information, or to report sightings of
|>>"Cow cliffs" just north of Big Creek Bridge. 15 roadkilled larger animals (mainly deer) have been recorded from a 1.5 mile stretch of highway fronting Big Creek Reserve.|
|Current results (as of 2-03) of the Big Sur Road Kill Survey are summarized as follows:|
|Summary: The purpose of this survey is to (1) help identify and locate roadkill "hot spots" that may correspond with wildlife corridors, (2) to illustrate the magnitude of roadkill within the corridor, (3) to determine the diversity of species affected, and (4) provide useful information and guidance for the Big Sur Coast Highway Management Plan. Approximately 20 people participated in the survey, and they reported approximately 375 roadkill sightings between October 2000 and February 2003. Reported sightings included at least 24 species of mammals and birds, including bobcats, coyotes, foxes, deer, raccoons, opossums, turkeys, and wild pigs as well as many smaller species. There were two distinct seasonal peaks, one in late spring consisting of mostly smaller animal species, and another larger peak in late summer, including larger as well as smaller species. Some Coast Highway "neighborhoods" had higher frequencies of roadkill than others, and these seemed to correspond to traffic speed or some other correlate of the terrain, with reduced kill on rugged, winding parts of the highway. Close examination of the reported locations of roadkill revealed concentrations in certain areas, suggesting that it may be fruitful to concentrate further investigation and possible mitigation in a few more restricted spots. These "hotspots" tend to be straightaways with high traffic speed and areas of productive habitat on both sides of the road, especially near streams or springs. More information is needed, as two years is not enough to detect inter-annual variations, and we need more observation to define areas where remediation might be considered.|
Survey Description and Methods
Year 1 files (a record of last years' report, for purposes of comparison)
Excel data file
Kill reporting by neighborhood
Identification of "hotspots"
List of candidate "hotspots"
Coast Highway Management Plan
|Species Reported: The 375 reported roadkills included 70 deer and 3 wild boar, animals large enough to create a traffic safety hazard. There were 82 kills of medium-sized animals such as coyotes, foxes, raccoons, and opossums. These two categories were lumper together under the "large" category in the analysis below. Rabbits, squirrels and snakes made up the majority of the smaller animals recorded, but the total did include such unusual animals as ringtails and spotted skunks. More detail may be seen on the species list and in the excel file.|
|Roadkill reporting by neighborhood: The graph below summarizes the roadkill reported from 12 "neighborhoods" along the coast. Several reporting biases may be present. For instance, the paucity of roadkill in the extreme north may reflect a lack of reporting as few small animals were reported, and Big Sur residents may not realize that those areas were included in the survey. However, between Pacific Valley and Garrapata Coast the reporting is probably fairly even, with perhaps a trend of more reporting to the north. Thus, the reduced roadkill shown for the Lucia Coast and the Partington Coast probably represents a true reduction in the kill rate, suggesting that these neighborhoods are safer for wildlife with respect to being killed by vehicles. One possible explanation for these results is that these two neighborhoods are characterized by winding curves and somewhat reduced traffic speeds. Another is that the habitats in these neighborhoods include more rocky, steep terrain than in adjacent areas, and may be less desirable foraging and hunting areas for wildlife.|
|Seasonality This graph summarizes kill rates by month, illustrating the seasonal nature roadkill. As most reporting is by Big Sur residents there should be little bias in reporting effort as a function of season. Clearly there are two peaks in roadkill, one consisting primarily of smaller animals in the late spring and the other of larger and smaller animals in late summer|
Identification of "hotspots": The 6 graphs below show each roadkill event as a separate dot, unless there are 2 or more at the same milepost. Then the number of kills is shown for that spot. These graphs aid in pinpointing "hotspots" where multiple kills were reported from a small area.
Last year we tentatively identified 12 "2001 hotspots" or candidate areas within which to look more closely. These hotspots correspond with most of the 18 hotspots identified in the Corridor Intrinsic Qualities Inventory (Parsons Transportation Group 2002) using different selection criteria on the same data.
This year, with more data and more precise locations, we identified 23 hotspots, of which 12 included a substantial number of large animals while 14 included many small animals.