Population distribution and conservation status of notable ...
Population distribution and conservation status of notable ...
Population distribution and conservation status of notable ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Special Interest report<br />
<strong>Population</strong> <strong>distribution</strong> <strong>and</strong> <strong>conservation</strong> <strong>status</strong> <strong>of</strong><br />
<strong>notable</strong> Whitebeam species on the Torbay coast.<br />
Tracey Hamston BSc., MSc.<br />
UK Conservation Officer WWCT<br />
1
CONTENTS Page<br />
Summary………………………………………………………...<br />
Objectives………………………………………………………..<br />
Biodiversity action plan…………………………………………<br />
Whitebeams in Devon………………………………………….<br />
History <strong>of</strong> whitebeams on the Torbay coastline……………..<br />
National <strong>distribution</strong> <strong>and</strong> <strong>status</strong>………………………………..<br />
Identification……………………………………………………..<br />
Figure 1. Leaf form <strong>of</strong> S. porrigentifomis <strong>and</strong> S. rupicola…..<br />
Figure 2. Hectad <strong>distribution</strong> map <strong>of</strong> Sorbus<br />
porrigentiformis………………………………………………….<br />
Figure 3. Hectad <strong>distribution</strong> map <strong>of</strong> Sorbus rupicola………<br />
Survey……………………………………………………………<br />
Distribution across the three sites…………………………….<br />
Conclusion……………………………………………………….<br />
Table 1. A comparison <strong>of</strong> population data <strong>of</strong> all sites for 1985<br />
<strong>and</strong> 2008 ………………………………………………….<br />
Figure 4. Babbacombe slopes………………………………...<br />
Figure 5. Redgate Cliffs………………………………………..<br />
Figure 6. Churston …………………………………………….<br />
Considerations <strong>and</strong> recommendations for monitoring………<br />
Site management recommendations…………………………<br />
References………………………………………………………<br />
Appendices (photographs & records)………………………..<br />
2<br />
3<br />
3<br />
4<br />
4<br />
5<br />
5<br />
6<br />
7<br />
8<br />
9<br />
9<br />
11<br />
12<br />
13<br />
14<br />
15<br />
16<br />
17<br />
18<br />
19<br />
1
SUMMARY<br />
This report describes the results <strong>of</strong> a survey carried out in 2008, with additional<br />
records from 2010, <strong>and</strong> makes management recommendations for the<br />
<strong>conservation</strong> <strong>of</strong> two species <strong>of</strong> Whitebeam; Sorbus rupicola Rock Whitebeam<br />
<strong>and</strong> Sorbus porrigentiformis Grey-leaved Whitebeam.<br />
It is intended that this report be used as a reference for identification <strong>and</strong> survey<br />
method.<br />
Whitebeams have been recorded on the Torbay coast for 180 years with the first<br />
specimens for both species collected in 1847 (Keble, Martin <strong>and</strong> Fraser; 1939).<br />
They now fall within the scope <strong>of</strong> the Local Biodiversity Action Plan.<br />
Both species are nationally scarce <strong>and</strong> Grey-leaved Whitebeam is endemic to<br />
Britain where it is restricted to the south west. They both exist as small isolated<br />
populations with low total numbers restricted to areas <strong>of</strong> base-rich rock, <strong>of</strong>ten<br />
limestones or basalts <strong>and</strong> are found growing on cliffs <strong>and</strong> steep rocky slopes,<br />
typically in well lit situations.<br />
This study compares data with a survey carried out in 1985 with the aim <strong>of</strong><br />
assessing any changes in population size during this time. Both surveys were<br />
carried out at three sites on the Torbay coastline; Babbacombe slopes NGR SX<br />
926 656; Redgate cliff NGR SX 934 647; Churston Cove NGR SX 917 570.<br />
A potentially catastrophic decline in population size <strong>of</strong> 76% has occurred since<br />
1985 at Babbacombe. The other sites show smaller losses but little or no<br />
evidence <strong>of</strong> natural regeneration. Evidence suggests that woodl<strong>and</strong> closure may<br />
be an important factor in the decline <strong>of</strong> these whitebeam populations<br />
It is recommended that scrub management <strong>and</strong> thinning around individual trees<br />
should be undertaken as soon as possible to safeguard these populations which<br />
are in danger <strong>of</strong> being overwhelmed by aggressive native <strong>and</strong> non-native tree<br />
species.<br />
It is also recommended that consideration should be given to extend available<br />
habitat for natural regeneration.<br />
Future monitoring <strong>of</strong> these populations is essential to assess the effectiveness <strong>of</strong><br />
any management.<br />
2
OBJECTIVES<br />
This report is a summary <strong>of</strong> a study carried out for a masters degree <strong>and</strong> aims to<br />
1. Establish the <strong>status</strong> <strong>of</strong> the *apomictic Whitebeam species, Sorbus<br />
porrigentiformis (Grey-leaved Whitebeam) <strong>and</strong> Sorbus rupicola (Rock<br />
Whitebeam) within Torbay. (* see page 4)<br />
2. Identify management that will ensure the future survival <strong>and</strong> expansion <strong>of</strong><br />
these species on the Torbay sites; Babbacombe slopes; Redgate & Walls<br />
Hill; Churston.<br />
3. Establish monitoring protocol for the future monitoring <strong>of</strong> these<br />
populations.<br />
BIODIVERSITY ACTION PLAN<br />
This report addresses some <strong>of</strong> the objectives contained within the Local<br />
biodiversity Action Plan.<br />
The Biodiversity objectives for Whitebeam in Devon as defined by the Devon<br />
BAP are<br />
1. Maintain current viable populations <strong>of</strong> the apomictic species <strong>of</strong> whitebeam<br />
