bluuebunny/crossref_metadata_2025_split huggingface dataset:
Space use in the root vole: basic patterns and variability
Authors: Gliwicz Joanna 
Published: July 2006

Home range characteristics and spatial organization of the root vole Microtus oeconomus were assessed by radio‐tracking The aim of this paper is to test the assumption that each microtine species employs a certain modal spatial system around which there is considerable flexibility In the studied population the basic modes of spatial organization were female territoriality and male use of overlapping home ranges Female territories were significantly smaller and less diversified in size than male ranges The size of male home ranges was positively correlated with body mass Each female territory was overlapped by several male ranges, larger male ranges usually overlapped more female territories The above spatial organization suggests that the prevailing mating system in the root vole is promiscuity, and larger males have an access to more receptive females than have small‐sized malesDepartures from these basic modes were found among young mature females from summer cohort, forming clusters even at low density, and occasionally among females in locally crowded habitat patches, where they held overlapping home ranges A single male usually monopolized such a cluster, excluding other males from the area used by the females
Long‐term variation in, and effects of fertiliser addition on, flower, fruit and seed production in the tree Sorbus aucuparia (Rosaceae)
Authors: Sperens Ulf 
Published: July 2006

In this paper, I present long‐term data on reproduction for the tree Sorbus aucuparia Variation in fruit‐set (6 yr) m 22 trees in one population is described and related to flower predation, climate and floral display size Fruit production is described for 7 yr m eight trees in each of four populations and related to climate An additional study, application of a mineral fertiliser, was conducted to test if nutrient availability affected flower, fruit and seed productionThe descriptive study showed that mean fruit‐set differed significantly between individuals and years The ranges of yearly mean proportion of initiated fruit/flower, mature fruit/initiated fruit and mature fruit/flower were large (12‐41%, 2‐72% and 0 3‐23%, respectively) Predation of flowers was low, 1% on average (range 0 3‐2%) Between‐year variations in fruit‐set were positively correlated (though not significant) with precipitation during the phase of initiation and maturation of fruits, respectivelyFruit‐set was independent of floral display size when expressed as number of inflorescences per tree However, when floral display size was expressed as number of flowers per inflorescence, there was a tendency for large inflorescences to have a smaller proportion of initiated fruit/flower and mature fruit/flower than small inflorescencesThe number of fruits produced by the four populations studied varied significantly among years, populations and individuals Individual fruit production varied considerably between the worst and the best fruiting year (range = 101‐103'x) Annual average fruit production m the populations was found to be in general positively correlated with precipitation the preceding year and negatively correlated with temperature, irradiance and fruit production the preceding year However, none of these correlations reached statistical significanceIn the fertilisation experiment, experimental trees produced significantly more flowers, fruits and seeds per tree, compared with control trees This increase was due to an increased number of inflorescences per tree and number of flowers per inflorescence In none of the years, irrespective of flowering, did experimental trees produce proportionally more fruits (i e larger fruit‐flower ratio) and more seeds per fruit than control trees Furthermore, experimental and control trees showed similar inter‐annual variation m flower and fruit production
Mass balance and nitrogen accumulation in hummocks on a South Swedish bog during the late Holocene
Authors: Malmer Nils , Svensson Göran , Wallén Bo 
Published: July 2006

