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31.
Examining the uncertain origin and management role of martens on Prince of Wales Island,Alaska
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Jonathan N. Pauli Wynne E. Moss Philip J. Manlick Emily D. Fountain Rebecca Kirby Sean M. Sultaire Paula L. Perrig Jorge E. Mendoza John W. Pokallus Timothy H. Heaton 《Conservation biology》2015,29(5):1257-1267
Conservation biologists are generally united in efforts to curtail the spread of non‐native species globally. However, the colonization history of a species is not always certain, and whether a species is considered non‐native or native depends on the conservation benchmark. Such ambiguities have led to inconsistent management. Within the Tongass National Forest of Alaska, the status of American marten (Martes americana) on the largest, most biologically diverse and deforested island, Prince of Wales (POW), is unclear. Ten martens were released to POW in the early 1930s, and it was generally believed to be the founding event, although this has been questioned. The uncertainty surrounding when and how martens colonized POW complicates management, especially because martens were selected as a design species for the Tongass. To explore the history of martens of POW we reviewed other plausible routes of colonization; genetically and isotopically analyzed putative marten fossils deposited in the late Pleistocene and early Holocene to verify marten occupancy of POW; and used contemporary genetic data from martens on POW and the mainland in coalescent simulations to identify the probable source of the present‐day marten population on POW. We found evidence for multiple routes of colonization by forest‐associated mammals beginning in the Holocene, which were likely used by American martens to naturally colonize POW. Although we cannot rule out human‐assisted movement of martens by Alaskan Natives or fur trappers, we suggest that martens be managed for persistence on POW. More generally, our findings illustrate the difficulty of labeling species as non‐native or native, even when genetic and paleo‐ecological data are available, and support the notion that community resilience or species invasiveness should be prioritized when making management decisions rather than more subjective and less certain conservation benchmarks. 相似文献
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Beak DG Kirby JK Hettiarachchi GM Wendling LA McLaughlin MJ Khatiwada R 《Journal of environmental quality》2011,40(3):679-695
The speciation and distribution of Co in soils is poorly understood. This study was conducted using x-ray absorption spectroscopy (XAS) techniques to examine the influence of soluble cobalt in the +2 oxidation state (Co[II]) aging, submergence-dried cycling, and the presence of in vivo rice roots on the speciation and distribution of added Co(II) in soils. In the aging and submerged-dried cycling studies, Co was found to be associated with Mn oxide fraction (23 to 100% of total Co) and Fe oxide fractions (0 to 77% of total Co) of the soils as either Co(II) species or a mixed Co(II), and Co in the +3 oxidation state (Co[III]) species. The surface speciation of Co in the Mn oxide fraction suggests an innersphere complex was present and the speciation of Co in the Fe oxide fraction was an innersphere surface complex. The in vivo root box experiments showed similar Co speciation in the Mn oxide fraction (13 to 76% of total Co) as the aging and submerged-dried cycling studies. However, the Fe oxide fraction of the soil was unimportant in Co retention. A significant amount (24 to 87% of total Co) of the Co in root box treatments was identified as a Co precipitate. The importance of this finding is that in the presence of rice roots, the Co is redistributed to a Co precipitate. This work confirmed earlier macroscopic work that Mn oxides are important in the sequestration of Co in soils and the influence of roots needs to be taken into account when addressing Co speciation. The information gained from this study will be used to improve models to predict the lability and hence the availability of Co in terrestrial environments. 相似文献
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Adrienne L. DuBois Stephen Nowicki William A. Searcy 《Behavioral ecology and sociobiology》2011,65(4):717-726
In aggressive communication, the interests of signalers and receivers are directly opposed, presenting a challenge to the
maintenance of reliable signaling. Index signals, whose production is constrained by physical ability, offer one solution
to the reliable signaling problem. Vocal performance, the ability to produce physically challenging songs, is likely such
a signal in swamp sparrows. Maximum vocal performance varies between males and is correlated with aspects of quality. However,
vocal performance can be modulated in aggressive contexts by increasing the frequency bandwidth and trill rate of songs. This
study examines receiver response to (1) differences in performance of the same song types by different signalers and (2) individual
modulation of performance between contexts. Results demonstrate that male receivers show differential response to between-male
