Article

Analysis of trends and agricultural drivers of farmland bird declines in North America: A review

Article

Analysis of trends and agricultural drivers of farmland bird declines in North America: A review

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Abstract

Globally, agriculture has intensified during the past 50 years due to increased mechanization, changes in the timing of farming operations, grassland conversion to cropland, and increased agrochemical inputs. Birds associated with farmlands and grasslands in North America have experienced severe declines over the last several decades, prompting the need for a comprehensive review of the drivers, mechanisms and magnitude of effects on bird populations. Here we evaluated changes in North American farmland bird populations over time and conducted a systematic review and analysis of the published literature to identify the major causes. Based on North American Breeding Bird Survey data, populations of 57 of 77 (74%) farmland-associated species decreased from 1966 to 2013. Multiple species exhibited highly congruent declines during the 1960s-1980s − a period with rapid changes in farming practices to low tillage systems, heavy pesticide use and widespread conversion of grassland habitat to cropland. The most severe declines occurred in aerial insectivorous birds (average change of −39.5% from 1966 to 2013), followed by grassland (‐20.8%) and shrubland (‐16.5%) bird species. Direct agricultural drivers impacting bird abundance, survival, and reproduction include loss of natural habitats, interference from farming equipment, and direct mortality or sublethal effects from pesticide exposure. Subtle interference with behaviour or physiology are reported through indirect drivers such as reduced food supplies, sublethal pesticide toxicity, habitat fragmentation and alteration, and disturbance. Indirect effects are likely significant for many species, particularly aerial insectivores, but detailed mechanistic studies are lacking. Our review of 122 studies found that pesticides (42% of all studies), followed by habitat loss or alterations (27%), were most predominant in negatively affecting farmland birds, with pesticides (93% negative) and mowing/harvesting (81% negative) having the most consistently negative effects. Modifications to farmland management such as reducing pesticide inputs through integrated pest management and maintaining or restoring uncultivated field margins and native habitat could positively influence farmland birds without significantly reducing agricultural crop yields.

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... In North America, habitat loss from the conversion of native grassland to row-crop agriculture and intensification from increased mechanization between the 1960s and 1980s is thought to underlie population declines for many species of grassland birds (Stanton et al., 2018). Of the North American avifauna, grassland birds show the largest population declines, with more than 700 million individuals lost across 31 species (from 1970 to 2017; Rosenberg et al., 2019). ...
... For objective 1, we developed an a priori hypothesis for biodiversity loss expected under the temporal process of habitat loss from the conversion of grassland to agricultural cultivation (Fahrig, 2003;Stanton et al., 2018). We predicted that if the biodiversity of grassland specialists declined with the historical process of habitat loss over time, then we would observe a decline in species richness along a gradual pattern of grassland availability (apparent habitat loss) over space. ...
... We used a continuum model to approximate responses of individual species to gradual changes in spatial patterns of grassland area and CRP restoration in the surrounding landscape (Fischer & Lindenmayer, 2006). By comparing model results to predictions, we made inductive inference to changes in grassland bird biodiversity from temporal process of habitat loss and restoration as benchmarks for evaluating CRP restoration of landscapes impacted by habitat loss from conversion to cropland (Herkert, 2009;Stanton et al., 2018). We estimated spatial variation using the hierarchical design of the IMBCR program with 5-ha point count plots nested within 1-km 2 grid cells, 9-km 2 grid cell buffers nested within BCRs, and BCRs nested within the study area (Pavlacky Jr. et al., 2017), and accounted for annual temporal variation using longitudinal data from 2010 through 2018. ...
Article
The decline of biodiversity from anthropogenic landscape modification is among the most pressing conservation problems worldwide. In North America, long‐term population declines have elevated the recovery of the grassland avifauna to among the highest conservation priorities. Because the vast majority of grasslands of the Great Plains are privately owned, the recovery of these ecosystems and bird populations within them depend on landscape‐scale conservation strategies that integrate social, economic, and biodiversity objectives. The Conservation Reserve Program (CRP) is a voluntary program for private agricultural producers administered by the United States Department of Agriculture that provides financial incentives to take cropland out of production and restore perennial grassland. We investigated spatial patterns of grassland availability and restoration to inform landscape‐scale conservation for a comprehensive community of grassland birds in the Great Plains. The research objectives were to 1) determine how apparent habitat loss has affected spatial patterns of grassland bird biodiversity, 2) evaluate the effectiveness of CRP for offsetting the biodiversity declines of grassland birds and 3) develop spatially explicit predictions to estimate the biodiversity benefit of adding CRP to landscapes impacted by habitat loss. We used the Integrated Monitoring in Bird Conservation Regions program to evaluate hypotheses for the effects of habitat loss and restoration on both the occupancy and species richness of grassland specialists within a continuum modelling framework. We found the odds of community occupancy declined by 37% for every 1 Standard Deviation (SD) decrease in grassland availability [loge(km2)] and increased by 20% for every 1 SD increase in CRP land cover [loge(km2)]. There was 17% turnover in species composition between intact grasslands and CRP landscapes, suggesting grasslands restored by CRP retained considerable, but incomplete representation of biodiversity in agricultural landscapes. Spatially explicit predictions indicated absolute conservation outcomes were greatest at high latitudes in regions with high biodiversity, whereas the relative outcomes were greater at low latitudes in highly modified landscapes. By evaluating community‐wide responses to landscape modification and CRP restoration at bioregional scales, our study fills key information gaps for developing collaborative strategies, and balancing conservation of avian biodiversity and social well‐being in agricultural production landscapes of the Great Plains.
... Most prominent are loss of native grassland, declining area of pasture and other semi-natural plant communities, increasing size of agricultural fields, row-Figure 2. Sample of bird species breeding in the Prairie Hardwood Transition (BCR 23) and predicted number of years (± 95% C.I.) until species will fall below a detection threshold for population assessment, resulting in potential imperilment status (Stanton et al. 2016). crop monocultures with denser and more uniform structure, increased inputs of fertilizers and pesticides, and reduced fallowing of fields (Herkert 1994, McLaughlin and Mineau 1995, Best et al. 1997, Murphy 2003, Stanton et al. 2018). The quality of forest bird habitat within portions of the region also declined, especially related to simplification (lost diversity) and fragmentation -caused by past timber harvest regimes, pathogens, invasive species, and over-abundant deer populations -largely impacting forest understory-nesting and areasensitive birds (Alverson et al. 1988, Robinson and Wilcove 1994, Donovan et al. 1995. ...
... Pesticide use may cause toxicity via ingestion of treated seeds, which can lead to mortality or sub-lethal effects (e.g. reduced nesting success) on birds that are frequently exposed (Hallmann et al. 2014, Stanton et al. 2018. Increased use of neonicotinoid insecticides in recent years has been linked to significant declines in grassland birds (Li et al. 2020); pesticide acute toxicity is a better correlate of U.S. grassland bird declines than agricultural intensification (Mineau and Whiteside 2013). ...
... Airborne Pollutants (OS 9.5).-Drift from herbicide use on croplands (e.g., toxic sprays) was considered a threat because it can lead to simplification of vegetation structure and plant diversity in nearby grasslands. Air-borne insecticides can reduce insect abundance, requiring birds to travel greater distances for food, and cause direct mortality or sub-lethal effects, resulting in reduced nest success, increased predation, and starvation risk (Martin et al. 2000, Stanton et al. 2018, Renfrew et al. 2019. ...
... Indeed, agricultural intensification is the second most prevalent threat to biodiversity, just after resource overexploitation (Maxwell et al., 2016), and its effects may even worsen within the coming decades (Kehoe et al., 2017). Since agricultural intensification is intimately linked with the use of pesticides, these chemicals have long been suspected to contribute to the loss of biodiversity observed worldwide, but direct evidence of their effects is surprisingly scant (see Wood & Goulson, 2017;Stanton et al., 2018 for recent reviews). ...
... Vol.: (0123456789) grasslands), declining biodiversity has been particularly well monitored and documented for avian species because many long-term ringing and monitoring schemes involving birds exist in many countries on different continents (e.g. France, Sweden, UK, US, Europe, North America; Comolet-Tirman et al., 2015;DEFRA, 2021;Li et al., 2020;Rosenberg et al., 2019;Stanton et al., 2018;Wretenberg et al., 2006). We chose to focus on farmland bird species (i.e. ...
... The impact of pesticides on farmland birds is primarily assessed using measurements of biodiversity loss (i.e. correlational studies) without investigating the processes leading to the observed patterns (Chiron et al., 2014;Geiger et al., 2010;Mineau & Whiteside, 2013;Mitra et al., 2011;Robinson & Sutherland, 2002;Stanton et al., 2018). Since the 1990s, this topic has received growing interest (Fig. 1). ...
Article
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For decades, we have observed a major biodiversity crisis impacting all taxa. Avian spe- cies have been particularly well monitored over the long term, documenting their declines. In particular, farmland birds are decreasing worldwide, but the contribution of pesticides to their decline remains controversial. Most studies addressing the effects of agrochemicals are limited to their assessment under controlled laboratory conditions, the determination of lethal dose 50 (LD50) values and testing in a few species, most belonging to Galliformes. They often ignore the high interspecies variability in sensitivity, delayed sublethal effects on the physiology, behaviour and life-history traits of individuals and their con- sequences at the population and community levels. Most importantly, they have entirely neglected to test for the multiple exposure pathways to which individu- als are subjected in the field (cocktail effects). The present review aims to provide a comprehensive over- view for ecologists, evolutionary ecologists and con- servationists. We aimed to compile the literature on the effects of pesticides on bird physiology, behaviour and life-history traits, collecting evidence from model and wild species and from field and lab experiments to highlight the gaps that remain to be filled. We show how subtle nonlethal exposure might be pernicious, with major consequences for bird populations and communities. We finally propose several prospec- tive guidelines for future studies that may be consid- ered to meet urgent needs.
... Currently, loss of biodiversity is a pervasive pattern across the globe (MacDougall et al., 2013), including losses of insects (Lister and Garcia 2018), which represents a serious threat to insectivorous birds. Many insectivorous birds are currently in decline (Nebel et al., 2010;Bowler et al., 2019), in part due to the intensification of farming activities such as crop production and livestock (Dennis 2003;Stanton et al., 2018). Most bird studies have focused on row crop production and have dealt less with impacts of cattle ranching, probably because the former has stronger negative impacts on birds and their environments (Stanton et al., 2018). ...
... Many insectivorous birds are currently in decline (Nebel et al., 2010;Bowler et al., 2019), in part due to the intensification of farming activities such as crop production and livestock (Dennis 2003;Stanton et al., 2018). Most bird studies have focused on row crop production and have dealt less with impacts of cattle ranching, probably because the former has stronger negative impacts on birds and their environments (Stanton et al., 2018). However, livestock have the potential to impact abundance, richness, diversity and abundance of insects (Dennis 2003;Stanton et al., 2018), although the magnitude of such effects is poorly known. ...
... Most bird studies have focused on row crop production and have dealt less with impacts of cattle ranching, probably because the former has stronger negative impacts on birds and their environments (Stanton et al., 2018). However, livestock have the potential to impact abundance, richness, diversity and abundance of insects (Dennis 2003;Stanton et al., 2018), although the magnitude of such effects is poorly known. ...
Article
Food selection is a key aspect of a bird's life history strategy, so understanding how birds respond to variation in food abundance is relevant to evaluating their general ecology and survival, and also the potential consequences of the degradation of environments impacted by livestock. We studied the dietary ecology of Vermilion Fly-catchers (VEFL) and Fork-tailed Flycatchers (FTFL), two insectivores and Neotropical austral migrants, during their breeding season. We worked in areas with and without cattle ranching in the Espinal biome of La Pampa, Argentina. We found different arthropod prey abundance for both flycatchers according to arthropod orders and/ or study sites, suggesting that livestock may impact food abundance. Both consumed similar prey and positively selected for hymenopterans and coleopterans, and FTFL also positively selected for orthopterans. VEFL selected nest sites with a lower abundance of heteropterans and FTFL selected sites with a higher abundance of co-leopterans. Additionally, VEFL nest survival was negatively related to the abundance of hemipterans and FTFL nest survival was positively related to the abundance of coleopterans. This study helps fill gaps on the general ecology of species that breed in rangelands, and highlights the importance of similar studies to formulate effective conservation planning for the Espinal biome.