Two peat cores from the Store Mosse mire in the central part of South Sweden have been analyzed for dry bulk density, carbon, and nitrogen They cover the development of the peat mound from the time of the conversion of the initial fen to an ombrotrophic bog at 5450 BP through three different bog stages, the Fuscum. the Rubellum‐Fuscum and the Magellanicum bog stages, each one characterized by a specific macrofossil assemblageAll N supplied to the bog surface is assumed to be contained in the organic matter At the beginning of the Magellanicum bog stage, 1000 BP, the nitrogen accumulation rate increased from an earlier value of ca 0.4 g m–2 yr–1 to 0.8 g m–2 yr–1 These accumulation rates for N have been used to establish time scales for the periods between the 14C‐datingsThe estimated litter deposition rate in the hummocks is 120 g m–2 yr–1 in the two older bog stages and 270 g m–2 yr–1 in the Magellanicum bog stage The decay losses in the acrotelm increased, as a proportion of the addition, with time through each one of the bog stages The range of variation in the cores for the acrotelm decay losses was 25‐80%. and the annual input of organic matter to the catotelm, 30‐130 g m–2 These ranges are greater than those found among recent bog hummocks in NW Europe and North America The decay losses during 5000 yr in the catotelm may not have exceeded 20% of the original input The over‐all net rate of accumulation of C was highest, ca 40 g m–2 yr–1, at the beginning of the Fuscum bog stageThe changes in the macrofossil assemblages are all associated with rapid increases in the peat accumulation rate, but decreases in accumulation rate are not At the conversion from fen to bog the increased input of organic matter to the catotelm depended on expansion of Sphagnum fuscum which formed a decay resistant litter Later increases depended on rapid rises of the mean water table, resulting in shorter residence times and smaller decay losses from the acrotelm The periods of decreases in input of organic matter to the catotelm depended on longer residence times in the acrotelm when the water table fell relative to the bog surface However, comparisons with recent conditions suggest that the variation in mean water level relative to the surface may not have exceeded 10‐15 cm
Insular patterns of calicioid lichens in a boreal old‐growth forest‐wetland mosaic
Authors: Kruys Nicholas , Jonsson Bengt Gunnar 
Published: July 2006

Fragmentation of the forested landscape poses a threat to many aspects of biodiversity associated with old‐growth forests Studies of the effects of forest fragmentation are often complicated by the variation in composition and age of patches and the matrix This study used a system of isolated stands where patch age and composition were similar and the matrix variability negligible The patches were composed of old‐growth Picea abies stands of varying size and shape in a wetland matrix The study organisms were epiphytic crustose calicioid lichens (also known as Caliciales), many of which are very substrate‐specific and restricted to old‐growth stands The aim of the study was to measure the effect of patch size, patch isolation, habitat and substrate quality on the species riochness and composition of epiphytic calicioids Twenty‐four patches ranging from 0 4 to 15 9 ha in size were studied All species of calicioid lichens were registered in 0 1 ha plots in each patch Isolation was measured as the percentage of available habitat within 400 m of a patch Twenty‐two species were found with an average of 9 48 ± 0 26 (SE) species per patch and 292 ± 0 18 (SE) species per tree Species richness at patch level correlated with stand structure, primarily tree density, while number of species per tree (reflecting population size) was strongly correlated with island size and several stand variables There was no effect of isolation on species richness Species composition was influenced by both substrate variables and patch size The species composition on the islands showed a significant nestedness, i e species composition on species‐poor islands constituted a non‐random subset of the species composition on species‐rich islandsWe propose that the explanation for the strong relationship between species richness at tree level and stand size is an edge effect which implies that unaffected interior areas only occur on large islands The different microclimate of the patch edge enables only the hardiest species to establish large populations there whilst shade and moisture demanding species are restricted to the interiors of larger islands
Correlation between endemism and local ecoclimatic stability documented by comparing Andean bird distributions and remotely sensed land surface data
Authors: Fjeldså Jon , Lambin Eric , Mertens Benoit 
Published: July 2006

