Other natural or manmade factors affecting its continued existence. Impacts from Drought Drought is considered a universal ecological driver across the Great Plains (Xxxxx 1996). Infrequent, severe drought may cause local extinctions of annual forbs and grasses that have invaded stands of perennial species and recolonization of these areas may be slow (Tilman and El Haddi 1992). In this way, drought may impact LPC through its effect on seasonal growth of vegetation necessary to provide nesting and roosting cover, food, and opportunity for escape from predators (Xxxxxxxx 1982; Xxxxxxxx and Xxxxx 1994; Xxxxxx et al. 1996). The sensitivity of LPC to drought was discussed by Xxxxxxxx (1980) and Xxxxxxxxxx and Xxxxxxxxxx (1961). Precipitation appears to affect LPC adult population trends with a potential lag effect (Xxxxxx 2000). That is, rain in one year promotes more vegetative cover for eggs and chicks in the following year, which enhances their survival. The effects of drought are likely exacerbated by land use practices, but no studies have clearly demonstrated such cumulative impacts on populations (Xxxxx and Xxxxxx 2005). Along with other prairie grouse, LPC have a high reproductive potential in years of adequate conditions. In New Mexico, southern portions of the species range, which on average receive less total precipitation (i.e., Carlsbad area), are impacted more frequently and more severely by drought. LPC populations in these areas may have always been smaller and more variable than those farther to the north, although population data are insufficient to say this with certainty. Thus, drought conditions are unlikely to be the sole causative factor in long-term LPC population declines. The effects of drought on population growth rate may be more significant in small, fragmented populations. Impacts from Collision Mortality Wire fencing is common throughout LPC range as a means of confining livestock to ranches and pastures, or excluding them from areas not intended for grazing such as CRP, agricultural fields, and public roads. Like most grassland wildlife, LPC evolved in open habitats free of vertical features or flight barriers. Fences, power lines, or other wire structures are an unnatural threat to prairie grouse that, until recently, were seldom perceived as significant at the population level (Xxxxx et al. 2007). From 1999 to 2004, researchers recovered 322 carcasses of radio marked LPC in New Mexico, Oklahoma, and portions of the Texas panhandle. In New Mexico, only 14 percent of mortality could be traced to...
Other natural or manmade factors affecting its continued existence. The species is an extreme habitat specialist associated with a single plant species that exists in an ecosystem that was previously more widespread and is now relict. Factors such as short life span, small clutch size, and the presence of natural competitors and predators contribute to the precarious status of this species. The species occurs in a fragmented range where populations are not connected for genetic exchange and are vulnerable to genetic drift and population loss due to random events. Because the species is not known to cross large expanses of unsuitable habitat, there is little chance of suitable habitat being recolonized without human intervention. Additionally, many natural events can quickly impact the shinnery oak system that would be equal to spraying with an herbicide or mechanically removing vegetation. Sudden Oak Death, drought, freezes, infestation of root boring insects, and a known lepidopteran parasite can quickly defoliate and kill giant stands of shinnery oak (Xxxxxxxx and Xxxx 1998). Impacts from Exposure to Toxic Chemicals and Hydrogen Sulfide (H2S) Emissions Oil fields can contain a variety of activities that release toxic pollutants including petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAH) (e.g., phenanthrene, fluoranthene, and benzo[a]anthracene), oil spills, and air pollutants (U.S. Environmental Protection Agency 1999). Xxxxxxx et al. (2008) reported that tissue samples taken from a sand dwelling lizard in Kuwait and its insect prey base (ants) contained PAH concentrations that increased with increasing exposure to these pollutants. Xxxxxxx et al. (2008) reported that the concentrations of PAHs in lizard and ant tissues could impact the function of vital organs. Lizards may not be able to remove these chemicals from their system quickly due to their slow metabolic rate and simple enzyme system (Xx-Xxxxxx et al. 2007). The exposure to oil field chemicals also impacts the behavior and foraging time for sand lizard species (Xxxxxxx et al. 2008). The sand dwelling lizard in Kuwait is of similar size and resides in similar habitat to SDL. Because much of SDL’s habitat is located in small dune patches within oil and gas fields, the potential for exposure to toxic pollutants including both oil spills and chemical leaks is high. Xxxx and Xxxxx (1997) found that the number of SDLs decline with the increase in number of well pads per section. This could be due to the destruction of the shinnery oak habitat and the pre...
Other natural or manmade factors affecting its continued existence. Stochastic Events The large aegialian scarab’s and Xxxxxxxx’x dune scarab’s ranges are limited to Big Dune and Lava Dune; the Crescent Dunes aegialian scarab’s range is limited to Crescent Dunes and San Antonio Dunes; and Crescent Dunes serican scarab’s range is limited to Crescent Dunes. Extreme environmental disasters at these areas, such as earthquakes, hurricanes, tornadoes, severe floods, or severe and frequent winter storms, could impact these species through direct mortality or removal of vegetation. However, this area has one of the lowest frequencies of extreme environmental disasters in the United States (DOE 1986, pp. 3–22, 6–27, 6–32), and any extreme weather phenomena occurring in the desert are of such short duration that no significant effects are expected (DOE 1986, pp. 6–27, 6–32). We do not consider extreme environmental disasters a threat to these four beetle species. Climate Change Our analyses under the Act include consideration of ongoing and projected changes in climate. The terms ‘‘climate’’ and ‘‘climate change’’ are defined by the Intergovernmental Panel on Climate Change (IPCC). The term ‘‘climate’’ refers to the mean and variability of different types of weather conditions over time, with 30 years being a typical period for such measurements, although shorter or longer periods also may be used (IPCC 2007a, p. 78). The term ‘‘climate change’’ thus refers to a change in the mean or variability of one or more measures of climate (e.g., temperature or precipitation) that persists for an extended period, typically decades or longer, whether the change is due to natural variability, human activity, or both (IPCC 2007a, p. 78).
Other natural or manmade factors affecting its continued existence. Climate Change
Other natural or manmade factors affecting its continued existence. The species is an extreme habitat specialist associated with a single plant species that exists in an ecosystem that was previously more widespread and is now relict. Factors such as short life span, small clutch size, and the presence of natural competitors and predators contribute to the precarious status of this species. The species occurs in a fragmented range where populations are not connected for genetic exchange and are vulnerable to genetic drift and population loss due to random events. Because the species is not known to cross large expanses of unsuitable habitat, there is little chance of suitable habitat being recolonized without human intervention. Additionally, many natural events can quickly impact the shinnery oak system that would be equal to spraying with an herbicide or mechanically removing vegetation. Sudden Oak Death, drought, freezes, infestation of root boring insects, and a known lepidopteran parasite can quickly defoliate and kill giant stands of shinnery oak (Xxxxxxxx and Xxxx 1998).
