Ozark Research Articles

Studying drought-induced forest mortality using high spatiotemporal resolution evapotranspiration data from thermal satellite imaging

Drought can have pervasive and wide-spread impacts to forest health, as evidenced in several severe events occurring over the recent decades. Extensive forest die-off due to drought can impair the ecological functioning of forests, impacting habitat, water yield and quality from forested lands, and altering forest fire dynamics and intensity. Satellite remote sensing provides an effective means for detecting and monitoring spatial patterns of forest mortality over large areas, exploiting free and open long-term image archives available at a range in spatial and temporal resolutions. While remotely sensed surface reflectances and vegetation indices have been widely used to study optical response of forest canopies to drought events, retrievals of evapotranspiration (ET) derived from thermal satellite imagery – particularly at resolutions approaching crown scale - can provide insights into cumulative tree stresses that can incite disease and trigger mortality. In this study, we applied a multi-sensor satellite data fusion approach to estimate daily 30-m resolution ET and an associated Evaporative Stress Index (ESI) to study drought-induced mortality in a temperate forest at the Missouri Ozark AmeriFlux (MOFLUX) site, located in the central United States. The study covered the period from 2010 to 2014, including an exceptional drought year of 2012. Modeled ET agreed well with eddy flux measurements from the MOFLUX tower, with average monthly relative errors of 15%. Plot-scale ESI, describing temporal anomalies in the ratio of actual-to-reference ET, was used as an index of relative forest health to investigate relationships between forest mortality and drought severity. ESI showed good agreement with observed predawn leaf water potential, especially during the drought year. Furthermore, plot-scale ESI was also correlated with the subsequent year's tree mortality, suggesting the importance of considering the forest health condition prior to drought when studying drought-induced forest impacts. This study demonstrates the utility of multi-year ET remote sensing data at the stand or plot scale as an indicator of forest health and as a predictor of future mortality due to drought.

Female White‐tailed deer (Odocoileus virginianus) Behavior During Pregnancy, Parturition, and Lactation in 2 Contrasting Ecoregions

ABSTRACTLate gestation, parturition, and lactation are the most metabolically expensive periods for female ungulates, often requiring them to make trade‐offs between acquiring sufficient forage and reducing predation risk to neonates. Females alter movements and resource use depending on the stage of parturition; however, little is known about the influence of habitat type and fragmentation on parturition behavior. We evaluated how land use and habitat fragmentation affected white‐tailed deer (Odocoileus virginianus) space use, movements, and resource selection before, during, and after parturition in the highly fragmented glaciated plains (GP) and the more‐contiguous forested Ozark (OZ) ecoregions of Missouri, USA. We captured 127 pregnant female deer from January–March 2015–2017 and fitted them with global positioning system radio‐collars. We examined weekly home range sizes, space use shifts, movement speeds, and resource selection. Females in both study areas maintained stable movement speeds until the week of parturition when crepuscular movement speeds decreased significantly. Home range sizes were ≥150% smaller during the week of parturition compared to the third week before parturition in both study areas. Females shifted their space use 144 m (95% confidence interval [CI] = 830–252 m) in the GP and 162 m (95% CI 103–256 m) in the OZ between the week before parturition and the week of parturition. Females in both study areas exhibited similar patterns of resource selection before, during, and after parturition. Females consistently selected for Conservation Reserve Program grasslands in the GP and deciduous forests in the OZ, which could provide suitable forage for the female and adequate cover for the neonate. The similarity in movements and resource selection surrounding parturition in both areas, despite marked differences in land use and levels of fragmentation, suggests that the physiological cues of pregnancy and lactation may have the greatest influence on maternal behavior. © 2021 The Wildlife Society.

