Abundance of two threatened woodpecker species in relation to the proportion of spruce plantations in native pine forests of western Norway

In a comparative study we investigated woodpecker abundance in forest landscapes with different proportion of native pine forest and spruce plantations in western Norway. In 100 circular study plots of 100ha each we recorded 38 white-backed –Dendrocopos leucotos, 22 grey-headed –Picus canus, 13 great spotted –Dendrocopos major, 6 green –Picus viridis, and 2 lesser spotted –Dendrocopos minor woodpeckers in the breeding season. The mean number of recorded woodpecker species peaked at 20–40% spruce plantations. The two most common species in the study, the white-backed and the grey-headed woodpeckers are both Red-listed species in Norway and among the rarest woodpeckers in Europe. The white-backed woodpecker preferred plots with higher than average proportions of standing dead trees and deciduous trees, and low proportions of spruce plantations in the plots. The grey-headed woodpecker preferred plots in the western (coastal) parts of the study area with presence of large aspen Populus tremula trees. Logistic regression models did not reveal any clear threshold values with respect to proportion of spruce plantations in plots, although both woodpecker species were extremely rare in plots with >60% spruce plantations. We recommend spruce plantations to be kept at moderate levels to ensure viable populations of woodpeckers in western Norway.     

Exotic Pine Plantations in Victoria, Australia: A Threat to Epigaeic Beetle (Coleoptera) Assemblages?

Ground-dwelling invertebrates were sampled by pitfall traps over a 14 week period in parent eucalypt forest and three stages of exotic Pinus radiata plantations established after forest clearance in central Victoria. The four treatments each yielded numerous beetle morphospecies, and the assemblages corresponded only partially with the understorey vegetation. More than 200 beetle morphospecies were captured during this short survey, with 30 found in all four treatments; few morphospecies were abundant (only five with >100 individuals in a total of 3382 beetles). Each treatment had unique morphospecies, but all were rich, with the lowest diversity being 91 morphospecies (young pines). These data confirm that beetle diversity can remain substantial in exotic softwood plantations, but considerable care is needed to interpret this apparent diversity in relation to forest management and the effect of replacement of native forests by exotic taxa.     

Species richness and composition of Curculionidae (Coleoptera) in a conifer plantation, secondary forest, and old-growth forest in the central mountainous region of Japan

Weevil (Curculionidae, Coleoptera) species richness and composition were investigated and compared among larch [Larix kaempferi (Lamb.) Carriére] plantations, secondary forests, and old-growth forests in the central mountainous region of Japan. In addition, to assess the effects of forest-management practices, namely thinning and long-rotation logging schedules (long rotation), the weevil assemblages of recently thinned middle-aged and long-rotated larch plantations were compared with those of middle-aged larch plantations. Malaise traps were set in 44 stands of these forest types, and weevils were separated and identified. Several environmental factors other than forest type were also examined. Weevil species richness and diversity indices [Shannon-Wiener diversity index (H) and Simpsons index of diversity (D)] were higher in the secondary forest than in the larch plantation. Because of its wide distribution and higher weevil species richness, the secondary forest contributed to maintaining weevil diversity in this region. Old-growth forest had higher diversity indices (H and D) than did the larch plantation. The secondary forest had the highest number of species in total. Though the number of individuals was the highest in larch plantation, species richness, H and D of the plantation were generally low. Weevil community structure and species composition differed among the three forest types, but the difference in weevil composition between the larch plantation and the other two forest types was the largest. Forest type is probably the most important factor for determining the differences in weevil assemblage, and further, both dominant tree type (coniferous trees versus broad-leaved trees) and the number of mature tree species seem to be important factors for weevil species composition. Among forest management practices, long rotation caused diversity indices (H and D) to increase while thinning appeared to cause only minor changes in the weevil assemblages. Because species richness and species composition of Curculionidae well reflected the differences in forest types and some other environmental factors investigated, this family seems suitable for diversity research in forests. Further research on biodiversity with the use of this family should, therefore, be expected.     