... Farmland birds are declining globally (Green et al., 2005;Reif and Vermouzek, 2019; Stanton et al., 2018) mainly due to increasing anthropogenic pressure and activities such as intensive agriculture, hunting, pesticide and other agrochemical use, and increasing urbanization (Stanton et al., 2018). Consequently, many birds that use agricultural landscapes are threatened (IUCN, 2020a;Sundar and Subramanya, 2010) and declining faster than for other habitats (PECBMS, 2020), highlighting the need to understand the factors that influence bird community composition in agricultural landscapes. ...
... Farmland birds are declining globally (Green et al., 2005;Reif and Vermouzek, 2019; Stanton et al., 2018) mainly due to increasing anthropogenic pressure and activities such as intensive agriculture, hunting, pesticide and other agrochemical use, and increasing urbanization (Stanton et al., 2018). Consequently, many birds that use agricultural landscapes are threatened (IUCN, 2020a;Sundar and Subramanya, 2010) and declining faster than for other habitats (PECBMS, 2020), highlighting the need to understand the factors that influence bird community composition in agricultural landscapes. ...
... Consequently, many birds that use agricultural landscapes are threatened (IUCN, 2020a;Sundar and Subramanya, 2010) and declining faster than for other habitats (PECBMS, 2020), highlighting the need to understand the factors that influence bird community composition in agricultural landscapes. Various factors influence richness, and abundance of bird communities within agricultural landscapes, including field size, management practices, landscape heterogeneity (composition and configuration), crop types, farmstead presence, and pesticide inputs (Fahrig et al., 2015;Lee and Goodale, 2018;Muñoz-Sáez et al., 2017;Shew and Nielsen, 2021;Stanton et al., 2018;Tryjanowski et al., 2011;Wilson et al., 2017). Seasons also change the community structure of the birds, including resident, breeding, or migrating species, in agricultural landscapes (Goijman et al., 2015;Herzon et al., 2014;Muñoz-Sáez et al., 2017;Ş ekercioglu et al., 2019), but their impact on bird diversity in agricultural landscapes are understudied relative to other factors. ...
Article
Farmland birds are declining globally due to anthropogenic activities, with particularly few studies in Asian agricultural landscapes. Various studies have examined the impacts of landscape heterogeneity on farmland bird composition, but few have considered seasonal changes in bird diversity and examined functional feeding guild assemblages. Here, we disentangle the impact of seasonal variation (summer, monsoon, and winter), cropping practice (mixed crop, monocultural-crop, and fallow land), crop type (rice, wheat, maize, sugarcane, and other crops), landscape heterogeneity, and the number of houses and trees on the richness and abundance of farmland birds and their feeding guilds conducted within human-dominated agricultural landscapes of lowland Nepal. We established 116 transects (farmland = 100, forest = 8, and river = 8), and each transect was visited nine times from April 2018 to December 2019, with forests and river transect to test the dissimilarities in bird composition between those habitats and farmlands. We recorded 201 bird species in farmland, 133 in the forest, and 131 in river habitats. Bird composition on farmlands showed more dissimilarity with forest than river transects. We recorded nine globally, and 26 nationally threatened birds in farmlands. Seasonal variation and cropping practice significantly influenced the richness of all farmland birds and resident birds only, whereas species abundances vary by season only. We recorded higher species richness in the winter season and mixed crop fields but greater abundance in the monsoon and monoculture crop fields. Farmland bird richness increased with increasing tree numbers but decreased with increasing house numbers. Sugarcane fields had the highest bird richness within crop species, whereas rice fields had the greatest abundance. Seasons and cropping practice also shaped the assemblages of feeding guilds differently. In the context of increasing crop intensification globally, our study suggests that the governments in this region should encourage farmers to cultivate mixed crops and simultaneously restrict the urbanization of farmlands to protect bird diversity. Seasonality should be factored into analyses aimed at understanding bird diversity in agricultural landscapes.
... Over the past several decades, farmland management and mechanization have dramatically intensified worldwide. This intensification has been linked to declines in many elements of farmland biodiversity including arable plants, invertebrates and birds (Newton, 2004;Powney et al., 2019;Richner et al., 2017;Stanton et al., 2018). ...
... The causal factors of these declines relate to key changes that took place over this period including an increase in farm size and a decline in the number of individual farms in the United States (Stanton et al., 2018). Other changes in Europe and the United States include shifts in the timing of farming activities (e.g. a move from spring to winter cropping and the consequent loss of over winter stubbles), the use of non-traditional crops (e.g. ...
Article
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1. Across Europe, farmland bird populations have continued to decline since the 1970s owing to the intensification of farming practices. Studies of such declines have tended to focus specifically on either the impacts of habitats (nesting and foraging), nest predators or prey availability on bird demographics. The study presented here provides new insights into the relative effects of each of these factors on yellowhammer nest survival. The yellowhammer was selected for this study as it is a UK Red‐Listed bird species whose population is in decline across much of Europe. 2. We use a long‐term dataset of 147 nests, monitored between 1995 and 2007, to provide an insight into how yellowhammer nest survival is influenced by nesting habitat (nest concealment and nest height), foraging habitats (habitat coverage within 100 m of nests), the removal of nest predators (magpie Pica abundance as an inverse measure of avian predator removal through gamekeeping) and food availability (measured with a D‐vac invertebrate suction sampler). 3. Our results indicated that yellowhammer hatching success was negatively related to the coverage of spring agri‐environment scheme habitats, a group which represents invertebrate‐rich agri‐environment habitats, but hatching success increased with nest height. Fledging success was positively related to the coverage of the seed‐rich habitat wild bird seed mixture. The farm‐level abundance of yellowhammer chick‐food invertebrates declined over the study period. 4. Our results highlight the importance of simultaneously considering multiple agents that shape avian breeding success, that is their ability to produce offspring, to inform conservation management. Our key finding for land managers relates to the positive relationship between the proportion of seed rich foraging habitat within the yellowhammer's average foraging range and yellowhammer fledging success, which shows that a habitat intended primarily to provide winter food resources is also important to breeding birds. Chick food abundance in this habitat was, however, similar to broadleaf and cereal crops. We recommend that this habitat should be provided near to potential yellowhammer nesting sites and adjacent to invertebrate‐rich agri‐environment scheme habitats such as beetle banks and conservation headlands to further boost invertebrate resources for a declining farmland bird. Our results highlight the importance of simultaneously considering multiple agents that shape avian breeding success, that is. their ability to produce offspring, to inform conservation management. For land managers, our key finding relates to the positive relationship between the proportion seed rich foraging habitat within the yellowhammers average foraging range and yellowhammer fledging success, which shows that a habitat intended primarily to provide winter food resources is also important to breeding birds. Chick food abundance in this habitat was similar to crops. We therefore recommend that this habitat be provided near potential yellowhammer nesting sites and invertebrate‐rich agri‐environment scheme habitats such as beetle banks and conservation headlands are positioned adjacent to further boost invertebrate resources for a declining farmland bird.
... Trends of declining diversity and biomass of insects [1, 2], earthworms [3] and birds [4] are observed in agroecosystems and non-crop ecosystems around the world [5][6][7]. ...
... In general, insecticides are considered more toxic to honeybees, earthworms and birds than herbicides [4,127,128]. For example, the neonicotinoid insecticide imidacloprid is about 846 times more toxic to honeybees than the most orally toxic herbicide in the present study, aminopyralid [91]. ...
Article
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Background Pesticide use has been associated with risks for human health and an overall decline in biodiversity. Although herbicides are the most commonly used pesticides worldwide, they have received less attention in this debate. We investigated the extent to which long-term trends in herbicide use in Austria influence potential toxic exposures to non-target organisms and potential risks to humans. We analyzed official sales data of 101 herbicide active ingredients (AIs) approved in Austria between 2010 and 2019 regarding their ecotoxicological properties based on lethal doses (LD 50 and LC 50 ) weighed by their persistence in the environment (DT 50 ) for honeybees ( Apis mellifera ), earthworms ( Eisenia fetida ), and birds ( Serinus serinus ). Human health risks were qualitatively assessed based on official hazard statements for the AIs used. Results In Austria, herbicide amounts sold decreased significantly by 24% from 1480 to 1123 tonnes between 2010 and 2019. This also led to a considerable decrease in the amounts of AIs classified by H-statements of the EU Pesticides Database: − 71% acute inhalation toxicity, − 58% reproductive toxicity,− 47% specific target organ toxicity. Yet, 36% of herbicides used were still classified as highly hazardous pesticides according to the Pesticide Action Network. Surprisingly, over the same period, toxic loads to honeybees increased by 487% (oral exposure), while lethal toxic loads to earthworms increased by 498%, and to birds by 580%. This can be attributed to a shift toward the use of more acutely toxic and especially more persistent AIs. The most problematic AI for honeybees, earthworms, birds and humans was the highly persistent diquat. The further ranking of the most toxic herbicides varied considerably depending on the organism. It is important to note that this toxic load assessment, like official environmental risk assessments, evaluates the potential risk but not the actual fatalities or real-world exposure. Conclusions Our results show a trade-off between herbicide amounts and toxicological hazards to humans and other non-target organisms. These interdependencies need to be considered when implementing pesticide reduction targets to protect public health and biodiversity, such as the EU´s “farm-to-fork” strategy, which aims to reduce the amounts and risks of synthetic pesticides.
... For example, continent-wide monitoring programs such as the North American Breeding Bird Survey (reviewed in ref. 14) or the Pan-European Common Bird Monitoring Scheme (https://pecbms.info/trends-and-indicators/speciestrends/) have revealed aggregate losses of billions of birds in recent decades (15)(16)(17)(18)(19). These declines span biomes and include both common and rare species of diverse ecologies and life histories (15,17,(20)(21)(22), stimulating widespread concern over the conservation prospects of birds worldwide. ...
... Conclusions. Our findings of systematic avian population declines in intact tropical forests bolster the available evidence demonstrating declines in bird abundance across diverse biomes and disparate taxa worldwide (15)(16)(17)(18)(19). The widespread declines of tropical birds in a large, protected area are a particular cause for concern. ...
Article
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Significance We leveraged a 44-y population study of Neotropical understory birds from a protected forest reserve in central Panama to document widespread and severe declines in bird abundance. Our findings provide evidence that tropical bird populations may be undergoing systematic declines, even in relatively intact forests. The implications of these findings are that biodiversity baselines may be shifting over time, and large tracts of tropical forest may not be sufficient for maintaining stable bird populations. Our study highlights the importance of long-term monitoring for detecting cryptic losses in biodiversity and motivates the need for future work drilling down to the underlying mechanisms to understand and mitigate future declines.
... To increase food productivity for humans, farmland landscapes have experienced major changes over recent decades that have affected ecosystem functions and biodiversity (Stanton et al., 2018). Agricultural intensification involving massive use of pesticides (DiBartolomeis et al., 2019;Malaj et al., 2020) has altered population dynamics of farmland birds (Mineau and Whiteside, 2013;Hallmann et al., 2014;Gibbons et al., 2015;Stanton et al., 2018). ...
... To increase food productivity for humans, farmland landscapes have experienced major changes over recent decades that have affected ecosystem functions and biodiversity (Stanton et al., 2018). Agricultural intensification involving massive use of pesticides (DiBartolomeis et al., 2019;Malaj et al., 2020) has altered population dynamics of farmland birds (Mineau and Whiteside, 2013;Hallmann et al., 2014;Gibbons et al., 2015;Stanton et al., 2018). Numerous toxicological studies on farmland birds showed that exposure to pesticides can impact reproduction by altering endocrine, neurological and immunological systems, and thereby adversely affect the health and behaviour of breeding birds and offspring (Mitra et al., 2011;Pandey et al., 2017). ...
