Forest Shrubs Research Articles

Removal of invasive shrubs alters light but not leaf litter inputs in a deciduous forest understory

The establishment and spread of non‐native, invasive shrubs in forests poses an important obstacle to natural resource conservation and management. This study assesses the impacts of the physical removal of a complex of woody invasive shrub species on deciduous forest understory resources. We compared leaf litter quantity and quality and understory light transmittance in five pairs of invaded and removal plots in an oak‐dominated suburban mature forest. Removal plots were cleared of all non‐native invasive shrubs. The invasive shrubs were abundant (143,456 stems/ha) and diverse, dominated by species in the genera Ligustrum, Viburnum, Lonicera, and Euonymus. Annual leaf litter biomass and carbon inputs of invaded plots were not different from removal plots due to low leaf litter biomass of invasive shrubs. Invasive shrub litter had higher nitrogen (N) concentrations than native species; however, low biomass of invasive litter led to low N inputs by litter of invasive species compared to native. Light transmittance at the forest floor and at 2 m was lower in invaded plots than in removal plots. We conclude that the removal of the abundant invasive shrubs from a native deciduous forest understory did not alter litter quantity or N inputs, one measure of litter quality, and increased forest understory light availability. More light in the forest understory could facilitate the restoration of forest understory dynamics.

Neighborhood structure influences the convergence in light capture efficiency and carbon gain: an architectural approach for cloud forest shrubs.

Although plant competition is recognized as a fundamental factor that limits survival and species coexistence, its relative importance on light capture efficiency and carbon gain is not well understood. Here, we propose a new framework to explain the effects of neighborhood structures and light availability on plant attributes and their effect on plant performance in two understory shade-tolerant species (Palicourea padifolia (Roem. & Schult.) C.M. Taylor & Lorence and Psychotria elata (Swartz)) within two successional stages of a cloud forest in Costa Rica. Features of plant neighborhood physical structure and light availability, estimated by hemispherical photographs, were used to characterize the plant competition. Plant architecture, leaf attributes and gas exchange parameters extracted from the light-response curve were used as functional plant attributes, while an index of light capture efficiency (silhouette to total area ratio, averaged over all viewing angles, STAR) and carbon gain were used as indicators of plant performance. This framework is based in a partial least square Path model, which suggests that changes in plant performance in both species were affected in two ways: (i) increasing size and decreasing distance of neighbors cause changes in plant architecture (higher crown density and greater leaf dispersion), which contribute to lower STAR and subsequently lower carbon gain; and (ii) reductions in light availability caused by the neighbors also decrease plant carbon gain. The effect of neighbors on STAR and carbon gain were similar for the two forests sites, which were at different stages of succession, suggesting that the architectural changes of the two understory species reflect functional convergence in response to plant competition. Because STAR and carbon gain are variables that depend on multiple plant attributes and environmental characteristics, we suggest that changes in these features can be used as a whole-plant response approach to detect environmental filtering in highly diverse tropical forest communities.

Assessment of Ecosystem Water Conservation Value In The Beijing Four Seasons Flower Valley

Based on the data of field investigation and multi-source data analysis, Beijing Four Seasons Flower Valley declared in 2008 towards valley economy water conservation function and value was estimated by means of rainfall storage capacity as well as ecological economy. The results showed that: Landscape structure of FSFV was forest land-cultivated land-grassland. FSFV had the highest water conservation function in Beijing valleys, with the capacity of 1101.13 m3/hm2. Annual total amount of water conservation was 31.20×106 m3, accounting for 10.07% of Beijing valleys, and the total value of water conservation was 3.61×108 Yuan. High water conservation capacity areas were mainly located in the eastern mountainous region with broadleaf forest centralized distribution. Low water conservation function areas were mainly occurred in the regions effected by human activities. Forest ecosystem had the highest capacity of water conservation of 1116 m3/hm2, while construction ecosystem had the lowest. Higher degree of human activities, lower capacity of water conservation. Shrub forest and broadleaf forest had the largest contribution on valley water conservation, with contribution rate of 36.35% and 35.62%. Ranking of water conservation capacity, broadleaf forest had the highest value of 1135 m3/hm2, followed by coniferous forest, shrub forest and mixed forest.