Edge effects and intraguild predation in native and introduced centipedes: evidence from the field and from laboratory microcosms

Human alteration of habitat has increased the proportion of forest edge in areas of previously continuous forest. This edge habitat facilitates invasion of exotic species into remaining fragments. The ability of native species to resist invasion varies and may depend on intrinsic variables such as dispersal and reproductive rates as well as external factors such as rate of habitat change and the density of populations of introduced species in edge habitat. We examined the distributional and competitive relationships of two members of the class Chilopoda, Scolopocryptops sexspinosus, a centipede native to the eastern US, and Lithobius forficatus, an exotic centipede introduced from Europe. We found that L. forficatus was most abundant in edge habitat and S. sexspinosus was most abundant in the interior habitat at our field sites. Although L. forficatus was present in habitat interiors at 11 of 12 sites, there was no correlation between fragment size and numbers of L. forficatus in interior habitat. The native centipede was rarely found occupying fragment edges. We used laboratory microcosms to examine potential competitive interactions and to indirectly assess prey preferences of the two species. In microcosms both species consumed similar prey, but the native centipede, S. sexspinosus, acted as an intraguild predator on the introduced centipede. Native centipedes were competitively superior in both intraspecific and interspecific pairings. Our results suggest that intraguild predation may aid native centipedes in resisting invasion of introduced centipedes from edge habitat.     

The Edible Mushrooms of Madagascar: An Evolving Enigma

The Edible Mushrooms of Madagascar: An Evolving Enigma. This paper on the most significant edible wild mushrooms of Madagascar is organized in the following four categories: (1) mushrooms of introduced eucalypt plantations, (2) mushrooms of introduced pine plantations, (3) mushrooms of native forests and woodlands, and (4) mushrooms found in fields, agricultural waste and other altered, non–forest habitats. Eucalyptus robusta plantations yield by far the bulk of edible mushrooms that are sold, especially species of Russula and Cantharellus. Some Suillus species of northern hemisphere origin have been introduced with pine plantations and are locally important, forming the basis of a small canning industry. In native woodland areas on the central plateau, several ectomycorrhizal mushrooms—very similar to those on the African mainland—are collected and consumed. With the exception of the widely marketed Cantharellus platyphyllus ssp. bojeriensis, these are only of local importance in the villages and smaller markets of the area. Denser forests in the mountains or on the east coast as well as manmade habitats such as fields, pastures, and agricultural wastes are searched for saprobic mushrooms of various types. Some of these saprobic mushrooms show considerable potential for cultivation. The variety of ectomycorrhizal mushrooms found in eucalypt plantations is unprecedented outside of Australia and, for the most part, do not appear to be of Australian origin. Possible reasons for this are briefly discussed. Two economically important species, Russula prolifica sp. nov. and R. edulis sp. nov., are newly described.     

Bird assemblages in pine plantations replacing native ecosystems in NW Patagonia

Forest plantations of exotic conifers represent an important economic activity in NW Patagonia, Argentina. However, there is a remarkable lack of information on the impact of forestry on native biodiversity. We analyzed the effect of Pinus ponderosa plantations on bird communities, considering different stand management practices (dense and sparse tree covers), and different landscape contexts where they are planted (Austrocedrus chilensis forest and steppe). Ultimately we wished to assess in which way plantations may be designed and managed to improve biodiversity conservation. Bird richness and abundance did not change significantly in the steppe, although community composition did, and was partially replaced by a new community, similar to that of ecotonal forests. In contrast, in the A. chilensis forest areas, species richness decreased in dense plantations, but bird community composition remained relatively constant when replacing the native forest with pine plantations. Also, in A. chilensis forest, stand management practices aiming at maintaining low tree densities permit the presence of many bird species from the original habitat. In the steppe area in turn, both dense and sparse plantations are unsuitable for most steppe species, thus it is necessary to manage them at higher scales, maintaining the connectivity of the native matrix to prevent the fragmentation of bird populations. We conclude that pine plantations can provide habitat for a substantial number of native bird species, and this feature varies both with management practices and with the landscape context of areas where afforestation occurs.     

