Publications

@article{Sabo2003,

title = {Hot rocks or no hot rocks: overnight retreat availability and selection by a diurnal lizard},

author = {John L. Sabo},

url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Hot-Rocks-or-No-Hot-Rocks-Overnight-Retreat-Availability-and-Selection-by-a-Diurnal-Lizard_Sabo_2003.pdf},

doi = {10. 1007/s00442-003-1292-6},

year  = {2003},

date = {2003-08-00},

journal = {Oecologia},

volume = {136},

number = {3},

pages = {329-335},

abstract = {I used radio telemetry to determine the effects of substrate size and composition on overnight retreat site selection by western fence lizards (Sceloporus occidentalis). In watersheds of northern California (USA), these lizards occupy two habitat types differing in substrate characteristics: rocky cobble bars found in the dry, active channels of rivers and grassy upland meadows. Rocky substrates, found almost exclusively on cobble bars, provided warmer potential retreat sites than all available retreat sites on meadows during the first 5 h of inactivity. Only cobble and sand substrates provided retreats with temperatures within the preferred daily active range (32-36°C) during the inactive period for these lizards (1900-0900 hours). Females on a cobble bar used rocks as retreats on >90% of nights during the breeding season whereas females on a meadow used wood (>70% of nights) and burrows (>25% of nights). In contrast to females, cobble bar males used rocks significantly less frequently (<70%) and slept in the open air significantly more frequently (25% vs. <1%). Cobble bar females further, showed a significant preference for cobbles 15 cm thick, whereas the rocks used by males did not differ significantly in thickness from those measured in randomly placed transects. Rocks 15 cm thick were the warmest retreats commonly available on this habitat type. Thus, thermal microenvironments available to and chosen by gravid female lizards differ considerably between river and non-river habitats.},

keywords = {Habitat selection, Retreat site, Riparian, Sceloporus occidentalis, Thermoregulation},

pubstate = {published},

tppubtype = {article}

}

@article{Sabo2002e,

title = {Numerical response of riparian lizards to aquatic insects and the short-term consequences for alternate terrestrial prey},

author = {John L. Sabo and Mary E. Power},

url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Numerical-response-of-riparian-lizards-to-aquatic-insects-and-the-short-term-consequences-for-alternate-terrestrial-prey_Sabo_2002.pdf},

doi = {10.2307/3071839},

year  = {2002},

date = {2002-00-00},

journal = {Ecology},

volume = {83},

number = {11},

pages = {3023-3036},

abstract = {Spatial subsidies, or inputs of resources from more productive donor habitats, can cause numerical responses in consumer populations via behavioral and demographic mechanisms. In addition, subsidies may have indirect effects on the in situ prey of these consumers. These indirect effects can be either negative (e.g., apparent competition) or positive (e.g., via diet shifts) depending on the relative strength of the predator’s functional and numerical responses to prey subsidies. Here we report a numerical response by a lizard (Western fence lizard, Sceloporus occidentalis) to experimental reductions in the flux of river-derived insects. Initially, equal densities of lizards declined significantly faster in plots in which aquatic insect abundance was reduced by nearly 50% (season average) relative to controls. Abundance and biomass of terrestrial arthropods declined significantly between the start and end of the experiment across treatments. Despite consistently lower lizard abundance in plots with reduced subsidy levels, however, relative declines in the abundance and biomass of in situ terrestrial arthropods (all taxa combined) were not significantly different between reduced- and ambient-subsidy plots. Relative declines in spider biomass differed significantly between treatments and were higher in reduced-subsidy than ambient-subsidy plots, but only over one of three 3-wk sampling intervals. Thus, over the biologically active summer season, aquatic subsidies exerted brief positive or no significant indirect effects on the in situ prey of riparian lizards. These results suggest that, although aquatic insect prey may determine the spatial distribution and local abundance of riparian predators, the effects of increased predator density on in situ prey may be offset by higher per capita predation by these consumers on in situ prey in subsidy-poor relative to subsidy-rich habitats. 

Numerical response of lizards to aquatic insects and short-term consequences for terrestrial prey.},

keywords = {Carabidae, food web, indirect effects, insect, lizard, Lycosidae, numerical response, Riparian, river–watershed exchange, Sceloporus occidentalis, subsidy, Western fence lizard},

pubstate = {published},

tppubtype = {article}

}