Due to multiple impacts, Cystoseira forests are experiencing a significant decline, which is
affecting the ecosystem services they provide. Despite conservation efforts, there is an
urgent need to develop best practices and large-scale restoration strategies. To implement
restoration actions, we developed an ex situ protocol for the cultivation of Cystoseira. amentacea
var. stricta, aimed at reducing the time needed for laboratory culture, thus avoiding
prolonged maintenance and minimizing costs. Specifically, we tested the effects of temperature,
light and substratum on settlement and growth of early life stages using a factorial
experiment. Temperature (20 and 24ÊC) and photoperiod (15L:9D) were selected to reflect
the conditions experienced in the field during the reproductive period. Two light intensities
(125 and 250 μmol photons m−2s−1) were selected to mimic the condition experienced in the
absence of canopy (i.e. barrenÐhigher light intensity) or in the understory (lower light intensity)
during gamete release. The tested substrata were flat polished pebbles and rough clay
tiles. The release of gametes and the successive survival and development of embryo and
germlings were followed for two weeks. Regardless of the culture conditions, rougher tiles
showed higher zygote settlement, but the substrata did not affect the successive development.
Zygote mortality after one week averaged 50% and at the end of the second week,
embryonic survival was higher under lower light and temperature conditions, which also
determined the growth of larger embryos.
