Upland Populations Research Articles

A re-consideration of the taxonomic status of Nebria lacustris Casey (Coleoptera, Carabidae, Nebriini) based on multiple datasets – a single species or a species complex?

This study gathered evidence from principal component analysis (PCA) of morphometric data and molecular analyses of nucleotide sequence data for four nuclear genes (28S, TpI, CAD1, and Wg) and two mitochondrial genes (COI and 16S), using parsimony, maximum likelihood, and Bayesian methods. This evidence was combined with morphological and chorological data to re-evaluate the taxonomic status of Nebria lacustris Casey sensu lato. PCA demonstrated that both body size and one conspicuous aspect of pronotal shape vary simultaneously with elevation, latitude, and longitude and served to distinguish populations from the southern Appalachian highlands, south of the French Broad, from all other populations. Molecular analyses revealed surprisingly low overall genetic diversity within Nebria lacustris sensu lato, with only 0.39% of 4605 bp varied in the concatenated dataset. Evaluation of patterns observed in morphological and genetic variation and distribution led to the following taxonomic conclusions: (1) Nebria lacustris Casey and Nebria bellorum Kavanaugh should be considered distinct species, which is a NEW STATUS for Nebria bellorum. (2) No other distinct taxonomic subunits could be distinguished with the evidence at hand, but samples from northeastern Iowa, in part of the region known as the “Driftless Zone”, have unique genetic markers for two genes that hint at descent from a local population surviving at least the last glacial advance. (3) No morphometric or molecular evidence supports taxonomic distinction between lowland populations on the shores of Lake Champlain and upland populations in the adjacent Green Mountains of Vermont, despite evident size and pronotal shape differences between many of their members.

The impact of distance and a shifting temperature gradient on genetic connectivity across a heterogeneous landscape

BackgroundInter-population distance and differences in breeding times are barriers to reproduction that can contribute to genotypic differentiation between populations. Temporal changes in environmental conditions and local selective processes can further contribute to the establishment of reproductive barriers. Telopea speciosissima (Proteaceae) is an excellent subject for studying the effect of geographic, edaphic and phenological heterogeneity on genotypic differentiation because previous studies show that these factors are correlated with morphological variation. Molecular, morphological and environmental datasets were combined to characterise the relative influence of these factors on inter-population differentiation, and Bayesian analyses were used to investigate current levels of admixture between differentiated genomes.ResultsA landscape genetic approach involving molecular and morphological analyses identified three endpoints of differentiated population groups: coastal, upland and southern. The southern populations, isolated from the other populations by an edaphic barrier, show low migration and no evidence of admixture with other populations. Amongst the northern populations, coastal and upland populations are connected along a skewed altitudinal gradient by genetically intermediate populations. The strong association between temperature and flowering time in Telopea speciosissima was shown to maintain a temporally unstable reproductive barrier between coastal and upland populations.ConclusionsSubstrate-mediated allopatry appears to be responsible for long-term genetic isolation of the southern populations. However, the temperature-dependent reproductive barrier between upland and coastal populations bears the genetic signature of temporal adjustments. The extreme climatic events of the last glacial maximum are likely to have caused more complete allochronic isolation between upland and coastal populations, as well as exerting increased selective pressure upon local genomes. However, at intermediate altitudes, current climatic conditions allow for the incorporation of alleles from previously distinct genomes, generating new, intermediate genomic assemblages and possibly increasing overall adaptive potential.

