TheKent’s State of Wildlife in 2011
Kent Biodiversity Partnership Action for Kent’s wildlife
Contents
Introduction 1
Kent’s Butterflies Mike Easterbrook Butterfly Conservation -Kent 2
Kent’s Moths Ian Ferguson & David Gardner Butterfly Conservation -Kent 5
Kent’s Amphibians and Reptiles Dr Lee Brady Kent Reptile and Amphibian Group 10
Kent’s Birds Andrew Henderson Kent Ornithological Society 18
Kent’s Bats Shirley Thompson Kent Bat Group 26
Kent’s Wild Plants Richard Moyse Kent Wildlife Trust 33
Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust 39
The State of Kent’s Wildlife in 2011
Kent is one the UK’s most wildlife-rich bird species, and two species of bat all counties, a result of its varied geology, became extinct in the county. This long coastline, landscape history, excludes consideration of groups not southerly location and proximity to covered in the following chapters; for mainland Europe. Its important wildlife example, the Red Squirrel and 3 species habitats include estuaries, chalk cliffs, of bumblebee were also lost during the woodlands, and chalk downland, and 20th century. In addition to this, many of encompass some of the South East’s the species that remain have seen big most iconic landscapes, such as the population declines, including many shingle headland of Dungeness and species of butterflies and moths, birds the White Cliffs of Dover. and wildflowers of farmland, wetland plants, Adders and Common Toads. This publication has been prepared by Kent natural historians to give an As seen in the following chapters, the outline of the changing fortunes of causes of these losses and declines are Kent’s wild plants and animals over the various. However, amongst the most last century. It is intended to provide a important are: context for, and to inform, on-going action to protect and restore the • direct loss of land of value to wildlife to county’s wildlife and wild places. built development or intensive farming, which has reduced and fragmented The picture painted here is far from populations of wild plants and animals entirely rosy but is not all doom-and- • intensification of the way land is farmed, gloom. It is recognised, for example, that particularly the use of pesticides and protection of the best wild places, such as artificial fertilisers, which has resulted in nature reserves or Sites of Special losses of wildlife across the wider Scientific Interest, has been successful in landscape, and has increased nutrient protecting some otherwise very levels on land and in water threatened habitats. • changes in the management of woodland, resulting in loss of open It is also the case that a number of space in woods and forests previously rare and threatened species are • climate change, which increasingly recovering. The recent return to Kent of shapes which species are, and are not, birds, such as the Hobby, Buzzard and able to live successfully in Kent Raven, show how conservation measures (in these cases, protective legislation and It has been acknowledged that the UK the banning of dangerous pesticides) can and the other signatories to the 1994 be very effective. Convention on Biodiversity failed to meet their self-imposed target of halting the loss Nonetheless, it is clearly the case that the of biodiversity by 2010. If we still want to last century has seen major losses in achieve this laudable and important aim, Kent’s wildlife. During this period, 30 there is much to do. The information in the species of wild plant, eight species of following chapters will prove invaluable in butterfly, one amphibian, one reptile, 10 guiding future efforts.
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Photo: R I Moyse
Kent’s Butterflies Mike Easterbrook, Butterfly Conservation - Kent
Kent lost eight species of butterfly Folkestone, with occasional sightings from during the last 100 years, and at least two other sites. The Duke of Burgundy three further species now only survive is now confined to a few small colonies in as very localised populations. Habitat one small area of Kent. The Small Blue is change and loss, particularly loss of another butterfly that lives in small downland and wetland, and changes in colonies, with little mobility. Over the last woodland management, are likely to be century many of these colonies have been The Duke of Burgundy the most important causes of butterfly lost to changes in land use and building is now only found population decline. development, so its distribution is now around the Denge very restricted. Its stronghold is on the cliff Wood area However, some butterflies species are tops in the Dover and Deal area, with a showing population increases, or colony in Thanet, two small colonies in recovery from previous declines. mid-Kent and one in north¬west Kent. It is Targeted conservation work is also unlikely to colonise any other areas proving effective. without human intervention and is dependent on the presence of its food The restoration and reconnection of plant, kidney vetch, in suitable condition. existing areas of butterfly habitat is These factors mean that its future is likely to be necessary to maintain and uncertain. The Heath Fritillary is also restore populations in the future. restricted to a small number of sites, but in this case the prospects are more Kent’s butterfly fauna optimistic. This is partly because intensive Some seventy species of butterfly have scientific research has revealed the been recorded in Kent, though a number management requirements that allow it to of these are scarce migrants or flourish and, very importantly, the woods specimens of doubtful origin (i.e. either where it survives are now owned and escapes or deliberate releases from managed by conservation organisations. captivity). There are now forty species which are resident in the county, as well Apart from the species mentioned above, as one regular migrant which may there are other butterflies that have occasionally breed here (the Clouded suffered declines in range, but less Yellow) and a number of irregular catastrophically. These include three migrants, such as the Swallowtail. species of Skipper butterfly, the Dingy, Grizzled and Silver-spotted, and the Dark Green Fritillary. In many cases colonies of Species known to have been resident these butterflies have been lost because in Kent and now extinct, with dates of changes in habitat, particularly the loss when last seen of huge areas of chalk downland to arable
farming or to scrub. Photo: R I Moyse Glanville Fritillary Pre-1900 Wood White 1915 Nationally, more than two-thirds of our Black-veined White 1920s resident butterfly species have become Marsh Fritillary 1945 less widespread since the 1970s, and Brown Hairstreak Early 1970s 54% of the species assessed by Butterfly High Brown Fritillary Early 1970s Conservation have declined in overall Silver-studded Blue 1970s population size in this time. In some Small Pearl-bordered cases, these declines have been Fritillary 1991 substantial: populations of the Duke of Pearl-bordered Fritillary 2002 Burgundy and
Several species are just about hanging on Heath Fritillary (both of which have The Dingy Skipper has in Kent at the moment. The Grayling is in a important colonies in Kent) declined by undergone declines particularly precarious position, as it is 58% and 46% respectively in the period and is now on the UK now reduced to one main colony near 1995-2004. Biodiversity Action Plan priority list
3 Photo: Bryony Chapman
Kent’s Butterflies Mike Easterbrook, Butterfly Conservation - Kent
Positive change in butterfly populations Conclusions There have been many changes in the It is not all bad news, however. Some populations of butterfly species in Kent butterflies are more numerous now than at over the last hundred years and many of various stages in the last 100 years. Some these changes cannot be attributed to of them have experienced major changes habitat loss. However, for the less mobile in numbers and distribution over that species that live in discrete colonies, loss The Silver-washed period. The Comma, now a fairly common of habitat is a major factor in their decline. Fritillary was previously butterfly in gardens, woods, and the wider Changes of land use also have major veryrare in Kent, but countryside, was extremely rare in Kent for implications for recovery of butterfly has recently expanded a century or more prior to 1930. Another populations – when suitable habitat is its range butterfly that is common now, the greatly reduced and fragmented it is Speckled Wood, was absent from Kent difficult for butterflies to find and re- from 1913 to 1942, before returning to colonise. Isolated nature reserves are often west Kent in the 1940s and spreading to unlikely to be re-colonised without difficult much of the county by 1960. The and costly artificial releases and will be Gatekeeper and Essex Skipper are two vulnerable to subtle changes in habitat more butterflies that increased their range caused by changes in management and in the 20th century and are common climate. today. As increasing amounts of land are lost to Two woodland butterflies, White Admiral building development and large areas of and Silver-washed Fritillary, both became farmland are unsuitable for supporting very scarce in Kent between 1960 and butterfly populations, it is vital that other 1980. The White Admiral was the first to land is protected or restored. It is also recover, re-colonising from the west during essential that suitable areas are linked the 1990s. The rate of spread has together, so that butterflies and other probably increased over the last few years, wildlife can spread between them. and it is now recorded again in east Kent. 2006 saw the most records for Silver- washed Fritillary in Kent for many years and this upward trend has continued, with References reports from more new sites in 2010. Butterfly Conservation, Kent Branch. Annual Reports, 1994-2006. Chalmers- A number of butterflies are also benefiting Hunt, JM. (1961). The butterflies and from targeted conservation action: moths of Kent.
• the reintroduction of woodland Chalmers-Hunt, M. (1979). Supplement to management to the Blean Woods the butterflies and moths of Kent. Embry, complex led to major increases in what is B & Youden, GH. (1949). The butterflies now the UK’s most important population and moths found in the Dover and Deal of Heath Fritillary district of Kent. • projects to reintroduce the Adonis Blue and Silver-spotted Skipper to Kent Folkestone Natural History Society (1968). Wildlife Trust reserves at Queendown Some aspects of the natural history of the Warren and Burham Down have been Folkestone District. Fox, R et al. (2006). highly successful, with the Adonis Blue The state of butterflies in Britain and subsequently colonising other sites Ireland. nearby. • a project by Butterfly Conservation is re- Philp, EG. (1993). The butterflies of Kent. establishing woodland management for Kent Field Club Scott, E. (1936). A list of the Duke of Burgundy at a number of the butterflies and moths occurring in the sites in and around Denge Woods near neighbourhood of Ashford, Kent. Canterbury
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Ian Ferguson and David Gardner, Butterfly Kent’s Moths Conservation - Kent
Kent’s moth fauna has undergone informed assessment shows that, over the substantial change over the last 100 20th century, the county lost thirty-seven years, with species being lost and species and gained nineteen species. gained, often naturally, but also due to human activity. Some new arrivals probably simply reflect this continual flux, although other changes However, the number of species lost may reflect a range of factors. For far outweighs the number gained, and example: must also be seen against national declines in moth populations. • pine Hawk-moth was previously Habitat loss and the massive increase recorded as a migrant, but has moved in pesticide use during the 20th into Kent from the west, perhaps as a Century are likely to have had major result of climate change impacts on moth populations. • clay Triple-lines, which used to be found by searching under beech hangers now Introduction seems to use beech hedges, so can be Some 2000 species of moth (out of a found almost anywhere in Kent. Other national total of around 2,500 species) species whose expansion reflects have been recorded in Kent, though some changes in parks and gardens include of these are one-offs, some very hard to Blair’s Shoulder-knot, which mainly find, and others no longer believed to be feeds on non-native cypress trees. here. Species range in size from tiny leaf- mining moths to the Death’s-Head Hawk- Change in the number of moth species moth: nearly 750 species of larger moth recorded in Kent have been found in the county, representing over 80% of the UK fauna. Period Gain Losses Kent has important populations of a 19th c Unknown 10 number of rare moth species, including Straw Belle on the Kent Downs, and the 20th c 19 37 coastal species Bright Wave and Fiery 21st c 6 4 Clearwing, the latter being now entirely restricted to Kent. • species such as Orange Footman, which feed on lichens, have increased Kent is an important county for moths as following reductions in air pollution in the it is very close to the continent, so second half of the 20th Century, and the migrant species can reach this country associated increase in pollution-sensitive and attempt to breed. Kent receives lichens. regular influxes of common species, and in years with poor migrant numbers the In the UK as a whole, 62 moth species count of moths in garden moth-traps is became extinct during the 20th century. seen to be lower. The regular movements However, species extinctions are only part of migrants keep the UK populations in of the picture, and the key concern is the touch genetically with the main centres of recent massive decline in the numbers of the species in mainland Europe. many moth species. Of the 337 larger moths species for which a UK population- Change in moth populations trend has been generated, two-thirds There is constant change in the number of show declining populations, and seventy- moth species living in Britain, as resident one species – a fifth of the total – have species are lost and new species declined in numbers by more than 70% colonise. over the last 35 years. Population declines have been particularly severe in the South This pattern is reflected in Kent; an East.
6 Photo: David Green, Butterfly Conservation Ian Ferguson and David Gardner, Butterfly Kent’s Moths Conservation - Kent
Kent has not been immune from these Habitat change and loss changes. For example: Habitat loss accelerated in the second half of the 20th Century with increased • the V-Moth, which has shown a 97% built development and intensification of national decline since 1968, was last agriculture and forestry. Nationally, it is seen in Kent in 2003. estimated that 80% of chalk grassland, • the Garden Tiger- so named because it 97% of lowland hay meadows, 40% of was once seen commonly in gardens– lowland heathland, and 67% of Heart moth. This has declined by 89% nationally, and in hedgerows were lost over this period species ceased to Kent is now almost entirely restricted to (though substantial lengths of new breed in Kent during the 1990s the coast. hedgerow have been replanted since • the Barred Umber has declined to a 1990). Figures for Kent are harder to point where we have no record since determine, though heathland in the 2005 county has probably declined by two- • the Lace Border has declined and thirds since the mid-1940s. disappeared from many locations, now restricted to a few downs in Surrey and Agricultural and forestry intensification Kent. did not just lead to direct habitat loss (for • black-veined Moth has declined and is example, by ploughing and reseeding of now restricted to the eastern downs of grasslands, draining of wetland and Kent. grubbing of woodland), but resulted in the abandonment of marginally Causes of change in moth populations productive agricultural land, such as There are likely to be a number of chalk grassland and heath, and to a reasons why moth populations have sharp decline in traditional, commercial declined so massively over recent management of broad-leaved woodland. decades. Among the most important in The resulting changes to habitats Kent are likely to be habitat loss and resulted in loss of populations as shading fragmentation, changes in habitat by trees and scrub led to lower ground management, increased use of temperatures and loss of foodplants. As pesticides and climate change. Light an example, the loss of chalk grassland pollution may also be an important issue to scrub following the introduction of for moths, though its impact is hard to myxomatosis in the 1950s was the likely separate from other effects of cause of the extinction of the Feather Ear urbanisation. in Kent (last recorded in 1963).
