The value of radio telemetry for waterfowl research depends on the availability of suitable metho... more The value of radio telemetry for waterfowl research depends on the availability of suitable methods of attaching transmitters. In previous studies, external transmitters attached to adult Mallards (Arias platyrhynchos) with sutures and glue did not stay on birds reliably. In an attempt to improve transmitter retention, a method of attachment was tested in which 4-g transmitters were attached mid-dorsally with sutures and with a stainless steel anchor-shaped wire inserted subcutaneously (anchor transmitters). Field tests indicated that all of 26 female Mallards and 63 of 65 female Gadwalls (Arias strepera) retained their anchor transmitters during 4369 bird-days of monitoring during nesting and brood rearing. Survival rates of females with anchor transmitters compared favorably with those reported from other studies. In this study, females with and without anchor transmitters did not differ with respect to survival rates of their ducklings. The anchor transmitter may be suitable for a variety of field studies on numerous species.
Proximate analyses of carcasses of sandhill cranes (Grus canadensis) collected in the Central Pla... more Proximate analyses of carcasses of sandhill cranes (Grus canadensis) collected in the Central Platte River Valley (CPRV), Nebraska, during spring 1999 indicated a marked decline in fat levels from springs 1978 and 1979. Concern that amounts of fat cranes stored by their spring departures from the CPRV may have further declined prompted this evaluation. For our assessment, we made use of morphological measurements (culmen post nares, tarsus, flattened wing chord) along with body mass on each of 810 sandhill cranes that were collected for proximate analysis or captured with rocket nets at widely distributed sites in the CPRV during 1978-1979 and 1998-2005. For these birds, we conducted a principal components analysis to develop a body size variable when testing the relationship between mass and date. We next evaluated whether masses at arrival and departure and rates of mass gain in sandhill cranes differed from previous (1978 and 1979) and current (1998-2005) studies and addressed the implications of our findings.
Number and geographic distribution of greater sandhill cranes (Grus canadensis tabida) in the mid... more Number and geographic distribution of greater sandhill cranes (Grus canadensis tabida) in the mid-continent population (MCP) of sandhill cranes were evaluated. G. c. tabida comprised 7 of 133 (5.3%) individuals of 3 subspecies which projects to 31,579 ± 11,661 (SE) individuals in an estimated spring MCP of 600,000 cranes. From a platform transmitting terminal (PTT)-marked sample representative of the geographic distribution of G. c. tabida, 10 of 13 (77%) settled during the breeding season in east-central Canada/Minnesota, including 4 in northwestern Minnesota, 4 in Manitoba (2 at sites near the Minnesota border), and 2 in Ontario. Three (23%) cranes settled in west-central Canada (1 in Saskatchewan and 2 in Alberta). From a sample of 16 VHF-radioed G. c. tabida representative of MCP distribution during 2003-2006, 11 (69%) and 5 (31%) originated from breeding grounds in east-central Canada and west-central Canada, respectively. Eight of 13 (62%) PTTmarked G. c. tabida settled in transition areas between the temperate prairies, and the mixed woods shield and the boreal plain ecological regions during the breeding season. Breeding distributions of PTT-marked G. c. tabida overlapped with G. c. rowani extensively in east-central Canada and Minnesota. All PTT-marked G. c. tabida that settled on breeding grounds in Canada staged in areas open to sport hunting in Saskatchewan, Manitoba, and North Dakota during fall; mean arrival and departure dates from staging areas were 7 September and 19 October (n = 12), for an average stay of 40 ± 4 (SE) days. G. c. tabida that spent the breeding season in Minnesota stayed in Minnesota during fall and experienced less exposure to hunting seasons over the fall/winter period than cranes breeding in Canada (26%, n = 3, vs. 55%, n = 8). A reduction in G. c. tabida harvest likely would be required for sandhill cranes to move beyond their current status as an occasional breeder across most of the northern plains, including the Prairie Pothole Region.