Long-term effects of organic matter removal, compaction, and vegetation control on tree survival and growth in coarse-textured, low-productivity soils

The Long-Term Soil Productivity Network is providing a systematic examination of the effects of organic matter removal and compaction on a variety of different soils and forest types across North America. Here we report on the 22nd-year survival and height growth of white oak (Quercus alba), northern red oak (Q. rubra), and shortleaf pine (Pinus echinata) on rocky, nutrient-poor soils that have a low to moderate water holding capacity in the Missouri Ozark Highlands. Treatments included three levels of organic matter removal (sawlog, whole tree, and whole-tree plus forest floor) and three levels of soil compaction (none: bulk density = 1.34 g cm−3; moderate: bulk density = 1.65 g cm−3; and severe: bulk density = 1.78 g cm−3) each with and without vegetation control. Following treatments, bareroot, 1–0 white oak, northern red oak, and shortleaf pine seedlings were planted at a 3:3:1 ratio, approximating the distribution of these species in this region. Within half of each plot, a vegetation control treatment was applied for the first 10 years by treating competing vegetation with herbicide. After 22 years, vegetation control significantly increased biomass and height of all planted species. The average height for northern red oak with vegetation control treatments was 884 cm with vs. 606 cm without; white oak was 837 cm with vs. 424 cm without; shortleaf pine was 1339 cm with vs. 1220 cm without. Moderate compaction increased average white oak height by 15% and severe compaction increased average height by 18% compared to no-compaction treatments. Compaction was not a significant treatment for red oaks or for shortleaf pines. However, the coarse fragments in the study soils appear to have muted much of the compaction to the soil’s fine-earth fraction and may have had the unintended effect of providing partial vegetation control. Whole-tree removal reduced average shortleaf pine heights by 6% vs. sawlog-only removal, while whole-tree + forest floor removal increased heights 3% compared to sawlog harvests. Organic matter removal was not a significant treatment for either oak species. Red oak survival probability was 0.79 with vegetation control vs. 0.34 without; white oak was 0.81 with vs. 0.65 without; shortleaf pine was 0.49 with vs. 0.45 without. Overall, vegetation control was the dominant factor driving survival and growth of oaks, and to a lesser degree, growth of shortleaf pine. Organic matter removal and compaction treatments had relatively little negative effect on height, indicating the resilience of these species to harvest-related disturbances in Ozark Highlands soils.

Forest management effects on downed dead wood at stand and landscape scales in a temperate forest of the central United States

Downed dead wood (DDW) is a critical component of forest ecosystems, with DDW dynamics largely affected by rates of input from standing trees to the forest floor and loss through decomposition or removal. Forest management decisions affect DDW dynamics based on the type of silvicultural harvest applied at the stand level and the administration of those treatments across the landscape. The Missouri Ozark Forest Ecosystem Project (MOFEP) is a landscape-scale experiment that tests the effects of three forest management treatments, even-aged management (EAM), uneven-aged management (UAM), and no harvest management (NHM), on forest ecosystems in the Ozark Highlands region of Missouri. In this study, we evaluate the effects of stand-level silvicultural treatments (clearcutting and intermediate thinning in EAM; single-tree selection and group selection in UAM) and landscape-level forest management treatments (EAM, UAM, and NHM) on the volume of DDW and distribution across decay classes over a 21-year period. At the stand level, clearcutting resulted in the greatest short-term increase in DDW volume among the silvicultural treatments. Following harvest, the DDW was primarily within the undecayed classes during the first few years after harvest but shifted to the greater decay classes during the second decade after harvest. At the landscape level, the forest management treatments did not differ in total DDW volume through time, although EAM and UAM had greater amounts of undecayed DDW than NHM shortly after harvest. Across all treatments, the volume of DDW increased through time, likely due to effects of the forest management but also due to background tree mortality related to oak decline during the study period. Overall, our results show differences in effects of stand-level silvicultural treatments on DDW dynamics and highlight the need to consider both stand-level and landscape-level effects of forest management systems in decision making.

Victoria L. Sork—Recipient of the 2020 Molecular Ecology Prize

Victoria L. Sork—Recipient of the 2020 Molecular Ecology Prize

Weatherscapes

The Ozark Mountains stretch from central Missouri into northern Arkansas and northeastern Oklahoma, as well as a touch of southeastern Kansas. Influenced by the dry air of the Great Plains, Canadia...

