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Different Tree Species (different + tree_species)
Selected AbstractsSpatiotemporal changes of beetle communities across a tree diversity gradientDIVERSITY AND DISTRIBUTIONS, Issue 4 2009Stephanie Sobek Abstract Aim, Plant and arthropod diversity are often related, but data on the role of mature tree diversity on canopy insect communities are fragmentary. We compare species richness of canopy beetles across a tree diversity gradient ranging from mono-dominant beech to mixed stands within a deciduous forest, and analyse community composition changes across space and time. Location, Germany's largest exclusively deciduous forest, the Hainich National Park (Thuringia). Methods, We used flight interception traps to assess the beetle fauna of various tree species, and applied additive partitioning to examine spatiotemporal patterns of diversity. Results, Species richness of beetle communities increased across the tree diversity gradient from 99 to 181 species per forest stand. Intra- and interspecific spatial turnover among trees contributed more than temporal turnover among months to the total ,-beetle diversity of the sampled stands. However, due to parallel increases in the number of habitat generalists and the number of species in each feeding guild (herbivores, predators and fungivores), no proportional changes in community composition could be observed. If only beech trees were analysed across the gradient, patterns were similar but temporal (monthly) species turnover was higher compared to spatial turnover among trees and not related to tree diversity. Main conclusions, The changes in species richness and community composition across the gradient can be explained by habitat heterogeneity, which increased with the mix of tree species. We conclude that understanding temporal and spatial species turnover is the key to understanding biodiversity patterns. Mono-dominant beech stands are insufficient to conserve fully the regional species richness of the remaining semi-natural deciduous forest habitats in Central Europe, and analysing beech alone would have resulted in the misleading conclusion that temporal (monthly) turnover contributes more to beetle diversity than spatial turnover among different tree species or tree individuals. [source] Host specificity of ambrosia and bark beetles (Col., Curculionidae: Scolytinae and Platypodinae) in a New Guinea rainforestECOLOGICAL ENTOMOLOGY, Issue 6 2007JIRI HULCR Abstract 1.,Bark and ambrosia beetles are crucial for woody biomass decomposition in tropical forests worldwide. Despite that, quantitative data on their host specificity are scarce. 2.,Bark and ambrosia beetles (Scolytinae and Platypodinae) were reared from 13 species of tropical trees representing 11 families from all major lineages of dicotyledonous plants. Standardised samples of beetle-infested twigs, branches, trunks, and roots were taken from three individuals of each tree species growing in a lowland tropical rainforest in Papua New Guinea. 3.,A total of 81 742 beetles from 74 species were reared, 67 of them identified. Local species richness of bark and ambrosia beetles was estimated at 80,92 species. 4.,Ambrosia beetles were broad generalists as 95% of species did not show any preference for a particular host species or clade. Similarity of ambrosia beetle communities from different tree species was not correlated with phylogenetic distances between tree species. Similarity of ambrosia beetle communities from individual conspecific trees was not higher than that from heterospecific trees and different parts of the trees hosted similar ambrosia beetle communities, as only a few species preferred particular tree parts. 5.,In contrast, phloeophagous bark beetles showed strict specificity to host plant genus or family. However, this guild was poor in species (12 species) and restricted to only three plant families (Moraceae, Myristicaceae, Sapindaceae). 6.,Local diversity of both bark and ambrosia beetles is not driven by the local diversity of trees in tropical forests, since ambrosia beetles display no host specificity and bark beetles are species poor and restricted to a few plant families. [source] The effect of organic acids on base cation leaching from the forest floor under six North American tree speciesEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2001F. A. Dijkstra Summary Organic acidity and its degree of neutralization in the forest floor can have large consequences for base cation leaching under different tree species. We investigated the effect of organic acids on base cation leaching from the forest floor under six common North American tree species. Forest floor samples were analysed for exchangeable cations and forest floor solutions for cations, anions, simple organic acids and acidic properties. Citric and lactic acid were the most common of the acids under all species. Malonic acid was found mainly under Tsuga canadensis (hemlock) and Fagus grandifolia (beech). The organic acids were positively correlated with dissolved organic carbon and contributed significantly to the organic acidity of the solution (up to 26%). Forest floor solutions under Tsuga canadensis contained the most dissolved C and the most weak acidity among the six tree species. Under Tsuga canadensis we also found significant amounts of strong acidity caused by deposition of sulphuric acid from the atmosphere and by strong organic acids. Base cation exchange was the most important mechanism by which acidity was neutralized. Organic acids in solution from Tsuga canadensis, Fagus grandifolia, Acer rubrum (red maple) and Quercus rubra (red oak) were hardly neutralized while much more organic acidity was neutralized for Acer saccharum (sugar maple) and Fraxinus americana (white ash). We conclude that quantity, nature and degree of neutralization of organic acids differ among the different tree species. While the potential for base cation leaching with organic acids from the forest floor is greatest under Tsuga canadensis, actual leaching with organic anions is greatest under Acer saccharum and Fraxinus americana under which the forest floor contains more exchangeable cations than does the strongly acidified forest floor under Tsuga canadensis. [source] 6000 years of forest dynamics in Suserup Skov, a seminatural Danish woodlandGLOBAL ECOLOGY, Issue 2 2000Gina E. Hannon Abstract 1The history of a forest stand over the last 6000 years has been reconstructed by studying pollen, macrofossils and charcoal from a small, wet hollow in Suserup Skov on the island of Sjælland in eastern Denmark. 2The earliest recorded forest was Tilia -dominated but contained an intimate mixture of many different tree species that included Acer campestre, A. platanoides, Alnus glutinosa, Betula pubescens, Corylus avellana, Frangula alnus, Fraxinus excelsior, Malus sylvestris, Populus tremula, Pinus sylvestris, Quercus robur, Q. petraea, Salix spp., Sorbus aucuparia, Tilia cordata and T. platyphyllos. The preserved fruits of T. platyphyllos confirm its hitherto doubtful status as a native member of the Danish flora. 3The present-day woodland developed after a period of intensive anthropogenic disturbance between , 600 bc and ad 900, during which time open canopy conditions prevailed at Suserup. Fagus sylvatica and Fraxinus excelsior are the dominant trees at present, together with some Quercus robur and Ulmus glabra.4,Charcoal was present in the sediments from most time periods except at the Ulmus decline. In the last 1000 years of the sequence , the period of Fagus dominance , charcoal counts were consistently low. 5Pinus sylvestris was a natural component of this primarily deciduous forest, and the last macrofossil find dates from c. ad 900. Macrofossil Pinus cone scales recorded c. ad 1800 originate from planted individuals. Prior to Fagus dominance, the forest had an open structure partly caused by frequent, low-intensity fires associated with the presence of Pinus sylvestris. 6The replacement of Tilia by Fagus in this forest was catalysed by human activity. If the forest had not been so disturbed, the rich diversity of trees would most probably have persisted up to the present time, with only a moderate-sized Fagus population. [source] Testing mechanisms of coexistence among two species of frugivorous primatesJOURNAL OF ANIMAL ECOLOGY, Issue 4 2006ALAIN HOULE Summary 1We examined mechanisms of coexistence between two congeneric species of frugivorous primates, the blue monkey (Cercopithecus mitis) and the red-tailed monkey (C. ascanius). 2We used giving-up densities (the amount of food which animals leave in a patch) in fruit trees to measure foraging efficiency and to evaluate possible mechanisms of coexistence. Animals with higher giving-up densities are less likely to persist in the company of those with lower giving-up densities because the former are not able to exploit food patches used previously by the latter. We climbed trees to estimate giving-up densities by counting the fruit which primates left behind. 3We tested five possible mechanisms of coexistence. Three mechanisms proposed that each frugivorous species has a lower giving-up density than the other in at least one of the following: (1) different tree species, (2) within-tree foraging zones or (3) seasons. The fourth mechanism predicted that the socially dominant species exploits resources first and that the subordinate species has lower giving-up densities. The final mechanism predicted that one species would find resources more quickly than the other, which would in turn have a lower giving-up density. 4Four of the five mechanisms received no support from our data. Only a trade-off between interspecific dominance and giving-up densities was supported. 