Little information exists on the spring migratory habits and breeding distribution of lesser sand... more Little information exists on the spring migratory habits and breeding distribution of lesser sandhill cranes (Grus canadensis canadensis) that winter in west-central New Mexico and southeastern Arizona. To address this question, we captured and attached a total of 6 Platform Transmitting Terminals (PTT) to adult lesser sandhill cranes at 2 sites each in west-central New Mexico and southeastern Arizona during December 2001 and monitored the birds' movements to arrival on their arctic breeding grounds. After departing from their wintering grounds, 2 of the cranes stopped at Monte Vista NWR in south-central Colorado where they stayed for 17 and 23 days. All 6 cranes migrated to Nebraska, where 5 stopped in the North Platte River Valley (2 near Lewellen and 3 near Hershey) and 1 in the Central Platte River Valley near Kearney (mean length of stay = 24.5 days, range 8.5-33). The migration pathways taken to Nebraska by the 6 cranes were, on average, 1,192 km farther than direct flight distances from wintering to breeding grounds. Four cranes were present on the surveyed sites in Nebraska on 26 March, when the U.S. Fish and Wildlife Service conducted their 2002 crane population census; the 2 cranes that stopped at the Monte Vista National Wildlife Refuge did not arrive in Nebraska until about 4 April. From Nebraska, all 6 cranes migrated to western Saskatchewan; 3 later moved to sites in eastern Alberta (mean length of stay in Saskatchewan/Alberta = 21 days, range 12.7-28.0). From Saskatchewan and Alberta, the cranes flew, with a few brief intervening stops, to breeding grounds located on the Yukon-Kuskokwim Delta in western Alaska (n = 2) and the Chukotka Penninsula, Chaun Delta, and Anadyr Delta in northeastern Siberia (n = 4). Use of the Central Platte or North Platte River valleys by all 6 cranes was unexpected given the major increase in flight distance required and reflects the exceptional attachment to Nebraska staging areas by the mid-continent population of sandhill cranes. Spring migration routes, staging locations, and breeding distributions of these 6 cranes suggest that lesser sandhill cranes wintering in west-central New Mexico and in southeastern Arizona are affiliated with the Western Alaska/Siberia subpopulation.
The U.S. Fish and Wildlife Service relies on an annual aerial photo-corrected survey conducted on... more The U.S. Fish and Wildlife Service relies on an annual aerial photo-corrected survey conducted on the fourth Tuesday of March each year in the Central Platte River Valley (CPRV) and North Platte River Valley (NPRV) of Nebraska to estimate size of the midcontinental population (MCP) of sandhill cranes (Grus canadensis) to help guide population management. Wide unaccounted for annual fluctuations in survey counts over the past 25 years have raised concerns that many cranes either have left the Platte before the survey, have not yet arrived, or over fly the Platte entirely in some years. As a result, crane managers in the Division of Migratory Bird Management of the u.S. Fish and Wildlife Service and states in the Central Flyway requested that we evaluate temporal patterns of use of the CPRV in spring, and estimate percentage of MCP cranes present on the survey date each year, and assess whether part of the population uses the CPRV and NPRV intermittently. To evaluate length and pattern of stay, we monitored a representative sample of radio-marked sandhill cranes (n = 179) from their arrival to departure from the CPRV in year(s) following capture and estimated percentages of the population present on each survey date over a 5-year period (2001-2005). To evaluate whether part of the population over flies the CPRV and NPRV in some years we monitored a representative sample of PTT-marked sandhill cranes (n = 70) on their spring migration from the wintering to breeding grounds in the year following their capture and marking (1998-2002). Results of the study will provide crane managers with improved insight into the temporal dynamics of use of the CPRV and NPRV by the MCP and help establish how reliably the annual March survey tracks population change.
Number and geographic distribution of greater sandhill cranes (Grus canadensis tabida) in the mid... more Number and geographic distribution of greater sandhill cranes (Grus canadensis tabida) in the mid-continent population (MCP) of sandhill cranes were evaluated. G. c. tabida comprised 7 of 133 (5.3%) individuals of 3 subspecies which projects to 31,579 ± 11,661 (SE) individuals in an estimated spring MCP of 600,000 cranes. From a platform transmitting terminal (PTT)-marked sample representative of the geographic distribution of G. c. tabida, 10 of 13 (77%) settled during the breeding season in east-central Canada/Minnesota, including 4 in northwestern Minnesota, 4 in Manitoba (2 at sites near the Minnesota border), and 2 in Ontario. Three (23%) cranes settled in west-central Canada (1 in Saskatchewan and 2 in Alberta). From a sample of 16 VHF-radioed G. c. tabida representative of MCP distribution during 2003-2006, 11 (69%) and 5 (31%) originated from breeding grounds in east-central Canada and west-central Canada, respectively. Eight of 13 (62%) PTTmarked G. c. tabida settled in transition areas between the temperate prairies, and the mixed woods shield and the boreal plain ecological regions during the breeding season. Breeding distributions of PTT-marked G. c. tabida overlapped with G. c. rowani extensively in east-central Canada and Minnesota. All PTT-marked G. c. tabida that settled on breeding grounds in Canada staged in areas open to sport hunting in Saskatchewan, Manitoba, and North Dakota during fall; mean arrival and departure dates from staging areas were 7 September and 19 October (n = 12), for an average stay of 40 ± 4 (SE) days. G. c. tabida that spent the breeding season in Minnesota stayed in Minnesota during fall and experienced less exposure to hunting seasons over the fall/winter period than cranes breeding in Canada (26%, n = 3, vs. 55%, n = 8). A reduction in G. c. tabida harvest likely would be required for sandhill cranes to move beyond their current status as an occasional breeder across most of the northern plains, including the Prairie Pothole Region.
