Short‐term efficacy and nontarget effects of aerial glyphosate applications for controlling Lonicera maackii (Amur honeysuckle) in oak‐hickory forests of Eastern Missouri,U.S.A.

Lonicera maackii (Amur honeysuckle) is a non‐native species that has invaded forest stands throughout the eastern United States. This research examined using aerially applied glyphosate in autumn 2013 to control L. maackii in oak‐hickory forest stands in Missouri, U.S.A. We targeted the spraying time period when L. maackii was still green and most native plants were dormant. Across treatment units, the mean difference in L. maackii stem density significantly declined (p = 0.004) by 5.4 stems per plot from spring 2013 to summer 2014 when compared to control units which increased by 1.8 stems per plot. Treated units with a high initial infestation level of L. maackii (>50% cover) had a significant (p = 0.004) decline in the mean difference in L. maackii cover of ?50.0% per plot between spring 2013 and summer 2014 compared to an average increase of 9.2% in the controls. Similar results were found for treated units with a low initial infestation level of L. maackii (10–50% cover). Mortality of native overstory and understory trees post‐treatment was negligible. In the ground layer of forest stands with a low initial L. maackii infestation level, native non‐spray‐sensitive forb cover per plot significantly increased (p = 0.023) relative to controls between summer 2013 and summer 2014 while native spray‐sensitive species cover significantly decreased (p = 0.021) during the same period. These results suggest that an aerial application of glyphosate can provide an L. maackii control option, but with trade‐offs in compositional shifts in the native ground‐layer vegetation.     

Response of Understory Species to Gap Formation and Soil Disturbance m Lonicera maackii Thickets

We studied the utility of gap formation and soil disturbance as methods to enhance establishment of plant species in the understory of a northern Kentucky forest where Lonicera maackii (Amur honeysuckle) produced dense thickets. In May 1994, gaps (5 m diameter) were cut in the shrub thicket. In adjacent areas, the shrub canopy remained intact. Subplots were established where soil was either turned with a spade to a depth of 15 cm or not disturbed. We monitored plant establishment for three growing seasons (1994, 1995, and 1996). Shrub removal increased light availability to about 10% of full sun. Gap formation had a significant (p < 0.05) and positive influence on total plant density (exclusive of L. maackii), and soil disturbance did not (p > 0.05). After three growing seasons, the most important species were L. maackii, Alliaria petiolata, Parthenocissus quinquefolia, Vitis vulpina, and Acer negundo. Of these species, only V. vulpina showed significantly (p < 0.05) higher densities in gaps. Other less important species such as Phytolacca americana, Campsis radicans, and Eupatorium rugosum occurred almost exclusively in gaps. Of the 44 taxa observed in this study, most were generalist species that also occur in early successional habitats. Long-term dominance of the understory by L. maackii has likely modified system attributes with corresponding effects on community development. Shrub removal provides a window of establishment for various plant species, but successful restoration may require further management species availability and to control new invaders.     

Individual and interactive effects of Amur honeysuckle (Lonicera maackii) and white-tailed deer (Odocoileus virginianus) on herbs in a deciduous forest in the eastern United States

Invasive Amur honeysuckle (Lonicera maackii) has reduced diversity, growth, and reproduction of native herbs in the Midwest USA. These effects may be compounded by browsing from overabundant white-tailed deer (Odocoileus virginianus). We used experimental treatments of honeysuckle (present, absent, removed) and deer (present, excluded) to measure their independent and interactive impacts on diversity, richness, and abundance of herbs in a deciduous forest in southwestern Ohio, USA. Species diversity and richness of herbs were not affected by honeysuckle or deer. Honeysuckle reduced abundance of annuals, graminoids, spring perennials, and summer perennials; deer decreased abundance of annuals and spring perennials, but increased abundance of graminoids. A deer × honeysuckle interaction showed that when honeysuckle was absent or removed, browsing by deer kept abundance of annuals and spring perennials low. Effects of honeysuckle and deer also were assessed for the three most abundant herbs: honeysuckle reduced abundance of Carex rosea and Sanicula odorata, and deer reduced abundance of Viola soraria. Herb abundance varied seasonally and annually. Honeysuckle and deer reduced number of leaves/stem of Maianthemum racemosum and a deer × honeysuckle interaction indicated that the negative effect of honeysuckle was released only when deer were excluded. Herb abundance and M. racemosum rebounded to or near to control levels after removal of honeysuckle. Our findings revealed that impacts of invasive honeysuckle or overabundant deer were not the same across all levels of biological organization (i.e., individual species, growth forms, community measures of species diversity/richness). Measuring impacts of these species at multiple levels of biological organization, considering deer × honeysuckle interactions, and collecting data for several years to account for seasonal and annual fluctuations will help guide management plans. The rapid response by herbs to removal of honeysuckle demonstrated the resilience of this community and is a hopeful sign for restoration of native understory herbs.     

