Digital Images for Plant Phenology Documentation
Tóm tắt
Plant phenology is a key indicator of changing climatic conditions and, thus, automated documentation of phenology using cameras has recently been advocated. The present study, therefore, aimed at identifying phenological stages in Sapium sebiferum using digital images of a full calendar year. Red, Green and Blue channel information from these images was analyzed. Across the three channels (i.e. R, G, and B) the DN values ranged from a minimum of 71.42 in blue channel (BDN) to 156.16 in green channel (GDN). In general, the RDN, GDN, and BDN values increased till 66 DOY after which there was a steep decline in DN values of R, G, and B channels till 224 DOY. After this, a slight increase in the DN values of all the three channels was observed. The value of Red Fraction ranged between 0.297348281 and 0.352612071. The minimum value for the same was on 3 DOY while the maximum was on 135 DOY. On the other hand, the value of Green Fraction ranged between 0.330045461 and 0.39841947. The values of Green Excess Index (2G-RBi) ranged between −0.009863618 and 0.19525841. It reported minimum value on 42 DOY and the maximum on 139 DOY. Green excess index were found to be reliable indicator of greening up in the species. Red Faction was a good indicator of senescence. Photographs provide an ideal tool for documenting phenology of a species and can provide inputs for large scale satellite image analyses.
Tài liệu tham khảo
Lieth HH (1976) Contributions to phenology seasonality research. Int J Biometeorol 20:197–199
Menzel A (2002) Phenology—its importance to global climate change community. Clim Change 54:379–385
Bradley NL, Leopold AC, Ross J, Huffaker W (1999) Phenological changes reflect climate change in Wisconsin. Proc Natl Acad Sci USA 96(17):9701–9704
Menzel A, Sparks TH, Estrella N, Koch E, Aasa A et al (2006) European phenological response to climate change matches the warming pattern. Glob Change Biol 12(10):1969–1976
Cleland EE, Chuine I, Menzel A, Mooney HA, Schwartz MD (2007) Shifting plant phenology in response to global change. Trends Ecol Evol 22(7):357–365
Fitter AH, Fitter RSR (2002) Rapid changes in flowering time in British plants. Science 296(5573):1689–1691
Ellwood ER, Temple SA, Primack RB, Bradley NL, Davis CC (2013) Record-breaking early flowering in the Eastern United States. PLoS ONE 8(1):e53788
Keeling CD, Chin JFS, Whorf TP (1996) Increased activity of northern vegetation inferred from atmospheric CO2 measurements. Nature 382:146–149
Myneni RB, Keeling CD, Tucker CJ, Asrar G, Nemani RR (1997) Increased plant growth in the northern high latitudes from 1981 to 1991. Nature 386:698–702
Chukrina G, Schimel D, Braswell BH, Xiao XM (2005) Spatial analysis of growing season length control over net ecosystem exchange. Glob Change Biol 11:1777–1787
Zhou LM, Tucker CJ, Kaufmann RK, Slayback D, Shabanov NV, Myneni RB (2001) Variations in northern vegetation activity inferred from satellite data of vegetation index during 1981–1999. J Geophys Res Atmos 106:20069–20083
Sparks TH, Huber K, Croxton PJ (2006) Plant development scores from fixed-date photographs: the influence of weather variables and recorder experience. Int J Biometeorol 50:275–279
Uniyal SK (2014) Who will collect and name them. Biodivers Conserv 23:511–512
Crimmins MA, Crimmins TM (2008) Monitoring plant phenology using digital repeat photography. Environ Manag 41:949–958
Zhao J, Zhang Y, Tan Z, Song Q, Liang N, Yu L, Zhao Y (2012) Using digital cameras for comparative phenological monitoring in an evergreen broad-leaved forest and a seasonal rain forest. Ecol Inform 10:65–72
Brandhorst AL, Pinkhof M (1935) Exact determination of phytophenological stages. Acte Phaenol 3:101–109
Rich PM, Clark DB, Clark DA, Oberbauer SF (1993) Long-term study of solar radiation regimes in a tropical wet forest using quantum sensors and hemispherical photography. Agric For Meteorol 65:107–127
Adamsen FJ, Pinter PJ, Barnes EM, LaMorte RL, Wall GW, Leavitt SW, Kimball BA (1999) Measuring wheat senescence using a digital camera. Crop Sci 39:719–724
Richardson AD, Jenkins JP, Braswell BH, Hollinger DY, Ollinger SV, Smith M (2007) Use of digital webcam images to track spring green-up in a deciduous broadleaf forest. Oecologia 152:323–334
Ahrends HE, Brugger R, Stocklii R, Schenk J, Michna P, Jeanneret F, Wanner H, Eugster W (2008) Quantitative phenological observations of a mixed beech forest in northern Switzerland with digital photography. J Geophys Res 113:G04004
Ide R, Oguma H (2010) Use of digital cameras for phenological observations. Ecol Inform 5(5):339–347