Banca de DEFESA: VERENA HENSCHEN MEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : VERENA HENSCHEN MEIRA
DATA : 17/02/2020
HORA: 09:00
LOCAL: Instituto de Biologia da UFBA
TÍTULO:

Heatwave strike phase shift in coral reefs

PALAVRAS-CHAVES:

regime shift; resilience; stability; alternative state

PÁGINAS: 60
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
SUBÁREA: Ecologia de Ecossistemas
RESUMO:

Phase shift is characterized by an abrupt change in the structure of a community in response to a disturbance that is capable of disrupting system resistance, with the possibility of collapsing it. This phenomenon has been recognized in many ecosystems and has been worrying scientists for half a century who point to human activities as the main cause of phase shift in most studies. However, the reaction of phase shift communities to anthropic disturbances has been neglected by the academic community. In recent decades, heatwaves resulting from climate change have become increasingly frequent and intense, especially affecting coral reefs. As a result, mass coral bleaching events are becoming increasingly recurrent, and are recognized as the major cause of the decline of reef ecosystems on a global scale. In 2019, an unprecedented heatwave hit the Todos os Santos Bay (TSB) coral reefs causing mass coral bleaching to an intensity never recorded in a 34-year historical series. Here, we analyzed the effects of this event on the resistance of TSB reefs in phase shift to the dominance of the zoanthid Palythoa cf variabilis. Using benthic coverage data from 2003, 2007, 2011, 2016, 2017 and 2019, we analyzed 6 TSB reefs: 3 normal and 3 phase shifting. For each reef we estimated coral, zoanthid, P. cf variabilis and Palythoa caribaeorum coverage, and coral bleaching and P. cf variabilis in percentage. Until 2019 mass coral bleaching event, coral cover on normal reefs declined while zoanthid cover did not change, but there was a decrease in zoanthid cover on phase-shifting reefs after the 2019 heatwave. Our results indicate that the resistance of the phase shift reef community was surpassed, leading to a change in its structure. Our work revealed that phase shift reef communities were more susceptible to the heatwave disturbance than normal reef communities.

MEMBROS DA BANCA:
Presidente - 2997144 - IGOR CRISTINO SILVA CRUZ
Interno - 1576452 - RICARDO DOBROVOLSKI
Externo à Instituição - GUILHERME ORTIGARA LONGO - UFRN