Unless their habitat is preserved, species can go extinct.

First, the polar bear. Next, families with children near Burnet Road.

That's the concern – slightly overstated – voiced by Sustainable Neighborhoods of North Central Austin, a nonprofit citizens group that's pushing the city to protect the interests of households with children in the urban core. While parts of the six areas SN serves – Brentwood, Crestview, Allandale, North Shoal Creek, Wooten, Highland – have plenty of kids now, census data show an overall decline in the percentage of the Central Austin population comprising families with children. Housing availability, affordability, and school quality have pulled families to the edges of town.

Neighborhoods go through natural population cycles, as kids grow up, parents retire and downsize, and new families move in. But SN suggests that new development that skews away from the needs of families can artificially speed up those cycles and destroy the balance. In the immediate future, they'd like to see better sidewalks, bike lanes, and park space along busy streets like Burnet. Longer term, they'd like to see the city encourage a mix of development they call "sustainable" and "family-friendly."

"We're not opposing density, we're just trying to shape it in a different way," says Steven Zettner, the group's co-founder and president. "We need to implement density in such a way that it will work for different kinds of people, and we will still have a strong sense of community."

Family Flight

The North Central neighborhoods were some of Austin's early suburbs, built roughly between 1945 and 1970. Inside their boundaries, away from major streets like Burnet and Koenig Lane, shaded streets and a grid system encourage walking. Many people say they moved to neighborhoods like Brentwood and Crestview specifically for the opportunity to walk and bike.

More families moved into the area between 2000 and 2010. But for SN's purposes, "we have to be careful about what time frame we're talking about," Zettner says. "If we're talking about the present or near future, it's a very popular family area and a lot of people are moving in. But as you change the mix of housing, you artificially limit the opportunities for families to move into the area. It starts to shift the retail mix. The demographics change over 10 or 15 years."

City demographer Ryan Robinson has compiled a top 10 list of Austin's demographic trends, which he occasionally features in presentations around town. No. 2 on his list is the declining percentage of families with children in central Austin. Between 1970 and 2000, the percentage of the population represented by this group shrank from 32% to just under 14%. Middle-class families in particular, Robinson writes in his analysis, are disappearing from the urban core.

"To me," Robinson said in an interview, "an urban core without families is not a success." He points to Portland – a city often emulated for its New Urbanist development that promotes density and alternative transportation. But Portland's income gap has grown in tandem with the new development. Robinson says that in the past 20 years, Portland city school enrollment has been cut in half, a change he attributes to the lack of affordable housing. "As Portland has built up and intensified and created mixed-use centers, they can be incredibly expensive to live in, and in many cases families get pushed out of the urban core. My opinion is that whenever there is competition for housing, families will lose, because there's more to pay for."

A shrinking population of children could lead to school closures in Austin as well as Portland, which closed a high school in 2011 and two other schools in 2012. While no Austin schools have been closed because of declining enrollment, the Austin Indepen­dent School District raised that prospect for several elementary schools and one middle school two years ago. Council Member Kathie Tovo, who at the time campaigned to keep the schools open, cites research from cities where central city schools have closed. "In many places the neighborhood school serves as a community convening place, and so when that school closes, you've got a big vacancy in the middle of the neighborhood. Property values go down. There's a kind of cohesiveness that's lost." The remaining families, who might previously have walked their kids to school, now have to drive – so there's an environmental impact, too.

Moreover, closing a school makes the neighborhood even less appealing to new families. "Once you close the school, you've pretty much written off that whole area as far as families with children go – so they're forced to go to the suburbs," Zettner says.

Family-Friendly or Anti-Fun?

Keeping schools open is part of SN's model of sustainability. So is keeping the neighborhoods workable for people in all stages of life. One word that comes up surprisingly often in this mostly white area of town is "diversity." Proponents say one thing that gives North Central Austin its character is the relatively diverse mix of ages, incomes, life stages, and businesses it supports.

"Sustainability is the capacity to endure," says Jonathan Locklin, a Crestview resident and SN board member. "If we just build for [the young, single] demographic, we won't have a whole community, and I'm afraid we'll lose the diversity which provides us perspective. Living amongst different groups of people that have different lifestyles and are in different stages of life is important. You have to know how the other person lives to respect and appreciate that person." To Locklin, Zettner, and others, "sustainability" has an environmental implication that's tied to a neighborhood's ability to accommodate diversity, including families. While not everyone on the board has a family, the group generally attracts parents who want to raise their kids in Central Austin.

Their goal is to offer as much of the suburbs' safety, affordability, and child-friendliness as possible in the urban core. "People may work Downtown or like an urban lifestyle but find raising kids Downtown is hard, so they're trying to find a middle zone that's not the suburbs at one extreme or Downtown at the other," Zettner explains. "They're willing to trade off having a huge house and a huge yard because they can use transit." The group thinks lots of families would make this trade-off if only it were more widely available. And if more families did so, the result would be less sprawl and less pollution from commuting.

