The ranges of plants and animals are moving in response to recent changes in climate. As temperatures rise, ecosystems with ?nowhere to go?, such as mountains, are considered to be more
threatened. However, species survival may depend as much on keeping pace with moving climates as the climate?s ultimate persistence4,5. Here we present a new index of the velocity of temperature change (km yr21), derived from spatial gradients (6C km21)
and multimodel ensemble forecasts of rates of temperature increase (6Cyr21) in the twenty-first century. This index represents the instantaneous local velocity along Earth?s surface needed to maintain constant temperatures, and has a global mean of
0.42kmyr21 (A1B emission scenario). Owing to topographic effects, the velocity of temperature change is lowest inmountainous biomes such as tropical and subtropical coniferous forests
(0.08 kmyr21), temperate coniferous forest, and montane grasslands. Velocities are highest in flooded grasslands (1.26kmyr21), mangroves and deserts. High velocities suggest that the climates of only 8% of global protected areas have residence times exceeding 100 years. Small protected areas exacerbate the problem in Mediterranean-type and temperate coniferous forest biomes. Large protected areas may mitigate the problem in desert biomes. These results indicate management strategies for minimizing biodiversity loss from climate change. Montane landscapes may effectively shelter many species into the next century. Elsewhere, reduced emissions, a much expanded network of protected areas, or efforts to increase species movement may be necessary.
The impact of human land uses on ecological systems typically differ relative to how extensively natural conditions are modified. Exurban development is intermediate-intensity residential development that often occurs in natural landscapes. Most species-habitat models do not evaluate the effects of such intermediate levels of human development and even fewer predict how future development patterns might affect the amount and configuration of habitat. We addressed these deficiencies by interfacing a habitat model with a spatially-explicit housing-density model to study the effect of human land uses on the habitat of pumas (Puma concolor) in southern California. We studied the response of pumas to natural and anthropogenic features within their home ranges and how mortality risk varied across a gradient of human development. We also used our housing-density model to estimate past and future housing densities and model the distribution of puma habitat in 1970, 2000, and 2030. The natural landscape for pumas in our study area consisted of riparian areas, oak woodlands, and open, conifer forests embedded in a chaparral matrix. Pumas rarely incorporated suburban or urban development into their home ranges, which is consistent with the hypothesis that the behavioral decisions of individuals can be collectively manifested as population-limiting factors at broader spatial scales. Pumas incorporated rural and exurban development into their home ranges, apparently perceiving these areas as modified, rather than non-habitat. Overall, pumas used exurban areas less than expected and showed a neutral response to rural areas. However, individual pumas that selected for or showed a neutral response to exurban areas had a higher risk of mortality than pumas that selected against exurban habitat. Exurban areas are likely hotspots for pumahuman conflict in southern California. Approximately 10% of our study area will transform from exurban, rural, or undeveloped areas to suburban or urban by 2030, and 35% of suitable puma habitat on private land in 1970 will have been lost by 2030. These land-use changes will further isolate puma populations in southern California, but the ability to visualize these changes had provided a new tool for developing proactive conservation solutions.
Human intrusion, the mere presence of people in the environment, has become a dominant form of disturbance in many landscapes. Some forms of intrusion from recreationists and other groups occur repeatedly and can seriously alter avian reproduction, survival, and habitat use. Accordingly, repeated intrusion has the potential to cause impacts that accumulate through time and that are manifested as progressive declines in avian richness and abundance. From 1989 to 1993, we experimentally assessed whether or not temporally cumulative impacts occurred in Wyoming bird communities as a result of re- peated intrusion by solitary hikers; the intrusions lasted 1-2 h each week during 10 consecutive weeks of each year's breeding season. We tested a priori hypotheses about declines in overall richness and abundance, relative richness and abundance for sets of common and uncommon species, richness and abundance for six guilds, and separate abundances of four common species. Relative richness and abundance for the set of common species were the only metrics to exhibit significant declines between years during the 5-yr period. The declines in these variables, however, were not cumulative. At a statistical power level of 0.85, minimum detectable differences for many variables were small enough to have allowed easy detection of substantive declines, had any occurred. The yearly effects we detected for some richness and abundance variables may not have led to cumulative declines because individuals displaced one year may have been replaced in subsequent years, and some individuals each year may have habituated to or learned to tolerate the intrusions. For the avian communities and intrusion levels we studied, managers should focus on trying to preclude or ameliorate short-term impacts. Attempts to identify the types and intensities of intrusion that actually cause cumulative declines in richness and abundance should continue. Data about intrusions that do not generate cumulative declines, such as those presented here, are just as important as data about intrusions that do cause cumulative declines; managers need both to define the scope of intrusion disturbances that can lead to cumulative impacts in avian communities. Information about the cumulative effects of intrusion should be used by conservation biologists, wildlife managers, and land-use planners to decide whether or how to control intrusion.
The U. S. Fish and Wildlife Service (Service) began the process of developing a Comprehensive Conservation Plan (CCP) for the Desert National Wildlife Refuge Complex (Desert Complex) in fall 2001. Public, agency, and tribal involvement was an important part of the CCP process, with five scoping meetings held during the first year of the planning process, and multiple interagency and tribal meetings and workshops to address topics related to visitor services, cultural resources, and wildlife and habitat management. The Draft CCP/Environmental Impact Statement (EIS) was made available for public review and comment from July 11, 2008, through September 9, 2008. The Draft CCP/EIS has been revised to respond to public comments to produce the Final CCP and Final EIS. A Record of Decision will be signed within 30 days after the availability of the Final CCP and EIS is announced in the Federal Register.
The Desert Complex, consisting of the Ash Meadows National Wildlife Refuge (NWR), Desert NWR1, Moapa Valley NWR, and Pahranagat NWR, is located in Nye, Clark, and Lincoln counties in southern Nevada (Figure 1). Ash Meadows NWR is located northwest of Pahrump, Nevada, less than 5 miles from the California-Nevada border and encompasses approximately 24,000 acres (Figure 2). Desert NWR is located less than 10 miles north of Las Vegas and encompasses more than 1.6 million acres, making it the largest refuge in the continental U.S. (Figure 3). Moapa Valley NWR is located northwest of Moapa and encompasses approximately 116 acres of land (Figure 4). Pahranagat NWR is located at the northeastern corner of the Desert NWR, just south of Alamo; this Refuge encompasses more than 5,000 acres (Figure 5). Ash Meadows and Moapa Valley NWRs were established to protect endangered and threatened species, Desert NWR was established to protect desert bighorn sheep and other wildlife, and Pahranagat NWR was established to provide a habitat for migratory birds.
Ash Meadows NWR provides habitat consisting of spring-fed wetlands and alkaline desert uplands for at least 25 plants and animals found nowhere else in the world. The Refuge has a greater concentration of endemic life than any other local area in the U.S. and the second greatest concentration in all of North America. Desert NWR provides a wide range of upland habitats, from saltbush scrub to coniferous forests, as well as natural springs and wetlands. The Refuge provides one of the largest contiguous blocks of habitat for
