The River Hun

A State of the Environment Report

Produced by Norfolk Biodiversity Information Service

Norfolk Biodiversity Information Service (NBIS) is a Local Record Centre holding information on species, geodiversity, habitats and protected sites for the county of Norfolk. For more information visit our website: www.nbis.org.uk

Report written by Liam Smith, March 2019

Acknowledgements The author would like to thank Lizzy Oddy for her help with producing the maps and data for this report.

Cover photo: © Copyright Mat Fascione and licensed for reuse under this Creative Commons Licence.

CONTENTS WELCOME…………………………………………………………………………………………….1 LANDSCAPE AND GEODIVERSITY………………………………………………………….2

Candidate County Geodiversity Sites……………………………………………………………2

DESIGNATED SITES……………………………………………………………………………………………..3

Site designations..………………………………………………………………………………………..3

North Norfolk Coast……………………………………………………………………………………..4

Holme Dunes………………………………………………………………………………………………..6

HABITATS AND LAND USE…………………………………………………………………………………9

Habitat and Land-Use mapping...... …...9

Unique Habitat Features………………………………………………………………………….….10

SPECIES…………………………………………………………………………………………………………….…..12

Species Records……………………………………………………………………………………….….12

Rare Species………………………………………………………………………………………….…….12

Notable Species……………………………………………………………………………………….….13

Non-Native Species……………………………………………………………………………..………13

Non-Native Flora……………………………………………………………………………………..….14 Non-Native Fauna………………………………………………………………………………………..14 Further Reading……………………………………………………………………………………………….…15

WELCOME The River Hun is a short chalk stream that runs just 6km from its source in Hunstanton Park to where it meets the North Sea at Holme Dune National Nature reserve. This state of the environment report will cover an area of 3.82 km2 adjacent to the river including reed beds, sand dunes, saline lagoons and a multitude of other habitats. This report will explain the geological features, flora and fauna that make the River Hun area an outstanding environment. An environment that has garnered national and international recognition and protection and has more valuable and diverse habitats than most other similarly sized areas.

The blue outline on the map above shows the boundary of the River Hun study area. The orange arrow shows the location of the River Hun which flows from the east to the west of the study area.

LANDSCAPE AND GEODIVERSITY

Candidate County Geodiversity Sites Candidate County Geodiversity Sites (cCGS) are local sites designated for their geodiversity interest. They are designated by the County Geodiversity Sites Group and are covered by DEFRA Local Sites policy guidance. There are 2 candidate County Geodiversity Sites within the River Hun study area. These are:

Site name Site description Geodiversity features North Norfolk Coastline with Nationally important example of coastal Coast SSSI geomorphological landform assemblage, comprising part of a (King's Lynn and features in King's 40km stretch of Holocene intertidal sands and West Norfolk Lynn and West muds, saltmarshes, shingle banks and sand District part) Norfolk District - dunes, and the shingle spit at Blakeney Point Holocene and the offshore shingle bank at Scolt Head. geomorphology

Holme Active coastal Sequence of Holocene terrestrial deposits Foreshore landforms - exposed on foreshore, including saltmarsh clays Holocene deposits overlain by reed swamp and alder carr peats of geomorphology and 4th millennium BP age; site of early Bronze Age archaeology ceremonial wooden structure 'Seahenge' excavated 1999 and other wooden structures including trackways.

Exposed Bronze age wooden structures © Copyright Julian Dowse and licensed for reuse under this Creative Commons Licence.

DESIGNATED SITES

Within the River Hun study area there are 2 designated statutory sites of importance and there are a further 2 that are adjoining the study area. These are:

Site name Designation North Norfolk Coast SSSI, SAC, SPA, Ramsar Holme Dunes National Nature Reserve The Wash and North Norfolk Coast (outside SAC study area)

The Greater Wash (outside study area) SPA

Site Designations

There are a number of designations that a site can be given in the UK, providing different levels of protection. For example, ‘statutory sites’ are protected by law in the planning process, while ‘non- statutory’ sites are not, although they are still recognised as important and taken into account in planning. The different levels of designation are summarised below:

Designation Description

Ramsar Site Statutory An internationally important wetland site, designated international under the RAMSAR CONVENTION.