Article
Numerous toxicological studies have shown that ingestion of pesticides can induce physiological stress in breeding birds, with adverse consequences on egg laying parameters and offspring quality through parental effects. However, previous studies do not mimic current levels of pesticide residues in typical landscapes, and they do not consider potential cocktail effects of pesticides as they occur in the wild. Herein, we explored whether realistic pesticide exposure affected reproduction parameters and offspring condition through parental effects in Grey partridge. We fed 24 breeding pairs with either seeds from conventional agriculture crops treated with various pesticides during cropping, or organic grains without pesticide residues as controls. The conventional and organic grain diets mimicked food options potentially encountered by wild birds in the field. The results showed that ingesting low pesticide doses over a long period had consequences on reproduction and offspring quality without altering mortality in parents or chicks. Compared with organic pairs, conventional pairs yielded smaller chicks at hatching that had a lower body mass index at 24 days old. Additionally, these chicks displayed lower haematocrit when body mass index was higher. Therefore, ingestion of conventional grains by parents resulted in chronic exposure to pesticide residues, even at low doses, and this had detrimental consequences on offspring. These results demonstrate a sublethal effect of pesticide residues through parental effects. The consequences of parental exposure on chicks might partly explain the decline in wild Grey partridge populations, which raises questions for avian conservation and demography if current agrosystem approaches are continued.
... In Indiana alone, only 1.1% of the agricultural landscape is currently used for woodlands or conservation (USDA, 2019). In addition, 74% of farmland-associated species decreased from 1966 to 2013, caused by rapid changes in farming practices, including widespread conversion of grassland habitat to cropland, habitat fragmentation, mowing, harvesting, and heavy pesticide use (Stanton et al., 2018). This habitat loss equally threatens pollinator populations (USDA, 2017). ...
... Buffers are seen as one of the last strongholds for many species in intensive farmland (Staley et al., 2019;Walker et al., 2006) and effectively conserve biodiversity (Tooker et al., 2020). Maintaining and restoring buffers on field margins supports farmland birds and pollinators without significantly reducing agricultural crop yields (Stanton et al., 2018). The vegetation and high soil organic matter in buffer zones aid carbon sequestration, helping mitigate carbon loss associated with intensive tillage (Haris et al., 2013;Paustian et al., 1997). ...
Article
Climate BufferNet is an educational, visual simulation designed to engage higher education students in the Midwestern United States with ideas for improving rural landscape planning outcomes. Past and present social and economic forces shaping the midwestern agricultural landscape have fundamentally transformed its natural systems, impacting food security, biodiversity, and community and ecosystem resilience to climate change. However, the lack of specific knowledge concerning these socioecological and economic forces and their feedback loops constitutes an information barrier to stakeholders new to the decision-making frameworks that shape this complex socioagricultural landscape. This article presents a serious socioecological gaming simulation case study as a framework for familiarizing landscape architecture students with the complex interactive characteristics of these systems. The Climate BufferNet study immersed students in an interactive, co-learning visual media environment that confronted them with real-world challenges of balancing economic priorities with the degraded ecological feedback loops now prevalent in this multifunctional landscape. The results of student evaluations from initial playtesting, presented here, revealed that the simulation accurately demonstrates the difficulty in balancing environmental and economic goals. Further, qualitative coding of student responses shows that players were using the simulation to actively experiment with spatial configurations of conservation practices and decipher rules for targeting their actions. The results of these initial pilot tests, documented here, demonstrate both the potential for engaging landscape architects in rural landscape planning and the need for greater attention to the complexities of environmental and economic tensions between biodiversity, climate change, and ecosystem services.
... In Europe, agricultural intensification in recent decades has led to a widespread decline in biodiversity (Chamberlain et al., 2000;Heldbjerg et al., 2018;Stanton et al., 2018). However, the consequences of these intensive practises widely vary between regions, with some agricultural areas still sustaining a relatively rich biodiversity while others have lost a vast majority of their components (Karp et al., 2012;Kremen and Miles, 2012). ...
... Changes in agricultural practices across Europe over the last four decades have mainly resulted in habitat homogenization or fragmentation, degradation to outright destruction, many of these effects being involved in farmland bird declines (Donald et al., 2006;Stanton et al., 2018). However, it is difficult to identify the specific features of the landscape that influence populations, as empirical data are often limited in time and space. ...
Article
Agricultural changes in recent decades have led to a widespread loss of biodiversity, with habitat loss considered as the main factor in the decline. The European turtle dove is one of the farmland birds that has declined markedly in Europe, leading the IUCN to downgrade its status in 2015 from “Near Threatened” to “Vulnerable”. Knowledge of how habitat factors and agricultural practices influence the turtle dove population is crucial for the conservation of this species through the implementation of targeted measures. Here we investigate how foraging and nesting habitats influence the abundance of turtle doves at national and regional scales, using a 23-year dataset from point counts carried out throughout France, a stronghold country for this species during the breeding season. We found that turtle dove abondance was positively affected by fallow lands, both at national and regional scales. Turtle dove abundance was also negatively affected by fodder crop area at national scale, but the effect was detected in only four of the 13 French regions. We also showed that an increase in hedgerows length had a positive effect on turtle dove abundance. On the other hand, forest edges length showed a bell-shaped trend, suggesting that an increase in forest edges length may have a favourable effect on turtle dove abundance only up to a given threshold. We suggest that targeted conservation measures combining an increase in fallow lands and hedgerows length could allow the stabilisation or even an increase in turtle dove abundance in France, but also in European countries with similar landscapes.
... Since the 1960s, the intensification of agricultural practices has been identified as a major cause of decline for birds, especially farmland species (Donald et al., 2001;Stanton et al., 2018). In addition to habitat loss and fragmentation, the massive use of pesticides has also been suggested to be involved in these population declines (e.g., reviewed by Stanton et al., 2018). ...
... Since the 1960s, the intensification of agricultural practices has been identified as a major cause of decline for birds, especially farmland species (Donald et al., 2001;Stanton et al., 2018). In addition to habitat loss and fragmentation, the massive use of pesticides has also been suggested to be involved in these population declines (e.g., reviewed by Stanton et al., 2018). Indeed, about 2 million tonnes of pesticides are used each year worldwide to protect crops from potential diseases and pests (Ali et al., 2021) and they are commonly detected in wildlife, including birds (De Souza et al., 2020;Montaigu and Goulson, 2020). ...
Article
Triazole compounds are among the most widely used fungicides in agroecosystems to protect crops from potential fungal diseases. Many farmland birds spend a significant part of their life cycle in agroecosystems, which may chronically expose them to pesticides. We experimentally tested whether exposure to environmental concentrations of tebuconazole could induce a contamination of the eggs by tebuconazole in an agroecosystem sentinel species, the house sparrow (Passer domesticus). Wild-caught adult sparrows were maintained in captivity and exposed (exposed group) or not (control group) for seven months to tebuconazole through drinking water. Eggs were opportunistically collected for the determination of tebuconazole concentration by Liquid Chromatography coupled to tandem Mass Spectrometry in eggs. We found that eggs from exposed parents all contained tebuconazole with a mean concentration of 1.52 ng g−1 dry weight. In eggs from control parents, the tebuconazole concentration was below the limit of quantification (0.23 ng g−1 dry weight) for 11 out of 13 eggs. Thus, our study demonstrates for the first time that environmental exposure of female birds to tebuconazole can translate into egg contamination by this fungicide.
... Furthermore, animals attempting to cross roads are often killed by vehicles. Vehicle collisions cause millions of animal deaths on European roads each year (Grilo et al. 2020), including a wide range of taxonomic groups Apart from increasing fragmentation via roads, changes in the landscape are predominantly driven by agricultural intensi cation and expansion, leading to deterioration of habitat suitability for many species (Raven and Wagner 2021;Stanton et al. 2018). For example, homogenization though altered agricultural land use in Europe has led to a general decline in farmland biodiversity (Benton et al. 2003; Carmona et al. 2020). ...
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ContextRoads are ubiquitous in human inhabited landscapes, and can impact animal movement and population dynamics, due to barrier effects, road mortality, but also by providing resources at road verges. Thus, we need a better understanding of how roads, in interaction with seasonal changes in habitat structure, affect space use and habitat selection of the animals that persist in these landscapes.Objectives Here, we used the European hare ( Lepus europaeus ) as model species to investigate how human-induced changes in landscape composition – measured as road density, land cover type, and field size – affect home range location, seasonal habitat selection and road crossings, which are likely to correlate with wildlife-vehicle collision risk.Methods We collected >240,000 GPS positions of 90 hares from three populations (one in Denmark and two in Germany) that differed regarding agricultural intensification and road density. Using this data, we analyzed home range location and habitat selection (using step-selection functions) in relation to roads, habitat composition, and seasonality, and quantified how these factors affected road crossings by hares.ResultsIn comparatively more heterogeneous landscapes, hares established home ranges in areas with lower road densities compared to the surrounding area, but not in more simple landscapes. Moreover, hares generally avoided main roads and selected for minor roads during the vegetation growth seasons, especially in areas with comparatively less heterogeneous habitat structure. After accounting for main road density, the number of main road crossings was comparatively higher in simpler landscapes, and the number of daily main road crossing changed seasonally.Conclusions Our findings emphasize that it is important to distinguish between road types, as different roads can have different impacts on animals (e.g. small roads providing foraging opportunities via roadside vegetation and large roads being avoided). Moreover, animals in comparatively more heterogeneous landscapes are better able to adjust their habitat selection to avoid main roads than animals inhabiting simpler landscapes. More generally, homogenous landscapes increase the space use requirements of animals, leading to increased probability of road crossings, which in turn might affect population dynamics via increased road mortality risk.
... Conventional farming practices have caused an important decline in the nesting sites of cavity-nesting birds (Cockle et al., 2011). Furthermore, agricultural landscapes can be a major barrier to the movement of wild insectivorous birds (Ş ekercioglu et al., 2002;Assandri et al., 2017a;Jerrentrup et al., 2017;Muñoz-Sáez et al., 2017;Stanton et al., 2018). In Chile, most secondary cavity-nesting birds are insectivorous (Ibarra et al., 2017). ...
Article
Insectivorous birds provide key ecosystem services for agricultural production, such as biological pest control. However, habitat loss and degradation by agriculture are among the main causes of biodiversity loss globally, including the recent decline in bird populations. Habitat loss has particularly affected insectivorous birds due to the associated decrease in the availability of suitable nesting sites. Our study assessed a tool of ecological intensification to increase insectivorous bird abundance and biological control in vineyards. We evaluated the effects of nest boxes on prey removal by insectivorous birds in five vineyards in central Chile, using a two-year sentinel prey experimental trial. Our results showed significantly more sentinel larvae removal by birds in plots with nest boxes than control plots. Deploying the nest boxes resulted in a 43% higher consumption of sentinel prey. Therefore, we recommend using nest boxes as an environmentally-friendly method to increase native predators and enhance biological control in agricultural fields. This would have the potential to improve biodiversity conservation and maximize crop yields.
... Although we did not observe reduced nestling mass or provisioning rates, reduced arthropod biomass could potentially have larger impacts in resource-poor habitats or when herbicide is applied over especially large areas. Given that arthropod declines in response to herbicide and pesticide use are a growing concern for breeding birds (Britschgi et al. 2006;Stanton et al. 2018), further work is needed to ensure that restoration using herbicide does not negatively impact arthropod populations in the long term. ...
