Mesic Temperate Forests Research Articles

White Pine Restoration in a Mesic Forest: 3-year Results

Abstract Pinus strobus (Eastern White Pine) was an important component of mesic and dry-mesic northern temperate forests prior to European settlement. We evaluated the efficacy of restoration on a degraded, mesic hardwood site with a low post-harvest residual basal area (11.5 m2 ha-1). Three-year survival of planted pines was 57% (n = 299), with 40% mortality occurring the first year. Additional losses, however, were minimal: 2% and 1%) following years two and three, respectively. Survival was associated with presence of bare soil near the seedling (P < 0.05). High initial mortality was likely attributable to drought. Our results suggest that White Pine establishment on more mesic hardwood sites may be possible given sufficient soil and canopy disturbance, but that high initial mortality may be expected under dry climatic conditions.

Fossil beetles as possible evidence for transhumance during the middle and late Holocene in the high mountains of Talysch (Talesh) in NW Iran?

A short sediment core (300 cm) was retrieved from a peaty deposit in the northeastern corner of Lake Neor in NW Iran yielding a 6500-year-old sequence relatively rich in pollen and beetle remains. Beetle assemblages contained a significant amount of coprophagous and coprophilous species all along the core. Pollen spectra suggest an open steppe landscape typical of the modern Irano-Turanian highlands with pollen indicators of agro-pastoral activities and also the proximity of the mesic temperate Hyrcanian forest to the east. Together, insect and pollen evidence, in agreement with the archaeological evidence for NW Iran, suggest that pastoralism was practised in the high elevation surroundings of Neor in Talysch Mountains at least since ca. 6500 years ago. This preliminary study highlights the strong potential of palaeoentomological investigations in furthering our understanding of the history of pastoralism in the Middle East.

The short-term germination and establishment success of deer-dispersed seeds in mesic temperate forests1

Abstract White-tailed deer (Odocoileus virginianus, Zimmerman 1780) are known to disperse seeds through endozoochory, but the fates of these seeds are largely unknown. In both field and greenhouse studies, we examined the importance of fecal pellet decay to seed germination success and compared natural plant communities in microsites with and without deer pellets to determine the effects of deer endozoochory on short-term plant species composition. Pellets were collected in Delaware County, Ohio. After cold stratification, pellets were either crumbled or planted intact in the greenhouse to estimate numbers and species of viable seed present. These plantings produced germinants of 40+ taxa, 48% of which are non-native. Significantly more individuals germinated from crumbled than from intact pellets (P < 0.001), suggesting that pellet decay is crucial for germination success. In the field, feces deposited in the fall and spring decayed at rates that would allow seeds to escape the pellets in time for spring...

한국 미기록 귀화식물: 마늘냉이(십자화과)

ABSTRACT: Alliaria petiolata (M. Bieb.) Cavara & Grande (Brassicaceae) is an invasive species which is nativein Europe and SW Asia. This species is currently invading the understory of mature temperate forests of NorthAmerica. In Korea, A. petiolata is found to invade and colonize areas at forest margins along roadsides (Sam-cheok-si, Gangwon-do). This initial investigation serves to inform of the importance of early detection andextermination of this particular weed in Korea. Keywords: unrecorded plant, Brassicaceae, invasive plant, Alliaria 적요: 마늘냉이(Alliaria petiolata (M. Bieb.) Cavara & Grande)는유럽과 서남아시아 원산의십자화과 침입식물로서 현재 북미의 삼림 하부를 교란시키고 있는 것으로 알려져 있다. 이 종이 강원도 삼척시의 길가 숲을 따라 침입하여 우리나라에도 자라고 있는 것으로 확인되었다. 국내 확산을 막기 위한 기초 정보를 제공하기 위해 이 종에 대한 확인 결과를 보고하고자 한다. 주요어: 미기록식물, 십자화과, 침입식물, 마늘냉이속Brassicaceae (Cruciferae) are pantropical family with 338genera and ca. 3,700 species which is distributed worldwide(Al-Shehbaz et al., 2006). Most of the taxa are found intemperate regions of the northern hemisphere. According toKoch and Kiefer (2006), however, numerous genera are alsofound in the southern hemisphere (such as Draba, Lepidiumand Cardamine), and some genera are endemic in southernregions (South African genera: Heliophila, Silicularia,Brachycarpa, Chamira and Schlechteria). In South Korea,there are 29 genera with 77 species, including some introducedspecies (Oh, 2007). During a floristic survey of the eastern coastal area of SouthKorea, a specimen (Cho and Kim 120518-01, HHU) wascollected from Samcheok-si (Gangwon-do), and was identifiedas Alliaria petiolata (M. Bieb.) Cavara & Grande (Figs. 2, 3).Alliaria Heister ex Fabricius is comprised of two species nativein Europe and Southwestern Asia, and naturalized elsewhereas a cosmopolitan weed (Cheo et al., 2001a). A. petiolata isalso a biennial (and sometimes perennial) species which isdistributed within Morocco, the British Isles, north to northernScandinavia, east to northern India, and western China (Cheoet al., 2001a).Since the introduction of this weed to the United States asa culinary herb in the 1860s, A. petiolata has become one ofthe most problematic invaders of mesic temperate forests inNorth America, being the dominant understory species in*Author for correspondence: ydkim@hallym.ac.krhttp://www.pltaxa.or.krCopyright © 2012 the Korean Society of Plant Taxonomists