We used radiotelemetry to study mallard (Anas platyrhynchos) brood movements, wetland use, and du... more We used radiotelemetry to study mallard (Anas platyrhynchos) brood movements, wetland use, and duckling survival during a major drought (1988-1992) and during the first 2 years of the subsequent wet period (1993-1994) at 4 51-km 2 sites in prairie pothole landscapes in eastern North Dakota, USA. About two-thirds of 69 radiomarked mallard broods initiated moves from the nest to water before noon, and all left the nest during daylight. On average, broods used fewer wetlands, but moved greater distances during the dry period than the wet period. Broods of all ages were more likely to make inter-wetland moves during the wet period and probabilities of inter-wetland moves decreased as duckling age increased, especially during the dry period. Brood use of seasonal wetlands nearly doubled from 22% to 43% and use of semi-permanent wetlands declined from 73% to 50% from the dry to the wet period. Eighty-one of 150 radiomarked ducklings died during 1,604 exposure days. We evaluated survival models containing variables related to water conditions, weather, duckling age, and hatch date. Model-averaged risk ratios indicated that, on any given date, radiomarked ducklings were 1.5 (95% CI ¼ 0.8-2.8) times more likely to die when the percentage of seasonal basins containing water (WETSEAS) was 18% than when WETSEAS was .40%. An interaction between duckling age and occurrence of rain on the current or 2 previous days indicated that rain effects were pronounced when ducklings were 0-7 days old but negligible when they were 8-30 days old. The TMIN (mean daily minimum temperature on the current and 2 previous days) effects generally were consistent between duckling age classes, and the risk of duckling death increased 9.3% for each 18C decrease in TMIN across both age classes. Overall, the 30-day survival rate of ducklings equipped with radiotransmitters was about 0.23 lower than the survival rate of those without radiotransmitters. Unmarked ducklings were 7.6 (95% CI ¼ 2.7-21.3) times more likely to die on any given day when WETSEAS was 18% than when WETSEAS was .40%. Higher duckling survival and increased use of seasonal wetlands during the wet period suggest that mallard production will benefit from programs that conserve and restore seasonal wetland habitat. Given adverse effects of low temperatures on duckling survival, managers may want to include this stochastic variable in models used to predict annual production of mallards in the
Numbers of arctic-nesting geese staging in spring in the Central Platte River Valley (CPRV) of so... more Numbers of arctic-nesting geese staging in spring in the Central Platte River Valley (CPRV) of southcentral Nebraska increased dramatically from the 1970s to the 1990s, raising concerns that geese may be competing with the mid-continental population of sandhill cranes (Grus canadensis) for waste corn. From late February to mid-April 1998-2001, we measured temporal patterns of cropland use, evaluated habitat preferences, and compared numbers of geese using the primary crane-occupied parts of the CPRV area with numbers of sandhill cranes. Numbers of Canada geese (Branta canadensis), lesser snow geese (Chen caerulescens)/Ross' geese (Chen rossii), and greater white-fronted geese (Anser albifrons) peaked an average of 2.3, 2.8, and 1.5 weeks before sandhill cranes, with 90% of goose numbers occurring by 21, 15, and 21 March when averaged over the 4-year period. Numbers of sandhill cranes, on average, were highest on 26 March. All bird groups used corn habitats in greater proportion than expected based on their availability (land area) and used soybean habitats less than expected. Across years, 37.5, 82.5, 53.7, and 44.3% of Canada geese, lesser snow geese/Ross' geese, greater white-fronted geese, and sandhill cranes, respectively, occurred in quadrants in which cornfields in various post-harvest treatments constituted > 90% of the annually planted cropland. From 1998 through 2001, 0.1, 0, 0, and 2.5% of Canada geese, lesser snow geese/Ross' geese, greater white-fronted geese, and sandhill cranes, respectively, occurred in quadrants where > 90% of the annually planted cropland was in soybeans. Overall, estimated numbers of geese annually averaged 66, 46, 39, and 62% of estimated numbers of cranes in the CPRV. When viewed in the context that arcticnesting geese rely primarily on waste corn to meet their energy needs in Nebraska and crane capacity to store fat has declined over the past 20 years, these relationships suggest geese were important competitors of sandhill cranes for waste corn in the CPRV area during 1998-2001.