A decrease in heat insulation of the black-clawed brush-furred rat (Lophuromys melanonyx, Petter) during adaptation to high altitudes.

The results of the body-surface infrared thermography of rodents of the genus Lophuromys suggest that heat insulation of the black-clawed brush-furred rat L. melanonyx, a large specialized species of the AfroAlpine zone, is worse than that of the related smaller species, the golden-footed (L. chrysopus) and shorttailed (L. brevicaudus) brush-furred rats, that inhabit tropical forest and Erica shrub, respectively. A decrease in heat insulation of the alpine species may facilitate the use of solar radiation for supporting heat balance of these diurnal animals.

Which leaf mechanical traits correlate with insect herbivory among feeding guilds?

There is abundant evidence that leaf mechanical traits deter feeding by insect herbivores, but little is known about which particular traits contribute to defence across feeding guilds. We investigated the contribution of multiple mechanical traits from shear, punch and tear tests to herbivore deterrence across feeding guilds. Visible damage from miners and external chewers was measured and sucker feeding density estimated in mature leaves of 20 species of forest shrubs and small trees. Cafeteria trials were undertaken using a generalist chewer (larvae of Epiphyas postvittana, Lepidoptera). Damage was compared with leaf mechanical traits and associated nutrient and chemical defence traits. Damage by external chewers in the field and by E. postvittana correlated negatively with mechanical traits. Hierarchical partitioning analysis indicated that the strongest independent contribution to chewing damage was by the material trait of specific work to shear, with 68 % of total variance explained by the combination of specific work to shear (alone explaining 54 %) and tannin activity in a regression model. Mining damage did not correlate with mechanical traits, probably because miners can avoid tissues that generate high strength and toughness in mature leaves. Mechanical traits correlated more strongly with chewing damage in the field than chemical defences (total phenolics and tannin activity) and nutrients (nitrogen and water), but nutrients correlated strongly with diet selection in the cafeteria trial. Surprisingly, sucker feeding density correlated positively with mechanical traits and negatively with nutrients. Mechanical traits of mature leaves influenced insect feeding guilds differentially, reflecting differences in life history and feeding modes. For external chewers, energy (work) to fracture in shearing tests, at both structural and material levels, was strongly predictive of damage. Knowing which leaf mechanical traits influence insect feeding, and in which guilds, is important to our wider understanding of plant-herbivore interactions.

Wall-to-Wall Forest Mapping Based on Digital Surface Models from Image-Based Point Clouds and a NFI Forest Definition

Forest mapping is an important source of information for assessing woodland resources and a key issue for any National Forest Inventory (NFI). In the present study, a detailed wall-to-wall forest cover map was generated for all of Switzerland, which meets the requirement of the Swiss NFI forest definition. The workflow is highly automated and based on digital surface models from image-based point clouds of airborne digital sensor data. It fully takes into account the four key criteria of minimum tree height, crown coverage, width, and land use. The forest cover map was validated using almost 10,000 terrestrial and stereo-interpreted NFI plots, which verified 97% agreement overall. This validation implies different categories such as five production regions, altitude, tree type, and distance to the forest border. Overall accuracy was lower at forest borders but increased with increasing distance from the forest border. Commission errors remained stable at around 10%, but increased to 17.6% at the upper tree line. Omission errors were low at 1%–10%, but also increased with altitude and mainly occurred at the upper tree line (19.7%). The main reasons for this are the lower image quality and the NFI height definition for forest which apparently excludes shrub forest from the mask. The presented forest mapping approach is superior to existing products due to its national coverage, high level of detail, regular updating, and implementation of the land use criteria.

