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Conifer Forests (conifer + forest)
Kinds of Conifer Forests Selected AbstractsThresholds in landscape connectivity and mortality risks in response to growing road networksJOURNAL OF APPLIED ECOLOGY, Issue 5 2008Jacqueline L. Frair Summary 1The ecological footprint of a road may extend for several kilometres with overlapping effects from neighbouring roads causing a nonlinear accumulation of road effects in the landscape. Availability of preferred habitat, spatial dependencies between roads and habitat types, and fidelity to traditionally used areas further confound our ability to predict population-level responses of animals to growing road networks. 2To isolate these effects, we developed an individually based movement model using elk Cervus elaphus L. as a model system. Empirically derived movement rules redistributed elk under different amounts of preferred habitat (clearcuts), road densities, and road development schemes. We tracked potential mortality risk (given time spent near roads) and emigration rates (given declining accessibility of foraging habitat). 3Design of the road network accounted for up to 30,55% difference in mortality risk and emigration rates, with the largest differences occurring at intermediate road densities (1,1·5 km km,2) when road effects began to saturate the landscape. Maintaining roads in association with clearcuts caused a decline in habitat accessibility equivalent to replacing 50,75% of these foraging patches with conifer forest. A nine-fold difference in potential emigration was observed after varying elk tolerance for declining habitat accessibility despite holding local movement biases constant. 4Elk responses to growing road networks were non-linear, exposing thresholds for road density that were reflected in the home range occupancy patterns of a large sample of elk in the region. 5Synthesis and applications. Our approach provides a means of scaling-up complex movement decisions to population-level redistribution, separating the confounding effects of landscape context from road effects, and exposing thresholds in connectivity and mortality risks for wildlife caused by infrastructure growth. Our model indicated that road densities , 0·5 km km,2 yielded the highest probability of elk occurrence where elk were hunted (and sensitive to roads), but disassociating roads from foraging habitats or managing human access to roads may maintain effective elk habitat at substantially higher road densities. [source] Using GIS to relate small mammal abundance and landscape structure at multiple spatial extents: the northern flying squirrel in Alberta, CanadaJOURNAL OF APPLIED ECOLOGY, Issue 3 2005MATTHEW WHEATLEY Summary 1It is common practice to evaluate the potential effects of management scenarios on animal populations using geographical information systems (GIS) that relate proximate landscape structure or general habitat types to indices of animal abundance. Implicit in this approach is that the animal population responds to landscape features at the spatial grain and extent represented in available digital map inventories. 2The northern flying squirrel Glaucomys sabrinus is of particular interest in North American forest management because it is known from the Pacific North-West as a habitat specialist, a keystone species of old-growth coniferous forest and an important disperser of hypogeous, mycorrhizal fungal spores. Using a GIS approach we tested whether the relative abundance of flying squirrel in northern Alberta, Canada, is related to old forest, conifer forest and relevant landscape features as quantified from management-based digital forest inventories. 3We related squirrel abundance, estimated through live trapping, to habitat type (forest composition: conifer, mixed-wood and deciduous) and landscape structure (stand height, stand age, stand heterogeneity and anthropogenic disturbance) at three spatial extents (50 m, 150 m and 300 m) around each site. 4Relative abundances of northern flying squirrel populations in northern and western Alberta were similar to those previously reported from other regions of North America. Capture rates were variable among sites, but showed no trends with respect to year or provincial natural region (foothills vs. boreal). 5Average flying squirrel abundance was similar in all habitats, with increased values within mixed-wood stands at large spatial extents (300 m) and within deciduous-dominated stands at smaller spatial extents (50 m). No relationship was found between squirrel abundance and conifer composition or stand age at any spatial extent. 6None of the landscape variables calculated from GIS forest inventories predicted squirrel abundance at the 50-m or 150-m spatial extents. However, at the 300-m spatial extent we found a negative, significant relationship between average stand height and squirrel abundance. 7Synthesis and applications. Boreal and foothill populations of northern flying squirrel in Canada appear unrelated to landscape composition at the relatively large spatial resolutions characteristic of resource inventory data commonly used for management and planning in these regions. Flying squirrel populations do not appear clearly associated with old-aged or conifer forests; rather, they appear as habitat generalists. This study suggests that northern, interior populations of northern flying squirrel are probably more related to stand-level components of forest structure, such as food, microclimate (e.g. moisture) and understorey complexity, variables not commonly available in large-scale digital map inventories. We conclude that the available digital habitat data potentially exclude relevant, spatially dependent information and could be used inappropriately for predicting the abundance of some species in management decision making. [source] Spatial synchrony in field vole Microtus agrestis abundance in a coniferous forest in northern England: the role of vole-eating raptorsJOURNAL OF APPLIED ECOLOGY, Issue 2000S.J. Petty 1.,The regional synchrony hypothesis (RSH) states that synchrony in microtine abundance over large geographical areas is caused by nomadic avian predators that specialize on small mammals for food. This has proved a difficult hypothesis to test because experiments at an appropriate scale are almost impossible. 2.,We used the decline of the most abundant, nomadic vole-eating raptors in an extensive conifer forest in northern England (Kielder Forest) as a natural experiment to evaluate their influence on synchronizing voles at different spatial scales. Field vole populations fluctuated on a 3,4-year cycle of abundance, similar to the periodicity in central Fennoscandia. 3.,Over a 23-year period, the combined numbers and density of kestrels and short-eared owls significantly declined. If these raptors were responsible for synchronizing vole abundance, the decline should have been associated with a decrease in synchrony. We could find no change in synchrony during the period of the greatest decline in kestrel and short-eared owl numbers (1980,97). 