A Mediterranean silent spring? The effects of olive farming intensification on breeding bird communities

Morgado, Rui; Santana, Joana; Porto, Miguel; Sánchez-Oliver, Juan S.; Reino, Luís; Herrera, José Manuel Palma; Rego, Francisco; Beja, Pedro; Moreira, Francisco

doi:10.1016/j.agee.2019.106694

Cited by 47 publications

(37 citation statements)

References 58 publications

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“…However, the impact of expansion on bird diversity and composition must be assessed. A landscape monitoring approach (at a determined time step), considering (a) the cover of oases and olive orchards and (b) cover of habitats of their surroundings (Morgado et al, 2020; Rey et al, 2019) must be performed to know how bird diversity will be shaped in the coming years. The habitat conditions within orchards and oases are also of great importance.…”

Section: Conclusion Recommendations and Perspectivesmentioning

confidence: 99%

The effect of microhabitat features, anthropogenic pressure and spatial structure on bird diversity in southern Tunisian agroecosystems

Hamza

Hanane²

2021

Annals of Applied Biology

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In southern Tunisia, oases and olive orchards are the two main agroecosystems, hence the importance of investigating their value for native fauna. Using generalised linear mixed models, we assessed the relative value of oases and olive plantations over the wintering and the breeding periods by comparing their avifauna diversity using the Shannon diversity index. We also used data on a series of microhabitat features, anthropogenic pressure and spatial parameters to identify the best predictors of bird diversity. In total, 32 species belonging to 18 families were recorded. Sedentary birds accounted for 47% of the counts. Our results showed that bird diversity depends on habitat type, being higher in oases than in olive plantations, but not on the season as no difference was recorded during the two periods of wintering and breeding. The assessment of the effects of microhabitat features, anthropogenic pressure and spatial structure revealed that bird diversity was positively influenced by the cover of trees in oases and olive orchards, negatively affected by distance to edge and that to the paved road in the olive orchards and spatially structured in both agroecosystems. Variation partitioning analysis revealed that the pure effect of microhabitat features (tree cover) was important in explaining the bird diversity both in oases and olive orchards. The identification of factors affecting bird diversity is of great importance for the efficient management of these agroecosystems. Special attention should be paid to keeping a good tree cover. This cannot be performed without: (a) increasing irrigation frequency, (b) adequate tree maintenance (pruning) and (c) reduction of pesticide application. Also, the synergy among owners, farmers, managers and researchers is recommended for the conservation of bird diversity in this North African arid agricultural region.

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Section: Conclusion Recommendations and Perspectivesmentioning

confidence: 99%

The effect of microhabitat features, anthropogenic pressure and spatial structure on bird diversity in southern Tunisian agroecosystems

Hamza

Hanane²

2021

Annals of Applied Biology

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“…Super‐intensive orchards have expanded more recently, involving very high densities (1,000–2,500 trees/ha) of highly productive dwarf trees, planted in a hedgerow‐like pattern, with drip irrigation, heavy mechanisation and major use of agrochemicals (Connor et al., 2014; Tous et al., 2010). Intensification has increased productivity from <2.5 tonnes/ha in traditional, through 3–10 tonnes/ha in intensive, to 8–11 tonnes/ha in super‐intensive orchards (Connor et al., 2014; IOC, 2015; Silveira et al., 2018), but concerns have been raised on the ecological sustainability of these changes (Beaufoy, 2001; Moreira et al., 2019), mainly due to strongly negative biodiversity impacts (Carpio et al., 2016; Herrera et al., 2015; Morgado et al., 2020; Solomou & Sfougaris, 2011, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, variations in ripening phenology and harvest timing across cultivars and locations create a continuous supply of olives (Rey, 1995, 2011), which can be tracked in space and time by frugivorous birds (Tellería & Pérez‐Tris, 2003, Tellería et al., 2005). Intensification may thus bring benefits through increased olive availability in highly productive orchards (Muñoz‐Cobo & Montesino, 2003; Rey et al., 1996), though consequences may also be negative, particularly for non‐frugivorous species, due to structural orchard simplification (Costa et al., 2020; Morgado et al., 2020) and landscape homogenisation reducing the availability of alternative habitats (Santana et al., 2017). Moreover, intensification is associated with specialisation on a few cultivars (Tous et al., 2010), which together with landscape homogenisation through intensive olive farming may reduce temporal continuity in fruit availability (Rey, 2011).…”

Section: Introductionmentioning

confidence: 99%

Preserving wintering frugivorous birds in agro‐ecosystems under land use change: Lessons from intensive and super‐intensive olive orchards