Distribution and Regional Ecology of Californian Palm Oases Interpreted from Google Earth Images

The native fan palms of the Baja California peninsula (Mexico) and neighboring southern California (USA) comprise two species each in Washingtonia and Brahea. While these are among the most familiar ornamental palms in the world, many features of their taxonomy, distribution, and environmental relationships remain unresolved. We utilized Google Earth Digital Globe imagery (and limited surveys by air and land) to develop the first map detailing the geographic distribution of palm populations in the Peninsular Range Province (PRP) and used these data to formulate new hypotheses on their biotic and abiotic relationships. We inventoried 15,216 populations covering an area of 8533 ha, containing an estimated 1.31 million trees. Tree populations estimated by manual tallies from Google Earth images closely matched direct counts published by previous workers. We documented significant extensions in the distributions of both Washingtonia species, as well as 66 hitherto unreported W. robusta oases in the Sierra La Asamblea. We also recorded thousands of upland populations of dwarf B. armata. Google Earth imagery shows that native fan palms are widespread in remote mountains of the entire peninsula, but in Baja California Sur W. robusta is mostly restricted to a few highly altered agricultural landscapes associated with extensive wetlands. It has long been assumed that the center of W. robusta distribution is in the tropical southern peninsula. Our observations suggest it may have been dispersed there by indigenous peoples before European contact, and its center of genetic diversity may instead lie in the Central Desert (ca. lat 28u–30uN).

Phenotypic plasticity despite source–sink population dynamics in a long‐lived perennial plant

• Species that exhibit adaptive plasticity alter their phenotypes in response to environmental conditions, thereby maximizing fitness in heterogeneous landscapes. However, under demographic source-sink dynamics, selection should favor traits that enhance fitness in the source habitat at the expense of fitness in the marginal habitat. Consistent with source-sink dynamics, the perennial blueberry, Vaccinium elliottii (Ericaceae), shows substantially higher fitness and population sizes in dry upland forests than in flood-prone bottomland forests, and asymmetrical gene flow occurs from upland populations into bottomland populations. Here, we examined whether this species expresses plasticity to these distinct environments despite source-sink dynamics. • We assessed phenotypic responses to a complex environmental gradient in the field and to water stress in the glasshouse. • Contrary to expectations, V. elliottii exhibited a high degree of plasticity in foliar and root traits (specific leaf area, carbon isotope ratios, foliar nitrogen content, root : shoot ratio, root porosity and root architecture). • We propose that plasticity can be maintained in source-sink systems if it is favored within the source habitat and/or a phylogenetic artifact that is not costly. Additionally, plasticity could be advantageous if habitat-based differences in fitness result from incipient niche expansion. Our results illuminate the importance of evaluating phenotypic traits and fitness components across heterogeneous landscapes.

Adaptations of skin peptide defences and possible response to the amphibian chytrid fungus in populations of Australian green‐eyed treefrogs, Litoria genimaculata

AbstractAim Rapidly evolving pathogens may exert diversifying selection on genes involved in host immune defence including those encoding antimicrobial peptides (AMPs). Amphibian skin peptides are one important defence against chytridiomycosis, an emerging infectious disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). We examined the population‐level variation in this innate immune defence to understand its relationship with disease dynamics.Location Queensland, Australia.Methods We examined skin peptide defences in five geographically distinct populations of Australian green‐eyed treefrogs, Litoria genimaculata. Skin peptide samples were collected from 52 frogs from three upland populations that previously declined as chytridiomycosis emerged, but subsequently recovered, and from 34 frogs in two lowland populations that did not decline. Historical samples of skin peptides preceding Bd emergence were not available from any population.Results In general, lowland populations had more effective peptide defences than upland populations. Peptide profiles were similar among populations, although relative amounts of peptides expressed differed significantly among populations and were more variable in the uplands. Infected frogs in upland populations carried a significantly higher infection burden compared to lowland populations. The presence of effective AMPs in the skin of L. genimaculata does not eliminate infection; however, more effective peptide defences may limit infection intensity and the progression of disease.Main conclusions The population bottleneck in upland populations caused by chytridiomycosis emergence did not appear to produce responses to selection for more effective peptide defences against chytridiomycosis compared to lowland populations of L. genimaculata. This does not exclude the possibility that current peptide defences have adapted in response to disease emergence. A suggestive (P < 0.10) interaction between infection status and population indicates that in lowland populations, infected individuals tend to be those with lower relative intensities of AMPs, whereas in the upland populations, infected and uninfected individuals are similar. Thus, both the AMPs and the environment may act to mediate resistance to Bd infection.