4.,In Kielder, vole abundance has been shown to change in a wave-like manner, with synchrony in the direction of the wave being 5,10-fold smaller than that reported in Fennoscandia. Tawny owls are sedentary and the most abundant vole-eating raptor in our study area, and might have an equalizing influence on vole abundance over smaller areas if they foraged in a density-dependent manner and responded functionally to increasing vole density. If this was the case, spatial variability in vole density should have been less in occupied than unoccupied owl territories, especially in years of low vole density when owls could take a larger proportion of the standing crop of voles. Even though tawny owls caught a significant proportion of the vole population, we could find no difference in variation in vole density between owl territories that were unoccupied, occupied with no breeding attempt, or occupied with a successful breeding attempt. 5.,We conclude that the small-scale synchrony in field vole abundance is unlikely to be caused by avian predators. Instead, it is more likely to be related to the pattern of clear-cutting that has developed in Kielder, which restricts vole dispersal. If this assumption is correct, we would predict more widespread synchrony in vole abundance in first-generation forests when extensive areas are planted over short periods of time, and this is supported by anecdotal evidence. These conclusions indicate that foresters may be able to manipulate the spatial dynamics of voles and vole predators by varying patch sizes within forests. [source] Effects of ecogeographic variables on genetic variation in montane mammals: implications for conservation in a global warming scenarioJOURNAL OF BIOGEOGRAPHY, Issue 7 2007Amy M. Ditto Abstract Aim, Evolutionary theory predicts that levels of genetic variation in island populations will be positively correlated with island area and negatively correlated with island isolation. These patterns have been empirically established for oceanic islands, but little is known about the determinants of variation on habitat islands. The goals of this study were twofold. Our first aim was to test whether published patterns of genetic variation in mammals occurring on montane habitat islands in the American Southwest conformed to expectations based on evolutionary theory. The second aim of this research was to develop simple heuristic models to predict changes in genetic variation that may occur in these populations as a result of reductions in available mountaintop habitat in response to global warming. Location, Habitat islands of conifer forest on mountaintops in the American Southwest. Methods, Relationships between island area and isolation with measures of allozyme variation in four species of small mammal, namely the least chipmunk (Tamias minimus), Colorado chipmunk (Tamias quadrivittatus), red squirrel (Tamiasciurus hudsonicus), and Mexican woodrat (Neotoma mexicana), were determined using correlation and regression techniques. Significant relationships between island area and genetic variation were used to develop three distinct statistical models with which to predict changes in genetic variation following reduction in insular habitat area arising from global warming. Results, Patterns of genetic variation in each species conformed to evolutionary predictions. In general, island area was the most important determinant of heterozygosity, while island isolation was the most important determinant of polymorphism and allelic diversity. The heuristic models predicted widespread reductions in genetic variation, the extent of which depended on the population and model considered. Main conclusions, The results support a generalized pattern of genetic variation for any species with an insular distribution, with reduced variation in smaller, more isolated populations. We predict widespread reductions in genetic variation in isolated populations of montane small mammals in the American Southwest as a result of global warming. We conclude that climate-induced reductions in the various dimensions of genetic variation may increase the probability of population extinction in both the short and long term. [source] Spatial and temporal variation of fire regimes in a mixed conifer forest landscape, Southern Cascades, California, USAJOURNAL OF BIOGEOGRAPHY, Issue 8 2001R. Matthew Beaty Aim In this study, we evaluated the fire-forest mosaic of a mixed conifer forest landscape by testing the hypothesis that pre-fire suppression fire regime parameters vary with species composition (tree species), and environment (i.e. slope aspect, slope position, elevation). Location Our study was conducted in the 1587 ha Cub Creek Research Natural Area (CCRNA), Lassen National Forest, CA, USA. Methods We quantified the return interval, seasonal occurrence, size, rotation period, and severity of fires using dendroecology. Results Slope aspect, potential soil moisture, forest composition, and fire regime parameters in our study area co-vary. Median composite and point fire return intervals (FRI) were longest on higher, cooler, more mesic, north-facing (NF) slopes covered with white fir (Abies concolor), Douglas fir (Pseudotsuga menziesii),white fir, and red fir (A. magnifica),white fir forests, shortest on the dry, south-facing (SF) slopes covered with ponderosa pine (Pinus ponderosa),white fir forests and intermediate on west-facing slopes dominated by white fir,sugar pine (P. lambertiana),incense cedar (Libocedrus decurrens) forests. The spatial pattern for length of fire rotation (FR) was the same as that for FRI. Fires in CCRNA mixed conifer forests occurred mainly (90%) in the dormant season. Size of burns in CCRNA mixed conifer forests were generally small (mean=106 ha), however, during certain drought years widespread fires burned across fuel breaks and spread throughout the watershed. Fire severity was mainly high on upper slopes, low on lower slopes and moderate and low severity on middle slopes. Patterns of fire severity also varied with slope aspect. Fire frequency decreased dramatically in CCRNA after 1905. Conclusions In CCRNA, fire regime parameters [e.g. FRI, fire extent, FR, fire severity] varied widely with species composition, slope aspect and slope position. There was also temporal variation in fire extent with the most widespread fires occurring during drought years. The important contributions of topography and climate to variation in the fire regime indicates that exogenous factors play a key role in shaping the fire-forest structure mosaic and that the fire-forest structure mosaic is more variable, less predictable and less stable than previously thought. Finally, some characteristics of the fire regime (i.e. fire severity, season of burn) in CCRNA are different than those described for other mixed conifer forests and this suggests that there are geographical differences in mixed conifer fire regimes along the Pacific slope. [source] Carbon Sequestration in Two Alpine Soils on the Tibetan PlateauJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2009Yu-Qiang Tian Abstract Soil carbon sequestration was estimated in a conifer forest and an alpine meadow on the Tibetan Plateau using a carbon-14 radioactive label provided by thermonuclear weapon tests (known as bomb- 14C). Soil organic matter was physically separated into light and heavy fractions. The concentration spike of bomb- 14C occurred at a soil depth of 4 cm in both the forest soil and the alpine meadow soil. Based on the depth of the bomb- 14C spike, the carbon sequestration rate was determined to be 38.5 g C/m2 per year for the forest soil and 27.1 g C/m2 per year for the alpine meadow soil. Considering that more than 60% of soil organic carbon (SOC) is stored in the heavy fraction and the large area of alpine forests and meadows