Greening of the Arctic:

Transcription

1 Greening of the Arctic: A planet-to-plant analysis of tundra vegetation change Focus on the Yamal Peninsula, Russia D.A. Walker, H.E. Epstein, U.S. Bhatt, H. A. Maier, G.V. Frost, M.K. Raynolds, J. Comiso, R. Daanen, D.S. Drozdov, B. Forbes, A.A. Gubarkov, G. Jia, E. Kaarlejarvi, O. Khitun, A.V. Khomutov, P. Kuss, M.O. Leibman, G. Matyshak, N.G. Moskalenko, P. Orekhov, J.E. Pinzon, V.E. Romanovsky, C.J. Tucker, N.G. Ukraintseva, Q. Yu State of the Arctic Meeting, Miami, Mar 2010 Yamal Peninsula, Russia Photo: D.A. Walker

2 Goal of GOA: Examine trends of vegetation, climate, and greening (NDVI) along two transects through all 5 Arctic bioclimate subzones!"#$% &'()% %*+,%% %!-."#/%% 0 % %;<:*=3* */#/)% 1% % %:<>*=3 *0?#+(?'()*1@'?A<+B?,-+* 2 * *><C*=3 *B)&"<0?#+(?'()*1@'?A*+B?,-+* 3 * *C<D*=3 *)?)$(*1@'?A<+B?,-+* 4 % %D<;8*=3 *%#@<+B?,-+*!"#$%"&'()*+,-.#/)+*'+*&'00)1*-2*3456* 7)'&*899:* 4%#/E*(B)*(,/1?'*-"#$%"&'()*E?'1")/(F** ;9=*3*$B'/E)*"/*(B)*6G7** ;9<A#%1*$B'/E)*"/*.#/'%*-"#&'++** ;9<A#%1*$B'/E)*"/*0?#1,$HI"(2* >*(#*;9<A#%1*$B'/E)*"/*I'+$,%'?<0%'/(* 1"I)?+"(2*

3 Results of the North American Arctic Transect were published in JGR special issue. J'%K)?*)(*'%L*899ML*GNO*

4 This talk focuses on the Yamal Transect Hierarchy NDVI analyses AVHRR (12.5 km and 50 km) AVHRR (1 km) Landsat ETM+ (15 m) Quickbird (60-cm resolution) Hand-held measurements of NDVI along Yamal transect Ground observations along the Yamal transect Vegetation analysis, relationship of NDVI to vegetation The roles of climate, substrate and disturbance along the Yamal transect. P*

5 Much of project focuses on greenness patterns and change using the Normalized Difference Vegetation Index (NDVI) NDVI = (NIR-R)/(NIR + R). The difference between the reflectance in the NIR and R portions of the spectrum is a measure of the photosynthetic capacity of the surface. The difference is divided by the sum of the reflectances to adjust for variations in the index due to slope and shadows. >*

6 Circumpolar changes to early summer coastal sea ice, and summer land temperatures ( )Percentage MaxNDVI change Arctic wide: +5% Much greater change in North America (+9%) than in Eurasia (+3%). Bhatt et al in revision, Earth Interactions. Large increases in (10-15%) in the High Arctic (northern Canada and Greenland) and the Beaufort Sea area. Other analyses (not shown) revealed strong positive correlations between NDVI and land temperatures and strong negative correlations with the percentage of coastal sea ice.

7 Yamal 1-km AVHRR NDVI derived from CAVM data set '%#/E*(B)*-"#$%"&'()* E?'1")/(U*$#&0'?)1*(#*(B)* $"?$,&0#%'?*4?$H$L* USGS data set used for the CAVM 6LVL*O'2/#%1+L*89;9L*W'&'%*X3XY3*J#?K+B#0L*O#I'/")&"U*ZS** C* C*

8 Analysis of NDVI with Landscape #'"(98.:)/% 6#+(*I'?"'H#/*"+*?)%'()1*(#*+#"%*()[(,?)*\+'/1+* I+L*%#'&2*+#"%+]L*!?#'1*?"I)?*$B'//)%+*B'I)*B"EB)+(*QR5S*1)+0"()* %'?E)*'&#,/(*#A*%'K)+*"/*(B)*I'%%)2+L* ;<K&*1'('*"+*/#(*^/)*)/#,EB*(#*?)+#%I)*(B)* /':5%<)E<".)% 6LVL*O'2/#%1+L*89;9L*W'&'%*X3XY3*J#?K+B#0L*O#I'/")&"U*ZS** M* M*