in Devon.<br />
2. Attain a better underst<strong>and</strong>ing <strong>of</strong> the <strong>distribution</strong> <strong>and</strong> size <strong>of</strong> population <strong>of</strong><br />
whitebeam species in Devon.<br />
3. Increase awareness <strong>and</strong> underst<strong>and</strong>ing <strong>of</strong> the Devon whitebeam species<br />
among l<strong>and</strong> owners/managers, <strong>conservation</strong>ists <strong>and</strong> the general public.<br />
It also meets most <strong>of</strong> the Priority or Indicative Actions listed in the BAP that are<br />
relevant to Sorbus porrigentiformis <strong>and</strong> S. rupicola on the Torbay coastline.<br />
These actions are:<br />
1. Encourage appropriate management <strong>of</strong> sites containing whitebeams;<br />
controlling excessive scrub <strong>and</strong> invasive species such as rhododendron,<br />
<strong>and</strong> regulating any grazing so as to allow natural regeneration.<br />
2. Ensure local authorities are informed <strong>of</strong> endemic Whitebeam locations <strong>and</strong><br />
that they take proper account <strong>of</strong> the effects <strong>of</strong> proposed developments on<br />
populations. To include Tree Preservation Orders to protect individual<br />
Whitebeam trees.<br />
3. Offer l<strong>and</strong>owners <strong>and</strong> managers <strong>of</strong> all sites that hold the apomictic species<br />
<strong>of</strong> whitebeam advice on the location <strong>of</strong> trees, their scientific importance<br />
<strong>and</strong> vulnerability <strong>and</strong> good management practice.<br />
4. Re-survey all known sites <strong>of</strong> apomictic species once every 10 years.<br />
Ensure records are sent to Devon Biodiversity Record Centre (DBRC) <strong>and</strong><br />
Botanical Society British Isles (BSBI) county recorder.<br />
3
The survey sites fall within the scope <strong>of</strong> the Torbay Local Biodiversity Action Plan<br />
‘The Nature <strong>of</strong> Torbay’.<br />
Sorbus porrigentiformis <strong>and</strong> S. rupicola are listed as c<strong>and</strong>idate species<br />
highlighted in the plan for Maritime cliff <strong>and</strong> slope. They form part <strong>of</strong> the<br />
characteristic calcareous flora <strong>of</strong> this habitat.<br />
The relevant actions listed are<br />
• Maintain population <strong>of</strong> Sorbus porrigentiformis <strong>and</strong> S. rupicola.<br />
• Identify <strong>and</strong> map population <strong>of</strong> Whitebeam Sorbus porrigentiformis <strong>and</strong> S.<br />
rupicola.<br />
WHITEBEAMS IN DEVON<br />
Whitebeams are attractive trees, so called for the characteristic white backs to<br />
the leaves. They produce clusters <strong>of</strong> red or orange fruit in the autumn. They<br />
belong to the genus Sorbus which comprises approximately 40 species in Britain.<br />
The British species <strong>of</strong> Sorbus comprise three widespread <strong>and</strong> sexually<br />
reproducing trees; rowan S. aucuparia, common whitebeam S. aria <strong>and</strong> wild<br />
service tree S.torminalis. In addition to these there are a number <strong>of</strong> species that<br />
are mostly ‘apomictic’ i.e. they produce seed without sexual reproduction. They<br />
still require pollination for seed set to occur but effectively give rise to clonal lines<br />
where the progeny have the same genetic constitution as their parents.<br />
Devon has eight such species <strong>and</strong> is one <strong>of</strong> the richest counties in Britain for<br />
whitebeam. The whitebeams <strong>of</strong> Devon are <strong>of</strong> interest to biologists <strong>and</strong><br />
geneticists as they provide evidence <strong>of</strong> a continuing evolutionary process which<br />
gives rise to new species. Sorbus porrigentiformis <strong>and</strong> S. rupicola are both<br />
known to be integral to this process, occasionally hybridising with other Sorbus<br />
species <strong>and</strong> possibly each other.<br />
HISTORY OF WHITEBEAMS ON THE TORBAY COASTLINE<br />
Earliest records <strong>of</strong> Torbay Whitebeams were made as Pyrus aria <strong>and</strong> may well<br />
have been either S. porrigentiformis or S. rupicola since neither was recognised<br />
at the time. In Flora Devoniensis (Jones <strong>and</strong> Kingston, 1829) the entry ‘Pyrus<br />
aria …a small tree.. .’ found on rocks at Babbacombe <strong>and</strong> near Torquay’ may<br />
well have referred to either S. porrigentiformis or S. rupicola both <strong>of</strong> which are<br />
still found in this location. The H<strong>and</strong>book <strong>of</strong> the Torquay Flora (Stewart, 1860,<br />
p.44) states ‘there are several varieties <strong>of</strong> this shrub (Pyrus aria). Park Hill,<br />
Torquay’. S. porrigentiformis is still found in this locality so it is likely that these<br />
‘varieties’ include this species. The earliest confirmed Torbay specimens for both<br />
4
species were collected in Torquay by Rev. C. E. Parker in 1847 <strong>and</strong> were held in<br />
the Torquay Natural History Society herbarium. They were included in accounts<br />
for V.C. 3 in Flora <strong>of</strong> Devon (Keble, Martin <strong>and</strong> Fraser; 1939). S. porrigentiformis<br />
was referred to at this time as Sorbus porrigens Hedl. ‘Devon form’.<br />
The Torbay Wildlife Survey (Lock, 1991) noted the presence <strong>of</strong> both species at<br />
the sites visited during this survey, but lacked detail on population sizes.<br />
Margaret Bradshaw carried out a detailed survey in 1984-5 funded by the Nature<br />
