Similar results were found for tropical silvopastoral systems where the canopy cover and tree density were positively related with migratory bird flocks . In a comparison of different structural complexity, silvopastoral systems supported less diverse bird flocks than shade coffee in Colombia, but it is likely that shade coffee could support more bird species than open grazing lands . In Romania traditional silvopastoral systems of open oak woodland forest-pastures harbored more diverse and significantly different bird communities than modern high intensity managed open pastures .In Europe and North American prairie bird populations are declining due to agricultural intensification, resulting from the redusction of crop rotations, use of pesticides, and landscape simplification . In terms of habitat preferences, Skylarks were significantly positively influenced by legumes and set-aside, , a field with no or low agrochemical inputs, with weeds and wild flowers/grasses and low/ no tillage. In a meta-analysis, Van Buskirk and Willi found that set-aside in conventional agriculture increased bird richness and abundance ,container size for blueberries although set-aside parcels had greater benefit when surrounded by low intensity agriculture.
Floral diversity associated with diversified farms was shown to support a variety of grains and plant biomass for granivores bird species that use arable land as habitat , but depletion of these food resources via agriculture simplification and use of herbicides was found to negatively impact the granivorous populations . The interactions between bird habitat associations at the plot/local scale and landscape scale factors are relevant for implementing conservation strategies in arable lands, for instance, granivores species were prone local extinctions when arable land decreased in the landscape . Lowland rice fields are useful for bird conservation due to their similarity to natural wetlands . In Asia, the integration of wildlife with rice crops in wetland areas drives synergies between nutrient cycling and pest control. In the case of rice fields, ducks provide ecosystem services such as consumption of weed seeds, aquatic arthropods and rice pests, release of nutrients , and soil aeration, while rice fields provide ducks with shelter, nesting places, and food resources . In an exclusion experiment in rice flooded in winter in France, Brogi et al. reported that domesticated mallards mimicked wild populations of mallards by removing rice crop residues , independent of duck density, thereby accelerating the decomposition process post-harvest in the field. Long et al. compared duck-rice agroecological management and conventional rice farms and showed that duck-rice management effectively controlled insects , improved soil fertility and organic matter content, and reduced greenhouse gas emissions. In addition, Cagauan et al. recommended integration of water fern and fish in order to increase nutrient cycling within the duck-rice agroecosystem. The agroecological management of duck-rice farming is not only the reduced use of agrochemicals, but also improved yields and economic returns for low income farmers in Bangladesh .
To enhance conservation of waterbirds in rice fields, Elphick et al. suggested key agricultural management practices such as decreased use of pesticides and promoted field flooding. Harvest method , crop residue management , water management , agricultural management , and manipulation of edge fields and provision of landscape ponds and ditches are all practices that can benefit birds. Orchards provide vertical structures that can be used as habitat for birds. In central Chile Muñoz-Sáez et al. found that orchards as land cover at two spatial scales favored the abundance of five species including granivores, insectivores, and omnivores birds. Woody crops such as olive orchards can be beneficial for frugivorous birds, especially in winter . Castro-Caro et al. conducted a study relating bird richness with effects of ground cover in olive orchards within homogenous and heterogeneous landscapes. Their results showed that the effect of the herbaceous ground cover was beneficial for passerine birds , independent of the landscape category, suggesting that landscape structure did not play a significant role in determining bird species diversity in fruit orchards. Almond orchards were reported to host higher bird richness in Eastern Australia than in apple orchards, vineyards, and Eucalyptus woodlots, including the threatened Regent Parrot . Apple orchards can also be useful for birds species, in particular when managed organically, increasing the number of insectivores in comparison with conventional orchards or serve as habitat for woodpeckers . Orchards can be sources of tree-cavities that are relevant for secondary cavity nester birds .Agroforestry is proposed as a multifunctional system where agricultural and forestry productivity, ecosystem services and biodiversity conservation are simultaneously enhanced . In a meta-analysis Torralba et al. found that in agroforestry systems, biodiversity, soil fertility and soil erosion control is higher than in conventional agriculture and forestry.