on the Tibetan Plateau, these alpine ecosystems might partially contribute to "the missing carbon sink". [source] Fire and vegetation history on Santa Rosa Island, Channel Islands, and long-term environmental change in southern California,JOURNAL OF QUATERNARY SCIENCE, Issue 5 2010R. Scott Anderson Abstract The long-term history of vegetation and fire was investigated at two locations , Soledad Pond (275,m; from ca. 12 000,cal. a BP) and Abalone Rocks Marsh (0,m; from ca. 7000,cal. a BP) , on Santa Rosa Island, situated off the coast of southern California. A coastal conifer forest covered highlands of Santa Rosa during the last glacial, but by ca. 11 800,cal. a BP Pinus stands, coastal sage scrub and grassland replaced the forest as the climate warmed. The early Holocene became increasingly drier, particularly after ca. 9150,cal. a BP, as the pond dried frequently, and coastal sage scrub covered the nearby hillslopes. By ca. 6900,cal. a BP grasslands recovered at both sites. Pollen of wetland plants became prominent at Soledad Pond after ca. 4500,cal. a BP, and at Abalone Rocks Marsh after ca. 3465,cal. a BP. Diatoms suggest freshening of the Abalone Rocks Marsh somewhat later, probably by additional runoff from the highlands. Introduction of non-native species by ranchers occurred subsequent to AD 1850. Charcoal influx is high early in the record, but declines during the early Holocene when minimal biomass suggests extended drought. A general increase occurs after ca. 7000,cal. a BP, and especially after ca. 4500,cal. a BP. The Holocene pattern closely resembles population levels constructed from the archaeological record, and suggests a potential influence by humans on the fire regime of the islands, particularly during the late Holocene. Copyright © 2009 John Wiley & Sons, Ltd. [source] Fire disturbance and forest structure in old-growth mixed conifer forests in the northern Sierra Nevada, CaliforniaJOURNAL OF VEGETATION SCIENCE, Issue 6 2007R. Matthew Beaty Abstract Question: This study evaluates how fire regimes influence stand structure and dynamics in old-growth mixed conifer forests across a range of environmental settings. Location: A 2000-ha area of mixed conifer forest on the west shore of Lake Tahoe in the northern Sierra Nevada, California. Methods: We quantified the age, size, and spatial structure of trees in 12 mixed conifer stands distributed across major topographic gradients. Fire history was reconstructed in each stand using fire scar dendrochronology. The influence of fire on stand structure was assessed by comparing the fire history with the age, size, and spatial structure of trees in a stand. Results: There was significant variation in species composition among stands, but not in the size, age and spatial patterning of trees. Stands had multiple size and age classes with clusters of similar aged trees occurring at scales of 113 - 254 m2. The frequency and severity of fires was also similar, and stands burned with low to moderate severity in the dormant season on average every 9,17 years. Most fires were not synchronized among stands except in very dry years. No fires have burned since ca. 1880. Conclusions: Fire and forest structure interact to perpetuate similar stand characteristics across a range of environmental settings. Fire occurrence is controlled primarily by spatial variation in fuel mosaics (e.g. patterns of abundance, fuel moisture, forest structure), but regional drought synchronizes fire in some years. Fire exclusion over the last 120 years has caused compositional and structural shifts in these mixed conifer forests. [source] Intra- and Interannual Vegetation Change: Implications for Long-Term ResearchRESTORATION ECOLOGY, Issue 1 2008Julie E. Korb Abstract To draw reliable conclusions from forest restoration experiments, it is important that long-term measurements be repeatable or year-to-year variability may interfere with the correct interpretation of treatment effects. We used permanent plots in a long-term restoration study in southwestern Colorado to measure herbaceous and shrub vegetation at three dates within a single year (June, July, and August), and between years (2003 and 2005), on untreated control plots in a warm, dry mixed conifer forest. Growing season precipitation patterns were similar between 2003 and 2005, so differences in vegetation should be related primarily to differences in the sampling month. Significant indicator species for each sampling month were present within a single year (2005), primarily reflecting early-season annuals. We found no significant differences for total species abundance (2005). Species richness, abundance, and indicator species were significantly different between years for different sampling months indicating that sampling should be conducted within a similar time frame to avoid detecting differences that are not due to treatment effects or variations in year-to-year climate. These findings have implications for long-term research studies where the objectives are to detect changes over time in response to treatments, climate variation, and natural processes. Long-term sampling should occur within a similar phenological time frame each year over a short amount of time and should be based on the following criteria: (1) the sampling period is congruent with research objectives such as detecting rare species or peak understory abundance and (2) the sampling period is feasible in regard to personnel and financial constraints. [source] Modeling above-ground litterfall in eastern Mediterranean conifer forests using fractional tree cover, and remotely sensed and ground dataAPPLIED VEGETATION SCIENCE, Issue 4 2010Sibel Taskinsu-Meydan Abstract Question: How can we model above-ground litterfall in Mediterranean conifer forests using remotely sensed and ground data, and geographic information systems (GIS)? Location: Eastern Mediterranean conifer forest of Turkey. Methods: Above-ground litterfall from Mediterranean forest stands of Pinus nigra, Cedrus libani, Pinus brutia and Juniperus excelsa and mixed Abies cilicica, C. libani and P. nigra was modeled as a function of fractional tree cover using a regression tree algorithm, based on IKONOS and Landsat TM/ETM+data. Landsat TM/ETM+images for the study area were used to map actual stand patterns, based on a land-cover map of species stands using a supervised classification. Results: Total amount of annual above-ground litterfall for the entire study area (12 260 km2) was estimated at 417.2 Mg ha,1 for P. brutia, 291.1 Mg ha,1 for the mixed stand, 115.5 Mg ha,1 for P. nigra, 54.6 Mg ha,1 for J. excelsa and 45.9 Mg ha,1 for C. libani. The maps generated indicate the distribution of the seasonal amount of total above-ground litterfall for different species and the distribution of species stands in the study area. There was an increase in the amount of above-ground litterfall for P. brutia stand in summer, for J. excelsa in autumn and for C. libani, P. nigra and the mixed stand of A. cilicica, P. nigra and C. libani in winter. Conclusion: Application of this model helps to improve the accuracy of estimated litterfall input to soil organic carbon pools in the Mediterranean conifer forests. [source] Modeling landscape patterns of understory tree regeneration in the Pacific Northwest, USAAPPLIED VEGETATION SCIENCE, Issue 2 2001Michael C. Wimberly Abstract. Vegetation maps serve as the basis for spatial analysis of forest ecosystems and provide