Litter Flammability of 50 Southeastern North American Tree Species: Evidence for Mesophication Gradients Across Multiple Ecosystems

Widespread fire exclusion and land-use activities across many southeastern United States forested ecosystems have resulted in altered species composition and structure. These changes in composition and structure have been implicated in positive fire-vegetation feedbacks termed “mesophication” where fire spread and intensity are diminished. In forests and woodlands, inherent flammability of different species is the mechanistic driver of mesophication. To date, there has been limited work on documenting the high diversity of flammability among species in the region, limiting the ability to differentiate among species to restore fuels that sustain fire regimes. Here, we coalesce disparate flammability data and add missing species across the spectrum from species that facilitate fire (so called “pyrophytes”) to those that dampen fire (so called “mesophytes”). We present data on 50 important tree species from across the southeast, all burned using identical laboratory methods. We divide our results for four dominant ecosystems: Coastal Plain uplands, oak-hickory woodlands, Appalachian forests, and bottomland forests. Across ecosystems, the most flammable species were American chestnut (Castanea dentata), a suite of pines (Pinus palustris, P. elliottii, P. serotina, and P. rigida), several oaks (Q. laevis, Q. falcata, Q. margaretta, and Q. alba), and sourwood (Oxydendrum arboreum). At the mesophytic end, the least flammable species were Tsuga canadensis, Acer rubrum, and several other hardwoods previously implicated in mesophication. Each of the four ecosystems we studied contained species that spanned the pyrophytic to mesophytic gradient. These data fill in some key holes in our understanding of southeastern fire adaptations, but also provide context for restoration decisions and fire management prioritization efforts to restore and sustain fire-prone ecosystems of the region.

The most southwestern locality and confirmed presence of Carabus (Carabus) vinctus (Weber, 1801) in Louisiana

New collection efforts led to re-discovery of Carabus (Carabus) vinctus (Weber) in Louisiana after the first record in 1874. The presumed range of the species in Louisiana is confined to the bottomland forests of the Lake Pontchartrain hydrological system including the lower flows of incoming streams. New locality extends the range of the species in the Gulf States almost 100 miles to the west and represents the most southwestern point of the whole range. Morphologically specimens from Louisiana are close to the Alabama specimens and belong to the var. georgiae Csiki.

Selection favors adaptive plasticity in a long-term reciprocal transplant experiment

Spatial and temporal environmental variation can favor the evolution of adaptive phenotypic plasticity, such that genotypes alter their phenotypes in response to local conditions to maintain fitness across heterogeneous landscapes. When individuals show greater fitness in one habitat than another, asymmetric migration can restrict adaptive responses to selection in the lower quality environment. In these cases, selection is predicted to favor traits that enhance fitness in the higher-quality source habitat at the expense of fitness in the marginal habitat, resulting in specialization to the high-quality environment. Here, we test whether plasticity is adaptive in a system regulated by demographic source-sink dynamics. Vaccinium elliottii (Ericaceae) occurs in dry upland and flood-prone bottomland forests throughout the southeastern United States, and shows patterns consistent with source-sink dynamics. We conducted a multi-year field experiment to evaluate whether plasticity in foliar morphology is advantageous. Both across habitats and within the high-quality upland environment, selection favored plasticity in specific leaf area and stomatal density. Stabilizing selection acted on plasticity in these traits, suggesting that extreme levels of plasticity are disadvantageous. We conclude that even in systems driven by source-sink dynamics, temporal and spatial variation in conditions can favor the evolution of plasticity.

Spatial variation in carotenoid plumage coloration and relationships between female coloration and quality in Prothonotary Warblers (Protonotaria citrea)

Many birds use conspicuous plumage coloration to signal quality for sexual or social selection. However, it is still often unclear how intraspecific coloration and associated signaling vary spatially. Plumage coloration that is dependent on carotenoids may be ideal for studying spatial color variation because birds cannot naturally synthesize this pigment; therefore, bird coloration from carotenoids is at least partially contingent upon diet. As food availability often varies spatially, so might color and its signaling strength. While male coloration has received more research focus, less is known about female coloration and its relationships with social rank or sexual quality. To further improve our understanding of spatial variation in plumage coloration and correlations with individual quality, we compared Prothonotary Warblers breeding at 2 ecologically disparate sites separated by 1,300 km: in bottomland forests of Arkansas, USA, and the forests near the tidal freshwater James River in Virginia, USA. We assessed crown and breast plumage coloration for both sexes and compared several color metrics between sites. We then assessed surrogates of female quality (number of young fledged, number of eggs laid, provisioning rate, apparent annual survival, and nest depredation) and compared coloration-quality relationships between sites. We found that coloration of birds breeding in Arkansas was generally more elaborate than those breeding in Virginia. However, this was somewhat dependent on sex: females showed greater differences than males between sites. Additionally, color metrics of females breeding in Virginia showed stronger relationships with quality (all 5 quality metrics) than for birds breeding in Arkansas (only provisioning rate and nest depredation). Proximately, spatial variation in plumage coloration and the associated signaling may be explained by differences in diet between sites. Ultimately, spatial variation in intra- and intersexual selection pressures may explain how spatial variation in plumage signal strength evolved.

