Emergence of Ixodes scapularis (Acari: Ixodidae) in a Small Mammal Population in a Coastal Oak-Pine Forest, Maine, USA.

In the United States, surveillance has been key to tracking spatiotemporal emergence of blacklegged ticks [Ixodes scapularis Say (Ixodida:Ixodidae)] and their pathogens such as Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner (Spirochaetales: Spirochaetaceae), the agent of Lyme disease. On the Holt Research Forest in midcoastal Maine, collection of feeding ticks from live-trapped small mammal hosts allowed us to track the emergence and establishment of I. scapularis, 1989-2019. From 1989-1995, we collected only I. angustus Neumann (Ixodida: Ixodidae)(vole tick), Dermacentor variabilis Say (Ixodida: Ixodidae) (American dog tick), and I. marxi Banks (Ixodida: Ixodidae) (squirrel tick) from seven species of small mammals. The most abundant tick host was the white-footed mouse [Peromyscus leucopus Rafinesque (Rodentia:Cricetidae)] followed by the red-backed vole (Myodes gapperi Vigors (Rodentia: Cricetidae)). Emergence of I. scapularis was signaled via the appearance of subadult I. scapularis in 1996. Emergence of B. burgdorferi was signaled through its appearance in I. scapularis feeding on mice in 2005. There was a substantial increase in I. scapularis prevalence (proportion of hosts parasitized) and burdens (ticks/host) on white-footed mice and red-backed voles in 2007. The ~11-yr time-to-establishment for I. scapularis was consistent with that seen in other studies. White-footed mice comprised 65.9% of all captures and hosted 94.1% of the total I. scapularis burden. The white-footed mouse population fluctuated interannually, but did not trend up as did I. scapularis prevalence and burdens. There were concurrent declines in I. angustus and D. variabilis. We discuss these results in the broader context of regional I. scapularis range expansion.

Long-term effects of group-selection timber harvesting on abundance of forest birds.

Relatively few studies have examined the ecological effects of group-selection timber harvesting, and nearly all have been short-term and have lacked experimental manipulations that allow pre- and posttreatment comparisons. We have been documenting the effects of a group-selection timber harvest on bird abundance in a Maine forest for 24 years (preharvest, 1983-1987; postharvest, 1988-2006). Here we characterized the trends in bird abundance over the first 20 years of the study in the managed and control halves of the 40-ha study area. Species responses to the group-selection harvest were idiosyncratic, but in general the mature-forest bird community was retained and species dependent on early successional habitat temporarily (