Subtle topographical differences along a floodplain promote different plant strategies among Paspalum dilatatum subspecies and populations

AbstractIt was hypothesised that subtle topographical differences might cause the existence of ecotypes along a floodplain. The apomict grass Paspalum dilatatum subspecies dilatatum inhabits flood‐prone lowlands as well as nearby uplands in the floodplains of Argentina, while the sexual P. dilatatum subspecies flavescens almost exclusively inhabits the uplands. The aim of the present study was to identify the different traits that allow these P. dilatatum populations to inhabit different habitats. Plants of P. dilatatum were reciprocally transplanted between uplands and lowlands. Morphophysiological traits related to flooding tolerance were measured during a flood. Subspecies dilatatum from the uplands and subspecies flavescens showed a high physiological performance in the uplands but a considerable decrease in stomatal conductance, net photosynthesis rates and tiller number in the flooded lowlands. In contrast, the subspecies dilatatum from the lowlands showed relatively lower and stable stomatal conductance, photosynthesis rates and leaf water potential at both sites. Subspecies dilatatum from the lowlands outperformed upland populations at the lowland site with respect to tillering. Leaves of subspecies dilatatum from the lowlands that had grown at the lowland habitat had a lower blade/sheath proportion than leaves of plants transplanted to the uplands. This behavior did not occur in both upland populations. Results suggest that dilatatum Lowland plants have the typical strategy of stress‐tolerant genotypes and that the upland populations are adapted to habitats where competitive species are selected. In conclusion, habitats with subtle differences in topographic level can favour both ecotypic differentiations within an apomict subspecies but also the maintenance of morphophysiological similitudes between coexisting upland populations belonging to different subspecies.

Genetic Diversity of Twelve Switchgrass Populations Using Molecular and Morphological Markers

Switchgrass (Panicum virgatum L.) is a warm season, C4 perennial grass native to most of North America with numerous applications, including use as a bioenergy feedstock species. To date, no studies on genetic diversity in switchgrass have been conducted that use both molecular and morphological markers. The objectives of this study were to assess genetic diversity and determine differences among and between 12 switchgrass populations grown in New Jersey by examining both morphological and molecular characteristics, and to determine whether morphological, molecular, and/or combined data sets can detect ecotype and/or geographical differences at the population level. Twelve plants from each population were characterized with 16 switchgrass expressed sequence tag-simple sequence repeat markers (EST-SSRs) and seven morphological characters. Data was analyzed using GenAlEx and Unweighted Pair-Group Method of Averages (UPGMA) cluster analysis. Most (64%) of the molecular variation in switchgrass populations exists among individuals within populations, with lesser amounts between populations (36%). Upland and lowland populations were distinguished in all three data sets. Some eastern US and midwestern US populations were distinct in all three data sets. Similarities were observed between all three data sets indicating molecular markers may be useful for identifying morphological differences or other adaptive traits. The combined data set was the most useful in differentiating populations based on geography and found separation between midwestern and eastern upland populations. The results indicate that the combination of morphological and molecular markers may be useful in future applications such as genetic diversity studies, plant variety protection, cultivar identification, and/or identifying geographic origin.

Elevation and habitats: the potential of sites at different altitudes to provide refuges for phytophagous insects during climatic fluctuations

Uplands are expected to provide refuges for species subject to lowland habitat loss and projected climate changes. Here, we argue that upland populations also provide refuges when lowland sites are subject to climatic fluctuations and extreme events and that species with populations dispersed over adjoining uplands and lowlands spread their risk of extinction. A proviso is that development is sufficiently lagged with altitude but that development rates are compatible. Emergence patterns and development of the butterfly Anthocharis cardamines and its larval host plant Cardamine pratensis show these characteristics, and coupled with the butterfly’s capacity to migrate between isolated populations present a case where upland and lowland populations can act as sources when one or the other area is adversely affected by extreme events.

