are vegetation classes good proxies for changes in floristic composition in amazon forests? thaise...
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Are vegetation classes good proxies for changes in floristic composition
in Amazon forests?Thaise Emilio, Bruce Nelson, Juliana Schietti, Sylvain
Desmolière, Juliana Ortega & Flávia Costa
Manaus, 2008
Vegetation maps was used sistematically in conservation planning since 1999 for represent beta diversity of brazilian Amazon 1
This use assumes that there is a correlation between species distribution and vegetation types 2
VEGETATION CLASSES AS PROXIES FOR BETA DIVERSITY
1 Ferreira et al .2001, Nelson & Oliveira 2001; 2 Ferrier & Watson 1997
FOREST HOMOGENEITY?
Environmental determinismDistance-decay relationship
Tuomisto et al. 2003, Condit et al. 2002
Evaluate vegetation types as surrogates for canopy trees beta diversity with tree different aproaches:
(1)Analising the distance-decay relationship between plots;
(2)Examining the congruence between vegetation types and beta diversity spatial patterns;
(3)Testing the floristic separation strength between vegetation types.
AIM
2,719 standard inventories of 1 ha; (20 x 500 m) trees >31.2 cm DBH
Centroids of 1,196 inventories grouped into sets of 4, generating 296 groups
ORIGINAL DATABASE , RADAMBRASIL ANALYZED DATA : genus level dets; more evenly-spaced grouped inventories
12 vegetation types (Aap, Abb, Abp, Asc, Asp, Dae, Dau, Dbe, Dse, Dsu, LO, Fs)
45 vegetation types
DATABASE
EVALUATED VEGETATION TYPES
Aap = Inundated open forest with palms (N = 18)
Abb = Lowland open forest with bamboos (N = 8)
Abp = Lowland open forest with palms (N = 30)
Asc = Upland open forest with lianas (N = 35)
Asp = Upland open forest with palms (N = 29)
Dae = Inundated dense forest with emergent trees (N = 23)
Dau = Inundated dense forest without emergent trees (N = 6)
Dbe = Lowland dense forest with emergent trees (N = 80)
Dse = Upland dense forest with emergente trees (N = 47)
Dsu = Upland dense forest without emergent trees (N = 4)
LO = Sand forest(N = 8)
Fs = Semideciduousdry forest(N = 8)
RESULTS FLORISTIC DISTANCE x GEOGRAPHIC DISTANCE
RESULTS SPATIAL FLORISTIC GRADIENT CONGRUENT WITH FOREST CLASSES
Floristic composition of canopy trees changes gradually in space (A). Spatial floristic variation at genus level is congruent with the distribution of four general forest classes (B). Differences occurs mainly in SE, Acre region. This spatial pattern is similar to edaphic-climate variation patterns.
RESULTS FLORISTIC HETEROGENEITY WITHIN VEGETATION CLASSES
Internal floristic heterogeneity (see beta diversity values) is present in all vegetation classes, including the finer classes of the hierarchy. Turnover is greater in the N/S direction than in the E/W direction
RESULTS FLORISTIC SEPARATION BETWEEN VEGETATION CLASSES
Significant floristic differences (asterisks) occur between some, but not all vegetation types. Strength of separation for selected type pairs is shown in 2-dimension NMDS and is independent of the range of variation or number of inventories. Correlated geographic effects have not been removed.
Abb Abp Asc Asp Dae Dau Dbe Dse Dsu LO Fs0.171* 0.062* 0.093* 0.101* 0.000 0.000 0.069* 0.088* 0.088* 0.180* 0.180* Aap
- 0.121* 0.088* 0.127* 0.188* 0.242* 0.104* 0.121* 0.267* 0.365* 0.234* Abb- 0.060* 0.049* 0.071* 0.000 0.027* 0.036* 0.000 0.090* 0.133* Abp
- 0.000 0.118* 0.055* 0.094* 0.051* 0.000 0.115* 0.070* Asc- 0.116* 0.065* 0.069* 0.036* 0.000 0.125* 0.117* Asp
- 0.000 0.058* 0.086* 0.000 0.117* 0.173* Dae- 0.034* 0.043* 0.000 0.205* 0.184* Dau
- 0.031* 0.000 0.040* 0.094* Dbe- 0.000 0.070* 0.101* Dse
- 0.187* 0.199* Dsu- 0.286* LO
- Fs
COMPARISON BETWEEN FLORISTIC AND VEGETATION SIMILARITY
At genus level some forest types are not floristically different. UPGMA dendrogram is different from the hierarchy inherent in the logic of the RADAM classification system. Three geographically restricted vegetation types are most distinct from all other types -- possibly because geographic distance effects cannot be removed.
MAIN CONCLUSIONS AND FINAL CONSIDERATIONS
At genus level, floristic composition of canopy trees changes gradually at Brazilian Amazonia scales;
Two near areas of different vegetation types may be more similar than two distant areas of same vegetation types;
Floristic turnover is greater in the N/S than in the E/W direction;
Physiognomic vegetation classes exhibit different amounts of internal floristic variation, particularly if they cover different latitudinal distances.
At species level, this differces may be greather and more irregular distributed.
The use of vegetation types as direct surrogate of beta diversity are not recomended for canopy trees.
