RESUMO
BACKGROUND AND AIMS: Rock outcrop vegetation is distributed worldwide and hosts a diverse and unique flora that evolved under harsh environmental conditions. Unfortunately, seed ecology in such ecosystems has received little attention, especially regarding seed traits, germination responses to abiotic factors and the potential role of phylogenetic relatedness on such features Here, we provide the first quantitative and phylogenetically-informed synthesis of the seed functional ecology of Brazilian rock outcrop vegetation, with a particular focus on quartzitic and ironstone campo rupestre. METHODS: Using a database of functional trait data, we calculated the phylogenetic signal of seven seed traits for 371 taxa and tested whether they varied among growth forms, geographic distribution, and microhabitats. We also conducted meta-analyses that included 4,252 germination records for 102 taxa to assess the effects of light, temperature, and fire-related cues on the germination of campo rupestre species and explored how the aforementioned ecological groups and seed traits modulate germination responses. KEY RESULTS: All traits and germination responses showed a moderate-to-strong phylogenetic signal. Campo rupestre species responded positively to light and had maximum germination between 20-25 ºC. The effect of temperatures beyond this range was moderated by growth form, species geographic distribution, and microhabitat. Seeds exposed to heat shocks above 80 °C lost viability, but smoke accelerated germination. We found a moderating effect of seed mass for in responses to light and heat shocks, with larger, dormant seeds tolerating heat better but less sensitive to light. Species from xeric habitats evolved phenological strategies to synchronise germination during periods of increased soil water availability. CONCLUSIONS: Phylogenetic relatedness plays a major role in shaping seed ecology of Brazilian rock outcrop vegetation. Nevertheless, seed traits and germination responses varied significantly between growth forms, species geographic distribution and microhabitats, providing support to the regeneration niche hypothesis and the role of functional traits in shaping germination in these ecosystems.
RESUMO
Ecological knowledge plays a significant role in ensuring efficient ecological restoration. We conducted a systematic review to assess if sufficient ecological knowledge has been accumulated to aid restoration practices for the Cerrado, a Brazilian biome dominated by savanna ecosystems and threatened by anthropogenic disturbances. Most Cerrado restoration studies were performed by few research groups and focused primarily on two vegetation types: cerrado sensu stricto (typical savanna) and riparian forest. We also found that defining reference ecosystems and selecting plant species for restoration programs is neglected, mostly disregarding their original occurrence and proportion of plant growth forms. Furthermore, studies lacked standardized and systematic evaluation of restoration outcomes. Hence, we argue that current ecological knowledge is insufficient to guarantee the success of large-scale ecological restoration of the Cerrado. We strengthen the need to explicitly define the reference ecosystem for each Cerrado ecosystem and use its structure and composition as guidance for ecological restoration research, which should be based on a scientific approach. We encourage investigations into ecological dynamics and natural regeneration of the different vegetation types of the Cerrado and highlight the importance of integrating such knowledge with environmental laws, societal engagement and cost-effective techniques to advance Cerrado ecological restoration.