Conservancy Council, but, despite their scarcity, there has been no recent survey<br />
to determine the current <strong>status</strong> <strong>of</strong> these two species.<br />
NATIONAL DISTRIBUTION AND STATUS<br />
Sorbus rupicola <strong>and</strong> Sorbus porrigentiformis are both nationally scarce species<br />
(Stewart et al. 1994). The New Atlas <strong>of</strong> the British Flora (Preston, et al., 2002)<br />
shows occurrences in 59 <strong>and</strong> 26 ten kilometre squares for S. rupicola <strong>and</strong> S.<br />
porrigentiformis respectively, recorded between the years <strong>of</strong> 1987 <strong>and</strong> 1999.<br />
S. porrigentiformis is endemic to Britain, i.e. it only occurs in Britain. It is<br />
restricted largely to the south-west <strong>of</strong> Engl<strong>and</strong> <strong>and</strong> south Wales. S. rupicola is<br />
more widespread, being endemic to north-west Europe.<br />
Both species are restricted to areas <strong>of</strong> base-rich rock, <strong>of</strong>ten limestones or basalts<br />
<strong>and</strong> are found growing on cliffs <strong>and</strong> steep rocky slopes, typically in well lit<br />
situations. They exist as small populations, sometimes only single trees, which<br />
makes them extremely vulnerable to local extinction.<br />
Torbay has the most southerly populations in the U.K.<br />
IDENTIFICATION<br />
The trees are identified by the broadest leaves <strong>of</strong> the short lateral rosettes<br />
growing in sunlit conditions. The st<strong>and</strong>ard method for Sorbus identification<br />
follows Aas et al., (1994, cited in Rich, 2005). The most typical leaves are those<br />
fully exp<strong>and</strong>ed excluding the oldest <strong>and</strong> youngest ones. Saplings <strong>and</strong> young<br />
shoots growing from cut back stems have atypical juvenile leaves which cannot<br />
be used for identification. The best time to search for individual trees is on windy<br />
days when the white backs <strong>of</strong> the leaves are more clearly visible <strong>and</strong> during<br />
fruiting in September –October.<br />
S. rupicola <strong>and</strong> S. porrigentiformis can be differentiated by their leaf shape.<br />
Sorbus rupicola also tends to be larger, occurring as a shrub or tree up to 10 m<br />
tall compared to Sorbus porrigentiformis which tends to be a shrub or more rarely<br />
a small tree up to 5-10m tall. The leaves <strong>of</strong> S. rupicola differ from Sorbus<br />
porrigentiformis in that they are longer relative to their width. The leaves <strong>of</strong> both<br />
are white tormentose beneath. Ripe fruits are deep red (12-15mm) with<br />
numerous lenticels scattered over the surface. Flowering occurs earlier in S.<br />
porrigentiformis from May to June <strong>and</strong> from June to early July for S. rupicola.<br />
Fruiting is from September to November.<br />
5
Sorbus rupicola<br />
Sorbus porrigentiformis<br />
Figure 1. Leaf form <strong>of</strong> S. porrigentifomis <strong>and</strong> S. rupicola. From Plant Crib<br />
(Rich & Jermy, 1998)<br />
6
Sorbus porrigentiformis<br />
Figure 2. Hectad <strong>distribution</strong> map <strong>of</strong> Sorbus porrigentiformis (Greyleaved<br />
Whitebeam) in Britain <strong>and</strong> Irel<strong>and</strong>. Map supplied by T.C.G. Rich,<br />
2009. The red circle highlights the Torbay records.<br />
7
Sorbus rupicola<br />
Figure 3 . Hectad <strong>distribution</strong> map <strong>of</strong> Sorbus rupicola (Rock Whitebeam)<br />
in Britain <strong>and</strong> Irel<strong>and</strong>. Map supplied by T.C.G. Rich, 2009. The red circle<br />
highlights the Torbay records.<br />
8
SURVEY<br />
Despite their scarcity there has been no recent survey to establish <strong>status</strong> <strong>and</strong><br />
population size <strong>of</strong> S. rupicola <strong>and</strong> S. porrigentiformis within Torbay. Given the<br />
uncertainty <strong>of</strong> these population sizes <strong>and</strong> the potential effects <strong>of</strong> planned site<br />
management, it is important that a monitoring programme is established to<br />
ensure maintenance <strong>of</strong> these populations. No seedlings were recorded or<br />
observed by Bradshaw in 1984/5 <strong>and</strong> there is concern that the populations are<br />
not successfully recruiting. Historic Ordnance Survey maps <strong>and</strong> photographs <strong>of</strong><br />
the two predominantly wooded sites, Babbacombe <strong>and</strong> Churston, from late<br />
1800’s to the 1930’s, show them to have been open grassl<strong>and</strong> with scrub with<br />
occasional small trees scattered across the slopes.<br />
Sites<br />
The areas surveyed were<br />
1. Babbacombe slopes SSSI – an area between Babbacombe downs <strong>and</strong><br />
the coast. (Fig. 3). NGR SX 926 656<br />
2. Redgate Cliffs SSSI – from Redgate beach up the cliff face between<br />
Ansteys cove <strong>and</strong> Walls Hill. (Fig. 4). NGR SX 934 647<br />
3. Churston Cove CWS – an area stretching from fishcombe point across to<br />
the battery gardens. (Fig.5). NGR SX 917 570<br />
Note: Wall’s Hill was surveyed in 2010, see Appendices photographs pg 20.<br />
The 2008 survey repeated that <strong>of</strong> Margaret Bradshaw in 1984-5 in order to detect<br />
any changes in population size during the last 23 years. All records have been<br />
lodged with the county recorder for vascular plants, R.E. N. Smith.<br />
All trees had their location recorded with a 10 figure GPS (Global Positioning<br />
System) coordinate with the accuracy <strong>of</strong> the GPS unit noted. The locations <strong>of</strong> the<br />
