Post-fire straw mulching is widely used to reduce soil erosion and facilitate vegetation recovery in fire-affected ecosystems. However, straw mulch may introduce agricultural weedy species, raising concerns about their persistence and potential effects on post-fire plant community assembly. This study evaluated the medium-term ecological implications of straw mulch application using a post-fire chronosequence in semi-arid Mediterranean ecosystems of southeastern Spain. Vegetation was surveyed in 54 plots (27 mulched and 27 untreated) distributed across sites representing 1, 2 and 6 years after fire (YAF). Species richness, diversity, composition and the abundance of agricultural weedy species were analysed to assess treatment effects across the chronosequence. Straw mulching was associated with higher species richness and diversity at the early post-fire stages, through the introduction of agricultural weedy species. Community composition differed significantly among post-fire stages and between treatments, although post-fire stage explained a substantially larger proportion of the variation than mulching treatment. Agricultural weedy species were more abundant at the early post-fire stages but showed very low abundance at the site representing 6 YAF. Plant communities in mulched and untreated plots became more similar at the latest stage represented in the chronosequence. Overall, the results suggest that straw mulching may enhance plant diversity during early post-fire recovery without evidence of substantial negative medium-term effects on vegetation composition under the conditions evaluated in this study. These findings support the use of straw mulching as a post-fire management measure with limited medium-term impacts on plant community composition.
Coral reef ecosystems worldwide are undergoing continuous degradation, making active restoration an increasingly important strategy for promoting recovery. However, the effects of different species configuration strategies in large-scale coral restoration remain poorly understood. We deployed 216 framed reef modules around Wuzhizhou Island (northern South China Sea) to test the effects of monoculture vs. polyculture on coral survival, growth, physiological parameters and associated microbial communities. The experiment involved three reef-building corals, Acropora hyacinthus, Acropora microphthalma, Porites cylindrica, transplanted under both configurations. During the 201-day experimental period, all species maintained high survival rates (>80%) under both treatments, whereas growth responses were species specific. Monoculture transplantation significantly enhanced the growth of A. hyacinthus and A. microphthalma, but had no significant difference on P. cylindrica. Total biomass was higher under monoculture in A. hyacinthus (P < 0.001) and A. microphthalma (P = 0.018), but higher under polyculture in P. cylindrica (P = 0.001), while Fv/fm and Symbiodiniaceae density were primarily influenced by time. Microbial community structure was primarily driven by host species during the early transplantation stage, whereas by day 201, polyculture influenced microbial diversity, genus-level composition, and co-occurrence network complexity, particularly in A. microphthalma and P. cylindrica. These findings demonstrate that transplantation configuration strategies can influence coral growth dynamics and microbial communities, suggesting that polyculture may enhance microbial network connectivity, with potential implications for ecological redundancy and stability. These findings reflect responses over the 201-day experimental period, and longer-term studies are needed to determine whether these species-specific effects persist during subsequent restoration stages.