7 Ian Ferguson and David Gardner, Butterfly Kent’s Moths Conservation - Kent
LOSSES GAINS Year Species Year Species
1831 Bordered Grey 1903 White-barred Clearwing 1865 Grey Scalloped Bar 1924 White-banded Carpet 1868 Kentish Glory 1927 Sallow Clearwing 1873 Frosted Yellow 1935 Vine’s Rustic 1876 Scarce Dagger (1) 1948 Reed Dagger 1881 Brighton Wainscott 1953 Marsh Mallow Moth 1891 Purple-bordered Gold 1965 Cypress Pug 1891 Dusky Clearwing 1965 Silver Barred 1895 Scarce Black Arches (1) 1968 Blair’s Shoulder-knot 1899 Gypsy Moth (1) 1975 Sloe Pug 1902 Scarce Burnished Brass 1981 Feathered Beauty 1903 Spotted Sulphur 1984 Dusky Peacock 1909 Dingy Mocha 1990 Sandhill Rustic 1909 Small Ranunculus (2) 1992 Large Ear 1916 Marbled Pug 1993 Radford’s Flame Shoulder 1916 White-marked (1) 1995 Balsam Carpet (4) 1948 Dark Crimson Underwing 1995 Tree-lichen Beauty 1951 Small Eggar 1997 Small Ranunculus (2) 1955 Cistus Forester 1997 Dotted Chestnut 1955 Beech-green Carpet 1999 Cypress Carpet 1955 Butterbur 2000 Fisher’s Estuarine Moth (5) 1956 Dark Brocade 2001 Jersey Tiger 1956 Bond’s Wainscott 2002 Clancy’s Rustic 1958 Narrow-bordered Bee Hawk-moth 2003 Langmaid’s Yellow Underwing 1958 Lunar Double-stripe 2003 Splendid Brocade 1959 Orange Upperwing 2004 Porter’s Rustic 1960 Dentated Pug 2010 Raspberry Clearwing 1961 Double Line 1963 Feathered Ear 1963 White-barred Clearwing (2) 1965 Grass Wave 1967 Four-spotted (3) 1968 Argent & Sable 1968 Cudweed 1968 Light Crimson Underwing 1973 Horse Chestnut 1974 Autumn Green Carpet 1975 Sloe Carpet 1976 False Mocha (1) 1976 Wood Tiger 1976 Small Black Arches 1977 Lesser Belle 1984 White-spotted Pinion 1987 Five-spot Burnet NOTES 1988 Essex Emerald 1992 Pale Shining Brown (1) (1) Still occurs as a migrant 1994 Heart Moth (2) Recolonisation following earlier loss 1999 Scarce Forester (3) May have recolonised subsequently 2000 Scarlet Tiger (4) Presumed date; first confirmed 2005 2001 Bordered Gothic (5) Introduced 2003 V-moth
8 Ian Ferguson and David Gardner, Butterfly Kent’s Moths Conservation - Kent
Pesticide use southern distribution are showing The use of garden and agricultural expansions in range in the UK. How pesticides increased substantially during climate change is involved in moth decline the second half of the 20th century, is less clear, though studies on the although the use of agricultural Garden Tiger moth have shown that it insecticides has declined over the last 20 declines after wet winters and warm years (in the South East, the total weight springs. of insecticides are applied declined by nearly 70% between 1990 and 2006). Agricultural herbicide use in the South Easthas also declined over the last 20 years (though in this case by only about References 25%), though the area treated (the area Butterfly Conservation, Kent Branch. over which insecticides applied multiplied (2003). An Initial Checklist of Kent by the number of treatments), has Lepidoptera. increased. Butterfly Conservation has suggested that the effectiveness of Butterfly Conservation. (2006).The State herbicides in reducing weed populations of Britain’s Larger Moths. may be impacting on moths by reducing the availability of food plants. Food and Environment Research Agency website (http://pusstats.csl.gov.uk). Climate change The effects of climate change on moths Kent Biodiversity Action Plan website are likely to be mixed. Some species with (www.kentbap.org.uk). Photo: Mark Parsons, Butterfly Conservation
Jersey Tiger. A new species to Kent in 2001
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Dr Lee Brady, Kent Reptile Kent’s Amphibians and Reptiles and Amphibian Group
During the 20th century, Kent lost one of have revealed that amphibian populations its five reptile species, and one of its six can experience cycles, with numbers amphibians. National declines in increasing over several years followed by populations have been so severe that all declines before the cycle repeats itself. Kent’s reptiles, and three of its seven amphibians are listed as Priority species Common Frogs are distributed across the in the UK Biodiversity Action Plan. county and frequently recorded in urban and suburban areas, particularly where Habitat loss and fragmentation are the there are large numbers of small garden most important factors causing declines ponds. In the wider countryside, Common in amphibian and reptile populations. Frog pond occupancy appears to be Built development is very significant as negatively influenced by high pond density, ‘brownfield’ sites can hold large reptile because high pond density is associated populations, and all species have trouble with high populations of Great Crested crossing artificial barriers such as large Newts, which feed on frog tadpoles. In such roads. areas, Common Frogs often breed in relatively small ponds that desiccate too Europe has around 60 amphibian species early in the season to support large and around 120 reptile species. However, numbers of aquatic predators. just seven amphibian species (including the reintroduced Pool Frog) and six native Common Toads tend to breed in larger, terrestrial reptiles were able to colonise the more permanent waterbodies that British Isles before they became isolated frequently support populations of fish, as from the rest of Europe. Kent has even toxins present in the skin of toad tadpoles fewer species with native populations of Pool Frog and Smooth Snake never Smooth and Palmate Newts display very recorded. Although Kent populations of similar life histories and frequently occupy Natterjack Toad and Sand Lizard became the same breeding ponds. However, extinct in the 1960s, both species are now Palmate Newts have never been recorded subject to reintroduction projects. In from some areas of Kent (e.g. Sheppey, addition, several new species have been Thanet and Dungeness), even though these introduced and now form viable breeding areas do support populations of Smooth populations. Newt. Analysis of habitat data reveals that areas not occupied by Palmate Newt Current Status of Herpetofauna typically display relatively low tree cover and The secretive and cryptic nature of Kent’s historically were probably never heavily herpetofauna means that they are not wooded. This is probably related to Palmate always easily visible. This can create Newts’ greater tolerance of acidic difficulties in establishing species presence conditions, which may give them a and determining population status. competitive advantage in Kent’s woodland ponds. Native Amphibians The most important factor limiting This makes them relatively unpalatable to amphibian populations is the number of predatory fish. The number of larger more available breeding ponds. Outside of the permanent ponds and lakes in Kent is lower breeding season, amphibians can disperse than that of smaller more ephemeral in terrestrial habitat (for some species waterbodies, and this limits the potential dispersal can even occur over several distribution of Common Toad. Survey work kilometres when habitat connectivity is in Kent also suggests that the largest toad high). Detectability of animals in terrestrial populations are more frequently found habitat, and sometimes even in ponds, can where there are no significant dispersal be very low, but long-term population barriers between breeding sites and good assessments that control for detectability quality terrestrial habitat (e.g. woodland).
11 Dr Lee Brady, Kent Reptile Kent’s Amphibians and Reptiles and Amphibian Group
National declines in Common Toad have Non-Native Amphibians resulted in the species’ designation as a Twelve Hungarian Marsh Frogs were Biodiversity Action Plan Priority Species. introduced to a garden at Stone-in-Oxney in 1936. From this, and other introductions The most important factor influencing the (including on the Isle of Sheppey and the Kent distribution of Great Crested Newt is Hoo Peninsula), the species has significantly rural pond density. Kent has exceptionally expanded its range. Populations have high pond density, with some areas of the established across Romney and Walland Low Weald displaying more than 50 ponds Marshes as well as along the Medway and per km2. Pond densities lower than 4 ponds Stour river valleys, with large numbers of per km2 are limiting for Great Crested Newt, Marsh Frogs now regularly seen at Sandwich but as pond density increases above this and across the North Kent Marshes. In the value, occupancy by Great Crested Newt Kent Weald, Marsh Frogs have spread as far also increases. In areas of high pond density, west as Horsmonden. Marsh Frog is very Great Crested Newt may even be found in similar to the Pool and Edible Frogs (the relatively poor quality ponds. Such ponds latter a hybrid of the other two species). All may not necessarily be used for breeding three species have been introduced to Kent, and any breeding that does take place may and reports of very loud calling frogs could not be successful. Of the 17,000+ ponds be attributed to any of the three species. believed to occur in Kent, 44% have been estimated as occupied by Great Crested At least three areas in Kent are believed to Newt whilst 32% may be used for breeding. support breeding Alpine Newt. In the 1990s,
The relationship between Great Crested Newt pond quality and pond occupancy. The horizontal axis shows predicted pond quality derived from habitat suitability indices. Note that Great Crested Newts can sometimes occur in poor quality ponds and do not always occupy excellent quality ponds
12 Photo: Lee Brady Dr Lee Brady, Kent Reptile Kent’s Amphibians and Reptiles and Amphibian Group
Alpine Newts were introduced to two considered to be more tolerant of waterbodies located at different disturbance and increased predation risk Canterbury sites. Successful breeding at from cats. Spending much of their time both sites has resulted in colonisation of underground, Slow-worms prefer habitats other nearby ponds and the population that display previously disturbed ground expansion is considered likely to (e.g. gardens and old allotments) and continue. appear to be less frequently encountered American Bullfrog is a large amphibian in areas that are subject to regular Viviparous lizard species that used to be sold in some pet flooding (e.g. Romney Marsh). Viviparous shops and garden centres (as large Lizard and Slow-worm are positively tadpoles). Following several years of associated with areas of woodland. infrequent reports of bullfrogs from ‘Brownfield sites’, which often have multiple localities, a breeding population structurally complex vegetation and lots became established in West Kent. This of opportunities for shelter and basking population was subject to an eradication (e.g. brick and concrete rubble, wooden programme organised by Natural posts, areas of open ground, etc.) are England. Follow-up survey work is being often occupied by these species, and undertaken to determine whether satellite population estimates at such sites have populations have established in nearby revealed densities of over 500 Viviparous waterbodies. Lizards per hectare and over 2,000 Slow- worms per hectare. Native Reptiles Reptiles are secretive and cryptic, and Population levels within the wider can therefore be difficult to survey. countryside are generally considered to However, all of the widespread species be lower, though populations can are considered to be experiencing become very high if an appropriately national declines and have recently been complex vegetation structure is provided. elevated to BAP Priority Species status. Where grazing results in short and even grassland, populations may decline Viviparous Lizard and Slow-worm display rapidly. In such situations, Viviparous broadly similar habitat requirements and Lizards may appear to become ‘edge are often recorded from the same sites. species’, occupying areas of rough However, unlike Viviparous Lizard, Slow- vegetation along field boundaries or worm is frequently recorded from urban interface habitat between grassland and and suburban gardens where they are scrub or woodland.
Google Earth map illustrating projected range of adder derived from statistical analysis (nearest neighbour) of individual records. Darker areas represent locations where there is a higher probability of encountering the species.
