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At least 199 records · Page 11Linked to original sources

USGS1982

Recurrence, mortality, and dispersal of prairie striped skunks, Mephitis mephitis, and implications to rabies epizootiology

Detailed study of radio-equipped individuals of the Striped Skunk (Mephitis mephitis) in a North Dakota population provided insight into possible mechanisms for spread of rabies during spring and summer. Annual recurrence rates of 138 skunks marked on a study area averaged 11% for adult males, 43% for adult females and 9% for kits. Population changes were from mortality (including rabies) and dispersal. Five instances of adult dispersal (four by males) were recorded; maximum straight-line distance was 119 km. Some males initiated dispersal in spring. Communal denning by adults occurred rarely after whelping began but resulted in intraspecific conflict. Evidence of intraspecific and interspecific strife leading to kit mortality and some adult mortality was found at dens of 9 of 40 litters studied.

Canadian Field-Naturalist↗

USGS2014

Comprehensive framework for ecological assessment of the Migratory Bird Habitat Initiative following the Deepwater Horizon oil spill

Following the Deepwater Horizon oil spill in the Gulf of Mexico in April 2010, the USDA Natural Resources Conservation Service (NRCS) established and funded the Migratory Bird Habitat Initiative (MBHI), with the goal of improving and increasing wetland habitats on private lands to benefit wintering and migrating waterbirds displaced from oil-impacted coastal wetlands. The NRCS and conservation partners provided financial and technical assistance to landowners and managers of sites enrolled in various conservation easement programs, and incorporated approximately 190,000 ha of wetlands and agricultural lands in the Mississippi Alluvial Valley (MAV) and Gulf Coast regions in the MBHI. In fall 2010, the NRCS worked with scientists and graduate students from three universities and various conservation agencies to design and implement landscape-scale evaluations of (1) the use of MBHI-managed wetlands and comparable non-MBHI wetlands by Charadriiformes (shorebirds), Anseriformes (waterfowl), and other waterbirds; and (2) the relative effectiveness of different MBHI practices for providing habitat and food resources for migrating, resident, and wintering waterbirds. In this paper, we describe the scientific framework designed to evaluate the MBHI in improving waterbird habitats on private lands in the MAV, the Gulf Coast Prairies in Louisiana and Texas, and Gulf coastal wetlands of Mississippi and Alabama. The results of our evaluation will enhance our understanding of the influence of MBHI, other Farm Bill Conservation Initiative managed lands (e.g., Wetland Reserve Program), and selected agricultural working lands (e.g., Oryza sativa L. [Rice] fields in southern Louisiana and Texas) on wintering and migrating waterbirds. A proactive approach that uses science to evaluate governmental conservation programs is relevant and can inform development of meaningful public policy that likely will be needed for effective delivery of future conservation programs and to justify financial incentives paid to landowners to apply best management practices.

Southeastern Naturalist↗

USGS1982

Nocturnal activity and foraging of prairie raccoons (Procyon lotor) in North Dakota

Nocturnal activity and foraging of 39 radio-equipped raccoons ( Procyon lotor ) in eastern North Dakota were studied from April-July in 1974-1976. Sixteen of the raccoons were collected after foraging bouts for stomach content analysis. Raccoon activity consisted of running (13%), walking (49%) and local movement in confined areas (38%). Local movement was foraging on large or locally abundant food items. Adult males traveled farther in a night, ran twice as often, and moved locally only half as often as adult females and yearlings. Differences in activity patterns between adult females and yearlings were not detected. There was no difference among age-sex groups in use of foraging habitats. All raccoons foraged extensively in farmyards and wetlands. Stomach content analysis substantiated foraging determinations obtained by radiotelemetry. Principal foods were grain, aquatic animals, rodents, birds and bird eggs.

North Dakota↗

USGS2012

Fine-scale habitat use of reintroduced black-footed ferrets on prairie dog colonies in New Mexico

Black-footed ferrets ( Mustela nigripes ) are among the most endangered animals in North America. Reintroductions of captive-born ferrets onto prairie dog ( Cynomys spp.) colonies are crucial to the conservation of the species. In September 2007, captive-born ferrets were released on a black-tailed prairie dog ( Cynomys ludovicianus ) colony at the Vermejo Park Ranch, New Mexico. Ferret kits experimentally released in areas of comparatively low and high prairie dog burrow densities were located via spotlight surveys. Some maturing ferret kits were subsequently translocated to areas of low and high burrow densities on nearby prairie dog colonies. For 2 months, fine-scale habitat use was quantified by mapping all burrow openings within a 30-m radius of each ferret location. Spatial statistics accounted for autocorrelation in the burrow densities in areas used by ferrets. It was hypothesized that ferrets would select areas of high burrow densities within colonies; however, burrow densities in areas used by ferrets were generally similar to the available burrow densities. Because ferrets used areas with burrow densities similar to densities available at the colony level and because of the potential energetic benefits for ferrets using areas with high burrow densities, releasing ferrets on colonies with high burrow densities might increase reintroduction success.