До питання збільшення довговічності деяких видів кущових рослин

Наведено результати багаторічних досліджень проблеми підвищення віку, лісівничих і декоративних якостей восьми видів кущів: спіреї середньої (Spiraea media Schmidt), с. Вангутта (S. vanhouttei (Brio) Zab.), с. верболистої (S. salicifolia L.), жимолості звичайної (Lonicera xуlosteum L.), ж. татарської (L. tatarica L.), бирючини звичайної (Ligustrum vulgare L.), свидини кров’яної (Cornus sanguinea L.) та с. білої (C. alba L.) у зелених насадженнях міста Біла Церква та у лісових культурах Томилівського лісництва ДП «Білоцерківське лісове господарство». Періодично проводили обрізування їх надземної частини. Встановлено, що обрізування крон з періодичністю 15-17 років сприяє збільшенню довговічності кущів досліджуваних видів на 33-35 років і більше. За відсутності таких заходів повне відмирання кущів відбувається у віці 19-20 років. Періодичне обрізування сприяє також підвищенню лісівничих та декоративних властивостей кущів.

Seed characteristics of Flueggea anatolica, an endangered forest shrub species

Seed characteristics of Flueggea anatolica, an endangered forest shrub species

Chloroplast phylogeography of Dirca palustris L. indicates populations near the glacial boundary at the Last Glacial Maximum in eastern North America

AbstractAimLittle is known about the distribution of temperate forest shrubs in eastern North America during the Last Glacial Maximum (LGM), and how far they subsequently migrated to occupy previously glaciated landscapes. We assessed whether populations of Dirca palustris L. persisted near the glacial margin during the LGM. Such populations might explain how the species colonized northern latitudes, despite scant evidence for contemporary long‐distance seed dispersal.LocationEastern North America, Mexico and California.MethodsWe conducted ecological niche modelling (ENM) and sequenced five non‐coding regions of the chloroplast genome from 390 plants among 104 populations representing the four species of Dirca. We used a Bayesian approach to identify relationships among individuals and to estimate timing of lineage splits. The spatial genetic structure of D. palustris was evaluated qualitatively and by statistical methods, including Monmonier's algorithm and analysis of molecular variance (AMOVA).ResultsEcological niche modelling indicated suitable climate at the LGM in the Gulf Coastal Plain, but also north to the Ozark Plateaus Province (northern Arkansas), Interior Low Plateaus and Appalachian Plateaus Provinces (portions of Tennessee and Kentucky), and the Piedmont and Coastal Plain Provinces of the Carolinas and Virginia. Sequence variation was extensive and indicated deep lineage splits within D. palustris. Numerous haplotypes, many private, were identified at middle latitudes (c. 35–40° N), Monmonier's algorithm identified multiple genetic discontinuities within this region, and northern and southern regions differed by AMOVA.Main conclusionsEcological niche modelling and genetic analyses indicate that populations likely existed within several hundred km of the Laurentide ice sheet at the LGM. Deep Pleistocene diversification, along with weak geographical fidelity of haplotypes, probably resulted from repeated isolation, differentiation, and secondary contact during Quaternary glacial cycles. The absence of many northern haplotypes south of 35° N supports the hypothesis that temperate understorey shrubs accompanied temperate trees of eastern North America in populations near the glacial margin at the LGM.

Complete mitochondrial genome of Garrulax elliotii (Passeriformes, Timaliidae)

Garrulax elliotii belonged to Passeriformes, one of the members of Timaliidae family. It was a kind of unique and resident species habitat in the evergreen broadleaf forest and alpine shrub belt. The complete mitochondrial genome of G. elliotii was constituted by 13 protein-coding genes (PCGs), 22 transfer ribonucleic acid (tRNA) genes, two Ribosomal RNA (12SrRNA and 16SrRNA) genes, and two control regions (D-loop) genes. ND6 and eight tRNA genes (tRNAGln, tRNAAla, tRNAAsn, tRNACys, tRNATyr, tRNASer(UCN), tRNAPro, and tRNAGlu) encoded on light strand, and the other 12 protein-coding genes encoded on heavy strand. Mitochondrial genes had been widely used in studies of phylogenetic relationships, molecular diagnostics, and an important tool for genome architecture, it has a significance mean for us provided the complete mitochondrial genome of G. elliotii to the Timaliidae family construction in the future.