13 Dr Lee Brady, Kent Reptile Kent’s Amphibians and Reptiles and Amphibian Group
There are concerns over national declines manure heaps and compost bins, are in Adder populations, and declines have often used in successive years, with been reported from several well-studied incubation rates dependent upon climatic Kent sites. In Kent, Adder is highly conditions. Grass Snakes are highly localised with populations centred on mobile and individuals can range over areas of high quality habitat. Typically such several hectares or even kilometres to find areas are located in or close to woodland suitable nesting sites, and the need to lay and/or scrub, with many of Kent’s Adder eggs may act as a constraint on their populations found in areas of more distribution. Radio-tracking studies have structurally complex chalk grassland and shown Grass Snakes to disperse over scrub along the North Downs. Adder several kilometres whilst occupying a wide populations are composed of fewer range of different habitats, with some individuals than lizards, with counts of just individuals even spending significant 30 to 50 animals per hectare considered amounts of time within arable crops. normal. Low population densities, and the Increased populations of amphibian fact that female Adders do not reproduce species such as Marsh Frog, are likely to every year, mean that populations are have resulted in local population slow to respond to improving habitat increases; studies at Fordwich have conditions. Adders are also slow to revealed that Marsh Frog now forms an colonise surrounding sites. Juvenile important dietary component for snakes Adders feed on Viviparous Lizards, and at this location. declines in lizard population can result in several years of low Adder recruitment. Sand Lizard is another egg-laying reptile species and appears to require a sandy Fortunately, Adders are relatively long substratum for egg deposition. In Britain, lived; wild individuals have been recorded the species is at the edge of its European surviving to 30 or more years. However, range and is restricted to sand dune and this does mean that non-breeding adult lowland heathland habitats. In Kent, just animals may still be recorded from a site six historical records exist for Sand Lizard, for several years after the population has and the species is believed to have ceased to be viable; survey work must become extinct in the 1960s. Recently, a therefore establish the population project has been undertaken to introduce structure to determine long-term viability. Sand Lizard to a dune system in East Analysis of available habitat data has Kent. Although there have been some revealed that of the 4,456 kilometre early successes and neonate lizards have squares in Vice Counties East and West successfully survived their first winter, the Kent, 25% are probably of above average long-term viability of the population has suitability for Adders. However, Adders yet to be determined. have been recorded from only 10% (109) of these squares. Low dispersal rates and Non-Native Reptiles unsympathetic site management are Reports of unusual lizards have been believed to be important reasons for this received for several years at sites close to low figure. Folkestone. The first such report was submitted by Dr. Phil Shore in 1996, he Grass Snake is probably the most widely reported that Wall Lizards were believed to distributed reptile species in Kent. have been deliberately released by a local Although they are more likely to be pet shop that was unable to sell them. In encountered close to freshwater, Grass 2007, Julian Russell submitted the first Snakes have also been recorded away confirmed record for the species. Recent from water in woodland areas on the observations of Wall Lizard at two nearby North Downs, and adult females my well locations suggest that the population may use rotting timber within the woodland for be expanding its range. egg laying. Egg-laying sites, such as
14 Photo: Lee Brady Dr Lee Brady, Kent Reptile Kent’s Amphibians and Reptiles and Amphibian Group
A small number of Green Lizards were long-term population trends at receptor introduced to a site near Sittingbourne in sites. Increasing development pressure 1962. The population is not believed to will continue to impact on available habitat have bred successfully and soon died out. and also lead to increased habitat There is also an account of Green Lizards fragmentation. being recorded at Herne Bay in M.C. Cooke's Our Reptiles and Batracians Habitat Fragmentation (1893). No further records have been Amphibians and reptiles display poor Female adder received from this site. dispersal capabilities. Colonisation of new habitat occurs relatively slowly and sites Records of the North American Red-eared that are isolated by significant dispersal Terrapin are sometimes received from barriers (e.g. major roads, large arable ponds in urban parks and other sites fields or other expanses of unfavourable frequented by the public. Individual habitat) may never be colonised by some terrapins are long-lived and animals can species. Despite the large number of small be encountered at the same site over garden ponds that occur in urban areas, several years. There are no confirmed an analysis of available data reveals that records of terrapins breeding in Kent. the habitat that most negatively influences Great Crested Newt pond occupancy is Future Trends ‘built up’; the species is largely absent Habitat Loss from urban areas where dispersal Direct loss of habitat through changes in between ponds is significantly land-use is the most important factor constrained. influencing the current status of Kent’s reptiles and amphibians. Although Kent Survey work in Kent and other counties still includes a very large number of has revealed Adder to be a species that is ponds, many waterbodies have been lost also highly sensitive to habitat over the past 100 years. Ponds have been fragmentation. Such fragmentation can filled, lost to succession or subject to lead to inbreeding depression (reduced reduced water quality through agricultural fitness caused by breeding of related run-off. In towns and rural gardens, ponds individuals). If future herpetofauna are frequently managed as amenity conservation in Kent cannot be achieved features. Such ponds may be deepened at the landscape level through significant and fish introduced. All of these factors reduction in fragmentation, the status of can limit amphibian breeding success. small isolated populations of species such as Adder are likely to decline. Kent is a county that is subject to increasing pressure from development. Unsympathetic Management Current government policy is to target Herpetofauna populations can be lost previously developed sites. Brownfield simply because their presence was not sites, which are a primary target for known or taken into consideration when development, often support good land management decisions were being populations of Viviparous Lizard and planned. This situation is exacerbated Slow-worm. Pre-development work because dispersal barriers increasingly frequently includes the capture and isolate populations. For example, one translocation of many hundreds of well-studied site close to Maidstone was individual animals to receptor sites. Work found to be devoid of Viviparous Lizard undertaken by ecological consultants has despite historical records in known revealed that such projects can succeed populations within nearby areas. Despite in establishing new populations, at least in of its relatively large size, the Maidstone the short term. However, translocation site is isolated by major roads. Lizard projects are often poorly monitored and populations are believed to have insufficient data is available to determine disappeared due to previous
15 Dr Lee Brady, Kent Reptile Kent’s Amphibians and Reptiles and Amphibian Group
unsympathetic management: recent development pressure, leading to an changes in the management regime increasing human population. Pressure on resulted in a significant improvement to herpetofauna habitats will continue to reptile habitat, but colonisation was increase in future years, with direct constrained by surrounding dispersal persecution of animals at sites regularly barriers. Artificial introduction of lizards visited by the public already evident. was followed by four years of monitoring Fortunately, some human activities can that have confirmed continued breeding actually benefit herpetofauna. For success. This suggests that reversing example, sympathetic management of unsympathetic management; practices ponds and lakes for fishing benefits may not result in the immediate natural Common Toad, whilst increasing interest recolonisation of sites. in composting provides opportunities for Slow-worm and Grass Snake. Targeted management of readily identifiable habitat features such as Non-native Species and Disease amphibian breeding ponds is regularly The potential future impact of introduced undertaken by land managers. However, amphibians on native species is not other important habitat features may be currently known. However, Marsh Frog, less obvious. For example, several Alpine Newt and American Bullfrog are individual Adders may use the same known carriers of chytridiomycosis, an subterranean shelter during the winter. infectious disease of amphibians that is Such hibernacula are critically important believed to be responsible for amphibian for populations, yet their specific locations population declines in several other may not be known to land managers. countries. Field samples have confirmed Unsympathetic management of habitat that some Kent populations are also around hibernacula can result in increased infected, although negative impacts on shading (e.g. tree planting in forestry local status have not yet been observed. plantations), while excessive vegetation clearance can increase the detectability of Marsh Frog and American Bullfrog can eat Adders to predators during the spring native amphibian species and have the ‘lying out’ period. potential to reduce local populations. In the Low Weald, large fishponds which Lizard and Adder populations are might offer a refuge for Common Frogs dependent upon prey species that favour (because they are unlikely to support structurally complex vegetation swards breeding populations of Great Crested (i.e. invertebrates and small mammals). Newt) are rapidly being colonised by Striking a management balance for Marsh Frog. Much more survey work is species that frequently occupy such required to determine the interaction habitats is certainly challenging, but better between fish, newts and frogs, and the assessments of the needs of implications for the future distribution of herpetofauna and their likely presence Common Frog. must be achieved if populations are not to decline, including land managed for nature The impact of fish on amphibian conservation. populations is widely recognised. However, recent survey work has Public Pressure and Persecution indicated that populations of the Significant attempts have been made in introduced North American Signal Crayfish recent years to increase herpetofauna may also negatively impact populations. awareness amongst conservation At some locations incidents of red leg frog practitioners and the general public. This mortality have been reported. Analysis of has resulted in a great deal of success, specimens from several sites has and the needs of different species are now implicated ranavirus and the disease is much better understood. Yet Kent is a thought to be more prevalent in stressed county that is experiencing significant populations.
16 Dr Lee Brady, Kent Reptile Kent’s Amphibians and Reptiles and Amphibian Group
Climate Change References Although the fact that climate change will Beebee, T & Griffiths, R. (2000). affect Kent species is widely accepted, Amphibians and Reptiles. Collins. specific impacts are poorly understood. One study has suggested that climate Davis, GAN & Frazer, JFD. (1990). The change will result in changes to Kent’s distributions of newts in Kent. hydrology, resulting in earlier pond Transactions of the Kent Field Club, 11 desiccation. Loss of breeding ponds will (2), 661-68. negatively impact on species such as Great Crested Newt, with populations Edgar, P, Foster, J & Baker, J. (2010). increasingly confined to areas of highest Reptile Habitat Management Handbook. pond density. Other species may potentially benefit from this change, such Gent, AH & Gibson, SD. (1998). as Common Frog, which is believed to be Herpetofauna Workers’ Manual. Joint constrained by Great Crested Newt Nature Conservation Committee, predation. Future impacts of climate Peterborough, change on reptiles are even less certain. Hot dry periods result in reduced Inns, H. (2009). Britain’s Reptiles and encounter rates for many reptile species Amphibians. WildGuides. as animals become less active. Slow- worm reproduction appears to occur Jehle, R, Thiesmeier, B & Foster, J. (2011). much later in years with low precipitation, The Crested Newt. Laurenti Verlag and possibly due to summer shortages of British Herpetological Society. mollusc prey. If climate change increases the likelihood of hot dry summers, it could Lagton, T, Beckett, C & Foster, J. (2001). result in population declines. Great Crested Newt Conservation Handbook. Froglife. Conclusions The current status of Kent’s herpetofauna Philp, EG. (1998). Provisional atlas of the is directly related to past human activity. amphibians and reptiles of Kent. Intensive agriculture and development Transactions of the Kent Field Club, 15 (2), have led to habitat loss and 61-82. fragmentation, resulting in the extinction of two Kent species. Some species have also been directly targeted through persecution. Yet there have also been positive benefits. Widespread historical pond creation in the Low Weald has benefited amphibians such as the Great Crested Newt, whilst the introduction of non-native Marsh Frogs has increased the available prey for Grass Snake. Today’s increased awareness of herpetofauna in terms of both distribution and habitat requirements provides a solid foundation for future conservation efforts.
17
Kent’s Birds Andrew Henderson, Kent Ornithological Society
The fortunes of Kent’s birds have • 1909 -N. F. Ticehurst’s History of the fluctuated over the 100 years for which Birds of Kent good records are available. Some • 1953 -J. M. Harrison’s The Birds of Kent species have increased in population, • 1976 -The final year covered by D. W. while others have decreased. Taylor, D. L. Davenport & J. J. M. Flegg’s 1981 The Birds of Kent Twenty-five species started breeding • 2010 -Current assessments and draft regularly in Kent only in the last 100 texts for the prospective new Birds of years. Some escaped from captivity, Kent others took advantage of new, man- made habitats, while a number were In addition, we have taken into account responding to climate change. current trends, where they differ from those pertaining over the previous 30 Ten species no longer breed in the years. county, with habitat change – especially changes in farming practices Birds are perhaps better recorded than – being the major cause. any other group of animals or plants. This is not only helpful to any account of the Conservation work has been effective changes of birds’ status but also for a number of species, particularly something of a problem, since there is a protective legislation which prevents large amount of information and we have, persecution of birds of prey, and for example, to disentangle differing habitat creation for wetland birds. trends between resident and migratory However, more and more species are populations of the same species. We have showing declining populations tried to make allowances for the changing numbers, skills and focus of observers but Around 420 or so species have been it is often difficult to be sure exactly what recorded in the county, although many of the earlier accounts really mean. Deciding these are scarce or rare migrants on what the trend has been for any one occurring in small numbers. We have species is often a matter of judgement. used a range of sources to examine the trends of all breeding, passage and Bird trends through the past century wintering birds, and especially the 215 The table below shows the numbers of regularly occurring species. species judged to be increasing, decreasing, or showing little change Since 1900, there have been three major during the periods between each of our publications describing the status of birds time points, and currently. Totals are in Kent, in 1909, 1953 and 1981. These shown separately for all species on the have been our key sources for the majority Kent list, for those of regular occurrence, of the period under review. The Kent and those breeding here regularly at some Ornithological Society was formed, and point during 1900 - 2010. We have also started publishing annual reports, in 1952; attempted to decide whether species these together with the wealth of other have increased or decreased significantly information – from individual species’ over the whole period 1900-2010, studies, the Breeding Bird Survey, The ignoring such ups and downs. Wetland Bird Survey, and many others – have been used as the basis for However, it should be noted that it is not assessments of trends in the more recent always the same species which show a period. The four time points at which we decline (or increase) in each time period. have described the status of each species For many species, trends have changed are as follows: over the years, an example being the
19 Photo: Andy Vidler
Kent’s Birds Andrew Henderson, Kent Ornithological Society decline of many birds of prey as a result of captivity. The appearance of four other the use of persistent organochlorine gained species is mainly climate-related, pesticides and their subsequent recovery though with significant habitat influences following the chemicals’ withdrawal. Thus, in some cases: Little Egret, Mediterranean Sparrowhawk was fairly common early in Gull, Cetti’s Warbler and Savi’s Warbler the 20th century as it is now, but did not (the last only just classable as regular). nest in Kent for much of the 1960s. Little Ringed Plover colonised Britain in the wake of gravel pit excavation, which Juvenile Red-backed Shrike. This species Regularly occurring species created suitable breeding habitat. Collared ceased to breed in Of the 215 regularly occurring species, Dove's colonisation of the whole of Kent during the 20th 119 (55%) are thought to be present in mainland Europe and Britain through the century broadly similar numbers in 2010 as in 20th Century was driven by unknown 1900, though some, such as Pochard, factors. Thirty-seven regularly occurring Guillemot and Whitethroat have shown species have decreased or been lost major increases and decreases over that entirely to Kent. The losses include three time. for which the trends seem to be habitat- related, though with climatic influences: Fifty-nine species have increased Wryneck and Red-backed Shrike, and Cirl markedly over the period, 10 of these Bunting. Kentish Plover has been lost being new arrivals. Four of these new because of disturbance in its coastal arrivals (Canada Goose, Mandarin Duck, breeding areas, while for Willow Tit the Ruddy Duck and Ring-necked Parakeet) cause is unknown though possibly are introduced species, reflecting the fairly habitat-related. Thus, there appears to be recent development of the practice of a number of common patterns in the keeping a wide range of exotic birds in trends and their causes:
1909-1953 1953-1976 1976-2010 Current trend
Regularly breeding species Little change Increase Decrease Total Regularly species Little change Increase Decrease Total All species Little change Increase Decrease Total
The numbers of species showing positive and negative population changes over the last century
20 Kent’s Birds Andrew Henderson, Kent Ornithological Society
Thirty-seven regularly occurring species • Changes in farming practice have have decreased or been lost entirely to deleteriously affected a large group of Kent. The losses include three for which species including Grey Partridge, the trends seem to be habitat-related Starling and Yellowhammer, which have though with climatic influences: Wryneck lost suitable nesting and feeding habitat. and Redbacked Shrike, and Cirl Bunting. Kentish Plover has been lost because of disturbance in its coastal breeding areas, The development of gravel extraction has while for Willow Tit the cause is unknown led to a major increase in freshwater though possibly habitat-related. bodies, and has benefited a large group including Great Crested Grebe, Tufted Thus, there appears to be a number of Duck and Coot. common patterns in the trends and their causes: The table on the previous page summarises the number of regularly • Climate change appears to be causing occurring species positively and negatively decreases in a group of species, such affected by the changes described above. as Turtle Dove and Spotted Flycatcher, because of impacts on their African Breeding species wintering grounds. At the same time, Of the 142 regularly breeding species, 55 climatic amelioration in Britain and are thought to be present in broadly Europe has assisted increases in a similar numbers in 2010 as in 1900, separate group, including Avocet and though some such as Sparrowhawk or Green Woodpecker. Lesser Redpoll have shown major increases and decreases over that time. • Declines in persecution have contributed Fifty species are thought to have to the increases of several birds of prey, increased markedly over the period, Carrion Crow and other species. including 25 which were completely new
Factor Number of Number of increasing species decreasing species
Climate change & African 78 habitat change
Disturbance, persecution 75
Habitat & land use change 13 13
Mixtures of the above 90
Introductions 17 3
Uncertain 68
Causes of positive and negative population changes in regularly occurring species
21 Photo: Andy Vidler
Kent’s Birds Andrew Henderson, Kent Ornithological Society
as breeding species in Kent. Six of the because their breeding colonies are species gained as breeding birds were, at protected or are no longer raided for eggs. least to begin with, escapes from captivity or deliberate introductions, and most are Thirty-seven regularly breeding species geese or ducks which have also benefited have decreased, and 10 species no longer from the growth of wetland habitats, from breed in the county. Habitat change, gravel-working and similar activities. The particularly as a result of changes in creation of new wetlands by gravel farming practice, is responsible for most Great Crested Grebes extraction or deliberately for nature losses and population declines. Species have benefitted from conservation purposes has also been a affected include Lapwing and Snipe, the creation of gravel pits major factor behind many of the other affected by loss of wet grassland, and gains to the county breeding bird especially those affected by reductions in community, including Tufted Duck, either winter or nestling food abundance Cormorant, Bittern, Little Egret, Great (or both), such as Grey Partridge, Song Crested Grebe, Marsh Harrier, Avocet, Thrush and House Sparrow. In some Little Ringed Plover, Mediterranean Gull, cases, habitat change impacts have been Bearded Tit, Cetti’s Warbler and Savi's exacerbated by climatic factors; the Warbler. disappearance of Cirl Bunting was probably due to cold winters exacerbated Other gained species are Buzzard by habitat change, while Wood Warbler (responding to lower levels of may be more affected by habitat change persecution), Fulmar and Kittiwake in its African wintering grounds than local (responding to changes in marine food factors. Stone-curlew and Kentish Plover availability – Fulmar in particular is believed have been lost because of disturbance in to have benefited from the increase in fish their breeding areas, compounded by offal dumped from fishing boats), Firecrest farmland changes in the case of Stone- (dependent on 20th century conifer curlew. Most of the losses from the list of plantations), Black Redstart (which regular breeding species seem to be colonised bomb-damaged and industrial habitat-related though with climatic areas after World War Two), and Common influences: Corncrake, Guillemot, Gull and Collared Dove (for which the Wryneck, Red-backed Shrike, Whinchat, causes of colonisation are unclear). and possibly Willow Tit.
