three-year maintained drought reduces diversity in gypsum ... · background observational studies...

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Three-year maintained drought

reduces diversity in gypsum

annual plant communities

Roberto, López-Rubio, David S. Pescador,

Adrián Escudero, Ana, M. Sánchez

roberto.lopezr@urjc.es

Background

Observational studies

Experimental studies

Luzuriaga et al. (2012). PLoS ONE 7: e41270.

Our study

López-Peralta et al. (2016). Annals of Botany 117:1221-1228

López-Peralta et al. (sent). Journal of Ecology

Variability of the rainfall pattern

Experimental field study under global change

scenario

Which are the main factor affecting the assemblage of these communities?

Our study

Partial rain exclusion applied to the whole community

Field experimental approach

Rain reduction of rainfall and soil humidity

MODEL PREDICTIONS:

SIMULATION OF PREDICTED FUTURE CONDITIONS

Questions

How will the drought treatment affect community assembly?

Will the drought generate a change in species composition?

Will this change be based on a functional species sorting?

Will this change produce a decrease in functional diversity?

Freq

uen

cy

Trait

CWM

Freq

uen

cy

RaoQ

Species richness and cover

Trait

Study site

Study place Biotic conditions

Mean annualPrec (365 mm) and

Tª (13-15 °C)

Cover of perennial plants around 30 %

Biological Soil Crust

Study site

More than 100 species and 26 families;

up to 38 species/0.25 m2

Annual plant communityBiotic conditions

25 cm

Experimental design

Block

Control Drought

Cover is annually recorded at the flowering peak

3 Years of data collection(by now)

7 Blocks2 Treatments plot 3x3 m

4 subplot 25x25 cm3 m

SLALDMC

Plant HeightMax WidthRoot/shoot biomass

Seed massReproductive/vegetative biomass

Functional traits

Regeneration

Leaf

Plant

Resource uptake

CWM

RaoQ

Mean value of a trait based on species abundances

Variability of a trait in the community (Functional diversity)

Soil humidity monitoring

Data analyses

GLMMs ~ Treatment x BSC’s cover + 1|Year + 1|Block/Subplot

Fix factor Random factors

Covariate

PERMANOVAs

Reduction of:50-60% at 5 cm20% at 10 cm

Each year composition ~ Treatment x BSC’s cover x Block, 999, Bray-Curtis

Taxonomic and

functional indices

Results and Discussion

Richness 65 species and 26 families90% cover

Mea

ns

P < 0.05 P < 0.05 n.s.Treatment

Richness Inverse Simpson index Evenness

Treatment*BSC No significance in any model

Composition

2016 2017 2018

n.s. P < 0.01 P < 0.001

Results and Discussion

Functional composition

Regeneration

Leaf

Plant

SLA

CW

M’s

mea

n

P < 0.001

Results and Discussion

Results and Discussion

Functional composition

Regeneration

Leaf

Plant

Wid

th(m

m)

CW

M’s

mea

n

Hei

gth

(mm

) C

WM

’sm

ean

P < 0.05

P < 0.05

Functional composition

Regeneration

Leaf

PlantSe

ed

mas

s (µ

g) C

WM

’s m

ean

Rep

/Veg

CW

M’s

mea

n

P < 0.01

P < 0.05

Results and Discussion

Results and Discussion

Regeneration

Leaf

Plant

Control Drought

Resourceuptake

Functional composition

Communities under the rain exclusion have a more stress-resistant functional design

Functional diversity

Leaf Plant

P < 0.01 P < 0.05

Results and Discussion

Conclusions

Drought treatment reduced both taxonomic and functional diversity

We observed a functional convergence towards a more stress-resistant design when drought

treatment was applied

Control Drought

This was possibly due to a reduction in growth period associated with the

drought treatment

Future lines

Measure the importance of intraspecific trait variation

Thank you for your attention

roberto.lopezr@urjc.es

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