Exotic pine plantations and indigenous Lepidoptera in Australia

Temperate regions of Australia have extensive commercial plantations of Monterey pine, Pinus radiata D. Don. Replacement of indigenous forests by P. radiata is likely to have significant effects on assemblages of native Lepidoptera, and has been considered a major threat to native fauna through displacing native species. However, many species of Lepidoptera, including ennomine geometrid moths in the genus Chlenias Guenèe, have adopted P. radiata as a larval host. Comparisons were made of oviposition preferences and nutritional ecology of Chlenias auctaria Guenée on P. radiata and two native host plants [Acacia mearnsii De Wild. (Mimosaceae) and Eucalyptus obliqua LHérit (Myrtaceae)]. Females showed no significant oviposition preference for any of the three hosts. Growth of sixth instar larvae was significantly less on P. radiata than on the native hosts. Pupal weights were significantly lower, suggesting that the fitness of moths reared on P. radiata will be significantly reduced. The life history strategy of C. auctaria, which includes dispersal of first instar larvae by ballooning, may predispose this species to feed on poor quality hosts, and this may be common to other polyphagous species found feeding on P. radiata in southern hemisphere plantations. The impact of P. radiata may have a long term effect on lepidopteran communities, beyond the simple replacement of indigenous host plants leading to extirpations of feeding specialists.     

The role of rustic coffee plantations in the conservation of wild tree diversity in the Chinantec region of Mexico

Rustic coffee plantations are characterised by the use of numerous wild and cultivated tree species for providing shade to the coffee shrubs. This paper analyses the role of these plantations in wild tree conservation through the examination of their patterns of floristic variation in southern Mexico. The studied plantations included a total of 45 plant species, most of which were wild tree species, including both mature forest and pioneer taxa. An extrapolation of the species accumulation curve among stands indicated that the whole system, composed of more than 100 coffee plantations, may harbour as many as 34 species of wild trees. The floristic structure of rustic coffee plantations was highly variable. This variation is a result of a combination of factors such as human management, original stand cover and the asynchrony in development stage of different plantations. This promotes a large -diversity in the system. Thus, although a single plantation may have a limited potential to preserve wild tree species, it is the whole ensemble of floristically heterogeneous plantations which renders this agroforestry system valuable for plant diversity conservation, particularly in a region where native forest vegetation has almost disappeared.     

Suppression of Regeneration in New Zealand Mountain Beech Forests is Dependent on Species of Introduced Deer

We compared the impacts on forest regeneration of introduced sika (Cervus nippon) and red (Cervus elaphus) deer in New Zealand. Plot data were used to compare mountain beech (Nothofagus solandri var. cliffortioides) regeneration between a region with sika deer, and four regions without sika deer. All regions surveyed had red deer present. In the region where sika deer had been present for more than a decade, there was evidence of poor mountain beech seedling regeneration. In the four regions without sika deer, there was evidence of a strong regenerative response at stands with low occupancy by trees. When compared to larger deer species, sika deer have a digestive morphology allowing greater dietary versatility, which may result in them impeding forest regeneration where red deer do not. In contrast to mountain beech, some small-leaved shrub species may have been competitively advantaged by intensive browsing from sika deer. This is contra to a current view that small-leaved shrub species with interlacing branches were able to tolerate browsing from extinct ratite birds, but not introduced deer. Sika deer have been introduced into countries where other deer species are indigenous, such as Canada, Denmark, Great Britain, Czech Republic, Ireland and the United States of America. Because of their dietary advantage, sika deer may have a greater potential to impede forest regeneration and competitively exclude larger deer species, particularly at low basal area sites where impacts on tree regeneration are likely to be greatest.     

