ABSTRACT An understanding of how tropical bird communities might respond to climate change and other types of environmental stressors seems particularly urgent, yet we still lack, except for a few sites, even snapshot inventories of avian richness and abundances across most of the tropics. Such benchmark measurements of tropical bird species richness and abundances could provide opportunities for future repeat surveys and, therefore, strong insight into degrees and pace of change in community organization over time. The challenges of creating a network of benchmarked sites include high variation in detectability among species, general rarity of many species that creates hurdles for use of modern bird counting methods aimed at controlling for variation in detectability, and lack of a standardized protocol to create repeatable inventories. We argue that reasonably complete inventories of tropical bird communities require use of multiple survey techniques to provide internal calibrations of abundance estimates and require multiple visits to improve completeness of richness inventories. We suggest that a network of large (50–100 ha) plots scattered across the tropics can also provide insights into geographic variation in and drivers of avian community structure analogous to insights provided by the Smithsonian Center for Tropical Forest Science Forest Global Earth Observatory network of forest dynamics plots. Perhaps most importantly, large plots provide opportunities for use of multiple survey techniques to estimate abundances while also using some exactly repeatable survey techniques that can greatly improve abilities to quantify change over time. We provide guidance on establishment of and survey methods for large tropical bird plots as well as important recommendations for collection and archiving of metadata to safeguard the long-term utility of valuable benchmark data.
{"title":"Creating benchmark measurements of tropical forest bird communities in large plots","authors":"W. Robinson, J. Curtis","doi":"10.1093/condor/duaa015","DOIUrl":"https://doi.org/10.1093/condor/duaa015","url":null,"abstract":"ABSTRACT An understanding of how tropical bird communities might respond to climate change and other types of environmental stressors seems particularly urgent, yet we still lack, except for a few sites, even snapshot inventories of avian richness and abundances across most of the tropics. Such benchmark measurements of tropical bird species richness and abundances could provide opportunities for future repeat surveys and, therefore, strong insight into degrees and pace of change in community organization over time. The challenges of creating a network of benchmarked sites include high variation in detectability among species, general rarity of many species that creates hurdles for use of modern bird counting methods aimed at controlling for variation in detectability, and lack of a standardized protocol to create repeatable inventories. We argue that reasonably complete inventories of tropical bird communities require use of multiple survey techniques to provide internal calibrations of abundance estimates and require multiple visits to improve completeness of richness inventories. We suggest that a network of large (50–100 ha) plots scattered across the tropics can also provide insights into geographic variation in and drivers of avian community structure analogous to insights provided by the Smithsonian Center for Tropical Forest Science Forest Global Earth Observatory network of forest dynamics plots. Perhaps most importantly, large plots provide opportunities for use of multiple survey techniques to estimate abundances while also using some exactly repeatable survey techniques that can greatly improve abilities to quantify change over time. We provide guidance on establishment of and survey methods for large tropical bird plots as well as important recommendations for collection and archiving of metadata to safeguard the long-term utility of valuable benchmark data.","PeriodicalId":50624,"journal":{"name":"Condor","volume":"122 1","pages":"1 - 15"},"PeriodicalIF":2.4,"publicationDate":"2020-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41328674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT The Millennium Ecosystem Assessment described 4 classes of services or functions that ecosystems and their component parts deliver to the benefit of humans: provisioning, regulating, supporting, and cultural services. Birds, including Neotropical birds, provide a diverse array of services in all 4 classes. We review the literature describing ecosystem services provided by Neotropical birds, draw inference from studies of avian services in other regions when Neotropical studies are limited, and identify key information gaps. Neotropical birds provide provisioning services in the form of meat and eggs for food, and feathers for down and ornamentation. Regulating services are among the most valuable services provided by Neotropical birds, including pollination, pest control, seed dispersal, and scavenging. Neotropical birds also provide supporting services in the form of nutrient cycling, such as through the deposition of guano on offshore islands. Finally, Neotropical birds provide cultural services as pets (caged birds), sources of recreation (e.g., birdwatching, hunting), as well as by inspiring art, photography, and religious customs. Much remains to be learned about the ecology and natural history of many Neotropical birds before we can fully assign value—monetary, nonmaterial, or otherwise—to the services they provide. However, what we have learned to date makes it clear that humans benefit from birds through multiple services, including but not limited to pest reduction, pollination of some agricultural plants, and seed dispersal.
