How urban gardens improve biodiversity

Growing fruit and vegetables, it turns out, isn't always good for the ecosystem, especially if only one product is being grown over a large area.

AUSTIN (KXAN) — Growing fruit and vegetables, it turns out, isn't always good for the ecosystem, especially if only one product is being grown over a large area. But if a garden is diverse, like urban gardens typically are, an ecosystem can thrive.

Meteorologist Nick Bannin spoke with Dr. Shalene Jha from the University of Texas at Austin and the Lady Bird Johnson Wildflower Center about a new study Jha collaborated on that looked at the impacts of an urban garden. This is a part of that discussion.

Meteorologist Nick Bannin: Dr. Jha, some people think that food cultivation is bad for biodiversity and an ecosystem, but your recent study found differently, right? Can you explain?

Dr. Shalene Jha, associate professor of integrative biology at UT Austin: Sure. So this classical concept that food and biodiversity don't get along, comes from, you know, these large-scale monoculture cultivation practices, which are often in rural areas. But what we find with urban gardening, is actually they're extremely species-rich — so lots of plant diversity in a small area. And that really allows us to support a lot of animal biodiversity as well as food production.

Bannin: What is an urban garden?

Jha: An Urban Garden is any gardening space in an urban area that people use for food production. So it could be for herbs or vegetables or fruits; they vary in size. And so yeah, some can be, you know, the size of somebody's backyard, or you know, even a small porch garden counts as an urban garden. But what we're finding is that even if the garden is very small, it can have pretty major impacts in terms of supporting local biodiversity as well as producing food.

Bannin: How much food do we get from urban gardens versus the more traditional, bigger farm?

Jha: So that's one of the reasons that we decided to pursue this study, actually. Urban gardening is contributing to larger and larger portions of the global food supply. So right now, it's estimated that about 15-20% of the global food supply comes from urban gardens, and that proportion is just increasing.

What we're finding in urban garden systems, especially the ones we studied, is that they're producing incredible quantities of food, very nutritious food for the gardeners, but at the same time, they're also supporting a lot of ecosystem services, so things like climate buffering, and carbon sequestration and also human well-being. So the gardener is cultivating food, but they're also experiencing a greater sense of connectedness and security. So it's a win-win. In these urban gardens, we're producing food, but also supporting local biodiversity and other ecosystem services like human well-being.