New Mexico↗

USGS2018

Effects of feral horse herds on plant communities across a precipitation gradient

Feral horses are widespread in the western United States, with the majority of feral horse herds found in the Great Basin. There is a federal mandate to manage these herds in order to maintain “ecological balance”; however, understanding of the specific effects of feral horse grazing on rangeland plant communities in this region is incomplete. To address this research gap, we utilized long-term grazing exclosures and fenceline contrasts to evaluate the impacts of feral horses on several plant community variables (diversity, richness, dominance, and biomass) and species composition. Because the effects of grazing can vary with site precipitation and productivity, we selected 5 sites from 4 different rangeland types (Great Basin Desert, Colorado Plateau, Rocky Mountain grassland, and mixed grass prairie) that spanned a mean annual precipitation gradient of 229 to 413 mm. Our results did not reveal a significant effect of feral horse grazing on plant community composition, species richness, diversity, evenness, or dominance. In contrast, total aboveground herbaceous biomass and grass biomass were significantly reduced with feral horse grazing, but these effects did not vary with mean annual precipitation. Our results suggest that, at least at the sites we studied, feral horses have affected the plant community by reducing herbaceous biomass but have not caused plant community shifts. Additional multisite studies, preferably with standardized exclosures and larger sample sizes, would increase our understanding of feral horse grazing effects and inform management of feral horse herds in the western United States.

Colorado, Montana, Nevada, North Dakota, Utah↗

USGS2013

Nest success of grassland birds in oak barrens and dry prairies in west central Wisconsin

We investigated nesting success of grassland birds on dry prairie and oak barrens patches embedded within a forested matrix on Fort McCoy Military Installation. We monitored 280 nests of 9 grassland-bird species from mid-May to late July 2000–2002. Pooecetes gramineus (Vesper Sparrow) and Ammodramus savannarum (Grasshopper Sparrow) were the most abundant nesting species. Vesper Sparrow nest densities were highest on smaller grassland patches, while Grasshopper Sparrow nest densities were highest on the largest patches. Probability of fledging at least one young was 0.20 for Vesper Sparrow. For Grasshopper Sparrow, daily nest survival was higher for nests placed away from trees; probability of fledging at least one young was 0.28 for nests away from trees and 0.05 for nests near trees. Maintaining remnant native habitats is important, and management of woody features may help improve habitat quality for some grassland birds in Wisconsin.

Wisconsin↗

USGS2017

Nesting ecology of grassland birds following a wildfire in the southern Great Plains

We studied the response of nesting grassland birds occupying short-grass and mixed-grass prairie sites 2 and 3 y following two, large-scale wildfires that burned ≥360,000 ha in the Texas Panhandle in March 2006. Nest success was greater on burned plots compared to unburned plots, though this varied by species and year. Woody vegetation cover was greater around nests on unburned plots compared to burned plots for Cassin's sparrow ( Peucaea cassinii ) and lark sparrow ( Chondestes grammacus ). Cassin's sparrows and lark sparrows nested in more-woody vegetation than did grasshopper sparrows ( Ammodramus savannarum ), and woody vegetation was reduced following the wildfires. The wildfires appear to have had few if any negative influences on the avian community 3 years postfire. This may be due to grassland breeding birds being adapted to landscapes in which, historically, periodic disturbance (e.g., wildfire, intensive grazing by bison [ Bison bison ]) resulted in vegetation heterogeneity.

Texas↗

USGS2020

Greater sage-grouse chick killed by Great Basin gopher snake

Despite extensive range overlap between Great Basin gopher snakes ( Pituophis catenifer deserticola ) and Greater Sage-Grouse ( Centrocercus urophasianus ) within sagebrush ecosystems, there are few documented predator–prey interactions between these species. Although gopher snakes have been observed preying on nests of other prairie grouse, studies that used video-monitoring at sage-grouse nests found gopher snakes unable to consume sage-grouse eggs and reported just a single instance of a snake consuming a <1-day-old chick in a nest bowl. On the morning of 4 June 2018 at 04:55, we observed a Great Basin gopher snake killing, constricting, and attempting to consume a 19-day-old sage-grouse chick in the foothills of the Owyhee Mountains, southwestern Idaho. This observation is the first record of a gopher snake killing a sage-grouse chick during the late brood-rearing period and highlights the likelihood that large gopher snakes are a cause of chick mortality from hatch day to at least 19 days post-hatch.