Edge‐related changes in tree communities in the understory of mesic temperate forest fragments of northern Japan

AbstractWe have assessed the effects of habitat fragmentation on understory tree communities in mesic temperate forests of the Tokachi plain of northern Japan. Tree community composition was analyzed across 13 forest fragments of various sizes ranging from 0.30 to 8.51 ha. The community composition varied along the edge‐to‐interior gradient: there was a lower abundance of shade‐tolerant shrubs in forest edges than in forest interiors, while saplings of dominant canopy trees and pioneer trees were more abundant near the edges. The edge influence extended approximately 56 m into the forest interiors. Even the interior area of small fragments were likely to be affected not only by the nearest edge but also by more distant edges. Consequently, most areas in fragments smaller than 2 ha were covered by these “edge‐type” communities. These results indicate that it is of primary importance to conserve and restore forests with an area at least larger than several hectares to sustain forest‐interior tree communities.

Post-Disturbance Plant Community Dynamics following a Rare Natural-Origin Fire in a Tsuga canadensis Forest

Opportunities to directly study infrequent forest disturbance events often lead to valuable information about vegetation dynamics. In mesic temperate forests of North America, stand-replacing crown fire occurs infrequently, with a return interval of 2000–3000 years. Rare chance events, however, may have profound impacts on the developmental trajectories of forest ecosystems. For example, it has been postulated that stand-replacing fire may have been an important factor in the establishment of eastern hemlock (Tsuga canadensis) stands in the northern Great Lakes region. Nevertheless, experimental evidence linking hemlock regeneration to non-anthropogenic fire is limited. To clarify this potential relationship, we monitored vegetation dynamics following a rare lightning-origin crown fire in a Wisconsin hemlock-hardwood forest. We also studied vegetation in bulldozer-created fire breaks and adjacent undisturbed forest. Our results indicate that hemlock establishment was rare in the burned area but moderately common in the scarified bulldozer lines compared to the reference area. Early-successional, non-arboreal species including Rubus spp., Vaccinium angustifolium, sedges (Carex spp.), grasses, Epilobium ciliatum, and Pteridium aquilinium were the most abundant post-fire species. Collectively, our results suggest that competing vegetation and moisture stress resulting from drought may reduce the efficacy of scarification treatments as well as the usefulness of fire for preparing a suitable seedbed for hemlock. The increasing prevalence of growing-season drought suggests that silvicultural strategies based on historic disturbance regimes may need to be reevaluated for mesic species.

Chloroplast evidence for geographic stasis of the Australian bird-dispersed shrub Tasmannia lanceolata (Winteraceae)

Few chloroplast-based genetic studies have been undertaken for plants of mesic temperate forests in the southern hemisphere and fossil-based models have provided evidence of vegetation history only at the broadest scales in this region. This study investigates the chloroplast DNA phylogeography of Tasmannia lanceolata (Winteraceae), a fleshy-fruited, bird-dispersed shrub that is widespread in the mountains of southeastern Australia and Tasmania. Thirty haplotypes were identified after sequencing 3206 bp of chloroplast DNA in each of 244 individuals collected across the species' range. These haplotypes showed unexpectedly strong phylogeographic structuring, including a phylogeographic break within a continuous part of the species' range, with the distribution of four major clades mostly not overlapping, and geographic structuring of haplotypes within these clades. This strong geographic patterning of chloroplast DNA provided evidence for the survival of T. lanceolata in multiple putative wet forest refugia as well as evidence for additional wet forest species refugia in southeastern Australia. In western Tasmania lower haplotype diversity below the LGM tree line compared to above the LGM tree line suggests that glacial refugia at high altitudes may have been important for T. lanceolata. The level of geographic structuring in T. lanceolata is similar to gravity dispersed southern hemisphere plants such as Nothofagus and Eucalyptus. Behavioural traits of the birds transporting seed may have had a strong bearing on the limited transport of T. lanceolata seed, although factors limiting establishment, possibly including selection, may also have been important.