Increases associated with climate change Decreases believed to be caused in large are found among shorter-distance part by climatic changes or problems in migrants or sedentary species, which have Africa are found primarily among trans- benefited from milder winters (and often Saharan migrants, including Cuckoo, Tree from other factors such as greater Pipit, Willow Warbler and Spotted availability of suitable habitat). Examples Flycatcher. In some cases, subtle changes are Little Egret, Mediterranean Gull and in climate on the breeding grounds, as Green Woodpecker, and Blackcap and well as habitat changes, may have been Chiffchaff are assumed also to be in this partly responsible, along with changes in category. Africa; Wryneck and Whinchat, for example, are in this group. Quite a number of species have increased through reductions in direct persecution. As for the regularly occurring species, the These include around five birds of prey table below summarises the number of such as Marsh Harrier, Buzzard and regularly breeding species positively and Peregrine, as well as Magpie and Carrion negatively affected by the changes Crow. Several gull species, and perhaps described above. also Sandwich Tern, have increased
22 Kent’s Birds Andrew Henderson, Kent Ornithological Society
Conclusions Similarly, the two main factors believed to Overall, for both breeding and other be linked with increases in breeding species, the two major factors believed to species are (a) the increased availability of be linked with declines in bird species are wetland habitats (in the form of gravel pits, (a) changes in farming practice in Britain, managed wetland nature reserves, affecting nestling and adult survival, and reservoirs and similar) and (b) reduced (b) changes in conditions in African persecution of birds of prey and gulls. wintering grounds of long-distance These affect over half of the species summer migrants, often accentuated by identified as increasing or gained by the climate change. These jointly affect about Kent breeding bird community. The next two-thirds of the species identified as most important factor is judged to be decreasing or lost from the Kent breeding climate change, especially the occurrence bird community. of milder winters.
Factor Number of Number of increasing species decreasing species
Climate change & African 710 habitat change
Disturbance, persecution 11 4
Habitat & land use change 14 15
Mixtures of the above 33
Introductions 90
Uncertain 65
Causes of positive and negative population changes in regularly breeding species
23 Kent’s Birds Andrew Henderson, Kent Ornithological Society
The changing fortunes of regularly occurring species over the last 100 years
The changing fortunes of regularly breeding species over the last 100 years
Over the century or so since 1900, an insignificant decrease, and in 1976 it species’ fortunes seem to have been fairly was locally common, found in 367 tetrads evenly matched, with gains and increases and with a county population of up to slightly more numerous than losses and about 1,000 singing males. We have decreases. This conclusion does, though, suspicions that there was a major need to be qualified in two important decrease during the mid part of the respects. century, but have no hard evidence for this and so have classed this species as ‘no First, there is a strong possibility that the change’. Thus, the imprecision of status qualitative descriptions of species’ descriptions may well have obscured abundance on which we have relied until many real changes. around 1970 are insufficiently precise to infer actual changes. Thus, a bird may be The second point is that at present, a described as very common in both 1909 number of species have different trends and 1953, despite having increased or from those typical of the past 30 years. decreased significantly. As an example, Our estimates of changes between 1976 Nightingales were described in 1909 as and the present cover the whole of that being almost universally distributed and period, but we have also been able to locally numerous, while in 1953 it was well assess current trends – for the last ten distributed and abundant, having shown years or so – thanks to the large amounts
24 Kent’s Birds Andrew Henderson, Kent Ornithological Society of survey data now available. Current and introduced species. The upper graph trends have reversed the balance, as on the preceding page shows how the shown in the first table in this chapter. fortunes of the 215 regularly occurring Amongst ‘regular’ species, for example, species have changed over time, while the 52 species are now judged to be lower graph does the same for regularly decreasing and 18 increasing contrasted breeding species. It is clear that, while the with 47 and 69 respectively over the number of species showing a population whole of 1976-2010. increase varies over time, there has been a steady increase in the number of This change is due primarily to the species showing a decline, and this is reversed fortunes of wintering wildfowl particularly acute in species that breed and waders, most of which had been regularly in the county. increasing steadily from the 1960s or 1970s but went into decline during the It is a common attitude of conservationists 1990s. At the same time, the declines in - and perhaps of people in general – to farmland birds and trans-Saharan believe that things are getting worse, but migrants and a few other groups show no for birds in Kent a great deal of evidence sign of ending. These are not offset by shows that this is the case. increases in a few birds of prey, wetland
25
Photo: Kent Bat Group
Kent’s Bats Shirley Thompson, Kent Bat Group
Bat populations are believed to have box on the following page) considered to undergone major, long-term declines. occur regularly in the UK. This is certainly the case for some species such as the Greater and Change in bat populations Lesser Horseshoe bats, which both Probably three, and certainly two, became extinct in Kent during the species of bat were lost to Kent during 20th Century. the 20th Century. These were: The Alcathoë Bat was only recognised as For a number of species, national Greater Horseshoe Bat separate species in trends show declines are levelling off, In the 19th Century, Greater Horseshoe 2010 or even reversing. As a result, Bats were reported as abundant in populations of some species are Rochester and Canterbury Cathedrals, starting to recover. However, the and there were at least five other records picture in Kent is bleaker, with on- at sites in Kent. The last definite sighting going declines in species whose was a single bat seen closely in 1909 in populations are more stable elsewhere Sevenoaks.
The way in which bats use the Lesser Horseshoe Bat landscape makes them vulnerable to The last and the only positive record of habitat loss and fragmentation, and the species in Kent is of a male taken particularly to agricultural from hibernation in old stone mines in intensification. It also means that Maidstone in 1954. They are now mainly localised change can have wide confined to Wales, western England and impacts. Even where populations now western Ireland. appear stable, this is against a background of long-term decline, and Barbastelle even the most common species may The first Barbastelle in the UK was be vulnerable to future population discovered at Dartford in 1802, but nearly loss. 100 years passed before the second was found at Allington, Maidstone. The most recent confirmed record for Kent was of The small size of bats, their power of a male found dead in High Halstow flight, their nocturnal and secretive way of Church in 1950. However, analysis of life and their vulnerability to disturbance bats’ echolocation calls at Haysden Lake all combine to make bats particularly in September 2009 suggests that the difficult to study. In addition, some species may still be present in the county, species show close physical similarities though this has not been confirmed. so that what was previously considered a single species has sometimes been Many – probably most – of Kent’s found to be two or even three separate remaining bat species are likely to have species, each with slightly different undergone substantial reductions in ecological requirements. The Pipistrelle population during the 20th Century. was recognised as actually comprising However, providing an overview of two species, the Common Pipistrelle and changes over the last 100 years is the Soprano Pipistrelle, in 1997. problematic. Before the early 80s, when Whiskered and Brandt’s Bats were first protection of all species became law, identified as separate species in 1970, there were few studies of bats and no while the Alcathoë Bat was only baseline by which to judge them, as so separated from the Whiskered Bat in much of the information prior to that 2010. period is anecdotal. A lack of systematic data, except in the latter few decades of Nonetheless, there are records from Kent the century, makes it difficult to establish for all eighteen species of bat (see the definite, long-term population trends.
27 Photo: Kent Bat Group
Kent’s Bats Shirley Thompson, Kent Bat Group
Bat species recorded in Kent dramatically in the last few decades, with Asterisked species are those species reports indicating a decline of some 60% currently occurring in Kent and used as in the size of the UK population. However, biodiversity indicators by Defra. Common Pipistrelle populations have started showing signs of recovery in Greater Horseshoe Bat Rhinolophus recent years, with annual increases of ferrumequinum – extinct around 6% a year indicated by field counts. Noctule Bat Lesser Horseshoe Bat Rhinolophus hipposideros – extinct Soprano Pipistrelle This species was only recognised as Daubenton’s Bat Myotis daubentonii* distinct from Common Pipistrelle in the 1990s. It is assumed, from current Brandt's Bat Myotis brandtii knowledge, that the very large summer roosts of Pipistrelles which were not Whiskered Bat Myotis mystacinus unusual 50 years ago were of Soprano Pipistrelles. Several such roosts of about a Alcathoë Bat Myotis alcathoe thousand bats were recorded by Kent Bat Group in the early 1980s. Though the Natterer’s Bat Myotis nattereri largest known maternity roost in the South East, of over 1,000 adult females, appears Bechstein’s Bat Myotis bechsteinii to be stable, the average size of maternity roosts is now much lower. This appears to Greater Mouse-eared Bat Myotis myotis reflect what is apparently a national – status as a resident UK species decline in this species’ numbers, and uncertain therefore this is a species of possible concern. Noctule Bat Nyctalus noctula* Noctule Bat Leisler’s Bat Nyctalus leisleri Brian Vesey-Fitzgerald, in the first book to be published devoted to British Bats (in Serotine Bat Eptesicus serotinus* 1949, when only twelve species were described) wrote of Noctules Common Common Pipistrelle Pipistrellus and widespread in wooded districts of pipistrellus* Southern England’. Today this is a species considered nationally of possible concern. Soprano Pipistrelle Pipistrellus A decline in Noctules was noted and pygmaeus* commented on in Kent in the early 90s, before it was recognised in other parts of Nathusius’ Pipistrelle Pipistrellus nathusii the country. These bats are now considered scarce in the county, with only Brown Long-eared Bat Plecotus auritus single bats or small numbers seen occasionally. No stable maternity roosts Grey Long-eared Bat Plecotus are recorded at present. This does not austriacus – probably not resident in Kent reflect the national trend, which shows a slight population increase over the last five Barbastelle Barbastellus barbastellus – years. extinct (Possibly still present) Serotine Bat The National Bat Monitoring Programme Common Pipistrelle (NBMP) suggests populations are stable Nationally, Pipistrelle numbers declined (at least until more conclusive evidence
28 Photo: Kent Bat Group
Kent’s Bats Shirley Thompson, Kent Bat Group
emerges from the trends). However, in Nathusius’ Pipistrelle Kent the decline is still giving cause for Initially this species was regarded as a concern. A number of roosts where bats vagrant, then as a winter-visiting migrant have been recorded in the last 20 years which came to the UK to hibernate. appear not to have been used recently. However, since the 1990s a small number Numbers at several of those monitored of maternity colonies have been recorded, each summer have declined, some to and there appears to be a migratory Nathusius Bat single figures. One roost in East Kent has population during autumn and winter, and been monitored since 1986, when 62 a small summer breeding population. The adults were counted out, our maximum increase in records in the British Isles may count. In 2010 there were 29 adults. reflect sampling effort, but there is a possibility that the species range is Daubenton’s Bat expanding. The species may also have Daubenton’s Bats are very dependent on been previously under-recorded until the lakes and waterways, feeding on insects more widespread use of bat detectors close to the water’s surface, although they and sound analysis software. Although no will also feed in woodland. The NBMP breeding colonies have been found in the waterways survey indicates significant county, Kent appears to be a significant increases. In Kent, these bats can be county for this species, with a seen over most waterways in summer, comparatively high number of records. In and are also the most commonly recorded 2009, the NBMP set up a new monitoring species found hibernating in underground system for the species, but it will be sites such as tunnels and deneholes. several years before a trend will emerge However, at present only one summer from the results. maternity roost is known in the county. Natterer’s Bat Brown Long-eared Bat Natterer’s Bats are found throughout most After the Pipistrelles, this is the most of the British Isles; it is generally a scarce abundant bat in the UK, but it appears to and poorly known species, but the British have undergone a major decline during population is internationally important. the 20th Century. NBMP data suggests Population trends are unclear and that this decline has levelled and numbers are assumed to be stable until stabilised. However, in Kent, evidence of more conclusive evidence emerges from the species’ past presence, in the form of the NBMP data. In Kent, most records of old droppings, has been found in many this bat are in hibernation at underground houses and other buildings where bats no sites. Almost all summer records are of longer appear to be present, or are only bats found during demolition or present in very small numbers, so there is conversion of barns, or surveys prior to still cause for concern in Kent. conversion, when the roost is about to be lost. Leisler’s Bat Leisler’s Bat has been considered rare in Whiskered and Brandt's Bats most of the UK. However, there is a In Kent, most records are from hibernation suggestion that their numbers may be sites, mainly tunnels and deneholes, increasing as Noctules decline, their use where they have been recorded as of buildings giving them an advantage. In Whiskered/Brandt’s as they are never Kent, known maternity roosts appear to handled for close inspection while have been lost or relocated as a result of hibernating. Both species have been building the Channel Tunnel Rail Link and considered rare in the county, and they possibly the recent M2 widening. appear to have undergone a long-term Nonetheless, there have been more decline during the 20th Century. validated records of Leisler’s in the last five years, with the majority in the north- However, during a survey of woodland west of the county. bats (2009-2010) Whiskered bats were
29 Kent’s Bats Shirley Thompson, Kent Bat Group
the second most frequently trapped after sites. Bats navigate between feeding and Brown Long-eared bats, suggesting they roosting sites by following physical are more abundant than previously features such as hedges and tree-lines. thought. Nationally, populations now appear to be stable. Bats are long-lived, produce small numbers of young, and are faithful to Bechstein’s Bat traditional feeding and roosting sites. They Bechstein’s is one of Britain’s rarest are therefore very vulnerable to change, as mammals, with only six breeding if even one of the places on which they populations (in the whole UK) known in have depended is lost or degraded – even 2005. Bechstein’s was first recorded in just a particular hedgerow lost – their Kent in 1999, hibernating in a denehole, breeding success may be reduced or their with up to four individuals hibernating there very survival threatened. in subsequent years, probably males. In July 2009, a lactating female was trapped The following are likely to have, or have in West Kent during a targeted survey. had, the most impact on bat populations: Most recently two male and one female Bechstein’s were among bats trapped Changes in land use practices during swarming outside Westerham Agricultural intensification has probably Mines in September 2010. The rarity of had the greatest impact on bat this species makes population trends populations, by reducing the diversity and impossible to assess, but the species’ abundance of insect prey through apparent reliance on closed-canopy, agricultural improvement of grassland and undisturbed woodland probably makes it its conversion to arable, and through loss one of the UK’s most threatened animals. of important habitats such as ponds and hedgerows. Because prey items vary with Alcathoë Bat different bat species, so certain agricultural This species is very similar in appearance practices affect some species more than to the Whiskered bat, and only recognised others: for example, the decline in larger as a UK resident in 2010, using DNA bats such as Serotine and Noctule is likely analysis. One was trapped in Kent in July to be related to reduction in cattle grazing 2010 during survey work for other species, and increased use of avermectin-based and was verified from photographs by wormers (which persist in dung), and the Prof. John Altringham. Its status in the UK subsequent reduction in dung and and Kent is unknown. grassland beetles on which the bats feed.
