On-farm habitat restoration counters biotic homogenization in intensively managed agriculture

In-Field Habitat Management to Optimize Pest Control of Novel Soil Communities in Agroecosystems

The challenge of managing agroecosystems on a landscape scale and the novel structure of soil communities in agroecosystems both provide reason to focus on in-field management practices, including cover crop adoption, reduced tillage, and judicial pesticide use, to promote soil community diversity. Belowground and epigeal arthropods, especially exotic generalist predators, play a significant role in controlling insect pests, weeds, and pathogens in agroecosystems. However, the preventative pest management tactics that dominate field-crop production in the United States do not promote biological control. In this review, we argue that by reducing disturbance, mitigating the effects of necessary field activities, and controlling pests within an Integrated Pest Management framework, farmers can facilitate the diversity and activity of native and exotic arthropod predators.

Crop pollination services at the landscape scale

Managed and wild pollinators of different functional groups can provide pollination services in agricultural landscapes. These pollinators differ in their resource requirements and response to the amount and arrangement of different habitat types, that is, landscape composition and configuration. Most current approaches to test landscape effects on pollinators and pollination services are either applied to central individual crop fields or other landscape elements but rarely consider that pollinators depend on and make use of multiple habitat elements in an entire landscape. To capture these complex spatial and temporal interactions between different pollinators and habitat elements at the landscape scale, we propose to apply a combination of experimental and observational approaches across multiple habitat types and seasons.

Pollination Reservoirs in Lowbush Blueberry (Ericales: Ericaceae)

Pollinator-dependent agriculture heavily relies upon a single pollinator-the honey bee. To diversify pollination strategies, growers are turning to alternatives. Densely planted reservoirs of pollen- and nectar-rich flowers (pollination reservoirs, hereafter "PRs") may improve pollination services provided by wild bees. Our focal agroecosystem, lowbush blueberry (Vaccinium angustifolium Aiton), exists in a simple landscape uniquely positioned to benefit from PRs. First, we contrast bee visitation rates and use of three types of PR. We consider the effects of PRs on wild bee diversity and the composition of bumble bee pollen loads. We contrast field-level crop pollination services between PRs and controls four years postestablishment. Last, we calculate the time to pay for PR investment. Social bees preferentially used clover plantings; solitary bees preferentially used wildflower plantings. On average, bumble bee pollen loads in treatment fields contained 37% PR pollen. PRs significantly increased visitation rates to the crop in year 4, and exerted a marginally significant positive influence on fruit set. The annualized costs of PRs were covered by the fourth year using the measured increase in pollination services. Our findings provide evidence of the positive impact of PRs on crop pollination services.

Ecological intensification to mitigate impacts of conventional intensive land use on pollinators and pollination

Worldwide, human appropriation of ecosystems is disrupting plant–pollinator communities and pollination function through habitat conversion and landscape homogenisation. Conversion to agriculture is destroying and degrading semi‐natural ecosystems while conventional land‐use intensification (e.g. industrial management of large‐scale monocultures with high chemical inputs) homogenises landscape structure and quality. Together, these anthropogenic processes reduce the connectivity of populations and erode floral and nesting resources to undermine pollinator abundance and diversity, and ultimately pollination services. Ecological intensification of agriculture represents a strategic alternative to ameliorate these drivers of pollinator decline while supporting sustainable food production, by promoting biodiversity beneficial to agricultural production through management practices such as intercropping, crop rotations, farm‐level diversification and reduced agrochemical use. We critically evaluate its potential to address and reverse the land use and management trends currently degrading pollinator communities and potentially causing widespread pollination deficits. We find that many of the practices that constitute ecological intensification can contribute to mitigating the drivers of pollinator decline. Our findings support ecological intensification as a solution to pollinator declines, and we discuss ways to promote it in agricultural policy and practice.

Homogenizing and diversifying effects of intensive agricultural land-use on plant species beta diversity in Central Europe - A call to adapt our conservation measures

The prevention of biodiversity loss in agricultural landscapes to protect ecosystem stability and functions is of major importance to stabilize overall diversity. Intense agriculture leads to a loss in species richness and homogenization of species pools, but the processes behind are poorly understood due to a lack of systematic case studies: The specific impacts by agriculture in contrast to other land-use creating open habitat are not studied as such landscapes hardly exist in temperate regions. Applying systematic grids, we compared the plant species distribution at the landscape scale between an active military training areas in Europe and an adjacent rather intensively used agricultural landscape. As the study areas differ mainly in the type of disturbance regime (agricultural vs. non-agricultural), differences in species pattern can be traced back more or less directly to the management. Species trait analyses and multiple measures of beta diversity were applied to differentiate between species similarities between plots, distance-decay, or nestedness. Contrary to our expectation, overall beta diversity in the agricultural area was not reduced but increased under agricultural. This was probably the result of species nestedness due to fragmentation. The natural process of increasing dissimilarity with distance (distance-decay) was suppressed by intense agricultural land-use, generalist and long-distance dispersers gained importance, while rare species lost continuity. There are two independent processes that need to be addressed separately to halt biodiversity loss in agricultural land. There is a need to conserve semi-natural open habitat patches of diverse size to favor poor dispersers and specialist species. At the same time, we stress the importance of mediating biotic homogenization caused by the decrease of distance-decay: The spread of long-distance dispersers in agricultural fields may be acceptable, however, optimized fertilizer input and erosion control are needed to stop the homogenization of environmental gradients due to nitrogen input into semi-natural habitat.