Does moisture affect the partitioning of bryophytes between terrestrial and epiphytic substrates within cool temperate rain forests?

Bryophyte communities are highly sensitive to moisture and/or humidity levels. Most studies on the subject focus on bryophytes on either tree or ground habitats and do not consider how bryophytes partition themselves across both ground and epiphytic substrates within the same forest. Sampling mesic temperate forest sites of the same physiognomy from two Tasmanian regions with slightly different moisture levels (a wetter northwest versus a drier northeast region), we examine various aspects of the community structure (overall liverwort and moss cover; species richness; and liverwort to moss ratios) of both tree and ground communities with respects to moisture availability. We then test the hypothesis that a wetter site will exhibit a greater magnitude of bryophytes inhabiting both tree and ground habitats. Results of the analyses show that the ground habitat in the northwest sites exhibited a significantly higher mean species richness, higher overall and mean liverwort to moss ratio, and a higher liverwort cover than the northeast sites. This suggests that the northwest had a more ameliorated ground microclimate than the northeast. In terms of habitat partitioning, a significantly higher percentage of taxa occupied both tree and ground habitats in the northwest, compared to the northeast, which exhibited a higher percentage of taxa restricted to trees. It is proposed that within a single vegetation type, a higher site moisture level may create microclimates conducive to more bryophyte species in both tree and ground habitats, especially the latter, thereby enabling taxa to colonize and coexist on both substrates more freely.

Abiotic immobilization of nitrate in two soils of relic Abies pinsapo-fir forests under Mediterranean climate

Evidence for abiotic immobilization of nitrogen (N) in soil is accumulating, but remains controversial. Identifying the fate of N from atmospheric deposition is important for understanding the N cycle of forest ecosystems. We studied soils of two Abies pinsapo fir forests under Mediterranean climate seasonality in southern Spain—one with low N availability and the other with symptoms of N saturation. We hypothesized that biotic and abiotic immobilization of nitrate (NO3−) would be lower in soils under these forests compared to more mesic temperate forests, and that the N saturated stand would have the lowest rates of NO3− immobilization. Live and autoclaved soils were incubated with added 15NO3− (10 μg N g−1 dry soil; 99% enriched) for 24 h, and the label was recovered as total dissolved-N, NO3−, ammonium (NH4+), or dissolved organic-N (DON). To evaluate concerns about possible iron interference in analysis of NO3− concentrations, both flow injection analysis (FIA) and ion chromatography (IC) were applied to water extracts, soluble iron was measured in both water and salt extracts, and standard additions of NO3− to salt extracts were analyzed. Good agreement between FIA and IC analysis, low concentrations of soluble Fe, and 100% (±3%) recovery of NO3− standard additions all pointed to absence of an interference problem for NO3− quantification. On average, 85% of the added 15NO3− label was recovered as 15NO3−, which supports our hypothesis that rates of immobilization were generally low in these soils. A small amount (mean = 0.06 μg N g−1 dry soil) was recovered as 15NH4+ in live soils and none in sterilized soils. Mean recovery as DO15N ranged from 0.6 to 1.5 μg N g−1 dry soil, with no statistically significant effect of sterilization or soil type, indicating that this was an abiotic process that occurred at similar rates in both soils. These results demonstrate a detectable, but modest rate of abiotic immobilization of NO3− to DON, supporting our first hypothesis. These mineral soils may not have adequate carbon availability to support the regeneration of reducing microsites needed for high rates of NO3− reduction. Our second hypothesis regarding lower expected abiotic immobilization in soils from the N-saturated site was not supported. The rates of N deposition in this region may not be high enough to have swamped the capacity for soil NO3− immobilization, even in the stand showing some symptoms of N saturation. A growing body of evidence suggests that soil abiotic NO3− immobilization is common, but that rates are influenced by a combination of factors, including the presence of plentiful available carbon, reduced minerals in anaerobic microsites and adequate NO3− supply.

