Potential Effects of Environmental Contaminants on Recovery of the Aplomado Falcon in South Texas

Mora, Miguel A.; Lee, M. C. are; Jenny, J. Peter; Schultz, T.W.; Sericano, José L.; Clum, Nancy J.

doi:10.2307/3802128

Cited by 16 publications

(6 citation statements)

References 23 publications

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“…Greater concentrations of inorganic elements have been reported for other regions in the Rio Grande. Mercury concentrations in eggs of aplomado falcons ( Falco femoralis ) from the Brownsville region were as high as 4.1 μg/g during 1996 [24]. Carcasses of passerine birds (including swallows) from the Big Bend region had mean Hg and Se levels up to 2.5 and 14.6 μg/g dry weight, respectively, during 1997 [21].…”

Section: Discussionmentioning

confidence: 99%

Biomarkers of exposure and effects of environmental contaminants on swallows nesting along the Rio Grande, Texas, USA

Mora

Musquiz

Bickham

et al. 2006

Enviro Toxic and Chemistry

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We collected adult cave swallows (Petrochelidon fulva) and cliff swallows (P. pyrrhonota) during the breeding seasons in 1999 and 2000 from eight locations along the Rio Grande from Brownsville to El Paso (unless otherwise specified, all locations are Texas, USA) and an out-of-basin reference location. Body mass, spleen mass, hepatosomatic index (HSI), gonadosomatic index (GSI), thyroxine (T4) in plasma, DNA damage measured as the half-peak coefficient of variation of DNA content (HPCV) in blood cells, as well as acetylcholinesterase and butyrylcholinesterase in brain were compared with concentrations of organochlorines, metals, and metalloids in carcasses to determine potential effects of contaminants on swallows during the breeding season. Concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) were significantly greater in swallows from El Paso than in those from most locations, except for Pharr and Llano Grande. All swallows from these three locations had p,p'-DDE concentrations of 3 microg/g wet weight or greater. Swallows from El Paso either had or shared the highest concentrations of p,p'-DDE, polychlorinated biphenyls, and 13 inorganic elements. Swallows from El Paso exhibited greater spleen mass and HPCV values as well as lower T4 values compared with those from other locations. Thyroxine was a potential biomarker of contaminant exposure in swallows of the Rio Grande, because it was negatively correlated with p,p'-DDE and Se. Spleen mass was positively correlated with selenium and HSI and negatively correlated with body mass, GSI, Mn, and Ni. Overall, the present study suggests that insectivorous birds living in areas of high agricultural and industrial activity along the Rio Grande bioaccumulate environmental contaminants. These contaminants, particularly p,p'-DDE, may be among multiple factors that impact endocrine and hematopoietic function in Rio Grande swallows.

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Section: Discussionmentioning

confidence: 99%

Biomarkers of exposure and effects of environmental contaminants on swallows nesting along the Rio Grande, Texas, USA

Mora

Musquiz

Bickham

et al. 2006

Enviro Toxic and Chemistry

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“…including 5 by raccoons, 12 by unknown ground predators (most were probably raccoons), 2 by great horned owls, 7 by unknown avian predators (suspects include great horned owls, Chihuahuan ravens, white-tailed hawks, and crested caracaras), 1 by fire ants (Solenopsis wagneri), and 9 by unknown predators. Mora et al (1997) assessed the possible impact of environmental contaminants upon the recovery of aplomado falcons in southern Texas by assaying 1) plasma from 8 free-ranging individuals, 2) addled eggs from 2 nests, and 3) tissues from representative prey, including mourning doves (Zenaida macroura), eastern meadowlarks (Sturnela magna), dragonflies (Odonata), and cicadas (Homoptera). Organochlorines, including DDE, were below detection limits in the plasma, and appeared at insignificant levels in the eggs (1.4-1.8 ppm wet weight) and prey samples (0.02-0.25 ppm).…”

Section: Productivitymentioning

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Progress in restoring the aplomado falcon to southern Texas

Jenny¹,

Heinrich²,

Montoya³

et al. 2004

Wildlife Society Bulletin

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The northern aplomado falcon (Falco femoralis septentrionalis) was once fairly common in the savannas of southern Texas and in other parts of the American Southwest but virtually disappeared by the 1950s north of the Mexican border. It was federally listed as endangered in 1986. The Peregrine Fund established a captive breeding program based on 25 nestlings obtained from eastern Mexico during 1977‐1988. Following a pilot release project in 1985‐1989, a full‐scale release effort in the southern Texas plain began in 1993 employing techniques similar to those we developed for the peregrine falcon (Falco peregrinus). We produced 923 fledgling aplomado falcons, of which 812 were released in Texas on both federal wildlife refuges and private property. We observed released falcons breeding in the wild for the first time in 1995, and by 2002, 37 pairs were known and at least 87 wild young had fledged over an 8‐year period. Predation by raccoons (Procyon lotor) was a frequent cause of nest failure, and the great horned owl (Bubo virginianus) was the principal source of death in fledglings at hack sites, a factor that may limit aplomado falcon recovery in some areas of its former range. Enrollment of more than 5,500 km2 of private land under federally mediated “Safe Harbor” agreements encouraged landowner goodwill and cooperation and provided essential access to private property by affording relief from potential liability associated with the Endangered Species Act.