Fourfold Increase in Pumpkin Yield in Response to Low-Dosage Root Zone Application of Urine-Enhanced Biochar to a Fertile Tropical Soil

A widely abundant and invasive forest shrub, Eupatorium adenophorum, was pyrolyzed in a cost-efficient flame curtain kiln to produce biochar. The resulting biochar fulfilled all the requirements for premium quality, according to the European Biochar Certificate. The biochar was either applied alone or mixed with fresh cow urine (1:1 volume) to test its capacity to serve as slow release fertilizer in a pumpkin field trial in Nepal. Treatments included cow-manure compost combined with (i) urine-only; (ii) biochar-only or (iii) urine-loaded biochar. All materials were applied directly to the root zone at a biochar dry matter content of 750 kg·ha−1 before seeding. The urine-biochar treatment led to a pumpkin yield of 82.6 t·ha−1, an increase of more than 300% compared with the treatment where only urine was applied, and an 85% increase compared with the biochar-only treatment. This study showed for the first time that a low-dosage root zone application of urine-enhanced biochar led to substantial yield increases in a fertile silt loam soil. This was tentatively explained by the formation of organic coating of inner pore biochar surfaces by the urine impregnation, which improved the capacity of the biochar to capture and exchange plant nutrients.

The distribution of the Red-crowned Toadlet Pseudophryne australis in the Nepean-Burragorang region of the Sydney Basin

Surveys were conducted for the Red-crowned Toadlet Pseudophryne australis in Burragorang State Conservation Area (SCA), Nattai National Park (NP), Thirlmere Lakes NP and the Upper Nepean SCA west of Sydney, New South Wales using a variety of methods. Scattered populations of Pseudophryne australis were detected by the presence of tadpoles and calling males in a range of vegetation communities. These communities included escarpment grey gum forest, exposed Burragorang sandstone shrub woodland, Nattai sandstone dry shrub forest, sheltered sandstone intermediate blue gum forest and Nepean gorge moist forest. All detections were within non-perennial creeks on Hawkesbury or Mittagong sandstones or enriched soils derived from these sandstones. The number of calling frogs at sites ranged from one to about 400. Nine 250 m transects were surveyed at night for 30 min each and 0–36 adult frogs were detected during these searches. Diurnal searches were conducted for tadpoles and adult frogs by using the ‘shout’ metho...

Spatial and Temporal Changes in Vegetation Phenology at Middle and High Latitudes of the Northern Hemisphere over the Past Three Decades

Vegetation phenology is a key biological indicator for monitoring terrestrial ecosystems and global change, and regions with the most obvious phenological changes in vegetation are primarily located at high latitudes and altitudes. Over the past three decades, investigations of obvious phenological changes in vegetation at middle and high latitudes in the Northern Hemisphere have provided significant contributions to understanding global climate change. In this study, phenological parameters were extracted from the Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI3g) to analyze the spatial and temporal characteristics of vegetation phenological changes above 40°N in the Northern Hemisphere from 1982–2013. The results showed that the start of season (SOS) was significantly advanced (−2.2 ± 0.6 days·decade−1, p < 0.05) and that the end of season (EOS) was slightly delayed (0.78 ± 0.6 days·decade−1, p = 0.21) over the entire study area in the initial 21 years (1982–2002). When the time scale was extended to 2013, the change rate of the SOS and EOS was significantly reduced; in addition, the SOS was delayed (3.2 ± 1.7 days·decade−1, p < 0.05), and the EOS was advanced (4.5 ± 0.9 days·decade−1, p < 0.05) over the entire study area in the last 11 years (2003–2013). The trends of advanced SOS and delayed EOS over the past three decades were slower than those over the initial two decades on a hemispheric scale. The change trends showed obvious variability with different vegetation types and were greater for woody plants than for herbaceous plants. For broad-leaved forest, the SOS was significantly advanced (2 ± 0.5 days·decade−1, p < 0.05) and the EOS was significantly delayed (2.7 ± 0.6 days·decade−1, p < 0.05) from 1982–2013. The trend of delayed EOS was greater than that of advanced SOS for different vegetation types. With respect to the spatial distribution of phenological trends in the Northern Hemisphere, the trends of advanced SOS and delayed EOS were strongest in Europe followed by North America, and the trends were least significant in Asia. Coniferous forest, shrub forest, grassland, and the entire study area have the same change trends for the two time periods (1982–2002 and 2003–2013), and the increased rate of the phenology parameters has decelerated over the most recent decade. The length of season (LOS) of broad-leaved forest and mixed forest over the past 32 years shows a strong increased trend, and simultaneously, the SOS and EOS show an advanced trend and a delayed trend, respectively

