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Survey Details for CNWLH071 - 2026-06-04

CNWLH071

Landscape Habitats

Llyn Alwen

Conwy

2008-11-03

  • Level 1: Wet Terrestrial Habitats
  • Level 2: Open Water
  • Level 3: Reservoirs & Lakes & Margines

Monitoring

Q1 - Date of monitoring?

  • 2016-01-15

Q1a - Monitoring undertaken by

  • Stages 1, 2 and 3 change detection, field verification and amendment completed by Environment Systems in conjunction with the local planning authority. Quality Assurance completed by TACP.

Q1b - Has this record been updated following monitoring work?

  • This record has been updated following monitoring work as more up to date information is available

Q1c - Change indicated by

  • OS Data, Aerial Photographs
  • Policies, plans & information resources

Q1d - What has changed?

  • Evaluation

Q1e - Has the information ever been verified in the field?

  • No

Q2 - Does this area have a special or functional link with an adjacent area?

  • Yes
    • The lake is the source of the Afon Aled, it is an important part of the ecosystem of CNWLH053 Mynydd Hiraethog upland mosaic.

Q3 - What is the total land area within the boundary (in hectares)?

  • 27ha

Description

Q4 - What are the dominant soil types? (specify up to 3 types)

  • Surface-water gley soils
  • Peat soils

Q5 - What Phase 1 habitat types are present? Only select the five most dominant types and, for each of these, specify below what percentage of the Aspect Area is made up of these.

  • Standing Water
    • 100%

Q6 - Does the area contain habitats of international importance?

  • Yes

Q7 - If yes, which habitats of international importance?

  • Clear water lakes with aquatic vegetation and poor to moderate nutrient levels

Q8 - Does the area contain BAP habitats?

  • Yes

Q9 - If yes, which BAP habitats?

  • Oligotrophic Lochs & Lakes

Q10 - Does the area contain protected sites?

  • Yes
    • SSSI(26.64ha)

Q11 - If yes, which ones?

  • SSSI

Q12 - Approximately what proportion of the Aspect Area is within the protected site?

  • 91-100%
    • 100%

Q13 - Does the area support important species?

  • Yes

Q14 - If yes, which species? (for each of the species, also note the source of information)

  • It supports water lobelia Lobelia dortmanna, rare elsewhere in the county, the water is important for the upland birds which use the moor including a large colony of black-headed gulls .

Q15 - Are there any significant threat species present in abundance? (Field visit required)

  • Not known

Q16 - What other features significantly influence the biodiversity in this area?

  • No Answer

Q17 - Are any of these features in a very good condition? (Field visit required)

  • No Answer

Q18 - Are any of these features in a poor condition? (Field visit required)

  • No Answer

Q19 - What are the main land management activities taking place in the area? (Field visit required)

  • No Answer

Q20 - Do any of the above appear to have an appreciable positive impact on biodiversity? (Field visit required)

  • No Answer

Q21 - Do any of the above appear to have an appreciable negative impact on biodiversity? (Field visit required)

  • No Answer

Q22 - Is the biodiversity in the area in any way threatened?

  • Not known

Q23 - Are there clear opportunities to improve the biodiversity aspect of this area?

  • Yes
    • Opportunities in management of surrounding terrestrial habitats

Q24 - Summarise the key features that define this area's biodiversity character

  • A natural oligotrophic lake within the Mynydd Hiraethog moors, and the source of the Afon Aled, supporting plant species characteristic of nutrient-poor status, such as quillwort and water lobelia, with some wildfowl.

Condition

Q25 - Value

  • High
    • The lake has a low nutrient-poor status restricting the diversity of species, but some of those present are rare elsewhere in the county. It forms an important part of the wider ecosystem and has therefore been awarded a high evaluation.

Q26 - Condition

  • Unassessed

Q27 - Trend

  • Constant

Recommendations

Q28 - Existing management

  • Unassessed

Q29 - Existing management remarks:

  • The lake is not managed.

Q30 - Principal management recommendations

  • NA

Q31 - Guideline

  • No Answer

Aspect Area Boundary

Q32 - To what level was this information site-surveyed?

  • Level 3

Q33 - At 1:10,000, how much of the Aspect Area boundary is precise?

  • All

Q34 - What baseline information source was used for Aspect Area boundary mapping?

  • Aerial photographs

Q35 - If OS Data was used, what was the scale?

  • 1:10,000

Q36 - What is the justification for the Aspect Area boundaries?

  • The Aspect Area follows the edge of the lake.

Evaluation

Q37 - Evaluation Criteria: Priority Habitats

  • High
    • A natural oligotrophic lake which itself is part of a larger ecosystem that supports important upland species.

Q38 - Evaluation Criteria: Significance

  • Moderate
    • Although this lake is not of national importance on its own, when view with the surrounding Aspect areas it represents part of important habitat features.

Q39 - Evaluation Criteria: Opportunity

  • Moderate
    • Management of surrounding land affects inputs into existing habitat resource

Q40 - Evaluation Criteria: Expansion rates

  • Unassessed

Q41 - Evaluation Criteria: Sensitivity

  • Moderate
    • There is no significant evidence of threats

Q42 - Evaluation Criteria: Connectivity/Cohesion

  • Outstanding
    • Part of a large upland mosaic of internationally important habitats

Q43 - Evaluation Criteria: Habitat Evaluation

  • Moderate
    • Although this is a small area its an important lake in a matrix of internationally important upland habitats

Q44 - Evaluation Criteria: Importance for key species

  • Unassessed

Q45 - Evaluation Criteria: Overall Evaluation Habitat and Species

  • High
    • The species data sows it supports uncommon species this together with the fact that it forms a significant part of an upland ecosystem gives it a moderate to high evaluation.

Q45a - Justification of overall evaluation

  • The lake has a low nutrient-poor status restricting the diversity of species, but some of those present are rare elsewhere in the county. It forms an important part of the wider ecosystem and has therefore been awarded a high evaluation.

Bibliography

Q46 - Sources and additional assessments

  • Vexcel 2006 aerial photography, Getmapping - Millenium Map digital aerial photography. CCW - Phase 1 Habitat vector GIS data set. Countryside Council for Wales Species Information, CCW SSSI Notification sheets for Ceredigion.

Assessment

Q47 - Additional Assessments

  • A natural oligotrophic lake within the Mynydd Hiraethog moors.

Q48 - Additional Comments

  • Species records used in the study are not comprehensive and the absence of species in an area may well be an indication of incomplete records rather than a true lack. Land managers, developers, planners and other land users will need to satisfy themselves as to the occurrence of such species within the area if existing land management or management changes might affect these species in the future. A first step to procuring this data will be to consult with the local biodiversity records centre.