{"title":"Ecosystem services provided by Neotropical birds","authors":"N. Michel, C. Whelan, Gregory M. Verutes","doi":"10.1093/condor/duaa022","DOIUrl":"https://doi.org/10.1093/condor/duaa022","url":null,"abstract":"ABSTRACT The Millennium Ecosystem Assessment described 4 classes of services or functions that ecosystems and their component parts deliver to the benefit of humans: provisioning, regulating, supporting, and cultural services. Birds, including Neotropical birds, provide a diverse array of services in all 4 classes. We review the literature describing ecosystem services provided by Neotropical birds, draw inference from studies of avian services in other regions when Neotropical studies are limited, and identify key information gaps. Neotropical birds provide provisioning services in the form of meat and eggs for food, and feathers for down and ornamentation. Regulating services are among the most valuable services provided by Neotropical birds, including pollination, pest control, seed dispersal, and scavenging. Neotropical birds also provide supporting services in the form of nutrient cycling, such as through the deposition of guano on offshore islands. Finally, Neotropical birds provide cultural services as pets (caged birds), sources of recreation (e.g., birdwatching, hunting), as well as by inspiring art, photography, and religious customs. Much remains to be learned about the ecology and natural history of many Neotropical birds before we can fully assign value—monetary, nonmaterial, or otherwise—to the services they provide. However, what we have learned to date makes it clear that humans benefit from birds through multiple services, including but not limited to pest reduction, pollination of some agricultural plants, and seed dispersal.","PeriodicalId":50624,"journal":{"name":"Condor","volume":"122 1","pages":"1 - 21"},"PeriodicalIF":2.4,"publicationDate":"2020-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43903247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kyle A. Lima, E. Call, T. Hodgman, D. Potter, S. Gallo, Erik J. Blomberg
ABSTRACT Owls play crucial roles in the environment and provide ecosystem services making them important to monitor and study. However, standardized methods for most species do not exist, and we lack understanding of the effects of many environmental variables and call-broadcast on detection of owls during surveys. We performed a multispecies occupancy analysis of owl monitoring data collected from 2004 to 2013 across the state of Maine to examine the effects of environmental variables, conspecific and heterospecific call-broadcast, and general survey protocols on detection of 3 forest owls: Northern Saw-whet Owl (Aegolius acadicus), Barred Owl (Strix varia), and Great Horned Owl (Bubo virginianus). We found that environmental variables such as cloud cover, precipitation, temperature, time of night, and wind had species-specific effects on detection probability, and ambient noise decreased detection probability for all species. Snow cover did not affect detection of any species. We also found that conspecific call-broadcast increased detection of each species, while heterospecific call-broadcast had variable effects. Specifically, we found that Long-eared and Barred owl broadcast increased the detection of Northern Saw-whet Owl, and our results suggest additional heterospecific effects may exist. Our study showed that, compared to the protocol of the Maine Owl Monitoring Program, surveys simultaneously examining all 3 of our focal species can increase efficiency and lower disturbance by only broadcasting Long-eared and Barred owl calls during a 10-min survey. We recommend that future owl surveys take into account species-specific effects of conspecific and heterospecific call-broadcast, and use our results when designing survey protocols that include one or more of our focal species.