Plant–soil interactions promote co‐occurrence of three nonnative woody shrubs

Ecosystems containing multiple nonnative plant species are common, but mechanisms promoting their co-occurrence are understudied. Plant-soil interactions contribute to the dominance of singleton species in nonnative ranges because many nonnatives experience stronger positive feedbacks relative to co-occurring natives. Plant-soil interactions could impede other nonnatives if an individual nonnative benefits from its soil community to a greater extent than its neighboring nonnatives, as is seen with natives. However, plant-soil interactions could promote nonnative co-occurrence if a nonnative accumulates beneficial soil mutualists that also assist other nonnatives. Here, we use greenhouse and field experiments to ask whether plant-soil interactions (1) promote the codominance of two common nonnative shrubs (Ligustrum sinense and Lonicera maackii) and (2) facilitate the invasion of a less-common nonnative shrub (Rhamnus davurica) in deciduous forests of the southeastern United States. In the greenhouse, we found that two of the nonnatives, L. maackii and R. davurica, performed better in soils conditioned by nonnative shrubs compared to uninvaded forest soils, which. suggests that positive feedbacks among co-occurring nonnative shrubs can promote continued invasion of a site. In both greenhouse and field experiments, we found consistent signals that the codominance of the nonnatives L. sinense and L. maackii may be at least partially explained by the increased growth of L. sinense in L. maackii soils. Overall, significant effects of plant-soil interactions on shrub performance indicate that plant-soil interactions can potentially structure the co-occurrence patterns of these nonnatives.

Description of Gaertnera luteocarpa (Gentianales: Rubiaceae), with two subspecies, a new forest shrub species from Liberia, Ivory Coast and Ghana

Gaertnera luteocarpa sp. nov., with two subspecies, is described and illustrated. The new species resembles G. spicata K.Schum. but has yellow, not reddish, fruits. With G. cooperi and G. aurea it shares the ruminate endosperm.

Short-Term Response of Native Flora to the Removal of Non-Native Shrubs in Mixed-Hardwood Forests of Indiana, USA

While negative impacts of invasive species on native communities are well documented, less is known about how these communities respond to the removal of established populations of invasive species. With regard to invasive shrubs, studies examining native community response to removal at scales greater than experimental plots are lacking. We examined short-term effects of removing Lonicera maackii (Amur honeysuckle) and other non-native shrubs on native plant taxa in six mixed-hardwood forests. Each study site contained two 0.64 ha sample areas—an area where all non-native shrubs were removed and a reference area where no treatment was implemented. We sampled vegetation in the spring and summer before and after non-native shrubs were removed. Cover and diversity of native species, and densities of native woody seedlings, increased after shrub removal. However, we also observed significant increases in L. maackii seedling densities and Alliaria petiolata (garlic mustard) cover in removal areas. Changes in reference areas were less pronounced and mostly non-significant. Our results suggest that removing non-native shrubs allows short-term recovery of native communities across a range of invasion intensities. However, successful restoration will likely depend on renewed competition with invasive species that re-colonize treatment areas, the influence of herbivores, and subsequent control efforts.

Emulating natural disturbance in forest management enhances pollination services for dominant Vaccinium shrubs in boreal pine-dominated forests

Lack of natural disturbances and the homogenization of boreal forest because of intensive forest management pose a threat to biodiversity and can endanger the provision of ecosystem services. In this study, we assessed how two methods aimed to promote biodiversity, i.e. prescribed fire and retention forestry (RET), affect ecosystem services supported by bilberry and lingonberry in Scots pine-dominated boreal forests. Shrub cover, flowering, berry yield and percent fruit set of both shrubs were measured and bees were sampled by pan-traps on 24 study sites 13years following a large-scale experiment, where RET (0, 10, 50m3/ha and uncut forests) and fire (yes/no) were manipulated following a replicated factorial design. In general, bilberry performance and reproduction were higher at uncut sites, while lingonberry flowering was positively affected by fire and retention. Bee community composition was mainly determined by percentage of bare ground and number of logs within sites, both nesting resources largely determined by fire and retention. Burnt sites with retention trees serve as pollinator source habitats and contain floral resources, highlighting the importance of natural disturbances and biological legacies in the conservation of pollination services from boreal forests.