The effects of soil biota and fertilization on the success of Sapium sebiferum

Soil organisms can have important impacts on the structure, diversity, and invasion potential of plant communities. In particular, the short co-evolutionary history of non-native plants with soil biota could confer unusual benefits or costs to hosts in the introduced range with consequences for invasion success. We used parallel pot and field studies to examine how soil biota (active or sterilized soil) and fungicide (addition or control) affected the growth and survival of the invasive, non-native tree, Sapium sebiferum, and three co-occurring native tree species Liquidambar styraciflua, Nyssa sylvatica, and Quercus nigra in the Big Thicket National Preserve in east Texas, USA. In addition, because plant interactions with soil microbes vary with abiotic factors, we also included a fertilization treatment. The aboveground and belowground biomass of all species were higher in the presence of an active soil biotic community than in sterilized soil. Sapium alone showed more than additive growth increases under the combination of both field active and fertilized soils. It was also the only species to maintain high aboveground biomass and high aboveground nitrogen levels under those conditions. The high levels of arbuscular mycorrhizal colonization found on Sapium compared to natives suggest that arbuscular mycorrhizae may be involved in this phenomenon. These results indicate that belowground soil organisms provide unusual positive benefits to the invader that are not experienced by native species. This benefit may increase Sapium growth rates compared to natives in the forest understory and therefore facilitate Sapium invasion into mesic temperate forests currently experiencing high levels of anthropogenic nutrient inputs.

Effects of Pleistocene glaciations on population structure of North American chestnut‐backed chickadees

The postglacial recolonization of northern North America was heavily influenced by the Pleistocene glaciation. In the Pacific Northwest, there are two disjunct regions of mesic temperate forest, one coastal and the other interior. The chestnut-backed chickadee is one of the species associated with this distinctive ecosystem. Using seven microsatellite markers we found evidence of population structure among nine populations of chestnut-backed chickadees. High levels of allelic variation were found in each of the populations. Northern British Columbia and central Alaska populations contained a large number of private alleles compared to other populations, including those from unglaciated regions. The disjunct population in the interior was genetically distinct from the coastal population. Genetic and historical records indicate that the interior population originated from postglacial inland dispersal. Population structuring was found within the continuous coastal population, among which the peripheral populations, specifically those on the Queen Charlotte Islands and the central Alaska mainland, were genetically distinct. The pattern of population structure among contemporary chickadee populations is consistent with a pioneer model of recolonization. The persistence of genetic structure in western North American chestnut-backed chickadees may be aided by their sedentary behaviour, linear distribution, and dependence on cedar-hemlock forests.

The evolutionary ecology of masting: does the environmental prediction hypothesis also have a role in mesic temperate forests?

AbstractThe evolutionary advantages of mast seeding in mesic temperate forests are reviewed with reference to the whole plant's lifecycle. The aim of this article is to give attention to the environmental prediction hypothesis as an evolutionary aspect of closed‐forest dynamics that need to be tested in field studies and modelling. It is suggested that the year after a period of water stress (or other suboptimal conditions for growth) trees respond with high seed production. Due to an understory environment favorable for prolific establishment of seedlings (i.e., more light at the forest floor) this may give rise to a pulse of regeneration. Thus, understanding masting may require a multi‐faceted approach including the study of the ecology of the trees themselves beyond pollination and seed predation, and including gap ecology and patch dynamics with special attention to patterns of forest regeneration.

Differentiation Patterns of Reproductive Systems in the Genus Trillium

Abstract The differentiation patterns of reproductive systems, including breeding and pollination systems, and perennation strategies of the genus Trillium were critically studied. The pedicellate‐ and sessile‐flowered species with different floral morphologies and ecological distributions exhibited distinct modes of reproductive systems in relation to their habitat conditions. The pedicellate‐flowered species occurring in stable mesic temperate deciduous forests reproduce exclusively by seeds, while sessile‐flowered species growing in the alluvial flood plain habitats depend to a large extent on vegetative reproduction to compensate for the insufficient sexual reproduction under ecologically unstable conditions, e.g., frequent disturbance due to flooding. These sessile‐flowered species are characterized by low ovule numbers, subsequent low seed outputs and low fecundity levels. In contrast to the sessile‐flowered species, the pedicellate‐erect‐flowered species showed very high seed setting rates of over 50%. Breeding experiments for four Japanese species suggest that, although they substantially possess the capability of both inbreeding and outbreeding, the high fecundity levels are maintained by predominant inbreeding system. Furthermore, resource levels in the stock organs of these species obviously determine fecundity levels. As a consequence the amount of reserved food in the rhizomes transferred to the next season is determined, which gurantees a continuous reproductive activity of a given individual plant.

