Broadening the scope of empirical studies to answer persistent questions in landscape-moderated effects on biodiversity and ecosystem functioning

Despite a developing understanding of how landscape level processes moderate biodiversity patterns and ecosystem functioning, key questions remain unresolved, therefore limiting our ability to manage for biodiversity conservation and ecosystem functioning at the most appropriate scales. These questions have remained unanswered because studies in agricultural landscapes generally over-emphasize alpha diversity within managed land uses, and are focused at scales that are irrelevant to species studied. We argue that the key to resolving unanswered questions in landscape-moderated effects on biodiversity and ecosystem functioning lies in establishing the distribution of available species and functions across the landscape and between land uses, and in understanding how this distribution of species varies with changing landscape context. We emphasize the need for studies that empirically test the mechanisms underpinning landscape-moderated effects on biodiversity and ecosystem function and link these with ecosystem service delivery. We facilitate this approach by outlining the empirical investigations that will lead to a better understanding of biodiversity patterns and ecosystem functioning at the landscape scale, and we highlight statistical approaches to support these different approaches to sampling. Our paper is divided in four sections: (A) we identify where and why gaps exist in our mechanistic understanding of landscape level processes, by reviewing current hypotheses; (B) we outline why, and how, landscape level research would benefit from shifting the focus to the distribution and partitioning of species and functions within a landscape; (C) we outline why, and how, larger scale processes, such as dispersal and meta-population dynamics need to be addressed in a more interactive fashion; and finally, (D) we round out by highlighting the experimental settings where landscape effects most urgently need testing.