Special Protection Statutory European designation for sites of international Area (SPA) international importance for birds.

Special Area of Statutory European protected site designated by the UK Conservation (SAC) international government. Sites of international importance under the EC HABITATS DIRECTIVE.

Site of Special Statutory Designated and protected by Natural England as the Scientific Interest national best sites for wildlife or geology in the country. (SSSI)

National Nature Statutory A site of national importance for nature conservation. Reserve (NNR) national Allow scientific research and most have at least some public access.

Local Nature Reserve Statutory local A site of special nature conservation interest locally, (LNR) designated by local authorities.

County Wildlife Site Non-statutory Sites outside of statutory protected areas but of wildlife (CWS) county importance at a county level.

North Norfolk Coast Designated as a SSSI, SAC, SPA and Ramsar site, the North Norfolk Coast is a highly designated and nationally and internationally important site. The geographical position and varied habitats make the North Norfolk Coast a valuable site for wading bird species and for overwintering migrants. A wide range of coastal plants are also represented in the area with many rare or locally endemic species having been recorded. Almost a half of the River Hun study area falls within the North Norfolk Coast designated area which covers the areas surrounding the saline lagoons and the mouth of the river (Figure 2, Figure 3). Site of Special Scientific Interest North Norfolk coast SSSI covers an area of 7,700 acres, running 40km between Hunstanton and Weybourne. The entire SSSI consists of 70 Units which are regularly assessed for their condition through Common Standards Monitoring. These conditions are explained below. Condition Meaning Favourable Habitats and features are in a healthy state and are being conserved by appropriate management Unfavourable If current management measures are sustained the site will (Recovering) recover over time Unfavourable (No Special features are not being conserved or are being lost, so Change) or without appropriate management the site will never reach a Unfavourable(Declining favourable or recovering condition Condition) Part destroyed or There has been fundamental damage, where special features have Destroyed been permanently lost and favourable condition can’t be achieved Of the 70 assessed units within the SSSI, 67 are categorised as in Favourable conditions whilst 3 are in Unfavourable recovering. Seven of the SSSIs are either completely or partially within the River Hun study area, 6 of which are in favourable condition whilst one is unfavourable recovering (Figure 1). The one unit that is in unfavourable recovering condition is Holme Bird Observatory. Scrub invasion has been identified as a potential threat to the site, along with the challenge of balancing the maintenance of the good quality dunes whilst also providing a percentage of scrub and tree cover to enable the bird ringing operations that are carried out there. Threats to the condition of the other SSSI units within the River Hun area were also noted in the condition assessments. The main concerns regarding the ongoing condition were erosion of sand dunes and scrub encroachment.

Sand Dunes at Holme NNR © Copyright Christine Matthews and licensed for reuse under this Creative Commons Licence.

Figure 1

SAC Almost half of the River Hun study area falls within the North Norfolk Coast Special Area of Conservation. The site was designated as an SAC due to several rare or important habitats and species. These are: Coastal lagoons, Perennial vegetation of stony banks, Mediterranean and thermo-Atlantic