Nitrogen fixation in the lichen Lobaria pulmonaria in elevated atmospheric carbon dioxide.

Thalli of Lobaria pulmonaria (L.) Hoffm., a nitrogen-fixing epiphyte common in mesic temperate forests, were collected in a Douglas-fir (Pseudotsuga menziesii Franco) forest near Corvallis, Oregon, and maintained for 20 to 40 days in controlled-environment chambers with atmospheric CO2 concentrations of 374 and 700 μll-1. Nitrogenase activity, which was assayed by the acetylene reduction method, was approximately doubled in the lichen maintained in elevated CO2. Increases in nitrogen fixation by lichens may be an important part of the integrated ecosystem response to rising CO2.

Goshen Springs: Late Quaternary Vegetation Record for Southern Alabama

The sediments of Goshen Springs, Pike County, Alabama, USA, provide a late Quaternary biostratigraphic record that extends from the Altonial Substage of the Wisconsinan Glacial Stage to the present. Diagrams showing percentages of palynomorphs and concentrations of plant macrofossils permit the reconstruction of both local and regional vegetation. At Goshen Springs, a drying trend during the Altonian Substage (&gt;28 000 yr BP) resulted in the replacement of mesic—temperate forests by southern pines, oaks, and hickories. Climatic conditions of warmth and summer drought favored oak—hickory—southern pine forests from 26 000 yr BP in the mid—Farmdalian substage, through the full glacial and late glacial, until the mid—Holocene (5000 yr BP). During the full glacial, a strong climatic gradient and major vegetation ecotone extended across central Alabama and Georgia, separating northern boreal—like forests of spruce and jack pine from warm—temperate oak—hickory—southern pine forest on the Gulf Coastal Plain. The Goshen Springs record documents the persistence of many warm—temperate deciduous and broadleaf evergreen tree taxa in southern Alabama through the full and late glacial. The early Holocene forests, dominated by oak and hickory, were replaced by widespread southern pine forest on the sandy uplands of the Gulf Coastal Plain about 5000 yr ago. During the mid—Holocene, the attainment of the present climatic regime, characterized by abundant precipitation throughout the growing season, and the return of sea level to near—modern position resulted in the establishment of the southern pine forests and of widespread swamps and marshes in the Gulf and Southern Atlantic Coastal Plains.

THE COMPETITIVE RELATIONSHIP OF THREE WOODLAND SEDGES AND ITS BEARING ON THE EVOLUTION OF ANT-DISPERSAL OF CAREX PEDUNCULATA.

The dispersal of seeds by ants, myrmecochory, is a frequent feature among herbs from many families in mesic temperate forests. These ant-dispersed plants have a special fat body, the elaiosome, incorporated in each diaspore, the unit of dispersal. The elaiosome is food for the ants of many species, whose workers carry the seed + elaiosome unit to their nest, where the elaiosome is eaten and the seed discarded unharmed with other nest debris. The seed then germinates, often dispersed from the parent plant. This plant-ant relationship differs from activities of the true harvester ants which gather and eat the seeds themselves. Some seeds transported by harvester ants may accidentally escape predation and germinate (Cole, 1932; Tevis, 1958). This plantharvester ant interaction is not mediated by an elaiosome bait, involves a great loss of seed to the plant species during dispersal, and is quite different from the antdispersal of Carex pedunculata to be discussed here. The presence of ants as potential dispersal agents will not alone result in their dispersing seeds. Because enhanced dispersal, generally, is associated with early successional species or with poor competitive ability in both plants and animals, investigations of naturally competing species should contribute to an understanding of dispersal mechanisms. I report here the results of competition experiments among three woodland sedges in the genus Carex (Cyperaceae), of which C. pedunculata is ant-dispersed, and discuss the implications of these experiments for the life history of C. pedunculata and for the development and patterning of the forest herb stratum.