Leakey highlights the functional role of trees in agroforestry: increasing soil fertility , increasing water infiltration and habitat for mycorrhizae, and providing habitat for wildlife, among others. Several studies have shown that multi-strata and diverse agroecosystems can provide habitat for many species, and increase conservation potential in these areas . In tropical ecosystems, cacao and coffee are usually grown in agroforestry systems, as these crops are naturally adapted to shade conditions. In a comparison, between shade and sun coffee, Johnson et al. found higher diversity and abundance of insectivorous and resident birds in shade coffee than in sun coffee. Van Bael et al. reported a similar magnitude of bird predation in agroforestry systems in comparison with adjacent forests, and reduced insect abundance and plant damage, particularly due to migratory birds . Nájera and Simonetti found that increasing complexity can enhance biodiversity in forest plantations, although different species have a diverse response to management . Colorado et al. found that highly structured coffee agroforests favors Neotropical migratory birds, including the provision of overwinter habitat. In Malaysia, oil palm forest supports less birds and has lower abundance of insectivores, omnivores and granivores but higher abundance of raptors and wetland birds in comparison with logged peat swamp forest . Although the bird communities supported by agroforestry remain high, the bird diversity is notably not the same as in the native forest. These agroecosystems were inhospitable for some of the forest specialist birds that rely primarily on food and resources present only in native ecosystems . Interestingly, it has been reported that bird richness could be higher in cacao agroforest plantations in comparison with native forest, although species that inhabited agroforest cacao were common generalist . However, bird diversity supported by agroforestry systems is higher than supported by agricultural monocultures .Although the adoption of agricultural techniques and practices dates back 10,000 years , agricultural landscapes were traditionally considered incompatible with conservation biology goals . More recently,raspberry grow in pots agricultural management and the adoption of different techniques and approaches have the potential to reduce negative impacts on bird populations and even enhance bird populations . The use of pesticides has been recognized as detrimental for non-target species since Rachel Carson published Silent Spring, documenting the impacts of DDT on bird breeding. After the banning of DDT in several countries, a new family of chemicals appeared with new impacts for wildlife. Neonicotinoid pesticides have heavily impacted bird populations via depleting insect populations, a bird food resource. It was shown that neonicotinoid pesticide could disrupt the thyroid gland in birds which affects the endocrine and reproduction systems . Neonicotinoids and other pesticides can persist in soil and soil water in the long term and their indirect effects are poorly understood . Reduced reproduction rate of secondary cavity nesters was reported in apple orchards sprayed with organochlorine pesticides . Granivores birds are also affected by the ingestion of pesticide treated seeds . It was reported that cumulative pesticides applications over multiple years decrease bird community specialization, favoring a few generalist species capable of persisting in simplified arable monoculture . In contrast, Henderson et al. , showed that use of poly cultures and reduced pesticide amounts increased grassland bird populations. In a risk assessment using birds as an indicator species to compare alternative farming systems with genetically modified herbicide tolerant crop production in the UK, wildlife friendly farm management provided better conservation outcomes via better provisioning of food resources and nesting habitats, in comparison with transgenic crops .
Misuse of pesticides have unintended consequences for non-target organisms and undermine environmental health for wildlife and humans. Organic agriculture is widely conceived of as a management approach that relies on optimization of natural cycles, avoids the use of synthetic fertilizers, pesticides and genetically modified crops, and minimizes external local impacts to the environment , although specific practices vary greatly between farms and certification schemes. Common practices include use of organic matter additions , crop rotations, greater reliance on biological nitrogen fixation by legumes, mechanical weed control, and the use of biological control for pest regulation. Organic management enhances biodiversity as reported by Rahmann in 82% of the 396 papers analyzed. Although the total surface area of certified organic agriculture corresponds to about 1% of the global agricultural land worldwide , organic agriculture has been reported as beneficial for wildlife in comparison to conventional agriculture . Tuck et al. in their meta-analysis documented a 34% increase in species richness of multiple taxa in comparison with conventional agriculture, a gain that remained stable for three decades. Plants benefited most, but positive effects on arthropods, birds and microbes were also reported . In a meta-analysis for Europe and North America Wilcox et al. found that for arable crops, bird abundance was higher in organic agricultural management than conventional management, although the response varied by species traits. Several studies on different taxa corroborate the positive effects of organic farming within the field and at its boundaries on plants , birds , insect pollinators , natural predators , soil microbial activity, beneficial arthropods, and earthworms . A smaller number of studies have reported a neutral influence of organic agriculture on biodiversity in comparison with intensive management, such as for birds within vineyards in Italy . Some authors contend that the benefit of organic farming varies with the taxa studied and the landscape context. For example, Gabriel et al. reported that landscape context interact significantly with organic management practices, such that conservation strategies should be considered from a ‘local perspective’. The effectiveness of organic practices to increase biodiversity likely depends not only on agricultural management, but also on structural diversity at different landscape scales . In terms of bird dietary groups, Genghini et al. found that in fruit orchards in Italy insectivorous birds were more abundant in organically managed fields than in conventionally managed fields. Similarly, Smith et al. reported that organic farms positively influenced insectivores birds only in monocultures surrounded by borders of semi-natural grassland. However, organic management had a positive effect on non-passerine birds richness independent of the vegetation context . Tillage is a common management practice worldwide to homogenize and standardize land cover surface, increase contact between the seed or crop root and soil, and for weed control and pest turnover.Tilled crop lands are not considered high quality habitat due to frequent soil disturbance and typically monoculture planting and high agrochemical application levels common in intensive agriculture . In terms of soil conservation, zero tillage or conservation tillage is a more environmentally friendly technique due to low impact on soil structure, reduced soil erosion, and increased soil carbon sequestration, with similar medium- and long-term yields in comparison to conventional tillage , however high levels of herbicide application on such systems remains a concern. Positive impacts of conservation tillage in comparison to conventional tillage has been reported for some farmland birds in the UK, particularly in late winter . Zero tillage can also increase seed and invertebrate availability which are key food sources for birds . In a comparison between no-till and conservation tillage in a soy monoculture, VanBeek et al. reported a higher abundance of birds with conservation value, higher nesting and higher nest success in notill in comparison with tilled farms. Shutler et al. reported higher abundance of birds in notill than in conventional farms in Canada, although all of the species were more prevalent in wetlands and wild sites than on farms. In Illinois a study compared the nesting success of birds under till and no-till soy crops and found a higher nesting density and nest success in no-till farms probably due to shelter and food resources provided by crop residues and weeds . However, it has been reported that no-till in corn–soy rotations can act as an ecological trap, due to birds’ perception of no-till cropland as suitable habitat and the subsequent negative impacts on nesting of farm equipment traffic and herbicide/pesticide applications common in such systems .