While he only recently got interested in SN, Brentwood resident Sam Shore could be its poster child. Shore lives in a 1,064-square-foot house, built circa 1947, with his wife and three children. "For a lot less money, you could buy a big house in the suburbs, but then you have all the other problems of having to drive everywhere and deal with traffic," he says. "But if you could keep the schools good and manage to ride your bike or walk to them, that would be ideal. We'd like to stay here, and have our community be here in the heart of Austin."

The Shores bike and walk whenever they can, but it's not easy. Their street, like many in Austin, doesn't have sidewalks, and a new apartment building next door is expected to generate 1,200 additional car trips per day. The Shores live about a mile from Brentwood Elementary, but to get there on foot or bike they have to cross busy Koenig Lane, where the nearest traffic light requires a detour of several blocks. To reach Amy's Ice Creams, mere blocks away, the family has to negotiate a Burnet Road sidewalk so narrow that they duck to avoid the side mirrors of passing buses.

Sam Shore would like to see better sidewalks and bike lanes – components of what SN calls family-friendly development. Walk­ways wide enough for a little kid on a bike. Trees and shade to buffer the sidewalk from the street. Playscapes. Benches. "Some of the amenities that we tend to think of as attractors of families with children are sidewalks, great public spaces, and green spaces," says Council Member Tovo. "We associate them more with the needs of families with children, but those really benefit individuals across the life span."

"It's the lowest common denominator," Locklin explains. "If you build it child-friendly, it's going to be senior-friendly and disabled-friendly and adult-friendly."

Other aspects of family-friendliness are trickier to sell. SN, along with immediate neighbors, opposed the Little Woodrow's restaurant and bar proposed for the site of a former real estate office on Burnet. City Council recently approved changing the property's zoning to allow the bar. The neighbors objected to the bar's proximity to a residential neighborhood and its limited parking – concerns that will be addressed when Little Woodrow's goes before the Planning Commission in the conditional use phase of review. But comments on neighborhood listservs and websites suggested some people perceive the push for "family-friendly" as misplaced conservatism.

"There were some responses on the listserv saying 'you're anti-bar, you're against our ability to go have fun with other adults,'" says Locklin, who's 42 and doesn't have kids. "That's not what we want at all. We want to be able to service all the diversity that exists in the neighborhoods. We just don't want it to be a party place."

Room for Everybody?

The idea of Burnet Road turning into a "party place" comes from the rapid changes in development SN sees as courting young, childless singles – a group with different interests and spending habits than the families and seniors who live in the neighborhoods off Burnet now. Market pressure, SN contends, is leading developers to build primarily for young singles and empty nesters. The large apartment buildings and vertical mixed-use (VMU) projects sprouting along major streets offer residences that are too small and too expensive for the typical family with children. SN worries that over time, this influx of childless new residents may tip the balance of retail and restaurants away from places like Amy's Ice Creams and toward more bars like Little Woodrow's.

"My impression is that the city is very much in tune with the early-20s-and-single demographic because they drive a lot of economic activity by eating out, going to bars, and living in condos," says SN board member Brent Adair, an Allandale resident with 2- and 7-year-old children. "I'm a big fan of that demographic – I was that demographic – but if it receives too much focus, a lot of development might be geared toward that demographic to the exclusion of families with young children and seniors on a fixed income."

A more sustainable building pattern, the group says, would be inviting a variety of types of new housing that fit all demographics. "I would like to stay in [Crestview] through all my life stages, all the way to retirement and old age, so I would like that to be supported in the neighborhood," Locklin says. But how can a group like SN reach out to other people like Locklin? Zettner himself acknowledges that "if you're young and single and professional and in your twenties – at that age I could have cared less."

One argument for people who don't have kids is that, well, you might later on. "If you want to stay in the neighborhood, and you decide you want kids, and you want to move out of an apartment, where are you going to go?" Shore asks. "It's in everyone's interest to think about how you kind of 'age in place,' in a family sense as opposed to an elderly sense."

Another argument Tovo makes is economic. "The cities that tend to be the most economically stable have preserved a diverse mix of households in the central city, where you have a good mix of singles, older adults, families with children – a diverse population to support a diverse array of businesses."

Reception to SN's efforts is not universally positive. At February's Brentwood Neighborhood Association meeting, some residents pointed to the boom in enrollment at Brentwood Elementary as countering SN's concern about declining populations of children. The Allandale Neighbor recently ran essays with opposing views of "child-friendly" development along Burnet. Writing under the heading "Allandale is not Mayberry anymore," resident Linda Crim, 59, wrote that she disapproved of "special interest groups using words that emotionalize people and issues – words like family, child, bars and sustainability.

"There is a lot of talk about building 'child friendly,'" she continued. "I do not consider the new developments going up as not child friendly. The current run-down businesses, for instance the Poodle Dog Lounge, are the detriment. The new envisioned businesses are clean and modern and appeal to those who seek the amenities that they bring." Crim's essay reflects the view that market pressures make these sorts of changes inevitable.