9 Yamal Transect ( ) Forest-tundra transition: Nadym (2007) and Kharp (2009) Subzone E: Laborovaya (2007) Subzone D: Vaskiny Dachi (2007) Subzone C: Kharasavey (2008) Subzone B: Ostrov Belyy (2009) O)1*%"/)*"+*(B)*899D*B)%"$#0()?*0'(BL* D*

10 Data collected Transects QR5S*'/1*X4S* _0)$")+*$#I)?* 4$HI)*%'2)?*1)0(B* Plots Soils 3#I)?*'-,/1'/$)U*+"()*A'$(#?+*!"#&'++* Q<A'$(#?* _#"%*0"(*0?#^%)*1)+$?"0H#/+* _#"%*$B)&"$'%*'/1*0B2+"$'%* '/'%2+)+* ;9*

11 Yamal transect biomass,'<85%5:p)%8(9%9)89%8#'p)$;.'"(9%#:'d8//%:(>5"9:(;%<.))/% %%%%%&'(85%%5'8D7% /:<)/%% Zonal sites show little variation across the peninsula, except in subzone E. 1:'D8//%KL%DMNO%,'<85%5:P)%8#'P)$;.'"(9%#:'D8//% Biomass values for zonal site in subzone E is close to tussock tundra values for Alaska (! 750 g m^2). %%%%S(9)./<'.7%'(57% %%%%%&'(85%%5'8D7%/:<)/%%!"#Q'()%%%%%%%%%%%%%%%%%%%%%%%%%%%%%R,%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%4%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%3%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%2%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%1% Total live biomass values of zonal loamy sites in subzones C and D are close published values for mesic tundra Barrow and Prudhoe Bay (! 450 g m^2). ;;*

12 Relation of NDVI to vegetation and environmental variables Ordination analysis shows the relationship of the study plots to each other based on floristic similarity. And with respect to environmental and plant variables (cover, biomass, GG*Z?#+(*)(*'%L*89;9U*W'&'%*X3XY3*J#?K+B#0*

13 Relationships between hand-held NDVI measurements and other variables 9LD* 9LM* 9LC* 9Lc* 9L>* 9LP* 9L:* 9L8* 9L;* 2*`*9L98P8[*a*9L>9;C* Ob*`*9L:9PM* 9* >* ;9* ;>* 9LD* 9LM* 9LC* 9Lc* 9L>* 9LP* 9L:* 9L8* 9L;* D':/<".)% 2*`*9L99P:[*a*9LPc>>* Ob*`*9L8>;c8* 9* 89* P9* c9* M9* ;* 9LM* 9Lc* 9LP* 9L8* 2*`*9L999P[*a*9L>:* Ob*`*9L8PDD;* 9* 899* P99* ;* 9LM* 9Lc* 9LP* 9L8* 2*`*9L99C[*a*9L>;9;* Ob*`*9L;MDD* 9* ;9* 89* :9* 242%KD)TUVWW%;O% )I)?E?))/*+B?,-+U*'$?#$'?0#,+*&#++)+U*1)$"1,#,+*+B?,-+U*X4SU*&#++*B)"EB(U*#?E'/"$* (B"$K/)++]L** 4%+#*+(?#/E*)/I"?#/&)/('%*$#??)%'H#/+*\)LEL*I#%L*+#"%*&#"+(,?)U*0$(L*+'/1U*%'H(,1)U* ;:*

14 Disturbance has major effect on NDVI patterns but it is hard to partition the various effects Overgrazing" Trampling" Effects of reindeer* Grassification" Wind erosion" e/h?)*0)/"/+,%'*"+*b)'i"%2*e?'.)1* '(*0?)+)/(*-)$',+)*#A*%'$K*#A* $#/(?#%*'?)'+*(#*+(,12*(B)*)f)$(+* \)[$%#+,?)+]L* d#()/h'%*&'g#?*)f)$(*"/*+'/12* '?)'+L* db#(#+f**!?,$)*z#?-)+l*

