Persistence of Seed Dispersal in Agroecosystems: Effects of Landscape Modification and Intensive Soil Management Practices in Avian Frugivores, Frugivory and Seed Deposition in Olive Croplands

Abstract

Farming impacts animal-mediated seed dispersal through mechanisms operating on at least two spatial scales. First, at the landscape scale, through habitat loss and land conversion to agriculture/livestock grazing, and second, at the farm scale, via a local intensification of agricultural practices. These two scales of farming impact seed dispersal function but have rarely been integrated. In particular, studies evaluating the effect of agriculture on the seed dispersal function of frugivorous birds in Mediterranean ecosystems are lacking. This study evaluates the role of landscape transformation, from fruit-rich woodland habitats to olive grove landscapes, together with local intensive practices of soil management on the persistence of the seed dispersal function for Mediterranean fleshy-fruited plants in olive landscapes of south Spain. We used bird censuses, mist-nets, and seed traps to characterize avian frugivore assemblages, frugivory, and seed deposition in the seminatural woodland habitat (SNWH) patches and olive fields of 40 olives farms spanning 20 localities distributed across the whole range of olive cultivation in Andalusia (southern Spain). We found that despite the remarkable dispersal function of olive grove landscapes, avian frugivore abundance and diversity, frugivory, and seed arrival decreased in olive fields compared to SNWH patches. Likewise, SNWH cover loss and/or olive growing expansion decreased avian frugivory and seed arrival. Interestingly, the habitat effects in the olive farms often depended on the landscape context. In particular, less diverse fruit-eating bird assemblages pooled in SNWH patches as olive grove cover increased or SNWH decreased in the landscape, while remaining relatively invariant in the olive fields. Finally, compared to conventional intensive agriculture, low-intensity management increased frugivory and seed deposition. We conclude that olive fields are less permeable to frugivores than expected due to the agroforest-like nature of these landscapes and that the presence of SNWH patches is crucial for the maintenance of frugivory and seed dispersal in agricultural landscapes. These results evidence that woodland habitat loss by olive expansion and intensive practices seriously threaten the dispersal service in olive-dominated landscapes. Maintenance, restoration, and promotion of woodland patches should be prioritized for the conservation of seed dispersal service and for enhancing the functional connectivity in human-shaped olive landscapes.

Rapid assessment of post-dispersal seed removal in an agricultural landscape of semi-arid West Africa

“…This study sheds light on the in uence of agroecosystems and predators on post-dispersal seed removal patterns in a semi-arid savanna landscape. Our ndings con rm that the conversion of natural habitats such as woodlands to agriculture negatively affects post-dispersal services (Escobar et al 2020;Rey et al 2021). In this study, the seed removal rate was signi cantly higher in the woodland habitat than in the agricultural habitats.…”

Spiders indicate delivery of an agri-environment scheme at multiple diversity levels

“…The multivariate dispersion was higher among BPA hedges than among production fields, reflecting both different environmental conditions of the BPA hedges and a possible difference of management within them. Investigations have emphasized the important role of hedgerows as conservation element for biodiversity in the agricultural landscape (e.g., Forman and Baudry, 1984;Rey et al, 2021) and also for biocontrol purposes (e.g., Marino and Landis, 1996;Kolb et al, 2020;Martínez-Núñez et al, 2021).…”

Driving the Ecological Transition of Agriculture through Voluntary Certification of Environmental Impacts: An Exploratory Literature Review on the Olive-Oil Sector

“…It issues two certificates: the first, "In the transition to Olivares Vivos", which guarantees the correct execution of the action plan, and the second, "Olivares Vivos", which certifies that the plan has been implemented and that the initially established biodiversity recovery objectives have been achieved. This is a new certification on the market, which comes after several years of intense research in the field of ecology and environmental restoration [170][171][172][173], as well as market studies aimed at guaranteeing its commercial viability. Another differential fact of this certification is that it arises from a conservation project integrated by different nonprofit organizations, initially launched by SEO/BirdLife, the University of Jaén, the Spanish National Research Council, and the Provincial Council of Jaén, which developed the certification in Spain.…”