This document discusses habitat management techniques for increasing agroecosystem services. Modern farming practices have reduced habitat availability for beneficial arthropods through disturbances and pesticide use. The introduction of flowering strips provides complementary resources to fulfill arthropod lifecycles and increases the abundance of natural enemies and pollinators. Field trials in Italy found that flowering strips significantly increased populations of beneficial insects like predators and parasitoids. Yields of tomatoes were also higher in fields with flowering strips, though reductions in pest damage were inconsistent, possibly because pests could also utilize strip resources. Proper habitat management through flowering strips can thus augment natural pest control and pollination services in crops.

1. Habitat management for realising multiple
agroecosystem services
Mario V. Balzan
Institute of Applied Science, Malta College of Arts, Science &
Technology (MCAST), Malta.
mario.balzan@mcast.edu.mt

2. Arable Cropping Systems
● characterised by spatio-temporal
discontinuity;
● frequent ecological disturbances:
tillage, mechanical and chemical
weed control, insect and
diseases control measures and
crop burial after harvest;
● pesticide use has several direct
and indirect adversary effects on
agricultural biodiversity;
● agricultural landscapes
simplification associated with
modern farming practices Processing tomato fields.

3. Habitat Management
● The aforementioned stressors reduce habitat availability
for arthropod communities that provide important
ecosystem services, including pollination and natural pest
control.
● Habitat defined as the co-occurence of complementary
resources (e.g. nectar and pollen, larval hosts, nesting
sites, etc.), accessible to individuals at a location, that fulfil
the needs of organisms throughout their lifecycles (Dennis
& Shreeve 1996; Dennis et al. 2003).

4. Habitat Management
● Several natural enemy groups make use of non-pest plant-
derived resources (Wackers and van Rijn, 2012);
● Natural enemy enhancement, herbivore suppression and
crop damage suppression were all higher in crops with
increased plant diversity (review by Letourneau et al.,
2011).
● Increased plant diversity has been shown to enhance the
abundance of bees and pollinators (Nicholls and Altieri,
2012).

5. Trial 1 ­ Functional diversity in flower strips (Pisa)
Cumulative increment of floral functional effect groups, in the sown
wildflower and actual flowering species mixture, with each experimental
level and as a function of species richness.
Balzan et al., 2014, Journal of Insect Conservation

6. Results
● Total of 12,459 arthropods collected in 2011;
● Introduced flowering strips significantly increased
abundance of several arthropod groups including several
natural enemies e.g. Carabidae, Araneae, Staphylinidae,
Anthocoridae, Parasitica (Hymenoptera);
● Idiosyncrasy in floral resources – arthropod relations
(assessed using Generalised Linear Mixed Models
(GLMM) for each group)

7. Balzan et al., 2014, Journal of Insect Conservation

8. L1
L3
L2
NMDS ordination plot using a Bray-Curtis dissimilarity matrix and showing arthropod
groups association to flower strip mixtures. Ellipses represent 95% confidence
intervals of point scores from the covariance matrix for each level, while letters
represent the centroid position for each level (L1=A; L2=B; L3=C)
Balzan et al., 2014, Journal of Insect Conservation

9. *
*
*
(a) (b)
Variation of (a) number of fruits produced and (b) dry biomass with flower strips.
Each experimental level indicates a different flower mixture, with increasing plant
functional group richness (median ± 95% confidence intervals).

10. Trial 2 - Pollination and Pest Control ES
● Research objective:
– To enhance the
conservation of insect
diversity in arable fields
whilst providing
pollination and pest
control ES.

11. Lepidopteran pests (Noctuidae, Gelechiidae) Sucking bugs
Arthropod pests of tomato

12. Preliminary results
● Sown strips provided habitat to
natural enemies of tomato pests
● Limited pest attack recorded
from the study area;
● No major reductions could be
deducted
Preliminary results indicate that sown
flowering strips increase the number of
tomatoes produced.
Pollination Pest Control

13. Conclusions
● Habitat management through the establishment of flowering
strips augments the abundance of natural enemies and
pollinators groups;
● Results indicate increased yield in experimental fields with
flowering strips;
● However, reduction in pest damage not always consistent,
which may be caused by the actual resource use by the pest.
– e.g. T. absoluta was able to utilise nectar resources from
most of the flowers provided in a greenhouse experiment
(Balzan and Wackers, 2013)