Defoliation by a native herbivore,Omphalocera munroei,leads to patch size reduction of a native plant species,Asimina triloba,following small-scale removal of the invasive shrub,Amur honeysuckle,Lonicera maackii

Plant Ecology - Efforts to reduce the impact of invasive plant species, such as the Amur honeysuckle, Lonicera maackii, often involve the rapid removal of the invasive without any post-removal...     

Large-Scale Removal of Invasive Honeysuckle Decreases Mosquito and Avian Host Abundance

Invasive species rank second only to habitat destruction as a threat to native biodiversity. One consequence of biological invasions is altered risk of exposure to infectious diseases in human and animal populations. The distribution and prevalence of mosquito-borne diseases depend on the complex interactions between the vector, the pathogen, and the human or wildlife reservoir host. These interactions are highly susceptible to disturbance by invasive species, including terrestrial plants. We conducted a 2-year field experiment using a Before–After/Control–Impact design to examine how removal of invasive Amur honeysuckle (Lonicera maackii) in a forest fragment embedded within a residential neighborhood affects the abundance of mosquitoes, including two of the most important vectors of West Nile virus, Culex pipiens and Cx. restuans. We also assessed any potential changes in avian communities and local microclimate associated with Amur honeysuckle removal. We found that (1) removal of Amur honeysuckle reduces the abundance of both vector and non-vector mosquito species that commonly feed on human hosts, (2) the abundance and composition of avian hosts is altered by honeysuckle removal, and (3) areas invaded with honeysuckle support local microclimates that are favorable to mosquito survival. Collectively, our investigations demonstrate the role of a highly invasive understory shrub in determining the abundance and distribution of mosquitoes and suggest potential mechanisms underlying this pattern. Our results also give rise to additional questions regarding the general impact of invasive plants on vector-borne diseases and the spatial scale at which removal of invasive plants may be utilized to effect disease control.     

Restoration of a Forest Understory After the Removal of an Invasive Shrub, Amur Honeysuckle (Lonicera maackii)

The recruitment of native seedlings is often reduced in areas where the invasive Amur honeysuckle (Lonicera maackii) is abundant. To address this recruitment problem, we evaluated the effectiveness of L. maackii eradication methods and restoration efforts using seedlings of six native tree species planted within eradication and unmanipulated (control) plots. Two eradication methods using glyphosate herbicide were evaluated: cut and paint and stem injection with an EZ‐Ject lance. Lonicera maackii density and biomass as well as microenvironmental characteristics were measured to study their effects on seedling growth and survivorship. Mean biomass of Amur honeysuckle was 361 ± 69 kg/ha, and density was 21,380 ± 3,171 plants/ha. Both eradication treatments were effective in killing L. maackii (≥ 94%). The injection treatment was most effective on large L. maackii individuals (>1.5 cm diameter), was 43% faster to apply than cutting and painting and less fatiguing for the operator, decreased operator exposure to herbicide, and minimized impact to nontarget vegetation. Deer browse tree protectors were used on half of the seedlings, but did not affect survivorship or growth. After 3 years, survival of native seedlings was significantly less where L. maackii was left intact (32 ± 3%) compared with the eradication plots (p < 0.002). Seedling survival was significantly different between cut (51 ± 3%) and injected (45 ± 3%) plots. Species had different final percent survival and rates of mortality. Species survival differed greatly by species (in descending order): Fraxinus pennsylvanica > Quercus muehlenbergii ≥ Prunus serotina≥ Juglans nigra > Cercis canadensis > Cornus florida. Survivorship and growth of native seedlings was affected by a severe first‐year drought and by site location. One site exhibited greater spring soil moisture, pH, percent open canopy, and had greater survivorship relative to the other site (55 ± 2 vs. 30 ± 2%). Overall, both L. maackii eradication methods were successful, but restorationists should be aware of the potential for differential survivorship of native seedlings depending on species identity and microenvironmental conditions.     