Established Sand Dunes, North Norfolk Coast © Copyright Paul E halophilous scrubs (Sarcocornetea fruticosi), Smith and licensed for reuse under this Creative Commons Licence. embryonic shifting dunes, shifting dunes along the shoreline with Ammophila arenaria, fixed coastal dunes with herbaceous vegetation and humid dune slacks. Two features of the North Norfolk Coast SAC are found within the River Hun study area. These are humid dune slacks and nationally important embryonic shifting dunes. There are only 2 examples of embryonic shifting dunes in the east of England, those that encompass part of the River Hun Study area are graded A (outstanding examples of the feature in a European context.) SPA The North Norfolk Coast is designated as a Special Protection Area for its value to 11 Coastal/Marine bird species. Many of these species are migratory, some such as the Pink- footed goose use the area for overwintering whilst others migrate to the area to breed throughout summer. Five threats have been identified to the SPA area, these are: interspecific faunal relations, outdoor sports, leisure and recreational activities, fishing and harvesting aquatic resources, changes in biotic conditions and changes in abiotic conditions. Ramsar “The site is one of North Norfolk Coast was designated as a wetland of international importance on the Ramsar list. The habitats that the largest have been identified at the site which are of international importance for their fauna, flora and geomorphology are: examples of sandflats, sand dunes, saltmarsh, shingle and saline lagoons. undeveloped The North Norfolk Coast is also recognised for supporting at least 8 internationally significant populations of breeding and coastal habitat of overwintering birds. its type in Holme Dunes Europe.” The Holme Dunes National Nature Reserve surrounds the dunes and saline lagoons to the north of the River Hun Study area. The area is managed by Norfolk Wildlife Trust and although it is an important habitat for migrating and breeding coastal birds, the reserve also provides a home to other species of wildlife. This includes the natterjack toad and many rare moths, butterflies and plant species. The entire area of Holme dunes falls within North Norfolk Coast SSSI.

Figure 2

Figure 3

HABITATS AND LAND USE

Habitat and Land-Use Mapping The following table, Figure 4 and Figure 5 show the different habitat types (e.g. coastal, semi-improved grassland, established saltmarsh etc.) and land uses (arable, gardens etc.) from within the River Hun study area.

Habitat Percent of area Priority Habitat Arable 8.07 No Coastal CFPGM 48.68 YES High Productivity CFPGM 3.74 YES Low Productivity CFPGM 4.17 YES Medium Productivity CFPGM 1.75 YES Coastal sand dunes 4.02 YES Coastal sand dunes/Scrub 0.07 YES Coastal sediment 0.39 NO Coniferous plantation 0.65 NO Dune grassland 3.33 YES Gardens 2.04 NO Hedgerows/Field margins 0.70 YES Humid dune slacks 0.03 YES Improved grassland 2.53 NO Lowland mixed deciduous woodland 0.7 YES Established saltmarsh 5.09 YES Pioneer saltmarsh 0.68 YES Scrub 4.34 NO Semi-improved grassland 5.01 YES Semi-improved wet grassland 1.09 YES Urban 0.88 NO Waterbodies 1.96 YES

It can be seen that most of the habitats recorded in the River Hun study area are classified as being priority habitats. These are habitats have been designated under the Natural Environment and Rural Communities Act (2006) Section 41 habitats of principal importance for their species diversity and as those most threatened and requiring conservation. The most dominant habitat type within the River Hun area is coastal CFPGM (Coastal Flood Plain Grazing Marsh: 48.6%). Another notable habitat type found in the River Hun area is the coastal sand dunes (4.02%). This habitat is especially vulnerable due to rising sea levels and increasing levels of coastal erosion.

Small Saline lagoons, North Norfolk Coast© Copyright N Chadwick and licensed for reuse under this Creative Commons Licence.

Figure 4 Unique habitat features Two of the habitat features found within 19% the River Hun study area have been identified as nationally and internationally important. These are the embryonic shifting dunes and saline lagoons. The embryonic shifting dunes, as found within the far northern point of the study area, have been identified in the aforementioned North Norfolk Coast SAC as one of only 2 sites of this habitat in the east of England. The 81% saline lagoons are listed as one of the Priority Habitats internationally important sites on the North Non-Priority Habitats Norfolk Coasts’ Ramsar and SAC citations This chart shows the percentage of the River and is listed as a priority Annex 1 habitat Hun area that has been identified as priority within the Habitats Directive. habitat.