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Tall fescue (Schedonorus arundinaceus) is a widespread invasive grass in the U.S. that degrades habitat quality for biodiversity. Herbicide followed by seeding of native plants reduces tall fescue and is predicted to restore habitat quality over time, but little is known about short‐term (1‐2 year) impacts on native species. We conducted a landscape‐scale controlled experiment to assess the short‐term effects of herbicide and seeding on the reproduction of an obligate grassland bird, the dickcissel (Spiza americana). In 2014, four sites in southern Iowa were each subdivided into three patches (mean 7 ha). One patch in each site was treated with glyphosate herbicide (spray‐only), one with herbicide and native seeding (spray‐and‐seed), with the third serving as a control. Two sites were grazed by cattle from April‐July and two sites were ungrazed. We monitored dickcissel reproduction in 2016, finding that they were more abundant, built more nests, experienced less cowbird parasitism, had increased nest survival, and produced more fledglings on spray‐only and spray‐and‐seed treatments compared to control patches. Dickcissels nested infrequently on grazed sites—especially grazed control patches. We did not detect any impacts on clutch size, provisioning rates, or nestling mass, but Araneae (spiders) and Lepidoptera larvae (caterpillars) may have been smaller on sprayed patches. Positive responses by dickcissels were likely due to successful reduction of tall fescue and improved access to suitable nest sites through increased vegetation heterogeneity. Our results indicate that using herbicide and seeding to restore tall fescue‐dominated sites improves habitat quality for this grassland bird, shortly after restoration. This article is protected by copyright. All rights reserved.
... This increased bird diversity and the changes in community composition may be due to improved water quality (unfortunately, preremediation data on water quality are limited, so we cannot provide a thorough test) as well as the improved physical characteristics of the TSE ponds compared to the lagoons prior to remediation (see Section 4.2). Supporting this interpretation, the abundance of individuals and the diversity of bird species are known to be negatively impacted by pollutants in other contexts (e.g., heavy metal pollution from smelting [38]; electronic waste from recycling centers [39]; agricultural chemicals [40]; urban air pollution [41]). Unfortunately, the preand post-remediation surveys were conducted by different observers, which may add error to the pre-and post-remediation comparison. ...
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Qatar, a peninsular country in the Persian Gulf, is significant to avian species due to its location along the African–Eurasian Flyway, a key migratory path. Receiving untreated domestic and industrial liquid waste from Qatar in the past, Al Karaana Lagoons have since been reconstructed as an artificial wetland to address the growing environmental concern posed by contamination build-up. This study documents the changes in biodiversity at Al Karaana Lagoons following their environmental remediation. Data collected (2015 and 2017) by Ashghal (Public Works Authority) prior to project implementation was analyzed alongside data collected independently following project completion (2019–2021). There was a marked increase in bird biodiversity following remediation, including substantial use by migratory species and resident breeders. Further analysis of water quality data of the TSE (treated sewage effluent) ponds shows that they are eutrophic but still support substantial bird life. The project’s success demonstrates how reclaimed lands can provide important habitats to local and migratory birds and encourages similar restoration efforts in the future in both Qatar and elsewhere. We call for the continued monitoring of the site and the implementation of guidelines for the use of the site that balance human activities and habitat quality.
... One of the most prominent examples is the massive decline of the raptor population globally due to eggshell thinning after bioaccumulation caused by exposure to dichloro-diphenyltrichloroethane (DDT) (Newton and Bogan 1974). While acute intoxication from pollutants generally appears as a less poignant and immediate threat, severe indirect effects of pollutants, primarily agrochemicals, on farmland birds are well-described drivers of population declines (Stanton et al. 2018). Other threats at the population level associated with chemical exposure have been reported for various avian taxa, such as global lead poisonings of raptor and waterbird species (Sonne et al. 2019). ...
Article
A literature review of bioaccumulation and biotransformation of organic chemicals in birds was undertaken, aiming to support scoping and prioritization of future research. The objectives were to characterize available bioaccumulation/biotransformation data, identify knowledge gaps, determine how extant data can be used, and explore the strategy and steps forward. An intermediate approach balanced between expediency and rigor was taken given the vastness of the literature. Following a critical review of > 500 peer-reviewed studies, > 25,000 data entries and 2 million information bytes were compiled on > 700 organic compounds for ~ 320 wild species and 60 domestic breeds of birds. These data were organized into themed databases on bioaccumulation and biotransformation , field survey , microsomal enzyme activity , metabolic pathway , and bird taxonomy and diet . Significant data gaps were identified in all databases at multiple levels. Biotransformation characterization was largely fragmented over metabolite/pathway identification and characterization of enzyme activity or biotransformation kinetics. Limited biotransformation kinetic data constrained development of an avian biotransformation model. A substantial shortage of in vivo biotransformation kinetics has been observed as most reported rate constants were derived in vitro. No metric comprehensively captured all key contaminant classes or chemical groups to support broad-scope modeling of bioaccumulation or biotransformation. However, metrics such as biota-feed accumulation factor, maximum transfer factor, and total elimination rate constant were more readily usable for modeling or benchmarking than other reviewed parameters. Analysis demonstrated the lack of bioaccumulation/biotransformation characterization of shorebirds, seabirds, and raptors. In the study of bioaccumulation and biotransformation of organic chemicals in birds, this review revealed the need for greater chemical and avian species diversity, chemical measurements in environmental media, basic biometrics and exposure conditions, multiple tissues/matrices sampling, and further exploration on biotransformation. Limitations of classical bioaccumulation metrics and current research strategies used in bird studies were also discussed. Forward-looking research strategies were proposed: adopting a chemical roadmap for future investigations, integrating existing biomonitoring data, gap-filling with non-testing approaches, improving data reporting practices, expanding field sampling scopes, bridging existing models and theories, exploring biotransformation via avian genomics, and establishing an online data repository.
... The specific causes of declining grassland bird populations are complex but failure of young birds to survive and reproduce is clearly a major concern (North American Bird Conservation Initiative Canada, 2019; Renfrew et al. 2019;Wilsey et al., 2019;Stanton, Morrissey, & Clark, 2018;Ethier et al., 2017;Ethier & Nudds, 2015;Hill et al., 2014;. Young birds depend on their parents for food for a long period and are especially vulnerable until they fledge. ...
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Perennial forage production exists in Ontario to support the livestock industry, but also provides nesting habitat for grassland birds such as the threatened Bobolink (Dolichonyx oryzivorus) and Eastern Meadowlark (Sturnella magna). Delaying hay harvest until July 15 or later allows most nestling birds to leave the nest, but the nutritional value of hay decreases substantially. This project estimated the nutritional and economic impact of delaying the first hay cut until after July 15 on beef and dairy production in Ontario, Canada. Forage crops were sampled across Ontario, analysis of nutritional value performed, and effects on production and economics modelled. 634 samples were collected over 13 weeks at 16 sites from May 21 to August 14 during 2014 and 2015. As expected, nutritional quality declined over the season. Crude protein decreased by 5.2%, total digestible nutrients by 7.7%, neutral detergent fibre digestibility (NDFd48) by 20.1%, while lignin increased by 3.5%, neutral detergent fibre by 13.1%, and acid detergent fibre by 9.9%. Estimated yearly milk production decreased 10.9 kg or C$7.87/dairy cow for each day of delay in harvest (2017 values). Estimated growth of backgrounding beef steers decreased 1.56 kg or C$5.49/head for each day of delay in harvest. This translated into lost revenue per acre for backgrounding steers of C$31 per acre and C$45 per acre for over wintering beef cows for a delay from mid-June to mid-July. Some agri-environmental incentives in Canada, US and Europe offset the reduced revenue due to lower quality forages. This analysis informs farmers about the cost of practices to benefit grassland birds and provides empirical data on how to structure stewardship incentives for these practices.
... When controlled for the effects of agricultural intensification and landuse change, declines of grassland birds in particular have been linked to the widespread use of pesticides. A review of agricultural drivers of farmland-associated bird species in North America found that 42% of studies found a negative impact of pesticides, while 27% of studies found a negative impact of habitat loss (Stanton et al. 2018). Neonicotinoid pesticide use in the USA was associated with a 4% annual decline of grassland birds and a 3% annual decline of insectivorous birds (Li et al. 2020). ...
Article
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There is increasing awareness of the negative ecological and environmental effects of widespread use of pesticides on the landscape. Spillover or drift of pesticides from agricultural areas has been shown to impact species health, reproduction, and trophic dynamics through both direct and indirect mechanisms. Neonicotinoid insecticides are associated with observed declines of insectivorous and grassland birds, and these environmental pollutants are a significant conservation concern for many species that have experienced past or current population declines. Due to the high efficacy of these modern insecticides in depressing local insect populations, insectivorous birds can be negatively impacted by a pesticide-mediated reduction in food supply. Neonicotinoids may act synergistically with other stressors, such as habitat loss, to exacerbate threats to species or population viability. The Tricolored Blackbird is an insectivorous grassland bird of conservation concern in California, USA. Due to the high association of this species with agricultural habitats, we sought to quantify the amount of neonicotinoid residues in Tricolored Blackbird carcasses as a first step in assessing how this species may be impacted by pesticides. Out of 85 salvaged carcasses sampled ( N = 24 adults, N = 3 fledglings, and N = 58 nestlings), only two contained detectable levels of target compounds. These were an adult and one nestling that contained clothianidin residue (40 ppb and 7 ppb, respectively); both of these birds were salvaged from breeding colonies associated with dairy farms in Kern County, California. We suggest that further work is needed to assess neonicotinoid exposure of Tricolored Blackbirds in dairy-associated breeding colonies.
... On peut donc anticiper que mettre en oeuvre une gestion appropriée au sein de ces emprises pour développer leurs fonctions d'habitat, de conduit et éventuellement de source dans le but de recoloniser des paysages avoisinants dégradés [6], puisse produire des effets à l'échelle locale immédiate mais aussi à grande échelle. Ceci contribuerait directement à la lutte contre le déclin général d'espèces de la biodiversité dite ordinaire, parmi lesquelles des adventices et des insectes volants [13,14], mais aussi en aval, d'espèces bénéficiaires parmi les oiseaux [15]. En France, agir de la sorte pourrait s'inscrire notamment dans le cadre de plans nationaux d'actions (PNA) tels que pour la préservation des plantes messicoles et des insectes [16,17,18]. ...
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Depuis quelques années, certaines parties d'emprises des divers types d'infrastructures linéaires de transport (ILT) sont reconnues comme de potentiels abris écologiques pour la flore et l'entomofaune locales. Pour développer une politique éclairée de mise à profit de cette opportunité pour la conservation des espèces et le rétablissement de connectivités écologiques au sein des paysages, il est essentiel de connaître le patrimoine de refuge écologique potentiel (REP) offert par ces emprises à l'échelle nationale. Prenant en compte les principales contraintes d'exploitation des ILT, leurs caractéristiques géométriques et leur environnement, un calcul a été conduit sous système d'information géographique (SIG) pour estimer le développement linéaire et la surfacique de REP en France métropolitaine. Le réseau de REP s'étend sur 88 094 km (39 % associés au réseau de transport d'électricité, 34 % au réseau ferroviaire, 18 % au réseau routier, 9 % au réseau navigable). Sa surface minimale totale est estimée à 2 025 km 2 . L'État est dépositaire d'une part très importante du linéaire de REP (46,2 %), en particulier à travers son domaine public ferroviaire (32,0 % du total). La part des collectivités territoriales et sociétés concessionnaires (53,8 %) est associée principalement aux réseaux routier et de transport d'électricité (respectivement 12,0 % et 39,1 % du total) et ouvre les perspectives de mise à profit des REP à l'implication des propriétaires fonciers privés et communaux.
... A potential contributing factor is the widespread use of pesticides in agriculture and their subsequent dispersal into the environment. In the USA, pesticides have been reported to be the most dominant reason for bird decline (Stanton et al., 2018). A review by Bright et al. (2008), focusing on the UK, concluded that pesticides act mainly through a reduction in food supplies. ...
Article
In spite of meadow bird protection programs, a severe decline of meadow birds is taking place in the Netherlands. It is hypothesized that pesticides and other agrochemicals may contribute to this decline through a negative impact on the entomofauna; a very important food source of meadow birds and especially of their chicks. The present study analysed the presence of 664 pesticides (including biocides and some metabolites) in soil, concentrated feed, manure and some fodder samples from 23 cattle farms in the province of Gelderland (the Netherlands). Furthermore, the presence of 21 anti-parasitic medicines in manure from storage facilities was analysed. For farms practicing field grazing, the number of dung beetles in field samples of fresh manure was determined and a potential relationship with the presence of pesticide residues was explored. Of the 23 farms included in present study, 22 participated in meadow bird protection schemes. A total of 129 different pesticides (including biocides and metabolites) was detected, of which 115 at the 15 conventional farms and 69 at the 8 certified organic farms. The average total amount of pesticide residues detected tended to be lower at organic cattle farms than at conventional farms; for organic concentrated feed this difference was significant at a factor of 3.7. A significant negative correlation was found between the estimated daily intake of insecticides by cattle through the consumption of concentrated feed and hay, and the numbers of dung beetles detected in fresh manure samples in the field. We discuss the most important insecticides detected in concentrated feed and hay, and conclude that their quantities in manure and feed, if compared with LR50 values, give a reason for concern. More research is needed to establish the role of agrochemicals in the decline of meadow birds.