Springtime in the city: exotic shrubs promote earlier greenup in urban forests

Despite the widespread recognition that urban areas are frequently dominated by exotic and invasive plants, the consequences of these changes in community structure have not been explicitly considered as an explanation for the pattern of advanced leaf phenology, or early greenup, reported in many urban areas. As such, we evaluated two hypotheses that could account for advanced greenup in forests along an urban to rural gradient: advanced phenology within individual species or differences in woody plant community. We monitored the spring leafing phenology of Aesculus glabra (Ohio buckeye), Lonicera maackii (Amur honeysuckle), and Acer negundo (box elder) in 11 forests spanning an urban to rural gradient in central Ohio, USA. From February to April 2006, we monitored these species, recorded woody plant composition, and documented daily minimum and maximum temperatures at each site. We found a weak but general trend of advanced phenology within species in more urban landscapes. Monthly average minimum temperatures were higher with increasing urbanization while monthly average maximum temperatures were similar across the urban to rural gradient. We also found evidence for shifts in woody plant communities along the urbanization gradient, mainly driven by the abundance of L. maackii, an invasive exotic species, in the more urban forests. Because L. maackii leafs out weeks earlier than native woody species and is very abundant in urban forests, we suggest that the invasion of forests by this species can generate earlier greenup of urban forests.     

Soil and vegetation recovery following alien tree clearing in the Eastern Cape Province of South Africa

The impact of alien tree clearing on soil and vegetation recovery remains largely understudied. This study focused on changes in soil and vegetation properties following Acacia removal. The aim was to quantify the long‐term consequences of alien clearing. Paired cleared (old – 15 years; medium – 11 years; recent – 6 years) and uncleared sites were selected along the Palmiet catchment in Eastern Cape Province, South Africa. Various soil physico‐chemical properties (soil moisture, pH, P, N, C, K, Na, Ca, Mg and soil repellency) and vegetation diversity measures were studied on 10 m × 10 m plots. Results indicate that measured soil nutrients are significantly (P < 0.05) lower in cleared than in uncleared sites. However, comparisons among cleared sites alone indicate that soil properties are recovering with older cleared sites having higher (P < 0.05) nutrients than recent cleared sites. Soils in uncleared sites are more repellent than soil in cleared sites. Vegetation recovery in cleared sites was taking place with older cleared sites having higher native species diversity than recently cleared site. We conclude that the removal of alien plants could have caused a reduction in soil nutrients. However, as native vegetation recovers on cleared sites, soil nutrients are gradually improving.     

Relationship Between Fecal Pellet Counts and Snowshoe Hare Density in Western Wyoming

