Post-Fire Dynamics of Cistus spp. in a Pinus brutia Forest

Authors: ÇAĞATAY TAVŞANOĞLU, BEHZAT GÜRKAN

Abstract: The population dynamics of 2 species of Cistus L. (C. salviifolius L. and C. creticus L.) were studied along a post-fire successional gradient in Pinus brutia Ten. forests in Marmaris National Park, Turkey. The population density of Cistus spp. was 16 individual m^{-2} at the end of the first year after fire and then decreased exponentially (r^2 = 0.926, P < 0.001) the second year after fire to later successional stages. Total projected foliage cover of Cistus spp. was 26% by the end of the first year after fire, it increased to approximately 38% during the second year after fire and decreased linearly (r^2 = 0.872, P < 0.01) beyond this time. Rates of establishment of Cistus spp. were high in the first year after fire but were low in subsequent years and most of the Cistus plants flowered during the second year after fire. There was a significant positive relationship between the density of new seedlings of Cistus and cover of Pinus brutia trees in the sixth year after fire (r^2 = 0.242, P = 0.002). Seed yield of Cistus was reduced due to predation of seed capsules by Bruchid insects. Both species of Cistus were shown to be typical post-fire colonisers in terms of timing of recruitment and post-fire population dynamics. The major factors responsible for the decrease in density of seedlings of C. salviifolius and C. creticus are likely to be the mortality of young seedlings due to summer drought and competition among seedlings and with P. brutia trees. It is suggested here that the species considered have fire-dependent establishment behaviour and an increase in population is restricted to early post-disturbance in P. brutia forests in Turkey, as in other Mediterranean regions.

Keywords: Post-fire colonisers, post-fire succession, Cistus creticus, Cistus salviifolius, Turkey

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