Population genetic analysis of microsatellite variation of guppies (Poecilia reticulata) in Trinidad and Tobago: evidence for a dynamic source–sink metapopulation structure, founder events and population bottlenecks

Riverine fish populations are traditionally considered to be highly structured and subject to strong genetic drift. Here, we use microsatellites to analyse the population structure of the guppy (Poecilia reticulata), focussing on the headwater floodplain area of the Caroni drainage in Trinidad. We also analyse the population genetics of guppies in the Northern Drainage in Trinidad, a habitat characterized by rivers flowing directly into the sea, and a small isolated population in Tobago. Upland Caroni populations are highly differentiated and display low levels of genetic diversity. However, we found no evidence to suggest that these upland populations experienced recent population crashes and the populations appear to approach mutation-drift equilibrium. Dominant downstream migration over both short- and long-time frames has a strong impact on the population genetics of lowland Caroni populations. This drainage system could be considered a source-sink metapopulation, with the tributary furthest downstream representing a 'super sink', receiving immigrants from rivers upstream in the drainage. Moreover, the effective population size in the lowlands is surprisingly low in comparison with the apparently large census population sizes.

Adaptive strategies to tolerate prolonged flooding in seedlings of floodplain and upland populations of Himatanthus sucuuba, a Central Amazon tree

Long-term flooding imposes a strong selection pressure on plants for the development of protective mechanisms to alleviate the harmful effects of hypoxic and anoxic conditions. This is particularly critical in the Amazonian floodplains where plants withstand annual periods of flooding lasting 7 months and mean flooding amplitude reaching 10 m or more. Himatanthus sucuuba (Apocynaceae) is a tree that is found in the varzea (VZ) floodplains and non-flooded terra firme (TF) forests. It was examined whether individuals from these two contrasting habitats respond differently when subjected to extreme flooding conditions. TF and VZ seedlings were experimentally well-watered, waterlogged (roots and parts of the stems flooded), or submerged (whole plant flooded) during a 4-month period. Anaerobic respiration, evaluated by measuring alcohol dehydrogenase (ADH) activity, and root carbohydrate reserves were quantified, given that the availability of readily fermentable carbohydrates is essential to sustain an active fermentative metabolism. We also assessed changes in morphoanatomy, seedling survival, biomass accumulation and distribution. VZ seedlings had greater root concentrations of soluble sugars and starch, larger seedling mass and accumulated more biomass in roots and stems while TF seedlings allocated more towards stem and leaves. ADH activity was low in seedlings of both populations before exposure to flooding. Waterlogging induced an increase in ADH activity that reached a maximum value in 15 days. Thereafter activity decreased slowly, meanwhile a rapid formation of lenticels, adventitious roots and aerenchyma was observed. Submergence induced leaf shedding and the development of aerenchyma in the root cortex. While VZ seedlings maintained high levels of ADH activity throughout the whole 4-month period, ADH activity in TF seedlings peaked about 15 days after submersion followed by a continuous decrease and death of all the plants. Thus, VZ and TF seedlings differed considerably in terms of tolerating long-term exposure to flooding, especially under total submersion. These results suggest that the predictability and long-term duration of flooding in Central Amazon rivers can impose a selective pressure that is strong enough to result in large phenotypic differences between the two populations of H. sucuuba in the two habitat types.

HIGHLANDERS ON THE HO CHI MINH TRAIL

The history of the hinterlands of the Indochinese peninsula, astride the frontier between Laos and Vietnam, during the first and second Indochina wars (1946–75) is arguably the least informed of this turbulent period. The aftermath of World War II saw the establishment of revolutionary bases at the junction between southeastern Laos and central and southern central Vietnam in highly strategic areas that were conduits for the “Ho Chi Minh Trail.” This article aims to go beyond conventional diplomatic and military histories of the Indochina wars to examine war from below. In particular, the second half of the article is constructed around the narratives of two female war veterans of ethnic minority origins who conducted most of their revolutionary activities during the Vietnam War along the Ho Chi Minh Trail. Particular attention is given to their motivations and wartime lives, linked to their transformation from members of upland populations who not long ago were described as “savages” into “revolutionaries” and “patriots.”