Morgado

Pedroso

Porto

et al. 2021

Journal of Applied Ecology

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Fleshy fruit production is becoming more intensive worldwide, but how this affects frugivorous birds is poorly known. In the Mediterranean region, intensive and super‐intensive olive orchards are fast expanding, potentially affecting millions of wintering songbirds. Here, we test the idea that intensification may benefit frugivorous birds, at least locally, due to increased fruit availability, while negatively affecting the wider wintering bird community due to intensive management, structural simplification and landscape homogenisation. We estimated olive abundance and surveyed birds in early, mid‐ and late winter, at traditional, intensive and super‐intensive orchards in southern Portugal. We used Hierarchical Modelling of Species Communities to relate species richness, prevalence and abundance to management intensity, winter period, olive availability and landscape context, and evaluated the role of frugivory in modulating observed responses. Olive availability was much higher throughout the winter in more intensive than in traditional orchards, both in trees and on the ground. Frugivorous bird abundance was higher in more intensive orchards, and the most abundant frugivorous species (blackcap, song thrush, robin) were positively affected by olive availability and/or increasing landscape cover by olive orchards, while intensification level had relatively minor effects after accounting for other variables. Non‐frugivorous richness and abundance were higher in traditional orchards, and many non‐frugivorous species had lower prevalence in more intensive orchards or were negatively affected by landscapes dominated by olive cultivation. Synthesis and applications. While negatively affecting the wider bird community, our results suggest that olive farming intensification can contribute to sustaining large numbers of frugivorous birds in the Mediterranean region. As frugivorous birds are not seen as damaging by olive farmers, there is an opportunity to promote their conservation in intensive and super‐intensive orchards, which requires management to increase habitat heterogeneity, and to reduce risks such as mortality associated with mechanical harvest and contamination with pesticide residues. Overall, we recommend that efforts to manage farmland biodiversity should consider the impacts and conservation opportunities of fruit crop intensification.

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“…These declines in avian insectivore may suppose well above one order of magnitude in terms of energetic requirement by hectare of the whole insectivore guild between these habitats (Alcántara et al 1997b). Forest insectivores have also been shown to decline in olive orchards during the reproductive season as a function of agriculture intensification and/or landscape simplification (Castro-Caro, Barrio, & Tortosa, 2015; Morgado et al 2020). Such limited attractiveness of the olive tree matrix may be related with the current suboptimal (structural and feeding) conditions of this habitat where the management originates regular distribution of trees, absence of nesting cavities on tree trunks, short and reduced tree canopies, and lack of permanent scrub and/or herbaceous layers and their associated food resources.…”

Section: Discussionmentioning

confidence: 99%

Landscape drivers and effectiveness of pest control by insectivorous birds in a landscape-dominant woody crop

Martínez‐Núñez

Rey

Manzaneda

et al. 2020

Preprint

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Avian-mediated pest control is a significant ecosystem service with important economic implications. However, there is an overall paucity of experimental information about how landscape simplification affect its current level. Information on pest control by birds is missing in some permanent agroecosystems of worldwide importance, like olive orchards, that dominate vast areas in the Mediterranean region.We assess the effectiveness of insectivorous birds for controlling the two main pest insects in olive orchards and explore the effects of landscape complexity and distance to semi-natural patches on avian insectivore abundance and pest control. For this, we combine bird surveys with field experiments (branch exclusions and pest plasticine models) at the regional scale.Landscape heterogeneity increased the abundance and richness of insectivorous birds, which were also more abundant and diverse in semi-natural patches, compared to the farm olive matrix. Experiments evidenced that pest control by birds (measured as attack rates to plasticine models and pest damage) in the studied olive orchards is negligible, while pests were overall abundant and pest damage was high on most farms. This raises alarms about the status of avian pest control in this agroecosystem.Although landscape heterogeneity increased the abundance/richness of insectivorous birds, and favored some forest species, insectivorous bird abundance seems diluted in relation to prey availability in all landscapes. Thus, pest control by birds seems currently unsuccessful in olive orchards. Our results might be evidencing the loss of an ecosystem service due to a generalized massive decline of common and forest insectivorous birds.Key messageOlive orchards dominate extensive areas causing important landscape simplification.Insectivorous birds are more abundant in semi-natural patches within olive farms.Field experiments show a low impact of birds on olive pests and damage.Avian-mediated pest biocontrol seems diluted by limited suitable habitat for birds.Agri-environmental measures should focus on increasing landscape complexity.

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A Mediterranean silent spring? The effects of olive farming intensification on breeding bird communities

Cited by 47 publications

References 58 publications

The effect of microhabitat features, anthropogenic pressure and spatial structure on bird diversity in southern Tunisian agroecosystems

The effect of microhabitat features, anthropogenic pressure and spatial structure on bird diversity in southern Tunisian agroecosystems

Preserving wintering frugivorous birds in agro‐ecosystems under land use change: Lessons from intensive and super‐intensive olive orchards

Landscape drivers and effectiveness of pest control by insectivorous birds in a landscape-dominant woody crop

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