Fjeldså, J., Lambin, E, and Mertens, B. 1999, Correlation between endemism and local ecoclimatic stability documented by comparing Andean bird distributions and remotely sensed land surface data. ‐ Ecography 22: 63‐78.Relationships between large‐scale patterns of biodiversity and ecoclimatic variability were examined using distributions of 789 Andean birds, recorded in 15’x 15’grid cells, and interannual differences in Normalized Difference Vegetation Index and Brightness Surface Temperature, calculated month by month and resampled to 15’cells. Following the east Andean treeline from 1°N to 18°S, there is no evidence of a latitudinal gradient in species richness, but a considerable local variation reflecting the habitat complexity in individual cells. The mean endemism (inverse range‐size for all species present in a given cell) shows well marked peaks. Pairwise comparisons of‘peaks’and adjacent‘lows’of endemism provide strong evidence for linking peaks of endemism with local ecoclimatic stability. The most important single factor responsible for this correlation could be orographic moderation of the impacts a south polar winds. Presently manifested as occasional winter freezes in the southern part of the tropical zone, these winds may have been a major determinant of vegetational changes during Pleistocene glacial periods. The correlations suggest that most endemics are relict populations which survived periods of global climatic change in places where these impacts were moderated. It is suggested that, by retaining relict populations, these places play a significant role in the recruitment to the regional species pool. The stable places were also centres of Andean cultures and have dense human populations. The current conservation strategy of reserving areas with few people therefore needs to be supplemented with actions to secure sustainable landuse in certain densely populated areas.
Latitudinal gradients in species diversity and Rapoport's rule revisited: a review of recent work and what can parasites teach us about the causes of the gradients?
Authors: Rohde Klaus 
Published: July 2006

A review is given of recent work on latitudinal gradients in species diversity and their explanations, including Rapoport's rule. Energy input, measured by temperature or potential evapotranspiration. correlates best with the gradients. However, such a correlation does not “explain” them. It merely suggests explanations, which may be either different ceilings to diversity set by different energy levels under equilibrium conditions, recent historical events, or a gradient in effective evolutionary time (determined by speed of evolution directly driven by temperature, and by relative constancy of conditions over evolutionary time) under non‐equilibrium conditions. Marine parasites are used to show that equilibrium conditions are the exception rather than the rule among animals, It is concluded that latitudinal gradients in species diversity result from a gradient in effective evolutionary time modulated by several other factors. Dispersal abilities of many marine invertebrates are likely to be greater at low than at high latitudes, suggesting an opposite Rapppoport effect.This is an invited Minireview on the occasion of the 50th anniversary of the Nordic Ecological Society Oikos.
Occurrence of epiphytic macrolichens in relation to tree species and age in managed boreal forest
Authors: Uliczka Helen , Angelstam Per 
Published: July 2006

For the maintenance of biodiversity some epiphytic macrolichens have been used to identify forests with high conservation value. To understand what these macrolichens indicate, we studied the relationships of tree species and age with the abundance of a set of 33 macrolichens (20 of them in use as indicator species) at 90 localities in a 150 km2area in south‐central Sweden.We sampled the four most common tree species Scots pinePinus sylvestris.Norway sprucePicea abies, birchBetulaspp, and aspenPopulus tremulafor macrolichens at 0‐2 m from the base. Of the 33 target species we found 17, six of them were indicators in use for this region. In 30, out of 40 tested, cases there was a positive relation between lichen abundance and age of the tree.On all tree species the number of the studied lichen species increased with age. The colonisation rate of the species was fastest on birch. All species occurring on birch were also found on at least one of the coniferous trees, while aspen had six species not found on other trees. Pine and spruce with a slow growth rate had more signal lichen species than fast growing trees.We could not detect a competitive situation between common and rare species as the most abundant or largest lichens did not exclude other species. The length of the longest fruticose lichen was positively correlated with the number of species on the tree. Shade had a negative effect on the number of species.We conclude that the indicator macrolichens encountered in this study showed a preference for old trees or aspens. This result, and the low number of indicator species, points at the importance of promoting these trees for the preservation of biodiversity in the boreal forest.
Leaf litter and the small‐scale distribution of carabid beetles (Coleoptera, Carabidae) in the boreal forest
Authors: Koivula. Matti , Punttila. Pekka , Haila Yrjö , Niemelä Jari 
Published: July 2006