Triclopyr Application Timing and Concentration Influence Low-Volume Basal Bark Efficacy on Chinese Privet (Ligustrum sinense)

Chinese privet is an invasive shrub that commonly infests roadsides and bottomland forests across the southeastern United States. Its aggressive growth and ability to prolifically sprout from the root collar and shallow lateral roots makes control very difficult. Individual plant treatment methods such as low-volume basal bark herbicide application with triclopyr are commonly used for Chinese privet control. However, little research has been done to examine optimal triclopyr concentrations and application timings for the low-volume basal bark method. Furthermore, little is known regarding basal bark treatment efficacy when plant size varies. To address these questions, field studies were conducted from 2009 to 2011 at two locations in east-central Alabama near Auburn and Opelika. The triclopyr butoxyethyl ester formulation was applied in January or March to Chinese privet shrubs across a range of sizes in a commercially available basal oil carrier at 24 (5% v/v−1), 48 (10% v/v−1), and 96 g L−1 (20% v/v−1). Additionally, a triclopyr butoxyethyl ester ready-to-use formulation (90 g L−1) was applied at 100% v/v−1. Canopy defoliation, sprout height, and mortality were quantified at 6, 12, and 18 mo after treatment. Triclopyr at all concentrations was highly effective in defoliating Chinese privet and reducing height of new basal sprouts. However, mortality was concentration dependent. The 90 and 96 g L−1 treatments resulted in 88 and 89% mortality across timings, while the 24 and 48 g L−1 treatments resulted in 63 and 76% mortality. March applications were less effective as basal diameter increased, especially at the lower triclopyr concentrations where mortality fell to less than 40%. These results indicate that triclopyr is an effective treatment for Chinese privet control, but efficacy is influenced by concentration, application timing, and plant size.

Rozsoshentsy forest area of Poltava-city green belt (soil-geobotanical and typological and characteristic)

Natural forests have their own ancient history, for this reason, their composition and structure reflect their existing conditions. In the artificial forests, only growth class and plantations general conditions can be in part the indicator of this residence. O. L. Belgard investigated natural biogeocoenosis and artificial cultural geocoenosis and worked up the detailed forest typology. The peculiarity of O. L. Belgard typology is biogeocoenological approach to the understanding and forest investigating based on G. M. Vysotskiy, G. F. Morozov, V. M. Suchkov ideas. O. L. Belgard accepted the conception of forest biogeocoenosis the components of which are phytocoenosis, zoocoenosis, microbiota, climatope and adaphotope. Rozsoshentsy forestry consists of 87 planning compartments with a total area of 3130.0 hectares, is a part of National Enterprise “Poltava forestry” and is situated on its southern part on the territory of Poltava administrative district and Poltava city. There are no publications in the science literature that could systematically reflect the results of investigations taken place in Rozsoshentsy forest area. Different scientists in different times investigated particular types of vegetations; the general characteristic of forests was specified in some works. The aim of our work is the forest typology investigation, ecological and biological, typological, soil and geobotanical peculiarities of natural and artificial forests of Rozsoshentsy forest area. For the fist time the investigation of natural and artificial forests of Rozsoshentsy forest area of Poltava-city green belt has been started according to the method of O. L. Belgard forest typology. Groups that were investigated inside the forestry are related to hydrotopes of bottomland forests with long-term flooding, bottomland forests with short-term flooding, noninundated with arena and ravine forests. The forest type is defined by accessories to specific trophotope and hydrotope and connected with floodplain factor of certain place of existence. The main place in definition of ecotope peculiarities takes vegetations that fully reflect the dimensionality of conditions. There are some plant associations inside the forest type that give an idea about coenosis from the floristic point of view. One or several associations can correspond to each forest type with direct species structure of tree, bushy and herbaceous layers. Artificial forests typological characteristic based on three taxonomic rank units: forest growth conditions type, ecological structure type and forest stand type. It was found out that the main forest types in structure of investigated forest area are oak, pine, sticky alder and aspen, poplar and birch forests. It means that main forest forming types are six types of wood. Rozsoshentsy forest area of Poltava-city green belt dendroflora has 33 tree and bushy types, 24 genuses, 14 families, 2 rooms. The most popular forest types on the investigated territory according to the forest typology are new oak and pine trees – 31.9 % , new pine forests – 9.1 %, new and dry maple and linden forests – 27.2 % and 6.3 % correspondently. Forest accounts for 5.3 % of forested areas with excessive wet ground. The investigation that was carried out gave us an opportunity to find out four natural forest vegetation types: (new linden and hornbeam forest with wide grasses), Dn4 (alder forest with moist tall grasses), Dc3 (wet aspen forest with aise-weed), De3 (wet white poplar forest); and two types of artificial forest vegetations: De3 (wet white poplar forest) and AB1 (birch forest with dryish miscellaneous). Different variations of soils have been investigated. It was found out that in investigated natural phytocoenosis the type of forest growth conditions is clay loam with different variations: new (СГ2), wet (СГ3), moist (СГ4); and wet sandy loam (СП3); in artificial cultural phytocoenosis the sandy loam is wet and dryish. The prevailing soil types on the territory of Rozsoshentsy forestry are dark grey podzolized forest loam, typical chernozem and podzolized hard loamy chernoozem, but in floodplain of the river Vorskla is a peat-bog soils. The content of humus is 7–8 %. The depth of ground water deposits connected with deposits of brown-red underclay (impermeable horizon) and ranges according to the relief elements and soil degree of erosion from 15 to 34 m. Carbonates are absent in soil of Rozsoshentsy forest area. Water extract analysis tells about the lack of salinity, dry particles ranges between 0.05–0.2 %, PH is mostly alkaline. Detailed ecological and biological characteristics and establishing peculiarities of Rozsoshentsy forest area adaphotope will give an opportunity to reconstruct the existing Poltava-city green belt plantations and organize the stationary investigations with the aim of their employment and saving.

