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Habitat loss from agricultural expansion is one of the leading causes of endangerment for terrestrial vertebrates. Restoration programs such as the Conservation Reserve Program (CRP) and State Acres for Wildlife Enhancement (SAFE) were initiated in part to ameliorate grassland loss. Previous assessments of grassland restoration efforts have not focused on medium and large mammals because of sampling difficulties. More generally, few assessments of restoration outcomes consider effects of landscape context. We integrated camera trapping with occupancy modeling to assess mammal responses on 30 restored grassland sites in a dynamic agroecosystem in Illinois from 2014 to 2015. We tested hypotheses about the effects of local habitat conditions and landscape context on use of restored grasslands by four focal species: raccoons (Procyon lotor), eastern cottontails (Sylvilagus floridanus), coyotes (Canis latrans), and white-tailed deer (Odocoileus virginianus). Most species showed seasonal differences in grassland use that reflected the dynamic nature of the surrounding agricultural matrix (i.e., loss of hiding cover and supplemental food from crop harvesting). Landscape context also was important; species occurrences were related to grassland size and isolation, distances to human structures, and distances to nearest forest. The red fox (Vulpes vulpes) was not detected on any site, despite >5000 camera nights of sampling, indicating further research is needed to understand how competitive interactions with coyotes might limit the distribution of this smaller canid. Grasslands created by the CRP and SAFE programs provide habitat for medium and large mammals. Understanding how use of these habitats depends on landscape context can enable managers to strategically place new grasslands to either promote colonization by games species or to deter use by raccoons, an important predator of grassland bird nests.
Understanding population genetic structure provides insight into the evolutionary past, present, and future of a species. In this study, we examine the range-wide population genetic structure of the prairie vole, Microtus ochrogaster (n = 170). Early work divided M. ochrogaster into seven subspecies using morphological characteristics. We hypothesized polymorphic microsatellite data would reveal a genetic structure roughly congruent with the current classification of subspecies based on their geographic boundaries. We predicted populations within the geographic range of one subspecies would be genetically distinguishable from populations within the geographic range of another subspecies. Microsatellite data from the seven putative subspecies suggested ∼90% of molecular variation was within populations. A STRUCTURE cluster analysis had a best supported k = 3, but most individuals were admixed for the three genetic clusters, and only individuals of M. o. ohionensis were distinctive in being essentially represented by a single cluster. Therefore, our molecular data showed evidence of relatively high gene flow and little geographic differentiation throughout the range of the six contiguous subspecies. The subspecific classification of M. ochrogaster should be re-evaluated using a comprehensive taxonomic approach that combines molecular, morphometric, and other data.
The fisher (Pekania pennanti) is a forest-dwelling mesocarnivore native to northern North America. The species had been extirpated from many southern parts of its historic range, but several states have implemented fisher re-introduction programs over the past 40 y. While many studies have previously examined fisher diet, most occurred in northern and western portions of the species' range where mixed and coniferous forests are the dominate cover types. We examined fisher diet, in a re-introduced population in the central Appalachian Mountains where deciduous forests were the dominate cover type. We collected 91 fisher carcasses from 2002–2014 and examined their stomach contents. We detected mammalian and avian prey in 82.6% and 10.9% of stomachs, respectively. Fishers we sampled consumed a variety of plant materials (n = 11) and prey items (n = 30 spp.). Diet composition of males and females overlapped considerably (O = 0.87). Our most noteworthy and novel finding was the presence of fisher remains in 11 (12%) stomachs. We suggest here that rapid population growth of Pennsylvania fishers may have resulted in aggressive behaviors underlying our observations of interspecific consumption. Future research that examines the cause for intraspecific consumption in this central Appalachian fisher population would be a worthy endeavor.
American marten are associated with forests that are characteristically late successional, closed canopy, and diverse in structure; these attributes meet their habitat requirements and provide resting sites. However, the small populations of marten in Michigan's Northern Lower Peninsula face modern habitat conditions that are fragmented and considerably altered from presettlement environments. Resting site structures are required habitat components that are used daily and provide protection from predation and inclement weather but may be limiting and require active management to preserve. We identified resting site characteristics of American marten in the Manistee National Forest from May 2011 to December 2013. Twenty-five marten (15 male and 10 female) were monitored to identify resting sites. We identified 522 unique resting site structures; tree cavities (n = 255, 48.9%), branches (n = 162, 31%), and nests (n = 90, 17.2%) were most commonly observed. During the summer (April–September) marten used more exposed tree branches (41.8%); while in the winter (October–March) they used more cavities (64.5%). Marten used structures that were associated with high percent canopy closure (≥67%). Resting sites were found in live trees 86% of the time, and the three predominant species included oak (Quercus spp.), maple (Acer spp.), and red pine (Pinus resinosa). Trees used as resting sites had significantly larger mean diameter at breast height (DBH) than the average DBH of nonresting site trees found at resting site locations (U′ = 268721, P = < 0.001). The average stand basal area (x¯ = 33.92 ± 9.04 m2 ha) found in resting site plots was significantly larger than that found at control plots (x¯ = 31.10 ± 8.69 m2 ha, P = 0.007). Maintaining complex forest structure, abundant CWD, high percent canopy closure and high basal area should be considered when managing for marten. Silvicultural techniques that promote tree species diversity, older tree age classes, and retention of CWD are all important factors to consider when managing for marten.