The Central Platte River Valley (CPRV) in Nebraska is a key spring staging area for approximately... more The Central Platte River Valley (CPRV) in Nebraska is a key spring staging area for approximately 80% of the midcontinent population of sandhill cranes (Grus canadensis). Evidence that cranes currently are acquiring fat less efficiently than in the past along with a large increase in use of the CPRV by snow geese (Chen caerulescens) led us to evaluate waste-corn availability and index spatial and temporal variation in abundance of sandhill cranes and waterfowl using the CPRV. We also developed a predictive model to assess impact of changes in availability of corn under past, present, and potential future conditions.
were integral to the initiation and continuation of this work. We thank B. Hartup, M. Folk, S. He... more were integral to the initiation and continuation of this work. We thank B. Hartup, M. Folk, S. Herford, W. Wehtje, and J. Dooley for assistance and support during crane capture or other aspects. J. Fieberg and E. Vander Wal provided comments to earlier versions of this report.
We used radiotelemetry to study mallard (Anas platyrhynchos) brood movements, wetland use, and du... more We used radiotelemetry to study mallard (Anas platyrhynchos) brood movements, wetland use, and duckling survival during a major drought (1988)(1989)(1990)(1991)(1992) and during the first 2 years of the subsequent wet period (1993)(1994) at 4 51-km 2 sites in prairie pothole landscapes in eastern North Dakota, USA. About two-thirds of 69 radiomarked mallard broods initiated moves from the nest to water before noon, and all left the nest during daylight. On average, broods used fewer wetlands, but moved greater distances during the dry period than the wet period. Broods of all ages were more likely to make inter-wetland moves during the wet period and probabilities of inter-wetland moves decreased as duckling age increased, especially during the dry period. Brood use of seasonal wetlands nearly doubled from 22% to 43% and use of semi-permanent wetlands declined from 73% to 50% from the dry to the wet period. Eighty-one of 150 radiomarked ducklings died during 1,604 exposure days. We evaluated survival models containing variables related to water conditions, weather, duckling age, and hatch date. Model-averaged risk ratios indicated that, on any given date, radiomarked ducklings were 1.5 (95% CI ¼ 0.8-2.8) times more likely to die when the percentage of seasonal basins containing water (WETSEAS) was 18% than when WETSEAS was .40%. An interaction between duckling age and occurrence of rain on the current or 2 previous days indicated that rain effects were pronounced when ducklings were 0-7 days old but negligible when they were 8-30 days old. The TMIN (mean daily minimum temperature on the current and 2 previous days) effects generally were consistent between duckling age classes, and the risk of duckling death increased 9.3% for each 18C decrease in TMIN across both age classes. Overall, the 30-day survival rate of ducklings equipped with radiotransmitters was about 0.23 lower than the survival rate of those without radiotransmitters. Unmarked ducklings were 7.6 (95% CI ¼ 2.7-21.3) times more likely to die on any given day when WETSEAS was 18% than when WETSEAS was .40%. Higher duckling survival and increased use of seasonal wetlands during the wet period suggest that mallard production will benefit from programs that conserve and restore seasonal wetland habitat. Given adverse effects of low temperatures on duckling survival, managers may want to include this stochastic variable in models used to predict annual production of mallards in the Prairie
Siliceous sponges can synthesize poly(silicate) for their spicules enzymatically using silicatein... more Siliceous sponges can synthesize poly(silicate) for their spicules enzymatically using silicatein. We found that silicatein exists in silica-filled cell organelles (silicasomes) that transport the enzyme to the spicules. We show for the first time that recombinant silicatein acts as a silica polymerase and also as a silica esterase. The enzymatic polymerization/polycondensation of silicic acid follows a distinct course. In addition, we show that silicatein cleaves the ester-like bond in bis(p-aminophenoxy)-dimethylsilane. Enzymatic parameters for silica esterase activity are given. The reaction is completely blocked by sodium hexafluorosilicate and E-64. We consider that the dual function of silicatein (silica polymerase and silica esterase) will be useful for the rational synthesis of structured new silica biomaterials.
Progress in molecular and subcellular biology, 2009
Silica-based materials are used in many high-tech products including microelectronics, optoelectr... more Silica-based materials are used in many high-tech products including microelectronics, optoelectronics, and catalysts. Siliceous sponges (Demospongiae and Hexactinellida) are unique in their ability to synthesize silica enzymatically. We have cloned the silica-forming enzymes, silicateins, from both demosponges (marine and freshwater sponges) and hexactinellid sponges. The recombinant enzymes allow the synthesis of silica under environmentally benign ambient conditions, while the technical (chemical) production of silica commonly requires high temperatures and pressures, and extremes of pH. Silicateins can be used for the fabrication of highly-ordered inorganic-organic composite materials with defined optical, electrical, and mechanical properties. The simple self-assembly properties of silicateins which are able to form silica and other metal oxides in aqueous solution allow the development of novel products in nano(bio)technology, medicine, and dentistry.
