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Bi-annual Conference of International Society for Ecological Economics. From 01st 14th July 2004 To be held in Montreal Canada


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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 log-log plot of L urens is not constant, but varies systematically with spatial 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, 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 log-log plot of L urens is not constant, but varies systematically with spatial 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

Chair own and Name of Contact: CHEKUIMO TAGNE Georges Herbert, P. O. Box 8047 Yaounde-Cameroon (chekuimo@hotmail.com)
Table:
Fractal dimension (Db) of the two focal species




From National data (since 1987)

Species

200-100 km

100-50 km

50-20 km

20-10 km

10 to 5 km

5 to 2 km

2 to 1 km

Phyteuma


1

1

0.68

0.84

0.62

0.48

0.52

Lobelia

1

0.58

0

0

0.22

0

0.19







Form field surveys (June - July 2002)

Species

1 to 0.5 km

0.5 to 0.2 km

0.2 to 0.1 km

0.1 to 0.05 km

0.05 to 0.02 km

0.02 to 0.01 km

0.01 to 0.005 km

0.005 to 0.002 km

0.002 to 0.001 km

Phyteuma


0.58

1

1.22

1.19

1.46

1.34

1.38

1.49

1.30

Lobelia

0.58

0.55

1.13

1.44

1.25

1.49

1.47

1.08

1.09



F
igures
:

Figure 1: Resolution of map grid calculated from linear regressions of “log (cells occupied)” against “log(map scale)”.



Figure 2: L. urens’ predictions from 100m and 1 km (purple), and from 50 m and 200 m (dark blue).






Figure 3: P. orbiculare’s predictions from 100m and 1 km (bright green), and from 50 m & 200 m (red)



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