# Does plant functional composition in flower strips promote functional composition of carabid communities and weed predation in the adjacent rapeseed crop?

Marine Zwicke, Mickael Hedde, Sophie Joimel, Dominique Le Floch, Antoine Gardarin

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## To cite this version:

Marine Zwicke, Mickael Hedde, Sophie Joimel, Dominique Le Floch, Antoine Gardarin. Does plant functional composition in flower strips promote functional composition of carabid communities and weed predation in the adjacent rapeseed crop?. International Conference of Ecological Sciences Sfécologie-2016, Oct 2016, Marseille, France. hal-01592220

HAL Id: hal-01592220

https://hal.science/hal-01592220

Submitted on 5 Jun 2020

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# Does plant functional composition in flower strips promote functional composition of carabid communities and weed...

Poster · October 2016

DOI: 10.13140/RG.2.2.18991.74403

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Sophie Joimel
AgroParisTech

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Mickaël Hedde

French National Institute for Agricultural Research

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# Does plant functional composition in flower strips promote functional composition of carabid communities and weed predation in the adjacent rapeseed crop ?

ZWICKE MARINE¹†, HEDDE MICKAËL¹, JOIMEL SOPHIE², LE FLOCH DOMINIQUE³, GARDARIN ANTOINE³

## INTRODUCTION

* Rapeseed : high vulnerability to pests → huge pesticide inputs in rapeseed crops leading to negative effects on environment

* Flower strip sowing : agroecological lever to promote pest control by beneficial invertebrates,

* Literature : positive effects of flower strips on soil invertebrate abundance BUT the effects on pest control deserve more attention

**OBJECTIVE** : To understand the role of flower strip functional composition on the functional composition of carabid communities and the pest control in the rapeseed crops by a trait-based approach.

### GARGAMEL Project

(http://www.smach.inra.fr/Actions-cles/biodiv/Gargamel)

→ To test the effects of botanical composition in flower strips on biological control in the adjacent crops

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Flower strips
(food, habitats)

X

Cropping systems,
low inputs

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Beneficial
invertebrates

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Pest control

### Flower strip characterization

* 5 Flower strips (FS 1-5) sown in 2013 (6 x 44 m, n = 5)

* Botanical inventories in autumn 2015 (transect method)

* Aerial + root traits → Community weighted means (CWM)

* Micro-climate measurements

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Parameters : Shoot_mass : shoot biomass (g m⁻²), IRTsoil : infrared surface soil temperature (°C), LDMC*, leaf dry matter content (mg g⁻¹), moss : moss covering (%), PARsoil : solar radiation at soil surface (µmol s⁻¹ m⁻²), RDMC : root dry matter content (mg g⁻¹), Root大人 : root mass (g m⁻³), bare : bare soil proportion (%), tuft: tuft covering (%)

* Aerial traits from the literature (LEDA)

→ Flower strips differed according to soil micro-habitats and plant traits (LDMC et RDMC)

### Effects of flower strips on weed predation

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→ Weed predation is correlated to carabid communities characterized :

- diurnal and phytophageous activities

- intermediate body length

### Effects of flower strips on Carabid communities

* Inventories in autumn 2015 (pitfall traps) in flower strips and in the adjacent rapeseed crops (2 dates x 5 rep)

* Morphological and behavioural traits (BETSI) → Community weighted means (CWM)

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<table><thead><tr><td></td><td>Crop vs Flower strip</td><td>Flower Strip composition</td></tr></thead><tbody><tr><td>Species richness</td><td>P < 0.001</td><td>NS</td></tr><tr><td>Shannon</td><td>NS</td><td>NS</td></tr><tr><td>Wing: Macropterous</td><td>P < 0.001</td><td>NS</td></tr><tr><td>Food: Seeds</td><td>.</td><td>NS</td></tr><tr><td>Food: Roots</td><td>P < 0.001</td><td>NS</td></tr><tr><td>Food: Animals</td><td>NS</td><td>NS</td></tr><tr><td>Activity: Diurnal</td><td>P < 0.01</td><td>NS</td></tr><tr><td>Mean body lenght</td><td>P < 0.05</td><td>NS</td></tr></tbody></table>

→ Differences in functional composition of carabid communities between flower strips and the adjacent rapeseed crops

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→ Rapeseed crops : high filtering on carabid body length

→ Flower strips : filtering removal, differences in body length classes

## CONCLUSION

* Functional composition of flower strips shapes functional composition of carabid communities BUT NOT in the adjacent rapeseed crop.

* Weed predation is correlated to carabid community weighted means BUT these correlations are time-dependent, probably due to carabid phenology and/or resource availability.

### AFFILIATIONS :

¹UMR ECOSYS, PÔLE ECOTOXICOLOGIE, INRA VERSAILLES-GRIGNON - 10 ROUTE DE ST CYR, 78000 VERSAILLES

²UMR ECOSYS, INRA, AGROPARISTECH, UNIVERSITÉ PARIS-SACLAY, 78850, THIVERVAL-GRIGNON, FRANCE

³AGROPARISTECH – UMR AGRONOMIE, BÂTIMENT EGER, 78850 THIVERNAL-GRIGNON

† UPEC - FACULTÉ DES SCIENCES ET TECHNOLOGIE - IEES PARIS - 61, AVENUE DU GÉNÉRAL DE GAULLE, 94010 CRETEIL

### Acknowledgements : This project was funded by the Labex BASC. We also acknowledge Adrien

de Villenaut, Gilles Grandseau, Jean-Pierre Pétraud, Amélie Trouvé, Christelle Marrauld

BETSI : Base de données BETSI, Hedde M, et al. 2012 : BETSI, a complete framework for

studying soil invertebrate functional traits. XVI ICSZ—International Colloquium on Soil Zoology, Coimbra.

LEDA : Kleyer et al. The LEDA Traitbase: A database of life-history traits of Northwest

European flora. Journal of Ecology 96: 1266-1274.