Idaho↗

USGS2000

Abiotic factors affecting summer distribution and movement of male paddlefish, Polyodon spathula, in a prairie reservoir

Six male paddlefish, Polyodon spathula , were implanted with ultrasonic temperature-sensing transmitters and tracked during June through August 1997 to quantify effects of physicochemical conditions on their distribution and movement in Keystone Reservoir, Oklahoma. Paddlefish moved about twice as much during night than day. Movement rate of paddlefish was related to reservoir water level, inflow, and discharge from the reservoir at night; however, none of these variables was significant during the day. Location in the reservoir (distance from the dam) was negatively related to water level and positively related to inflow during day and night periods. Location in the reservoir was negatively related to discharge during the day. Paddlefish avoided the highest available water temperatures, but did not always avoid low dissolved oxygen concentrations. Paddlefish avoided the Cimarron River arm of the reservoir in summer, possibly because of high salinity. Our study demonstrates that distribution of paddlefish during summer and movement in Keystone Reservoir was influenced by physicochemical and hydrologic conditions in the system. However, biotic factors (e.g., food availability) not measured in this study may have been influenced by abiotic conditions in the reservoir.

Oklahoma↗

USGS2015

Black-tailed and white-tailed jackrabbits in the American West: History, ecology, ecological significance, and survey methods

Across the western United States, Leporidae are the most important prey item in the diet of Golden Eagles ( Aquila chrysaetos ). Leporids inhabiting the western United States include black-tailed ( Lepus californicus ) and white-tailed jackrabbits ( Lepus townsendi i) and various species of cottontail rabbit ( Sylvilagus spp.). Jackrabbits ( Lepus spp.) are particularly important components of the ecological and economic landscape of western North America because their abundance influences the reproductive success and population trends of predators such as coyotes ( Canis latrans ), bobcats ( Lynx rufus ), and a number of raptor species. Here, we review literature pertaining to black-tailed and white-tailed jackrabbits comprising over 170 published journal articles, notes, technical reports, conference proceedings, academic theses and dissertations, and other sources dating from the late 19th century to the present. Our goal is to present information to assist those in research and management, particularly with regard to protected raptor species (e.g., Golden Eagles), mammalian predators, and ecological monitoring. We classified literature sources as (1) general information on jackrabbit species, (2) black-tailed or (3) white-tailed jackrabbit ecology and natural history, or (4) survey methods. These categories, especially 2, 3, and 4, were further subdivided as appropriate. The review also produced several tables on population trends, food habits, densities within various habitats, and jackrabbit growth and development. Black-tailed and white-tailed jackrabbits are ecologically similar in general behaviors, use of forms, parasites, and food habits, and they are prey to similar predators; but they differ in their preferred habitats. While the black-tailed jackrabbit inhabits agricultural land, deserts, and shrublands, the white-tailed jackrabbit is associated with prairies, alpine tundra, and sagebrush-steppe. Frequently considered abundant, jackrabbit numbers in western North America fluctuate temporally and spatially. We also reviewed methods used to investigate jackrabbit populations, including spotlight line transects, flushing transects, drive counts, pellet plot counts, collections, roadside counts, mark-recapture studies, and radio-telemetry studies. Our review of jackrabbit literature illustrates a number of deficiencies in our understanding of jackrabbits in general. As an example, a detailed quantitative description of habitat preferences is lacking, as is a thorough understanding of sympatric jackrabbit species interactions. Even the existence of the oft-cited jackrabbit “cycle” is a matter of debate. Survey methods generally do not address efficacy or accuracy in measuring jackrabbit density or abundance. In addition, there is a paucity of information about jackrabbits in the Mojave Desert, with no real understanding of home ranges, habitat preferences, and population dynamics or demographics in this region.