15 Strong greening on landslide slopes cover extensive areas of the Yamal. Landslides and cryogenic erosion X'?E)*)f)$(*#/*0'T)?/+*#A*E?))//)++*"/*&'/2* '?)'+L** h,'/h('hi)*&)'+,?)+*#a*a?)?i,)/$2*#a*+%"1)+*'?)* /))1)1*(#*1)()?&"/)*)f)$(+*#/*?)E"#/'%*E?))/"/E* (?)/1+L* Q))1*()&0#?'%*+)?")+*#A*B"EB<?)+#%,H#/*+'()%%"()* "&'E)+*'/1j#?*0B#(#+*"/*%'/1+%"1)*'?)'+*(#*'++)++* (B)*?'()*#A*$B'/E)L 1:'D8//%!)A#?)* %'/1+%"1)+* 4k)?**%'/1+%"1)+* Low-willow shrublands develop on landslides during 200-yr succession, greatly changing biomass and NDVI. Key: A stable areas B shear surface C landslide body 1 young landslide 2 old landslide 3 very old landslide Photos D.A. Walker YK?'"/(+)I'*'/1*X)"-&'/*)(*'%L*8999U*899CU*899M*

16 Impacts of gas development d#()/h'%*%'?e)*)f)$(+* #/*?)"/1))?*'++)++*(#*?'/E)%'/1+L* X#$'%%2*"&0#?('/(* )f)$(+*#/*qr5s*-,(*+h%%*?)%'hi)%2*+&'%%*)[()/(l* Q))1*1)I)%#0&)/(* +$)/'?"#*&#1)%+*(#*B)%0* 0?)1"$(*'/1*0%'/*A#?* )[0'/+"#/*#A*?#'1* Brigade 4: 225 km 2 out of total 1019 km 2 summer pasture Brigade 8: 200 km 2 out of total 796 km 2 summer pasture 7"&#*V,&0,%'F*W'&'%*X3XY3*J#?K+B#0U*6#+$#@U*8M<:9*G'/*899ML**

17 !"#"$%&'&()*)+,&-./0& 1)23452#6&'&7)89& :;;<& =%8+>?3"8"#& $" $" #" #"!"!" d'/$b?#&'h$<+b'?0)/)1*c9<$&*?)+#%,h#/*h,"$k-"?1*"&'e)+*0?#i"1)* (B)*0%'/(*%)I)%U*'/1lLL** 0"$(,?)*#A*0?#1,$HI"(2*0'T)?/+*"/*?)%'H#/+B"0*(#*E)#%#E2U*B21?#%#E2* '/1*0'T)?/)1*E?#,/1L** ;C*

18 Alder has aggressively colonized sites where surface organic horizons were removed by a high-intensity wildfire ~100 years ago. Alder recruitment is concentrated on mineral-dominated frost-boils, where cryogenic disturbance prevents the formation of an organic mat. Could explain the regular spacing of shrubs in open alder shrublands of the Low Arctic. Photo credit Skip Walker

19 Arctic plants respond mainly to changes to their immediate plant environment (summer temperature, moisture, and nutrients) NDVI is a good integrator of the total changes to plant productivity, but is a poor tool for determining the causes. It is usually not possible to ascribe causality to the changes. Vegetation change models can help here. J'%K)?*)(*'%L*899DL*e/I"?#/&)/('%*O)+)'?$B*X)T)?+* ;D*

20 ArcVeg is helping to unravel the effects of various types of disturbance _#"%*Q* _#"%*Q* _#"%*Q* Sensitivity of soil N to warming, grazing, and differences in soils X#'&2*+"()+* H'G%;.8Q:(;% \:;-%;.8Q:(;% _'/12*+"()+* J'?&)?*$%"&'()* Grazing suppresses vegetation response to warming. Herbivory has greater effect in loamy (nutrient-rich) sites. 7"&)* 7"&)* Yu, Q. et al Environmental Research Letters.

21 Credits NSF, ARCSS: Synthesis of Arctic System Science and Seasonality initiatives NASA: LCLUC NEESPI project Russian Academy of Science ENSINOR project