The value of radio telemetry for waterfowl research depends on the availability of suitable metho... more The value of radio telemetry for waterfowl research depends on the availability of suitable methods of attaching transmitters. In previous studies, external transmitters attached to adult Mallards (Arias platyrhynchos) with sutures and glue did not stay on birds reliably. In an attempt to improve transmitter retention, a method of attachment was tested in which 4-g transmitters were attached mid-dorsally with sutures and with a stainless steel anchor-shaped wire inserted subcutaneously (anchor transmitters). Field tests indicated that all of 26 female Mallards and 63 of 65 female Gadwalls (Arias strepera) retained their anchor transmitters during 4369 bird-days of monitoring during nesting and brood rearing. Survival rates of females with anchor transmitters compared favorably with those reported from other studies. In this study, females with and without anchor transmitters did not differ with respect to survival rates of their ducklings. The anchor transmitter may be suitable for a variety of field studies on numerous species.
Proximate analyses of carcasses of sandhill cranes (Grus canadensis) collected in the Central Pla... more Proximate analyses of carcasses of sandhill cranes (Grus canadensis) collected in the Central Platte River Valley (CPRV), Nebraska, during spring 1999 indicated a marked decline in fat levels from springs 1978 and 1979. Concern that amounts of fat cranes stored by their spring departures from the CPRV may have further declined prompted this evaluation. For our assessment, we made use of morphological measurements (culmen post nares, tarsus, flattened wing chord) along with body mass on each of 810 sandhill cranes that were collected for proximate analysis or captured with rocket nets at widely distributed sites in the CPRV during 1978-1979 and 1998-2005. For these birds, we conducted a principal components analysis to develop a body size variable when testing the relationship between mass and date. We next evaluated whether masses at arrival and departure and rates of mass gain in sandhill cranes differed from previous (1978 and 1979) and current (1998-2005) studies and addressed the implications of our findings.
Number and geographic distribution of greater sandhill cranes (Grus canadensis tabida) in the mid... more Number and geographic distribution of greater sandhill cranes (Grus canadensis tabida) in the mid-continent population (MCP) of sandhill cranes were evaluated. G. c. tabida comprised 7 of 133 (5.3%) individuals of 3 subspecies which projects to 31,579 ± 11,661 (SE) individuals in an estimated spring MCP of 600,000 cranes. From a platform transmitting terminal (PTT)-marked sample representative of the geographic distribution of G. c. tabida, 10 of 13 (77%) settled during the breeding season in east-central Canada/Minnesota, including 4 in northwestern Minnesota, 4 in Manitoba (2 at sites near the Minnesota border), and 2 in Ontario. Three (23%) cranes settled in west-central Canada (1 in Saskatchewan and 2 in Alberta). From a sample of 16 VHF-radioed G. c. tabida representative of MCP distribution during 2003-2006, 11 (69%) and 5 (31%) originated from breeding grounds in east-central Canada and west-central Canada, respectively. Eight of 13 (62%) PTTmarked G. c. tabida settled in transition areas between the temperate prairies, and the mixed woods shield and the boreal plain ecological regions during the breeding season. Breeding distributions of PTT-marked G. c. tabida overlapped with G. c. rowani extensively in east-central Canada and Minnesota. All PTT-marked G. c. tabida that settled on breeding grounds in Canada staged in areas open to sport hunting in Saskatchewan, Manitoba, and North Dakota during fall; mean arrival and departure dates from staging areas were 7 September and 19 October (n = 12), for an average stay of 40 ± 4 (SE) days. G. c. tabida that spent the breeding season in Minnesota stayed in Minnesota during fall and experienced less exposure to hunting seasons over the fall/winter period than cranes breeding in Canada (26%, n = 3, vs. 55%, n = 8). A reduction in G. c. tabida harvest likely would be required for sandhill cranes to move beyond their current status as an occasional breeder across most of the northern plains, including the Prairie Pothole Region.
