… Thanks to its unique geographical intersection of ocean, mountains, deserts, wetlands and urban development, San Diego County is recognized as the most biologically diverse county in the continental United States, according to the Nature Conservancy. That’s the subject of “Nature — San Diego: America’s Wildest City,” which premieres at 8 p.m. Wednesday on PBS stations and the PBS app. A giant-screen version of the film, titled “Wild San Diego,” will follow on Nov. 22 for a seven-year engagement at the San Diego Natural History Museum. … The film looks at a handful of wildlife species that are not only native to San Diego County but that also have either adapted to, or been hurt by, the presence of humans, who arrived in this region 12,000 years ago and have increased 500-fold in number to 3.3 million over the past 100 years. The greatest influence humans have had on wildlife, the documentary says, is how we manage our water resources.