Causes of change in population status Use of insecticides Bats have three major needs: Bats have very high energy requirements, so need to eat huge numbers of insects. Suitable roosting sites. Roosts include Insecticides reduce the availability of food. maternity sites used by females to give In addition, the accumulative effect of birth and raise young, spring gathering pesticides in their fatty tissues, on reduced roosts, mating roosts, night roosts, and fitness and breeding success, is not fully hibernation roosts. Some hibernation sites known. Research in 1972 at an intensively are also used for autumn ‘swarming’ by farmed area of England found bats were some species, an important social activity more heavily contaminated with residues which is little understood. of DDT than insectivorous or carnivorous birds. • Good foraging areas within commuting distance of their roosts. All UK bats feed Loss of roosts in buildings on insects, eating large numbers to It was only with the Wildlife and provide the energy needed for flight. Countryside Act 1981 that bats and their • Safe links between roosting and foraging roosts received protection. Prior to that
30 Kent’s Bats Shirley Thompson, Kent Bat Group time, deliberate exclusion or destruction of whose preferred prey are insects with bats in houses and other buildings aquatic larvae (Soprano Pipistrelle, undoubtedly had an impact on local Nathusius’ Pipistrelle, Daubenton’s and populations. Further impacts came from Natterer’s). the use of timber treatments (such as Lindane) which were highly toxic to Although many bat species have mammals. While more closely regulated, undergone long-term population declines, loss of roost sites still occurs as a result of these appear to be levelling off (at least built development from road schemes to nationally) and population gains are barn conversions. Natterer’s and Long- actually being made. The role of eared Bats are particularly vulnerable to agri¬environment schemes, such as the latter as they are faithful to traditional Countryside Stewardship and roosts over periods of many years. Environmental Stewardship in this partial Unpopularity of bats based on fear and recovery is unclear, though they are likely misunderstanding can still be a threat to to have had a positive impact; the same is bats roosting in houses, when direct probably true of the recent and very action may be taken to exclude them. significant reversal of the historic decline in Legal exclusion is carried out in certain hedgerows and recent increases in water circumstances under licence. quality.
Habitat fragmentation Factors which have clearly been of value Roosting sites and foraging sites must be are: close enough to enable bats to travel economically (in energy terms) between Legislation to protect roosts one and the other with safe commuting Wildlife legislation has made bats among routes linking them. In particular, foraging the best-protected mammals in Britain. sites close to the maternity roost are This has reduced substantially the casual essential for young just learning to fly and destruction of roosts. Important indirect echolocate. Fragmentation of remaining benefits are (a) direct contact with the habitats has undoubtedly contributed to general public through the roost visitor the long-term decline of many species. license system, and (b) contact with professional sectors such as timber- Inappropriate management and loss of treatment companies, builders and woodland forestry. Whilst management such as coppicing may help some species of bat and other Education wildlife, others, such as Bechstein’s and Public awareness has been raised Natterer’s, require more structured, less nationally and locally. The Bat disturbed and dense woodland with many Conservation Trust runs a series of mature trees. The preponderance of courses - targeting professionals and coppice management in much of the UK others - on bats, their legal protections may well be a key reason why Bechstein’s and their conservation needs. In the bat is so rare here. Even for species which county, Kent Bat Group is raising do better in more intensively managed awareness through bat walks for the woodland, removal of older trees with general public and talks to a wide range of cracks and holes may result in loss of audiences including schools, gardening important roost sites. societies, natural history societies and others. There is always a very positive Changes in water quality reaction from the varied audiences. Deterioration in water quality and loss of marginal vegetation can lead to reductions Research in the abundance and diversity of insect Many studies are now being undertaken prey. This is especially important to bats which are helping to inform conservation
31 Kent’s Bats Shirley Thompson, Kent Bat Group
actions. These include a recent national UK's Bats. National Bat Monitoring survey of Bechstein’s Bat. Programme Population Trends.
Monitoring Programme Vesey-Fitzgerald, B. (1948). British Bats. This is providing a baseline for population Methuen & Co Ltd. studies, and acting as an early warning system for problems. Kent Bat Group Harris, S. et al (1995). A review of British inputs data each summer on Common, mammals: population estimates and Soprano and Nathusius’ Pipistrelles, conservation status of British mammals Serotine, Noctule, Brown Long-eared and other than cetaceans. JNCC. Daubenton’s Bats, and on hibernating bats each winter. Haysom, KA, Jones, G, Merrett, D & Racey, PA. (2010). Silent Summer – The Much more work will be required to State of Wildlife in Britain and Ireland, maintain and improve diversity of this Cambridge University Press. 259-280. highly vulnerable group, which is itself an important indicator of the wider health of Heathcote, PC & Heathcote, P. (1994). the environment. This should include The Bats of Kent. Kent Field Club. further research and data collection to assess trends and highlight particular Jeffries, DJ. (1972). Organochlorine problems; continued monitoring of known insecticide residues in British bats and sites; ensuring the needs of bats are taken their significance. Journal of Zoology into account in habitat management, Society of London. especially in the case of woodland where this is increasingly well understood; and Kent Bat Group records database 1980 - planning and delivery of habitat restoration 2010. at a landscape-scale. Waite, AR (ed). (2000) Kent Red Data Book. Kent Wildlife Trust & Kent County References Council Altringham, JD. (2003). British Bats. Harper Collins.
Bat Conservation Trust. Species descriptions, downloadable at www.bats.org.uk
Bat Conservation Trust. The State of the
32
Photo: R I Moyse Kent’s Wild Plants Richard Moyse, Kent Wildlife Trust
Between 1900 and 2010, more than 30 plant species had appeared before 1900. wild plants were lost from Kent. The In the eight decades between 1900 and rate of plant extinction accelerated 1980, 21 species became extinct in the over the course of the 20th Century. county, an average of 2.6 species a decade. Since 1980, the rate of extinction Habitat loss has been a major appears to have accelerated, with 12 contributor to plant population species vanishing from Kent, an average declines. Particularly hard-hit during of 4 species per decade. Annual Knawel, a the 20th century have been plants of plant of open, dry wetlands, heathlands, and meadows. The causes of these extinctions may habitats never be entirely clear. Many of the Changes in habitat quality have also species now extinct were always rare in had an impact. Wildflowers of arable the county, and may simply have farmland have suffered massive succumbed to chance events. However, declines due to changes in farming the loss of species such as Field Fleawort practices. Data suggests that other Tephroseris integrifolia, Moonwort changes associated with farming and Botrychium lunaria, and Small Fleabane development, such as increased Pulicaria vulgaris suggest one possible nutrient availability and the drying-out cause is change in the management of of wetlands, continue to contribute to grassland. Perhaps more significant have declines in wildflowers. been changes to wetland habitats and systems. The loss of Marsh Gentian Over 2,000 species of plant have been Gentiana pneumonanthe, Broad-leaved recorded in the wild in Kent. These include Cottongrass Eriophorum latifolium, Fen some 950 native plant species, around Orchid Liparis loeselii, and Shoreweed, 130 ‘archaeophytes’ (ancient Littorella uniflora, all suggest that loss of introductions which have been long- wetlands (either by drainage or established in the UK, such as field poppy abandonment) has been very significant, and cornflower) and over 1000 recently and may have been a factor as far back introduced species. It is the native plants as the early 19th Century, if not earlier. and archaeophytes which we generally think of as ‘wildflowers’, and it is these Habitat loss which are considered in this paper. The Extinction of individual species is only the information presented in this paper is very coarsest measure of change in plant primarily derived from the Atlas of the Kent populations. Absolute change in the Flora, published in 1982, and 2010’s A abundance and distribution of wild plants New Atlas of the Kent Flora; both books is difficult to assess. Because distribution are by Eric Philp and published by Kent maps (or descriptions) indicate only the Field Club. Considerable use has also presence or absence of a plant within a been made of the Flora of Kent of 1899, given area (in the case of the most recent by Frederick Hanbury and Edward plant atlases of Kent’s flora, a 2km by Marshall. 2km square) substantial changes in abundance can occur without being Extinctions clearly apparent; a species may be Kent’s wild flora has become increasing marked simply as being present in an area impoverished over time. One hundred whether there are 10,000 individuals or native or archaeophyte species which just one. once occurred in Kent – 10% of all such species recorded – are no longer found So, although past habitat loss will here. Some of these disappeared many undoubtedly have resulted in reductions in years ago: for example Water Avens populations of many species, this may not Geum rivale was last recorded in Kent in be apparent from distribution maps if the the 1,770s, and 32 previously recorded remaining habitat fragments are widely
34 Kent’s Wild Plants Richard Moyse, Kent Wildlife Trust spread. For example, plants associated Stachys arvensis (common throughout the with ancient woodland have largely county in the 19th Century, and showing a maintained their overall distribution in the 75% decline in distribution since 1980), county even while there has been a and Shepherd’s Needle Scandix pecten- substantial drop in habitat extent. veneris (common throughout the county in the 19th Century, now only recorded from For some wild plants though, the extent of three tetrads). habitat loss has been so extreme that they have disappeared from wide areas of Factors implicated in plant declines countryside. 90% of the heathland Information on the relative decline of present in 1798 was lost in the following particular plant species can be obtained 200 years. Alongside this have been clear by comparing the number of 2km by 2km declines in heathland plants such as Petty squares (tetrads) occupied by a species in Whin Genista anglica, and plants of open, the Atlas of the Kent Flora of 1982 and A acidic habitats, such as Annual Knawel New Atlas of the Kent Flora of 2010. By Scleranthus annuus. At the end of the subjecting the data to the same analysis 19th century, Annual Knawel was noted used in the New Atlas of the British and as locally plentiful on sites across Kent, Irish Flora, it is possible to calculate a but is now known only from 5 tetrads in ‘change index’; this does not give the county; nationally, it is formally listed absolute change, but allows some as Endangered. conclusions to be drawn about relative ‘winners’ and ‘losers’. In addition, by Likewise, the historic, and undoubtedly comparing change indices for large severe, loss of traditional hay meadows numbers of species against other and unintensively managed grassland environmental information, it is possible to shows in the distribution of plants draw some broad conclusions about the associated with these habitats. Green- nature of environmental change in the winged Orchid Orchis morio is reported in county. the 1899 Flora of Kent as ‘common, particularly on chalk and wealden clay’, Extinctions of wetland plant species are and Dyer’s Greenweed Genista tinctoria is discussed above. It is also the case that, ‘frequent in several districts’; both are of the 50 species showing the greatest plants of very restricted distribution today. relative decline between the 1982 and Likewise, Meadow Saxifrage Saxifraga 2010 atlases, 16 are wetland plants. granulata was ‘locally plentiful’ in the 19th These range from fully submerged Century, but is now very scarce, with just species, such as Opposite-leaved a few sites in the west of the county. Pondweed Groenlandia densa, through emergent species such as Water-cress The suite of annual plants associated with Rorippa naturtium-aquaticum, to plants of arable fields has shown even greater loss. wet grassland, such as Marsh Arrow- Of the 50 plant species which have shown grass Triglochin palustre. the greatest relative decline in the county over recent decades, 12 are arable The relative decline of plants of wet ‘weeds’. These include Corn Buttercup habitats is well illustrated using Ellenberg Ranunculus arvensis (common and found values. Ellenberg values are assigned to across Kent during the 19th Century, but individual plant species and indicate the perhaps now limited to one site), tolerance of that species to certain Pheasant’s Eye Adonis annua (well environmental conditions. For example, established in some places on the chalk, Ellenberg values for moisture range from 1 according to the 1899 Flora of Kent), Red (plants of extremely dry sites) to 12 Hemp-nettle Galeopsis angustifolia (submerged plants found permanently or (frequent in cornfields and on shingly almost permanently under water). Plotting beaches in the 19th century, now only Ellenberg values for moisture against the found at Dungeness), Field Woundwort mean change index for all native or
