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Changes in fire intensity have carry‐over effects on plant responses after the next fire in southern C alifornia chaparral
Author(s) -
Moreno José M.,
Torres Iván,
Luna Belén,
Oechel Walter C.,
Keeley Jon E.
Publication year - 2013
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.1111/j.1654-1103.2012.01466.x
Subject(s) - chaparral , intensity (physics) , ecology , environmental science , fire ecology , woody plant , forestry , biology , geography , ecosystem , physics , quantum mechanics
Question Do variations in fire intensity within a stand determine changes in fire intensity and plant demographics in a subsequent fire? Location S an D iego ( CA , USA ); chaparral dominated by A denostoma fasciculatum (resprouter) and C eanothus greggii (seeder). Methods In 2003, a wildfire burned a young (16‐yr‐old) stand containing a set of experimental plots burned in 1987 with various levels of fire intensity. In 2004, all the 1987 plots were sampled for A denostoma survival and the recruitment of both species. Similar measures were carried out in the adjacent old (75‐yr) stand. Fire intensity in 2003 was estimated by a surrogate fire severity measure [minimum diameter of burned branches (branch diameter)]. Results In the young stand, branch diameter in 2003 was similar to the control plots in 1987, but lower than in the old stand. Fire intensity in 1987 did not significantly affect branch diameter in 2003. Survival of A denostoma in the young stand was very low, much lower than after the 1987 burn and that in the old stand. Fire intensity in 1987 did not affect A denostoma survival. Recruitment in A denostoma increased, and in C eanothus decreased, with increased fire intensity in 1987. Conclusions We demonstrate that there is a carry‐over effect of fire intensity across a whole fire cycle on plant recruitment of the two dominant species. The 2003 fire partially reversed the relative effects on recruitment caused by elevated fire intensity in 1987. Arguably, this effect was driven by the contrasted relationships of the two species to fire intensity. A denostoma survival in the young stand was much lower in 2003 than in 1987, despite similar branch diameter, and was also lower than in the old stand, despite higher branch diameter in this case. The causes of such mortality are unknown.