Little information exists on the spring migratory habits and breeding distribution of lesser sand... more Little information exists on the spring migratory habits and breeding distribution of lesser sandhill cranes (Grus canadensis canadensis) that winter in west-central New Mexico and southeastern Arizona. To address this question, we captured and attached a total of 6 Platform Transmitting Terminals (PTT) to adult lesser sandhill cranes at 2 sites each in west-central New Mexico and southeastern Arizona during December 2001 and monitored the birds' movements to arrival on their arctic breeding grounds. After departing from their wintering grounds, 2 of the cranes stopped at Monte Vista NWR in south-central Colorado where they stayed for 17 and 23 days. All 6 cranes migrated to Nebraska, where 5 stopped in the North Platte River Valley (2 near Lewellen and 3 near Hershey) and 1 in the Central Platte River Valley near Kearney (mean length of stay = 24.5 days, range 8.5-33). The migration pathways taken to Nebraska by the 6 cranes were, on average, 1,192 km farther than direct flight distances from wintering to breeding grounds. Four cranes were present on the surveyed sites in Nebraska on 26 March, when the U.S. Fish and Wildlife Service conducted their 2002 crane population census; the 2 cranes that stopped at the Monte Vista National Wildlife Refuge did not arrive in Nebraska until about 4 April. From Nebraska, all 6 cranes migrated to western Saskatchewan; 3 later moved to sites in eastern Alberta (mean length of stay in Saskatchewan/Alberta = 21 days, range 12.7-28.0). From Saskatchewan and Alberta, the cranes flew, with a few brief intervening stops, to breeding grounds located on the Yukon-Kuskokwim Delta in western Alaska (n = 2) and the Chukotka Penninsula, Chaun Delta, and Anadyr Delta in northeastern Siberia (n = 4). Use of the Central Platte or North Platte River valleys by all 6 cranes was unexpected given the major increase in flight distance required and reflects the exceptional attachment to Nebraska staging areas by the mid-continent population of sandhill cranes. Spring migration routes, staging locations, and breeding distributions of these 6 cranes suggest that lesser sandhill cranes wintering in west-central New Mexico and in southeastern Arizona are affiliated with the Western Alaska/Siberia subpopulation.
The U.S. Fish and Wildlife Service relies on an annual aerial photo-corrected survey conducted on... more The U.S. Fish and Wildlife Service relies on an annual aerial photo-corrected survey conducted on the fourth Tuesday of March each year in the Central Platte River Valley (CPRV) and North Platte River Valley (NPRV) of Nebraska to estimate size of the midcontinental population (MCP) of sandhill cranes (Grus canadensis) to help guide population management. Wide unaccounted for annual fluctuations in survey counts over the past 25 years have raised concerns that many cranes either have left the Platte before the survey, have not yet arrived, or over fly the Platte entirely in some years. As a result, crane managers in the Division of Migratory Bird Management of the u.S. Fish and Wildlife Service and states in the Central Flyway requested that we evaluate temporal patterns of use of the CPRV in spring, and estimate percentage of MCP cranes present on the survey date each year, and assess whether part of the population uses the CPRV and NPRV intermittently. To evaluate length and pattern of stay, we monitored a representative sample of radio-marked sandhill cranes (n = 179) from their arrival to departure from the CPRV in year(s) following capture and estimated percentages of the population present on each survey date over a 5-year period (2001-2005). To evaluate whether part of the population over flies the CPRV and NPRV in some years we monitored a representative sample of PTT-marked sandhill cranes (n = 70) on their spring migration from the wintering to breeding grounds in the year following their capture and marking (1998-2002). Results of the study will provide crane managers with improved insight into the temporal dynamics of use of the CPRV and NPRV by the MCP and help establish how reliably the annual March survey tracks population change.
Number and geographic distribution of greater sandhill cranes (Grus canadensis tabida) in the mid... more Number and geographic distribution of greater sandhill cranes (Grus canadensis tabida) in the mid-continent population (MCP) of sandhill cranes were evaluated. G. c. tabida comprised 7 of 133 (5.3%) individuals of 3 subspecies which projects to 31,579 ± 11,661 (SE) individuals in an estimated spring MCP of 600,000 cranes. From a platform transmitting terminal (PTT)-marked sample representative of the geographic distribution of G. c. tabida, 10 of 13 (77%) settled during the breeding season in east-central Canada/Minnesota, including 4 in northwestern Minnesota, 4 in Manitoba (2 at sites near the Minnesota border), and 2 in Ontario. Three (23%) cranes settled in west-central Canada (1 in Saskatchewan and 2 in Alberta). From a sample of 16 VHF-radioed G. c. tabida representative of MCP distribution during 2003-2006, 11 (69%) and 5 (31%) originated from breeding grounds in east-central Canada and west-central Canada, respectively. Eight of 13 (62%) PTTmarked G. c. tabida settled in transition areas between the temperate prairies, and the mixed woods shield and the boreal plain ecological regions during the breeding season. Breeding distributions of PTT-marked G. c. tabida overlapped with G. c. rowani extensively in east-central Canada and Minnesota. All PTT-marked G. c. tabida that settled on breeding grounds in Canada staged in areas open to sport hunting in Saskatchewan, Manitoba, and North Dakota during fall; mean arrival and departure dates from staging areas were 7 September and 19 October (n = 12), for an average stay of 40 ± 4 (SE) days. G. c. tabida that spent the breeding season in Minnesota stayed in Minnesota during fall and experienced less exposure to hunting seasons over the fall/winter period than cranes breeding in Canada (26%, n = 3, vs. 55%, n = 8). A reduction in G. c. tabida harvest likely would be required for sandhill cranes to move beyond their current status as an occasional breeder across most of the northern plains, including the Prairie Pothole Region.