... Knowledge about the status of wild populations is essential for actions aimed at conservation and management of species. The assessment of population trends, i.e. the relative variation of population size over time, allows evaluating whether a population requires conservation attention (Stanton et al., 2018). The estimation of population trends requires a well-defined sampling scheme, where sampling effort and survey methods follow a standardised protocol, which allows the collection of comparable data over time (Gregory et al., 2004;Tucker et al., 2005). ...
Article
The assessment of population trends is a key point in wildlife conservation. Survey data collected over long period may not be comparable due to the presence of environmental biases (i.e. inadequate representation of the variability of environmental covariates in the study area). Moreover, count data may be affected by both overdispersion (i.e. the variance is larger than the mean) and excess of zero counts (potentially leading to zero inflation). The aim of this study was to define a modelling procedure to assess long-term population trends that addressed these three issues and to shed light on the effects of environmental bias, overdispersion, and zero inflation on trend estimates. To test our procedure, we used six bird species whose data were collected in northern Italy from 1992 to 2019. We designed a multi-step approach. First, using generalised additive models (GAMs), we implemented a full factorial design of models (eight models per species) taking or not into account the environmental bias (including or not including environmental covariates, respectively), overdispersion (using a negative binomial distribution or a Poisson distribution, respectively), and zero inflation (using or not using zero-inflated models, respectively). Models were ranked according to the Akaike Information Criterion. Second, annual population indices (median and 95% confidence interval of the number of pairs per point count) were predicted through a parametric bootstrap procedure. Third, long-term population trends were assessed and tested for significance fitting weighted least square linear regression models to the predicted annual indices. To evaluate the effect of environmental bias, overdispersion, and zero inflation on trend estimates, an average discrepancy index was calculated for each model group. The results showed that environmental bias was the most important driver in determining different trend estimates, although overlooking overdispersion and zero inflation could lead to misleading results. For five species, zero-inflated GAMs resulted the best models to predict annual population indices. Our findings suggested a mutual interaction between zero inflation and overdispersion, with overdispersion arising in non-zero-inflated models. Moreover, for species having flocking foraging and/or colonial breeding behaviours, overdispersed and zero-inflated models may be more adequate. In conclusion, properly handling environmental bias, which may affect several data sets coming from long-term monitoring programs, is crucial to obtain reliable estimates of population trends. Furthermore, the extent to which overdispersion and zero inflation may affect trend estimates should be assessed by comparing different models, rather than presumed using statistical assumption.
... The cause of common nighthawk declines are related to the combined interactions and effects of a number of drivers, including widespread and exponential declines in flying insects (Nebel et al. 2010;English et al. 2017); habitat degradation and loss, likely through land-use practices such as agricultural expansion/intensification that reduce natural open areas (Purves 2015;see Jeliazkov et al. 2016;Stanton et al. 2018) and fire suppression (Saab et Powel, 2005;Ruffman 2008;Kalies et al. 2010); as well as an increase in predators such as house cats and crows (Blancher 2013;Latta and Latta 2015;Degregoriao et al. 2016). Given that the species is susceptible to prolonged periods of cold weather in Spring, extreme weather fluctuations due to climate change could also be affecting survival and breeding success (Murphy-Klassen et al. 2005;Rodenhouse et al. 2008). ...
... 6,7 As such, pesticides are considered a necessary tool in the intensification of agriculture in order to meet the world's food demands. [8][9][10] Despite these benefits, excessive use of pesticides on fruits and vegetables to protect them from damage and loss by pests increases pesticide residues in these foods, 11 possibly reaching levels that are toxic to human health, especially if applied without following Good Agricultural Practices (GAPs). 12,13 Pesticide residues should not pose health risks if they are below the threshold of exposure known as Maximum Residue Limits (MRL). ...
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This study assessed concentrations of pesticide residues in fruits and vegetables from farm-to-fork in Kampala Metropolitan Area, Uganda. A total of 160 samples of fruit and vegetables collected from farms, markets, streets, restaurants and homes were analysed using liquid chromatography–tandem mass spectrometry; and Gas Chromatograph–Mass Spectrometer for dithiocarbamates. Multiple pesticide residues were detected in majority of the samples (95.6%). The proportions of the most frequently detected pesticides residue classes were organophosphates (91.3%), carbamates (67.5%), pyrethroids (60.0%) dithiocarbamates (48.1%) and neonicotinoids (42.5%). Among organophosphates, propotamophos, acephate, fonofos, monocrotophos and dichlorvos were the most detected active ingredients; aminocarb, methomyl and pirimicarb were the commonly detected carbamates; while imidacloprid, a neonicotinoid and lambda-cyhalothrin, pyrethroid were also highly detected. Twenty-seven pesticide were tested at all stages, of which the concentrations either decreased or increased along the chain. Multiple pesticide residues occurred in commonly consumed fruit and vegetables with decreasing or increasing concentrations from farm-to-fork.
... In the last century, the rate of biodiversity loss has run at an unprecedented pace (Pievani, 2014;Ceballos et al., 2015). Birds are no exception, especially in agricultural areas (Inger et al., 2015;Stanton, Morrissey & Clark, 2018;Rosenberg et al., 2019). In Europe, 55% of farmland birds showed population declines between 1980 and 2006 (Voříšek et al., 2010). ...
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The last century has seen a steep decline in biodiversity, and anthropization is considered one of the major drivers of this decline. Anthropogenic disturbances, due to human presence and/or activities, may be perceived as chronic stressors by wildlife and potentially lead to deleterious effects on traits related to fitness. The main objective of the present study was to highlight the effects of these anthropogenic elements on wild birds on sparsely urbanized farmland, far less studied than in urbanized areas. We investigated during four successive breeding seasons whether the anthropization level, assessed by infrastructure density around nests, and the harvesting conditions around nests may impact physiological, behavioural and life-history traits of Montagu's harrier Circus pygargus chicks. Higher anthropization levels were associated with higher basal corticosterone levels in nestlings during only one breeding season and a lower body condition at fledging for females, probably because they suffered from higher starvation than males. Nestlings reared in more anthropized areas or in harvested crops before their fledging harboured more fault bars on rectrices than those reared in less anthropized areas or in unhar-vested crops regardless of year and sex, which is suggestive of higher stress during development. Nestling behaviours were also impacted by anthropization level and harvesting conditions: chicks in harvested crops were more aggressive and in areas with higher anthropization levels more prone to escape than others. Because Mon-tagu's harrier is a protected species, the impacts highlighted in the present study are a matter of concern, especially regarding farmland landscape modifications, and we advise limiting perturbations in areas where Montagu's harriers usually nest.
... While highly successful in terms of agricultural productivity, converting prairie ecosystems to farmland has caused loss of soil organic matter and has altered local and regional water and nutrient cycles (Bartzen et al., 2010;Blann et al., 2009;VandenBygaart et al., 2003). Today, declines in indicators of ecosystem health, such as soil quality (Pennock et al., 1994), water quality (Blann et al., 2009;Malaj et al., 2020), and populations of grassland birds (Stanton et al., 2018), can be attributed to tillage, drainage, and application of fertilizers and pesticides-agricultural practices intended to maintain and increase crop productivity, sometimes under the banner of Table 1. Direction of future research exploring ecosystem restoration in the Canadian prairie region in light of insights afforded by the principles of biomimicry. ...
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Ecosystem restoration is proposed as one aspect of the transformative changes required to meet global sustainability goals. In the prairie region of Canada, where the widespread and relatively recent conversion of natural ecosystems to farmland displaced Indigenous peoples and made way for a thriving agricultural sector, I propose that ecosystem restoration requires two intertwined transition processes: reorienting worldviews to embrace the social and biophysical contexts of local ecosystems, and taking practical steps to restore ecosystem functioning and integrity. Attention to ecosystem functioning-the relational processes that undergird the desired outcomes-can promote the design and implementation of agricultural landscapes that mimic key features of natural ecosystems while maintaining a mix of land uses. Human ingenuity and thoughtful integration of traditional and scientific knowledge are needed to develop locally adapted land use that supports synergetic relationships within and among farm fields and other landscape features. Integrating social goals into the design of agricultural landscapes can spawn creative solutions but will require a shift toward a more open and collaborative approach, especially regarding the use of privately owned lands.
... Many bird species are declining more rapidly in agricultural landscapes than other land use types (Stanton et al. 2018, PECBMS 2020. The major reasons for these declines are urbanization, hunting and trade, chemical poisoning, electrocution, agricultural intensification, lack of suitable nesting trees, and varying rainfall patterns or temperature anomalies associated with global climate change (Inskipp and Baral 2010, Mitra et al. 2011, Pearce-Higgins et al. 2015, BirdLife International 2022, Katuwal et al. 2021. ...
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Many threatened birds use the mosaic of agricultural landscapes for foraging and breeding. Despite the reliance of many species on these habitats, few studies have investigated factors influencing the breeding ecology of storks in agricultural landscapes. We assessed site-level variables (tree height and location of nest tree; human habitation or non-human habitation), colony-level variables (colony size and chicks per nest), and landscape-level variables (area of human habitation, wetland area, and distance to the nearest wetland) to understand the factors influencing the breeding ecology of the globally threatened Lesser Adjutant (Leptoptilos javanicus) across multiple locations in the agricultural landscape of lowland Nepal during 2019–2020. We monitored 65 active colonies that had 206 active nests in five study sites. Two hundred eighty chicks fledged from these colonies, with 13% (n = 41) chick mortality. Most colonies were in agricultural land (51%) and human habitation (28%). Lesser Adjutant colonies located on tall trees such as Bombax ceiba (57%), Haldina cordifolia (11%), and Ficus religiosa (11%); however, these tree species were used much more than their availability on the landscape. Tree height had a significant positive influence on colony site selection and colony size, whereas colony size positively influenced fledgling success. Measured landscape variables did not have significant relationships with breeding success metrics. The agricultural landscapes of lowland Nepal provided important breeding habitat for Lesser Adjutants, and the suitability of sites with colonies related more to site-level and colony-level than landscape-level variables. Increasing urban development of agricultural landscapes is likely the greatest threat to breeding Lesser Adjutants, with the decline of suitable nesting trees being a potential additional threat. Lowland Nepal's agricultural landscapes support significant breeding populations of Lesser Adjutants that had considerable breeding success, underscoring the urgent need to support traditional agriculture that favors large waterbirds.
... Analysis of BirdLife International's World Bird Database and North American Breeding Bird Survey data, for example, show that farming is the single greatest risk to threatened bird species [3]. Grasslands, where land can be converted with ease and the pressure to intensify agricultural production is greatest, are additionally vulnerable, along with their species assemblages [4,5]. ...
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Environmental damage caused by the intensification of agriculture may be compensated by implementing conservation projects directed towards reducing threatening processes and conserving threatened native species. In Australia, feral cats (Felis catus) have been a ubiquitous threatening process to Australian fauna since European colonisation. On Shamrock Station, in the north-west of Western Australia, the Argyle Cattle Company has proposed intensifying agriculture through the installation of irrigation pivots. There is concern that irrigating land and storing agricultural produce may indirectly increase the abundance of feral cats and European red foxes (Vulpes vulpes) on the property, which in turn may negatively impact threatened bilbies (Macrotis lagotis) that also inhabit the property. Feral cat control is required under the approved management plan for this project to mitigate this potential impact. Our baseline study revealed a high density of feral cats on Shamrock Station (0.87 cats km−2) and dietary data that suggest the current native mammal assemblage on Shamrock Station is depauperate. Given the high density of feral cats in this area, the effective control of this introduced predator is likely to confer benefits to the bilby and other native species susceptible to cat predation. We recommend ongoing monitoring of both native species and feral cats to determine if there is a benefit in implementing feral cat control around areas of intensive agriculture and associated cattle production.
