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400 A COMPrEHEnSIvE GUIDE TO SOlAr EnErGy SySTEMS

imperial eagle (Aquila adalberti; [49]), Bonelli’s eagle (Aquila fasciata; [50]), and the Eur-
asian eagle owl (Bubo bubo; [51]). Guidelines for reducing electrocution risks, such as mini-
mum conductor spacing, may help mitigate some avian mortality [52]. lastly, steel towers
and power poles provide hunting perches for opportunistic predatory birds, which may
increase predation risk for slow or sedentary wildlife (e.g., ravens predating desert tortoise;
[11]). These effects are not unique to USSE and no studies to date have studied ecological
impacts from transmission lines specifically associated with solar energy power plants.
In addition to fragmenting habitat, fence lines surrounding USSE developments for
security may act as dispersal barriers to some species of wildlife. Bats and most birds can
fly over fences, with a few exceptions (e.g., roadrunners), and insects and small bodied
animals (e.g., lizards, snakes, and rodents) may travel unimpeded through some fences.
However, larger bodied animals (e.g., kangaroo rats—Dipodomys spp.) and animals with
small home ranges (e.g., desert tortoises) may be excluded. This may prevent gene flow
between individuals located on either side of the fence line. Promisingly, fences may be
engineered to accommodate the needs of some species (e.g., kit foxes in the San Joaquin
valley of California, United States; [53]).

20.3.3 Panels and Mirrors
large expanses of Pv panels and mirrors may be perceived by flying species as flat-water
bodies [54]. This phenomenon, known as “the lake effect”, occurs when flying species
mistake flat surfaces of mirrors and modules for water. Some species may suffer impact
trauma from collision as they attempt to land whereas others (e.g., waterfowl) may strand
themselves because they are unable to easily take off from a terrestrial surface. Both sce-
narios increase risk of mortality or injury leading to starvation or predation [55]. non-fatal
collisions of large-bodied birds with panels were documented at Pv facilities in South Africa
[29] and southern California [55], and impact trauma was the leading cause of avian death
documented at a Pv and parabolic trough facility in the Mojave Desert, United States [55].
Additionally, the presence of ponds at Pv facilities may serve as an attractant to waterbirds
and flocking birds [29,55]. no positive effects of panels or mirrors are documented for
waterbirds or flocking birds. Polarized light from Pv panels and mirrors can attract insects
[56], which, in turn, may attract insectivorous raptors (e.g., kestrels—Falco spp.) and insect
gleaning bats that might utilize Pv fields and evaporation ponds for foraging [29]. Sub-
adult bats have been observed attempting to drink off of panels [57], suggesting that they
are attracted to and confused by the panels; it is not known if these wasted attempts cause
detrimental energy expenditures. If vegetation is allowed to regrow between panels, ter-
restrial foraging birds may utilize those areas for shade and shelter. Birds may also utilize
the underside of panels or the ground beneath panels as nesting sites [29]. nesting success
may depend upon the presence of predators within the facility footprint. Small carnivores
(e.g., kit fox, Vulpes macrotis) may be able to establish natal dens within Pv arrays [58].
Pv panels and mirrors may have a negative impact on both annual and perennial
native plant species, which are well adapted to their local, unshaded environments. For