ABSTRACT Snowshoe hares (Lepus americanus) are an important prey species for Canada lynx (Lynx canadensis) and are considered critical for lynx population persistence. Determination of snowshoe hare distribution and abundance is needed by land management agencies for lynx conservation. An accepted approach for estimating snowshoe hare abundance is the use of fecal-pellet plot counts. Locally derived regression equations are preferred for accurate calibration of pellet counts to snowshoe hare density due to local differences in pellet deposition and decomposition. We used linear regression to examine correlations between snowshoe hare density, as determined by mark–recapture estimates, and pellet plot counts on both uncleared plots and annually cleared plots on the Bridger-Teton National Forest, western Wyoming, USA. We found significant correlations between snowshoe hare density estimates and fecal pellet counts for both uncleared and annually cleared pellet counts; however, the relationship was stronger (higher r) when using pellet counts from annually cleared plots. In addition, we found that adjusting the buffer size by omitting hard habitat edges (not used by hares) around trapping grids improved correlations between snowshoe hare density and fecal pellet counts for both uncleared plots and annually cleared plots. Though precision is sacrificed when using uncleared plots, they may be useful as a coarse index of habitat use by snowshoe hares. Our derived regression equations may be useful to identify important foraging habitat for Canada lynx in western Wyoming. Land managers responsible for conserving snowshoe hare habitat in western Wyoming may use these equations to monitor changes in hare populations among habitats and during prescribed management actions.     

Seasonal and diurnal patterns of photosynthetic gas exchange for Lonicera sempervirens and L. Japonica (Caprifoliaceae)

Photosynthesis, stomatal conductance, and water use efficiency were compared between Lonicera japonica (Japanese honeysuckle), an invasive species in the southeastern United States, and its native congener, Lonicera sempervirens (coral honeysuckle), to determine the role of seasonal patterns of water loss and carbon gain in the invasive ability of the exotic. Diurnal measurements were taken monthly for 1 year under a closed forest canopy and in an open field. There were few significant differences in photosynthetic rates between the two species in either environment. However, at both sites, Lonicera japonica retained its old leaves over winter while old leaves of L. sempervirens senesced. Also, new leaves of L. japonica had significantly higher photosynthetic rates than the emerging leaves of L. sempervirens (6.2 vs. 4.4 μmol m ²sec^-1 under the canopy; 4.4 vs. 3.0 μmol m^-2 sec^-1 in the open). Although differences in conductance and water use efficiency between species were seldom significant, L. japonica tended to have higher maximum values than L. sempervirens. Retention of old leaves by L. japonica during new leaf formation (January–March) as well as higher photosynthetic rates in new leaves contribute to greater annual carbon gain and help explain the invasive ability of Japanese honeysuckle.     

Lost in the weeds: Ligustrum sinense reduces native plant growth and survival

Plant invasions are often implicated in declines of native plant species. However, common experimental designs have received criticism questioning the assumption that invasive plants are the primary cause for ecosystem deterioration. We used a combination of field observations and a transplant experiment to investigate the influence of an exotic invasive shrub, Ligustrum sinense (Chinese Privet) on native plant species in Piedmont floodplain forests of South Carolina, USA. We conducted vegetation surveys of 12 floodplain forests documenting abundance and cover of all herbaceous and woody plant species. Additionally, we established an experimental garden to compare survival and growth of L. sinense and four common native species transplanted into a mature L. sinense stand and an adjacent uninvaded area over two growing seasons. The vegetation survey demonstrated a strong negative relationship between L. sinense presence and herbaceous vegetation. As L. sinense cover increased, herbaceous cover and height, plant abundance, and native species richness decreased. In our transplant experiment we found drastic effects of L. sinense on native plant seedling survival and growth. Survival for all native species was lower under the L. sinense canopy and native seedling growth was substantially reduced. Results from both the vegetation survey and transplant experiment show that invasion of L. sinense suppresses herbaceous understory and prevents regeneration of native species by reducing seedling survival and growth. With an approach that combines multiple field sites and local site-specific investigations our research provides strong evidence that L. sinense is an agent of change in floodplain forests.     

