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Can functional traits explain the dynamic of undesirable species in tropical grasslands?

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HAL Id: hal-01602994

https://hal.archives-ouvertes.fr/hal-01602994

Submitted on 2 Jun 2020

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Can functional traits explain the dynamic of undesirable species in tropical grasslands?

Simon Taugourdeau, Johann Huguenin, Gerard Balent, Vincent Blanfort

To cite this version:

Simon Taugourdeau, Johann Huguenin, Gerard Balent, Vincent Blanfort. Can functional traits explain the dynamic of undesirable species in tropical grasslands?. 53. Annual Meeting of the Association for Tropical Biology and Conservation, Jun 2016, Montpellier, France. 463 p., 2016, Annual Meeting of the Association for Tropical Biology and Conservation. �hal-01602994�

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Can functional traits explain the dynamics of

undesirable species in tropical grasslands?

Simon Taugourdeau1

Johann Huguenin1, Gérard Balent2 and Vincent Blanfort1 1 CIRAD, UMR SELMET, Montpellier, France

2 INRA, UMR DYNAFOR, Castanet-Tolosan, France

S71: Functional traits in tropical

agroecology

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Implanted Grasslands

In many tropical regions, grasslands are implanted

Implanted with one C4 perennial grass species

(generally)

Ranching systems

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Implanted grassland and spontaneous species

Implantation “Spontaneous” forage species Less palatable species Toxic species Undesirable species

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Implanted grassland and spontaneous species

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Economical and environmental costs

ATBC 06/23/2016 Implantation

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Agro-ecological management

Intensity and frequency of grazing Implantation

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Dynamics of undesirable species

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Understand the dynamic of the undesirables with

management.

Different species in the different tropical regions.

Use of functional traits to compare flora from different

regions

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Can functional traits explain the dynamic of

undesirable species in tropical grasslands?

with existing data from three tropical regions

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8 French Guyana Equatorial climate Reunion Island: Tropical to temperate climate New Caledonia:

Wet and dry tropical climate

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1229 historical surveys (G286,NC313,R630) 425/726 species in TRY TRY request for 82 traits

Data for 368 species

(26 traits with more 10% of value) List of undesirable and forage species

111 species with traits and undesirable/forage status

111 species with 14 traits

Cleaning and addition of data with Internet research

“A lot of key undesirable species are missing”

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111 species with 14 traits

Categories:

PGF(Plant growth form): 100% of the species

PP(Photosynthetic pathway): 100% of the species PW (Plant woodiness): 99% of the species

PL (Plant lifespan): 92 % of the species

DS (Dispersal Syndrome): 38% of the species PN (Plant Nitrogen fixation):92 % of the species LT (Leaf Type):89 %of the species

PRP (Plant Reproductive Period): 25% of the

species

Continuous:

LNC (Leaf Nitrogen Content):21% of the species SLA (Specific Leaf Area):19 % of the species SDM (Seed Dry Mass): 57 % of the species

SGR (Seed Germination Rate):37 % of the species PH (Plant Height): 91 % of the species

LL (Leaf Length): 29 % of the species

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111 species with 14 traits dissimilaritiesGower PCOA

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High functional diversity of forage species and undesirable species

Difference between forage and

undesirable

species

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111 species with 14 traits 74 undesirable species Gower dissimilarities Hierarchical Clustering 74 undesirable species in three functional groups

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U1: High PH, high SDM C3, W, Tree

U3: Low PH, low SDM C4,NW

U2: low PH, low SDM C3, NW ATBC 06/23/2016

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1229 surveys (G286,NC313,R630) 3 groups of undesirables P/A of groups of undesirables 44 variables of management and environment (climate and soil)

Only 8 common variables between the 3 regions

437 plots with 8 variables and associated surveys with

undesirable presence

No undesirable on Guyana survey

318 surveys on Reunion and New Caledonia

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8 variables Categories: RAIN: Rainfall in mm

AREA: plot area in ha

ACC: Accessibility (Easy, Med, Hard)

DIST: Distance plot farm (Short, Med, Far) FERT: Fertilization (Yes, No)

ROT: Rotary flail (Yes, No)

CHEM: Chemical Weeding (Yes, No) GRAZ: Grazing intensity (Int, Med, Ext)

Decision tree on the presence/absence of the different undesirable groups

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U1: Undesirable tree species

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Different decision trees between the type of undesirables species

U1: Undesirable tree species U3: C4 herb species

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Not yet…….

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Can functional traits explain the dynamic of

undesirable species in tropical grasslands?

with existing data from three tropical regions

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20 ATBC 06/23/2016

simon.taugourdeau@cirad.fr

Thanks for your attention Acknowledgements : V. Blanfort B.Dallaporta J. Huguenin G Balent

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