We used radiotelemetry to study mallard (Anas platyrhynchos) brood movements, wetland use, and du... more We used radiotelemetry to study mallard (Anas platyrhynchos) brood movements, wetland use, and duckling survival during a major drought (1988-1992) and during the first 2 years of the subsequent wet period (1993-1994) at 4 51-km 2 sites in prairie pothole landscapes in eastern North Dakota, USA. About two-thirds of 69 radiomarked mallard broods initiated moves from the nest to water before noon, and all left the nest during daylight. On average, broods used fewer wetlands, but moved greater distances during the dry period than the wet period. Broods of all ages were more likely to make inter-wetland moves during the wet period and probabilities of inter-wetland moves decreased as duckling age increased, especially during the dry period. Brood use of seasonal wetlands nearly doubled from 22% to 43% and use of semi-permanent wetlands declined from 73% to 50% from the dry to the wet period. Eighty-one of 150 radiomarked ducklings died during 1,604 exposure days. We evaluated survival models containing variables related to water conditions, weather, duckling age, and hatch date. Model-averaged risk ratios indicated that, on any given date, radiomarked ducklings were 1.5 (95% CI ¼ 0.8-2.8) times more likely to die when the percentage of seasonal basins containing water (WETSEAS) was 18% than when WETSEAS was .40%. An interaction between duckling age and occurrence of rain on the current or 2 previous days indicated that rain effects were pronounced when ducklings were 0-7 days old but negligible when they were 8-30 days old. The TMIN (mean daily minimum temperature on the current and 2 previous days) effects generally were consistent between duckling age classes, and the risk of duckling death increased 9.3% for each 18C decrease in TMIN across both age classes. Overall, the 30-day survival rate of ducklings equipped with radiotransmitters was about 0.23 lower than the survival rate of those without radiotransmitters. Unmarked ducklings were 7.6 (95% CI ¼ 2.7-21.3) times more likely to die on any given day when WETSEAS was 18% than when WETSEAS was .40%. Higher duckling survival and increased use of seasonal wetlands during the wet period suggest that mallard production will benefit from programs that conserve and restore seasonal wetland habitat. Given adverse effects of low temperatures on duckling survival, managers may want to include this stochastic variable in models used to predict annual production of mallards in the
Numbers of arctic-nesting geese staging in spring in the Central Platte River Valley (CPRV) of so... more Numbers of arctic-nesting geese staging in spring in the Central Platte River Valley (CPRV) of southcentral Nebraska increased dramatically from the 1970s to the 1990s, raising concerns that geese may be competing with the mid-continental population of sandhill cranes (Grus canadensis) for waste corn. From late February to mid-April 1998-2001, we measured temporal patterns of cropland use, evaluated habitat preferences, and compared numbers of geese using the primary crane-occupied parts of the CPRV area with numbers of sandhill cranes. Numbers of Canada geese (Branta canadensis), lesser snow geese (Chen caerulescens)/Ross' geese (Chen rossii), and greater white-fronted geese (Anser albifrons) peaked an average of 2.3, 2.8, and 1.5 weeks before sandhill cranes, with 90% of goose numbers occurring by 21, 15, and 21 March when averaged over the 4-year period. Numbers of sandhill cranes, on average, were highest on 26 March. All bird groups used corn habitats in greater proportion than expected based on their availability (land area) and used soybean habitats less than expected. Across years, 37.5, 82.5, 53.7, and 44.3% of Canada geese, lesser snow geese/Ross' geese, greater white-fronted geese, and sandhill cranes, respectively, occurred in quadrants in which cornfields in various post-harvest treatments constituted > 90% of the annually planted cropland. From 1998 through 2001, 0.1, 0, 0, and 2.5% of Canada geese, lesser snow geese/Ross' geese, greater white-fronted geese, and sandhill cranes, respectively, occurred in quadrants where > 90% of the annually planted cropland was in soybeans. Overall, estimated numbers of geese annually averaged 66, 46, 39, and 62% of estimated numbers of cranes in the CPRV. When viewed in the context that arcticnesting geese rely primarily on waste corn to meet their energy needs in Nebraska and crane capacity to store fat has declined over the past 20 years, these relationships suggest geese were important competitors of sandhill cranes for waste corn in the CPRV area during 1998-2001.