Floodplain forest of the Upper Mississippi River is important for songbirds during spring migration. However, the altered hydrology of this system and spread of reed canary grass (Phalaris arundinacea) and emerald ash borer (Agrilus planipennis) threaten tree diversity and long-term sustainability of this forest. We estimated tree preferences of songbirds during spring migration 2010–2013 to help guide management decisions that promote tree diversity and forest sustainability and to evaluate yearly variation in tree selection. We used the point center-quarter method to assess relative availability of tree species and tallied bird foraging observations on tree species as well as recording the phenophase of used trees on five 40 ha plots of contiguous floodplain forest between La Crosse, Wisconsin and New Albin, Iowa, from 15 April through 1 June. We quantified bird preferences by comparing proportional use of tree species by each bird species to estimates of tree species availability for all 4 y and for each year separately. Species that breed locally preferred silver maple (Acer saccharinum), which is dominant in this forest. The common transient migrant species and the suite of 17 transient wood warbler species preferred hackberry (Celtis occidentalis) and oaks (Quercus spp.), which are limited to higher elevations on the floodplain. We observed earlier leaf development the warm springs of 2010 and 2012 and later leaf development the cold springs of 2011 and 2013. Yellow-rumped Warbler (Setophaga coronata), American Redstart (S. ruticilla), Warbling Vireo (Vireo gilvus) and Baltimore Oriole (Icterus galbula), and the suite of transient migrant wood warblers spread their foraging efforts among tree species in colder springs and were more selective in warmer springs. All three of the important tree species are not regenerating well on the UMR and widespread die-off of silver maple is possible in 50 y without large scale management.
Habitat requirements are essential knowledge for the conservation of narrowly endemic species. Basic ecological information is unavailable for most crayfish species, including the Tennessee bottlebrush crayfish, Barbicambarus simmonsi. To obtain ecological data, we conducted surveys for B. simmonsi within the Shoal Creek drainage in Lawrence County, Tennessee and Lauderdale County, Alabama from Summer 2013–Spring 2014. The objectives of our study were to determine distribution and habitat use of Barbicambarus simmonsi. Our work increased the number of known sites for the species from three to 14 across Shoal Creek, showing that they occupy a 38.6 km stretch of the creek. Habitat use modeling did not yield significant results, but observations show that crayfish use large flat boulders as habitat, with over 96% of crayfish found under such habitat. We conclude that while habitat modeling is an effective tool we should not overlook the importance of field observations as a contributor to natural history.
The southeastern blue sucker population in the lower Pearl River that runs through Louisiana has been impacted historically by numerous natural and anthropogenic habitat alterations, with collection records indicating a significant population decline in this system over recent decades. Electrofishing surveys, radio telemetry, and bathymetry and habitat mapping were used to examine relative abundance, movements, and habitat associations of southeastern blue sucker in the lower Pearl River. Relative abundance of southeastern blue sucker was lower relative to other large benthic Pearl River species. Radio telemetry surveys indicated southeastern blue suckers exhibited small home ranges, limited movements, and strong associations with upstream outside edges of deep bends that were characterized by gravel substrates and woody debris. Increased consideration for elevating southeastern blue sucker conservation status in the lower Pearl River system may be warranted given their high habitat specificity, apparent low recolonization potential, and susceptibility to continuing degradation of their associated habitats.
Purposes of this study were to assess population status and life history attributes of the Texas Shiner Notropis amabilis, a minnow endemic to the Edwards Plateau region in Texas and the Rio Grande drainage of U.S.A. and Mexico. Despite possible extirpation from three stream reaches, populations of Texas Shiners persist with abundances categorized as occasional and frequent among multiple and independent stream reaches, streams, and drainages. Therefore, Texas Shiner population is considered stable. Quantification of life history traits suggest Texas Shiner has a protracted reproductive season (i.e., 9 mo), a life span of 2 y, and feeds on primarily aquatic invertebrates. Protracted spawning seasons are consistent with Texas Shiner's reported associations with spring systems of the Edwards Plateau. Current and future conservation of N. amabilis and other spring-associated fishes are explicitly linked to spring complexes, although exact mechanisms of association are unknown.