Heterosis in Switchgrass: Spaced Plants

Population and specific hybrids were made between populations and genotypes of switchgrass, Panicum virgatum L., and their progeny were evaluated for heterosis in space‐transplanted field trials in eastern Nebraska for a 3‐yr period. ‘Kanlow’ (lowland tetraploid) × ‘Summer’ (upland tetraploid) hybrids exhibit midparent heterosis for second‐ and third‐year biomass yields for both population and individual plant hybrids. These data and previously reported molecular marker data indicate that lowland‐tetraploid and upland‐tetraploid switchgrasses represent different heterotic groups that can potentially be used to produce F1 hybrid cultivars. Hybrids produced from cultivars and experimental strains developed from upland‐octaploid germplasm originating from spatially separated western and eastern regions of the original tallgrass or an adjacent forested ecoregion did not exhibit heterosis for any trait evaluated. These results suggest that these upland populations evaluated were from the same or closely related large germplasm pools or heterotic groups. A method for developing F1 switchgrass hybrid cultivars utilizing the gametophytic self‐incompatibility mechanism of the species is described.

Flooding tolerance of Paspalum dilatatum (Poaceae: Paniceae) from upland and lowland positions in a natural grassland

The grass Paspalum dilatatum Poir. subsp. dilatatum inhabits periodically flooded lowlands as well as non-flooded uplands of the flooding Pampa grasslands (Argentina), while P. dilatatum Poir. subsp. flavescens Roseng., B.R. Arrill. & Izag. inhabits only the upland sites. An experiment was designed to determine if there is local adaptation to flooding in physiological, anatomical and leaf morphological traits. To this end, plants of these populations were subjected to flooding (6 cm water depth) and control conditions (watered daily) for 60 days in an experimental garden. Flooded plants of the subsp. dilatatum from the lowland had 35% higher photosynthesis compared to controls without affecting their stomatal conductance, transpiration rate and leaf water potential. By contrast, both subsp. dilatatum and subsp. flavescens from the upland did not increase their photosynthesis, and had reduced their stomatal conductance and leaf transpiration rate by 35% and 45% when growing in flooded conditions. Upland populations had higher leaf water potential with respect to controls. All populations had high constitutive root aerenchyma (28–42%), and leaf sheath porosity increased by 75% in flooded conditions (from 22–28% to 35–48%). Leaf lengthening differed among populations according to their habitat: subsp. dilatatum from the lowland was the only one that had longer leaf sheaths and blade lengths when flooded. In contrast, flooded plants of subsp. dilatatum from the upland only increased leaf sheath length while subsp. flavescens neither increased leaf blade nor leaf sheath. In conclusion, both the physiological performance and the leaf length plasticity differed among populations. The results agree with those expected based on the species’ habitat, and indicate the better adaptation to the flood-prone habitat of P. dilatatum subsp. dilatatum taken from a lowland area.

Differential Growth and Rooting of Upland and Peatland Black Spruce, Picea mariana, in Drained and Flooded Soils

AbstractA reciprocal experiment was analyzed to determine whether 30 open-pollinated families of peatland and upland populations of black spruce [Picea mariana (Mill.) B.S.P.] sampled from a single area in north-central Alberta, Canada, performed consistently when grown in either flooded or well-drained soils (i.e., if there is a family x soil interaction or generally called genotype x environment interaction (GEI)). The data for the analysis consisted of five traits (height, root dry weight, shoot dry weight, root/shoot dry weight ratio and number of braches) describing growth and rooting performance of tree seedlings in flooded and drained soils (root environments) in a greenhouse for 16 weeks. A mixed-model analysis was used to characterize GEI. The analysis revealed an interesting contrast of GEI patterns between the peatland vs. upland populations: GEI was absent (as indicated by a perfect correlation between flooded and drained soils) in peatland population but present in the upland population. Our results from the characterization of GEI are also consistent with the well-known theory about selection in different environments that correlated responses due to indirect selection are in general less than direct responses. The contrasting patterns of GEI in peatland vs. upland populations may be reflective of different strategies of adaptation to the contrasting environmental conditions, with the peatland trees growing slowly but steadily and with the upland populations growing fast and very responsive to environmental changes.