外来树种日本落叶松和日本花柏对鄂西北森林群落的影响

【目的】研究大面积栽植外来树种日本落叶松和日本花柏对鄂西北森林群落物种多样性的影响,为评价外来树种的入侵风险提供依据。【方法】采用样地调查法对比研究外来树种日本落叶松和日本花柏人工林与当地森林群落特征差异。【结果】日本落叶松人工林样地林下植物种类丰富,样地平均物种数与当地天然林样地物种数相比无显著差异;林下灌木层和草本层多样性指数较高,草本层多样性指数与当地天然林相比无显著差异;林下未发现日本落叶松的更新苗。日本花柏人工林样地平均物种数显著少于当地其他人工林样地;乔木层、灌木层和草本层的4个多样性指数值均小于当地其他人工林样地;在3个样地中出现日本花柏更新苗,更新苗数量达479株·hm~(-2)。【结论】引种栽培日本落叶松不会导致当地森林群落的物种多样性降低,不会引起生物入侵风险;但引种栽培日本花柏会明显降低当地森林群落的物种多样性,对当地森林生态系统的稳定构成一定威胁。     

A 10-year study of changes in forest vegetation on Silhouette island, Seychelles

A 10 year study of forest communities on Silhouette island, Seychelles demonstrates stability of forest composition in most areas over this time-scale. Areas with heavy invasion by alien species were found to be regenerating, particularly with the rapid loss of Clidemia hirta. This is attributed to the abundance of well-adapted native plants allowing competitive exclusion to take place, throughout competition for light. It was noted that invasive plant species tend to be unstable on the rocky slopes covered by native high forest. A high rate of tree fall and limited seed dispersal may reduce the impact of the invasive tree Paraserianthes falcataria in the future. Other species such as Cinnamomum verum and Psidium cattleianum may persist as major invaders due to wider seed dispersal.     

Use of mires and food habits of sika deer in the Oze Area,central Japan

Sika deer Cervus nippon entered the Oze Area, a snowy area in central Japan, in the 1990s. The use of mires and the food habits of this species were studied in 1999 and 2000. Deer used the mires immediately after snow melted and did not use the mires in mid summer, although they did use them lightly in autumn. The summer food habits differed from those of the deer population living in Nikko in the lower area: non-Sasa graminoids and other monocotyledonous leaves occupied more (approximately 30%) of the feces in the former population, whereas Sasa nipponica, a dwarf bamboo, was the dominant food (60%) of the latter population. Seasonal changes in fecal composition in the Oze deer were that mire graminoids occupied a considerable portion of their food in spring (11.6%) and summer (17.0%), whereas the amount of dwarf bamboo increased in fall (26.0%). Despite the small size of the mires, Oze deer appear to prefer mires to forests. Nitrogen concentrations of the mire plants did not differ from those of the forest plants; however, foraging efficiency would be greater in the mires and this may explain the preference observed. Despite the small total biomass, leaf biomass of the mire was equivalent to that of the adjacent forest floor. In addition, biomass was concentrated near the ground, or the biomass concentration was greater than that of the forest floor.     

Deer feeding selectivity for invasive plants

Native generalist herbivores might limit plant invasion by consuming invading plants or enhance plant invasion by selectively avoiding them. The role of herbivores in plant invasion has been investigated in relation to plant native/introduced status, however, a knowledge gap exists about whether food selection occurs according to native/introduced status or to species. We tested preference of the native herbivore white-tailed deer (Odocoileus virginianus) for widespread and frequently occurring invasive introduced and native plants in the northeastern United States. Multiple-choice deer preference trials were conducted for the species and relative preference was determined using biomass consumption and feeding behavior. While more native than introduced plant biomass was consumed overall, deer food selection varied strongly by plant species. Results show consistent deer avoidance of several invasive introduced plants (Alliaria petiolata, Berberis thunbergii, and Microstegium vimineum) and a native plant (Dennstaedtia punctilobula). Other invasive introduced plants (Celastrus orbiculatus, Ligustrum vulgare, and Lonicera morrowii) and a native plant (Acer rubrum) were highly preferred. These results provide evidence that herbivore impacts on plant invaders depend on plant species palatability. Consequently, herbivore selectivity likely plays an important role in the invasion process. To the extent that herbivory impacts population demographics, these results suggest that native generalist herbivores promote enemy release of some plant invaders by avoiding them and contribute to biotic resistance of others by consuming them.     

