Interactions among rainfall, fire, forbs and non-native grasses predict occupancy dynamics for the endangered Pacific pocket mouse (Perognathus longimembris pacificus) in a Mediterranean-type ecosystem

Fecal metabarcoding of the endangered Pacific pocket mouse (Perognathus longimembris pacificus) reveals a diverse and forb rich diet that reflects local habitat availability

“…However, we still detected some differences in above‐ground seed availability and proportion in fecal samples that indicate diet preferences for some forbs, perennial herbs, and native bunch grasses over perennial shrubs and non‐native grasses. These results, along with the complimentary results of a concurrent occupancy study (Brehme et al, In Review), described in more detail below, can help us to better understand relationships between food resources and the population dynamics of PPM. Our results also provide information about specific forbs and perennial herbs that can be incorporated into habitat restoration and site selection and preparation efforts for establishing new populations (Chock et al, 2022).…”

“…Conversely, higher non‐native grass cover has been a primary predictor of decreased probability of PPM occupancy and increased probability of localized extinction across sites (Brehme et al, In Review). Large contiguous stands of annual grasses impede the growth of other plant species (Flory & Clay, 2010) and may hinder PPM movement and foraging success.…”

“…PPM is primarily found in open habitat with coastal scrub, grasses and forbs, and loose sandy soils (USFWS, 2020). Like other heteromyids, food availability appears to be a limiting factor linked to PPM activity patterns, behavior, and reproduction (Bartholomew & Cade, 1957; Brehme et al, In Review; Meserve, 1976). For example, PPM enter facultative torpor during the winter and in response to low resource conditions, and their above‐ground active season coincides with high annual forb availability (Brehme et al, In Review; Shier, 2008).…”

“…Like other heteromyids, food availability appears to be a limiting factor linked to PPM activity patterns, behavior, and reproduction (Bartholomew & Cade, 1957; Brehme et al, In Review; Meserve, 1976). For example, PPM enter facultative torpor during the winter and in response to low resource conditions, and their above‐ground active season coincides with high annual forb availability (Brehme et al, In Review; Shier, 2008). Reproduction also fluctuates in response to available resources; there may be no reproduction in low‐resource years (Brehme et al, 2020).…”