trees were also described <strong>and</strong> mapped on large scale site maps. (Figures 3-5).<br />
The larger trees were tagged using aluminium tree tags which carry a unique<br />
identifying number <strong>and</strong> the canopy density was measured.<br />
Using tree ring data from stems found already broken it was possible to estimate<br />
the stem ages <strong>of</strong> other trees <strong>and</strong> thus calculate recruitment since 1985.<br />
DISTRIBUTION ACROSS THE SITES<br />
Between them, the three study sites support or have supported 100% <strong>of</strong> all S.<br />
rupicola ever recorded in Torbay <strong>and</strong> 80 – 90% <strong>of</strong> S. porrigentiformis.<br />
Habitats present<br />
All the sites have steep coastal slopes, cliffs <strong>and</strong> quarried areas. Babbacombe<br />
<strong>and</strong> Redgate have areas <strong>of</strong> loose rock. Babbacombe is dominated by high<br />
canopy Ash Fraxinus excelsior <strong>and</strong> Sycamore Acer pseudoplatanus <strong>and</strong> there is<br />
little open habitat. Churston also has large areas <strong>of</strong> similar woodl<strong>and</strong> but also<br />
9
scrub <strong>and</strong> species rich calcareous grassl<strong>and</strong> on the headl<strong>and</strong>s <strong>and</strong> the quarries.<br />
The Sorbus at Redgate are found on the open, rocky slopes. The more stable<br />
areas support species rich calcareous grassl<strong>and</strong> but Cotoneaster, Holm Oak<br />
Quercus ilex <strong>and</strong> Butterfly Bush Buddleia davidii have invaded in places. Ash has<br />
also spread into previously open areas.<br />
S. porrigentiformis was recorded at Redgate <strong>and</strong> Babbacombe with one tree<br />
recorded at Walls Hill, a headl<strong>and</strong> adjacent to Redgate beach <strong>and</strong> approximately<br />
0.8km from the Babbacombe site. It is known that more trees exist on the less<br />
accessible parts <strong>of</strong> the open cliff at Redgate <strong>and</strong> Walls Hill. These areas will be<br />
the subject <strong>of</strong> a future survey.<br />
<strong>Population</strong> size<br />
85% <strong>of</strong> S. porrigentiformis trees recorded in 2008 are associated with the open<br />
rocky slopes at Redgate, with only 2 trees on the wooded slopes at<br />
Babbacombe. All <strong>of</strong> the trees grow on rock outcrops or cliffs, open scree slopes<br />
<strong>and</strong> the edges <strong>of</strong> quarried areas. No S. porrigentiformis was recorded on the<br />
shallower slopes where the soils are presumably deeper.<br />
S. rupicola was recorded at both Babbacombe <strong>and</strong> Churston with 78% <strong>of</strong> trees<br />
found at the Churston site. Again, the trees are almost exclusively associated<br />
with changes in slope at the edge <strong>of</strong> quarried areas, rocky slopes or cliff tops with<br />
few exceptions. Only 4 <strong>of</strong> the 21 S. rupicola were found in open conditions.<br />
Both species were confined to areas known historically to have been open with<br />
grassl<strong>and</strong> or scrub vegetation.<br />
Babbacombe<br />
This site showed the largest difference in tree numbers recorded between<br />
surveys. Of the 19 trees recorded in 1984-5, only 16% (3 trees) were re-found in<br />
2008. Using the growth ring data to cross reference, it is likely that all the current<br />
trees are old enough to have been present in 1985. None <strong>of</strong> the trees recorded in<br />
2008 are less than 10 years old <strong>and</strong> it seems probable that no recruitment has<br />
taken place since 1985.<br />
16 trees have been lost, the majority <strong>of</strong> these (12 <strong>of</strong> the 16 trees) were S.<br />
porrigentiformis <strong>and</strong> 6 <strong>of</strong> these were recorded as small bushes or spindly trees<br />
by Bradshaw, 1985.<br />
Redgate & Wall’s Hill<br />
This site is not fully accessible without climbing equipment <strong>and</strong> areas <strong>of</strong> loose<br />
rock would make climbing hazardous in places. Binoculars were therefore used<br />
to scan thse parts <strong>of</strong> the cliffs. This site had the highest proportion <strong>of</strong> fruiting<br />
trees <strong>and</strong> 36% (5 trees) <strong>of</strong> those recorded in 1985 are thought to be lost. The<br />
lost trees were all in an area now covered with dense Cotoneaster, Blackthorn<br />
10
Prunus spinosa <strong>and</strong> Holm oak Quercus ilex. 22 trees were recorded in 2008. Of<br />
these, 4 were small plants, which have probably appeared since 1985.<br />
Wall’s Hill was surveyed using binoculars <strong>and</strong> a telescope during 2010. 7 trees<br />
/bushes were located <strong>and</strong> it’s likely there are more but rope access would be<br />
needed to ascertain their exact location. See Appendices photographs pg 20.<br />
Churston<br />
This site was mostly accessible with only relatively small areas <strong>of</strong> dense scrub.<br />
At least 1 tree has been lost since 1985. Note that during recent scrub clearance<br />
(2009) a further tree was cut down <strong>and</strong> appeared to have been stump treated.<br />
Effect <strong>of</strong> canopy cover<br />
Canopy cover had an inverse relationship with fruiting levels. Cover from<br />
competing trees prevented flower formation <strong>and</strong> thus fruit production.<br />
Reproduction in these whitebeam species is dependant upon seed production as<br />
they do not sucker. Increasing competition for light from more vigorous tree<br />
species such as Ash Fraxinus excelsior <strong>and</strong> Sycamore Acer platinoides has<br />