5We discuss the generality of our results and possible interactions with other factors. [source] Effects of site and fruit size on the composition of avian frugivore assemblages in a fragmented Afrotropical forestOIKOS, Issue 2 2002M. Githiru Factors influencing the interaction between fruiting trees and their frugivorous seed dispersers in fragmented Afrotropical landscapes are poorly known. With the use of Mantel statistics we analysed assemblages of frugivorous birds on 58 individual trees belonging to 11 species growing in seven Kenyan cloud forest fragments. Overall, frugivores showed little specialization on particular trees. Fruit size explained a substantial amount of the variation in frugivore assemblages among different tree species at the same site. In addition, frugivore assemblages on conspecific trees were significantly more similar when the trees occurred at the same site. This location effect was attributable to the different sites and forest fragments (of different sizes and disturbance levels) varying in the densities and composition of their avian frugivores, vegetation composition and tree fruiting phenologies. It was consolidated further by the low mobility of most of these avian frugivores, particularly their reluctance to cross between forest fragments. Habitat disturbance and fragmentation may therefore have affected fruit selection, with implications for both seed dispersal and regeneration. [source] Release of Juniperus thurifera woodlands from herbivore-mediated arrested succession in SpainAPPLIED VEGETATION SCIENCE, Issue 1 2010Lucía DeSoto Abstract Question: Do abiotic constraints maintain monospecific woodlands of Juniperus thurifera? What is the role of biotic (livestock) versus abiotic (climate) drivers in the recruitment and growth of the different tree species? Location: Cabrejas range, Soria, north-central Spain, 1200 m altitude. Methods: Stand history was reconstructed using dendro-ecology and spatial pattern analysis, combined with historical data of livestock abundances and climatic records. Results: J. thurifera establishment occurred in two distinct pulses, with a tree component establishing in the late 1800s to early 1900s. Quercus ilex and Pinus sylvestris establishment was evident only from the late 1970s onward. Recruitment events were related to reductions in livestock browsing. J. thurifera spatial structure was clumped and Q. ilex showed a short-scale aggregation to J. thurifera trees and saplings. Radial growth trends of J. thurifera saplings, Q. ilex and P. sylvestris were negatively related to livestock density. Summer drought limited the radial growth of all the study species, and P. sylvestris and Q. ilex grew faster than J. thurifera even after considering an age effect. Conclusions: The differences in radial growth patterns and recruitment pulses between species indicate that livestock browsing and not abiotic factors is the main factor controlling plant succession and structural development. In this process, J. thurifera acts as a nurse plant, facilitating the establishment of other tree species. Under the current low pressure from herbivores, formerly pure J. thurifera woodlands will change towards dense stands of mixed species composition. [source] Influence of Forest Type and Tree Species on Canopy-Dwelling Beetles in Budongo Forest, Uganda,BIOTROPICA, Issue 3 2000Thomas Wagner ABSTRACT Beetles were collected on 64 trees of four species (Cynometra alexandri C. H. Wright, Rinorea beniemis (Welwitsch ex Olivier) Kuntze, Teclea nobilis Delile, and Trichilia rubescens Olivier) in Budongo Forest, Uganda, using an insecticidal fogging technique. Selected tree species were abundant, taxonomically not closely related, and different in the shape of leaves, growth form, and size, with heights between 7 and 35 m. Trees were fogged in an old primary forest stand, in an area of secondary forest where selective logging was performed, and in a swamp forest. Eight conspecific trees per forest type were fogged. A total of 29,736 beetles were collected from all trees that could be assigned to 1433 (morpho)-species; 41.6 percent were singletons and 89.6 percent of species were found with less than ten individuals. Abundant beetle taxa included Latridiidae (N= 4093), Chrysomelidae (3952), Staphylinidae (2931), Apioninae (2621), and Curculionidae (2457). Most species-rich groups were Staphylinidae (N= 196 spp.), Curculionidae (189), and Chrysomelidae (148). Abundance increased in the order: primary < secondary < swamp forest. Due to the relatively high dominance of some species in the secondary forest, species richness increased in the order: secondary < primary < swamp forest. Beta diversity measures and factor analysis showed distinct differences among forest types but higher similarity of beetle communities on different tree species within one forest type. The taxonomic distribution of beetles in the secondary forest was more heterogeneous than in the primary forest. Analyses of the data revealed low host specificity even for phytophagous beetles, underlining the importance of habitat structure and chance effects on the spatial distribution of beetles in the canopy of Budongo Forest. [source] | |||||||||||||