The Potential Impact of An Introduced Shrub on Native Plant Diversity and Forest Regeneration

Over a period of 20 years, Chinese privet, Ligustrum sinense, invaded a mixed hardwood forest in western North Carolina, USA. The invasion penetrated about 30m under the canopy trees, providing 100% cover of the forest floor. Under the privets and in a nearby privet-poor reference area we marked off twenty, one square meter plots with string. All plants in each square meter of both areas were tallied in the spring of 1999 and young trees less than 1m high were again counted in September. We removed privets of the invaded area in November and again tallied all plants in both areas the following spring of 2000. In the spring of 1999, the mean number of herb species per square meter under the privet was 41%, and stem counts 75% less than in the reference area. 42% of herb species found in the reference area were missing under the privet. After removing the privets in the fall of 1999, the number of both native species and stems increased in the privet area the following spring. Plots of density of two native plants against privet density showed both native plants decreasing under increasing privet cover. In the spring of 1999, there were 4 species and 274 stems of tree seedlings in the privet area. In September of that year, we found only one small American holly tree, a highly shade-tolerant species, remaining under the privet. Our data support the thesis that Chinese privet can severely reduce herbaceous species and almost completely suppress tree regeneration in a mixed hardwood forest.     

Is <Emphasis Type="Italic">Pinus radiata</Emphasis> invading the native vegetation in central Chile? Demographic responses in a fragmented forest

Forest fragmentation facilitates the invasion of exotic species. This threat may be especially severe if forest fragments are surrounded by plantations of exotic species like Pinus radiata, an aggressive colonizer and shade-intolerant tree that has invaded successfully several native ecosystems of the southern hemisphere. In this study, we experimentally tested if the conditions of a successful seedling establishment P. radiata are fulfilled at the Coastal Maulino forest, an endemic fragmented forest of central Chile. Results demonstrated that seeds are dispersed into the native forests, however seedling establishment occurs only at the edges. We conclude that this exotic species is not invading native forests up to date. However, we suggest to conduct evaluations of seed rain and seedling establishment in the long term, in order to monitor the fate of this exotic species in fragmented native forest of Central Chile.     

Do exotic pine plantations favour the spread of invasive herbivorous mammals in Patagonia?

Changes in land use patterns and vegetation can trigger ecological change in occupancy and community composition. Among the potential ecological consequences of land use change is altered susceptibility to occupancy by invasive species. We investigated the responses of three introduced mammals (red deer, Cervus elaphus; wild boar, Sus scrofa; and European hare, Lepus europaeus) to replacement of native vegetation by exotic pine plantations in the Patagonian forest‐steppe ecotone using camera‐trap surveys (8633 trap‐days). We used logistic regression models to relate species presence with habitat variables at stand and landscape scales. Red deer and wild boar used pine plantations significantly more frequently than native vegetation. In contrast, occurrence of European hares did not differ between pine plantations and native vegetation, although hares were recorded more frequently in firebreaks than in plantations or native vegetation. Presence of red deer and wild boar was positively associated with cover of pine plantations at the landscape scale, and negatively associated with mid‐storey cover and diversity at the stand scale. European hares preferred sites with low arboreal and mid‐storey cover. Our results suggest that pine plantations promote increased abundances of invasive species whose original distributions are associated with woodlands (red deer and wild boar), and could act as source or pathways for invasive species to new areas.     

Contribution of cocoa plantations to the conservation of native ants (Insecta: Hymenoptera: Formicidae) with a special emphasis on the Atlantic Forest fauna of southern Bahia,Brazil