The influence of the invasive shrub, Lonicera maackii, on leaf decomposition and microbial community dynamics

Amur honeysuckle (Lonicera maackii) is an exotic invasive shrub that is rapidly expanding into forests of eastern North America. This species forms a dense forest understory, alters tree regeneration, negatively affects herb-layer biodiversity, and alters ecosystem function. In a second-growth forest in central Kentucky, we examined the timing and production of leaf litter and compared litter chemistry, decay rates, and microbial community colonization of Amur honeysuckle to that of two native trees, white ash (Fraxinus americana) and hickory (Carya spp.). The distribution of Amur honeysuckle was clumped, allowing us to compare differences in decomposition under and away from Amur honeysuckle shrubs. Amur honeysuckle leaf litter had significantly higher nitrogen, lower C:N, and lower lignin than the other species, and decomposition rates were greater than 5×?faster. Despite the much higher rate of Amur honeysuckle decomposition compared with the native species (p?<?0.0001), decomposition of all species was significantly slower (p?=?0.0489) in sites located under Amur honeysuckle shrubs. Nitrogen concentration increased through time in decomposing Amur honeysuckle litter; however, total mass of N rapidly declined. We found the initial microbial community on leaf litter of Amur honeysuckle was distinct from two native species and although all microbial communities changed through time, the microbial community of Amur honeysuckle remained distinct from native communities. In summary, a distinct microbial community that may originate on Amur honeysuckle leaves prior to senescence could explain the rapid decay rates.     

Interactions between two co-dominant, invasive plants in the understory of a temperate deciduous forest

Negative interactions between non-indigenous and native species has been an important research topic of invasion biology. However, interactions between two or more invasive species may be as important in understanding biological invasions, but they have rarely been studied. In this paper, we describe three field experiments that investigated interactions between two non-indigenous plant species invasive in the eastern United States, Lonicera japonica (a perennial vine) and Microstegium vimineum (an annual grass). A press removal experiment conducted within a deciduous forest understory community indicated that M. vimineum was a superior competitor to L. japonica. We tested the hypothesis that the competitive success of M. vimineum was because it overgrew, and reduced light available to, L. japonica, by conducting a separate light gradient experiment within the same community. Shade cloth that simulated the M. vimineum canopy reduced the performance of L. japonica. In a third complementary experiment, we added experimental support hosts to test the hypothesis that the competitive ability of L. japonica is limited by support hosts, onto which L. japonica climbs to access light. We found that the abundance of climbing branches increased with the number of support hosts. Results of this experiment indicate that these two invasive species compete asymmetrically for resources, particularly light.     

Impacts of clearing,fragmentation and disturbance on the bird fauna of Eucalypt savanna woodlands in central Queensland,Australia

Abstract This study reports on the responses of bird assemblages to woodland clearance, fragmentation and habitat disturbance in central Queensland Australia, a region exposed to very high rates of vegetation clearance over the last two to three decades. Many previous studies of clearing impacts have considered situations where there is a very sharp management contrast between uncleared lands and cleared areas: in this situation, the contrast is more muted, because both cleared lands and uncleared savanna woodlands are exposed to cattle grazing, invasion by the exotic grass Cenchrus ciliaris and similar fire management. Bird species richness (at the scale of a 1‐ha quadrat) was least in cleared areas (8.1 species), then regrowth areas (14.6 species), then uncleared woodlands (19.9 species). Richness at this scale was unrelated to woodland fragment size, connectivity or habitat condition; but declined significantly with increasing abundance of miners (interspecifically aggressive colonial honeyeaters). At whole of patch scale, richness increased with fragment size and decreased with abundance of miners. This study demonstrates complex responses of individual bird species to a regional management cocktail of disturbance elements. Of 71 individual bird species modelled for woodland fragment sites, the quadrat‐level abundance of 40 species was significantly related to at least one variable representing environmental position (across a rainfall gradient), fragment condition, fragment size and/or connectivity. This study suggests that priorities for conservation management include: cessation of broad‐scale clearing; increased protection for regrowth (particularly where this may bolster connectivity and/or size of woodland fragments); control of miners; maintenance of fallen woody debris in woodlands; increase in fire frequency; and reduction in the incidence of grazing and exotic pasture grass.     