initial information for simulations of forest landscape change. Because of the limitations of current remote sensing technology, it is not possible to directly measure forest understory attributes across large spatial extents. Instead we used a predictive vegetation mapping approach to model Tsuga heterophylla and Picea sitchensis seedling patterns in a 3900-ha landscape in the Oregon Coast Range, USA, as a function of Landsat TM imagery, aerial photographs, digital elevation models, and stream maps. Because the models explained only moderate amounts of variability (R2 values of 0.24,0.56), we interpreted the predicted patterns as qualitative spatial trends rather than precise maps. P. sitchensis seedling patterns were tightly linked to the riparian network, with highest densities in coastal riparian areas. T. heterophylla seedlings exhibited complex patterns related to topography and overstory forest cover, and were also spatially clustered around patches of old-growth forest. We hypothesize that the old growth served as refugia for this fire-sensitive species following wildfires in the late 19th and early 20th centuries. Low levels of T. heterophylla regeneration in hardwood-dominated forests suggest that these patches may succeed to shrublands rather than to conifer forest. Predictive models of seedling patterns could be developed for other landscapes where georeferenced inventory plots, remote sensing data, digital elevation models, and climate maps are available. [source] Spread and impact of introduced conifers in South America: Lessons from other southern hemisphere regionsAUSTRAL ECOLOGY, Issue 5 2010DANIEL SIMBERLOFF Abstract The history of conifers introduced earlier elsewhere in the southern hemisphere suggests that recent invasions in Argentina, Brazil, Chile and Uruguay are likely to increase in number and size. In South Africa, New Zealand and Australia, early ornamental introductions and small forestry plantations did not lead to large-scale invasions, while subsequent large plantations were followed with a lag of about 20,30 years by troublesome invasions. Large-scale conifer plantation forestry in South America began about 50,80 years later than in South Africa, Australia and New Zealand, while reports of invasions in South America lagged behind those in the latter nations by a century. Impacts of invading non-native conifers outside South America are varied and include replacement of grassland and shrubland by conifer forest, alteration of fire and hydrological regimes, modification of soil nutrients, and changes in aboveground and belowground biotic communities. Several of these effects have already been detected in various parts of South America undergoing conifer invasion. The sheer amount of area planted in conifers is already very large in Chile and growing rapidly in Argentina and Brazil. This mass of reproductive trees, in turn, produces an enormous propagule pressure that may accelerate ongoing invasions and spark new ones at an increasing rate. Regulations to control conifer invasions, including measures to mitigate spread, were belatedly implemented in New Zealand and South Africa, as well as in certain Australian states, inspired by observations on invasions in those nations. Regulations in South America are weaker and piecemeal, but the existing research base on conifer invasions elsewhere could be useful in fashioning effective regulations in South America. Pressure from foreign customers in South Africa has led most companies there to seek certification through the Forestry Stewardship Council; a similar programme operates in Australia. Such an approach may be promising in South America. [source] Litterfall dynamics and nitrogen use efficiency in two evergreen temperate rainforests of southern ChileAUSTRAL ECOLOGY, Issue 6 2003CECILIA A. PEREZ Abstract In unpolluted regions, where inorganic nitrogen (N) inputs from the atmosphere are minimal, such as remote locations in southern South America, litterfall dynamics and N use efficiency of tree species should be coupled to the internal N cycle of forest ecosystems. This hypothesis was examined in two evergreen temperate forests in southern Chile (42°30'S), a mixed broad-leaved forest (MBF) and a conifer forest (CF). Although these forests grow under the same climate and on the same parental material, they differ greatly in floristic structure and canopy dynamics (slower in the CF). In both forests, biomass, N flux, and C/N ratios of fine litterfall were measured monthly from May 1995 to March 1999. There was a continuous litter flux over the annual cycle in both forests, with a peak during autumn in the CF. In the MBF, litterfall decreased during spring. In both forests, the C/N ratios of litterfall varied over the annual cycle with a maximum in autumn. Annual litterfall biomass flux (Mean ± SD = 3.3 ± 0.5 vs 2.0 ± 0.5 Mg ha -1) and N return (34.8 ± 16 vs 9.1 ± 2.8 kg N ha -1) were higher in the MBF than in the CF. At the ecosystem level, litterfall C/N was lower in the MBF (mean C/N ratio = 60.1 ± 15, n= 3 years) suggesting decreased N use efficiency compared with CF (mean C/N ratio = 103 ± 19.6, n= 3 years). At the species level, subordinated (subcanopy) tree species in the MBF had significantly lower C/N ratios (<50) of litterfall than the dominant trees in the CF and MBF (>85). The litterfall C/N ratio and percentage N retranslocated were significantly correlated and were lower in the MBF. The higher net N mineralization in soils of the MBF is related to a lower N use efficiency at the ecosystem and species level. [source] The role of environmental gradients in non-native plant invasion into burnt areas of Yosemite National Park, CaliforniaDIVERSITY AND DISTRIBUTIONS, Issue 2 2006Rob Klinger ABSTRACT Fire is known to facilitate the invasion of many non-native plant species, but how invasion into burnt areas varies along environmental gradients is not well-understood. We used two pre-existing data sets to analyse patterns of invasion by non-native plant species into burnt areas along gradients of topography, soil and vegetation structure in Yosemite National Park, California, USA. A total of 46 non-native species (all herbaceous) were recorded in the two data sets. They occurred in all seven of the major plant formations in the park, but were least common in subalpine and upper montane conifer forests. There was no significant difference in species richness or cover of non-natives between burnt and unburnt areas for either data set, and environmental gradients had a stronger effect on patterns of non-native species distribution, abundance and species composition than burning. Cover and species richness of non-natives had significant positive correlations with slope (steepness) and herbaceous cover, while species richness had significant negative correlations with elevation, the number of years post-burn, and cover of woody vegetation. Non-native species comprised a relatively minor component of the vegetation in both burnt and unburnt areas in Yosemite (percentage species = 4%, mean cover < 6.0%), and those species that did occur in burnt areas tended not to persist over time. The results indicate that in many western montane ecosystems, fire alone will not necessarily result in increased rates of invasion into burnt areas. However, it would be premature to conclude that non-native species could not affect post-fire succession patterns in these systems. Short fire-return intervals