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Distance and size matters: A comparison of six wildlife camera traps and their usefulness for wild birds 下载免费PDF全文
Camera traps are increasingly used in ecological research. However, tests of their performance are scarce. It is already known from previous work that camera traps frequently fail to capture visits by animals. This can lead to a misinterpretation of ecological results such as density estimates or predation events. While previous work is mainly based on mammals, for birds, no data about if and how camera traps can be successfully used to estimate species diversity or density are available. Hence, the goal of our study was an empirical validation of six different camera traps in the field. We observed a total number of N = 4567 events (independent visits of a bird) in 100 different sessions from March 2017 until January 2018 while camera traps were deployed. In addition, N = 641 events are based on a comparison of the two close‐up camera traps especially designed for birds. These events were all directly observed by the authors. Thus, the cameras can be compared against the human observer. To give an overall assessment and a more generalizable result, we combined the data from the six camera traps and showed that bird size category (effect size = 0.207) and distance (effect size = 0.132) are the most important predictors for a successful trigger. Also, temperature had a small effect, and flock size had an impact with larger flocks being captured more often. The approach of the bird, whether it approached the camera frontally or laterally had no influence. In Table 8 , we give some recommendations, based on our results, at which distances camera traps should be placed to get a 25%, 50%, and 75% capture rate for a given bird size. 相似文献
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Influence of plasmalogen deficiency on membrane fluidity of human skin fibroblasts: a fluorescence anisotropy study 总被引:3,自引:0,他引:3
A Hermetter B Rainer E Ivessa E Kalb J Loidl A Roscher F Paltauf 《Biochimica et biophysica acta》1989,978(1):151-157
The influence of plasmalogen deficiency on membrane lipid mobility was determined by measuring fluorescence anisotropy of trimethylammoniumdiphenylhexatriene (TMA-DPH) and diphenylhexatrienylpropanoylhydrazylstachyose (glyco-DPH) inserted in the plasma membranes of human skin fibroblasts deficient in plasmalogens. The cells used were from patients affected with cerebrohepatorenal (Zellweger) syndrome (CHRS) or rhizomelic chondrodysplasia punctata. Their plasmalogen content (0-5% of total phospholipid) is significantly reduced compared with that of control cells from healthy donors (13-15% of total phospholipid) or of CHRS fibroblasts supplemented with the plasmalogen precursor, hexadecylglycerol. Plasmalogen-deficient cells consistently showed lower fluorescence anisotropies of membrane-bound DPH fluorophores corresponding to higher membrane lipid mobilities as compared to controls. However, very similar lipid mobilities were found for sonicated aqueous dispersions of phospholipids extracted either from CHRS or control cells. Therefore, the differences observed with living cells are not due to differences in the overall physical properties of the membrane lipid constituents. Other phenomena such as lipid asymmetry and/or plasmalogen-protein interactions may be responsible for the effects observed in the biomembranes. 相似文献
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Accuracy of the AVHRR vegetation index as a predictor of biomass,primary productivity and net CO2 flux 总被引:5,自引:0,他引:5
The Normalized Difference Vegetation Index (NDVI) or greenness index, based on the Advanced Very High Resolution Radiometer (AVHRR) aboard the NOAA-7 satellite, has been widely interpreted as a measure of regional to global vegetation patterns. This study provides the first rigorous, quantitative evaluation of global relationships between the NDVI and geographically representative vegetation data-bases, including field metabolic measurements and carbon-balance results from global simulation models. Geographic reliability of the NDVI is judged by comparing NDVI values for different surface types with a general global trend and by statistical analysis of relationships to biomass amounts, net and gross primary productivity, and actual evapotranspiration. NDVI data appear to be relatively reliable predictors of primary productivity except in areas of complex terrain, for seasonal values at high latitudes, and in extreme deserts. The strength of the NDVI-productivity relationship seems comparable to that of earlier climate-based productivity models. Little consistent relationship was found, across different vegetation types, between NDVI and biomass amounts or net biospheric CO2 flux.Abbreviations AET=
Actual Evapotranspiration
- AVHRR=
Advanced Very High Resolution Radiometer
- GPP=
Gross Primary Production
- GVI=
Global Vegetation Index
- NDVI=
Normalized Difference Vegetation Index
- NPP=
Net Primary Production 相似文献
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Nucleotide sequence analysis of the lemur beta-globin gene family: evidence for major rate fluctuations in globin polypeptide evolution 总被引:1,自引:0,他引:1
Lemur beta-related globin genes have been isolated and sequenced. Orthology
of prosimian and human epsilon-, gamma-, and beta-related globin genes was
established by dot-matrix analysis. All of these lemur globin genes
potentially encode functional beta-related globin polypeptides, though
precisely when the gamma-globin gene is expressed remains unknown. The
organization of the 18-kb brown lemur beta-globin gene cluster (5'
epsilon-gamma-[psi eta-delta]-beta 3') is consistent with its evolution by
contraction via unequal crossing-over from the putative ancestral mammalian
beta-globin gene cluster (5' epsilon-gamma- eta-delta-beta 3'). The dwarf
lemur nonadult globin genes are arranged as in the brown lemur. Similar
levels of synonymous (silent) nucleotide substitutions and noncoding DNA
sequence differences have accumulated between species in all of these
genes, suggesting a uniform rate of noncoding DNA divergence throughout
primate beta-globin gene clusters. These differences are comparable with
those observed in the nonfunctional psi eta pseudogene and have therefore
accumulated at the presumably maximal neutral rate. In contrast,
nonsynonymous (replacement) nucleotide substitutions show a significant
heterogeneity in distribution for both the same gene in different lineages
and different genes in the same lineage. These major fluctuations in
replacement but not silent substitution rates cannot be attributed to
changes in mutation rate, suggesting that changes in the rate of globin
polypeptide evolution in primates is not governed solely by variable
mutation rates.
相似文献
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Diagnoses of three corticolous species of Discolichenes from Hawaii are presented:Bacidia violascens K. Kalb etVězda sp. n.,Dimerella degeneri K. Kalb etVězda sp. n. andD. frederici K. Kalb sp. n. The isotypes will be distributed in fasc. No. 70 of the “Lichenes selecti exsiccati” (issued by the Botanical Institute, Czechoslovak Academy of Sciences, Pr?honice near Praha). 相似文献
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