{"title":"Environmental conditions and call-broadcast influence detection of eastern forest owls during standardized surveys","authors":"Kyle A. Lima, E. Call, T. Hodgman, D. Potter, S. Gallo, Erik J. Blomberg","doi":"10.1093/condor/duaa016","DOIUrl":"https://doi.org/10.1093/condor/duaa016","url":null,"abstract":"ABSTRACT Owls play crucial roles in the environment and provide ecosystem services making them important to monitor and study. However, standardized methods for most species do not exist, and we lack understanding of the effects of many environmental variables and call-broadcast on detection of owls during surveys. We performed a multispecies occupancy analysis of owl monitoring data collected from 2004 to 2013 across the state of Maine to examine the effects of environmental variables, conspecific and heterospecific call-broadcast, and general survey protocols on detection of 3 forest owls: Northern Saw-whet Owl (Aegolius acadicus), Barred Owl (Strix varia), and Great Horned Owl (Bubo virginianus). We found that environmental variables such as cloud cover, precipitation, temperature, time of night, and wind had species-specific effects on detection probability, and ambient noise decreased detection probability for all species. Snow cover did not affect detection of any species. We also found that conspecific call-broadcast increased detection of each species, while heterospecific call-broadcast had variable effects. Specifically, we found that Long-eared and Barred owl broadcast increased the detection of Northern Saw-whet Owl, and our results suggest additional heterospecific effects may exist. Our study showed that, compared to the protocol of the Maine Owl Monitoring Program, surveys simultaneously examining all 3 of our focal species can increase efficiency and lower disturbance by only broadcasting Long-eared and Barred owl calls during a 10-min survey. We recommend that future owl surveys take into account species-specific effects of conspecific and heterospecific call-broadcast, and use our results when designing survey protocols that include one or more of our focal species.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 20"},"PeriodicalIF":2.4,"publicationDate":"2020-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47613987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT For decades, ecologists have studied fundamental questions of how Amazonian biodiversity is maintained, and whether that diversity can persist following deforestation. The long history of avian research at the Biological Dynamics of Forest Fragments Project, near Manaus, Brazil, has helped advance this understanding in the context of a broader research program focused on rainforest fragments embedded in a dynamic matrix. By sampling birds beginning before fragments were isolated, in the late 1970s, and continuing the protocol to the present, our work has revealed community dynamics driven not just by area and isolation, but also by larger landscape patterns, particularly second growth recovery over decadal scales. Fragments permanently lose some bird species, but their communities need not follow a trajectory toward catastrophic change. Our challenge now is to determine under what conditions remnant patches and developing second growth can support not just the rich diversity of Amazonian rainforest species but also their population processes and emergent community properties.
{"title":"Birds in fragmented Amazonian rainforest: Lessons from 40 years at the Biological Dynamics of Forest Fragments Project","authors":"P. Stouffer","doi":"10.1093/condor/duaa005","DOIUrl":"https://doi.org/10.1093/condor/duaa005","url":null,"abstract":"ABSTRACT For decades, ecologists have studied fundamental questions of how Amazonian biodiversity is maintained, and whether that diversity can persist following deforestation. The long history of avian research at the Biological Dynamics of Forest Fragments Project, near Manaus, Brazil, has helped advance this understanding in the context of a broader research program focused on rainforest fragments embedded in a dynamic matrix. By sampling birds beginning before fragments were isolated, in the late 1970s, and continuing the protocol to the present, our work has revealed community dynamics driven not just by area and isolation, but also by larger landscape patterns, particularly second growth recovery over decadal scales. Fragments permanently lose some bird species, but their communities need not follow a trajectory toward catastrophic change. Our challenge now is to determine under what conditions remnant patches and developing second growth can support not just the rich diversity of Amazonian rainforest species but also their population processes and emergent community properties.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 15"},"PeriodicalIF":2.4,"publicationDate":"2020-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41930775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ana M. González, Scott Wilson, Nicholas J. Bayly, K. Hobson
ABSTRACT In the Neotropics, coffee production occurs on a large scale in some of the planet′s most biodiverse regions: tropical mountains. Coffee production systems involving shade trees are considered to have a lower impact on biodiversity than alternative sun coffee. To date, the majority of evidence for the value of shade coffee plantations has not taken into account the relative quality of this habitat compared to the native forests they replaced. We determined the suitability of shade coffee and forest as winter habitat for Canada Warbler (Cardellina canadensis) by comparing variation in the likelihood of capturing individuals, seasonal changes in body condition, and estimates of annual survival between the 2 habitats. We also determined the effect of the strong 2015–2016 El Niño event on survival. Males were relatively more likely to be captured in forest than females and this likelihood increased during drier years. Body condition change over the winter and apparent annual survival were similar for individuals that used forest and coffee. However, condition and survival decreased in both habitats during the El Niño year. Apparent survival was also lower for individuals carrying a radiotag or geolocator. Our findings suggest that shade coffee with high canopy cover and height offers similar benefits to forest in terms of body condition and survival. Landscape conservation approaches, promoting diverse matrices of structurally complex shade coffee and forest might best ensure long-term survival in Neotropical migrants like Canada Warbler.
