Contents lists available at ScienceDirect Agriculture, Ecosystems and Environment journal homepage: www.elsevier.com/locate/agee Seed predation intensity and stability in agro-ecosystems: Role of predator diversity and soil disturbance Francesco Lami a, *, Francesco Boscutti b , Roberta Masin a , Maurizia Sigura b , Lorenzo Marini a a DAFNAE, University of Padova, Viale dell’Università 16, 35020, Legnaro, Padova, Italy b Di4A-Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze 208, 33100, Udine, Italy ARTICLEINFO Keywords: Carabid beetles Conservation tillage Functional diversity Post-dispersal seed predation Spatial stability Weed control ABSTRACT Seed predation by arthropods can contribute in regulating population and community dynamics of weeds. While the role of insects, and especially ground beetles (Coleoptera: Carabidae) as seed predators in crop fields is well studied, the drivers of predation stability and the relationships between species diversity and predation are less understood. The aims of the study were: 1) to unveil the direct relationships between predator community diversity and seed predation intensity and stability, and 2) to test the effects of soil disturbance (conventional vs. conservation tillage) and distance from field margin on seed predator communities and predation. Seed pre- dation was measured using seed cards, and predator communities were sampled using pitfall traps over two years. Granivorous ground beetles, ants and crickets were the most abundant seed predators in both conven- tional and conservation tillage fields. Abundant and diverse predator communities were beneficial to predation intensity and stability. However, in communities dominated by large predators, an increase in number of species was related to a partial suppression of seed predation. Soil disturbance per se did not influence the overall predator community composition and predation, but it modified their spatial patterns within the fields. At the margins of conventional tillage fields, predation was lower and patchier than at the margins of conservation tillage fields. However, predation increased more steeply towards the center of conventional tillage field. Our results could find applications in sustainable weed management through biological control, as well as in better understanding the role of functional diversity in regulating ecosystem services. 1. Introduction Conservation agriculture (based on minimum soil disturbance, perma- nent soil plant cover and crop rotation) has often been proposed as an effective alternative to tillage worldwide (Holland, 2004). Fields managed under conservation agriculture have been proven to generally harbor higher biodiversity and to provide pivotal ecosystem services such as re- duced soil erosion, higher fertility, and carbon sequestration (Tamburini et al., 2016a). However, conservation tillage fields are also expected to be more prone to weed infestation (Chauhan et al., 2012). Given that weeds are one of the most important biotic factors limiting yields worldwide in both conservation and conventional tillage systems (Oerke, 2006), and that herbicide use causes pollution and the evolution of resistant populations (Annett et al., 2014; Jasieniuk and De, 2013), there is great interest in finding complementary, more sustainable strategies of weed control. Seed predation has been shown to play an important role in regulating population and community dynamics of weeds (Hulme, 1998; Larios et al., 2017). There is a wide variety of animals that act as seed predators including birds, rodents, arthropods and gastropods (O’Rourke et al., 2006). Ground beetles (Coleoptera: Carabidae), in particular, are among the most abundant and important invertebrate seed predators in agroeco- systems (Honek et al., 2003). While ecosystem services provided by insects are generally under-investigated and based on proxies rather than on the quantification of the service itself (Noriega et al., 2017), the general role of ground beetles as seed predators in crop fields is relatively well studied (Petit et al., 2014). The factors affecting predation stability across time and space, however, are less understood (Kolb et al., 2007; Labruyere et al., 2018). Soil invertebrates, including ground beetle seed predators (Blubaugh and Kaplan, 2015; Shearin et al., 2007) can suffer direct mor- tality from the mechanical actions of tillage practices or indirect effects through habitat modification, exposure to predators and reduced prey availability (Hance, 2002; Holland, 2004; Holland and Luff, 2000). Ad- ditionally, it is known that different ground beetle species can present clumped spatial distributions even within the same field (Holland et al., 2005; Thomas et al., 2001), with potential repercussions on the spatial stability of ecosystem services linked to these insects, including seed https://doi.org/10.1016/j.agee.2019.106720 Received 25 March 2019; Received in revised form 10 October 2019; Accepted 17 October 2019 ⁎ Corresponding author. E-mail address: francesco.lami@phd.unipd.it (F. Lami). Agriculture, Ecosystems and Environment 288 (2020) 106720 0167-8809/ © 2019 Elsevier B.V. All rights reserved. T