Nothocalais cuspidata (Pursh) Greene (Asteraceae) is a plant species of conservation concern in Missouri; it typically occurs as isolated populations in hill and sand prairies which are themselves rare and fragmented habitats. The present study was undertaken to understand its reproductive biology as a hill prairie member and the possibility of reduced reproductive output in this isolated habitat. Nothocalais cuspidata is an early spring-flowering, nonclonal, primarily self-incompatible perennial that exhibits a 4 wk flowering phenology with most florets open to cross-pollination over a 2–3 wk period. The attractive UV reflective florets were visited by six species of halictid and solitary bees. The study population did experience depressed reproductive output in 2014 compared to 2004, with open-pollinated florets producing 19.1% fewer fruits than in 2004 along with a 37% decline in population size over a 13 y period. We suggest the depressed fruit production experienced is likely due to the unpredictable spring weather associated with early flowering and sporadic pollinator visitation in an isolated habitat leading to large variations in reproductive success over time or a reduction in compatible mating types as the population declines.
Polyploidy is common in nature, particularly among plants, and is often associated with significant morphological, ecological, and evolutionary change. These changes may contribute to prezygotic and postzygotic isolation between cytotypes; therefore, polyploidy is commonly thought to lead to speciation. Recent work suggests prezygotic mechanisms may be more important in determining isolation than postzygotic mechanisms. We compared the reproductive ecology of populations of diploid and tetraploid Galax to assess the potential for gene flow between the cytotypes. Galax urceolata is native to the southern Appalachian Mountains and is a natural polyploid series with diploid, triploid, and autotetraploid individuals occurring in uniform and mixed-cytotype populations. We found the temporal peak of flower production in tetraploids slightly preceded that of diploids; however, the overall distributions of flowering phenologies were similar. Hymenoptera and Diptera were the most common floral visitors and diploids were visited slightly more often than tetraploids; however, there were no differences between cytotypes in terms of the taxonomic composition of their floral visitors. Seed production is likely pollen limited, but again this does not differ between cytotypes. While tetraploids produced more flowers than diploids, there was no difference in fruit production. Finally, our data suggest that Galax urceolata is self-incompatible. In sum we found few differences in the reproductive ecology of diploid and tetraploid Galax, which when combined with obligate outcrossing increases the potential for gene flow between cytotypes and reduces the likelihood of differentiation.
Restoring Midwestern oak savannas and woodlands over the long term requires balancing mortality of large oaks with recruitment of oaks into large size classes. At restoration sites in northwestern Ohio, we tracked survival of large oak trees (≥20 cm in stem diameter) and recruitment between 2002 and 2015 after initial tree thinning and prescribed burning treatments. The 24 study sites spanned a gradient of canopy cover from unrestored forests to restored woodlands and savannas. Of 141 large black oak (Quercus velutina) and white oak (Quercus alba) trees alive in 2002, 79% were alive 14 y later. Large oak survival varied among vegetation types, with restored savannas not losing a single tree, compared with 18% mortality in unrestored forests and 28% mortality in restored woodlands. At least some mortality in the woodlands was associated with a tornado that damaged two sites. Diameter distributions changed over the 14 y in all three vegetation types. Unrestored forests shifted toward proportionally greater large and fewer small diameter oaks. Meanwhile, restored woodlands, despite having the highest mortality of large oaks, still exceeded, via recruitment of new large oaks, the reconstructed pre-Euro-American-settlement tree density. Restored woodlands and savannas exhibited four-fold increases in oak recruitment potential (saplings 1 to 10 cm in diameter) between 2002 and 2015. Ecological restoration processes have been compatible with conserving large oaks and sustaining oak recruitment potential.
Clinch Dace (Chrosomus sp. cf. saylori), discovered in 1998, is a species of fine-scaled dace confined to northern tributaries of the Upper Clinch River watershed. Only one previous study has documented spawning behavior of Clinch Dace. On June 4–6, 2014, we observed Clinch Dace exhibiting staging and possibly spawning behavior over a gravel nest constructed by either Campostoma or Semotilus. We recorded five video clips totaling over 1 h of spawning behavior. We quantified various behaviors, including: long duration chases, short duration chases, Clinch Dace chasing other species, other species chasing Clinch Dace, Clinch Dace benthic feeding, other species benthic feeding, and nest construction. Analysis revealed an increase in all recorded behaviors between 4 June and 6 June. We speculate 4 June was territorial prespawn behavior and 6 June represented mid spawn/post spawn behaviors. Comparison of spawning observations of all southern Chrosomus species indicates the Clinch Dace is similar to other Chrosomus species in that they seem to prefer pit style nests and exhibit similar spawning aggregation behavior. However, other Chrosomus species in some cases spawn without hosts and seem to spawn within a more specific temperature range than Clinch Dace.
False map turtles (FMT, Graptemys pseudogeographica) are found along the Missouri and Mississippi Rivers throughout the United States but are a protected species in South Dakota (SD). Graptemys pseudogeographica blood samples were collected from two sites above and below the Gavins Point Dam along the Missouri River near Yankton, SD for the purposes of creating a microsatellite library. We isolated and characterized ten microsatellite loci in G. pseudogeographica, and only one locus (FMT201) shows as deficit of heterozygotes relative to expectations.