Estimation of genetic variability and heritability for biofuel feedstock yield in several populations of switchgrass

AbstractInformation on heritability and predicted gains from selection for increased biomass yield for ethanol production in switchgrass is limited and may vary among breeding populations. The purpose of this study was to estimate heritability and predicted gains from selection for higher biomass yield within a lowland ecotype switchgrass population, Southern Lowland 93 (SL‐93), and two upland ecotype switchgrass populations, Southern Upland Northern Upland Early Maturing (SNU‐EM) and Southern Upland Northern Upland Late Maturing (SNU‐LM). Narrow‐sense heritabilities (hn2) for biomass yield in each of the three populations were estimated via progeny–parent regression analysis. Half‐sib (HS) progeny families from 130 randomly selected plants from the SL‐93 population were evaluated for biomass yield in replicated trials in 2002 and 2003. Clonal parent plants were evaluated for biomass yield in separate environments to provide unbiased hn2 estimates from progeny–parent regression. Yield differences were highly significant among SL‐93 HS progenies within and over years. For the SL‐93 population, hn2 estimates were 0.13 and 0.12 based on individual plant and phenotypic family mean (PFM) selection, respectively. Predicted genetic gains (ΔG) per selection cycle were 0.15 kg dry matter (dm) plant−1 and 0.10 kg dm plant−1 for PFM and individual plant selection methods, respectively. For the SNU‐EM and SNU‐LM populations, year and year × HS family effects were highly significant (P < 0.01) and the HS family effect over years was nonsignificant (P < 0.05). However, HS family effects were highly significant within respective years (P < 0.01). Estimates of hn2 for the SNU‐EM and SNU‐LM populations based on PFM and individual plant selection were similar, ranging from 0.44 to 0.47; ΔG per selection cycle ranged from 0.22 to 0.33 kg dm plant−1. The magnitudes of the estimates of additive genetic variation suggest that selection for higher biomass yield should be possible. The substantial effect of environment on biomass yields in the upland populations and the failure of families to respond similarly over years stress the importance of adequately testing biomass yield over years to assess yield.

Floodplain and upland populations of Amazonian Himatanthus sucuuba: Effects of flooding on germination, seedling growth and mortality

Himatanthus sucuuba is a tree species that occurs in Central Amazonian white water floodplains and in non-flooded uplands. The objective of this paper was to verify whether flooding causes differences in germination percentages, seedling mortality as well as alterations of leaf number and biomass increments, related to the habitat of origin of the seeds (várzea floodplain versus terra firme upland, in the following V and TF, respectively). To test this effect, seeds from populations of both habitats were collected, and germination percentages were calculated under different experimental conditions. One hundred seeds collected in three sites of the floodplain and one hundred seeds from three sites of the upland were placed in trays for germination in a greenhouse in the Amazon Research Institute (INPA) in Manaus, Brazil. Seedlings with a height of 7 cm were then subjected to a period of 120 days of flooding in tanks with three treatments: control, waterlogging (root system and the base of the stem), and complete submersion. Ground water from the INPA was used in the tanks and was changed at weekly intervals. Germination percentages were high in most treatments. Seedling mortality was significantly higher in seedlings originating from upland, reaching 100% in submerged seedlings. On the other hand, várzea-originated seedlings showed no mortality under waterlogging or submergence. Height growth of waterlogged seedlings from floodplains exceeded that of the control. Submerged seedlings did not grow, independently of the origin, and those originating from uplands died after about 100 days. Number of leaves and leaf area were significantly lower under partial submersion than in the control, independently of the origin of the seeds. Under total submersion abscission of all leaves was verified 30 days after inundation for seedlings of both origins. In the V population, all seedlings survived the waterlogged period, whereas in the TF population, 30% of the seedlings died when subjected to waterlogging. With complete submergence, in the V population 30% of the seedlings had died after 120 days, in the TF population after 90 days mortality was 100%. The results show that germination, seedling growth and seedling survival in H. sucuuba differ among populations of floodplain and upland sites: V plants performed better than TF plants under waterlogging and under submersion. The results strongly indicate that ecotypic differentiation exists between these two populations of H. sucuuba individuals in the two habitat types, which may be enforced by a strong selective pressure due to the regular occurring flood pulse.

