since 1994 is <0.14% per year;
As a result, the Conservation Status of Range was assessed as Inadequate (U1).

Population:
Current population is 3% below the Favourable Reference Population;
9 of 30 populations were assessed as declining, with high uncertainty;
The size of population declines was unquantifiable;
There was no evidence to indicate a population decline of more than 1% per year;
As a result, the Conservation Status of Population was assessed as Inadequate (U1).

Habitat for the species:
Habitat quality was Good at 20 lakes, Poor/Unfavourable-Inadequate at ten and Bad/Unfavourable-Bad at three;
Recovery of good habitat quality is considered to be possible at the 13 lakes assessed as Unfavourable;
As a result, the Conservation Status of Habitat for the species was assessed as Inadequate (U1).

Future prospects:
In line with the other three parameters, the Conservation Status of Future prospects for Najas flexilis was assessed as Inadequate (U1).

Overall conservation status:
As all four parameters were assessed as Inadequate (U1), the Overall Conservation Status was assessed as Inadequate (U1).

The overall trend (qualifier) in Conservation Status was assessed as deteriorating, because the short- and long-term trends of Range, Population and Habitat for the species were assessed as ‘decreasing’ (sections 5.3, 5.7, 6.8, 6.12, 7.4 and 7.7), owing to two population extinctions, population decreases at a further nine lakes and decreasing habitat quality at eight lakes. In 2013, trends were assessed as stable owing to a lack of evidence of population extinctions or declines in habitat. As a result of the dedicated surveys during the current reporting cycle (2013-2018) (Roden and Murphy, 2014; Roden et al., 2016, 2017, 2018, in prep.), there are improved data to inform the trend assessments. The recent data (2013-2018) were compared to previous data available for the same sites – typically 2000-2005 (Roden, 1999, 2002, 2003, 2004, 2005, 2007). As data were available for only two points in time for most sites, it was not possible to identify when deterioration began or to determine whether it was on-going throughout the reporting cycle. ||
->JustificationThreshold: N/A ||
->Other: N/A

Open Original Report  

Scientific name used in original MS report if different than recommended: "Najas flexilis"
Information provided in the field 2.8.2: Reported additionnal information: ||
->Range: As a submerged Annual plant it is difficult to record systematically. Further, evidence shows that it can return a decade after it last set seed in significant numbers, complicating accurate recording. Several sites with records older than a decade have been removed from the range since 2013. This loss is balanced by the submission of eight additional sites to the records. ||
->Population: As an annual species occuring in deep water, with a population which fluctuates across years, estimating population size is difficult. However, the decline in population is since 2013 is considered genuine, with the population considered to have decreased by 1% or less per year across the current reporting period. ||
->HabInfo: The occupied habitat for the species is considered sufficient. However, despite improvements in water quality under the Water Framework Directive, the short term trend in quality of habitat is set decreasing due to acidification, nutrient enrichment and competition from non-native species in some loch habitats. ||
->Future: Future trend of Range is Negative - decreasing <=1% (one percent or less) per year on average; Future trend of Population is Overall stable; and Future trend of Habitat for the species is Positive - slight/moderate improvement. For further information on how future trends inform the Future Prospects conclusion see the 2019 Article 17 UK Approach document. ||
->Conclusion: Conclusion on Range reached because: (i) the short-term trend direction in Range surface area is stable; and (ii) the current Range surface area is not less than the Favourable Reference Range.

Conclusion on Population reached because: (i) the short-term trend direction in Population size is decreasing by 1% per year or less; and (ii) the current Population size is not more than 25% below the Favourable Reference Population.

Conclusion on Habitat for the species reached because: (i) the area of occupied habitat is sufficiently large and (ii) the habitat quality is suitable for the long-term survival of the species; and (iii) the short-term trend in area of habitat is decreasing.

