Habitat restoration promotes pollinator persistence and colonization in intensively managed agriculture.

Widespread evidence of pollinator declines has led to policies supporting habitat restoration including in agricultural landscapes. Yet, little is yet known about the effectiveness of these restoration techniques for promoting stable populations and communities of pollinators, especially in intensively managed agricultural landscapes. Introducing floral resources, such as flowering hedgerows, to enhance intensively cultivated agricultural landscapes is known to increase the abundances of native insect pollinators in and around restored areas. Whether this is a result of local short-term concentration at flowers or indicative of true increases in the persistence and species richness of these communities remains unclear. It is also unknown whether this practice supports species of conservation concern (e.g., those with more specialized dietary requirements). Analyzing occupancies of native bees and syrphid flies from 330 surveys across 15 sites over eight years, we found that hedgerow restoration promotes rates of between-season persistence and colonization as compared with unrestored field edges. Enhanced persistence and colonization, in turn, led to the formation of more species-rich communities. We also find that hedgerows benefit floral resource specialists more than generalists, emphasizing the value of this restoration technique for conservation in agricultural landscapes.

[1]  F. Gilbert,et al.  The Natural History of Hoverflies , 2011 .

[2]  N. Blüthgen,et al.  Measuring specialization in species interaction networks , 2006, BMC Ecology.

[3]  Michel Loreau,et al.  Biodiversity, Ecosystem Functioning, and Human Wellbeing: An Ecological and Economic Perspective , 2009 .

[4]  Jeffrey D. Lozier,et al.  Patterns of widespread decline in North American bumble bees , 2011, Proceedings of the National Academy of Sciences.

[5]  Martyn Plummer,et al.  JAGS: A program for analysis of Bayesian graphical models using Gibbs sampling , 2003 .

[6]  C. Kearns.  North American Dipteran Pollinators: Assessing Their Value and Conservation Status , 2001 .

[7]  A. Newton,et al.  Enhancement of Biodiversity and Ecosystem Services by Ecological Restoration: A Meta-Analysis , 2009, Science.

[8]  C. Kremen,et al.  Hedgerow restoration promotes pollinator populations and exports native bees to adjacent fields. , 2013, Ecological applications : a publication of the Ecological Society of America.

[9]  Claire Kremen,et al.  EDITOR'S CHOICE: Small‐scale restoration in intensive agricultural landscapes supports more specialized and less mobile pollinator species , 2015 .

[10]  J. Andrew Royle,et al.  Estimating species richness and accumulation by modeling species occurrence and detectability. , 2006, Ecology.

[11]  Katherine N. Suding,et al.  Restoration through reassembly: plant traits and invasion resistance. , 2008, Trends in ecology & evolution.

[12]  C. Kremen,et al.  Bee Preference for Native versus Exotic Plants in Restored Agricultural Hedgerows , 2013 .

[13]  N. Carreck,et al.  Honey bee colony losses , 2010 .

[14]  S. Nilsson,et al.  High population variability and source-sink dynamics in a solitary bee species. , 2013, Ecology.

[15]  D. MacKenzie.  Occupancy Estimation and Modeling: Inferring Patterns and Dynamics of Species Occurrence , 2005 .

[16]  A. Klein,et al.  Understanding the role of species richness for crop pollination services , 2009 .

[17]  F. Herzog,et al.  Mixed biodiversity benefits of agri-environment schemes in five European countries. , 2006, Ecology letters.

[18]  D. Kleijn,et al.  At what spatial scale do high-quality habitats enhance the diversity of forbs and pollinators in intensively farmed landscapes? , 2007 .

[19]  J. C. Marlin,et al.  Plant-Pollinator Interactions over 120 Years: Loss of Species, Co-Occurrence, and Function , 2013, Science.

[20]  J. Ollerton,et al.  How many flowering plants are pollinated by animals , 2011 .

[21]  E. Fleishman,et al.  An empirical evaluation of the area and isolation paradigm of metapopulation dynamics , 2007 .

[22]  A. Klein,et al.  Bee diversity and plant-pollinator interactions in fragmented landscapes , 2006 .

[23]  D. Tilman,et al.  Diversity‐Stability Relationships: Statistical Inevitability or Ecological Consequence? , 1998, The American Naturalist.

[24]  Myles H. M. Menz,et al.  Reconnecting plants and pollinators: challenges in the restoration of pollination mutualisms. , 2011, Trends in plant science.

[25]  A. P. Schaffers,et al.  Parallel Declines in Pollinators and Insect-Pollinated Plants in Britain and the Netherlands , 2006, Science.

[26]  Quentin Groom,et al.  Species richness declines and biotic homogenisation have slowed down for NW-European pollinators and plants , 2013, Ecology letters.

[27]  R. Isaacs,et al.  Stability of pollination services decreases with isolation from natural areas despite honey bee visits. , 2011, Ecology letters.

[28]  John H. Lawton,et al.  Redundancy in Ecosystems , 1994 .

[29]  I. Bartomeus,et al.  Biodiversity ensures plant-pollinator phenological synchrony against climate change. , 2013, Ecology letters.

[30]  A F G Bourke,et al.  Bumble bee species' responses to a targeted conservation measure depend on landscape context and habitat quality. , 2011, Ecological applications : a publication of the Ecological Society of America.

[31]  R. Winfree.  The conservation and restoration of wild bees , 2010, Annals of the New York Academy of Sciences.

[32]  Teja Tscharntke,et al.  Landscape-moderated biodiversity effects of agri-environmental management: a meta-analysis , 2011, Proceedings of the Royal Society B: Biological Sciences.

[33]  J. Andrew Royle,et al.  A Bayesian state-space formulation of dynamic occupancy models. , 2007, Ecology.

[34]  Aaron M. Ellison,et al.  Modern Methods of Estimating Biodiversity from Presence-Absence Surveys , 2011 .

[35]  P. D. Hurd,et al.  Principal sunflower bees of North America with emphasis on the Southwestern United States (Hymenoptera, Apoidea) , 1980 .

[36]  W. Meek,et al.  Management to enhance pollen and nectar resources for bumblebees and butterflies within intensively farmed landscapes , 2011, Journal of Insect Conservation.

[37]  Alana L. Burley,et al.  A global quantitative synthesis of local and landscape effects on wild bee pollinators in agroecosystems. , 2013, Ecology letters.

[38]  M. Vighi,et al.  The impact of an insecticide on insect flower visitation and pollination in an agricultural landscape , 2010 .

[39]  Nico Blüthgen,et al.  Land-use impacts on plant-pollinator networks: interaction strength and specialization predict pollinator declines. , 2014, Ecology.

[40]  J. Cane,et al.  Spatial predictability and resource specialization of bees (Hymenoptera: Apoidea) at a superabundant, widespread resource , 1999 .

[41]  Breno M. Freitas,et al.  Wild Pollinators Enhance Fruit Set of Crops Regardless of Honey Bee Abundance , 2013, Science.

[42]  P. Reich,et al.  High plant diversity is needed to maintain ecosystem services , 2011, Nature.

[43]  J. Biesmeijer,et al.  Global pollinator declines: trends, impacts and drivers. , 2010, Trends in ecology & evolution.

[44]  P. D. Hurd,et al.  Ecology of the squash and gourd bee, Peponapis pruinosa, on cultivated cucurbits in California (Hymenoptera: Apoidea) , 1974 .

[45]  Teja Tscharntke,et al.  Fruit set of highland coffee increases with the diversity of pollinating bees , 2003, Proceedings of the Royal Society of London. Series B: Biological Sciences.