{"title":"Contrasting the suitability of shade coffee agriculture and native forest as overwinter habitat for Canada Warbler (Cardellina canadensis) in the Colombian Andes","authors":"Ana M. González, Scott Wilson, Nicholas J. Bayly, K. Hobson","doi":"10.1093/condor/duaa011","DOIUrl":"https://doi.org/10.1093/condor/duaa011","url":null,"abstract":"ABSTRACT In the Neotropics, coffee production occurs on a large scale in some of the planet′s most biodiverse regions: tropical mountains. Coffee production systems involving shade trees are considered to have a lower impact on biodiversity than alternative sun coffee. To date, the majority of evidence for the value of shade coffee plantations has not taken into account the relative quality of this habitat compared to the native forests they replaced. We determined the suitability of shade coffee and forest as winter habitat for Canada Warbler (Cardellina canadensis) by comparing variation in the likelihood of capturing individuals, seasonal changes in body condition, and estimates of annual survival between the 2 habitats. We also determined the effect of the strong 2015–2016 El Niño event on survival. Males were relatively more likely to be captured in forest than females and this likelihood increased during drier years. Body condition change over the winter and apparent annual survival were similar for individuals that used forest and coffee. However, condition and survival decreased in both habitats during the El Niño year. Apparent survival was also lower for individuals carrying a radiotag or geolocator. Our findings suggest that shade coffee with high canopy cover and height offers similar benefits to forest in terms of body condition and survival. Landscape conservation approaches, promoting diverse matrices of structurally complex shade coffee and forest might best ensure long-term survival in Neotropical migrants like Canada Warbler.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 12"},"PeriodicalIF":2.4,"publicationDate":"2020-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46599074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Multiple invasive cavity-nesting bird species can be present in a nest web, the network linking birds using cavities. We investigated the nest preferences and breeding phenologies of the cavity-nesting guild in the region surrounding Miami, Florida, USA, where invasive starlings, mynas, and parrots potentially usurp cavities from native woodpeckers and secondary cavity-nesters. We asked if the timing of reproduction determines which invasive species will usurp cavities from native birds with similar nest preferences. Nest usurpations between European Starlings (Sturnus vulgaris) and the woodpecker species present in Miami is well documented, but we predicted that a recently arrived sturnid species and introduced psittacids would also usurp nests. European Starlings had the largest breeding population of any species in our nest web, breeding during the peak of nesting season, and usurped the largest number of active nest cavities. We found that a small population of Common Mynas (Acridotheres tristis) usurped nests, sharing the peak-season nesting period with starlings and native woodpeckers. Parrots bred later than we expected, avoiding nest-site overlap with similarly large native birds that use cavities with similar characteristics. Parrots did not usurp any active nest cavities from native birds. Our results demonstrate how to use analysis of cavity characteristics and reproductive timing to evaluate threats to a cavity nest web posed by multiple invasive species. Common Myna currently usurp few nests; if they increase greatly in population, they could pose a problem for native cavity-nesters.