Arizona, California, Colorado, Idaho, Iowa, Kansas↗

USGS2017

Grassland bird productivity in warm season grass fields in southwest Wisconsin

Surrogate grasslands established through federal set-aside programs, such as U.S. Department of Agriculture's Conservation Reserve Program (CRP), provide important habitat for grassland birds. Warm season grass CRP fields as a group have the potential for providing a continuum of habitat structure for breeding birds, depending on how the fields are managed and their floristic composition. We studied the nesting activity of four obligate grassland bird species, Bobolink ( Dolichonyx oryzivorus ), Eastern Meadowlark ( Sturnella magna ), Grasshopper Sparrow ( Ammodramus savannarum ), and Henslow's Sparrow ( A. henslowii ), in relation to vegetative composition and fire management in warm season CRP fields in southwest Wisconsin during 2009–2011. Intraspecific variation in apparent nest density was related to the number of years since the field was burned. Apparent Grasshopper Sparrow nest density was highest in the breeding season immediately following spring burns, apparent Henslow's Sparrow nest density was highest 1 y post burn, and apparent Bobolink and Eastern Meadowlark nest densities were higher in post fire years one to three. Grasshopper Sparrow nest density was highest on sites with more diverse vegetation, specifically prairie forbs, and on sites with shorter less dense vegetation. Bobolink, Eastern Meadowlark, and Henslow's Sparrow apparent nest densities were higher on sites with deeper litter; litter was the vegetative component that was most affected by spring burns. Overall nest success was 0.487 for Bobolink (22 d nesting period), 0.478 for Eastern Meadowlark (25 d nesting period), 0.507 for Grasshopper Sparrow (22 d nesting period), and 0.151 for Henslow's Sparrow (21 d nesting period). The major nest predators were grassland-associated species: thirteen-lined ground squirrel ( Ictidomys tridecemlineatus ), striped skunk ( Mephitis mephitis ), milk snake ( Lampropeltis triangulum ), American badger ( Taxidea taxus ), and western fox snake ( Elaphe vulpina ). Overall depredation rate was not affected by the number of years since the site had been burned. The diversity of vegetation on warm season CRP fields created by management using fire provides a continuum of structure for obligate grassland birds to use for breeding and habitat for a diversity of nest predators.

Wisconsin↗

USGS1975

Death feigning by ducks in response to predation by red foxes (Vulpes fulva)

Predation by captive red foxes ( Vulpes fulva ) on approximately 50 ducks comprised of five species was observed in tests conducted at the Northern Prairie Wildlife Research Center, Jamestown, North Dakota. Most ducks were attacked from a rear or lateral position and seized in the cervical or thoracic region. All birds became immobile (death-feigned) immediately when seized and with few exceptions remained motionless during prey-handling and for varying lengths of time thereafter. Initial death feints lasted from 20 sec to 14 min. Recovery was delayed by tactile, visual and, possibly, auditory cues from the foxes. Death-feigning birds appeared alert and often took advantage of escape opportunities. Twenty-nine birds survived initial capture and handling by the foxes. Naive foxes were wary of ducks during initial confrontations, but experienced foxes showed little hesitation in attacking them. After capture, most ducks were taken alive to lay-down sites where they were mouthed and often killed. Then the ducks were usually cached or taken to dens or pups. Several birds were cached alive. Red foxes appear to have adapted to the escape of death-feigning ducks by learning to kill some birds soon after capture and by the evolution of an appendage-severing behavior. Death feigning appears to be a highly developed antipredator behavior of ducks that facilitates the escape of some birds after capture by red foxes.

American Midland Naturalist↗

USGS2007

Pattern and potential causes of White-faced Ibis, Plegadis chihi, establishment in the northern prairie and parkland region of North America

The Northern Prairie and Parkland Waterbird Conservation Plan calls for renewed attention to determining the current status of waterbird populations, their distributions, and conservation needs. It highlights the need for baseline information on the White-faced Ibis (Plegadis chihi). In response, we examined the historical and current distribution of the ibis in North Dakota and summarized first sightings and nest records for the provinces and other states composing the northern prairie and parkland region. The establishment of breeding colonies of White-faced Ibis here may be due to climate and precipitation patterns, invasion and spread of Narrowleaf Cattail (Typha angustifolia), changes in agricultural practices, habitat loss and range expansion in the southern and western portions of the species' range, and increases in ibis populations in the Intermountain West. We placed special emphasis on North Dakota, a state for which there is scant published information concerning the current status of this species. In recent decades, the ibis has become a regular breeding-season resident in North Dakota and in other areas of the northern prairie and parkland region. From 1882 to 2002, there were 145 reports of one or more White-faced Ibis in North Dakota, including 93 reports during the breeding season (15 May to 31 August), 49 during the non-breeding season (1 September to 14 May), and three for which the season of occurrence was not reported. Prior to the 1960s, there were only three records of the species in North Dakota. Observations of White-faced Ibises in North Dakota increased dramatically between the 1960s and the early 21st century, and the species has been observed nearly annually since 1971. The first White-faced Ibis nesting activity in the state was recorded in 1978, and to date, there have been 21 known records of nesting activity in the state. The species nested in large (>300 ha) semipermanent or permanent wetlands within mixed-species colonies ranging in areal extent from small (0.1 ha) to fairly large (27 ha), and colonies were located in patches of emergent vegetation dominated by cattails (Typha) and bulrushes (Scirpus). We classify the White-faced Ibis as a fairly common migrant and a locally uncommon breeder east of the Missouri River and a casual migrant west of the Missouri River.