and high fire severity coupled with increased propagule pressure from areas used heavily by humans could still lead to high rates of invasion, establishment and spread even in highly protected areas such as Yosemite. [source] Seasonal variation in the energy and water exchanges above and below a larch forest in eastern SiberiaHYDROLOGICAL PROCESSES, Issue 8 2001Takeshi Ohta Abstract The water and energy exchanges in forests form one of the most important hydro-meteorological systems. There have been far fewer investigations of the water and heat exchange in high latitude forests than of those in warm, humid regions. There have been few observations of this system in Siberia for an entire growing season, including the snowmelt and leaf-fall seasons. In this study, the characteristics of the energy and water budgets in an eastern Siberian larch forest were investigated from the snowmelt season to the leaf-fall season. The latent heat flux was strongly affected by the transpiration activity of the larch trees and increased quickly as the larch stand began to foliate. The sensible heat dropped at that time, although the net all-wave radiation increased. Consequently, the seasonal variation in the Bowen ratio was clearly ,U'-shaped, and the minimum value (1·0) occurred in June and July. The Bowen ratio was very high (10,25) in early spring, just before leaf opening. The canopy resistance for a big leaf model far exceeded the aerodynamic resistance and fluctuated over a much wider range. The canopy resistance was strongly restricted by the saturation deficit, and its minimum value was 100 s m,1 (10 mm s,1 in conductance). This minimum canopy resistance is higher than values obtained for forests in warm, humid regions, but is similar to those measured in other boreal conifer forests. It has been suggested that the senescence of leaves also affects the canopy resistance, which was higher in the leaf-fall season than in the foliated season. The mean evapotranspiration rate from 21 April 1998 to 7 September 1998 was 1·16 mm day,1, and the maximum rate, 2·9 mm day,1, occurred at the beginning of July. For the growing season from 1 June to 31 August, this rate was 1·5 mm day,1. The total evapotranspiration from the forest (151 mm) exceeded the amount of precipitation (106 mm) and was equal to 73% of the total water input (211 mm), including the snow water equivalent. The understory evapotranspiration reached 35% of the total evapotranspiration, and the interception evaporation was 15% of the gross precipitation. The understory evapotranspiration was high and the interception evaporation was low because the canopy was sparse and the leaf area index was low. Copyright © 2001 John Wiley & Sons, Ltd. [source] Winter selection of landscapes by woodland caribou: behavioural response to geographical gradients in habitat attributesJOURNAL OF APPLIED ECOLOGY, Issue 5 2008Daniel Fortin Summary 1Understanding animal,habitat relationships is central to the development of strategies for wildlife management and conservation. The availability of habitat attributes often changes along latitudinal and longitudinal axes, and animals may respond to those changes by adjusting their selection. We evaluated whether landscape selection by forest-dwelling woodland caribou Rangifer tarandus caribou varied along geographical gradients in habitat attributes. 2Centroids (n = 422) of track networks made by caribou in winter were recorded during aerial surveys conducted over 161 920 km2 of boreal forest in Québec, Canada. Autologistic models were estimated by comparing the characteristics of landscapes (201 km2) centred on each centroid to an equal number of randomly located landscapes, with an autocovariate controlling for the non-independence among caribou locations. 3The availability of habitat attributes varied along longitudinal and latitudinal gradients, and caribou altered their landscape selection with respect to those gradients. 4Information Theory provided substantial support for only one model. The model revealed that the probability of occurrence of caribou increased with the abundance of conifer forests over most of the study region, but this positive response gradually became negative towards the southern portion of the region. The association between caribou and lichens changed from being negative west of the study region to being positive in the eastern part. Availability of landscapes dominated by lichen decreased from west to east. Finally, caribou generally displayed an aversion to areas with high road density, a negative association that became positive in the southern part of the study region. 5Synthesis and applications. Under current legislation in Canada, the critical habitat of woodland caribou must be defined, and then protected. Our autoregressive models can help to identify landscapes to prioritize conservation efforts. The probability of occurrence of caribou was related to different landscape characteristics across their range, which implies that the typical habitat of woodland caribou differs spatially. Such behavioural plasticity could be problematic for defining critical habitat, but we showed that spatial variation in landscape selection was organized along geographical gradients. Our study illustrates how geographical trends in habitat selection can guide management and conservation decisions. [source] Using GIS to relate small mammal abundance and landscape structure at multiple spatial extents: the northern flying squirrel in Alberta, CanadaJOURNAL OF APPLIED ECOLOGY, Issue 3 2005MATTHEW WHEATLEY Summary 1It is common practice to evaluate the potential effects of management scenarios on animal populations using geographical information systems (GIS) that relate proximate landscape structure or general habitat types to indices of animal abundance. Implicit in this approach is that the animal population responds to landscape features at the spatial grain and extent represented in available digital map inventories. 2The northern flying squirrel Glaucomys sabrinus is of particular interest in North American forest management because it is known from the Pacific North-West as a habitat specialist, a keystone species of old-growth coniferous forest and an important disperser of hypogeous, mycorrhizal fungal spores. Using a GIS approach we tested whether the relative abundance of flying squirrel in northern Alberta, Canada, is related to old forest, conifer forest and relevant landscape features as quantified from management-based digital forest inventories. 3We related squirrel abundance, estimated through live trapping, to habitat type (forest composition: conifer, mixed-wood and deciduous) and landscape structure (stand height, stand age, stand heterogeneity and anthropogenic disturbance) at three spatial extents (50 m, 150 m and 300 m) around each site. 4Relative abundances of northern flying squirrel populations in northern and western Alberta were similar to those previously reported from other regions of North America. Capture rates were variable among sites, but showed no trends with respect to year or provincial natural region (foothills vs. boreal). 5Average flying squirrel abundance was similar in all habitats, with increased values within mixed-wood stands at large spatial extents (300 m) and within deciduous-dominated stands at smaller spatial extents (50 m). No relationship was found between squirrel abundance and conifer composition or stand age at any spatial extent. 