{"title":"Overlap in reproductive phenology increases the likelihood of cavity nest usurpation by invasive species in a tropical city","authors":"Joshua M. Diamond, M. Ross","doi":"10.1093/condor/duaa013","DOIUrl":"https://doi.org/10.1093/condor/duaa013","url":null,"abstract":"ABSTRACT Multiple invasive cavity-nesting bird species can be present in a nest web, the network linking birds using cavities. We investigated the nest preferences and breeding phenologies of the cavity-nesting guild in the region surrounding Miami, Florida, USA, where invasive starlings, mynas, and parrots potentially usurp cavities from native woodpeckers and secondary cavity-nesters. We asked if the timing of reproduction determines which invasive species will usurp cavities from native birds with similar nest preferences. Nest usurpations between European Starlings (Sturnus vulgaris) and the woodpecker species present in Miami is well documented, but we predicted that a recently arrived sturnid species and introduced psittacids would also usurp nests. European Starlings had the largest breeding population of any species in our nest web, breeding during the peak of nesting season, and usurped the largest number of active nest cavities. We found that a small population of Common Mynas (Acridotheres tristis) usurped nests, sharing the peak-season nesting period with starlings and native woodpeckers. Parrots bred later than we expected, avoiding nest-site overlap with similarly large native birds that use cavities with similar characteristics. Parrots did not usurp any active nest cavities from native birds. Our results demonstrate how to use analysis of cavity characteristics and reproductive timing to evaluate threats to a cavity nest web posed by multiple invasive species. Common Myna currently usurp few nests; if they increase greatly in population, they could pose a problem for native cavity-nesters.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 13"},"PeriodicalIF":2.4,"publicationDate":"2020-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45811851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conor C. Egan, B. F. Blackwell, E. Fernández‐Juricic, Page E. Klug
Wildlife managers have recently suggested the use of unmanned aircraft systems or drones as nonlethal hazing tools to deter birds from areas of human-wildlife conflict. However, it remains unclear if birds perceive common drone platforms as threatening. Based on field studies assessing behavioral and physiological responses, it is generally assumed that birds perceive less risk from drones than from predators. However, studies controlling for multiple confounding effects have not been conducted. Our goal was to establish the degree to which the perception of risk by birds would vary between common drone platforms relative to a predator model when flown at different approach types. We evaluated the behavioral responses of individual Red-winged Blackbirds (Agelaius phoeniceus) to 3 drone platforms: a predator model, a fixed-wing resembling an airplane, and a multirotor, approaching either head-on or overhead. Blackbirds became alert earlier (by 13.7 s), alarm-called more frequently (by a factor of 12), returned to forage later (by a factor of 4.7), and increased vigilance (by a factor of 1.3) in response to the predator model compared with the multirotor. Blackbirds also perceived the fixed-wing as riskier than the multirotor, but less risky than the predator model. Overhead approaches mostly failed to elicit flight in blackbirds across all platform types, and no blackbirds took flight in response to the multirotor at either overhead or head-on approaches. Our findings demonstrate that birds perceived drones with predatory characteristics as riskier than common drone models (i.e. fixed-wing and multirotor platforms). We recommend that drones be modified with additional stimuli to increase perceived risk when used as frightening devices, but avoided if used for wildlife monitoring.