Effects of late growing-season and late dormant-season prescribed fire on herbaceous vegetation in restored pine-grassland communities

Abstract. We compared the effects of late dormant-season and late growing-season prescribed fires on herbaceous species in restored shortleaf pine- (Pinus echinata) grassland communities in the Ouachita Highlands of western Arkansas. Herbaceous species richness, diversity, and total forb and legume abundance increased following fire. Late growing-season burns reduced distribution and abundance of panicums (primarily Panicum boscii, P. dichotomum, and P. linearifolium) while late dormant-season burns increased Panicum distribution and abundance. Density of legumes (such as Stylosanthes biflora) increased following frequent or annual dormant-season fires. However, season of fire influenced the distribution and abundance of fewer than 10 % of the species. Fire plays an essential role in pine-grassland communities by creating and maintaining open canopy conditions that perpetuate understory herbaceous plant communities.     

Impact of the invasive shrub Amur honeysuckle (Lonicera maackii) on shrub-layer insects in a deciduous forest in the eastern United States

Invasive Amur honeysuckle (Lonicera maackii) creates a dense shrub layer in deciduous forests in eastern North America that negatively impacts native herbs and tree seedlings. We predicted that higher vegetative cover caused by this shrub would increase abundance and diversity of insects and alter composition of insect assemblages. We used paired plots, one with and one without honeysuckle, in ten forest locations in southwestern Ohio, USA, to sample insects and measure diversity and vertical cover of vegetation in the shrub layer. Vertical cover of this vegetation was higher on honeysuckle-present plots, but diversity of shrub-layer vegetation did not differ between honeysuckle-present and honeysuckle-absent plots. Species diversity of Hexapoda, Coleoptera, and Psocoptera, richness of Hexapoda, Coleoptera, Diptera, Hymenoptera, and Psocoptera, and abundance of Hexapoda, Diptera, Hymenoptera, and Psocoptera were higher on honeysuckle-present than on honeysuckle-absent plots. Evenness did not differ between honeysuckle treatments. Nonmetric multidimensional scaling distinguished taxonomic composition in honeysuckle-present plots from that in honeysuckle-absent plots. Presence of vertical cover explained higher richness of Hexapoda and Coleoptera, and higher abundance of Hexapoda, Diptera, Hymenoptera, and Psocoptera. Attributes of honeysuckle, independent of its contribution to vertical cover, explained increases in richness of Hexapoda, Coleoptera, and Hymenoptera and abundance of Hexapoda, Hymenopera, and Psocoptera. These attributes of honeysuckle could include a more complex vegetative structure, a greater availability of resources such as food, detritus, or shelter, and/or a more favorable cooler and moister microenvironment. To more fully understand the mechanisms causing increased richness and abundance of insects in honeysuckle-present areas, detailed studies on these attributes of honeysuckle would be necessary.     

Phylogenetic analysis of the polymorphic 4× species complex Lonicera caerulea (Caprifoliaceae) using RAPD markers and noncoding chloroplast DNA sequences

The blue-berried honeysuckle (Lonicera caerulea L.) is one of the most representative species of the genus Lonicera L. in horticulture. This article presents the results of research on the taxonomy of blue-fruited honeysuckles, which is quite complicated due to the phenotypic plasticity, ability to hybridize and distribution across different ecological zones. We used the random amplified polymorphic DNA (RAPD) markers and sequencing of seven chloroplast DNA (cpDNA) regions (trnH-psbA, rpS12-rpL20, trnL-trnF, trnS-trnG, trnG, rpS16 and trnS-psbZ) to assess the phylogenetic relationships among the taxa within the polymorphic 4 × species complex L. caerulea and to determine the position of Lonicera boczkarnikowae Plekh. and Lonicera venulosa Maxim. within this complex. Lonicera chrysantha Turcz. ex Ledeb., L. orientalis Lam. and L. xylosteum L. were used as the outgroup species. The RAPD and cpDNA analyses both indicated that all of the studied taxa of the blue-fruited honeysuckle form a single cluster consisting of two subclusters. A second cluster includes the outgroup species. According to the cpDNA analysis, L. boczkarnikowae and L. venulosa belong to the subcluster that includes the taxa of the polymorphic tetraploid complex L. caerulea. A separate subcluster within the cluster of blue-fruited honeysuckles contains L. altaica and L. edulis.     