Seasonal periphyton response to low-level nutrient exposure in a least disturbed mountain stream, the Buffalo River, Arkansas

Like most streams located in the Ozark Plateaus, the Buffalo River in Arkansas generally has excellent water quality. Water-quality conditions in Big Creek, however, a major tributary of the middle Buffalo River, have been less favorable than that of other Buffalo River tributaries. Concerns regarding the influence of water quality in Big Creek on the Buffalo River magnified in 2013 when a large confined animal feeding operation (CAFO) began operating in the watershed. In response to these concerns, the U.S. Geological Survey compared monthly nutrient concentrations and seasonal periphyton assemblage metrics of a site on Big Creek downstream of the CAFO, two Buffalo River control sites upstream of the confluence with Big Creek, and three Buffalo River test sites downstream of the confluence with Big Creek. In addition to identifying potential nutrient patterns and periphyton responses along a low-level nutrient exposure gradient, the study determined how nutrient contributions from Big Creek (and the CAFO) are affecting ecological conditions and consequent ecosystem services in the Buffalo River. Nutrient and periphyton data exhibited more temporal than spatial variability. Nutrient concentrations were generally highest of all sites at the Big Creek site. Concentrations at the five sites on the Buffalo River were typically low (near laboratory reporting limits), and concentrations at the three test sites rarely exceeded those of the two control sites. An index developed with three ecologically relevant periphyton metrics (oligotrophic taxa and Homoeothrix percent relative abundance and mesotrophic diatoms percent taxa richness) suggested that nutrient uptake at sites downstream of the Big Creek-Buffalo River confluence resulted in subtle shifts in downstream periphyton assemblages. The periphyton index of biological integrity at control sites was slightly and generally more favorable compared to test sites. Even so, when periphyton data were considered in conjunction with both hydrology and water-quality data, the negative consequences of antecedent high flows and associated scouring exceeded the potential positive effects that low-level nutrients had on algal productivity. These findings emphasize the importance of comparing biological and chemical data across extended temporal scales, particularly when working with low-level nutrient gradients.

Prescribed burning reduces species richness of wood-decay fungi in the forests of northwest Arkansas.

The present study, which was carried out at three localities in the Ozark Mountains of northwest Arkansas, investigated the effects of prescribed burning on wood-decomposing fungi using samples of decaying woody debris (DWD) placed in plastic incubation chambers. One of the localities had not been subjected to recent prescribed burning, whereas the other localities contained both an unburned area as well as an area recently subjected to burning. In all three localities, small pieces of decaying woody debris (DWD) were collected, placed in the incubation chambers and the latter kept moist for any extended period of time. Pieces of DWD collected in the areas subjected to burning typically displayed evidence of considerable charring. Fruiting bodies appearing in the incubation chambers were removed and identified by sequencing of ribosomal DNA region. A total of 101 specimens representing 80 different taxa were recorded in the entire investigation, but the numbers of both specimens and taxa were appreciably higher for the unburned collecting sites. As such, the data obtained indicate that prescribed burning lowers the species richness of the wood-decomposing fungi associated with DWD at a particular locality. The unique aspect of the present study was the use of incubation chambers to characterize the taxa of fungi associated with CWD.

Sixty‐five years of fire manipulation reveals climate and fire interact to determine growth rates of Quercus spp.

AbstractMinimizing forest vulnerability to more frequent and severe droughts, as climate models predict, has emerged as a primary goal of forest management. One potential strategy to moderate drought‐induced stress is reducing basal area through the repeat application of prescribed fire. However, use of prescribed fire as a management tool to reduce drought vulnerability has been largely untested. Here, we report the long‐term effects of repeat fires on the climate‐growth response of adult oaks (Quercus spp.) in the Missouri Ozarks, USA. We measured the annual radial growth of trees that experienced either no fire, periodic (every 4 yr), or annual prescribed fires from 1950 to 2015. To assess whether increased fire frequency interacts with climate to determine long‐term forest productivity, we modeled annual growth as a function of potential evapotranspiration, fire treatment, and their interaction. We also quantified the effect of fire‐driven reductions in tree density on carbon and oxygen isotope composition of tree rings and drought resistance (growth during drought) and resilience (growth recovery after drought) during past drought events. Annual radial growth and isotopic composition data indicated trees experienced reduced growth due to moisture stress, but drought vulnerability did not vary between frequently burned forests and unburned controls. In contrast, periodic, but not annual, fires reduced annual growth by 9.6% during wet periods favorable to growth with the effect consistent over time. Fire had minimal effects on total and inorganic soil nitrogen after 65 yr of treatment, regardless of frequency, suggesting other underlying causes of the observed growth declines under periodic burning (e.g., crown, bole, or root injury). Our results suggest that long‐term, increased fire frequency can have negative effects on long‐term tree growth, but effects are contingent upon the fire return interval. These findings highlight important differences in how fire and thinning influence density‐dependent competition and the response of tree growth to climate. Although additional studies are needed from other forest ecosystems, this study provides early evidence that increased fire frequency will not alleviate drought stress and instead, may reduce long‐term, aboveground carbon storage in forests.