Even Zettner sometimes worries that he comes across as overly apocalyptic in his vision of a low-child North Central Austin. "I worry that I sound like, 'Oh my God, it's going to be horrible,' and usually the reality is bigger than that," he says. "But I have heard people in the neighborhood say they never would have considered moving [away], and now they're questioning that."

Doing Density Right

Zettner, an Allandale resident and father of three young children, is not an urban planner by trade. The idea for SN emerged after his involvement with the VMU opt-out process the North Central neighborhoods went through in 2007. Finding the process confusing and frustrating to non-urban planners, he thought it would be good for the residents to more proactively define what they want for the area. Around that time he tried to take his first child to a restaurant in a stroller, and the process of walking along Burnet and trying to cross it was so harrowing that he decided something had to change.

SN members insist that they're not opposed to development or new residents. They just want these things to be done in a way that accommodates the existing neighborhoods. "I feel like a lot of central neighborhoods get categorically dismissed as 'not in my backyard' and opposing density at all turns," Adair says. "So us getting out the message of how we believe density ought to be done, that would be a great start."

Here's how they say density ought to be done.

Step 1: Concentrate it in "village centers" near anticipated transit stops, like the Bus Rapid Transit that's coming to Burnet Road later this year. Include retail, services – day care, perhaps – and open space like a pocket park. (Imagine a more affordable Triangle, located on a major transit stop and including a grocery store.) The strategy presumes people will be more likely to use mass transit if it's close to their home and the stop is a comfortable place to wait – it's shaded, it's buffered from the street by trees, maybe there's a park or food nearby. SN fears that adding all the density that's currently planned for Burnet without supporting it with pocket parks, transit, and wide sidewalks will just dump more cars onto the already congested road.

Step 2: Farther from the village center, in the "transition zone," build lower-density, more affordable housing like row houses, fourplexes, and townhomes. These will have small private yards along with larger shared green space. These smaller buildings will create a buffer between really dense development along major roads and the quieter, single-family-home neighborhoods they border. Aside from a few row houses in the Mueller neighborhood, you won't see much of this type of development in Austin.

"One of the struggles we had on the Families and Children Task Force was how to encourage the development community, when they're building multifamily housing, to really think about and prioritize the needs of families and children," Tovo said. "To make sure there's first-floor storage spaces for strollers or bicycles, to have a mix of outdoor space that might be private as well as good community spaces, to build smaller units with more bedrooms. What we heard back from the developers we talked to is that lenders tend to be pretty conservative, and that's a little bit of an untested model in this part of the country."

The upcoming rewrite of the land development code may provide opportunities to incentivize this type of housing. One yet-untried idea from the Families and Children Task Force is a partnership between the city and a developer to build a pilot project on city-owned land. "The city could model well-designed, family-friendly, multifamily housing as a way of educating the development community about design strategies – in effect testing that model in this market," Tovo says.

Looking for New Tools

By the time that happens, Burnet Road itself will be largely redeveloped. Without an explicit, overarching strategy to accommodate density, the neighborhood can anticipate a series of smaller battles – one bar, traffic light, or narrow sidewalk at a time.

Zettner has an MBA, and he remembers learning about the concept of comparative advantage – the idea that businesses should "find their niche": the thing they do better than any similar competitor. He applies the same theory to Burnet Road, which SN is branding "Austin's kid-friendly corridor."

"Doesn't it represent a risk for the city if we're creating the same environment everywhere?" he asks. "The same kind of mixed-use, trendy, hip restaurants and bars for the same demographic? What's going to happen in 10 to 15 years when they've all aged and some are single but some are raising families? San Francisco attracted that demographic 20 years before us, and when families emerge they have to move to the suburbs or across the Bay. Are we going to end up in that boat because we're obsessively building one thing in the urban core?"

If SN has its way, Burnet and areas like it will work to keep their age-diverse character even as newcomers arrive. "The biggest risk we face is that the city will continue to apply the same kinds of tools that they've developed elsewhere, but that fit poorly in early suburbs," Zettner wrote on the Crest­view neighborhood listserv in February. "If we're going to reinvent Burnet, why not shape a child-friendly environment that takes advantage of the strengths we already have?"

Households With Children

2010 Census Total Pop. Total Households % Age 17 and Under Allandale 6,643 3,263 18.6% Brentwood 7,513 4,127 12.6 Crestview 3,927 1,945 14.7 Highland 4,225 1,910 16.7 North Shoal Creek 3,471 1,948 13.4 Wooten 5,339 2,027 24.8 2000 Census Total Pop. Total Households % Age 17 and Under Allandale 6,411 3,157 17.5% Brentwood 8,041 4,173 14.0 Crestview 3,968 1,851 16.1 Highland 4,526 2,024 17.6 North Shoal Creek 3,936 2,093 13.7 Wooten 5,590 2,195 23.2

Source: 2010 and 2000 Census, and American Community Survey Data