Plants and arthropods as bio-indicators in vineyard agroecosystem

Transcription

1 Plants and arthropods as bio-indicators in vineyard agroecosystem Trivellone V., Pedretti A., Caprani M., Pollini L., Jermini M., Moretti M. IOBC, Ascona, October

2 Context Agriculture: management of terrestrial ecosystems to serve human needs needs for food crop-associated biodiversity Agri-environmental strategies for conserving biodiversity Reliable bio-indicators to assess their effectiveness 2

3 Objectives 1. Identify factors shaping the plant and arthropod assemblages in vineyard agroecosystem 2. Select indicator species (target taxa) responding to environmental and anthropogenic stressors 3

4 Study sites selection Arc GIS software (ESRI 2010) 48 vineyards NE-NW (n= 24) SE-SW (n= 24) Aspect Flat Slope Flat Slope Slope A Antropic Open O F area area Forest A O F A O F Landscape 200m radius Interviews about management practices 4

5 Study sites selection Southern Swiss Alps as study region you are here 5

6 Data sampling response variables Taxa Trophic level Plants primary producer Leafhoppers herbivore Spiders carnivore Ground beetles carnivore 6

7 Data sampling - vegetation 2 relevés (June and August) 1x1m n = 10 quadrats/vineyard/period % vegetation cover 7

8 Data sampling - arthropods Pitfall traps D-vac Beating tray 7 sampling periods n = 2 samples/vineyard/period/method n adults n species > 10 m 8

9 Data sampling response variables Taxa Ntot species Ntot adults New CH Plants Leafhoppers Spiders Ground beetles

10 Data sampling explanatory variables Manag Taxa are affected Topog by. Edaph Land 10

11 Data sampling management Mowing Fertilizer Herbicide Insecticide Fungicide 11

12 Data sampling topographic degrees Altitude Slope Aspect Solar Radiation Solar time 12

13 Data sampling edaphic Soil Analysis: - Texture (% Silt, Clay and sand) - Nutrient (N, NO3, MO ) - Other properties Vegetation structure: - %Herbs, %Forbs %Soil, %Rock % Mosses 13

14 Data sampling landscape Composition within 200 m radius Landscape units 200 m Vineyards Open green areas Fallows Single trees Edge rows Woodland Settlement Arc Map 10 and Digital elevation model (DHM25 swisstopo) with a resolution of 25 x 25 m (Vector , SWISSTOPO,DV033594). 14

15 Analysis scheme sites species Spiders Carabids species manag edaph topog lands Leafhoppers Plants Abundance data 48x6 48x15 48x5 48x6 Data transf Forward selection Step 1 Variation partitioning Step 2 Redundancy analysis Step 3 Multi-Regression Tree Step 4 Indicator Value Analysis Site groups Step 5 15

16 Results Step1 Overall 12 significant variables Plants Leafhoppers Spiders Ground beetles Management Herbic Herbic Herbic Herbic Mowing Mowing Mowing Topographic Slope Slope Slope Slope Altitude Altitude Altitude Solar_rad Solar_rad Edaphic MO N N N Sand grass_layer grass_layer Sand NO3 Clay Landscape open.area open.area open.area open.area water water vineyard 16

17 Results Step2 Repartition of variance between variables Plants Manag 6% Edaph 9% Topog 7% Land 2% Plants Leafhopper Spider Ground beetles Manag Topog Edaph Land

18 partial conclusions Step1 & Step2 n of mowing and n of herbicide applications are most important management variables; The slope of the field significantly affected the taxa considered; Chemical properties and texture of soil affect the plant and arthropods communities; The presence of vegetated open area surrounding the vineyard significantly affected the taxa considered. 18

19 Axis 2 (6% var. expl.; p-value < 0.005) Results Step3 Plants Tot var. expl. 28% open.area Mowing Slope Herbic Axis 1 ( 11% var. expl.; p-value < 0.005) 19

20 Results Step3 Plants Leafhoppers Spiders Ground beetles Management Herbic Herbic Herbic Herbic Mowing Mowing Mowing Topographic Slope Slope Slope Slope Altitude Altitude Altitude Solar_rad Solar_rad Edaphic MO N N N Sand grass_layer grass_layer Sand NO3 Clay Landscape open.area open.area open.area open.area water water vineyard 20

21 partial conclusions Step3 n of mowing explains most of the variance of communities; n of herbicide applications is an important factor for beetles communities only; the slope of the field and the open area affect the communities to local and landscape scale; percentage of NO3 in the soil is important for plant communities only, whereas leafhoppers and beetles respond to % of total nitrogen. 21

22 Results Step4 To detect threshold values threshold value Variable units plant leafhopper spider beetle Herbicide [#/y] Mowing [#/y] Slope [degrees] altitude [m] MO [%] NO3 [kg/ha] Sand [%] Ntot [%] Grass-layer [%] open area [ha] water [m2]

23 Results Step5 To detect sites groups for Management GrB GrA Low Management pressure Leontodon hispidus ** Vicia sepium * Thalictrum minus * Agrostis capillaris * Silene dioica * Sedum maximum * High Management pressure Ranunculus repens * Hypochaeris radicata * Prunella vulgaris * Agrostis stolonifera * 23

24 Results Step5 To detect sites groups for Edaphic GrA nitrogen-poor Rorippa sylvestris * GrB nitrogen-rich Hordeum murinum ** Senecio vulgaris ** Sonchus oleraceum * GrC organic matter-rich Silene vulgaris ** Silene pratensis * Paucedanum oreoselinum * Salvia preatensis * Leontodon hispidus * Echium vulgare * 24

25 partial conclusions Step4 & Step5 The threshold for mowing is 3 - for three taxa out 4; The plants and leafhoppers identify a threshold = 0 for the number of herbicide applications; The plants identify a threshold of 5% for MO and 30 Kg/ha for NO3, the arthropods identify a value of about 0.33 for Ntot; overall, I select 11 indicator species for high management pressure and 18 for low. I select 25 indicators for nutrient rich vineyards and 11 for nutrient poor vineyards. 25

26 Conclusions In the biodiversity monitoring programmes for grant subsidies to vine-growers, a list of effective bio-indicators should be based on: many species representing various taxa and trophic levels; a sound quantitative database from the focal region; species that clearly represent the environment health. 26

27 Thank you for your attention Acknowledgements FOEN, Agricultural agency Fondo Cotti 27