While I’ve been busy shirking my blogging duties over the past year, many people have been busy keeping Portal up and running. After we ran out of NSF funding last summer to fund research collection at the site, we were able to keep collecting data bi-monthly for the rest of 2010 on a shoestring budget and with a lot of help from Portal volunteers past and present. Luckily for us, rodent numbers remained extremely low throughout 2010 so maintaining rodent exclosures was not problematic, even with the decrease in trapping frequency. In addition, we were able to secure some funding for the next two years and began trapping each month again in January 2011. There is not a lot of money for incidentals, so we are continuing to use a combination of pit-tags and ear tags for individual markers until they run out and are keeping our fingers crossed that the trap shed and other necessary supplies can last a few more years.
Trapping this year has been interesting–dealing with record cold temperatures, smoke from the Horseshoe 2 forest fire in Cave Creek Canyon, and a very pesky pack rat that seems intent on living in our trap shed and destroying as many trap box shoulder straps as possible. The spring and winter were extremely dry, combined with record-low temperatures in February, and there was almost no spring germination. Consequently, this past winter, rodent numbers once again dropped extremely low (20-30 rodents in the entire site!), but enough survived the last year to reproduce this spring and our numbers this summer have been >100 rodents on site. This is still a very small number compared to more productive summers only a few years ago and we have also seen a drastic change in species diversity at the site compared to a few years ago. We are currently capturing only 4 species–Merriam’s kangaroo rat (Dipodomys merriami; common), Ords kangaroo rat (Dipodomys ordii; rare), desert pocket mouse (Chaetodipus penicillatus; very common), Bailey’s pocket mouse (Chaetodipus baileyi; very rare), and southern grasshopper mouse (Onychomys torridus; common). In 2011, it seems like we are drowning in desert pocket mice (Chaetodipus penicillatus). In fact, there are plots where kangaroo rats (Dipodomys spp.) should be “king” and instead, we are ONLY catching desert pocket mice! Its all very surprising, but perhaps that is what makes Portal so interesting.
The Portal Project 