Figure 5

SPECIES

Species records With its varying habitats and geographical location, the River Hun study area is home to a wide variety of both common and scarce species. NBIS holds a total 93,996 records from the study area, comprising of 2471 individual species. This chart shows the number of different species group records from within the River Hun study area. [Based on the data held by Norfolk Biodiversity Information Service, March 2019].

Fungi & Lichen Plants Butterflies Herptiles 277 1968 735 Mammals 86 272 Other Invertebrates 714

Moths 57536

Birds 67227

You can see from the chart that the records held by NBIS for the River Hun study area are dominated by bird and moth records. The Norfolk Ornithologists’ Association hold regular bird ringing and moth trapping events at Holme dunes which explains the high proportion of records from these species groups. Rare species 123 species that have been recorded in the River Hun study area are listed under Section 41 (S41) of the 2006 Natural Environment and Rural Communities (NERC) Act. Section 41 includes a list of habitats and species which are of principal importance for the conservation of biodiversity in England, this is used in decision making by local and regional authorities in order to conserve biodiversity. There are 943 species listed on section 41 meaning that more than 13% of

Eurasian Bittern these protected species have been recorded in the https://www.flickr.com/photos/lincsbirder/ [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)] River Hun study area.

Notable species The ruff NBIS holds 178 records of Ruff (Calidris pugnax) within the River Hun study area. The Ruff is a medium sized migratory member of the sandpiper family that uses marshes and wet meadows for breeding across northern Europe. This species is listed on the North Norfolk Coast Ramsar citation because 19.2% of the UKs breeding population is found there. The bittern The Bittern (Botaurus stellaris) is a species that has suffered massive population declines throughout its range over the past century, and continues to decline in many regions. Due to their unique feeding techniques and tendency to nest at ground level, they are particularly vulnerable to reed bed destruction and predation. 178 bittern records are held by NBIS within the River Hun study area with the first bird being recorded there in 1991. Non-native species Due to the actions of man, including deliberate introductions and escapees, may non-native species can be found living wild in the UK. NBIS holds a total of 466 records of non-native species within the River Hun study area. This chart shows the non-native species groups that have been recorded in the study area. [Based on the data held by NBIS, March 2019].

Mammals Plants 22 14

Birds 430

You can see from the chart above that the majority of the non-native species recorded in the River Hun Study area is made up of bird records (92%). Only 3% of the recorded non-native species were plants, whilst 5% were mammals

Non-native flora Non-native species pose a great risk to unique habitats. Although there are only 14 records of non-native plant species within the River Hun area, 5 of these are for Himalayan balsam and two for New Zealand pigmyweed. Himalayan balsam poses the threat of out competing native species, causing land erosion and has the potential to clog up the fragile waterways within

Himalayan Balsam © Copyright Anne the River Hun area. New Zealand pigmyweed Burgess and licensed for reuse under poses a serious threat of outcompeting native this Creative Commons Licence. aquatic plants. It can tolerate brackish water and is therefore at risk of growing in the internationally protected saline lagoons. Both of these species need intensive control measures and pose the greatest risk to the unique habitats of the area. Non-native fauna There have been 430 records of non-native birds within the River Hun study area, 394 of these consist of just three species: The ruddy duck, the Egyptian goose and the Canada goose. The Egyptian goose and the Canada goose threaten the River Hun environment by causing physical damage to habitats through trampling and extensive grazing. They also pose a threat to the still-water aquatic habitats of the area with their high nutrient droppings causing eutrophication. The ruddy Egyptian Goose © Copyright Mike Quinn and duck poses no threat to the River Hun licensed for reuse under this Creative Commons environments but has been the subject of Licence. ongoing control measures due to the threat it poses to Spanish population of the internationally endangered white-headed ducks. This species has not been recorded in the River Hun area since 2013. There have been 2 non-native mammals recorded in the River Hun area, the Chinese water deer and the Indian muntjac. Neither of these deer have been recorded in high numbers in the area but if they do reach these proportions, they may threaten the lowland deciduous woodland through over grazing of young shoots and damaging mature trees by stripping bark.