Divergent selection as revealed byPSTand QTL‐basedFSTin three‐spined stickleback (Gasterosteus aculeatus) populations along a coastal‐inland gradient

Three measures of divergence, estimated at nine putatively neutral microsatellite markers, 14 quantitative traits, and seven quantitative trait loci (QTL) were compared in eight populations of the three-spined stickleback (Gasterosteus aculeatus L.) living in the Scheldt river basin (Belgium). Lowland estuarine and polder populations were polymorphic for the number of lateral plates, whereas upland freshwater populations were low-plated. The number of short gill rakers and the length of dorsal and pelvic spines gradually declined along a coastal-inland gradient. Plate number, short gill rakers and spine length showed moderate to strong signals of divergent selection between lowland and upland populations in comparison between P(ST) (a phenotypic alternative for Q(ST)) and neutral F(ST). However, such comparisons rely on the unrealistic assumption that phenotypic variance equals additive genetic variance, and that nonadditive genetic effects and environmental effects can be minimized. In order to verify this assumption and to confirm the phenotypic signals of divergence, we tested for divergent selection at the underlying QTL. For plate number, strong genetic evidence for divergent selection between lowland and upland populations was obtained based on an intron marker of the Eda gene, of which the genotype was highly congruent with plate morph. Genetic evidence for divergent selection on short gill rakers was limited to some population pairs where F(ST) at only one of two QTL was detected as an outlier, although F(ST) at both loci correlated significantly with P(ST). No genetic confirmation was obtained for divergent selection on dorsal spine length, as no outlier F(ST)s were detected at dorsal spine QTL, and no significant correlations with P(ST) were observed.

First results on the feeding ecology of the Transcaucasian water shrew Neomys teres (Soricomorpha: Soricidae) from Armenia

Microscopic examination of alimentary tracts of 14 Neomys teres Miller, 1908 from a mountainous region in northern Armenia produced the first data on the diet of this almost unknown species of conservation concern. Twenty-three different prey types were distinguished in summer-caught shrews, all of which were invertebrates (14 terrestrial and 9 aquatic in origin). The dominant dietary items were Coleoptera and Diptera adults, Araneae, Opiliones, and Lumbricidae, as well as freshwater crustaceans and Trichoptera larvae. Prey ranged from <3 to >16 mm in length, but those eaten most frequently were 6–10 mm in length. Although N. teres was captured beside streams and rivers, aquatic prey comprised only 27% of the dietary composition. Despite the morphological similarity of N. teres to Neomys fodiens (Pennant, 1771), its foraging niche more closely resembles that of upland populations of Neomys anomalus Cabrera, 1907 and its reliance on aquatic habitats remains equivocal.

Fine scale gene flow and individual movements among subpopulations of Centrolene prosoblepon (Anura: Centrolenidae)