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“…Elevated concentrations of metals, metalloids, and organochlorine pesticides have been documented in sediments and river-dependent organisms throughout the RGB (Gamble et al, 1988;Ong et al, 1991;U.S. Environmental Protection Agency (USEPA), 1992;TNRCC, 1994aTNRCC, ,b, 1997Davis et al, 1995;Carter and Anderholm, 1997;Mora, 1997;Mora et al, 1997;Van Metre et al, 1997;Mora and Wainwright, 1998;Levings et al, 1998;Schmitt et al, 1999b;Moring, 1999).…”

Section: Introductionmentioning

confidence: 99%

Environmental contaminants and biomarker responses in fish from the Rio Grande and its U.S. tributaries: Spatial and temporal trends

Schmitt

Hinck

Blazer³

et al. 2005

Science of The Total Environment

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Dethloff, Gail M.; Bartish, Timothy M.; Coyle, James J.; and Tillitt, Donald E., "Environmental contaminants and biomarker responses in fish from the Rio Grande and its U.S. tributaries: Spatial and temporal trends" (2005 AbstractWe collected, examined, and analyzed 368 fish of seven species from 10 sites on rivers of the Rio Grande Basin (RGB) during late 1997 and early 1998 to document temporal and geographic trends in the concentrations of accumulative contaminants and to assess contaminant effects on the fish. Sites were located on the mainstem of the Rio Grande and on the Arroyo Colorado and Pecos River in Texas (TX), New Mexico (NM), and Colorado. Common carp (Cyprinus carpio) and largemouth bass (Micropterus salmoides) were the targeted species. Fish were examined in the field for internal and external visible gross lesions, selected organs were weighed to compute ponderal and organosomatic indices, and samples of tissues and fluids were obtained and preserved for analysis of fish health and reproductive biomarkers. Whole fish from each station were composited by species and gender and analyzed for organochlorine chemical residues and elemental contaminants using instrumental methods, and for 2,3,7,8-tetrachloro dibenzo-p-dioxin-like activity (TCDD-EQ) using the H4IIE rat hepatoma cell bioassay. Overall, fish from lower RGB stations contained greater concentrations of organochlorine pesticide residues and appeared to be less healthy than those from sites in the central and upper parts of the basin, as indicated by a general gradient of residue concentrations and biomarker responses. A minimal number of altered biomarkers and few or no elevated contaminant concentrations were noted in fish from the upper RGB. The exception was elevated concentrations [up to 0.46 Ag/g wet-weight (ww)] of total mercury (Hg) in predatory species from the Rio Grande at Elephant Butte Reservoir, NM, a condition documented in previous studies. Arsenic (As) and selenium (Se) concentrations were greatest in fish from sites in the central RGB; Se concentrations in fish from the Pecos River at Red Bluff Lake, TX and from the Rio Grande at Langtry, TX and Amistad International Reservoir, TX exceeded published fish and wildlife toxicity thresholds. In the lower RGB, residues of This article is a U.S. government work, and is not subject to copyright in the United States.p,pV-DDT metabolites (V1.69 Ag/g ww), chlordane-related compounds (V0.21 Ag/g ww), dieldrin (V0.0.05 Ag/g ww), and toxaphene (V2.4 Ag/g ww) were detected in fish from most sites; maximum concentrations were in channel catfish (Ictalurus punctatus) from the Arroyo Colorado at Harlingen, TX. Concentrations of one or more residues exceeded toxicity thresholds for fish and wildlife in fish from this site and from the Rio Grande at Mission, TX and Brownsville, TX; however, concentrations were lower than those reported by previous studies. In addition, the proportional concentrations of p,pV-DDT at all sites were low, indicating weathered DDT rather than the influx of new ma...

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Potential Effects of Environmental Contaminants on Recovery of the Aplomado Falcon in South Texas

Cited by 16 publications

References 23 publications

Biomarkers of exposure and effects of environmental contaminants on swallows nesting along the Rio Grande, Texas, USA

Biomarkers of exposure and effects of environmental contaminants on swallows nesting along the Rio Grande, Texas, USA

Progress in restoring the aplomado falcon to southern Texas

Environmental contaminants and biomarker responses in fish from the Rio Grande and its U.S. tributaries: Spatial and temporal trends

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