This study examined the phylogenetic diversity of plant communities in rock outcrop patches in southeastern Brazil. The researchers analyzed 22 plant species from 7 families found across 26 vegetation patches of varying sizes. They calculated two metrics (NRI and NTI) to determine if co-occurring species within each patch were phylogenetically clustered or evenly dispersed. Results showed no significant phylogenetic structure, suggesting species presence in each patch was randomly distributed. Richness was positively correlated with patch area. While MPD increased and MNTD decreased with the number of taxa, the relationships were weak. Further analysis including species abundance and traits is needed.

1. Community Ecology & Function
Phylogenetic Diversity in Rock Outcrop Plant Communities
in Southeastern Brazil
Colmenares S.L.T.1, Rosado B.H.P.2, de Mattos E.A.3
1 Universidade Federal do Rio de Janeiro – Programa de Pós Graduação em Ecologia
2 Instituto de Pesquisa Jardim Botânico do Rio de Janeiro ,
3 Universidade Federal do Rio de Janeiro – Departamento de Ecologia
Symposia
DNA barcodes and beyond: Developing and utilizing
community-wide DNA sequence data to understand
ecology and evolution of tropical biodiversity

2. Analysis of the phylogenetic structure of communities
provide insights into the ecological processes that
organize them (Webb, 2000)
…
(Vamosi, et al. 2009)

3. ROCKY OUTCROPS OR INSELBERGS
“Xeric islands in a tropical matrix”
great environmental heterogeneity

4. Vegetation is found forming elliptical
soil-islands or patches of varying size
and soil depth

5. These islands exhibit a clearly
defined border, enabling precise
delimitation of area and species
composition
Increases in area and substratum depth contain
an apparent gradient on water and nutrient
availability, which may restrict establishment of
some plant species

6. Smaller patches
provide harsher
environmental postulated that species’ patch
Thus, we
conditions than
composition will vary according to size
larger ones, probably
filtering thevariation and species’ phylogenetic
species
according to their relatedness
ability to deal with
environmental
stresses

7. A set of 26 vegetation patches
of varied sizes (between 0.5
m2 and 30 m2) was censed to
construct a presence/absence
species vs. patch area matrix

8. PHYLOGENETIC COMMUNITY STRUCTURE
22 species - 7 families

9. PHYLOGENETIC COMMUNITY STRUCTURE
We aim to explore if
co-occurring species
Com 1
within eachClustered
vegetation patch are
Evenly
dispersed
phylogenetic 2evenly
Com
dispersed or
clustered

10. The Mean Phylogenetic Distance (MPD) and the Mean Nearest Taxon
Phylogenetic Distance (MNTD) were calculated and tested against null
distribution of 999 null communities to obtain the standardized indexes:
Net Related Index (NRI) and Nearest Taxon Index (NTI)
NRI or NTI ≥ +1.96 Clustered
When:
Evenly
NRI or NTI ≤ - 1.96
dispersed

12. RICHNESS vs. AREA
14
12 We observed a
10 significantly
RICHNESS
8 relationship
6
between richness
4 R² = 0.256
2
and patch area
0
-5 5 15 25 35
AREA

13. NRI
2
1.5
1
NRI and NTI values were
0.5
0
not significantly different
NRI
-0.5 0
-1
10 20 30 40 from randomly generated
-1.5
-2
null communities
-2.5
NTI Thus, we have some evidence
2
1.5 that the presence of species of
1
0.5 species in each vegetation
0
-0.5 0 10 20 30 40
NTI
patch presents random
-1
-1.5 phylogenetic distribution
-2
-2.5

14. Further studies are necessary to
test whether the above results
can remain when variation in
abundance of species and
functional trait diversity are
included on the analysis

15. So… What can we expect ?
?
?
Webb et al., 2002

16. ACKNOWLEDGMENTS
TO MY MOTHER
PARQUE ESTADUAL
SERRA DA TIRIRICA –
NITERÓI, RJ
TO PROF.
LÚCIA G. LOHMANN

21. MPD
y = 3.334x + 484.4
700 R² = 0.175
600
500
400
MPD
300 MPD was positively, but weak
200
100 related to the patch area and
0
0 5 10 15 20 25 30 35 number of taxa respectively
Area (r2=0.18, pvalue=0.026;
r2=0.30, pvalue=0.0024), whereas
MNTD MNTD decreased with increasing
1000
800
y = -5.503x + 503.6
R² = 0.093
number of taxa
(r2=0.509, pvalue=0.000020).
MNTD
600
400
200
0
0 5 10 15 20 25 30 35
Area

22. NTI MPD
2 700
600
1 500
400
MPD
0 300
NTI
0 5 10 15 20 25 30 35 200
-1
100
-2 0
0 5 10 15 20 25 30 35
-3
Area Area
NRI MNTD
2 1000
800
1
600
MNTD
0
400
NRI
0 5 10 15 20 25 30 35
-1 200
-2 0
0 5 10 15 20 25 30 35
-3
Area Area

23. AND WHAT ABOUT
PHYTLOGENETIC RELATEDNESS
BETWEEN CO-OCURRING SPECIES
AT EACH VEGETATION PATCH?