differences in song type performance, but do not show differential response to the smaller scale modulations of performance
produced by individuals singing the same song type at different times. This pattern suggests that vocal performance cannot
be effectively cheated and may therefore serve as a good example of an index signal. 相似文献
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McKenzie JH Alwis KU Sordillo JE Kalluri KS Milton DK 《Journal of environmental monitoring : JEM》2011,13(6):1739-1745
Measurement of environmental endotoxin exposures is complicated by variability encountered using current biological assay methods arising in part from lot-to-lot variability of the Limulus-amebocyte lysate (LAL) reagents. Therefore, we investigated the lot-to-lot repeatability of commercially available recombinant Factor C (rFC) kits as an alternative to LAL. Specifically, we compared endotoxin estimates obtained from rFC assay of twenty indoor dust samples, using four different extraction and assay media, to endotoxin estimates previously obtained by Limulus amebocyte lysate (LAL) assay and amounts of 3-hydroxy fatty acids (3-OHFA) in lipopolysaccharide (LPS) using gas-chromatography mass spectroscopy (GC-MS). We found that lot-to-lot variability of the rFC assay kits does not significantly alter endotoxin estimates in house dust samples when performed using three of the four assay media tested and that choice of assay media significantly altered endotoxin estimates obtained by rFC assay of house dust samples. Our findings demonstrate lot-to-lot reproducibility of rFC assay of environmental samples and suggest that use of rFC assay performed with Tris buffer or water as the extraction and assay medium for measurement of endotoxin in dust samples may be a suitable choice for developing a standardized methodology. 相似文献
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Adrienne I. Greve Jim C. Loftis Juliane B. Brown Rob R. Buirgy Ben Alexander 《Journal of the American Water Resources Association》2003,39(6):1409-1418
ABSTRACT: In 1996, the Big Thompson Watershed Forum (BTWF) was formed “to assess and protect the quality of water” in the Big Thompson Watershed in northern Colorado. However, until 1999, water quality monitoring in the watershed was performed by many state, local, and federal agencies with no coordination among programs and with few efforts toward efficiency, data comparability, or information exchange. To better meet the needs of its stakeholders, the BTWF since 1999 has been actively pursuing the design and implementation of a cooperative water quality monitoring program. The program design involved consensus building among the funding participants, primarily drinking water providers. The final design included 38 parameters to be sampled 15 times per year at 24 stream and canal locations plus two reservoirs. Although the collaborative consensus based approach has been successful for the BTWF, this approach has its drawbacks; most notable among these are the time and labor this approach requires. Also, the BTWF struggled with achieving equal representation of all interests, since those agencies that provided funding had the greatest voice in the final product. While a collaborative approach may not always be best for monitoring program design, it should be appropriate for many watershed organizations that face the common problem of severe financial constraints. 相似文献
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Measurement of nitrogen dioxide using passivediffusion tube over 22 months in Cambridge, U.K. areanalysed as a function of sampler exposure time, andcompared with NO2 concentrations obtained from aco-located chemiluminescence analyser. The averageratios of passive sampler to analyser NO2 at acity centre site (mean NO2 concentration 22 ppb)are 1.27 (n = 22), 1.16 (n = 34) and 1.11 (n = 7) forexposures of 1, 2 and 4-weeks, respectively. Modellingthe generation of extra NO2 arising from chemicalreaction between co-diffusing NO and O3 in thetube gave a ratio (modelled/measured) of 1.31 for1-week exposures. Such overestimation is greatest whenNO2 constitutes, on average, about half of totalNOx (= NO + NO2) at the monitoring locality.Although 4-week exposures gave concentrations whichwere not significantly different from analyserNO2, there was no correlation between thedatasets. At both the city-centre site and anothersemi-rural site (mean NO2 concentration 11 ppb)the average of the aggregate of four consecutive1-week sampler exposures or of two consecutive 2-weeksampler exposures was systematically greater than fora single 4-week exposure.The results indicate two independent and opposingsystematic biases in measurement of NO2 bypassive diffusion sampler: an exposure-timeindependent chemical overestimation with magnitudedetermined by local relative concentrations of NO andO3 to NO2, and an exposure-time dependentreduction in sampling efficiency. The impact of theseand other potential sources of systematic bias on theapplication of passive diffusion tubes for assessingambient concentrations of NO2 in short (1-week)or long (4-week) exposures are discussed in detail. 相似文献