6None of the landscape variables calculated from GIS forest inventories predicted squirrel abundance at the 50-m or 150-m spatial extents. However, at the 300-m spatial extent we found a negative, significant relationship between average stand height and squirrel abundance. 7Synthesis and applications. Boreal and foothill populations of northern flying squirrel in Canada appear unrelated to landscape composition at the relatively large spatial resolutions characteristic of resource inventory data commonly used for management and planning in these regions. Flying squirrel populations do not appear clearly associated with old-aged or conifer forests; rather, they appear as habitat generalists. This study suggests that northern, interior populations of northern flying squirrel are probably more related to stand-level components of forest structure, such as food, microclimate (e.g. moisture) and understorey complexity, variables not commonly available in large-scale digital map inventories. We conclude that the available digital habitat data potentially exclude relevant, spatially dependent information and could be used inappropriately for predicting the abundance of some species in management decision making. [source] The fate of an intentional introduction of Formica lugubris to North America from EuropeJOURNAL OF APPLIED ENTOMOLOGY, Issue 4 2008A. J. Storer Abstract Red wood ants (Formica s.str.) are not prevalent in the forests of North America, but commonly occur in conifer and mixed conifer forests in northern Europe and Asia. In 1971, a European red wood ant species, Formica lugubris, was intentionally established in a 35-year-old predominantly mixed conifer plantation approximately 30 km north of QC, Canada. The purpose of its introduction was to evaluate the potential of this species as a biological control agent against conifer-defoliating Lepidoptera species. This red wood ant introduction was monitored periodically for about 5 years after establishment, but its long-term fate has not been reported. We visited this field site in 2005 and found that this species was well established, and we could locate some of the nests that resulted from the original release. We mapped and measured over 100 nests around the site of original release, which ranged from 5 cm in height to over 1 m. We estimated the population of introduced ants to have grown to over 8 million in the last 34 years. Significant clustering of nests suggests that these nests may be one supercolony. F. lugubris has become a dominant understory arthropod in this mixed forest, and is likely to have ecological impacts, including effects at the community and ecosystem level. [source] Influences of climate on fire regimes in montane forests of north-western MexicoJOURNAL OF BIOGEOGRAPHY, Issue 8 2008Carl N. Skinner Abstract Aim, To identify the influence of interannual and interdecadal climate variation on the occurrence and extent of fires in montane conifer forests of north-western Mexico. Location, This study was conducted in Jeffrey pine (Pinus jeffreyi Grev. & Balf.)-dominated mixed-conifer forests in the central and northern plateau of the Sierra San Pedro Mártir, Baja California, Mexico. Methods, Fire occurrence was reconstructed for 12 dispersed sites for a 290-year period (1700,1990) from cross-dated fire-scarred samples extracted from live trees, snags and logs. Superposed epoch analysis was used to examine the relationships of tree-ring reconstructions of drought, the El Niño/Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) with fire occurrence and extent. Results, Years with no recorded fire scars were wetter than average. In contrast, years of widespread fires were dry and associated with phase changes of the PDO, usually from positive (warm) to negative (cold). The influence of the PDO was most evident during the La Niña phase of the ENSO. Widespread fires were also associated with warm/wet conditions 5 years before the fire. We hypothesize that the 5-year lag between warm/wet conditions and widespread fires may be associated with the time necessary to build up sufficient quantity and continuity of needle litter to support widespread fires. Two periods of unusually high fire activity (1770,1800 and 1920,1950) were each followed by several decades of unusually low fire activity. The switch in each case was associated with strong phase changes in both PDO and ENSO. Main conclusions, Climate strongly influences fire regimes in the mountains of north-western Mexico. Wet/warm years are associated with little fire activity. However, these years may contribute to subsequent fire years by encouraging the production of sufficient needle litter to support more widespread fires that occur in dry/cool years. [source] Historical and contemporary distributions of carnivores in forests of the Sierra Nevada, California, USAJOURNAL OF BIOGEOGRAPHY, Issue 8 2005William J. Zielinski Abstract Aim, Mammalian carnivores are considered particularly sensitive indicators of environmental change. Information on the distribution of carnivores from the early 1900s provides a unique opportunity to evaluate changes in their distributions over a 75-year period during which the influence of human uses of forest resources in California greatly increased. We present information on the distributions of forest carnivores in the context of two of the most significant changes in the Sierra Nevada during this period: the expansion of human settlement and the reduction in mature forests by timber harvest. Methods, We compare the historical and contemporary distributions of 10 taxa of mesocarnivores in the conifer forests of the Sierra Nevada and southern Cascade Range by contrasting the distribution of museum and fur harvest records from the early 1900s with the distribution of detections from baited track-plate and camera surveys conducted from 1996 to 2002. A total of 344 sample units (6 track plates and 1 camera each) were distributed systematically across c. 3,000,000 ha area over a 7-year period. Results, Two species, the wolverine (Gulo gulo) and the red fox (Vulpes vulpes), present in the historical record for our survey area, were not detected during the contemporary surveys. The distributions of 3 species (fisher [Martespennanti], American marten [M. americana], and Virginia opossum [Didelphisvirginiana]) have substantially changed since the early 1900s. The distributions of fishers and martens, mature-forest specialists, appeared to have decreased in the northern Sierra Nevada and southern Cascade region. A reputed gap in the current distribution of fishers was confirmed. We report for the first time evidence that the distribution of martens has become fragmented in the southern Cascades and northern Sierra Nevada. The opossum, an introduced marsupial, expanded its distribution in the Sierra Nevada significantly since it was introduced to the south-central coast region of California in the 1930s. There did not appear to be any changes in the distributions of the species that were considered habitat generalists: gray fox (Urocyon cinereoargenteus), striped skunk (Mephitis mephitis), western spotted skunk (Spilogale gracilis), or black bear (Ursus americanus). Detections of raccoons (Procyon lotor) and badgers (Taxidea taxus) were too rare to evaluate. Contemporary surveys indicated that weasels (M. frenata and M. erminea) were distributed throughout the study area, but historical data were not available