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Bi-annual Conference of International Society for Ecological Economics.

From 01st - 14th July 2004

To be held in Montreal

Canada.

http://www.iseemontreal2004.com/teaser/teaser_new.html

Fractal patterns in species distributions of some British scarce plants

By

Georges Herbert, CHEKUIMO TAGNE

P. O. Box 8047 Yaounde

Cameroon

Tel.: +237 761 5579

+237 220 8205

Email: azpa01@ureach.com chekuimo@hotmail.com

Type of Presentation

: the abstract is intended for a

Poster.

Name of Invited Symposium

: Bi-annual Conference of International Society for Ecological

Economics, from 01st - 14th July 2004, to be held in Montreal, Canada.

Authors and Addresses

:

Georges Herbert, CHEKUIMO TAGNE,

P. O. Box 8047

Yaounde-Cameroon (

chekuimo@hotmail.com

)/

Kunin, W. E

., Faculty of Biological

Sciences, school of Biology, Centre for Biodiversity and Conservation, Leeds University-UK

(

W.E.Kunin@leeds.ac.uk

)/

Pocock, M.

, Faculty of Biological Sciences, school of Biology,

Centre for Biodiversity and Conservation, Leeds University-UK

(

m.j.o.pocock@leeds.ac.uk

)/

Aston, R.

The theme of the 2004 meeting

: "Challenging Boundaries: Economics, Ecology and

Governance"

Topic Area

: Conservation issues concerning plants

Title

: Fractal patterns in species distributions of some British scarce plants

Abstract

: The analysis, measurement, and management of species abundance is central to ecology and conservation biology, but it has proved difficult to find a single index that adequately reflects the commonness or rarity of species across a range of spatial scales. The spatial distribution and fractal structure of two British scarce plants,

Lobelia urens

(heath lobelia) and

Phyteuma orbiculare

(round-headed rampion), have been examined at several different scales. The two species have similar degrees of local patchiness at scale coarser than

50 km and have contrasting coarse-scale between 50 km and 1 km scales, but differed consistently in the slopes of their scale-occupancy curves distributions at scale finer than 1 km. The slope of the spatial log-log plot of

L urens

is not constant, but varies systematically with scale, and from habitat to habitat at the same spatial scale. Abundance estimates suggest that the species

P. orbiculare

is found to be clumped at all scales, whereas

L. urens

is dispersed at intermediate scale. Fractal dimension analysis suggests that this changes through scale. The distribution varied in their pattern from highly clumped to randomly dispersed.

Fairly predictions of

L. urens

can be made from 50 m and 200 m.

Fractal dimension, Conservation issues, conservation schemes

Abstract

: The analysis, measurement, and management of species abundance is central to ecology and conservation biology, but it has proved difficult to find a single index that adequately reflects the commonness or rarity of species across a range of spatial scales. The spatial distribution and fractal structure of two British scarce plants, <i>Lobelia urens</i>

(heath lobelia) and <i>Phyteuma orbiculare</i> (round-headed rampion), have been examined at several different scales. The two species have similar degrees of local patchiness at scale coarser than 50 km and have contrasting coarse-scale between 50 km and 1 km scales, but differed consistently in the slopes of their scale-occupancy curves distributions at scale finer than 1 km. The slope of the systematically with spatial log-log plot of <i>L urens</i> is not constant, but varies scale, and from habitat to habitat at the same spatial scale.

Abundance estimates suggest that the species <i>P. orbiculare</i> is found to be clumped at all scales, whereas <i>L. urens</i> is dispersed at intermediate scale. Fractal dimension analysis suggests that this changes through scale. The distribution varied in their pattern from highly clumped to randomly dispersed. Fairly predictions of <i>L. urens</i> can be made from 50 m and 200 m.

<i>Fractal dimension, Conservation issues, conservation schemes</i>

Chair own and Name of Contact

:

CHEKUIMO TAGNE Georges Herbert,

P. O. Box

8047 Yaounde-Cameroon

(chekuimo@hotmail.com)

CHEKUIMO_Bi-annual Conference ofISEE

2

Table

:

Fractal dimension (

D

b

) of the two focal species

Species

200-100 km 100-50 km

From National data (since 1987)

50-20 km 20-10 km 10 to 5 km

Phyteuma

Lobelia

1

1

1

0.58

0.68

0

0.84

0

0.62

0.22

Species

Phyteuma

1 to

0.5 km

0.58

0.5 to

0.2 km

1

0.2 to

0.1 km

Form field surveys (June - July 2002)

0.1 to

0.05 km

0.05 to

0.02 km

0.02 to

0.01 km

0.01 to

0.005 km

1.22 1.19 1.46 1.34 1.38

5 to 2 km

0.48

0

0.005 to

0.002 km

1.49

0.58 0.55 1.13 1.44 1.25 1.49 1.47 1.08

Lobelia

Figures

:

2 to 1 km

0.52

0.19

0.002 to

0.001 km

1.30

1.09

Lobelia urens and Phyteuma orbiculare

1000000

100000

10000

1000

100

10

Phyteuma

Lobelia

1

Log Scale (km)

Figure 1

: Resolution of map grid calculated from linear regressions of “log (cells occupied)” against “log(map scale)”.

CHEKUIMO_Bi-annual Conference ofISEE

3

Lobelia urens

100000

10000

1000

100

10

Lobelia

Predictions from 100m and 1 km

Predictions from 50 m and 200 m

1

Log Scale (km)

Figure 2

:

L. urens

’ predictions from 100m and 1 km (purple), and from 50 m and 200 m

(dark blue).

Phyteuma orbiculare

1000000

100000

Phyteuma orbiculare

Predictions from 100m and 1 km

Predictions from 50 m and 200 m

10000

1000

100

10

1

Log Scale (km)

Figure 3

:

P. orbiculare’s

predictions from 100m and 1 km (bright green), and from 50 m &

200 m (red)

CHEKUIMO_Bi-annual Conference ofISEE

4

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