35 Kent’s Wild Plants Richard Moyse, Kent Wildlife Trust
Positive and negative change in Kent’s wild plants in relation to soil moisture conditions, from very dry (2) to submerged (12)
Positive and negative change in Kent’s wild plants in relation to soil fertility, from very low nitrogen content (1) to very high nitrogen content (9)
Positive and negative change in Kent’s wild plants in relation to soil pH conditions, from very acidic (1) to highly alkaline (9)
36 Photo: R I Moyse
Kent’s Wild Plants Richard Moyse, Kent Wildlife Trust
archaeophyte plants with that value, we species at least, this decline is related get the top chart on the previous page. more to decline in habitat quality than to This shows that plants of averagely moist loss of habitat extent. This may include to damp soils (Ellenberg values of 5 to 7) declining plants such as Meadow Oat- have generally increased in distribution, grass Helictotrichon pratense, Silver Hair- while plants of wetter situations have grass Aira caryophyllea, Musk Orchid declined. Note that this graph excludes Herminium monorchis, and Dodder Lizard Orchid, a plant Least Duckweed Lemna minuta, an Cuscuta epithymum. showing a recent invasive, non-native wetland plant which increase has spread rapidly in recent years; if this is Plant population increases included, a slight increase is shown What of the winners? Which plant species against the value of 11. might be increasing? This paper does not, in general, deal with recently introduced Plotting change indices against Ellenberg species to the UK, although half of the values for nitrogen (effectively an indicator plant species occurring in the wild in Kent of the soil fertility with which individual were introduced to the county in historical species are associated) also gives an times, and some very recently indeed. indication of how Kent’s environment may Recent arrivals often tend to spread be changing. The centre chart on the rapidly, and this has been the case in a previous page shows the apparent decline number of species in the county. Narrow- of plants of very infertile sites (value 1) and leaved Ragwort Senecio inaequidens, a the apparent increase in plants of very rich South American species, was unknown to sites (value 9) – though the number of the UK in Victorian times, and was only species in each of these categories (12 recorded from a single site in the 1982 and 5 respectively) is small. Atlas of the Kent Flora. Now it is recorded from at least 15 tetrads. Least Duckweed Likewise, in the bottom chart on the Lemna minuta, a tiny, floating wetland previous page, only one species in Kent plant, was first recorded in the Kent in (Dwarf Gorse Ulex minor) has an Ellenberg 1981. The 2010 New Atlas of the Kent pH value of 1 (plants of extremely acidic Flora shows it as present in 330 tetrads – soils), and relatively small numbers (14 one-third of the total and 25 respectively) have values of 2 and 3. Seven species have a Ellenberg pH Of the 50 native and archaeophyte value of 9, being associated with very ‘winners’ – those plants showing the calcareous soils: these include Lizard greatest positive change between the Orchid Himantoglossum hircinum, a 1982 and 2010 atlases – a number species which has increased substantially appear to be plants which have become in recent years, probably in response to increasingly rare but which may now be climate change. Nonetheless, there does staging a slight comeback, such as appear to be a decline in species Stinking Goosefoot Chenopodium associated with more acidic conditions. vulvaria, Rye Brome Bromus secalinus, Field Garlic Allium oleraceum and Wild Graphs like these need to be interpreted Candytuft Iberis amara. However, there do with a certain amount of care. However, appear to be some significant gains by what they seem to suggest is that the plants which were historically rare in Kent, plants which have declined most, at least including Oak-leaved Goosefoot since 1980, are those associated with the Chenopodium glaucum, Lesser Centaury ends of the spectrum of environmental Centaurium pulchellum and Lizard Orchid conditions in the county. So species of Himantoglossum hircinum. Lizard Orchid wet, very dry, acid, calcareous, or low is discussed above, and Lesser nutrient situations have declined relative to Centaury’s increase may be related to an the rest of the county’s flora. It also seems ability to colonise disused quarries and likely to be the case that, for some other post¬industrial sites. Some formerly
37 Photo: R I Moyse
Kent’s Wild Plants Richard Moyse, Kent Wildlife Trust rare species are now widespread, have been refound. The rate of loss of particularly Prickly Lettuce Lactuca plant species is lower for Kent than for serriola and Great Lettuce Lactuca virosa. many other counties, where geology and land-use history has encouraged much In addition, some (though very few) more intensive agricultural exploitation. species previously considered extinct have reappeared, and there have been However, past loss of habitat has some genuine colonisations by species undoubtedly reduced Kent’s plant Shepherd’s Needle, a never previously recorded here. For populations, even if many species remain declining wildflower of example, Pennyroyal Mentha pulegium widespread. Population declines are arable fields has been found at Sevenoaks Wildlife continuing and are severe for some Reserve, where it may be an accidental groups of plants, especially wetland plants introduction, Smooth Cats-ear and arable wildflowers. Perhaps most Hypochaeris glabra was discovered near worryingly, there has been an acceleration New Romney in the 1980s, and Shrubby in the rate at which plants are Seablite Suaeda vera (almost certainly a disappearing from the county altogether. genuine, natural colonist) was first recorded in 1964. One of the few species Historic habitat loss has undoubtedly to have apparently returned from played its part in the decline in Kent’s wild extinction in the county is Bog Myrtle plants. But the data show that decline in Myrica gale, rediscovered at Hothfield the availability of wet habitats, low pH Common in 2010, 50 years since it was habitats and low fertility sites have all been last seen. major factors in on-going decline. Our flora is far less rich than it was in the 19th The reasons why some plant species century, and continues to become more appear to be increasing are unclear, and impoverished and homogenous. are not obvious from the Ellenberg values for moisture, nitrogen, pH or light. References However, a suite of native plants Hanbury, F & Marshall, E. (1899). Flora of associated with coastal habitats, and Kent. especially with saltmarsh, have shown substantial expansion of range. These Hill, MO, Mountford, JO, Roy, DB & plants have exploited the margins of Bunce, RGH. (1999). ECOFACT 2a roads, where winter gritting creates saline Technical Annex -Ellenberg’s indicator conditions which most other species are values for British plants. DETR unable to tolerate. These species include Danish Scurvy-grass Cochlearia danica, Philp, EG. (1982). Atlas of the Kent Flora. Lesser Sea-spurrey Spegularia marina, Kent Field Club. and Reflexed Saltmarsh grass Puccinellia distans. Philp, EG. (2010). A New Atlas of the Kent Flora. Kent Field Club. Conclusions There is undoubtedly good news to be Preston, CD, Pearman, DA & Dines, TD. reported. Some declining species are (2002) New Atlas of the British and Irish showing signs of recovery, and some Flora. Oxford University Press. species previously considered extinct
38
Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust
Survey data is not yet sufficiently available. However, national marine detailed or extensive to be able to databases include records of around 700 catalogue losses or increases of different species of marine animals around specific numbers of marine species Kent. from the seas around Kent. These fall into 17 different phyla: What is clear is that the seas all around the UK have suffered serious decline, • Porifera (sponges). with fish stocks falling and habitats Approximatelyimately 40 species being lost or damaged through an ever • Cnidaria (anemones, corals, hydroids, increasing range and intensity of jellyfish). Approximately 65 species commercial and recreational pressures. • Ctenophora (comb jellies). Minimum 2 Several marine species which occur species around Kent are listed as endangered • Platyhelminthes (flatworms). Minimum 1 or vulnerable. Other pressures on species marine wildlife come in the form of • Nemertea (ribbon worms). Minimum 5 pollution and from climate change and species rising sea temperatures, ocean • Entoprocta (small stalked animals with a acidification, and rising sea levels ring of tentacles). Minimum 2 species causing coastal squeeze against hard • Sipuncula (peanut worms). Minimum 4 sea defences. A more recent, yet species significant, threat is competition from • Echiura (spoonworms). Minimum 1 rising numbers of invasive non-native species species. • Annelida (segmented worms). Approximately 170 species The Marine and Coastal Access Act • Chelicerata (including sea spiders). 2009 requires the establishment of an Approximately 10 species ecologically coherent network of • Crustacea (including crabs and Marine Protected Areas, and the barnacles). Approximately 165 species formulation of regional marine plans, • Mollusca (including snails, clams, slugs which could help to reverse the decline, and octopus). Approximately 130 if delivered and managed robustly. species • Brachiopoda (lamp shells). Minimum 2 Marine Species of Kent species Around 250 species of marine algae have • Bryozoa (sea mats). Approximately 50 been recorded in Kent (compared with species about 600 species around the entire UK). • Phoronida (horseshoe worms). Minimum Occurring in roughly similar proportions 1 species nationally, this comprises • Echinodermata (including starfish, sea Approximatelyimately 110 red algae, 80 urchins). Approximately 20 species brown algae and 50 green algae. The • Chordata – Tunicata (seasquirts). county’s marine algae are mapped in An Approximately 20 species Atlas of the Seaweeds of Kent, (Tittley & • Chordata – Pisces (fish). Approximately Price, 1977), and in a significantly 75 species augmented atlas, incorporating a thorough review of past museum and field records It is undoubtedly the case that most of and comprehensive new survey data, in these groups are under-recorded, and that preparation by Ian Tittley for publication in many more species occur around Kent, 2012. This includes several additional but have yet to be recorded. Recent species newly recorded from Kent. intertidal chalk surveys around Dover for example produced new records of eight Unfortunately, a similarly comprehensive sponges, four hydroids and eight survey of each of the disparate groups of bryozoans (as well as several new algae) marine fauna found around Kent is not (Spurrier et al, 2011).