{"title":"Testing a key assumption of using drones as frightening devices: Do birds perceive drones as risky?","authors":"Conor C. Egan, B. F. Blackwell, E. Fernández‐Juricic, Page E. Klug","doi":"10.1093/condor/duaa014","DOIUrl":"https://doi.org/10.1093/condor/duaa014","url":null,"abstract":"\u0000 Wildlife managers have recently suggested the use of unmanned aircraft systems or drones as nonlethal hazing tools to deter birds from areas of human-wildlife conflict. However, it remains unclear if birds perceive common drone platforms as threatening. Based on field studies assessing behavioral and physiological responses, it is generally assumed that birds perceive less risk from drones than from predators. However, studies controlling for multiple confounding effects have not been conducted. Our goal was to establish the degree to which the perception of risk by birds would vary between common drone platforms relative to a predator model when flown at different approach types. We evaluated the behavioral responses of individual Red-winged Blackbirds (Agelaius phoeniceus) to 3 drone platforms: a predator model, a fixed-wing resembling an airplane, and a multirotor, approaching either head-on or overhead. Blackbirds became alert earlier (by 13.7 s), alarm-called more frequently (by a factor of 12), returned to forage later (by a factor of 4.7), and increased vigilance (by a factor of 1.3) in response to the predator model compared with the multirotor. Blackbirds also perceived the fixed-wing as riskier than the multirotor, but less risky than the predator model. Overhead approaches mostly failed to elicit flight in blackbirds across all platform types, and no blackbirds took flight in response to the multirotor at either overhead or head-on approaches. Our findings demonstrate that birds perceived drones with predatory characteristics as riskier than common drone models (i.e. fixed-wing and multirotor platforms). We recommend that drones be modified with additional stimuli to increase perceived risk when used as frightening devices, but avoided if used for wildlife monitoring.","PeriodicalId":50624,"journal":{"name":"Condor","volume":"1 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2020-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44849749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cassandra G. Skaggs, Kevin M. Ringelman, C. Loesch, Michael L. Szymanski, F. Rohwer, K. Kemink
ABSTRACT Over the past decade, the United States has seen a rapid increase in oil and gas extraction from areas where resources were previously thought to be unrecoverable, particularly the Bakken shale formation in North Dakota. The Bakken overlaps with the Prairie Pothole Region, the most critical habitat in North America for breeding ducks, where oil and gas extraction through hydraulic fracturing has the potential to impact more than a million duck pairs in the United States alone. Here, we evaluated the effect of oil and gas development on nesting ducks in 2015–2017 across 5 counties in North Dakota. Using data from ∼4,000 nests we found that nest survival was higher at sites composed of a higher percentage of grassland, and for nests found closer to major roads. We found no effect of any metric of oil and gas extraction activity on duck nest survival. Using survival-corrected estimates of nest density, we found higher densities of nests closer to roads, but lower nest densities at sites surrounded by more wells. Our top-ranked model indicated that nest density was predicted to decline by 14% relative to sites with no development, given the average number of wells (3.15 wells) within 1,500 m of a site. However, within a nesting field, we found no evidence that ducks were avoiding petroleum-related infrastructure at smaller spatial scales. Our results indicate mixed effects of oil and gas development on nesting waterfowl, and highlight both the resiliency of dabbing ducks to environmental change and the need for additional research on other aspects of duck breeding biology.