A conservation-oriented SNP panel for Smallmouth Bass (Micropterus dolomieu), with emphasis on Interior Highlands lineages

The Smallmouth Bass (Micropterus dolomieu; SMB) is a widely distributed black bass species, but the southwestern edge of the species range within the Interior Highlands contains some of the most divergent ecotypes. The Neosho subspecies (M. d. velox) inhabits tributaries of the Arkansas River within the Ozark Mountains and a second lineage is reported from drainages of the Ouachita Mountains. We sought to develop a single nucleotide polymorphism (SNP) panel to (1) diagnose hybridization with sympatric Spotted Bass (Micropterus punctulatus; SPB) and non-native Northern SMB (M. d. dolomieu) stocked in the region, and (2) delineate population structure within the ranges of the Neosho and Ouachita SMB lineages. We obtained 76 individual SMB samples from across their range but concentrated within the Interior Highlands (n = 50). We also included 3 SPB to allow for hybrid detection and 3 Shoal Bass (Micropterus cataractae) as an outgroup. Phylogenetic trees constructed with the generated SNP data corroborated the existence of at least three major lineages of SMB (Northern, Neosho, and Ouachita), each containing varying degrees of differentiation among major drainages. Simulation analyses revealed that chosen SNPs had high power (> 0.9) to assign SMB × SPB hybrid categories and similarly high power (> 0.8) for Northern SMB × Interior Highlands SMB hybrids. Clustering methods delineated major inter-basin population structure within the native ranges of Neosho and Ouachita SMB with chosen SNPs. Anticipated uses of the resulting 192-loci SNP panel include conservation planning, fisheries management assessments, and ecological investigations of the Neosho and Ouachita SMB lineages.

A History of the Ozarks: Vol. 1, The Old Ozarks. By Brooks Blevins

A History of the Ozarks: Vol. 1, The Old Ozarks. By Brooks Blevins

A History of the Ozarks: Vol. 2, The Conflicted Ozarks. By Brooks Blevins

A History of the Ozarks: Vol. 2, The Conflicted Ozarks. By Brooks Blevins

Paleotopography controls weathering of Cambrian-age profiles beneath the Great Unconformity, St. Francois Mountains, SE Missouri, U.S.A.

ABSTRACT Precambrian (1.4 to 1.5 Ga) granite and rhyolite in the St. Francois Mountains at the northeast corner of the Ozark Plateau in Missouri has been altered down to a depth up to 8 meters below the Great Unconformity (the contact between Paleozoic sedimentary rock and underlying Precambrian). Petrographic, geochemical, and mineralogic data indicate that at least two events generated this alteration: 1) surficial weathering due to subaerial exposure of the granite before Cambrian burial—this material is preserved as a paleosol; and 2) alteration due to reaction with basinal fluids channeled along the unconformity from nearby sedimentary basins long after burial by Paleozoic strata. To assess the variation between surficial weathering and basinal fluid alteration, we measured and sampled for petrologic, geochemical, and mineralogic data in the rock at and just below the Great Unconformity at three paleoelevations. Whole-rock geochemical oxide and X-ray diffraction data indicate that K-metasomatism and highly crystalline illite occurred in each profile. The K increase reflects crystallization of authigenic feldspar and illite from basinal fluids that were channeled along the Great Unconformity during younger Paleozoic fluid-flow events. Each profile also exhibits an upward increase in altered feldspar crystals and highly crystalline kaolinite, and an upward decrease in Ca and Na. Such changes reflect soil formation due to reaction with meteoric water before Cambrian burial, indicating that the altered granite was a paleosol before Paleozoic basinal fluid-flow events. Notably, the paleosol at the highest paleoelevation displays the least amount of paleoweathering and the paleosol at the lowest displays the greatest amount of paleoweathering. These results demonstrate that not only can characteristics of the paleosol just below the Great Unconformity be recognized in the St. Francois Mountains, despite subsequent alteration, but also it is possible to detect variations in soil thickness that were controlled by slope steepness and, therefore, water availability and/or soil creep or failure. This spatial relationship is compatible with studies of modern soils which indicate that soil character varies with position on a slope.