Dispersal capabilities determine and maintain local gene flow, and this has implications for population persistence and/or recolonization following environmental perturbations (natural or anthropogenic), disease outbreaks, or other demographic collapses. To predict recolonization and understand dispersal capacity in a stream-breeding frog, we examined individual movement patterns and gene flow among four subpopulations of the Neotropical glassfrog, Centrolene prosoblepon, at a mid-elevation cloud forest site at El Copé, Panama. We measured male movement directly during a two year mark-recapture study, and indirectly with gene flow estimates from mitochondrial DNA sequences (mtDNA). Individuals of this species showed strong site fidelity: over two years, male frogs in all four headwater streams moved very little (mean = 2.33 m; mode = 0 m). Nine individuals changed streams within one or two years, moving 675-1,108 m. For those males moving more than 10 m, movement was biased upstream (p < 0.001). Using mtDNA ND1 gene sequences, we quantified gene flow within and among headwater streams at two spatial scales: among headwater streams within two adjacent watersheds (2.5 km2) and among streams within a longitudinal gradient covering 5.0 km2. We found high gene flow among headwater streams (phi(ST) = 0.007, p = 0.325) but gene flow was more limited across greater distances (phi(CT) = 0.322, p = 0.065), even within the same drainage network. Lowland populations of C. prosoblepon potentially act as an important source of colonists for upland populations in this watershed.

Layers of Loyalty: Confederate Nationalism and Amnesty Letters from Western North Carolina

In November 1863, North Carolina governor Zebulon B. Vance reported to a correspondent that there was "an astonishing amount of disloyalty" to the Confederacy in the mountain counties of western North Carolina.1 Problems related to conscription and desertion led Robert E. Lee, Jefferson Davis, and other Confederate leaders to reach the same conclusion. Two months later, Vance, a native of western North Carolina, wrote to former North Carolina governor David L. Swain, another western North Carolinian, offering a brief comparison between the patriots of the War for Independence and Southerners during the present conflict. He concluded: "Liberty and independence can only be gathered of blood and misery sustained and fostered by devoted patriotism and heroic manhood. This requires a deep hold on the popular heart, and our people will not pay this price."2 After Hood's defeats around Atlanta in the summer of 1864, Vance wrote to Swain again and observed that "the great popular heart is not now and never has been in the war. It was a revolution of the politicians; not the people."3 Thus, the most acute political observer of western North Carolina during the war started part of the great debate about the commitment of Confederates to their new nation. [End Page 5] Modern historians have access to much more written documentation than Vance did when he made his assessments. Essays by Gary W. Gallagher, Drew Gilpin Faust, and Benjamin L. Carp explore the same themes that Vance did and have come to profoundly different conclusions about the nature of Confederate nationalism. They point out the significant and consistent support that the Confederacy enjoyed among the white population of the eleven states of the attempted new nation. Recognizing that some areas of the South were dominated by the opponents of the proposed Southern nation—eastern Tennessee and northwestern Virginia, in particular—they still maintain that a real and substantial Confederate nationalism existed between 1861 and 1865.4 Other scholars, including Paul Escott, William W. Freehling, and Richard E. Beringer and his colleagues, have concluded with Vance that popular support for the Confederacy was never robust and was eroded by the obtuseness of the Richmond government and military defeat.5 While the two schools of scholars appear to disagree considerably, they do share substantial areas of agreement as well. All would agree that white Southerners felt threatened by political and ideological developments that took shape in the nonslave states after 1830. They would also agree that there appeared to be substantial enthusiasm for the Confederate cause after Lincoln's call for troops in April 1861. All these scholars would undoubtedly agree that without the adoption of conscription in April 1862 and unpopular taxing policies, the Davis administration could not have sustained the new government for as long as it did. None of the later observers would dissent from the idea that many Southerners had a strong—and perhaps primary—loyalty to family, neighborhood, and state. Nor is there any real dispute that the Confederate leadership, including Lee, Davis, and Vance, was convinced that desertion seriously weakened the war effort. The differences that the scholars claim to see in the viability of Confederate nationalism come more from disagreements about the significance and meaning of these factors than the events and commitments themselves. [End Page 6] For one group of historians, however, Vance's assertions have a strong resonance. These are the scholars who have concentrated their attention on the mountain South—the area that Vance understood best. Daniel Crofts and William Freehling have amply documented that the people in the highlands, along with others in the upper South, were reluctant Confederates.6 Some mountain residents such as Andrew Johnson, William G. Brownlow, and the founders of the state of West Virginia were outspoken unionists who refused to accept the idea of a separate Southern nation.7 Other upland populations in southern Missouri and eastern Kentucky were active parts...