{"title":"Proximity to oil wells in North Dakota does not impact nest success of ducks but lowers nest densities","authors":"Cassandra G. Skaggs, Kevin M. Ringelman, C. Loesch, Michael L. Szymanski, F. Rohwer, K. Kemink","doi":"10.1093/condor/duaa012","DOIUrl":"https://doi.org/10.1093/condor/duaa012","url":null,"abstract":"ABSTRACT Over the past decade, the United States has seen a rapid increase in oil and gas extraction from areas where resources were previously thought to be unrecoverable, particularly the Bakken shale formation in North Dakota. The Bakken overlaps with the Prairie Pothole Region, the most critical habitat in North America for breeding ducks, where oil and gas extraction through hydraulic fracturing has the potential to impact more than a million duck pairs in the United States alone. Here, we evaluated the effect of oil and gas development on nesting ducks in 2015–2017 across 5 counties in North Dakota. Using data from ∼4,000 nests we found that nest survival was higher at sites composed of a higher percentage of grassland, and for nests found closer to major roads. We found no effect of any metric of oil and gas extraction activity on duck nest survival. Using survival-corrected estimates of nest density, we found higher densities of nests closer to roads, but lower nest densities at sites surrounded by more wells. Our top-ranked model indicated that nest density was predicted to decline by 14% relative to sites with no development, given the average number of wells (3.15 wells) within 1,500 m of a site. However, within a nesting field, we found no evidence that ducks were avoiding petroleum-related infrastructure at smaller spatial scales. Our results indicate mixed effects of oil and gas development on nesting waterfowl, and highlight both the resiliency of dabbing ducks to environmental change and the need for additional research on other aspects of duck breeding biology.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 15"},"PeriodicalIF":2.4,"publicationDate":"2020-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49215027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Forest fragmentation is a leading driver of biodiversity loss, yet its effects on positive species interactions remain poorly known. We examined the effects of fragmentation on mixed-species bird flocks in the Western Andes of Colombia. Using 500-m transect surveys (n = 14 transects), we sampled flocks in 8 fragments (range: 10–173 ha) and an unfragmented reference site within the same altitudinal band (1,900–2,200 m.a.s.l.) and matrix type (cattle pasture). We evaluated the relative contributions of 9 predictor variables, including patch size, distance from edge, and selective aspects of vegetation structure on the composition, size, species richness, functional diversity, and phylogenetic diversity of flocks. We found effects of both patch size and vegetation structure on flock species richness, size, and functional diversity, but no support for edge effects. Generally, flock richness and size responded differently to fragmentation than did functional and phylogenetic diversity metrics. Both flock size and richness increased with patch size, but this variable had no effect on functional and phylogenetic diversity. Flock richness and size increased in high-canopy forests with greater foliage height diversity, whereas unlogged, old-growth primary forests with large-diameter trees had lower flock richness and size, but significantly greater functional diversity. Phylogenetic diversity was not affected by patch size, edge effects, or vegetation structure. We found differences in flock composition in response to fragmentation. Richness of Furnariidae in flocks increased with increasing distance from edge and foliage height diversity, whereas that of Thraupidae and boreal migrant species increased in early successional and forest edge flocks, respectively. All flock diversity metrics differed significantly seasonally, with smaller, less diverse flocks observed in January–March than in June–August. Flocking behavior persisted in 10-ha fragments, likely because Andean flocks are ″open membership” in nature, but there was extensive species turnover as forest edge and generalist species replaced forest-interior species in smaller fragments.
{"title":"Patch size and vegetation structure drive changes to mixed-species flock diversity and composition across a gradient of fragment sizes in the Western Andes of Colombia","authors":"H. H. Jones, S. Robinson","doi":"10.1093/condor/duaa006","DOIUrl":"https://doi.org/10.1093/condor/duaa006","url":null,"abstract":"ABSTRACT Forest fragmentation is a leading driver of biodiversity loss, yet its effects on positive species interactions remain poorly known. We examined the effects of fragmentation on mixed-species bird flocks in the Western Andes of Colombia. Using 500-m transect surveys (n = 14 transects), we sampled flocks in 8 fragments (range: 10–173 ha) and an unfragmented reference site within the same altitudinal band (1,900–2,200 m.a.s.l.) and matrix type (cattle pasture). We evaluated the relative contributions of 9 predictor variables, including patch size, distance from edge, and selective aspects of vegetation structure on the composition, size, species richness, functional diversity, and phylogenetic diversity of flocks. We found effects of both patch size and vegetation structure on flock species richness, size, and functional diversity, but no support for edge effects. Generally, flock richness and size responded differently