40 Photo: Chris Wood
Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust
Other, more conspicuous marine species floating pontoons of Dover Harbour in and features have also been recorded only 2005. It has not been recorded on within the last decade. In the early 2000s, Kent’s shores, and the record Sabellaria spinulosa (rossworm) had not represents the first record for the been recorded in reef form around Kent, southeast of England of a species but several reef formations have since common in the warmer parts of the been recorded in Seasearch diving and Atlantic Ocean. Shoresearch surveys and in offshore • Einhornia (Electra) crustulenta, an windfarm impact assessment surveys. encrusting bryozoan of estuarine Anemones and sponges Seasearch surveys have also recorded habitats, found on the pontoons in the several occurrences of species not Medway near Chatham in 2011, not previously known to be present in Kent, previously recorded in Kent, and with such as ross coral/potato crisp bryozoan, limited records elsewhere around the Pentapora foliacea, the candy striped UK. It was found with Cordylophora flatworm, Prostheceraeus vittatus, the caspia, a non-native hydroid, and solitary hydroid, Corymorpha nutans, and together these species characterize a seaslug species Polycera faeroensis, rare brackish water community type Polycera quadrilineata and Crimora which has only one other recorded papillata. It is likely that these widespread occurrence in the UK (in a turbid water species were present previously but estuary in southwest England). simply had not been seen or recorded. These species have been found rarely Rare marine species around Kent even during detailed surveys, and were Recent surveys have identified a number not found where comparable surveys of rare species new to Kent, including: were conducted in previous decades. • Craterolophus convolvulus a rare stalked Conversely, some rare species recorded in jellyfish recorded in Fan Bay in 2010, the previous decades have not been recorded nearest other records being in Scotland in more recent surveys. However, in most and Cornwall. cases, this is more likely to represent • Lucernariopsis cruxmelitensis, a stalked serendipitous finds of rare species than jellyfish recorded at Margate in 2001, the arrival or disappearance of the species previously recorded only in Southwest in the area. This reinforces the need for England. further survey. • Halcampa chrysanthellum, an unusual anemone recorded off The Street, The ongoing presence of some rare Whitstable in 2008, for which there are species has recently been confirmed only scattered other records around the through specific surveys, including, a rich UK. and unusual community of burrowing • Caecum armoricum, Defolin’s Lagoon fauna characterised by the spoonworm, snail, recorded in Lydd in 2007, whose Maxmuelleria lankesteri, with the lobe shell known distribution is limited to this Philine aperta, which was found in 2010 location, Pagham Harbour and The Fleet to persist in the muddy sediment in Hythe in Dorset. Bay. • Hermaea bifida, a seaslug recorded at St Margaret’s in 2011 (unusually on the Some generally widespread species are intertidal), for which the scattered found only rarely around Kent. records did not previously extend east of Hampshire. The greensand at Copt Point, Folkestone, • Clathria (Microciona) strepsitoxa, a is particularly notable in supporting sponge recorded on the chalk near species of algae which do not occur Dover in 2010, and at few other anywhere else around the county. For locations previously, all west from example, the brown channel wrack, Hampshire. Pelvetia canaliculata, occurs only at this • Dasya cf ocellata, a small red location, where it forms a discontinuous filamentous alga, detected on the zone near the high tide level. Below this,
41 Photo: B Chapman
Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust
another brown alga, knotted wrack, other locations in Britain where it forms Ascophyllum nodosum, forms a distinct forests). zone on the intertidal, and is found only here or on man-made hard structures in Several species are currently known in the Thames, Medway and Swale on the Kent only from Thanet, including the algae north Kent coast. Copt Point is also the Acrochaetium virgatulum, Chondria only recorded location around Kent for dasyphylla, and Griffithsia devoniensis. Didemnum vexillum Polysiphonia lanosa, which is only found The first studies of the taxonomy and Carpet Seasquirt growing on Ascophyllum nodosum, while ecology of chalk cliff algae were invasive non-native the red algal parasite, Choreocolax undertaken at Westgate and Ramsgate Seasalter polysiphoniae, is found growing on this and these are the ‘type’ localities of Polysiphonia species only. several genera and species of algae, (where they were first found and Other species known only from Copt Point described). are the red alga Lomentaria clavellosa, the brown algal epiphyte, Stictyosiphon The stringy red alga Gracilariopsis griffithsianus, and the brown alga, longissima was first found and described mermaid’s tresses, Chorda filum. The from material collected at Sheerness, and small red alga, Erythrodermis traillii is only it features two small red algal epiphytes known to occur on the greensand Acrochaetium corymbiferum and boulders of Folkestone Harbour wall. It is Aglaothamnion pseudobyssoides that in unlikely that the loss of these species at Kent are largely restricted to this area. this location could be reversed through natural recolonisation, and the area is The red alga Bostrychia scorpioides in highlighted as an Important Plant Area Kent is restricted to saltmarshes and (Plantlife, 2007). occurs only in the Medway and Swale estuaries where it grows on and among A number of algal species are restricted in the sea purslane, Atriplex portulacoides. distribution in Kent to the chalk reefs at Commonly associated with Bostrychia is Langdon Bay and Shakespeare Cliff, another red alga, Catenella caespitosa, either side of Dover, including Apoglossum but this occurs more widely in the county. ruscifolium, Callophyllis laciniata, Dilsea carnosa, Plumaria plumosa, Pterosiphonia A red algal species, Callophyllis laciniata pennata, Rhodophysema elegans, was recorded in Dover Harbour in 2008, Schmitziella endophloea, Scinaia confirming some historic records, and furcellata, and Spermothamnion spp. falling in a gap in the species’ recorded distribution between Yorkshire and the Isle The brown thong weed, Himanthalia of Wight. A brown alga, Desmarestia elongata, is frequently found washed ligulata, was recorded for the first time on ashore around Kent, but has only been natural shores around Kent in 2010, on recorded once in the county in recent the chalk at Folkestone Warren, where it years (in 2006), growing on the chalk falls in a gap in the species’ recorded shore at Langdon Bay. A search in 2007 distribution between Norfolk and Sussex. in the same location failed to find any specimens, suggesting this may have Several species are known only from the derived from viable drift material. There is man-made structures that occur around a gap in the species’ distribution in the the Kent coast. These include the green South East(from Yorkshire to West alga, Gayralia oxysperma, on seawalls in Sussex), which may be attributable to the the Thames and Medway estuaries; the soft and friable nature of most of the brown alga Desmarestia viridis and the red county’s shores (Tittley, 2008). The large Griffithsia corallinoides in Ramsgate brown kelp, Laminaria hyperborea, is also Harbour, the red Dasya cf. ocellata in restricted to the chalk around Dover Dover Harbour, and the red alga, where it occurs sporadically (in contrast to Calliblepharis jubata, in the Walpole Bay
42 Photo: B Chapman
Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust swimming pool. The conspicuous • Undulate ray, Raja undulata blackish-red tufted alga, Spyridia • Basking shark, Cetorhinus maximus filamentosa, has also been recorded in • Tope shark, Galeorhinus galeus the Walpole Bay swimming pool near • Blue shark, Prionace glauca Margate, but not on natural shores around Kent. The record represents the Six of the 29 Marine Conservation Zone eastern limit of distributional range in Species Features of Conservation Britain, and is the first record for Kent and Importance (FOCI) are present around the southeast of England of a species that Kent: Lower greensand occurs widely in the North Atlantic. Laminaria zone • Stalked jellyfish, Haliclystus auricula - a Other algal species currently known from single known site at Westgate, Thanet a single location around Kent comprise • Stalked jellyfish, Lucernariopsis Acrochaetium sparsum, an epiphyte cruxmelitensis – a few records around recorded at Reculver only; Antithamnion Thanet cruciatum, recorded in Dover Harbour • Tentacled Lagoon worm, Alkmaria only; Halopteris filicina, and Punctaria romijni - in the Thames and Medway latifolia, recorded at Abbot’s Cliff only; and • Native oyster, Ostrea edulis – records Hincksia ovata, recorded in Chatham scattered all around the county harbour only. • Defolin’s Lagoon snail, Caecum armoricum – a single known site, in Seagrass beds in the Swale area feature Lydd’s lagoons the finer-leaved Nannozostera noltii and • Short-snouted seahorse, Hippocampus the more robust Zostera angustifolia, both hippocampus – a few scattered records of which are nationally scarce species. around the county
Marine species highlighted for Key marine habitats and communities protection found in Kent Kent’s marine fauna and flora includes a Kent’s seabed features some exposed number of rare or threatened species rock reefs, such as those extending out which have been highlighted for from the chalk cliffs around Thanet and protection. Twenty eight of the UK’s 275 Dover, and the greensand around marine fish are listed as Biodiversity Folkestone. On the north Kent coast, Action Plan priority species, and 15 of London clay is intermittently exposed, these occur around Kent. and, at Reculver, blocks of tabular sandstone overlay clay. These relatively UK Biodiversity Action Plan priority stable rock areas support algae on the species found around Kent: intertidal and shallow subtidal (as far as light penetration is sufficient through the • Stalked jellyfish, Haliclystus auricula typically turbid water). Around and below • Stalked jellyfish, Lucernariopsis low tide the rocks support rich cruxmelitensis communities of attached animal life. • Native oyster, Ostrea edulis • Herring, Clupea harengus Coastal and marine chalk is globally • Cod, Gadus morhua scarce, forming less than 1% of the whole • Whiting, Merlangius merlangus UK coastline, and Kent has 35% of this • Mackerel, Scomber scombrus UK resource. The chalk and clay allow • Horse mackerel, Trachurus trachurus unusual assemblages of plants and • Sea monkfish, Lophius piscatorius animals, adapted to living on and within • Lesser sandeel, Ammodytes marinus the soft rock. In some areas of chalk reef, • Short-snouted seahorse, Hippocampus deep gullies are formed, with shaded hippocampus overhangs created by scouring of the soft • Plaice, Pleuronectes platessa chalk. Further habitat complexity is • Sole, Solea solea provided by the periodic falls from the • Common skate, Dipturus batis chalk cliffs, depositing large boulders out
43 Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust onto the intertidal. These can support sediment. Seagrass beds and extensive unusual and rich communities of attached saltmarsh formations in the Medway animal life on the damp and shaded estuary and the Swale create habitats undersides, featuring sponges, seasquirts which supports different plant and animal and bryozoans in particular. diversity, as well as protected nursery grounds for fish and other species. The Analysis of Kent’s algal distribution data saltmarshes of the Medway estuary and reveals the chalk reefs in Langdon Bay the Swale represent an important and below Shakespeare Cliff, located component of the algal species and either side of Dover, to be the richest in communities of the county, often algal species in Kent, with 90-100 species characterised by green algae and the recorded here (Tittley, in prep.). The coast yellow green algal genus Vaucheria, and of Thanet is recognized to be of supporting the red alga Bostrychia international importance for the rare algal scorpioides. communities on its chalk cliffs, in caves and on the intertidal chalk reefs. While In Hythe Bay stable and unusual floristically not as rich overall as the Dover communities occur in the subtidal mud, area, analysis of Kent’s algal distribution featuring large burrowing animals data reveals the north coast of Thanet to including spoonworms (Maxmuelleria be moderately species rich. lankesteri) and mats of tiny Ampelisca crustaceans. The soft London clay of north Kent is ecologically distinct form the county’s Large areas of Kent’s seabed comprise chalk in lacking the dense canopies of varying coarsenesses of sediment fucoid and kelp algae. Nonetheless the overlying rock in varying thicknesses from clay (particularly that at Studd Hill, thin veneers to deep deposits. In many between Hampton and Tankerton) is of places, the bedrock and boulders are moderate algal species richness. intermittently exposed, providing a rich habitat mosaic of stable rock supporting The small outcrop of lower greensand at sessile animals, with mobile and Copt Point at Folkestone represents a burrowing animals living on and within the single area of harder natural intertidal rock sediment between. around Kent, and is important in supporting algal communities and species The county’s seabed sediment habitats not found on natural surfaces elsewhere are frequently stabilised with formations of around Kent. sand tubes constructed by rossworms, Sabellaria spinulosa. These tubes can Kent seas also hold offshore sand banks, form a stabilising crust over the sediment such as those of the Goodwin Sands and seabed, or in certain conditions they can Margate Sands complexes, as well as the form into reef structures standing several impressively long and tall sediment centimetres proud of the seabed and Photo: Jason Armstrong formation of the Varne Bank in the Dover covering large areas. Sabellaria spinulosa Strait. While sandbank sediments are reefs are usually found in the subtidal, but often mobile, they can also harbour many significant formations are present on invertebrates and fish, and can be intertidal chalk around Kent, at consolidated by beds of mussels and Kingsdown, Deal and Dumpton Gap and reefs of rossworm tubes. Those Birchington on Thanet, representing a sandbanks which are exposed at low tide habitat and community type not included provide remote haul out sites for seals. in the national classification system. The honeycomb worm, Sabellaria alveolata, Mud and fine sand seabeds occur in the more typically occurs on shore in areas of estuary areas of the Thames, Medway, rock and sand, but off Folkestone it forms Swale and Pegwell, supporting high reefs on subtidal muddy sediments, numbers of animals living within the representing another habitat and Mussel bed Mytilus edulis
44 Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust
community type not included in the • fragile sponge and anthozoan national classification system. These communities – on subtidal greensand off Sabellaria formations are delicate, and Folkestone broken sections and collections of broken • intertidal under-boulder communities – tubes are frequently encountered on the Kingsdown to Folkestone seabed. • seagrass beds – Medway and Swale (intertidal beds only) Blue mussels are also present around the • rossworm reefs – records scattered whole Kent coast, forming often long- around the county, both intertidal and lived, stable beds on both rock and subtidal sediment on the intertidal, and sometimes • honeycomb worm reefs – subtidal off more ephemeral features in the subtidal. Folkestone • native oyster beds – north Kent All these types of natural ‘biogenic’ reef • mussel beds – records scattered around formations provide important habitat and the county shelter for a range of small species, which in turn provide a food source for larger The chalk reefs of Thanet, sand dunes of animals. Sandwich Bay, shingle of Dungeness and sandbanks in the outer Thames each fall The many man-made structures that have within Special Areas of Conservation been constructed and the numerous under the European Habitats Directive. wrecks that lie around Kent create The Swale, Medway Estuary and additional hard habitat features, and can Marshes, Outer Thames Estuary, Thanet increase biodiversity locally, although in Coast and Sandwich Bay, and Dungeness some cases (notably coastal protection on to Pett Level each fall within Special chalk coasts) they can cause the loss of Protection Areas under the European natural habitat and communities. Birds Directive. Sites around Thanet, at Folkestone and in the Thames have been Marine habitats highlighted for identified as Important Plant Areas protection (Plantlife, 2007). Biogenic reef habitats are among several of Kent’s marine habitats which have The current status of species been recognised as priority habitats in the There is insufficient data available for a UK Biodiversity Action Plan and more detailed analysis of the state of individual recently for protection as Habitat Features marine species in Kent. Even baseline of Conservation Importance (FOCI) in the data is far from comprehensive, although designation of Marine Conservation Zones the forthcoming comprehensive seaweed under the Marine and Coastal Access Act atlas (Tittley, in prep) will greatly facilitate 2009. future analysis of the county’s marine algal communities. Marine Conservation Zone Habitat FOCI