doubtless restricted recruitment <strong>and</strong> thus led to the decline <strong>of</strong> whitebeams on the<br />
more wooded sites. These species are intolerant <strong>of</strong> shade, with small or young<br />
trees unable to reach the canopy. Many <strong>of</strong> those trees that have disappeared<br />
were described as small trees or bushes. This seems particularly so for Sorbus<br />
porrigentiformis, which tends to be smaller than S. rupicola.<br />
CONCLUSION<br />
Churston <strong>and</strong> the Redgate-Wall’s Hill area appear to support populations<br />
that are stable at present. There is concern that S. rupicola at Churston is<br />
not regenerating <strong>and</strong> the open habitat there is restricted.<br />
It is clear that the greatest loss is Sorbus porrigentiformis on the<br />
Babbacombe site, (Table 1). This site is important because it supports both<br />
species <strong>and</strong> if we are to develop <strong>conservation</strong> policies that protect the<br />
evolutionary potential <strong>of</strong> Whitebeams then these types <strong>of</strong> sites will be a<br />
priority.<br />
Reductions across the sites can be attributed to mortality (24 trees). Of<br />
those thought to have died, the likely causes are l<strong>and</strong> slips (recorded for 2<br />
trees), woodl<strong>and</strong> canopy closure (a possible 19 trees) <strong>and</strong> increasing<br />
competition for resources from invasive non-native species, notably Holm<br />
oak <strong>and</strong> Cotoneaster spp. (a possible 5 trees).<br />
These represent the main threats to Whitebeams across these sites.<br />
11
Table 1. A comparison <strong>of</strong> population data <strong>of</strong> all sites for 1985 <strong>and</strong> 2008.<br />
* This represents the trees found in 1985 plus those found in 2008 <strong>of</strong> sufficient size to have been present in 1985.<br />
SITE Species 1985<br />
Trees<br />
recorded<br />
*1985<br />
Total<br />
1985 - 2008<br />
Recruitment<br />
2008<br />
/2010<br />
Total<br />
1985 – 2008<br />
Trees lost<br />
as % <strong>of</strong><br />
1985 total<br />
Churston S. rupicola 19 25 3 23 5 (20%)<br />
Babbacombe S. rupicola 5 9 0 6 3 (33%)<br />
Babbacombe S. porrigentiformis 14 15 0 2 13 (87%)<br />
Redgate S. porrigentiformis 14 23 4 22 5 (21%)<br />
TOTAL 52 72 7 53 26 (36%)<br />
12
.B1<br />
.B8<br />
Figure 4. Babbacombe slopes. Sorbus spp.<br />
marked in red .<br />
.B2<br />
.B6<br />
.B7<br />
.B4<br />
.B3 .B5<br />
N<br />
13
.R1<br />
.R3<br />
.R4<br />
(R20, R21 & R22 ). .R13<br />
R11.<br />
R10. R6. .R5 .R9<br />
.R15 .R7& 8<br />
.R14 .R2<br />
.R23<br />
.R24<br />
R18 & 19 ..<br />
.R16<br />
.R17<br />
N<br />
Closed path up to<br />
Wall’s Hill<br />
Figure 5. Redgate Cliffs. Sorbus porrigentiformis marked in red .<br />
14
.C19<br />
.C16<br />
C21. .C20<br />
.C17<br />
The Grove<br />
.C9<br />
.C8<br />
.C12<br />
.C11<br />
.C10<br />
.C14<br />
.C15<br />
.C13<br />
.C7 .C6<br />
.C5<br />
.C23<br />
.C24<br />
Figure 6. Churston. Sorbus rupicola marked in red .<br />
.C4<br />
Churston Cove<br />
Fishcombe point<br />
.C3<br />
Fishcombe Cove<br />
15<br />
.C22<br />
.C2<br />
.C1
CONSIDERATIONS AND RECOMMENDATIONS FOR MONITORING<br />
ACCESS<br />
Many Sorbus species are found on inaccessible cliffs <strong>and</strong> rocky slopes, making<br />
survey work potentially hazardous, or at least difficult to complete in a systematic<br />
fashion. The development <strong>of</strong> monitoring programmes on many Sorbus sites need<br />
to take this into consideration.<br />
• If specimens are required for identification purposes, use long h<strong>and</strong>led<br />
pole loppers to reach sunlit leaves.<br />
• Binoculars <strong>and</strong> / or a telescope may be used to scan open areas <strong>of</strong> cliff<br />
where identification between species is not an issue.<br />
SURVEYORS<br />
It is known that recorders are a source <strong>of</strong> survey error, with variation between<br />
recorders <strong>and</strong> even the same individual recording on different days.<br />
• Consistency <strong>of</strong> recording is best achieved using the same person to carry<br />
out monitoring. Someone familiar with the site such as the site manager is<br />
best placed to keep such records. This also maintains a connection<br />
between site management <strong>and</strong> monitoring.<br />
• Surveying at the same time <strong>of</strong> year <strong>and</strong> using the same method promotes<br />
consistency.<br />
GPS COORDINATES<br />
It should be noted that GPS coordinates <strong>of</strong> more than 6 figure resolution are<br />
subject to errors beyond the detection <strong>of</strong> h<strong>and</strong> held GPS units. They should not<br />
be relied upon to identify individual trees. However, they are a useful tool to find<br />
trees in conjunction with a map <strong>and</strong> site description.<br />
TIMING OF SURVEY<br />
When to survey <strong>and</strong> how <strong>of</strong>ten?<br />
Problems encountered in other studies were changes in visibility, due to annual<br />
variation in fruiting <strong>and</strong> timing <strong>of</strong> autumn leaf colour. The visibility <strong>of</strong> the trees<br />
varied with weather conditions. This was most noticeable on windy days when<br />
the white backs <strong>of</strong> the leaves were most visible. The trees were also easier to<br />
find on the more open rocky slopes than in the woodl<strong>and</strong>.<br />
When to survey.<br />
16
• Fruiting trees are prominent from September – October, however this<br />
study showed that many trees don’t fruit <strong>and</strong> fruiting fluctuates annually.<br />