Current status of Phytoplasma diseases of forest and landscape trees and shrubs

This paper summarizes the current knowledge of phytoplasma diseases of forest and landscape trees and shrubs, with special reference to molecular and taxonomic aspects of the associated phytoplasmas in the light of the plethora of data generated over the last years. Phytoplasma diseases of such kind of trees and shrubs are of considerable economic and ecological significance throughout the world, either because of the local impact or of their widespread distribution. However, information is still missing on many aspects of some of these diseases, including insect vectors, phytoplasma-vector relationships, phytoplasma-host plant interactions, strain virulence, strain interference, host tolerance, host range, and impact of the infections on the growth and yield of affected plants. In some instances, phytoplasma- infected forest and landscape trees and shrubs can serve as reservoirs of phytoplasmas affecting agricultural crops. Latent phytoplasma infections in some forest and landscape trees and shrubs are common.

Rhamnus cathartica (Rosales: Rhamnaceae) Invasion Reduces Ground-Dwelling Insect Abundance and Diversity in Northeast Iowa Forests.

European buckthorn (Rhamnus cathartica L.) is an invasive woody shrub in deciduous forests of the Upper Midwest. Studies have suggested buckthorn invasion has negative effects on native plants, soil, and ecosystems, but its impacts on insects are largely unstudied. To test the impact of buckthorn invasion on ground-dwelling insects in forests of northeastern Iowa, pitfall traps were used to sample ground-dwelling insects at five sites four different periods from June to August 2013. Each site had three treatments: areas heavily infested with buckthorn, areas where buckthorn has not established, and areas where buckthorn had been removed within the past 2-10 yr. Most insects were identified to family and quantified; while ground beetles (Coleoptera: Carabidae) and ants (Hymenoptera: Formicidae) were identified to species and quantified. In total, 11,576 insects representing eight orders and 46 families were collected. Areas uninvaded by buckthorn had significantly greater insect abundance and taxonomic richness than areas invaded by buckthorn. Of the 948 ground beetles representing 40 species, abundance, species richness, and Shannon diversity indices were significantly lower in areas invaded by buckthorn compared with areas with no buckthorn. The 2,661 ants from 24 species had similar trends, but treatment differences were not significant because of high variability. These results clearly show a negative impact of buckthorn invasion on the abundance and taxonomic richness of ground-dwelling insects.

Density‐dependent Survival in Seedlings Differs among Woody Life‐forms in Tropical Wet Forests of a Caribbean Island

AbstractNegative density dependence contributes to seedling dynamics in forested ecosystems, but the relative importance of this factor for different woody plant life‐forms is not well‐understood. We used 1 yr of seedling survivorship data for woody seedlings in 17 different plots of lower to mid‐montane rain forests on the island of Dominica to examine how seedling height, abiotic factors, and biotic factors such as negative density dependence are related to seedling survival of five different life‐forms (canopy, midstory, and understory trees; shrubs; and lianas). Across 64 species, taller seedlings in seedling plots with higher canopy openness, greater seedling density, lower relative abundance of conspecific seedlings, and lower relative abundance of conspecific adults generally had a greater probability of surviving. Height was the strongest predictor of seedling survival for all life‐forms except lianas. Greater seedling density was positively related to survival for canopy and midstory trees but negatively related to survival for the other life‐forms. For trees, the relative abundance of conspecific seedling and adult neighbors had weak and strong negative effects on survival respectively. Neither shrub nor liana seedling survival was affected by the relative abundance of conspecific neighbors. Thus, negative density dependence is confirmed as an important structuring mechanism for tree seedling communities but does not seem to be important for lianas and shrubs in Dominican rain forests. These results represent the first direct assessment of controls on seedling survival of all woody life‐forms – an important step in understanding the dynamics and structure of the entire woody plant community.