By maintaining a forest-like structure, shaded cocoa plantations contribute to the conservation of ants that usually live in the soil, leaf litter or canopy of tropical forests. Here we synthesize the available information on the diversity and community structure of ants in shaded cocoa plantations in the Atlantic forest region of Brazil, compare ant assemblages in cocoa agroforests with forests and other forms of agriculture, and discuss how these shaded plantations contribute to the conservation of the ants in the Atlantic Forest region. We also discuss ants of economical importance and of special interest, including Camponotus, Dolichoderus, Gnamptogenys, Pachycondyla, Pseudomyrmex and other litter dwelling genera. We discuss the situation of the tramp ant Wasmannia auropunctata in the Bahian cocoa-producing region where it is considered as native, and that of the two cryptobiotic genera Thaumatomyrmex and Typhlomyrmex, as well as that of proven and possible endangered army ant and Ponerini species. A total of 192 ant species from four strata were found in extensive sampling of a cocoa plantation with a relatively simple shade canopy (comprised primarily of Erythrina). Species richness in the cocoa plantations corresponded roughly to that of low diversity native forests, and species composition of cocoa plantations was most similar to native habitats (forest and mangroves) while ant composition in other agricultural habitats was most similar to that of urban areas. Although occurrences of Wasmannia auropunctata were similar in cocoa plantations and forests, abundance of Thaumatomyrmex and Typhlomyrmex, generally thought to be rare ants, was relatively high in cocoa plantations. These results, from cocoa plantations with relatively simple shade, demonstrate the importance of cocoa for ant conservation in the Atlantic forest region of Brazil. It is likely that cocoa plantations with a greater number of vegetation strata and higher tree species richness (such as traditional cabruca plantations) provide even more important habitat for ants generally and for ant species of conservation concern.     

High tree alpha-diversity in Amazonian Ecuador

In a 1 ha square plot of terra firme forest at 260 m elevation in Amazonian Ecuador, all trees with diameter at breast height (dbh) 5 cm were studied. There were 1561 individuals, 473 species, 187 genera and 54 families. Of these, 693 individuals, 307 species, 138 genera and 46 families had a dbh 10 cm. This is the highest number of tree species ever recorded for a tropical rain forest sample of this size. In both dbh classes, the most species-rich families were: Fabaceae sensu lato (including Mimosaceae and Caesalpiniaceae), Lauraceae and Sapotaceae; the most species-rich genera, were Pouteria, Inga and Protium. The vertical space was partitioned among species: 166 species were found only in the 5–10 dbh cm class and were mostly sub-canopy treelets, and 307 species with dbh 10 cm were mostly large canopy trees.     

Relationship between a high density of sika deer and productivity of the short-grass (<Emphasis Type="Italic">Zoysia japonica</Emphasis>) community: a case study on Kinkazan Island,northern Japan

An extremely high-density (ca. 800 deer km^–2) wild sika deer population uses a short-grass community dominated by Zoysia japonica on Kinkazan Island in northeastern Japan. To explain why the density of wild deer is quite high on the Zoysia community, (1) we quantified the seasonal productivity of the Zoysia community, (2) we compared food availabilities among the plant communities, and (3) we described the habitat selection by the deer in different seasons. Food availability was greater on the Zoysia community than in the forest understory from spring to fall. The productivity of the Zoysia community was high enough to support the actual high density of the deer (814 deer km^–2) in summer. However, the productivity markedly decreased in winter, when the deer density decreased to less than half (358 deer km^–2) of the summer value. In contrast, the deer density of the adjacent forests was highest in winter (154 deer km^–2) and lowest in spring (19 deer km^–2). These results suggest that the deer using the Zoysia community in summer left and were absorbed into the adjacent forest in winter. If such an adjacent community were absent, many deer would not survive, and consequently the deer density on the Zoysia community in summer would not be so high. This intercommunity movement is particularly important for the deer using a plant community like the Zoysia community, which is highly productive but has a small standing biomass.     

A Panax-centric view of invasive species

Plant-centric sampling provides a novel approach to quantifying the potential impact of invasive species on native plant species. The aim of this study was to determine the level of exposure of individuals and populations of Panax quinquefolius to invasive plant species using this approach in thirty natural ginseng populations. A high level of invasion was found with 63–70% of ginseng populations containing at least one invasive species. Approximately one-third of all individuals were found in close proximity to invasive plants. The most prevalent invasive species were Rosa multiflora and Berberis thunbergii. The exposure to invasives of plants in different size classes varied among populations. Invasive species presence increased with greater ginseng population sizes and presence of harvest. The abundance of invasives plants within forest interiors near this valuable medicinal herb suggests that the economic and ecological costs of competitive interactions with native species could be high.