Chapter
Environmental pollution is a global phenomenon that affects all continents and dozens of types of pollutants with highly different properties can be found on Earth. These pollutants may result in detrimental environmental conditions with clear negative effects on fitness, but they can also induce more pernicious and subtle effects by triggering maladaptive responses to environmental conditions. Importantly, the impact of pollutants on organismal systems is often also exacerbated during the developmental stage. Indeed, developmental conditions are known to affect the ontogeny of multiple integrative organismal systems, and notably the ontogeny of stress-coping mechanisms. These mechanisms involve cognition, the fight or flight response and the HPA axis; they are crucial to consider in the context of pollution because they govern the ability of the individual to adjust to the environmental perturbations that may arise from physical pollutants. In addition, they may also be disrupted by chemical pollutants, resulting in a maladaptive response to environmental conditions and in pathologies. In this chapter, we first provide an example of how developmental exposure to a chemical pollutant (lead, Pb) may disrupt stress-coping mechanisms with detrimental consequences later in life. Then, we illustrate the impact of physical pollutants on performance by focusing on the example of noise pollution. We especially aim to highlight the importance of stress-coping mechanisms and their flexibility in determining the ability of individuals to cope with noise pollution. Finally, we propose several avenues of research to better understand how wild species may adapt to this polluted world. We emphasize (1) the importance of considering the cumulative and interactive effects of physical and chemical pollutants on stress-coping mechanisms and performance; (2) the potential importance of priming hormesis in adjusting the functioning and the flexibility of stress-coping mechanisms to a polluted environment; (3) the need to consider microevolution to assess whether selection acts on stress-coping mechanisms and favors specific stress-coping traits that are beneficial in a polluted world.
Article
Agricultural intensification has led to dramatic declines in bird populations. In particular, the acknowledged role of synthetic pesticides on direct bird intoxication or food resource depletion urges us to seek alternative crop protection methods. Pest exclusion netting systems have recently gained popularity among fruit growers as an efficient means of reducing pest attacks, allowing their transition to organic farming. Single-row exclusion nets, which only cover fruit trees and leave uncovered both the inter-row grassy strips and the hedges, are increasingly being used in apple orchards of Southern Europe. However, net-induced effects on wildlife remain unknown. This study is the first to assess the impacts of single-row exclusion nets on breeding bird communities. We hypothesized that the exclusion net effects would be weaker than those associated with synthetic pesticide use, except for bird species that forage in the tree canopy. We monitored breeding bird abundance, and species richness in 46 commercial apple orchards managed using integrated pest management (IPM) or organic standards with or without exclusion nets. We counted 705 birds belonging to 32 different species. Total bird abundance, the number of observed species, and the Chao1 estimate of species richness were influenced by orchard management strategy. Breeding bird assemblages in organic orchards were as numerous and diverse in both the presence and absence of exclusion nets. In contrast, both bird abundance and species richness were significantly decreased in IPM orchards. The abundance and species richness of bird assemblages and the abundance of a few individual species also increased with the number of hedgerows bordering the orchards. Our results demonstrate that single-row netting systems for organic farming represent an effective pest control strategy with no significant impact on bird communities and highlight the importance of hedgerows along the orchards’ edges.
Article
Hirundo rustica (Barn Swallow) belongs to a suite of aerial insectivores that are showing serious population declines in northeastern North America. Various causes of these declines have been postulated, especially including agricultural intensification, declining insect populations, and/or increased mortality associated with climate changes. In this study, we examined foraging behavior of Barn Swallows nesting in a large breeding colony located in western Massachusetts. Swallows foraged primarily within 1 km of their nesting site. Most of the nearby agricultural areas used by foraging swallows were broadly characterized as pasture/hay or cultivated land uses; we found no significant difference in foraging activity levels between these habitat categories. In addition to the availability of suitable nesting structures, successful conservation of Barn Swallows likely requires that breeding colonies have access to nearby fields which provide foraging opportunities. Further study is needed to clarify specific habitat management that will enhance populations of flying insects preyed upon by swallows and other aerial insectivores.
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Standardized data on large‐scale and long‐term patterns of species richness are critical for understanding the consequences of natural and anthropogenic changes in the environment. The North American Breeding Bird Survey (BBS) is one of the largest and most widely used sources of such data, but so far, little is known about the degree to which BBS data provide accurate estimates of regional richness. Here, we test this question by comparing estimates of regional richness based on BBS data with spatially and temporally matched estimates based on state Breeding Bird Atlases (BBA). We expected that estimates based on BBA data would provide a more complete (and therefore, more accurate) representation of regional richness due to their larger number of observation units and higher sampling effort within the observation units. Our results were only partially consistent with these predictions: while estimates of regional richness based on BBA data were higher than those based on BBS data, estimates of local richness (number of species per observation unit) were higher in BBS data. The latter result is attributed to higher land‐cover heterogeneity in BBS units and higher effectiveness of bird detection (more species are detected per unit time). Interestingly, estimates of regional richness based on BBA blocks were higher than those based on BBS data even when differences in the number of observation units were controlled for. Our analysis indicates that this difference was due to higher compositional turnover between BBA units, probably due to larger differences in habitat conditions between BBA units and a higher likelihood of observing geographically restricted species. Our overall results indicate that estimates of regional richness based on BBS data suffer from incomplete detection of a large number of rare species, and that corrections of these estimates based on standard extrapolation techniques are not sufficient to remove this bias. Future applications of BBS data in ecology and conservation, and in particular, applications in which the representation of rare species is important (e.g., those focusing on biodiversity conservation), should be aware of this bias, and should integrate BBA data whenever possible.
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Across North America, the abundance of many bird populations are declining, in part due to agricultural expansion and intensification. However, there is clear evidence of multiple farming practices that can be beneficial to avian conservation when implemented at field, farm, and landscape scales. These practices will not replace protected areas, but should be seen as part of a coordinated solution to a clear conservation challenge. Moreover, there is now a broader scope and richer evidence of the benefits that birds provide to farms, farmers, and the community. In the future, agricultural landscapes, and the people who manage them, can and should be part of local and regional bird conservation efforts across North America.
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Chemically intensive crop production depletes wildlife food resources, hinders animal development, health, survival, and reproduction, and it suppresses wildlife immune systems, facilitating emergence of infectious diseases with excessive mortality rates. Gut microbiota is crucial for wildlife's response to environmental stressors. Its composition and functionality are sensitive to diet changes and environmental pollution associated with modern crop production. In this study we use shotgun metagenomics (median 8,326,092 sequences/sample) to demonstrate that exposure to modern crop production detrimentally affects cecal microbiota of sharp-tailed grouse (Tympanuchus phasianellus: 9 exposed, 18 unexposed and greater prairie chickens (T. cupido; 11, 11). Exposure to crop production had greater effect on microbiota richness (t = 6.675, P < 0.001) and composition (PERMANOVA r² = 0.212, P = 0.001) than did the host species (t = 4.762, P < 0.001; r² = 0.070, P = 0.001) or their interaction (t = 3.449; r² = 0.072, both P = 0.001), whereas sex and age had no effect. Although microbiota richness was greater in exposed (T. cupido chao1 = 152.8 ± 20.5; T. phasianellus 115.3 ± 17.1) than in unexposed (102.9 ± 15.1 and 101.1 ± 17.2, respectively) birds, some beneficial bacteria dropped out of exposed birds' microbiota or declined and were replaced by potential pathogens. Exposed birds also had higher richness and load of virulome (mean ± standard deviation; T. cupido 24.8 ± 10.0 and 10.1 ± 5.5, respectively; T. phasianellus 13.4 ± 6.8/4.9 ± 2.8) and resistome (T. cupido 46.8 ± 11.7/28.9 ± 10.2, T. phasianellus 38.3 ± 16.7/18.9 ± 14.2) than unexposed birds (T. cupido virulome: 14.2 ± 13.5, 4.5 ± 4.2; T. cupido resistome: 31.6 ± 20.2 and 13.1 ± 12.0; T. phasianellus virulome: 5.2 ± 4.7 and 1.4 ± 1.5; T. phasianellus resistome: 13.7 ± 16.1 and 4.0 ± 6.4).
Article
Aerial insectivores show worldwide population declines coinciding with shifts in agricultural practices. Increasing reliance on certain agricultural practices is thought to have led to an overall reduction in insect abundance that negatively affects aerial insectivore fitness. The relationship between prey availability and the fitness of insectivores may thus vary with the extent of agricultural intensity. It is therefore imperative to quantify the strength and direction of these associations. Here we used data from an 11‐year study monitoring the breeding of Tree Swallows (Tachycineta bicolor) and the availability of Diptera (their main prey) across a gradient of agricultural intensification in southern Québec, Canada. This gradient was characterized by a shift in agricultural production, whereby landscapes composed of forage and pastures represented less agro‐intensive landscapes and those focusing on large‐scale arable row crop monocultures, such as corn (Zea mays) or soybean (Glycine max) that are innately associated with significant mechanization and agro‐chemical inputs, represented more agro‐intensive landscapes. We evaluated the landscape characteristics affecting prey availability, and how this relationship influences the fledging success, duration of the nestling period, fledgling body mass, and wing length as these variables are known to influence the population dynamics of this species. Diptera availability was greatest within predominately forested landscapes, while within landscapes dominated by agriculture, it was marginally greater in less agro‐intensive areas. Of the measured fitness and body condition proxies, both fledging success and nestling body mass were positively related to prey availability. The impact of prey availability varied across the agricultural gradient as fledging success improved with increasing prey levels within forage landscapes yet declined in more agro‐intensive landscapes. Finally, after accounting for prey availability, fledging success was lowest, nestling periods were the longest, and wing length of fledglings were shortest within more agro‐intensive landscapes. Our results highlight the interacting roles that aerial insect availability and agricultural intensification have on the fitness of aerial insectivores, and by extension how food availability may interact with other aspects of breeding habitats to influence the population dynamics of predators.
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Agricultural intensification simplifies natural landscapes and frequently results in the loss of biodiversity. Wetlands are highly productive and may offset these losses, but the amount of wetland area needed to support declining avian species on farmland is unknown. Using an avian aerial insectivore, the Tree Swallow ( Tachycineta bicolor (Vieillot, 1808)), we tested whether a gradient of pond area (visible surface water in wetland basins within 500 m of nest boxes; range 0.2%–30% pond area) at cropland and grassland sites was related to aquatic insect biomass, reproductive success, and adult female or nestling body condition. Aquatic insect biomass was ∼2–8 times higher at the cropland sites with intermediate (5.2%) pond areas than at sites with the highest (15.6%) and lowest (0.2%) pond areas. Swallow clutch initiation date was ∼3–4 days earlier, and nestling body condition and model-predicted first-year survival were ∼10% higher among cropland sites with more pond area and were comparable to birds hatched at grassland sites. Loss of ponds due to agricultural drainage can reduce aquatic insect prey during the breeding season with apparent individual and demographic consequences for insectivorous birds. Overall, the results suggest that where wetlands are conserved, intensive croplands can sustain Tree Swallow populations.