Management practices favoring conifers at the expense of deciduous tree species, and the eradication of deciduous trees, especially aspen Populus tremula, from managed forests have resulted in population declines in several species in Fennoscandia. In addition to species depending on decaying wood of deciduous trees, earlier evidence suggests that leaf litter, especially that of aspen, is favored by many carabid species. We ran a four‐year experiment in order to compare carabid assemblages of unchanged forest floor with artificially created leaf‐litter plots in central Finland. A total of 18 plots (5 m in diameter) were established in three forest stands without aspen a few kilometers apart. Each stand had 3 litter plots (litter added) and 3 control plots, Pre‐treatment samples were compared with those collected alter litter addition.The litter addition affected the carabid‐assemblage structure by increasing the catches of some species and decreasing the catch of one species. The number of carabid species was similar in control and litter plots. The litter effect was smaller than variation among forest stands and year‐lo‐year fluctuations. There was a strong temporal constancy among the plots: ‘rich’ plots remained ‘rich’ from year to year and similarly, ‘poor’ plots remained ‘poor’.The significant influence of leaf litter on carabid abundance can be attributable to both abiotic factors (microenvironmental conditions, especially humidity and temperature), and biotic ones (changes in niche structure, improved food supply). Leal litter seems to have an effect on carabid distribution patterns, and deciduous trees scattered among conifers are likely to be of importance on carabid fauna in boreal forests.
Reproductive timing in three southern Appalachian stream fishes
Authors: DeHaven J. E. , Stouder D. J. , Ratajczak R. , Welch T. J. , Grossman G. D. 
Published: July 2006

AbstractWe quantified the reproductive biology of mottled sculpin (Cottus bairdi), rosyside dace (Clinostomus funduloides) and longnose dace (Rhinichthus cataractae) in Coweeta Creek, North Carolina, USA, a fifth order stream. These species are abundant in coldwater streams through out the southern Appalachian mountains, the southernmost limit of their range. We collected fishes from Coweeta Creek every second month (between July 1984 and January 1986) and quantified the seasonal reproductive cycles of females, using both histological techniques and the relative gonadal index (RGI). Both techniques indicated that I) C. bairdi reproduced between March and May, 2) CI. funduloides spawned between May and August and 3) R. cataractae were reproductively active between June and July. These conclusions were supported by the following: 1) the presence of reproductive coloration, 2) gravid females, 3) courtship displays, 4) the presence of nest‐guarding C. bairdi males and 5) the timing of young‐of‐the‐year recruitment. The reproductive characteristics of these 3 species were correlated with different environmental variables. The mean monthly RGI values for both C. bairdi and R. cataractae were inversely correlated with both maximum and minimum daily water temperatures. The mean RGI values for C. bairdi also were negatively correlated with photoperiod, whereas the values for R. cataractae and CI. funduloides were positively correlated with the change in daily photo period.
Movement of brook trout (Salvelinus fontinalis) in four small subalpine streams in northern Colorado
Authors: Riley S. C. , Fausch K. D. , Gowan C. 
Published: July 2006

AbstractWe studied the movement of brook trout (Salvelinus fontinalis) in four small streams in northern Colorado using mark‐recapture methods and weirs. The recapture rates of marked adult trout were low for all streams, and large numbers of unmarked adult trout, apparently immigrants, were found each year. Significantly more trout, immigrated into sections that were experimentally modified by installing low log dams, which increased depth, pool volume and the amount of overhead cover. The number of immigrant and resident trout was significantly related to the amount of cover in the sections. Resident trout were larger than immigrants in all streams in the last year of sampling. Most mobile brook trout moved upstream during summer on the two streams where weirs were operated, and upstream migrants were significantly larger than downstream migrants on both streams. We suggest that a high degree of movement may be an adaptive response by brook trout to the heterogeneous nature of small mountain streams.
Annual variations in the diet of juvenile chinook salmon (Oncorhynchus tshawytscha) in the Waitaki River and the demonstration channels, 1982–1986
Authors: Rutledge M. J. , Power G. 
Published: July 2006

