Habitat complexity in organic olive orchards modulates the abundance of natural enemies but not the attraction to plant species

Abstract

Semi-natural habitat complexity and organic management could affect the abundance and diversity of natural enemies and pollinators in olive orchards. Nonetheless, in such agroecosystems the effect of plant structure, plant richness, and plant attraction on the arthropod fauna has been poorly documented. Here we evaluate the influence of those effects jointly as an expression of arthropod abundance and richness in olive trees, ground cover, and adjacent vegetation within organic olive orchards. For this, we used generalized linear models and non-metric multidimensional scaling (NMDS) integrating generalized additive models. Our results suggest that natural enemies and pollinators are mainly attracted to A. radiatus, D. catholica, and L. longirrostris within ground cover and G. cinerea speciosa, Q. rotundifolia, R. officinalis, T. zygis gracilis, and U. parviflorus within adjacent vegetation. Accordingly, habitat complexity showed a positive relationship with the abundance of key families of natural enemies and pollinators but not with the number of taxa. NMDS showed that plant richness and plant arrangement and scattering affected the key families differently, suggesting that each key family responds to their individual needs for plant resources but forming groups modulated by complexity. This pattern was especially seeing in predators and omnivores. Our findings support that the higher the plant richness and structure of a semi natural-habitat within an olive orchard, the higher the abundance and richness of a given arthropod community (a pattern found in natural ecosystems). The information presented here can be used by producers and technicians to increase the presence and abundance of natural enemies and pollinators within organic olive orchards, and thus improve the ecosystem services provided by semi-natural habitats.

Ground cover vegetation promotes biological control and yield in pear orchards

“…Natural enemies like predatory spiders or ladybirds might migrate from the ground cover vegetation into the pear tree canopies to prey canopy herbivores. A similar migration process has also been observed in citrus orchards with cover vegetation (Silva et al., 2010), in olive orchards with ground cover and adjacent vegetation (Alvarez, Jiménez‐Muñoz, et al., 2021; Alvarez, Morente, Campos, et al., 2019; Alvarez, Morente, Oi, et al., 2019; Alvarez, Morente, et al., 2021), in peach orchards with white clover vegetation (Wan, Gu, et al., 2014; Wan, Ji, et al., 2014), in strawberry fields surrounded by spontaneous vegetation (Jacobsen et al., 2019), in rice fields surrounded by border crops (Wan, Cai, et al., 2018) or within soybean field habitat with manipulated red clover (Blubaugh et al., 2016).…”

“…The adoption of ground cover vegetation in orchard has shown to be a potential way to promote biological pest control by natural enemies and associated ecosystem services (Alvarez, Morente, et al., 2021; Aparicio et al., 2021; Blaise et al., 2021; Mateos‐Fierro et al., 2021). Furthermore, its role on functional biodiversity (e.g.…”

“…Similarly, culturing engineering of ground cover vegetation is also a valuable strategy for promoting agricultural biodiversity (Ricci et al., 2019; Riordan et al., 2020) and biocontrol services. The use of different ground cover vegetations in place of bare soil has been promoted and adopted with positive results in many orchard systems, such as olive (Alvarez, Morente, Campos, et al., 2019; Alvarez, Jiménez‐Muñoz, et al., 2021; Alvarez, Morente, et al., 2021; Alvarez, Morente, Oi, et al., 2019), cherry (Mateos‐Fierro et al., 2021), peach (Aparicio et al., 2021; Musacchi et al., 2021; Wan, Gu, et al., 2014; Wan, Ji, et al., 2014, 2018), apple (Santos et al., 2018), vineyards (Blaise et al., 2021; Geldenhuys et al., 2021; Judt et al., 2019), coffee and tea plantations (Chen et al., 2019; Jimenez‐Soto et al., 2019). In China, ground cover vegetation of white clover ( Trifolium repens ) and hairy vetch ( Vicia villosa ) have been adopted in orchards since the 1990s to promote biological control of insects and to improve soil fertility (Wan, Gu, et al., 2014; Wan, Ji, et al., 2014; Yi et al., 2010).…”

Ground cover presence in organic olive orchards affects the interaction of natural enemies against Prays oleae, promoting an effective egg predation

“…This was reflected in the composition and abundance of families of natural enemies. Both local and large-scale factors can affect the abundance of natural enemies and pests in olive orchards, such as less pesticide application or microclimate conditions and landscape diversity or patch size, respectively (Boccaccio and Petacchi, 2009;Rodríguez et al, 2009;Ortega and Pascual, 2014;Villa et al, 2016a;2020;Morente et al, 2018;Álvarez et al, 2019a;2019b;2021). This may explain why the structure of the arthropod community tended not to differ in our study.…”