to fragmentation than did functional and phylogenetic diversity metrics. Both flock size and richness increased with patch size, but this variable had no effect on functional and phylogenetic diversity. Flock richness and size increased in high-canopy forests with greater foliage height diversity, whereas unlogged, old-growth primary forests with large-diameter trees had lower flock richness and size, but significantly greater functional diversity. Phylogenetic diversity was not affected by patch size, edge effects, or vegetation structure. We found differences in flock composition in response to fragmentation. Richness of Furnariidae in flocks increased with increasing distance from edge and foliage height diversity, whereas that of Thraupidae and boreal migrant species increased in early successional and forest edge flocks, respectively. All flock diversity metrics differed significantly seasonally, with smaller, less diverse flocks observed in January–March than in June–August. Flocking behavior persisted in 10-ha fragments, likely because Andean flocks are ″open membership” in nature, but there was extensive species turnover as forest edge and generalist species replaced forest-interior species in smaller fragments.","PeriodicalId":50624,"journal":{"name":"Condor","volume":"122 1","pages":"1 - 26"},"PeriodicalIF":2.4,"publicationDate":"2020-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47957358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Studies examining impacts of land cover typically focus on abundance, distribution, and/or community richness, overlooking underlying demographic processes such as survival or reproduction. Here, we present findings from a unique dataset that allowed us to measure the relationship between land cover and reproductive output across the distribution of the Mourning Dove (Zenaida macroura). We used hunter-derived, Mourning Dove wing data across 1,271 counties in the United States from 2008 to 2014 to estimate spatially explicit age ratios (juveniles: adults), an index of local reproductive output. We also used raster imagery data to estimate relationships between reproductive output and land cover and crop cover. We found that low reproductive output occurs in regions where Mourning Dove declines have been steepest. Our findings reveal that impacts of land cover vary geographically, but even at a coarse resolution, small changes in the relative proportion of human-dominated landscapes can have a significant impact on the reproductive output of this generalist species. Maize and soybean systems correlate with up to a 57% reduction in Mourning Dove reproductive output in the eastern United States. In the western United States, developed areas correlate with a 41% increase in reproductive output. Across the United States, native habitats had neutral or negative relationships with age ratios. Our study contributes continental-scale evidence that Mourning Dove reproductive output is largely driven by human-dominated land cover including agricultural and residential areas. With Mourning Doves declining across the range, discerning more fine-scale land cover factors is critical for ensuring Mourning Dove populations persist into the future.
{"title":"Human-dominated land cover corresponds to spatial variation in Mourning Dove (Zenaida macroura) reproductive output across the United States","authors":"David J. Muñoz, David E. Miller","doi":"10.1093/condor/duaa003","DOIUrl":"https://doi.org/10.1093/condor/duaa003","url":null,"abstract":"ABSTRACT Studies examining impacts of land cover typically focus on abundance, distribution, and/or community richness, overlooking underlying demographic processes such as survival or reproduction. Here, we present findings from a unique dataset that allowed us to measure the relationship between land cover and reproductive output across the distribution of the Mourning Dove (Zenaida macroura). We used hunter-derived, Mourning Dove wing data across 1,271 counties in the United States from 2008 to 2014 to estimate spatially explicit age ratios (juveniles: adults), an index of local reproductive output. We also used raster imagery data to estimate relationships between reproductive output and land cover and crop cover. We found that low reproductive output occurs in regions where Mourning Dove declines have been steepest. Our findings reveal that impacts of land cover vary geographically, but even at a coarse resolution, small changes in the relative proportion of human-dominated landscapes can have a significant impact on the reproductive output of this generalist species. Maize and soybean systems correlate with up to a 57% reduction in Mourning Dove reproductive output in the eastern United States. In the western United States, developed areas correlate with a 41% increase in reproductive output. Across the United States, native habitats had neutral or negative relationships with age ratios. Our study contributes continental-scale evidence that Mourning Dove reproductive output is largely driven by human-dominated land cover including agricultural and residential areas. With Mourning Doves declining across the range, discerning more fine-scale land cover factors is critical for ensuring Mourning Dove populations persist into the future.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 11"},"PeriodicalIF":2.4,"publicationDate":"2020-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47463683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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