Ocelot_Diversity_Young_John_AustinTX_8December2023_Reel4182.mp3

John Young [00:00:00] Somebody at one time at the Laguna Atascosa documented this term called, "frustrated dispersal".

John Young [00:00:07] And so, imagine you're a young cat and you decide, "Okay, I'm going to head out, try to find my own place", and you take off across the countryside. And you can't find a suitable area. You can't find a mate.

John Young [00:00:21] So, what do you do? You turn around and go back home.

John Young [00:00:26] And yet, there's really nothing for you there either. Unless you can, as a male cat, would have to knock another male cat out of the territory.

John Young [00:00:36] So, that was kind of what was happening with the Laguna populations, is that they would take off and then eventually come back if they weren't hit on the road. And that was one of the major sources of mortality for ocelot - road mortality.

John Young [00:00:52] And TXDOT, Parks and Wildlife Department, Fish and Wildlife Service all started to try to address that in the early to mid-'90s with developing wildlife crossings for ocelot...

John Young [00:01:07] TXDOT has provided, I think we're up around 30 ocelot crossings now on various roads that are both adjacent to known populations, but also lie on potential routes of dispersal that the Fish and Wildlife Service has recognized.

John Young [00:01:26] And, can we get wildlife crosses on State Highway 100? Those are meant to help dispersing ocelots get into the Bahia Grande Wetland Complex.

John Young [00:01:38] Crossings being built on U.S. 77: those are aimed at helping the ocelot get from the east side of U.S. 77 to the west side of U.S. 77.

John Young [00:01:49] And so the road crossings are really instrumental in helping these animals to get across the road successfully. And we've had success. We've had success with ocelots using wildlife crossings that we've put out...

John Young [00:02:03] When I first started looking at wildlife crossings for ocelots and started doing research, I thought there'd be one key item, right? There's going to be that magic box culvert size, right? It's going to be an eight by ten, or a ten by ten, or it's going to be a bridge.

John Young [00:02:21] And the more research that I've done, and the more that we've looked into this, it looks more and more like there isn't going to be one magic size. It's not a bridge. It's not just a box culvert. There's a whole range of different size structures...

John Young [00:02:39] When we look at State Highway 100, we have box culverts there that are ten-by-ten and have running water under them. So, we put a concrete step in. And we have box culverts that are three-by-four, and that's three foot tall and four foot wide. So, very small, right?

John Young [00:02:56] And we documented a mountain line going through the smallest culvert on State Highway 4...

John Young [00:03:03] So, in a way, that is a good thing, right, because the diversity of size culverts and different crossing structures that we can provide means that I have more options to work with that engineer. If an engineer tells me, "Hey, we can only get a three-by-three culvert in here", that is still potentially suitable as a wildlife crossing.

John Young [00:03:26] It may not be as useful a crossing as something that every animal can go through, like a bridge, right? A bridge crossing: deer, turkey, ocelot - they can all go through that. A three-by-three culvert? You're probably only going to get ocelots, bobcats, raccoons and possums and a host of other small species.

John Young [00:03:48] But, we have documented in our work upwards of 24 different species using the culverts on State Highway 100 and F.M. 46. We've documented 20 to 30 to 40,000 animals going under and through those crossings...

John Young [00:04:05] Our roadkill information says that we have seen some reductions in the amount of animals that get killed. We've also seen some shifts in where road mortality occurs, right?

John Young [00:04:18] But overall, if you look at the fact that we're passing 20 to 30,000 animals and say 25, 30% of those would have wound up dead on the highway, yeah, we're having a significant impact on the movement and the survivability of different species.