Extracts of the invasive shrub Lonicera maackii increase mortality and alter behavior of amphibian larvae

Water-soluble phytochemicals produced by invasive plants may represent novel elements of invaded ecosystems that can precipitate a variety of direct and indirect effects on native organisms. Phenolic compounds in particular are a common plant defense, and these compounds may have disproportionate impacts on amphibians compared to other taxa. We coupled an exploration of invasive plant extract effects on larvae of four amphibian species (the salamander Ambystoma maculatum, the toad Anaxyrus americanus, and the frogs Hyla sp. and Lithobates blairi) with behavioral observations designed to determine whether behavior can ameliorate the negative effects of exposure to invasive plant extracts. Larvae were reared in extracts of the widespread invasive Amur honeysuckle (Lonicera maackii), mixed native leaf litter, and a water control. Anaxyrus americanus tadpoles reared in L. maackii extracts were more likely to die than tadpoles reared in native extracts, but differences in mortality following rearing in native and exotic extracts were not significant for the other three species. Anaxyrus americanus and L. blairi tadpoles made more trips to the surface in L. maackii extracts than in native extracts, consistent with the hypothesis that exotic extracts may interfere with respiratory physiology and suggesting that L. blairi can behaviorally ameliorate the negative effects of L. maackii extracts. Our study highlights both a direct and indirect pathway by which invasive plant extracts may alter the ecological dynamics of native fauna.     

Butterfly diversity and silvicultural practice in lowland rainforests of Cameroon

Butterfly diversity and abundance were sampled across eight 1-ha silvicultural treatment plots in southern Cameroon. The plotsincluded a cleared and unplanted farm fallow, cleared and replanted forestplots, and uncleared forest plots. The replanted plots were line-planted withTerminalia ivorensis, but differed in the degree and methodof clearance. A total of 205 species of butterflies were collected over twodifferent seasons. Several sampling methods were used, including hand collecting andbaited canopy traps. Sites with the greatest degree of disturbance andlowest level of tree cover had the lowest number of individuals and species ofbutterflies. The farm fallow had substantially fewer individuals and species ofbutterflies than the other plots. The replanted plots were intermediate betweenthe farm fallow and uncleared forest in terms of abundance, richness andcomposition. With all three forms of multivariate analysis (Morisita similarityindex clustering, detrended correspondence analysis and two-way indicatorspecies analysis) largest differences were found between the farm fallow anduncleared forest plots. The butterfly fauna of the uncleared forest more closelyapproximated that of the manually cleared plot than that of the mechanicallycleared plot. We found that although, in general, young replanted forest plotsare a poor substitute for native forest, they do provide habitat for some forestspecies and that this may increase over time as the plots mature.     

晋西北丘陵风沙区柠条林下草本植物群落组成和种群生态位变化特征

晋西北丘陵风沙区生态环境脆弱,是我国风沙活动危害最为严重的地区之一。为探究晋西北丘陵风沙区人工柠条林林下草本植物群落组成和种群生态位变化规律,以不同种植年限(撂荒地CK、6、12、18、40、50 a)人工柠条林林下天然草本植物群落作为研究对象,对其群落组成、重要值及种群生态位变化特征进行分析。研究结果表明：(1)不同年限柠条林下天然草本植物组成共记录到22科41属52种,其中,种植前期(0—6 a)林下草本植物以一年生草本植物为优势类群,伴有少数多年生草本植物(3种);种植中期(12—18 a)林下草本植物主要由多年生草本植物(12种)为主,伴生有一年生草本植物(6种)及天然灌木(2种)组成;在种植后期(40—50 a),林下草本植物依然以多年生草本植物(12种)为主。(2)在不同年限柠条林下,草本植物生态位宽度和生态位重叠发生明显变化,种植前期(0—12 a)的优势类群为一年生先锋物种(米蒿和野燕麦),其生态位宽度最宽(9.46、9.34),且与其他物种的生态位重叠程度最大(0.3、0.29);而种植中后期(18—50 a)优势类群变为多年生草本植物,优势种披碱草与其他物种的生态位...