Article
Climate change predicts the increased frequency, duration, and intensity of inclement weather periods, such as unseasonably low temperatures (i.e., cold snaps) and prolonged precipitation. Many migratory species have advanced the phenology of important life history stages, and as a result will likely be exposed to these periods of inclement spring weather more often, thus risking reduced fitness and population growth. For declining avian species, including aerial insectivores, anthropogenic landscape changes such as agricultural intensification are another driver of population declines. These landscape changes may affect the foraging ability of food provisioning parents, and reduce the survival of nestlings exposed to inclement weather, through for example pesticide exposure impairing thermoregulation and punctual anorexia. Breeding in agro‐intensive landscapes may thus exacerbate the negative effects of inclement weather under climate change. We observed that a significant reduction in the availability of insect prey occurred when daily maximum temperatures fell below 18.3°C, and thereby defined any day where the maximum temperature fell below this value as a day witnessing a cold snap. We then combined daily information on the occurrence of cold snaps and measures of precipitation to assess their impact on the fledging success of Tree Swallows (Tachycineta bicolor) occupying a nest box system placed across a gradient of agricultural intensification. Estimated fledging success of this declining aerial insectivore was 36.2% lower for broods experiencing four cold snap days during the 12 days post hatching period versus broods experiencing none, and this relationship was worsened when facing more precipitation. We further found that the overall negative effects of a brood experiencing periods of inclement weather was exacerbated in more agro‐intensive landscapes. Our results indicate that two of the primary hypothesized drivers of many avian population declines may interact to further increase the rate of declines in certain landscape contexts.
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Jankowski’s Bunting Emberiza jankowskii is one of several grassland birds that have suffered major population declines across their ranges, and the cause of these declines remains largely unknown. To determine what demographic drivers are responsible for their decline, we combined specific annual female productivity from a local Jankowski’s Bunting population and survival probabilities from the Ortolan Bunting, an ecologically similar species. We used an age-structured matrix population model to examine the population dynamics of Jankowski’s Bunting and showed that they may not be capable of sustaining a stable population, even without environmental stochasticity and density dependence. Compared to other Emberiza buntings with similar population trends, our results indicate that the population decline in Jankowski’s Bunting is largely caused by a particularly low reproductive success, and in particular a very low survival of eggs and nestlings. Despite the relatively low elasticity of the population dynamics to breeding parameters, our analysis suggests that increasing the number of fledglings to levels similar to those of closely related species would result in a growing population. Given that the reproductive success is highly influenced by nest predation or human disturbance, we suggest that initial conservation actions reducing interference from human activities are meaningful to improve the reproductive success of remaining Jankowski’s Bunting populations and allow the species to persist in the long term.
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Conventional farming has been implicated in global biodiversity loss, with many farmland birds in decline. Organic farming is often considered a more ecological alternative since it generally hosts greater faunal diversity. To date, the impact of conventional agriculture on the decline in avian species has mainly been assessed through the lens of biodiversity loss; few studies have examined the effects of conventional farming on individual life-history trait components. Behaviour represents the final integrated outcome of a range of biochemical and physiological pathways and can be considered a proxy of health as it is more sensitive than other life-history traits, potentially allowing environmental changes to be better tracked. The goal of this study was to understand how exposure to conventional versus organic farming affects the behaviour of passerine birds in real conditions. By sampling 6 species of passerine birds in 10 hedgerows in organic landscapes and 10 hedgerows in conventional landscapes during the breeding period, we found evidence that organic farming sharply increased the vitality of individuals, irrespective of species. This was measured through behaviour such as flee attempts, aggressivity, pecking and distress calls when captured, all of which were higher in birds caught in organic hedges than those caught in conventional landscapes. We posit that passerines living in organically farmed landscapes benefit from reduced pesticide exposure rather than a greater abundance of food, as body condition was identical in the two contexts. These findings suggest that the behaviour of passerines can be a useful indicator of the state of the environment and can thus serve as an early warning of specific environmental change in agricultural areas. Further studies assessing the life-history traits of farmland birds may be a valuable aid to understanding the impact of conventional agriculture on biodiversity.
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This article is brought to you by the SPARC Initiative created in partnership between the American Society for Agronomy, the Agricultural Retailers Association, Environmental Defense Fund, and Field to Market: The Alliance for Sustainable Agriculture to empower trusted advisers to deliver services that drive continuous improvement in the productivity, profitability, and environmental outcomes of farmers’ operations. Learn more about the SPARC Initiative and access additional resources, including the six‐module series on sustainability at www.fieldtomarket.org/SPARC. This article is an excerpt from Field to Market’s Fourth National Indicators Report, released in December 2021. Access the entire report at www.fieldtomarket.org/report. Sections covering soil carbon and water quality will be included in future issues of Crops & Soils magazine. Earn 1 CEU in Sustainability by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.
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The decline of avian aerial insectivores has been greater than any other foraging guild and both climate change and agricultural intensification are leading hypotheses explaining this decline. Spring cold snaps are predicted to increase in frequency due to climate change, and factors associated with agricultural intensification (e.g., toxicological agents, simplification of agricultural landscapes, and reductions of insect prey) potentially exacerbates the negative effects of cold snaps on aerial insectivore nestling growth and body condition. We evaluated this hypothesis using repeated measures of Tree Swallow (Tachycineta bicolor (Vieillot, 1808)) nestling body mass and 9th primary length across an expansive gradient of agricultural intensification. Growth rate, asymptotic body mass, and near fledging 9th primary length were lower for nestlings in landscapes consisting of more agro-intensive monocultures. This 14-year data set of body measures occurring at 2, 6, 12 and 16 days of age showed that the negative impact of cold snaps on the growth of these two traits was stronger for nestlings reared in more agro-intensive landscapes. Our findings provide further evidence that two of the primary hypothesized drivers for the decline of many aerial insectivores may interact and aggravate their decline by reducing fledging survival.
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Background Individual and environmental health outcomes are frequently linked to changes in the diversity of associated microbial communities. Thus, deriving health indicators based on microbiome diversity measures is essential. While microbiome data generated using high-throughput 16S rRNA marker gene surveys are appealing for this purpose, 16S surveys also generate a plethora of spurious microbial taxa. Results When this artificial inflation in the observed number of taxa is ignored, we find that changes in the abundance of detected taxa confound current methods for inferring differences in richness. Experimental evidence, theory-guided exploratory data analyses, and existing literature support the conclusion that most sub-genus discoveries are spurious artifacts of clustering 16S sequencing reads. We proceed to model a 16S survey’s systematic patterns of sub-genus taxa generation as a function of genus abundance to derive a robust control for false taxa accumulation. These controls unlock classical regression approaches for highly flexible differential richness inference at various levels of the surveyed microbial assemblage: from sample groups to specific taxa collections. The proposed methodology for differential richness inference is available through an R package, Prokounter . Conclusions False species discoveries bias richness estimation and confound differential richness inference. In the case of 16S microbiome surveys, supporting evidence indicate that most sub-genus taxa are spurious. Based on this finding, a flexible method is proposed and is shown to overcome the confounding problem noted with current approaches for differential richness inference. Package availability: https://github.com/mskb01/prokounter
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Farmland harbors valuable biodiversity, providing habitats and associated resources for birds. However, environmental change is affecting the habitat availability within agricultural landscapes. Thus, conserving farmland areas that have the potential to provide habitats for birds is increasingly considered to mitigate pressure on ecological systems. Incorporating these concerns into bird habitat analysis to aid in conservation actions is needed to assist policy developers in protecting bird habitats in Taiwan efficiently. In the present study, we propose combining an expert-based approach with empirical data to develop an evaluation of bird habitat suitability on farmlands. Experts were initially gathered to construct a research framework and then express their judgments on ecological factors. We obtained the significant factors such as farmland fragmentation, farmland landscape heterogeneity, and distance to surrounding vegetation within fifteen evaluated sub-criteria under four criteria of farmland functionality, farmland utilization, farmland located within a major conservation area, and farmland landscape ecology as the habitat requirements of birds. Combing the weight-based priority and empirical data, we finally determined a highly suitable habitat for birds accounting for 31.92% of farmlands. In an assessment involving bird distribution records in the study area, the accuracy derived from model validation is 91.25%. The findings of this work can provide authorities and policymakers with potential hotspots for ecosystem conservation.
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Neonicotinoid insecticides (NENIs) have become increasingly common in recent decades in the control of crop pests and other plant pathogens. It is undeniable that the practice improves crop yield and economic productivity in agriculture in general. However, the ongoing use of these chemicals in modern agriculture, as well as their widespread occurrence in the environment, poses a significant threat to food quality as well as safety, potentially posing a health risk to the public. This paper presents a comprehensive review of the latest explorations of NENIs based on extensive scientific collections to illustrate their distribution in soil, surface waters, and groundwater; discuss their exposure risk and potential toxic effects on the environment. It also highlights the connections between NENIs usage and their footprint on natural resources and the major food chains involving plants, animals, and humans. Web of Science, Google Scholar, PubMed, Science Direct, and other web sources were searched for scientific literature on NENIs distribution, properties, usage, cycling, and intrusion in the environment and food chain covering the last 14 years (2008 – 2022). A significant portion of available literature indicates an exponential increase in the use of NENIs within the last decade, and the large body of data shows that these group of insecticides pose substantial risks to the environment, humans, and other non-target living species. Here, the current state of knowledge, sources, environmental distribution, and the health effects of NENIs for soil organisms, plants, birds, animals, humans, and other non-target organisms are discussed. However, a great deal of information is still lacking, including NENIs threshold levels in soil, aquatic, terrestrial resources, and living organisms. Thus, a global multidisciplinary research effort is necessary to fill the existing knowledge gap, particularly related to NENIs toxic effects on the ecosystem. The review article will interest a wide range of stakeholders, from soil and water scientists to conservationists to academics and researchers.
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The historical rise of intensive agricultural practices is hypothesized to be related to declines of grassland and aerial insectivorous birds. Drivers of declines may also influence the overall abundance and spatial distribution of insects within agricultural landscapes. Subsequently, the food provisioning rate of birds breeding within more agro‐intensive landscapes may be impacted. Lower provisioning rates in agro‐intensive landscapes may lead not only to reduced growth rate, body condition, or fledging success of nestlings but also to diminished body condition of food provisioning adults. Results from a previous study supported this hypothesis as the fledging success and proxies of nestling body condition were lowest for an aerial insectivore breeding in more agro‐intensive landscapes. Of the multiple hypotheses put forward to explain these correlations, one mechanism may act through variation in food provisioning rates. In this study, we expounded on this hypothesis using data derived from the aforementioned study system and assessed if provisioning rates to nestlings and food provisioning behavior of adults varied across a gradient of agricultural intensification in a declining aerial insectivore, the Tree Swallow (Tachycineta bicolor). We found that the hourly provisioning rate was lower in agro‐intensive landscapes, and yet travel distances were longest within less agro‐intensive landscapes. Our results highlight that, in order to maximize long‐term average gain rates, Tree Swallows breeding within agro‐intensive landscapes must forage with greater intensity, perhaps at a cost to themselves, or else costs will transfer to growing broods. Our work provides further evidence that agricultural intensification on the breeding grounds can contribute to the declines of aerial insectivores in part through a trophic pathway.
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Intensification of agricultural systems and increased insecticide use have been implicated in global losses of farmland biodiversity and ecosystem services. We hypothesized that increased insecticide applications (proportion of area treated with insecticides) in Canada's expansive agricultural landscapes are due, in part, to shifts toward more simplified landscapes. To assess this relationship, we analyzed data from the Canadian Census of Agriculture spanning 20 years and five censuses (1996-2016) and across 225 census units within four major agricultural regions of Pacific, Prairie, Central and Atlantic Canada. Generalized mixed effect models were used to evaluate if changes in landscape simplification - defined as the proportion of farmland in crops (cereals, oilseeds, pulses and vegetables) - alongside other farming and climatic variables, influenced insecticide applications over time. Bayesian spatial-temporal models were further used to estimate the strength of the relationship with landscape simplification over time. We found that landscape simplification increased in 89% and insecticide applications increased in 70% of the census division spatial units over the 1996-2016 period. Nationally, significant increases in landscape simplification were observed in the two most agriculturally intensive regions of Prairie (from 55 to 63%) and Central (from 51 to 60%) Canada. For both regions, landscape simplification was a strong and significant predictor of higher insecticide applications, even after accounting for important factors such as climate, economics, farm size and land use practices (e.g., area in cash crops and tillage). If current trends continue, we estimated that insecticide applications will increase 10-20% by 2036 as a result of landscape simplification alone. To avoid increased reliance on toxic insecticides, agri-environmental policies need to consider that losing diverse natural habitat can increase insect pest pressure and resistance with negative environmental consequences extending beyond the field.