Conclusion on Future prospects reached because: (i) the Future prospects for Range are poor; (ii) the Future prospects for Population are poor; and (iii) the Future prospects for Habitat for the species are poor.

Overall assessment of Conservation Status is Unfavourable-inadequate because three of the conclusions are Unfavourable-inadequate.

Overall trend in Conservation Status is based on the combination of the short-term trends for Range - stable, Population - decreasing, and Habitat for the species - decreasing.

Overall assessment of Conservation Status has not changed since 2013.

The Overall trend in Conservation Status has changed between 2013 and 2019 because the Habitat for the species trend has changed from stable to decreasing ||
->JustificationThreshold: N/A ||
->Other: N/A

Open Original Report  

Scientific name used in original MS report if different than recommended: "Najas flexilis"
Information provided in the field 2.8.2: Reported additionnal information: ||
->Range: N/A ||
->Population: N/A ||
->HabInfo: N/A ||
->Future: N/A ||
->Conclusion: N/A ||
->JustificationThreshold: N/A ||
->Other: N/A

Open Original Report  

Scientific name used in original MS report if different than recommended: "Najas flexilis"
Information provided in the field 2.8.2: Reported additionnal information: ||
->Range: N/A ||
->Population: N/A ||
->HabInfo: N/A ||
->Future: N/A ||
->Conclusion: N/A ||
->JustificationThreshold: N/A ||
->Other: N/A

Open Original Report  

Scientific name used in original MS report if different than recommended: "Najas flexilis"
Information provided in the field 2.8.2: Reported additionnal information: ||
->Range: N/A ||
->Population: This species was found in two lakes situated in the western and eastern parts of the country. The population in Lake Sągardas (Ignalina district) was rather sparse in both 1998 and 2015, while the population in Lake Germantas (Telšiai district) has not been found since 1966. ||
->HabInfo: N/A ||
->Future: N/A ||
->Conclusion: N/A ||
->JustificationThreshold: N/A ||
->Other: N/A

Open Original Report  

Scientific name used in original MS report if different than recommended: "Najas flexilis"
Information provided in the field 2.8.2: Reported additionnal information: ||
->Range: In Latvia N.flexilis is found in 11 lakes (locations in 2 lakes have been destroyed). Lake Sivers is considered to be the richest lake with N.flexilis, as in 2014 the species was discovered in 34 locations in the lake, but the number of locations might be larger. ||
->Population: During monitoring in 2015 the six previously known locations (lakes) with N. flexilis were observed. Only in one site species was found ( in N2000 site "Augšzeme", Lake Skujines). Lack of species in previously known localities can be explained by the species life cycle and probably later will be found as habitats are suitable.

Neverless in 2018 during EU habitat mapping species was recorded in Lake Dridzis. ||
->HabInfo: As during reporting period species was not found in 5 of 6 locations. There is need to do ecological studies, including the physico-chemical parameters of water that cannot be estimated visually, but which can be crucial to explain species habitat quality. Accordingly to U.Šuško research in Lake Ārdava (2013) the habitat available for species could be at least 800 - 1000 m2 in this lake, for other lakes specific species habitat aera han't been evaluated. ||
->Future: N/A ||
->Conclusion: N/A ||
->JustificationThreshold: Due to the anthropogenic eutrophication the population of Najas flexilis has been in bad condition in 2 lakes (Lake Salmejs and Lake Ārdavs) in previous report, currently there is no changes. Actually, one of these localities in Lake Ārdavs that was discovered for the first time in 2006, might be destroyed due to the species composition change and competition by extensive macrophyte species. Other lakes are in good and moderate quality, but species was not found during monitoring. ||
->Other: Najas flexilis is a relict species that is growing in clean (unpolluted) lakes with transparent water. It can also temporarily survive in moderately polluted lakes. However, if the pollution is too strong the species disappears and its locality is lost. Lake Usmas was the only one known locality of the species till 1994 when a new locality was discovered in Lake Skujines. From 2003 several new localities of the species have been discovered. There is a possibility to discover more localities, especially in lakes of South-east Latvia as only a small part of lake macrophyte flora and vegetation has been thoroughly investigated in Latvia.