• Where only one species is known to occur so there is not an identification<br />
issue, shortly after bud burst in May the trees are visible due to the<br />
prominent white backs on the new foliage.<br />
• Where both species are present, mature, fully exp<strong>and</strong>ed leaves are<br />
required for identification. In this instance surveys must take place from<br />
June onwards.<br />
How <strong>of</strong>ten<br />
Due to the large decline in the Torbay whitebeam populations over the last 20<br />
years it is recommended that they be resurveyed every 5 years. This is<br />
particularly important where site management has changed. <strong>Population</strong>s that are<br />
stable may be resurveyed every 10 years.<br />
SITE MANAGEMENT RECOMMENDATIONS<br />
To ensure their survival for the future it is vital that these whitebeams are able to<br />
reproduce <strong>and</strong> that seedlings can survive to maturity.<br />
Fruit & flower promotion<br />
It is recommended that halo thinning is carried out around mature trees to allow<br />
light to promote flowering <strong>and</strong> fruiting. As whitebeams are very slow growing,<br />
mature trees may small. Anything with a girth circumference <strong>of</strong> more than 10cm<br />
should be considered capable <strong>of</strong> flowering.<br />
To allow good light penetration, clearings should be twice the canopy height<br />
across.<br />
Recruitment<br />
Strong consideration should be given to creating recruitment opportunities. Areas<br />
around existing trees, particularly where they occur in groups, should be cleared<br />
<strong>of</strong> scrub <strong>and</strong> the resulting soil disturbance will encourage seed germination.<br />
Invasive alien species<br />
Cotoneaster spp., Holm oak Quercus ilex <strong>and</strong> Butterfly bush Buddleia davidii are<br />
all targets <strong>of</strong> current clearance work that will benefit whitebeams. Care should be<br />
taken that whitebeams are not cut down during this work. They should be marked<br />
beforeh<strong>and</strong> to prevent confusion by contractors.<br />
17
Grazing<br />
Long term scrub control may include introduction <strong>of</strong> grazing animals. Browsing by<br />
such animals is a serious threat on some sites where <strong>conservation</strong> grazing <strong>of</strong><br />
grassl<strong>and</strong> habitat has lead to loss <strong>of</strong> rare whitebeams. Whitebeams should be<br />
fenced <strong>of</strong>f to prevent this. As grazing is likely to be restricted on these sites the<br />
conflict would be limited to small areas.<br />
REFERENCES<br />
Bishop, H. <strong>and</strong> Fisher, J. (2005) Babbacombe Downs Conservation Area<br />
Character Appraisal. Report for Torbay Council.<br />
Keble, Martin, W. <strong>and</strong> Fraser, G. T. (eds.) (1939) Flora <strong>of</strong> Devon. Arbroath.<br />
Pp.319-320<br />
Lock, L. (1991) Torbay Wildlife Survey. An unpublished report held by Devon<br />
Biodiversity Records Centre.<br />
Preston, C.D., Pearman, D.A. & Dines, T.D. (eds), (2002) New Atlas <strong>of</strong> the<br />
British <strong>and</strong> Irish Flora. Oxford:Oxford University Press.<br />
Proctor, M. E. & Proctor, M. C. F. (1990). Whitebeams in the Torbay area.<br />
Transactions & Proceedings, Torquay Natural History Society 20: 131-140.<br />
Rich, T. C. G., Motley, G. S. <strong>and</strong> Kay, Q. O. N. (2005). <strong>Population</strong> sizes <strong>of</strong> three<br />
rare Welsh endemic Sorbus species (Rosaceae). Watsonia 25: 381-388<br />
Rich, T.C.G. & Jermy, A.C. (1998). Plant Crib 1998. , London: Botanical Society<br />
<strong>of</strong> the British Isles.<br />
Stewart, A., Pearman, D.A. <strong>and</strong> Preston, C.D. (1994). Scarce Plants in Britain.<br />
Peterborough: JNCC.<br />
18
Appendix 1. Wall’s Hill. From flagstaff Point<br />
View down west side <strong>of</strong> Flagstaff Point<br />
Below cliff<br />
19
West from Flagstaff Point<br />
Indicate approximate positions <strong>of</strong><br />
individual S. porrigentiformis<br />
Several in this area amongst gorse,<br />
cotoneaster, ash & sycamore<br />
At least one tree<br />
on cliff edge<br />
20
Appendix 2. Records for all sites<br />
No. Tag Sorbus Site GPS GPS<br />
ref. no. Species eastings northings<br />
B1 940 S. rupicola<br />
B3 938 S. rupicola<br />
B4 937 S. rupicola<br />
B5 936 S. rupicola<br />
B6 \ S. rupicola<br />
B7 935 S. rupicola<br />
GP<br />
S Date Comments<br />
error<br />
± m<br />
Babbacombe<br />
cliffs 92650 65634 4<br />
Babbacombe<br />
cliffs 92717 65591 4<br />
Babbacombe<br />
cliffs 92725 65596 4<br />
Babbacombe<br />
cliffs 92730 65584 5<br />
Babbacombe<br />
cliffs 92727 65595 5<br />
Babbacombe<br />
cliffs 92737 65600 6<br />
C1 848 S. rupicola Fishcombe 92006 56857 6<br />
C2 \ S. rupicola Fishcombe 92005 56913 5<br />
C3 \ S. rupicola Fishcombe 91893 56922 3<br />
C4 829 S. rupicola<br />
C5 828 S. rupicola<br />
Grove,<br />
Churston 91789 56824 4<br />
Grove,<br />
Churston 91773 56956 7<br />
12<br />
September<br />
2008<br />
12<br />
September<br />
2008<br />
12<br />
September<br />
1 Leader splits into 2 @ 0.5m plus v small sucker.Tree<br />
on bend <strong>of</strong> road, v prominent <strong>and</strong> can be seen from<br />
telescope point on Babbacombe Downs. Tree in<br />
canopy layer.<br />
Leaning out into canopy downhill. E <strong>of</strong> B2, visible<br />
from path above.<br />
2008 Directly below B3 down slope.<br />
12<br />
September<br />
2008<br />
12<br />
September<br />
2008<br />
12<br />
September<br />
2008<br />
02<br />
September<br />