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Birds that travel long distances between their wintering and breeding grounds may be particularly susceptible to neurotoxic insecticides, but the influence of insecticides on migration ability is poorly understood. Following acute exposure to two widely used agricultural insecticides, imidacloprid (neonicotinoid) and chlorpyrifos (organophosphate), we compared effects on body mass, migratory activity and orientation in a seed-eating bird, the white-crowned sparrow (Zonotrichia leucophrys). During spring migration, sparrows were captured, held and dosed by gavage daily for 3 days with either the vehicle control, low (10% LD50) or high (25% LD50) doses of imidacloprid or chlorpyrifos and tested in migratory orientation trials pre-exposure, post-exposure and during recovery. Control birds maintained body mass and a seasonally appropriate northward orientation throughout the experiment. Imidacloprid dosed birds exhibited significant declines in fat stores and body mass (mean loss: −17% low, −25% high dose) and failed to orient correctly. Chlorpyrifos had no overt effects on mass but significantly impaired orientation. These results suggest that wild songbirds consuming the equivalent of just four imidacloprid-treated canola seeds or eight chlorpyrifos granules per day over 3 days could suffer impaired condition, migration delays and improper migratory direction, which could lead to increased risk of mortality or lost breeding opportunity.
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Loss of biodiversity and degradation of ecosystem services from agricultural lands remain important challenges in the United States despite decades of spending on natural resource management. To date, conservation investment has emphasized engineering practices or vegetative strategies centered on monocultural plantings of nonnative plants, largely excluding native species from cropland. In a catchment-scale experiment, we quantified the multiple effects of integrating strips of native prairie species amid corn and soybean crops, with prairie strips arranged to arrest run-off on slopes. Replacing 10% of cropland with prairie strips increased biodiversity and ecosystem services with minimal impacts on crop production. Compared with catchments containing only crops, integrating prairie strips into cropland led to greater catchment-level insect taxa richness (2.6-fold), pollinator abundance (3.5-fold), native bird species richness (2.1-fold), and abundance of bird species of greatest conservation need (2.1-fold). Use of prairie strips also reduced total water runoff from catchments by 37%, resulting in retention of 20 times more soil and 4.3 times more phosphorus. Corn and soybean yields for catchments with prairie strips decreased only by the amount of the area taken out of crop production. Social survey results indicated demand among both farming and nonfarming populations for the environmental outcomes produced by prairie strips. If federal and state policies were aligned to promote prairie strips, the practice would be applicable to 3.9 million ha of cropland in Iowa alone.
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Global climate change is a major threat to biodiversity. Large-scale analyses have generally focused on the impacts of climate change on the geographic ranges of species and on phenology, the timing of ecological phenomena. We used long-term monitoring of the abundance of breeding birds across Europe and the United States to produce, for both regions, composite population indices for two groups of species: those for which climate suitability has been either improving or declining since 1980. The ratio of these composite indices, the climate impact indicator (CII), reflects the divergent fates of species favored or disadvantaged by climate change. The trend in CII is positive and similar in the two regions. On both continents, interspecific and spatial variation in population abundance trends are well predicted by climate suitability trends.
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In the northeastern United States, grassland birds regularly use agricultural fields as nesting habitat. However, birds that nest in these fields regularly experience nest failure as a result of agricultural practices, such as mowing and grazing. Therefore, information on both spatial and temporal patterns of habitat use is needed to effectively manage these species. We addressed these complex habitat use patterns by conducting point counts during three time intervals between May 21, 2002 and July 2, 2002 in agricultural fields across the Champlain Valley in Vermont and New York. Early in the breeding season, Bobolinks (Dolichonyx oryzivorus) used fields in which the landscape within 2500 m was dominated by open habitats. As mowing began, suitable habitat within 500 m became more important. Savannah Sparrows (Passerculus sandwichensis) initially used fields that contained a high proportion of suitable habitat within 500 m. After mowing, features of the field (i.e., size and amount of woody edge) became more important. Each species responded differently to mowing: Savannah Sparrows were equally abundant in mowed and uncut fields, whereas Bobolinks were more abundant in uncut fields. In agricultural areas in the Northeast, large areas (2000 ha) that are mostly nonforested and undeveloped should be targeted for conservation. Within large open areas, smaller patches (80 ha) should be maintained as high-quality, late-cut grassland habitat.
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Many animal species exhibit spatiotemporal synchrony in population fluctuations, which may provide crucial information about ecological processes driving population change. We examined spatial synchrony and concordance among population trajectories of five aerial insectivorous bird species: Chimney Swift (Chaetura pelagica), Purple Martin (Progne subis), Barn Swallow (Hirundo rustica), Tree Swallow (Tachycineta bicolor), and Northern Rough-winged Swallow (Stelgidopteryx serripennis). Aerial insectivores have undergone severe guild-wide declines that were considered more prevalent in northeastern North America. Here, we addressed four general questions including spatial synchrony within species, spatial concordance among species, frequency of declining trends among species, and geographic location of declining trends. We used dynamic factor analysis to identify large-scale common trends underlying stratum-specific annual indices for each species, representing population trajectories shared by spatially synchronous populations, from 46 years of North American Breeding Bird Survey data. Indices were derived from Bayesian hierarchical models with continuous autoregressive spatial structures. Stratum-level spatial concordance among species was assessed using cross-correlation analysis. Probability of long-term declining trends was compared among species using Bayesian generalized linear models. Chimney Swifts exhibited declining trends throughout North America, with less severe declines through the industrialized Mid-Atlantic and Great Lakes regions. Northern Rough-winged Swallows exhibited declining trends throughout the west. Spatial concordance among species was limited, the proportion of declining trends varied among species, and contrary to previous reports, declining trends were not more prevalent in the northeast. Purple Martins, Barn Swallows, and Tree Swallows exhibited synchrony across smaller spatial scales. The extensive within-species synchrony and limited concordance suggest that population trajectories of these aerial insectivores are responding to large-scale but complex and species- and region-specific environmental conditions (e.g., climate, land use). A single driver of trends for aerial insectivores as a guild appears unlikely.This article is protected by copyright. All rights reserved.
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We reviewed cases of raptor mortality resulting from cholinesterase-inhibiting pesticides. We compiled records from the U.S., U.K. and Canada for the period 1985-95 (520 incidents) and surveyed the relevant literature to identify the main routes of exposure and those products that led to the greatest number of poisoning cases. A high proportion of cases in the U.K. resulted from abusive uses of pes- ticides (willful poisoning). The proportion was smaller in North America where problems with labeled uses of pesticides were as frequent as abuse cases. Poisoning resulting from labeled use was possible with a large number of granular pesticides and some seed treatments through secondary poisoning or through the ingestion of contaminated invertebrates, notably earthworms. With the more toxic products, residue levels in freshly-sprayed insects were high enough to cause mortality. The use of organophos- phorus products as avicides and for the topical treatment of livestock appeared to be common routes of intoxication. The use of insecticides in dormant oils also gave rise to exposure that can be lethal or
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A B S T R A C T Many studies have established that birds may provide a pest removal service on farms, although few studies have taken place in temperate row crop agriculture. Wildlife-friendly agricultural practices such as organic farming and the use of hedgerows can in turn provide needed habitat for birds in developed landscapes. In this study, we examined how pest removal provided by birds varies within and between " wildlife-friendly " organic row-crop farms in northern California, USA. We used point counts to assess bird diversity on 29 small organic farms and simulated lepidopteran pest outbreaks on each farm using sentinel pest experiments. We measured how the probability of pest removal varied with local habitat characteristics within the farm, and with bird diversity parameters between farms. We also used exclosure experiments to determine whether birds provide a significant pest removal service in organic row-crop agriculture. In the sentinel pest experiments, birds depredated between 0 and 80% of caterpillar presentation stations within 7 h, with a mean of 24% depredation per farm; the probability of pest removal was higher in areas close to uncultivated shrubby field margins (" hedgerows "). There was only weak evidence that the probability of pest removal was higher on farms with higher avian insectivore richness, and no evidence that pest removal varied with species diversity or abundance. Exclosure experiments on kale crops showed no significant effects of bird exclosure treatment on arthropod abundance or crop yield. However, natural caterpillar densities were relatively low during the exclosure experiment (approximately one caterpillar/m 2). These results suggest that birds may be more helpful in responding to pest outbreaks than in controlling pests at non-irruptive densities on organic row crop farms in this study system. The prevention of pest outbreaks is an essential ecosystem service on any farm, and the rapid response of birds to pest outbreak conditions is an indicator of resiliency in the agroecosystem. Therefore, the retention of uncultivated shrubby field margins in this system may benefit both birds and farmers.
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Grasslands cover more than 40% of Earth's land surface and are the most converted, yet least protected, biome worldwide (Hoekstra et al. 2005). As a guild, grassland birds have declined more rapidly than birds of any other habitat type in North America (Herkert 1995). These statistics might be expected to generate a lot of attention to conservation in this biome; however, just as ignorance about one of the most strident prairie birds gave rise to its scientific name, Sturnella neglecta (Audubon 1840), knowledge regarding the ecology and conservation of grasslands and grassland birds lags behind that of other ecosystems. For example, a search of ISI Web of Knowledge® research turned up less than one third the number of papers about grassland (1445) as forest (5200) birds. Given that 30% of Earth's surface is forested, but 40% is, or was, grassland, per unit area, almost five times more research has been reported about forest birds compared with grassland birds. Perhaps it is little wonder, then, that attributes of species' natural histories, such as territory size of Vesper Sparrows (Pooecetes gramineus; Jones and Cornelys 2002), remain unknown or uncertain.
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Throughout North America, many species of aerial insectivorous birds have exhibited steep declines. The timing of these declines coincides with changes in agriculture, perhaps signaling a causal link. Increased agrochemical use, wetland drainage, and cropping intensity may indirectly influence insectivores by reducing the abundance of insect prey. Our objective was to determine whether changes in insect abundance and biomass on agricultural landscapes in the Canadian Prairies influence the foraging behaviour of breeding Tree Swallows (Tachycineta bicolor (Vieillot, 1808)). Swallows were studied at five sites with varying levels of agricultural intensity in Saskatchewan, where insect abundance and biomass were monitored daily with passive aerial samplers. Radio-frequency identification (RFID) technology was employed at Tree Swallow nest boxes to investigate adult foraging behaviour. Foraging rates (number of nest visits/h) were slightly higher on agricultural sites than at grassland sites, and were positively related to daily insect biomass and nestling age. Tree Swallows, especially males, breeding at agricultural sites spent more time away from the nest box, presumably foraging, resulting in reduced nest attentiveness. RFID technology provides an effective technique to measure behaviour in birds and these findings suggest mechanisms by which prey abundance and agricultural land use may affect declining aerial insectivorous bird populations.
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Vegetation typical of the tallgrass prairie occurs east of the Great Plains in bottomland “openings” and as small “glades” or “balds” within the eastern deciduous forest. West of the Mississippi River, however, coverage by tallgrass prairie expands with the increasingly greater aridity under the deepening rainshadow of the western mountains. Along the Kansas-Missouri border on the western fringe of the deciduous forest, prairie is present across 50–80% of the region (Schroeder 1983). Forested area within this prairie-forest mosaic continues to diminish, decreasing to as little as 7% in the Flint Hills Uplands (Knight et al. 1994). The portion of the Great Plains characterized by the tallgrass prairie community exists in a climate that allows the development of forest as a bordering “gallery” along stream courses. These naturally occurring forest fragments, these island remnants of the continental forest to the east, remain an integral aspect of the tallgrass prairie landscape, contributing a disproportionately greater component, considering the small extent of their coverage, to the regional avian species richness (Faanes 1984, Zimmerman 1993).
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Past projections of conservation tillage adoption are briefly reviewed. Also discussed is the definition used by the US Department of Agriculture in its 1975 projection and how the definition has changed. Previous Soil Conservation Service acreage estimates of conservation tillage, beginning in 1968, are discounted in an attempt to better reflect today's definition. The 1968 discounted figure is then used in an S-shaped adoption curve, under given assumptions, to make an upper and lower projection of conservation tillage. This projection indicates that conservatio