Canadian Field-Naturalist↗

USGS1973

Selective predation by mink, Mustela vison, on waterfowl

Predation by mink ( Mustela vison ) on three types of ducks (captive, pen-reared-released and wild) was documented in two studies at the Northern Prairie Wildlife Research Center, Jamestown, North Dakota. In the first study, 36 of 60 flightless adult and juvenile ducks held on eight 0.1-acre experimental ponds disappeared between 10 July and 4 August 1969. Available evidence indicated that all were killed by a large adult mink. The mink selected recently released incubator-hatched ducklings, females in the process of incubating, and adults and juveniles on a marginal food supply.In the second study, 152 wood duck ducklings ( Aix sponsa ) were released on a 76-acre marsh during 1971. Half of the ducklings, when 24 to 27 days old, were placed at weekly intervals in four floating pens and allowed to escape after 4 days. Each time birds were placed in the floating pens, a comparable group was placed in a predator-proof shoreline pen. Birds in the shoreline pen escaped as they learned to fly when approximately 60 days old. The shoreline of the marsh was periodically searched, and the remains of 21 (28%) of the floating-pen birds were identified in food remains found at 16 mink dens. No remains of birds from the shoreline pen were found at the dens. Coots ( Fulica americana ) were also taken commonly. Wild ducklings appeared to have been almost totally consumed, but the legs and feet of the wood ducks were often left uneaten because of bands and tags.

American Midland Naturalist↗

USGS1949

Wildlife effects of DDT dust used for tick control on a Texas prairie

The effect of DDT dust on wildlife was studied at Camp Bullis, Bexar County, Texas, in the summer of 1947. Studies were made on a 206.6 acre plot that was treated with DDT for experimental control of the Lone Star tick ( Amblyomma americanum ). A dust consisting of one part of DDT to nine parts of pyrophyllite was applied at an average rate of 4.4 pounds of DDT per acre. The limits of DDT concentration that affected wildlife cannot be stated exactly because of a heavy rain that fell near the end of the dusting, and because of irregularity in DDT deposition. Since absolute uniformity of dusting could not be expected in any large scale DDT application, the effects observed in these trials were probably fairly representative. However, continued dry weather would have permitted longer exposure to DDT, possibly with more severe effects than those found in this study. The vegetation of the experimental area was roughly 70 percent ungrazed tall-grass prairie and 30 percent trees and shrubs. Ground and bush feeding birds were severely affected. Cardinals, lark sparrows, field sparrows, Bewick's wrens, Carolina wrens, Kentucky warblers, yellow-breasted chats, blue grosbeaks, and painted buntings were nearly or entirely eliminated from the treated area. Birds affected, but less drastically reduced in numbers, were yellow-billed cuckoo, black and white warbler, yellow-throated vireo, and white-eyed vireo. Birds found dead in the DDT area were 9 cardinals, 2 painted buntings, 2 lark sparrows, 1 yellow-breasted chat, and 1 white-eyed vireo. Bird mortality had begun by the day after dusting and was largely over by the end of the fifth day. Census of deer in DDT and check areas before and after treatment showed no reduction in deer numbers and no diminution in use of the DDT area. No deer or fawns were found dead or affected. Box-trapping of raccoons in DDT and check areas before and after treatment showed no effects that could be attributed to DDT. Limited observations on armadillos, striped skunks, and rabbits gave no indication of pronounced damage to these forms. No mammals of any kind were found dead or affected in or near the DDT area. Four rough green snakes and one Texan spiny lizard were found dead in the DDT area. Mortality was probably high among insectivorous reptiles.