Soil and geobotanical, typological characteristics of bottomland forest with short-term flooding Poltava-city green belt

Carrying out its assignment Poltava-city green belt bottomland forests with short-term flooding, has significant anthropogenic impact, needs constant research of forest biogeocoenosis present day condition. There have been done the complex research of bottomland forests with short-term flooding which are located in the range of Poltava-city green belt. Forest types according to O. L. Belgard have been noted. Soil and geobotanical characteristics, soil sections macromorphological peculiarities have been given, results of soil water extracts analysis in the investigated forestry have been noted. Throuout the complex researches of all components of forest biogeocoenosis the learning of forest and environment coorelation that is due to anthropogenic effect is topical. Especially it concerns the big cities green belt of industrial regions that suffer from the human direct influence or indirect consequences of his living. Thereby the National special-purpose program «Forests of Ukraine» for 2010–2015 was approved the aim of which is a complex study of this category of forest-steppe zone forest biogeocoenosis. For this reason was made an accent to investigate all-round the Poltava-city green belt forests related to Poltava Region throuout the regional special-purpose program of forestry integrated development «Poltava region forests by 2015». To identify the soil and geobotanical characteristics of biogeocenosis and physical and chemical piculiarities of bottomland forests with short-term flooding adaphotop we will consider the most typical sample plots of different plantations according to its forest stand that grows in relatively identical conditions. Forest areas of Poltava-city green belt belongs to the eastern soil and climatic forest-steppe zone of Poltava Region and is situated in forest-stepp belt of Left bank of Dnipro inside the Dnipro and Donetsk dimple. The most common soils are deep, low humic chernozem and middle clay-loam soil. There are mulch and sandy, agrilloarenaceous soils in river valleys. The picture of exploration area ground structure looks in such a way. The most common ground species of the area is a loess-like clay loam. There are sands observed near the river bed of Vorskla and clay on steep slopes. Soddy-meadow and chernozem-meadow, sandy loam and clay loam soils are involved in the bottomland forests formation. Typical chernozem occupies significant territories, which is formed by herbaceous grouping of mesoxerophytes, euxerophytes and xeromesophytes. Floodplain soils are divided into three parts: riverine, central and terrace near flood plain. In the riverine part is formed the most light mechanical components of interbedding soils formed on new derived silt from slightly humic layers. There are a low percent of humus (not more than 1 %) and nutritional chemicals. Thereby their fertility is low. In the central part of floodplain had been formed the sandy loam and clay loam soils with stronger profile on the massive, often calcareous or carbonaceous parent rock material. In cases of flood the water is widely overflowed and stay for a long time rich in sludge particles. It is the richest soils of the floodplain. The done research gave us the opportunity to clear up that the bottomland forests with short-term flooding of Poltava-city green belt are consist mainly of oak, aspen and alder forests. The formation and distribution of the main associations of floodplain forests depend on the regime of floodplain, trophotop and relief inhomogenuity. It was noticed that it can be found three more typical natural forest vegetations related to bottomland forests with short-term flooding inside the Poltava-city green belt: Dc' 3 (moist linden oak forest with hairlike sedge), Dn / 4 (alder forest with muddy tall herbaceous vegetation), Dc / 2 (live aspen forest with). It was noticed, that in all investigated plant formations the forest site type is sandy loam with different variations: live (SP / 2), moist (SP / 3), muddy (SP / 4). Different variations of soil has been investigated. There is no carbonate in soils of the investigated biogeocenosis. Water extract analysis tell about the lack of salinity properties, dry particles ranges (0,05–0,2 %), pH is alkaline. Detailed soil and geobotanical characteristics and establishing peculiarities of bottomland forests with short-term flooding adaphotop will give opportunity to reconstruct the existing Poltava-city green belt plantations and organize the stationary investigations with the aim of their more rational employment and saving.