On v steep slope, stem running along ground. 6m E <strong>of</strong><br />
B4<br />
On woodl<strong>and</strong> edge at top <strong>of</strong> loose rocks above bottom<br />
path. Several stems travelling along ground (appears<br />
to be more than 1 tree) from same origin. NW <strong>of</strong> B7<br />
along woodl<strong>and</strong> edge, amongst bracken.<br />
On woodl<strong>and</strong> edge at top <strong>of</strong> loose rocks above bottom<br />
path. Several stems travelling along ground (appears<br />
to be more than 1 tree) from same origin.<br />
2008 Tag at 2m. Large tree in dense Ash/ Sycamore.<br />
02<br />
September<br />
2008<br />
03 October<br />
2008<br />
06<br />
September<br />
2008<br />
06<br />
September<br />
2008<br />
SW <strong>of</strong> steps on path from battery gardens to e side<br />
fishcombe cove.<br />
Large tree on edge <strong>of</strong> cliff between fishcombe cove<br />
<strong>and</strong> Churston cove. Easily seen from beach at low<br />
tide.<br />
Upright tree. Approx 7m w <strong>of</strong> main path. 40m W <strong>of</strong><br />
holiday camp. In high canopy -partly shaded by<br />
Sycamore<br />
Tree growing from edge <strong>of</strong> small level area. Small<br />
suckers present. A leader has been recently broken<br />
<strong>of</strong>f, sample taken for ring count (13.1cm circ with 27<br />
rings).<br />
21
C6 \ S. rupicola<br />
C7 827 S. rupicola<br />
C8 830 S. rupicola<br />
C9 850 S. rupicola<br />
C10 923 S. rupicola<br />
C11 924 S. rupicola<br />
C12 925 S. rupicola<br />
C13 \ S. rupicola<br />
C14 930 S. rupicola<br />
C15 \ S. rupicola<br />
C16 \ S. rupicola<br />
C17 934 S. rupicola<br />
C19 933 S. rupicola<br />
Grove,<br />
Churston 91774 56965 7<br />
Grove,<br />
Churston 91760 56975 11<br />
Grove,<br />
Churston 91732 57022 5<br />
Grove,<br />
Churston 91738 57027 5<br />
Grove,<br />
Churston 91741 56934 8<br />
Grove,<br />
Churston 91728 56945 8<br />
Grove,<br />
Churston 91718 56948 5<br />
Fishcombe<br />
point,<br />
Churston 91766 57048 3<br />
Fishcombe<br />
point,<br />
Churston 91770 57081 6<br />
Fishcombe<br />
point,<br />
Churston 91762 57072 4<br />
Fishcombe<br />
point,<br />
Churston 91636 57057 3<br />
Fishcombe<br />
point,<br />
Churston 91651 57070 3<br />
Grove,<br />
Churston 91608 57000 4<br />
06<br />
September<br />
2008<br />
06<br />
September<br />
2008<br />
06<br />
September<br />
2008<br />
06<br />
September<br />
2008<br />
07<br />
September<br />
2008<br />
07<br />
September<br />
2008<br />
07<br />
September<br />
2008<br />
07<br />
September<br />
2008<br />
07<br />
September<br />
2008<br />
07<br />
September<br />
2008<br />
13<br />
September<br />
2008<br />
13<br />
September<br />
2008<br />
13<br />
September<br />
2008<br />
Young tree growing along ground then leaning down<br />
slope. N <strong>of</strong> 5.<br />
Large tree with 4 leaders branching from low down<br />
(0.5m) Up slope over looking beach.<br />
(Proctor ref. 18 - note comments <strong>of</strong> open rocky slope)<br />
Slender tree SW <strong>of</strong> coast path. N <strong>of</strong> beach on steep<br />
slope. In scrub.<br />
NE <strong>of</strong> 8. Crown can be seen from rocks on S side <strong>of</strong><br />
beach. Inaccessible in thorn scrub.<br />
Old stool, multi stemmed. Edge <strong>of</strong> small quarried area<br />
/ cliff 3m high. SW <strong>of</strong> 7.<br />
old stool with large leaders. Tree in canopy, partly<br />
shaded. Healthy<br />
Stool on cliff edge (2-3m high) leaning downhill to<br />
light. Tree in canopy, partly shaded<br />
Coppiced shrub with many small shoots, most with<br />
juvenile leaves. Remains <strong>of</strong> larger stump previously<br />
cut back to ground level - approx 20cm circumference.<br />
NW <strong>of</strong> steps down to beach, approx 6m from railing<br />
N side <strong>of</strong> point, inaccessible due to steepness <strong>of</strong> cliff /<br />
slope. Looking down on crown, many fruit, canopy in<br />
open amongst stunted Ash <strong>and</strong> scrub. NGR taken<br />
from nearest point approx 8m away on top <strong>of</strong> ridge.<br />
Small sapling with single stem. Close to 14. NGR<br />
taken from nearest point on ridge.<br />
Small tree under oak with low canopy. Main leader<br />
found broken <strong>of</strong>f on later visit (3.10.2008) - sample<br />
taken for ring count at above ground level - (10.8cm<br />
circ with 24 rings)<br />
Huge tree sloping back up cliff from edge. Much dead<br />
wood. Base is right on cliff edge. Looks like three<br />
trees - all connected with prostrate limbs covered with<br />
vegetation.<br />
Beneath canopy <strong>of</strong> pine <strong>and</strong> sweet chestnut. Growing<br />
from / next to remains <strong>of</strong> wall. Tag on N side.<br />
22
C20 929 S. rupicola<br />
C21 928 S. rupicola<br />
Grove,<br />
Churston<br />
Grove,<br />
91630 57033 5<br />
Churston 91625 57035 4<br />
C22 \ S. rupicola Fishcombe<br />
Grove,<br />
92009 56921 14<br />
C23 S. rupicola Churston<br />
Grove,<br />
91754 56963 3<br />
C24 S. rupicola Churston 91749 56957 3<br />
B2 939 S.porrigentiformis<br />
B8 \ S.porrigentiformis<br />
Babbacombe<br />
cliffs 92718 65595 9<br />
Babbacombe<br />
cliffs 92660 65591 12<br />
R1 926 S.porrigentiformis Redgate cliffs 93465 64985 4<br />
03 October SW <strong>of</strong> path below large Sycamore. Record made with<br />
2008<br />
03 October<br />
A. Byfield.<br />
2008<br />
03 October<br />
4m W <strong>of</strong> 20. Record made with A. Byfield.<br />
2008 Small sapling 1m from path w <strong>of</strong> 2.<br />
20 March<br />
2009<br />
20 March<br />
2009<br />
12<br />
September<br />
2008<br />
26<br />
