variation in botanical activity in the british isles 1836 ... in botanical recording tim rich...
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Variation in botanical activity in
the British Isles 1836-1988:
how can we assess change?
Tim Rich
What do these maps tell us about the species?
Atlas of British flora, 1962
Date classes:
Dark blue 1987-1999
Light blue 1950-1986
Pale blue pre 1950.
(New Atlas, BSBI)
Neottia cordata
Lesser twayblade
Problems assessing change: Example 1
Survey 1,
50% coverage
Survey 2,
50% coverage
Random selection of the
1 in 9 squares from
BSBI monitoring
scheme Neotiia cordata
data, compare 2
surveys of STABLE
population
Survey 1,
50% coverage
47 squares
Survey 2,
50% coverage
48 squares
Two surveys combined
– apparent 36% decline?
● both surveys
O 1950-1960 (49% coverage)
+ 1987-1988 (56% coverage)
Conclusion:
No decline
And when revisited 8 ‘old’
squares, refound
immediately in 6
BSBI Monitoring Scheme (actual data)
= native 1987-2007
o = native pre-1987
x = alien• total 45 native sites in 9 squares
• by 1996 only 9 sites left (80% decline)(Biodiversity and Conservation 7: 915 (1998))
Problems assessing change: Example 2
Noccaea (Thlaspi) perfoliatum, Cotswold Pennycress
Square Date Rec. Locality
ST31 29/05/1891 AB Charlbury
ST31 03/1884 GCD Stonesfield
ST31 05/1886 GCD Stonesfield
ST31 22/04/1935 PCL Stonesfield Quarry
ST31 04/1945 JGD Stonesfield
ST31 18/04/1946 JEL Stonesfield Quarry
ST31 24/04/1948 - Stonesfield, railway
ST32 08/05/1931 KEK Fawler
ST32 16/05/1953 DMc Fawler Pits
Different
sites/habitats
Different
dates
Different
recorders
• 290 Thlaspi records traced in herbaria, literature, databases,
correspondence etc.
• A record=unique combination of locality, date, recorder, habitat
0
2
4
6
8
10
12
1830 1840 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980
Year
Nu
mb
er
of
reco
rds
What is happening to Thlaspi?
• plot number of records for each year; hard to interpret
trend line
number of Thlaspi records per year (10-year running average)
• running averages also hard to interpret
•fluctuations but apparently ‘increasing’
0
5
10
15
20
25
30
35
40
1830
1840
1850
1860
1870
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
Decade
Nu
mb
er
of
reco
rds
• all trendlines show Thlaspi is increasing, yet we know it is decreasing
• number of records is NOT a good measure of frequency
Number of records per decade
How can we find out what is really
happening to Cotswold Pennycress?
The problem is that there is a lot of variation in recording:
• not systematic in time or space
• a lot more recent records than historical records
• some areas have more records than others
• cannot compare like with like
So I tried to quantify the variation in recording
• took 15 years!
• results give a broad generalisation
Botanical records are made by individuals:
Eleanor Vachell 1879-1948
Number of herbarium specimens
0
50
100
150
200
250
300
1890 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945
Year
Nu
mb
er
of
sp
ecim
en
s
Number of publications each year
0
1
2
3
4
5
6
7
19
46
19
52
19
58
19
64
19
70
19
76
19
82
19
88
19
94
Year
5 y
ea
r a
ve
rag
e
C. A. Stace
A. O. Chater
J. G. Dony
E. Vachell publications
0
1
2
3
19
19
19
22
19
25
19
28
19
31
19
34
19
37
19
40
19
43
19
46
19
49
Year
No
. p
ub
lic
ati
on
s
Individuals
• have very variable contributions depending on
personal circumstances
• tend to collect locally, and in botanical hotspots
• tend to publish locally but sporadically
• behave as individuals, but also contribute to organised
county and national projects
• Individuals are also organised into groups/societies etc
Botanical Societies etc
Density of botanical societies…
National: How many botanists?
Sources of data:
• Membership lists (BSL, BEC – incomplete!, BSBI)
• collectors listed in British and Irish herbaria (Kent & Allen 1984)
0
500
1000
1500
2000
2500
3000
18
30
18
40
18
50
18
60
18
70
18
80
18
90
19
00
19
10
19
20
19
30
19
40
19
50
19
60
19
70
19
80
19
90
Year
Nu
mb
er
of
me
mb
ers
or
co
lle
cto
rs
Botanists to population as a whole
0
1000
2000
3000
4000
5000
6000
1831
1851
1871
1891
1911
1931
1951
1971
1991
Census Year
National population
Botanists
proportion
0
20
40
60
80
100
1830
1840
1850
1860
1870
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
Year
Rela
tive n
um
ber
of
bo
tan
ists
Interpretation of number of botanists
• Probably underestimated
Where are the
botanists?
Sources:
Membership lists
1836, 1936, 1952, 1999
• most botanists in major
urban areas and cities
•Highly correlated in space
through time
• for 1999 British membership,
a constant proportion of
national population (1991
census)
Hypothesis:
The number and distribution of botanists will determine
the amount of records (information) in space and time
Compiled data on:
• Literature records
• Herbarium records
• Database records
Much of the data from these sources is inconsistent, is
incomplete, is indirect, has changed with time, etc.