for comparison. Main conclusions, Two species, the wolverine and Sierra Nevada red fox, were not detected in contemporary surveys and may be extirpated or in extremely low densities in the regions sampled. The distributions of the mature forest specialists (marten and fisher) appear to have changed more than the distributions of the forest generalists. This is most likely due to a combination of loss of mature forest habitat, residential development and the latent effects of commercial trapping. Biological characteristics of individual species, in combination with the effect of human activities, appear to have combined to affect the current distributions of carnivores in the Sierra Nevada. Periodic resampling of the distributions of carnivores in California, via remote detection methods, is an efficient means for monitoring the status of their populations. [source] Spatial and temporal variation of fire regimes in a mixed conifer forest landscape, Southern Cascades, California, USAJOURNAL OF BIOGEOGRAPHY, Issue 8 2001R. Matthew Beaty Aim In this study, we evaluated the fire-forest mosaic of a mixed conifer forest landscape by testing the hypothesis that pre-fire suppression fire regime parameters vary with species composition (tree species), and environment (i.e. slope aspect, slope position, elevation). Location Our study was conducted in the 1587 ha Cub Creek Research Natural Area (CCRNA), Lassen National Forest, CA, USA. Methods We quantified the return interval, seasonal occurrence, size, rotation period, and severity of fires using dendroecology. Results Slope aspect, potential soil moisture, forest composition, and fire regime parameters in our study area co-vary. Median composite and point fire return intervals (FRI) were longest on higher, cooler, more mesic, north-facing (NF) slopes covered with white fir (Abies concolor), Douglas fir (Pseudotsuga menziesii),white fir, and red fir (A. magnifica),white fir forests, shortest on the dry, south-facing (SF) slopes covered with ponderosa pine (Pinus ponderosa),white fir forests and intermediate on west-facing slopes dominated by white fir,sugar pine (P. lambertiana),incense cedar (Libocedrus decurrens) forests. The spatial pattern for length of fire rotation (FR) was the same as that for FRI. Fires in CCRNA mixed conifer forests occurred mainly (90%) in the dormant season. Size of burns in CCRNA mixed conifer forests were generally small (mean=106 ha), however, during certain drought years widespread fires burned across fuel breaks and spread throughout the watershed. Fire severity was mainly high on upper slopes, low on lower slopes and moderate and low severity on middle slopes. Patterns of fire severity also varied with slope aspect. Fire frequency decreased dramatically in CCRNA after 1905. Conclusions In CCRNA, fire regime parameters [e.g. FRI, fire extent, FR, fire severity] varied widely with species composition, slope aspect and slope position. There was also temporal variation in fire extent with the most widespread fires occurring during drought years. The important contributions of topography and climate to variation in the fire regime indicates that exogenous factors play a key role in shaping the fire-forest structure mosaic and that the fire-forest structure mosaic is more variable, less predictable and less stable than previously thought. Finally, some characteristics of the fire regime (i.e. fire severity, season of burn) in CCRNA are different than those described for other mixed conifer forests and this suggests that there are geographical differences in mixed conifer fire regimes along the Pacific slope. [source] Pollen-based biomes for Beringia 18,000, 6000 and 0 14C yr bp,JOURNAL OF BIOGEOGRAPHY, Issue 3 2000M. E. Edwards Abstract The objective biomization method developed by Prentice et al. (1996) for Europe was extended using modern pollen samples from Beringia and then applied to fossil pollen data to reconstruct palaeovegetation patterns at 6000 and 18,000 14C yr bp. The predicted modern distribution of tundra, taiga and cool conifer forests in Alaska and north-western Canada generally corresponds well to actual vegetation patterns, although sites in regions characterized today by a mosaic of forest and tundra vegetation tend to be preferentially assigned to tundra. Siberian larch forests are delimited less well, probably due to the extreme under-representation of Larix in pollen spectra. The biome distribution across Beringia at 6000 14C yr bp was broadly similar to today, with little change in the northern forest limit, except for a possible northward advance in the Mackenzie delta region. The western forest limit in Alaska was probably east of its modern position. At 18,000 14C yr bp the whole of Beringia was covered by tundra. However, the importance of the various plant functional types varied from site to site, supporting the idea that the vegetation cover was a mosaic of different tundra types. [source] Californian mixed-conifer forests under unmanaged fire regimes in the Sierra San Pedro Mártir, Baja California, MexicoJOURNAL OF BIOGEOGRAPHY, Issue 1 2000R. A. Minnich Abstract Aim,This study appraises historical fire regimes for Californian mixed-conifer forests of the Sierra San Pedro Mártir (SSPM). The SSPM represents the last remaining mixed-conifer forest along the Pacific coast still subject to uncontrolled, periodic ground fire. Location,The SSPM is a north,south trending fault bound range, centred on 31°N latitude, 100 km SE of Ensenada, Baja California. Methods,We surveyed forests for composition, population structure, and historical dynamics both spatially and temporally over the past 65 years using repeat aerial photographs and ground sampling. Fire perimeter history was reconstructed based on time-series aerial photographs dating from 1942 to 1991 and interpretable back to 1925. A total of 256 1-ha sites randomly selected from aerial photographs were examined along a chronosequence for density and cover of canopy trees, density of snags and downed logs, and cover of non-conifer trees and shrubs. Twenty-four stands were sampled on-the-ground by a point-centred quarter method which yielded data on tree density, basal area, frequency, importance value, and shrub and herb cover. Results,Forests experience moderately intense understory fires that range in size to 6400 ha, as well as numerous smaller, low intensity burns with low cumulative spatial extent. SSPM forests average 25,45% cover and 65,145 trees per ha. Sapling densities were two to three times that of overstory trees. Size-age distributions of trees , 4 cm dbh indicate multi-age stands with steady-state dynamics. Stands are similar to Californian mixed conifer forests prior to the imposition of fire suppression policy. Livestock grazing does not appear to be suppressing conifer regeneration. Main conclusions,Our spatially-based reconstruction shows the open forest structure in SSPM to be a product of infrequent, intense surface fires with fire rotation periods of 52 years, rather than frequent, low intensity fires at intervals of 4,20 years proposed from California fire-scar dendrochronology (FSD) studies. Ground fires in SSPM were intense enough to kill pole-size trees and a significant number of overstory trees. We attribute long fire intervals to the gradual build-up of subcontinuous shrub cover, conifer recruitment and litter accumulation. Differences from photo interpretation and FSD estimates are due to