Cape Town - "There are tremors within the Democratic Alliance," an analyst said on Monday, following Cape Town Mayor Patricia de Lille's resignation as the party’s provincial leader.University of Stellenbosch School of Public Leadership’s Professor Erwin Schwella believes there is more to De Lille’s resignation, which she announced in the media on Monday morning, saying she wanted to focus more on her mayoral duties."It is still not an earthquake, but there are tremors within the DA," said Schwella.He said the DA was one party that was able to manage its internal squabbles."There was a lot of contestation around the appointments of the Mayoral Committee Members…"He said this indicated that there were issues in the party."The fact that she [De Lille] makes it explicit that she is not going to run for the position of provincial premier [in 2019] says something. I think in the provincial party there may have been concerns that she was appointed as the provincial leader, with the idea that she would remain as mayor and that after her term the position gets reconsidered.READ: 'I am not afraid of any battle' – De Lille on stepping down as provincial DA leader'Astute politician'"However, there might have also been indications in the party that she might have been [becoming] more ambitious, which she now has to clear up and make dead certain that that particular inference is not there, because it does create the possibility for internal conflict with other aspirant provincial leaders."When asked if there had perhaps been a fall out among the leaders, Schwella said there was always a need to "show a united front" because rifts in parties, and people having their own political agendas, could be potentially disruptive.He said all political parties frame the argument in a particular way “when these sorts of things happen”."Ms De Lille is a very astute politician and she decided... to make herself available as the provincial leader of the party, knowing full well that she would become the mayor of Cape Town."The question then is, what has changed, asked Schwella.'Younger leader'Political analyst Ralph Mathekga said De Lille’s unexpected resignation could be a sign that the party was looking toward the 2019 general elections."My sense was that she is stepping aside. I think there is a deliberate effort within the DA to try and bring in younger people," Mathekga said."My outlook is that maybe it will pave the way for a younger leader with more energy to take the party forward, and that might just be the game plan within the DA."He said the average age for a political leader across South Africa's political parties is 61.De Lille, 65, had had an illustrious career as one of the "mothers of South African democracy", he said. Some of her achievements include exposing the arms deal in 1999 in Parliament and serving two terms as Cape Town mayor."With the absence of any other explanation, I think we can say that De Lille maybe feels she has done all she can. She has had a very interesting political journey and will allow younger people to take the party forward."2019 in viewHe said that South Africans - and Africans in general - were not used to leaders stepping down of their own accord and with grace, and said the practice should become more common."At some point when you're a leader you realise you just can't take things forward. There will always be reasons, of course, around whatever internal wrangles, but at the end of the day, the space is now there for a younger leader in the party [to emerge]."He said the DA was now positioning itself for the 2019 elections.The party historically did not have a problem in the Western Cape, and the DA would now look to consolidate their position in the province, he said.DA federal executive chairperson James Selfe told News24 that provincial deputy leader Bonginkosi Madikizela would serve in the interim until the next provincial congress, which is meant to be in February.Selfe said the party had not yet decided on timelines, but would know next week when the next provincial congress would be called.