Banca de QUALIFICAÇÃO: ANDRÉ YURI SANTOS PORTIOLE BELO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANDRÉ YURI SANTOS PORTIOLE BELO
DATE: 21/03/2025
TIME: 08:30
LOCAL: Google Meet (https://meet.google.com/co a-dnrk-tag)
TITLE:

Dynamics of Litter Decomposition in Habitats: interactions between species, litter diversity and trait responses to biotic and abiotic factors

KEY WORDS:

Litter Decomposition; Mixing Effects; Habitat Heterogeneity; Functional Traits; Biotic-Abiotic Gradients; Interspecific Interactions.

PAGES: 80
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Litter decomposition is an essential ecological process for nutrient cycling, regulated by complex interactions between biotic and abiotic factors, whose context-dependent modulation is still poorly understood. Here, we investigated how spatial heterogeneity, seasonality, and litter quality and functional diversity influence decomposition dynamics in habitats with distinct factors that modulate decomposition. Using experimental approaches based on the use of litterbags, we evaluated: (1) the context-dependence of the effects of leaf litter mixing of inquiline species on the decomposition of a keystone species, (2) the interactive role of habitat diversity and detritus diversity in decomposition, and (3) the predictive power of litter functional attributes (i.e., traits) in predicting litter decomposition under biotic-dominated vs. abiotic-dominated conditions. In chapter 1, we evaluated how the decomposition of the key habitatforming species Encholirium spectabile (Macambira-de-flecha) is affected by the litter of inquiline species in three habitat conditions associated with E. spectabile thickets—inside, edge, and outside the macambira thickets—under seasonal variation in dry and rainy season regimes. The results indicated that inside the thickets (microclimate with lower and more stable temperatures), mixtures with leaves of inquiline species accelerated decomposition in the dry season, possibly because the habitat provides better conditions for the establishment of decomposers during dry periods. At the edge (with temperature and light variation),

under the same seasonal regime, the decomposition of the macambira was also accelerated, indicating complementarity between biotic decomposition and photodegradation. Outside the thickets (high temperature variation and constant light), the decomposition of the macambira litter was inhibited (i.e., slowed down) in the presence of the litter of the inquiline species, due to a possible interference of the release of compounds that inhibit decomposers, as well as to shading that hindered the photodegradation process. In chapter 2, we tested how the effects of litter diversity are modulated by habitat diversity. Our results demonstrated that at the level of the mixture as a whole, habitat diversity positively affected the decomposition of monocultures and negatively affected the decomposition of mixtures. This pattern must have occurred because habitat diversity nullified or reduced patterns of complementarity of the litter mixture. On the other hand, at the species-specific level, there were patterns of decomposition dependent on habitat diversity. These results reveal possible mechanisms dependent on habitat diversity, in addition to those described only by litter diversity. Finally, in chapter 3, we identified the chemical and physical traits that best predict decomposition in habitats dominated by biotic vs. abiotic factors, as well as those that best predict decomposition and the difference in decomposition rate between habitats. We observed that, in habitats where biotic factors predominate, decomposition was associated with traits related to palatability for decomposers. In habitats under strong influence of abiotic factors, in addition to chemical traits, physical traits were critical for litter decomposition. Furthermore, the traits that best explained the difference between decomposition in habitats were linked to the habitat that decomposed the most litter. In summary, our results demonstrate that the mixing effects and the relevance of specific traits are highly context-dependent, being modulated by the interaction between detritus diversity, habitat heterogeneity, and environmental factors. Through these results, we observe the importance of integrating spatial, seasonal, and functional scales in predictive models of the decomposition process.

COMMITTEE MEMBERS:
Presidente - 1714892 - ADRIANO CALIMAN FERREIRA DA SILVA
Interna - 1434166 - LUCIANA SILVA CARNEIRO
Externo à Instituição - ANDERSON DA ROCHA GRIPP - IFRJ