A History of the Ozarks, Volume 1: The Old Ozarks

A History of the Ozarks, Volume 1: The Old Ozarks

Assessing multi-scale habitat relationships and responses to forest management for cryptic and uncommon herpetofauna in the Missouri Ozarks, USA

Behaviorally cryptic or uncommon herpetofauna are often understudied due to the extensive effort it requires to obtain adequate data for statistical analysis. Additionally, potential impacts from forest management on these already small or difficult to study populations may have a dissimilar effect in comparison to more common species. To address this, we examined species-specific responses of uncommon herpetofauna within the Missouri Ozarks to even-aged and uneven-aged silvicultural systems at multiple scales, as well as their habitat relationships. Using capture histories collected over 23 years (1992–2014) on the Missouri Ozark Forest Ecosystem Project (MOFEP) we examined the cumulative effects of two harvest entries (1996 and 2011) at both the local- (stand-level) and landscape-scale (compartment-level) for eight uncommon herpetofauna, which includes one toad, two salamanders, one skink, and four snakes. We modeled capture probabilities with respect to multiple habitat- and harvest-related covariates. Three species showed compartment-level declines in the post-treatment period, however only two of the declines appeared to be related to forest management; the decline for the third species was observed in both treatment and control compartments suggesting that the cause was environmental related. In contrast to compartment-level responses, we observed stand-level responses in five species, mostly positive. In general, our observed declines were minimal and currently we have no concerns that forest management will lead to the loss of any of the uncommon herpetofauna species considered here. Our models showed habitat relationships for multiple species, which aids our understanding of species’ life history strategies and can also guide future management efforts.

Contrasting Ozark and Great Lakes populations in the endangered Hines emerald dragonfly (Somatochlora hineana) using ecological, genetic, and phylogeographic analyses

AbstractThe federally endangered species Hine's emerald dragonfly (Somatochlora hineana) is found in fens surrounding the Great Lakes region and in a small portion of the Missouri Ozarks. Most previous work has focused on the populations in the Great Lakes region. We present mark/recapture studies and genetic surveys to address the status of the Ozark populations. The densities and genetic diversity tend to be higher in the Ozarks than in the Great Lakes region. A phylogeographic analysis indicates that the Ozarks, with its unglaciated fens, is the likely source for the populations currently inhabiting the formerly glaciated Great Lakes region, and genetic diversity decreases with increasing distance from the Ozarks. This work illustrates the inadequacy of using geography alone to identify a population as marginal and of less conservation concern. We also reanalyzed genetic data on the Great Lakes populations, where several populations have been extirpated over the last several decades. We show that the populations in the Great Lakes region have already lost more than 30% of their genetic diversity over just several decades, and the phylogeographic analysis indicates that increased fragmentation is a possibility in this region due to local extirpations. Ecologically and genetically, the Ozark populations should have a high priority in management plans, and the high rate of loss of genetic diversity and potential fragmentation indicates that continued monitoring and management is needed in the Great Lakes region for this highly endangered dragonfly.

Integrating bioenergetics and conservation biology: thermal sensitivity of digestive performance in Eastern Collared Lizards (Crotaphytus collaris) may affect population persistence.