Literature sources1. Simpsons Bibliographic index (1960)
2. 2. BSBI database (1960-1988)
0
300
600
900
1200
18
60
18
70
18
80
18
90
19
00
19
10
19
20
19
30
19
40
19
50
19
60
19
70
19
80
19
90
Year
Nu
mb
er
of
pa
ge
s p
ub
lis
he
d
Literature 1:
number of pages published by botanical societies
5 year
running
average
Literature 2:
Number of publications each year (all sources and types)
0
100
200
300
400
500
600
700
800
900
1000
1830
1840
1850
1860
1870
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
Year
Nu
mb
er
of
pu
bli
cati
on
s
Number of publications
for each county
(corrected for area)
18
30
18
40
18
50
18
60
18
70
18
80
18
90
19
00
19
10
19
20
19
30
19
40
19
50
19
60
19
70
19
80
19
90
Year
Nu
mb
er
of
pu
blic
ati
on
s
(5-y
ea
r m
ov
ing
av
era
ge
)
Sussex
Cardiganshire
Durham
Forfar
Tipperary
Londonderry
Literature 3:
Number of county floras published each year
0
1
2
3
4
5
6
1830
1840
1850
1860
1870
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
Year
Nu
mb
er
of
Flo
ras
Number of county floras
for each county
(corrected for area)
Summary of variation
in literature
01020304050
60708090
100
18
30
18
40
18
50
18
60
18
70
18
80
18
90
19
00
19
10
19
20
19
30
19
40
19
50
19
60
19
70
19
80
19
90
Year
Re
lati
ve
lit
era
ture
pu
bli
ca
tio
n (
5 y
ea
r ru
nn
ing
av
era
ge
)
Herbarium recordsSource: National Biological Records Centre databases
0
500
1000
1500
2000
2500
3000
1830
1840
1850
1860
1870
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
Year
Nu
mb
er
of
herb
ari
um
co
llecti
on
s
Number of herbarium
collections (corrected
for area)Source: National Biological Records
Centre databases
Database records dated to year (excludes summary dates)
Source: National Biological Records Centre databases
0
1
2
3
4
5
6
7
8
1930
1940
1950
1960
1970
1980
1990
Year
Nu
mb
er
of
field
reco
rds
(hu
nd
red
s o
f th
ou
san
ds)
Geographical variation in database records…
• very high variation in national database due to
incomplete inclusion of records from flora projects
However, BSBI Monitoring Scheme (Rich & Woodruff
1990) allows relationship to be explored
• 1 in 9 squares surveyed systematically in 1987 and 1988
• detailed records kept of species, location, dates, hours spent
recording, etc
• nearly 985,000 records, 9630 record cards, 1600 botanists, 21235
hours, 2660 taxa, etc.
Number of botanists
who recorded in each
square
Time spent recording in
each square
Number of records
Number of species
Relationship between number of species and time spent
recording for each square
-200
0
200
400
600
800
1000
0 50 100 150 200 250 300 350
Hours spent recording
Nu
mb
er
ofs
pecie
s
Overall clear links between botanical activity and
amount of information: more botanists spending more
time recording in each square results in more records
and more species…
So can we build a picture of recording activity in space
and time?
• clearly many problems with the data
• but general patterns the same
Data, where reliable, given equal weight to produce a
crude overall model of botanical activity…
0
10
20
30
40
50
60
70
80
90
100
1830
1840
1850
1860
1870
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
Year
Rela
tive r
eco
rdin
g e
ffo
rt
Integrated summary of variation in time, from compilation of
literature, herbarium and database records
total recording effort
number of botanists
Integrated
geographical
variation in recording
effort ranked into 5
classes from
high recording effort
(black)
to
low recording effort
(white)
Conclusions
• first attempt to reconstruct recording history of British Isles;
the amount of recording activity has increased with time
key times
1. Druce - change from exchange club to botanical society,
2. BEC to BSBI 1948
• botanical data only reliable/representative from 1890s
• recording activity concentrated in areas where botanists live
rather than botanical hotspots
• quality and quantity of information has changed with time
• results must be taken as broad trends only, a useful tool to
help you think
• could refine models, perhaps including number of botanists
Applications 1. Correcting historical frequencies for effort:Rich, T. C. G. & Karran, A. B. (2006). Botanical Journal of the Linnean Society 152: 279-302
Thlaspi data corrected for recording effort: can see a more realistic trend!
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1935 1945 1955 1965 1975 1985 1995 2005 2015 2025 2053
Decade
Co
rrecte
d,
extr
ap
ola
ted
nu
mb
er
of
sit
es
Applications 2. Thlaspi predicted extinction date: 2011
For full details:
Rich, T. C. G. (2006). Floristic changes in the British Isles: geographic and temporal variation in botanical activity 1836-1988. Botanical Journal of the Linnean Society 152: 303-330.
Rich, T. C. G. & Karran, A. B. (2006). Floristic changes in the British Isles: Comparison of techniques for assessing changes in frequency of plants with time. Botanical Journal of the Linnean Society 152: 279-302.
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