Open Original Report  

Scientific name used in original MS report if different than recommended: "Najas flexilis"
Information provided in the field 2.8.2: Reported additionnal information: ||
->Range: ETC’s (2018) range tool was used to generate a standardized grid map and to calculate the range. Observations registered in the national species database Artportalen (www.artportalen.se) were used to assess the distribution of the species. Sites monitored by flora guardians are included in the database. Changes compared with previous assessments are primarily due to improved knowledge and/or more accurate data. ||
->Population: The current population size was estimated based on regional monitoring programmes. Most of the data has been accessed through the national database Artportalen (www.artportalen.se). Differences in population estimates between reporting periods are the result of more quantitative and accurate data. The overall trend appears to be stable. ||
->HabInfo: Expert opinion based on discussion with the reference group and experts at the Swedish Species Information Centre. The habitat for the species is assumed to be sufficient for a species when both the current population size is equal to the favourable reference population (FRP) and the population trend is stable. In the boreal region all parameters are assessed as FV since the populations seems to be stable and no apparent pressure or threat has been identified. The species naturally has very scattered occurrences in the boreal region and it has never been common. Furthermore, it is possible that Najas flexilis occurs at more sites in the region since it is difficult to find, water plants generally are poorly known and there should be many more lakes in the region with a suitable habitat. ||
->Future: The assessment of future prospect is equal to the overall current conservation status for all parameters combined. ||
->Conclusion: The overall assessment of conservation status was made following the evaluation matrix in the ETC Explanatory Notes & Guidelines. Changes compared with previous assessments are primarily due to improved knowledge and/or more accurate data. ||
->JustificationThreshold: N/A ||
->Other: N/A

Open Original Report  

Scientific name used in original MS report if different than recommended: "Najas flexilis"
Information provided in the field 2.8.2: Reported additionnal information: ||
->Range: ETC’s (2018) range tool was used to generate a standardized grid map and to calculate the range. Observations registered in the national species database Artportalen (www.artportalen.se) were used to assess the distribution of the species. Sites monitored by flora guardians are included in the database. Changes compared with previous assessments are primarily due to improved knowledge and/or more accurate data. ||
->Population: Population size was estimated based on regional monitoring programmes. Most of the data has been accessed through the national database Artportalen (www.artportalen.se). Differences in population estimates between reporting periods are the result of more quantitative and accurate data. The overall trend appears to be stable. ||
->HabInfo: Expert opinion based on the action plan for the species and discussion with the reference group and experts at the Swedish Species Information Centre. The species has an extremely scattered occurrence and the reason for this is not known. It might be due to very specific habitat requirements or incomplete dispersal. Furthermore, it is not known if the lakes where the it has occurred earlier nowadays have become suitable for the species again. There are only medium pressures & threats in the continental region. The habitat in Lake Hammarsjön is assessed as satisfying. The habitat in the lakes from which the species has disappeared has been improving a lot during the last 50 years but it is uncertain whether it is good enough for healthy populations of Najas flexilis. Consequently, the habitat for the species has been assessed as U1 in the continental region. ||
->Future: It is assumed that the implemented conservation measures are not wide-ranging enough to improve parameters assessed as ‘poor’ or ‘bad’ to ‘good’. Consequently, the assessment of future prospect is equal to the overall current conservation status for all parameters combined. The future prospect is assessed as U2 since it is not likely that the deficiency in range and population will change within the time frame used. ||
->Conclusion: The overall assessment of conservation status was made following the evaluation matrix in the ETC Explanatory Notes & Guidelines. Changes compared with previous assessments are primarily due to improved knowledge and/or more accurate data. ||
->JustificationThreshold: N/A ||
->Other: N/A

Open Original Report