Information on bioenergetics can provide valuable insight into the ecology, life history and population dynamics of organisms. For ectothermic animals, thermal sensitivity of digestion is an important determinant of net assimilated energy budgets. A recent study in the Ozark Mountains indicated that eastern collared lizards (Crotaphytus collaris) restricted to encroached glades (characterized by woody vegetation encroachment) experience reduced environmental heat loads and have reduced age-specific growth and reproductive rates compared to populations in intact glades. To assess the potential impact of reduced body temperatures on assimilation rates of C. collaris in encroached glades, we conducted feeding trials across four temperature treatments (28, 31, 34 and 37°C). We tested for temperature effects on voluntary feeding rates, passage times, apparent assimilated energy (AE) and metabolizable energy (ME). Passage times decreased and voluntary feeding rates increased significantly with increasing temperature. Consumption explained the majority of variance in AE and ME, followed by the effect of temperature treatments. Using data on voluntary feeding rates, passage times and ME as a function of temperature, we estimated over a 10-fold increase in predicted daily assimilated energy across temperature treatments (28°C = 0.58 kJ/day, 31°C = 1.20 kJ/day, 34°C = 4.30 kJ/day, 37°C = 7.95 kJ/day). Thus, lower heat loads in encroached glades may cause reduced body temperature and result in restricted energy assimilation rates. Our study provides a novel approach to the integration of bioenergetics and conservation and shows the efficacy of using information on digestive performance to investigate underlying mechanisms in a conservation context.

<p><strong>Geographic variation in a restricted-range endemic dragonfly <em>Gomphurus</em> <em>ozarkensis</em> (Odonata: Gomphidae), with description of a new subspecies</strong></p>

The geographic distribution of Gomphurus ozarkensis (Westfall, 1975), a species described to science only four decades ago, is confined to a four-state area in the central United States: southeastern Kansas, eastern Oklahoma, western and northern Arkansas, and southern Missouri. Its small range has led some to classify it a species of conservation concern. We examined geographic variation in the species, which despite its small range exists in three distinct subpopulations: one in the Ouachita Mountains of western Arkansas and southeastern Oklahoma; one on the Ozark Plateau of northeastern Oklahoma, southeastern-most Kansas, southern Missouri, and northern Arkansas; and one in the Osage/Flint hills of southeastern Kansas and northeastern Oklahoma. Clinal variation is evident in the extent of yellow on the terminal abdominal segments and the extent to which certain thoracic stripes are fused. A population in a separate watershed basin in the southern Osage Hills of Oklahoma is taxonomically distinct, with some phenotypic characters tending toward G. externus (Hagen, 1858). We describe this population as a new subspecies of G. ozarkensis.

Review: Why Karen Carpenter Matters by Karen Tongson

Karen Tongson. Why Karen Carpenter Matters . Austin: University of Texas Press, 2019. 152 pp. I never cared about Karen Carpenter, not really. Sure, I've driven through the Missouri Ozarks with my older sister, both of us singing along to “Top of the World” and dreaming of life in California (

Smallmouth Bass Population Demographics in Missouri Ozark Streams and an Evaluation of a Statewide 305‐mm Minimum Length Limit

AbstractThe Ozark streams of Missouri provide anglers with unique Smallmouth Bass Micropterus dolomieu fishing opportunities. To ensure the sustainability and potential of these fisheries, we sampled five streams in the Ozark highland ecoregion of southern Missouri via recreational angling methods. From our samples, we developed estimates of recruitment, growth, and mortality, and assessed current regulations for Smallmouth Bass. To accomplish these objectives, we aged otoliths from 75 legal (305‐mm) fish on each stream. Back‐calculated length‐at‐age estimates were formed for sublegal lengths, and were paired with electrofishing length distributions on each stream using an age‐length key. These data were used to develop estimates of dynamic rate functions and models of yield, spawning potential, and number of memorable fish for each study population. We found that recruitment was stable on each stream, but growth and mortality varied among streams. We also found that models of yield, spawning potential, and number of memorable fish varied greatly among streams. Our results showed that the current 305‐mm statewide minimum length limit is applicable for some of our study streams, but yield, spawning potential, and trophy potential could increase with more restrictive length limits on some of our study streams. More spatially explicit length limits can help these Smallmouth Bass populations reach their growth potential. This information can help inform stream management in Missouri and across the Ozark region of the Midwest.