September<br />
2008<br />
02 October<br />
2008<br />
Tree leaning out towards light, on edge <strong>of</strong> rocky<br />
quarried area.<br />
Tree partly beneath canopy <strong>of</strong> stunted beech tree (3-<br />
4m S)<br />
Multi-stemmed tree leaning below horizontal down<br />
slope. Stems running along ground. Approx 8m below<br />
path.<br />
Tall spindley tree completely shaded. N side <strong>of</strong> cliff on<br />
NW facing slope. W <strong>of</strong> railing on closed path, up on<br />
cliff ledge approx 10m above path, below bare rock<br />
face.<br />
Recently cut back. Stem sample taken at ground<br />
level. E side <strong>of</strong> stepped path up to Walls Hill, below<br />
big bluff used by climbers (13.6cm circ with 41 rings)<br />
R2 S.porrigentiformis Redgate cliffs 93478 64838 3 11 June 2010 V small stunted shrub almost under large rock.<br />
R3 \ S.porrigentiformis Redgate cliffs 93463 64906 4 19 July 2008 N side <strong>of</strong> large rock outcrop<br />
R4 \ S.porrigentiformis Redgate cliffs 93458 64901 3<br />
R5 \ S.porrigentiformis Redgate cliffs 93475 64847 4<br />
02 October Inaccessable. NE side <strong>of</strong> large rock outcrop, growing<br />
2008<br />
02 October<br />
from crack nr top.NGR taken from directly below.<br />
2008 On scree slope, 2m below R6. Young tree<br />
02 October Numerous stems hugging the rock, hard to tell if one<br />
R6 847 S.porrigentiformis Redgate cliffs 93474 64845 4 2008<br />
02 October<br />
plant. Growing close to R7 &R8.<br />
R7 \ S.porrigentiformis Redgate cliffs 93479 64844 3 2008<br />
02 October<br />
S <strong>of</strong> R6. one <strong>of</strong> a group <strong>of</strong> 3.<br />
R8 \ S.porrigentiformis Redgate cliffs 93479 64844 3 2008 Small shrub S <strong>of</strong> R6<br />
Young tree below R8. In grassl<strong>and</strong> & patch <strong>of</strong><br />
R9 \ S.porrigentiformis Redgate cliffs 93483 64843 3 19 July 2008 Cotoneaster sp.& loose rock.<br />
R10 \ S.porrigentiformis Redgate cliffs 93451 64849 3 19 July 2008 In scrubby patch <strong>of</strong> Cornus sp. <strong>and</strong> Rosa sp.<br />
R11 826 S.porrigentiformis Redgate cliffs 93446 64857 3 19 July 2008 30m from cliff top, behind rock outcrop above 10<br />
02 October In open low scrub, approx. 6m above path. Most<br />
R13 927 S.porrigentiformis Redgate cliffs 93485 64867 3 2008 leaves are juvenile form.<br />
R14 \ S.porrigentiformis Redgate cliffs 93444 64833 3<br />
02 October<br />
2008<br />
Inaccessible on rock face. NGR taken from approx 3m<br />
SE <strong>of</strong> tree 15<br />
23
R15 \ S.porrigentiformis Redgate cliffs 93444 64833 3<br />
R16 \ S.porrigentiformis Redgate cliffs 93507 64683 7<br />
R17 \ S.porrigentiformis Redgate cliffs 93539 64730 3<br />
R18 \ S.porrigentiformis Redgate cliffs 93522 64738 3<br />
02 October<br />
2008<br />
03<br />
September<br />
2008<br />
12 October<br />
2008<br />
12 October<br />
2008<br />
Inaccessible, growing with R14 beneath canopy <strong>of</strong><br />
Ash. Appears to be a young tree.<br />
Spindly tree, with some dead limbs. In narrow pass<br />
between Ansteys road <strong>and</strong> Redgate beach.<br />
Inaccessible on cliff above low tide level on S end <strong>of</strong><br />
Redgate beach, approx 8m above beach. Small<br />
spreading bush with many stems.<br />
Tree approx 10m from R17, below holm oak on rock<br />
outcrop. NGR taken from beach at nearest point to<br />
tree.<br />
12 October Tree approx 6m from R17, in shade <strong>of</strong> holm oak. NGR<br />
R19 \ S.porrigentiformis Redgate cliffs 93522 64744 3 2008 taken from beach at nearest point to tree.<br />
1 <strong>of</strong> 3 seen from Walls Hill with telescope - growing<br />
R20 S.porrigentiformis Redgate cliffs 934 648 31 May 2010 towards top <strong>of</strong> cliff nr iron railing<br />
1 <strong>of</strong> 3 seen from Walls Hill with telescope - growing<br />
R21 S.porrigentiformis Redgate cliffs 934 648 31 May 2010 towards top <strong>of</strong> cliff nr iron railing<br />
1 <strong>of</strong> 3 seen from Walls Hill with telescope - growing<br />
R22 S.porrigentiformis Redgate cliffs 934 648 31 May 2010 towards top <strong>of</strong> cliff nr iron railing<br />
Multi stemmed tree across rock face. N <strong>of</strong> scree slope<br />
R23 S.porrigentiformis Redgate cliffs 93476 64805 3 11 June 2010 behind gabions.<br />
In gorge at S end <strong>of</strong> beach cliff, below open rock face.<br />
Can be seen when climbing up from beach to pass<br />
R24 S.porrigentiformis Redgate cliffs 9349 6472 11 June 2010 between Redgate <strong>and</strong> Ansteys<br />
02 October Short shrubby bush noted by previous surveyors<br />
R12 \ S.porrigentiformis Walls Hill<br />
S.porrigentiformis Wall’s Hill<br />
S.porrigentiformis Wall’s Hill<br />
S.porrigentiformis Wall’s Hill<br />
S.porrigentiformis Wall’s Hill<br />
S.porrigentiformis Wall’s Hill<br />
S.porrigentiformis Wall’s Hill<br />
93509<br />
934<br />
934<br />
934<br />
934<br />
935<br />
935<br />
65239<br />
652<br />
652<br />
652<br />
652<br />
651<br />
651<br />
3 2008<br />
1 June 2010<br />
1 June 2010<br />
1 June 2010<br />
1 June 2010<br />
1 June 2010<br />
1 June 2010<br />
(Leigh Lock). Above flagstaff point -top <strong>of</strong> vertical cliff<br />
In area w <strong>of</strong> flagstaff point<br />
In area w <strong>of</strong> flagstaff point<br />
In area w <strong>of</strong> flagstaff point<br />
In area w <strong>of</strong> flagstaff point<br />
In area w <strong>of</strong> flagstaff point<br />
In area w <strong>of</strong> flagstaff point<br />
S.porrigentiformis Wall’s Hill 935 651 1 June 2010 In area w <strong>of</strong> flagstaff point<br />
24