AbstractThe numbers of particular prey in stomach samples of juvenile chinook salmon varied between sites, months and years in two controlled flow demonstration channel sites and the mainstem lower Waitaki River. During 4 growing seasons, 1982–1986, Deleatidium, Aoteapsyche, Hydroptilidae, Elmidae, Chironomidae and Amphipoda were important components of the diet. Salmon also ate a variety of other items of aquatic and terrestrial origin. Diets were quite similar and tended to change in the same way in all sites simultaneously, perhaps in response to discharge. Smaller prey (Chironomidae, Hydroptilidae and early instar Aoteapsyche) were more numerous in stomach samples in seasons of lower, more stable, discharge. Fewer but larger prey were consumed during high flows. The salmon sampled in March 1986 originated from the high egg deposition of 1985 and grew during a season of low discharge. They were exceptionally small and their diet consisted of large numbers of small prey. There was no evidence of progressive annual changes in the habitat or the diet of salmon in the demonstration channels. However, it would be prudent to arrange for flow fluctuations that would be sufficient to flush finer substrate sediments in a controlled flow residual river, thus maintaining the diversity of prey for juvenile salmon.
Within‐stock variations of life‐history traits in juvenile Atlantic salmon (Salmo salar)
Authors: Prévost E. , Chadwick E. M. P. , Claytor R. R. 
Published: July 2006

AbstractVariations in space (geographical location) and time (year) of phenotypic traits linked to life‐history (size, growth, condition and sexual maturation) were analysed within the population of Atlantic salmon (Salmo salar L.) 1 + parr of Little Codroy River (southwest Newfoundland). The hydrographic system was divided into 10 zones: 4 for the mainstem and 6 for the tributaries. Despite the small size of the river studied, a highly significant spatial heterogeneity was observed. Within the mainstem, size, growth and rate of maturation of males tended to decrease when progressing upstream. When compared with the tributaries as a whole, the mainstem had smaller salmon juveniles, both at the end of the first winter (mainstem: 67.6 mm; tributaries: 73.3 mm) and at 1 + age (mainstem: 80.6 mm; tributaries: 88.3 mm), and the proportion of maturing fish among 1 + males was lower (mainstem: 48.6%; tributaries: 74.2%). According to the feature considered, from 20% to 70% of the spatial effect was due only to differences between the mainstem and the tributaries as a whole. A strong year effect was also revealed. Life‐history traits seemed to fluctuate over time independently from one tributary to another, whereas patterns in their yearly variations were basically consistent among zones in the mainstem. The potential role of genetic and environmental factors in explaining changes in space and time of biological characteristics of parr is discussed. Within a small system such as Little Codroy River, spatio‐temporal life‐history variations of Atlantic salmon juveniles were most likely driven by environment.
Growth and mortality of juvenile sunfishes (Lepomis sp.) under heavy predation
Authors: Belk M. C. 
Published: July 2006

AbstractThe relationship among growth, energy storage and mortality of juvenile bluegills (Lepomis macrochirus, Rafinesque) experiencing heavy predation was experimentally investigated in a large reservoir where piscivorous largemouth bass (Micropterus salmoides, Lacépède) were abundant. I conducted experiments evaluating interspecific competition, density‐dependent growth and lipid content and habitat‐specific growth and mortality rates of juvenile bluegills in this reservoir. Enclosure experiments showed that the growth rates of bluegills were unaffected by presence of other Lepomis species but decreased with increasing bluegill density. However, at densities corresponding to those found in the reservoir, the growth rates of bluegills were high, and competition appeared to be relatively unimportant. The percentage lipid content of bluegills was unaffected by the presence of other species, density of bluegills or habitat. The growth rates of bluegills in vegetated refuge areas were significantly higher and mortality rates were significantly lower compared with open water habitats. The low densities and high growth rates of juvenile bluegills in refuge environments suggests that there is a strong lethal effect of predators on this population of bluegills.