Before you start reading this post, you might want to start at the post entitled “Wildlife Use of Native Perennial and Exotic Annual Grasslands: A Comparative Study” (https://kristinamwolf.com/2014/01/31/wildlife-use-of-native-perennial-and-exotic-annual-grasslands-a-comparative-study/). That will explain from the beginning the study design and what we have been doing with this ever-growing multi-trophic, multi-season, multi-scale research investigating wildlife habitat use of restored native perennial grasslands as compared to unrestored exotic annual grasslands (the “control”). If you have any questions, please feel free to contact me at kmwolf[AT]ucdavis.edu (replace [AT] with the @ symbol). Thanks!!
Hello again! This post is a follow-up to my previous wildlife posts, giving more details about my July wildlife sampling.
NEW THIS TIME: Raptor surveys and fire ant infestation trials!
Well here it goes again – take two. Only now instead of worrying about cold weather and rain, we had to contend with 113 degree (F) weather and making sure the rodents did not suffer from heat exposure in the traps. To that end, I was out of bed at 3:30 AM every single day for over 30 days, and didn’t return home until about 10 PM each night. It was a rough July… I heard there was a holiday in there somewhere, but I didn’t notice!
Per the usual, we ran into some difficulties along the way. For the first time, we discovered that wild pigs (Sus scrofa) are present at one of the four sampling locations. Pigs are 1) really curious; 2) really strong; and 3) really hungry. That’s a powerful combination, and makes live traps full of peanut butter and oats an overpowering attractant. Unfortunately, about 30 live traps were damaged, but luckily the game cameras were surprisingly resilient to pig inspections, although the bait blocks did not survive. Next time we will have to think carefully about how to reduce visitation to the sampling sites by these large non-native bulldozers.
We captured 760 rodents (468 unique individuals) across all locations, and rodents were captured in higher numbers at the control (unrestored) sites than at the restored sites across all locations that were fully sampled. We will not use the data from the Zamora site because a large herd of 130 sheep were put into the sampling site on the first day of trapping, and their very presence appears to strongly alter rodent capture rates (i.e., rodent behavior). However, the other three locations still had usable data, and patterns were consistent with the first season (April) of wildlife sampling.
Sadly, coverboards were hardly utilized over the summer – but who can blame the rodents and herps: it was HOT! That said, even with low abundance of rodents under coverboards, the pattern of higher use at control sites remained consistent in the summer.
Raptor surveys started in July, headed up by U.C. Davis undergraduate student Ryan Bourbour – a skilled and highly motivated birder with tons of training and experience with raptors. He took some amazing photos at the Elk Grove sampling location:
Raptor activity was higher as well at control (unrestored) sites as compared to restored sites. Looks like there may be some positive relationships here between rodent, snake, and raptor use of these two habitats!
We also noticed that fire ants seemed to be infesting Sherman live traps at a higher rate in control (unrestored) sites, so we started monitoring those to see if that was the case, and to also see if fire ants were influencing trapping rate at either of the sites. A few mice were injured by fire ants, and at least one was killed by fire ants. Fire ant data was collected at two locations for a subset of days.
Stay tuned for next time we sample in the fall!
Featured Image: Ryan Bourbour, U.C. Davis