Texas↗

USGS2007

Sex differences, effects of male presence and coordination of nest visits in prairie voles (Microtus ochrogaster) during the immediate postnatal period

Little is known about sex differences in parental behavior of biparental mammals and if mates in such species coordinate care of young. We studied parental care displayed by prairie voles (Microtus ochrogaster) under seminatural laboratory conditions during the first 3 d of life of their offspring. Through direct observations and videotaping, we monitored members of male-female pairs to determine if sex differences in early parental behavior exist and if mothers and fathers coordinate visits to the nest. To assess the impact of fathers on survival of pups and behavior of mothers, we also examined parental care displayed by single females toward their young. Male and female members of breeding pairs differed dramatically in degree of parental care. Females spent more time in the nest with young and licked them more frequently than did males. Additionally, females maintained the nest more frequently than did males, whereas they maintained runways less frequently. Although coordination of visits to the nest was not perfect between members of pairs, pups of pairs were left alone for less time than were pups of single females. Parental behavior displayed by paired and single females did not differ, nor did survival of their young to day 3 or 15. We suggest that provision of ample space and cover to vole parents rearing young in captivity promotes expression of sex differences in parental behavior, but that even seminatural conditions are not sufficient to yield benefits of father presence to survival of young. Under more challenging conditions, such as cold temperatures or presence of predators, benefits of father presence might emerge.

American Midland Naturalist↗

USGS2012

Importance of lunar and temporal conditions for spotlight surveys of adult black-footed ferrets

Black-footed ferrets (Mustela nigripes) spend most daylight hours underground in prairie dog (Cynomys) burrows and exhibit aboveground movements primarily at night. Moonlight can influence the activity patterns of ferrets and, consequently, might influence the efficiency of spotlight surveys used by biologists to monitor ferret populations. We related detection of adult ferrets during postbreeding spotlight surveys to lunar and temporal conditions. We most frequently located ferrets during surveys in which the moon breached the horizon. The data suggested intersexual differences in response to moonlight. We located male ferrets most frequently during nights with greater moon illumination, but we did not detect a correlation between moon illumination and spotlight detection of female ferrets. In general, moonlight could facilitate aboveground navigation by ferrets. However, it seems activity under bright moonlight could be costly for female ferrets while they raise young. Detection of ferrets also varied among months. We detected female ferrets most frequently in August–September, when mothers increase hunting efforts to acquire prey for growing offspring (kits). Detection of adult female ferrets declined in October, when kits were likely independent of their mother. We located male ferrets most frequently in September–October, when males might increase activity to monitor female ferrets and male competitors. Consideration of lunar and temporal influences and standardization of postbreeding surveys could enhance site-specific assessment of reintroduction success and across-site assessment of species recoveiy progress. We suggest that postbreeding surveys for ferrets should be enhanced by concentrating efforts in August–September during moonlit nights when the moon is above the horizon.

Western North American Naturalist↗

USGS2020

Visualizing the ecological importance of pre-Euro-American settlement fire across three Midwestern landscapes

Bearing-tree data were used to calculate an index, pyrophilic percentage, depicting the importance of fire before Euro-American settlement on three landscapes, two within the Prairie Peninsula and one outside the region. Based on functional traits, bearing trees were classified as either pyrophilic or pyrophobic, applied to Public Land Survey points, and the pyrophilic percentage was calculated for each point. Kriging was applied to this point database to create a continuous surface of pyrophilic percentages. Regression analysis was used to relate this surface to environmental factors. Regression models created separately for each study area explained 38 to 53% of the variation in pyrophilic percentage. A positive association between pyrophilic percentage and distance to water and summer potential evapotranspiration was consistent across all study sites. The consistently high values and spatial patterns of pyrophilic percentage revealed fire-dominated landscapes interspersed with patches of pyrophobic vegetation. The restriction of pyrophobic areas to the leeside (east) of waterbodies indicated these served as firebreaks in a fire-swept landscape. Lake Michigan must have had a profound effect on pre- Euro-American settlement fire environments, serving as a massive physical firebreak while casting a moist maritime climate eastward. In southern and southwestern Illinois, the Mississippi River and associated tributaries along with an increase in topographic complexity also served as firebreaks, with pyrophobic forests restricted to riparian zones which progressively graded to pyrophilic vegetation on surrounding uplands. Our analysis expands the use of Public Land Survey data by converting bearing trees into a meaningful fire ecology index. While much of the landscape included in our study area is now in agriculture or urbanized, pyrophilic percentage maps can help guide land managers in the application of fire for restoration, conservation, and forestry purposes.

Illinois, Indiana, Michigan, Wisconsin↗