The Record She Left Behind

The Zenobians land on Earth after a natural disaster has left floodplains, atmospheric radiation, and other effects all over the globe. Zerera and the other Zenobians from Andromeda are multidimensional beings, which is a problem for Zer, who turns ghostly and/or invisible when not accepted or acknowledged by Earthlings. It's also taboo to influence other peoples.The first Earthling Zer meets is a cougar then her human Earthling contactee, Ian. With Ian, Zer meets Hoover Indians who impart different types of wisdom and inject humor into Zer's life. When she visits the public baths at the Superstitions, she meets (her foster brother's contactee) Karen. They dislike and misunderstand each other.
When Zer and Ian reach Prescott, they find a community protecting itself from thieves, low on food stores, and unable to grow food in the biosphere's current condition. Zer is invisible to the Prescotts, so she takes two siblings, outsiders of the community, to the Isle where she expects a crewmate to alter the siblings' Heritage seed so they can grow properly and she expects to train two juvie Exotica.
The same day that Zer finally meets two of the three saplings she planted from seed, she realizes that Earth children will be the heirs of new Earth. She also realizes it's too late to train the juvie saplings who reached and by-passed that stage of development before Zer got back to the Isle to train them. She has been having adventures with Ian. However, it was her responsibility to train the juveniles and to educate others to train other Exotica. She has not done either, and it's too late. Worse, Brea, a crewmate she mistrusts, planted seed that have grown into seemingly unhealthy saplings.
Meanwhile, Karen stole the last bag of Exotica seed, delivered it to a designated coastal camp and enjoys time with human "Beastie converts" before returning to Prescott to steal building material and other resources. She's caught and argues with Zer.