Citation: Pardee, G.L.; Ballare, K.M.; Neff, J.L.; Do, L.Q.; Ojeda, D.; Bienenstock, E.J.; Brosi, B.J.; Grubesic, T.H.; Miller,J.A.; Tong, D.; et al. Local and Landscape Factors Influence Plant-Pollinator Networks and Bee Foraging Behavior across an Urban Corridor. Land 2023, 12, 362. https:// doi.org/10.3390/land12020362 Academic Editors: María Fe Schmitz and Cecilia Arnaiz Schmitz Received: 8 December 2022 Revised: 12 January 2023 Accepted: 16 January 2023 Published: 29 January 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). land Article Local and Landscape Factors Influence Plant-Pollinator Networks and Bee Foraging Behavior across an Urban Corridor Gabriella L. Pardee 1, * , Kimberly M. Ballare 1,2 , John L. Neff 3 , Lauren Q. Do 1 , DianaJoyce Ojeda 1 , Elisa J. Bienenstock 4,† , Berry J. Brosi 5,† , Tony H. Grubesic 6,† , Jennifer A. Miller 7,† , Daoqin Tong 8,† and Shalene Jha 1,9 1 Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA 2 Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA 95064, USA 3 Central Texas Melittological Institute, Austin, TX 78731, USA 4 Watts School of Public Service and Community Solutions, Arizona State University, Tempe, AZ 85281, USA 5 Department of Biology, University of Washington, Seattle, WA 98195, USA 6 Center for Geospatial Sciences, University of California Riverside, Riverside, CA 92521, USA 7 Department of Geography and the Environment, University of Texas at Austin, Austin, TX 78712, USA 8 School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, AZ 85281, USA 9 Lady Bird Johnson Wildflower Center, Austin, TX 78739, USA * Correspondence: gabriellapardee@gmail.com † These authors contributed equally to this work. Abstract: Given widespread concerns over human-mediated bee declines in abundance and species richness, conservation efforts are increasingly focused on maintaining natural habitats to support bee diversity in otherwise resource-poor environments. However, natural habitat patches can vary in composition, impacting landscape-level heterogeneity and affecting plant-pollinator interactions. Plant-pollinator networks, especially those based on pollen loads, can provide valuable insight into mutualistic relationships, such as revealing the degree of pollination specialization in a community; yet, local and landscape drivers of these network indices remain understudied within urbanizing landscapes. Beyond networks, analyzing pollen collection can reveal key information about species- level pollen preferences, providing plant restoration information for urban ecosystems. Through bee collection, vegetation surveys, and pollen load identification across ~350 km of urban habitat, we studied the impact of local and landscape-level management on plant-pollinator networks. We also quantified pollinator preferences for plants within urban grasslands. Bees exhibited higher foraging specialization with increasing habitat heterogeneity and visited fewer flowering species (decreased generality) with increasing semi-natural habitat cover. We also found strong pollinator species- specific flower foraging preferences, particularly for Asteraceae plants. We posit that maintaining native forbs and supporting landscape-level natural habitat cover and heterogeneity can provide pollinators with critical food resources across urbanizing ecosystems. Keywords: bee communities; pollination; pollinator generality; pollen preference; semi-natural habitat; specialization 1. Introduction The urban-to-rural interface has long been shown to drive changes in animal commu- nity composition via shifts in food and nesting resources, alteration in biotic and abiotic factors, and the impediment of an organism’s ability to disperse into hospitable habitat [1,2]. Despite this fact, researchers have only begun examining how changes in habitat com- position affect mutualistic relationships across human-modified landscapes [3,4]. This effort is complicated because natural habitats within urban areas are often highly het- erogenous and thus vary in their degree of quality and connectivity, which can directly Land 2023, 12, 362. https://doi.org/10.3390/land12020362 https://www.mdpi.com/journal/land