Photo: B Chapman present around Kent: Certain specific areas of the county have • intertidal chalk – Thanet, and Kingsdown been subject to repeated studies, to Folkestone including Sandwich Bay, Thanet’s • subtidal chalk – Thanet, and Kingsdown intertidal and subtidal chalk and Dover’s to Folkestone intertidal chalk. These studies indicate • subtidal sands and gravels – widespread that most key biotopes and their around the county characterising species (i.e. broadly similar • mud in deep water, and mud with species assemblages) have persisted on burrowing megafauna – Hythe Bay the intertidal chalk around Thanet and • sheltered muddy gravels – scattered Dover. Changes in abundance of several records, including Thames estuary of the species, and large differences in the Pacific Oyster • peat and clay exposures – Folkestone species lists on the subtidal chalk around Crassostrea gigas Epple Warren, and north Kent, west of Thanet Thanet were noted in 2004, compared
45 Photo: B Chapman Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust
with 1997. However, it was concluded and south coasts of England recorded a that there was a constant core community significant decline in the overall catch per over the seven year period, and that unit effort over the time of the survey, changes of the scale observed were likely especially in the young of fished species, to occur on a regular basis. and concluded that fisheries have negatively impacted on the recruitment of It is not possible to determine whether a young commercial fish. general decline in intertidal species Sabellaria spinulosa diversity in recent years perceived by a Certain marine species found around Kent intertidal rossworm number of regular long term marine survey are vulnerable to disturbance and less Kingsdown volunteers is significant, transitory or able to recover (Marine Ecological Surveys permanent. Limited, 2008). Records of species such as the delicate fan worms, Bispira Species losses volutacornis, (identified as vulnerable) Species losses experienced in Kent are around the Kent coast appear to be not easily determined from the data generally restricted to larger rock or wreck available, though some declines are features which are unsuitable for towed notable. fishing gear and therefore provide them with protection from physical damage. The county’s once abundant native oyster beds have been reduced to small pockets A decline or change has been noted in and farmed stocks. Even by 1903, the certain species, such as the widely Sea Fisheries Committee noted that the occurring bryozoan, Membranipora indigenous oyster banks which were membranacea which could not be found previously found here and there all over around Dover on intertidal surveys in the area of the Thames Estuary were now 2009/10, where previously it had been only to be found in the Blackwater and recorded commonly on the intertidal Kentish Flats. Subtidal mussel beds in (Spurrier et al 2011). Similarly, monitoring areas such as the Swale are also noted to surveys of the subtidal chalk around have declined in recent years. Thanet in 2004 failed to find the large aggregations of the seasquirt Molgula Populations of commercially exploited fish manhattensis present in 1995 and 1997. have declined around the UK, to the extent that around half the North Sea’s The Defolin’s lagoon snail, Caecum commercial fish stocks are now ‘outside armoricum, was recorded in Lydd in 2007 safe biological limits’, and the sizes at (Pain et al, 2008). A subsequent SAC which some species breed have reduced. monitoring survey failed to find the Around ten fish species found in English species, and concluded that recent waters are either critically endangered or changes to the lagoon habitat conditions endangered, while fifteen more are may mean the site is no longer suitable. vulnerable to global extinction (Natural England 2010). This includes the critically The peacock tail alga, Padina pavonica endangered European eel, Anguilla has not been recorded in the past century anguilla, the endangered undulate ray, around Kent, while several, sporadic Raja undulata, and the vulnerable Atlantic records exist previous to 1900. Historical cod, Gadus morhua, haddock, evidence also indicates that the red alga Melanogrammus aeglefinus, basking Bostrychia scorpioides has now become shark, Cetorhinus maximus, tope shark extinct on the Kent side of the Thames. Galeorhinus galeus, and smooth hound, Mustelus mustelus, all of which have been Climate change recorded around Kent. Recent surveys have recorded several new arrivals to Kent which represent A young fish survey carried out by Cefas range extensions of native species, over the past 30 years around the east probably as a result of climate change and
46 Photo: Dave Wood Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust
rising sea temperatures. These include Styela clava, the Australasian barnacle, the purple topshell, Gibbula umbilicalis, Elminius modestus, the American razor, which was recorded for the first time in Ensis americanus, the American sand Kent in 2005, at St Margaret’s Bay. This gaper, Mya arenaria, the American had not been found previously, despite piddock, Petricola pholadiformis, and the dedicated surveys for this and other American sting winkle, Urosalpinx cinerea, climate change indicator species in Kent, have occurred in Kent for many years and Sabellaria spinulosa but it is now recorded in some abundance have possibly reached an equilibrium Ross worm on the chalk shores around Dover and position. However, they can frequently Thanet. Similarly, the small periwinkle, represent a significant component of Melarhaphe neritoides was found for the shore communities, sometimes first time at Ramsgate in 2006, and again dominating in the place of similar native in Folkestone in 2007, although this does species, such as the sword razor, Ensis not appear to have become widespread. ensis, the European sting winkle, The range of the grey triggerfish, Balistes Ocenebra erinacea, and the native acorn capriscus, a Mediterranean species, has barnacle, Semibalanus balanoides. been expanding along the south coast, Sargassum muticum was first recorded and records have now extended its growing in Kent in 1988, and is now known range to the Dover area. recorded forming blanketing growths in the tidal swimming pools and many The Cefas young fish survey revealed a rockpools around the Thanet coast. change in the make-up of young fish communities over the past 30 years, The Pacific oyster, Crassostrea gigas, was attributed to the corresponding increases introduced for commercial cultivation, in sea temperatures. The seas around believing the UK waters to be too cold to Kent feature a high proportion of the total allow it to breed. It has been present wild number of different species caught in this on the shores around Kent for several survey, being positioned on the edge of years, but has recently increased the warm Lusitanian waters from the significantly in dominance and extent, south west, and the cold waters from the following warm summer water North Sea. However, in the 1980s more temperatures, when breeding is triggered. cod were recorded, and in later years, A detailed study of their coverage more solonettes and rays were recorded. documents its increase around the Thanet Also now found in lower numbers are shores where it may impact on intertidal species such as eel pout, pogge and Sabellaria reefs and mussel beds butterfish, while species such as weaver (McKnight, 2009). There appear to be fish, black sea bream and tub gurnard some natural limiting factors to the appear to be on the increase in the area. species’ spread, such as storms which dislodge clusters from the chalk, and Non-native species smothering with fine sediment movement, There are several marine non-native as well as disease which has killed farmed species present around Kent, some of stock. which are well established, while some are relatively new arrivals and include invasive Another bivalve introduced to create a species which give cause for concern. fishery is the Manila carpet shell clam, Movement of vessels, ships’ ballast water Tapes philippinarum, which is now and the introduction of farmed oysters spreading along Kent’s shores. appear to have been the main vectors for the introduction of the county’s non-native The Chinese mitten crab, Eriocheir species. sinensis, occurs in several of the county’s freshwater bodies, where the animals Some species, such as wireweed, spend most of their lives before moving to Sargassum muticum, slipper limpets, marine waters to breed. The species has Crepidula fornicata, leathery seasquirt, also been recorded in several estuarine
47 Photo: Rachel Coppock Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust locations around the county, as well as Kent in 2011. This was found on the incidental capture by a fishing vessel off shore at Seasalter, whereas all previous Folkestone. The animals’ borrowing UK records were restricted to harbours, behaviour can cause considerable marinas and other man-made structures. damage to soft sediment banks, The species can quickly form gelatinous increasing erosion. sheets which smother native species, with resultant impact on biodiversity. The ongoing presence of a rare non-native Experimental eradication attempts in the Square Crab bamboo worm, Clymenella torquata, at confines of a Welsh harbour proved Goneplax Hythe Whitstable was confirmed in 2011. Its unsuccessful. Its rapid colonisation of Spoon Worm Site recorded distribution is restricted to intertidal boulders at Reculver within a Whitstable and very few other sites on the matter of weeks over the 2011 summer UK’s east coast. period is cause for great concern.
Other non-native algal species have been Still further invasive non-native species, recorded recently on the shores, but the such as the Japanese wakame kelp, occurrences of each have to date been Undaria pinnatifida, and the red alga, extremely limited. These include the Grateloupia turuturu, are currently believed green sea fingers alga, Codium fragile to be restricted to harbours around Kent, subsp. fragile, and the red alga, where the floating pontoons provide both Bonnemaisonia hamifera, both found in permanent sea water immersion and the man-made Walpole Bay swimming good light levels. Their further spread pool near Margate. Another new non- outwards to the shores has been native red alga, Asparagopsis armata was recorded elsewhere, and is possible found on the natural shore at Abbot’s Cliff around Kent. near Dover. A single location of a non- native hydroid, Cordylophora caspia, has The non-native red alga, Antithamnionella been recorded in Kent, in the Medway in spirographidis, has also been recorded in 2011; this species has not been reported both Dover and Ramsgate Harbours. The to compete with native species in the UK. non-native fan worm, Ficopomatus enigmaticus, occurs in Wellington Dock of A solitary seasquirt, Corella eumyota, was Dover Harbour. Its spawning requires first recorded in 2010 at Shakespeare variable salinity water, so that its Cliff. While only a few individuals have so distribution is largely restricted to harbours far been detected, this is highlighted as an and brackish waters. While it can invasive non-native species which can compete with native fauna for suspended form into large aggregations and smother food, it is noted to improve oxygen and native species. nutrient status in enclosed water bodies, to the benefit of other species. The very recent arrival of other highly invasive species could have severe Further survey to evaluate the spread of all implications for native species the invasive non-native species and their assemblages. impact on native biodiversity is required, although effective mechanisms for control The Pacific strain of a small red alga, have yet to be determined. Caulacanthus ustulatus was first recorded in Kent in 2009 around Dover. It has Pressures on marine habitats and rapidly spread around Dover and up to species Thanet where it dominates areas on the In addition to competition from non-native shore previously covered by native algal species, Kent’s seabed habitats and turf characterised by Gelidium pusillum. native marine biodiversity face a host of pressures from human activities in the A highly invasive colonial seasquirt, county’s extremely busy sea areas. Didemnum vexillum, was first recorded in Almost all the seabed around Kent is used
48 Photo: B Chapman
Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust
for commercial fishing of one type or against hard sea defences. another, for fin fish, crustaceans and molluscs, including dredging, trawling, Artificial structures have significantly potting, set netting, and shellfish farming. changed the nature and dynamics of the Fisheries impact on the populations of shoreline and some offshore areas, with target species, as well as unwanted the natural longshore drift of sediment bycatch species such as catsharks and being interrupted, and additional hard Undaria pin Wakame invertebrates. The habitat-forming attachment surfaces being available for Ramsgate mussel beds are commercially harvested, algae and sessile animals. and seed mussel is collected for growing on in other, more productive locations. Positive change Certain fishing gear types cause damage The Marine and Coastal Access Act to rock and sediment habitats and their 2009 presented a long-awaited associated assemblages of species, and opportunity to establish an ecologically to Sabellaria reef formations. Angling coherent network of Marine Protected removes certain targeted fish species, Areas (including new national-level and bait collection can disturb intertidal designations, Marine Conservation habitats while removing bait species. Zones), to formulate regional marine Significant levels of inter-tidal shellfish plans, and to create a Marine harvesting occur on the more accessible Management Organisation and ten chalk shores around Thanet by the public Inshore Fisheries and Conservation and organised groups. Authorities, responsible for planning and managing our seas sustainably. If Further habitat damage arises from the delivered robustly, these opportunities laying of cables and pipelines, from could help to reverse the degradation of commercial and recreational anchoring, marine biodiversity. and from the dredging and disposal of Ten Marine Conservation Zones (MCZs) sediment to open or maintain around Kent have been recommended navigational channels, or for extraction by the Balanced Seas’ Regional for construction. Coastal developments Stakeholder Group, for review by the and offshore developments, including the statutory nature conservation bodies and new offshore windfarms, can further the national MCZ Science Advisory change or reduce natural habitat Panel, before submission on to available for biodiversity. Government late in 2011. MCZ designations begin following public Considerable areas of saline wetland in consultation in 2012. Britain have been lost over the past two centuries, mostly due to drainage and References land claim, with concomitant loss of Howson, C., Bunker, F., and Mercer, T., higher plants and algal species. Aquatic Survey & Monitoring Ltd. 2005. Following significant land claim from the Isle of Thanet European Marine Site sea particularly in the Wantsum Channel sublittoral monitoring 2004. English and Romney Marsh areas, the Nature Contract FST20-46-16. saltmarshes of the Medway and Swale represent an important remaining JNCC Marine Recorder Database. resource in the county. Marine Ecological Surveys Limited. The seas also suffer from direct and 2008. Marine Macrofauna Genus Trait diffuse sources of pollution, from oil spills Handbook. Marine Ecological Surveys and sewage disposal to nutrient run off, Limited, 24a Monmouth Place, Bath, while climate change has severe BA1 2AY. 184pp. ISBN 978-0- implications through rising sea 9506920-2-9 temperatures, ocean acidification, and rising sea levels causing coastal squeeze McKnight, W., 2009. Pacific Oyster
49 Kent’s Marine Wildlife Bryony Chapman, Kent Wildlife Trust
survey of the North East Kent European marine sites. Natural England Spurrier, C., Tittley, I, and Chapman, B. Commissioned Report NECR016 2011. Biological survey of the intertidal chalk reefs between Folkestone Warren Natural England, 2010. Lost life: and Kingsdown, Kent. Kent Wildlife Trust England’s lost and threatened species report.
Natural England and JNCC 2010. Marine Tittley, I. and Price, J.H., 1977. An Atlas Conservation Zone Project. Ecological of the Seaweeds of Kent. Transactions of Network Guidance. the Kent Field Club Volume 7.
National Biodiversity Network Gateway. Tittley, I., Spurrier, C.J.H., Chimonides, www.nbn.org.uk/ P.J., Chapman, B. 2006 Thanet Coast Special Area of Conservation: 2005 Pain, C., Wilkinson, S. and Light, J. 2008. intertidal monitoring. English Nature Two further UK sites for Caecum Contract IIT25/05-06 armoricum, de Folin, 2869, formerly Tittley, I. 2008. Marine algae new to Kent. known only in the Fleet, Dorset, as a Bulletin of the Kent Field Club. member of the interstitial ‘springs’ community. Journal of Conchology, 2008, Tittley, I. In prep. Atlas of the Seaweeds VOL.39, NO.6 of Kent.
Plantlife, 2007. Important Plant Areas for UK Biodiversity Action Plan Priority Algae. A Provisional Review of Sites and Species. Areas of Importance for Algae in the UK. http://tna.europarchive.org/20110303145
With thanks to Mike Easterbrook, Ian Ferguson and David Gardner (Butterfly Conservation - Kent), Lee Brady (Kent Reptile and Amphibian Group), Andrew Henderson (Kent Ornithological Society), Shirley Thompson (Kent Bat Group), Richard Moyse and Bryony Chapman (Kent Wildlife Trust) and William Moreno (Kent Biodiversity Partnership/ Kent County Council)
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