The Central Platte River Valley (CPRV) in Nebraska is a key spring staging area for approximately... more The Central Platte River Valley (CPRV) in Nebraska is a key spring staging area for approximately 80% of the midcontinent population of sandhill cranes (Grus canadensis). Evidence that cranes currently are acquiring fat less efficiently than in the past along with a large increase in use of the CPRV by snow geese (Chen caerulescens) led us to evaluate waste-corn availability and index spatial and temporal variation in abundance of sandhill cranes and waterfowl using the CPRV. We also developed a predictive model to assess impact of changes in availability of corn under past, present, and potential future conditions.
were integral to the initiation and continuation of this work. We thank B. Hartup, M. Folk, S. He... more were integral to the initiation and continuation of this work. We thank B. Hartup, M. Folk, S. Herford, W. Wehtje, and J. Dooley for assistance and support during crane capture or other aspects. J. Fieberg and E. Vander Wal provided comments to earlier versions of this report.
We used radiotelemetry to study mallard (Anas platyrhynchos) brood movements, wetland use, and du... more We used radiotelemetry to study mallard (Anas platyrhynchos) brood movements, wetland use, and duckling survival during a major drought (1988)(1989)(1990)(1991)(1992) and during the first 2 years of the subsequent wet period (1993)(1994) at 4 51-km 2 sites in prairie pothole landscapes in eastern North Dakota, USA. About two-thirds of 69 radiomarked mallard broods initiated moves from the nest to water before noon, and all left the nest during daylight. On average, broods used fewer wetlands, but moved greater distances during the dry period than the wet period. Broods of all ages were more likely to make inter-wetland moves during the wet period and probabilities of inter-wetland moves decreased as duckling age increased, especially during the dry period. Brood use of seasonal wetlands nearly doubled from 22% to 43% and use of semi-permanent wetlands declined from 73% to 50% from the dry to the wet period. Eighty-one of 150 radiomarked ducklings died during 1,604 exposure days. We evaluated survival models containing variables related to water conditions, weather, duckling age, and hatch date. Model-averaged risk ratios indicated that, on any given date, radiomarked ducklings were 1.5 (95% CI ¼ 0.8-2.8) times more likely to die when the percentage of seasonal basins containing water (WETSEAS) was 18% than when WETSEAS was .40%. An interaction between duckling age and occurrence of rain on the current or 2 previous days indicated that rain effects were pronounced when ducklings were 0-7 days old but negligible when they were 8-30 days old. The TMIN (mean daily minimum temperature on the current and 2 previous days) effects generally were consistent between duckling age classes, and the risk of duckling death increased 9.3% for each 18C decrease in TMIN across both age classes. Overall, the 30-day survival rate of ducklings equipped with radiotransmitters was about 0.23 lower than the survival rate of those without radiotransmitters. Unmarked ducklings were 7.6 (95% CI ¼ 2.7-21.3) times more likely to die on any given day when WETSEAS was 18% than when WETSEAS was .40%. Higher duckling survival and increased use of seasonal wetlands during the wet period suggest that mallard production will benefit from programs that conserve and restore seasonal wetland habitat. Given adverse effects of low temperatures on duckling survival, managers may want to include this stochastic variable in models used to predict annual production of mallards in the Prairie
Siliceous sponges can synthesize poly(silicate) for their spicules enzymatically using silicatein... more Siliceous sponges can synthesize poly(silicate) for their spicules enzymatically using silicatein. We found that silicatein exists in silica-filled cell organelles (silicasomes) that transport the enzyme to the spicules. We show for the first time that recombinant silicatein acts as a silica polymerase and also as a silica esterase. The enzymatic polymerization/polycondensation of silicic acid follows a distinct course. In addition, we show that silicatein cleaves the ester-like bond in bis(p-aminophenoxy)-dimethylsilane. Enzymatic parameters for silica esterase activity are given. The reaction is completely blocked by sodium hexafluorosilicate and E-64. We consider that the dual function of silicatein (silica polymerase and silica esterase) will be useful for the rational synthesis of structured new silica biomaterials.
Progress in molecular and subcellular biology, 2009
Silica-based materials are used in many high-tech products including microelectronics, optoelectr... more Silica-based materials are used in many high-tech products including microelectronics, optoelectronics, and catalysts. Siliceous sponges (Demospongiae and Hexactinellida) are unique in their ability to synthesize silica enzymatically. We have cloned the silica-forming enzymes, silicateins, from both demosponges (marine and freshwater sponges) and hexactinellid sponges. The recombinant enzymes allow the synthesis of silica under environmentally benign ambient conditions, while the technical (chemical) production of silica commonly requires high temperatures and pressures, and extremes of pH. Silicateins can be used for the fabrication of highly-ordered inorganic-organic composite materials with defined optical, electrical, and mechanical properties. The simple self-assembly properties of silicateins which are able to form silica and other metal oxides in aqueous solution allow the development of novel products in nano(bio)technology, medicine, and dentistry.
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