assumptions made with respect to site-based (point) sampling of fire, and nonfractal fire intensities along fire size frequency distributions. Fire return intervals determined by FSD give undue importance to local burns which collectively use up little fuel, cover little area, and have little demographic impact on forests. [source] Fire disturbance and forest structure in old-growth mixed conifer forests in the northern Sierra Nevada, CaliforniaJOURNAL OF VEGETATION SCIENCE, Issue 6 2007R. Matthew Beaty Abstract Question: This study evaluates how fire regimes influence stand structure and dynamics in old-growth mixed conifer forests across a range of environmental settings. Location: A 2000-ha area of mixed conifer forest on the west shore of Lake Tahoe in the northern Sierra Nevada, California. Methods: We quantified the age, size, and spatial structure of trees in 12 mixed conifer stands distributed across major topographic gradients. Fire history was reconstructed in each stand using fire scar dendrochronology. The influence of fire on stand structure was assessed by comparing the fire history with the age, size, and spatial structure of trees in a stand. Results: There was significant variation in species composition among stands, but not in the size, age and spatial patterning of trees. Stands had multiple size and age classes with clusters of similar aged trees occurring at scales of 113 - 254 m2. The frequency and severity of fires was also similar, and stands burned with low to moderate severity in the dormant season on average every 9,17 years. Most fires were not synchronized among stands except in very dry years. No fires have burned since ca. 1880. Conclusions: Fire and forest structure interact to perpetuate similar stand characteristics across a range of environmental settings. Fire occurrence is controlled primarily by spatial variation in fuel mosaics (e.g. patterns of abundance, fuel moisture, forest structure), but regional drought synchronizes fire in some years. Fire exclusion over the last 120 years has caused compositional and structural shifts in these mixed conifer forests. [source] Effects of temporal and spatial variations in food supply on the space and habitat use of red squirrels (Sciurus vulgaris L.)JOURNAL OF ZOOLOGY, Issue 2 2000Peter W. W. Lurz Abstract In non-native conifer plantations characterized by strong spatial and temporal variations in the availability of tree seeds in Spadeadam Forest, northern England, the home range and habitat use of red squirrels Sciurus vulgaris was very flexible. Males tended to have much larger home ranges than females and core-areas of most breeding females seemed mutually exclusive. Adult female red squirrels were found to increase their home range and core-area size in forest patches where food was less abundant. Home-range size was significantly related to home-range quality and the extent of overlap by other females. In contrast with high-quality continuous conifer forests: (1) a considerable proportion of adult males and females at Spadeadam shifted home range, (2) both sexes had much larger home ranges than reported from other habitats in Britain or Belgium. Many ranges were multinuclear, particularly from January onwards, when supplies of seeds become depleted through consumption and seed shed. Squirrels tracked the availability of conifer seeds (lodgepole pine cones throughout the study, Norway spruce cones in spring 1992 and Sitka spruce cones in autumn 1993) and intensively used several non-adjacent activity centres in temporally food-rich patches. Consequently, habitat preference changed markedly with time. The squirrels seemed to maximize nitrogen intake and to avoid the smaller seeds when possible. This resulted in an overall preference for a mixed diet of lodgepole pine and spruce seeds and avoidance of Sitka spruce seeds when Norway spruce seeds were available. These results lend support to the hypothesis of Ostfeld (1985) that when food is sparse and patchily distributed, females should develop intrasexual territoriality, concentrating their activity in food-rich patches, while males should be non-territorial and adapt their space use to the distribution of females. [source] Modeling above-ground litterfall in eastern Mediterranean conifer forests using fractional tree cover, and remotely sensed and ground dataAPPLIED VEGETATION SCIENCE, Issue 4 2010Sibel Taskinsu-Meydan Abstract Question: How can we model above-ground litterfall in Mediterranean conifer forests using remotely sensed and ground data, and geographic information systems (GIS)? Location: Eastern Mediterranean conifer forest of Turkey. Methods: Above-ground litterfall from Mediterranean forest stands of Pinus nigra, Cedrus libani, Pinus brutia and Juniperus excelsa and mixed Abies cilicica, C. libani and P. nigra was modeled as a function of fractional tree cover using a regression tree algorithm, based on IKONOS and Landsat TM/ETM+data. Landsat TM/ETM+images for the study area were used to map actual stand patterns, based on a land-cover map of species stands using a supervised classification. Results: Total amount of annual above-ground litterfall for the entire study area (12 260 km2) was estimated at 417.2 Mg ha,1 for P. brutia, 291.1 Mg ha,1 for the mixed stand, 115.5 Mg ha,1 for P. nigra, 54.6 Mg ha,1 for J. excelsa and 45.9 Mg ha,1 for C. libani. The maps generated indicate the distribution of the seasonal amount of total above-ground litterfall for different species and the distribution of species stands in the study area. There was an increase in the amount of above-ground litterfall for P. brutia stand in summer, for J. excelsa in autumn and for C. libani, P. nigra and the mixed stand of A. cilicica, P. nigra and C. libani in winter. Conclusion: Application of this model helps to improve the accuracy of estimated litterfall input to soil organic carbon pools in the Mediterranean conifer forests. [source] Coarse woody debris in Australian forest ecosystems: A reviewAUSTRAL ECOLOGY, Issue 8 2005GEMMA WOLDENDORP Abstract Coarse woody debris (CWD) is the standing and fallen dead wood in a forest and serves an important role in ecosystem functioning. There have been several studies that include estimates of CWD in Australian forests but little synthesis of these results. This paper presents findings from a literature review of CWD and fine litter quantities. Estimates of forest-floor CWD, snags and litter from the literature are presented for woodland, rainforest, open forest and tall open forest, pine plantation and native hardwood plantation. Mean mass of forest floor CWD in Australian native forests ranged from 19 t ha,1 in woodland to 134 t ha,1 in tall open forest. These values were generally within the range of those observed for similar ecosystems in other parts of the world. Quantities in tall open forests were found to be considerably higher than those observed for hardwood forests in North America, and more similar to the amounts reported for coniferous forests with large sized trees on the west coast of the USA and Canada. Mean proportion of total above-ground biomass as forest floor CWD was approximately 18% in open forests, 16% in tall open forests, 13% in rainforests, and 4% in eucalypt plantations. CWD can be high in exotic pine plantations when there are considerable quantities of residue from previous native forest stands. Mean snag biomass in Australian forests was generally lower than the US mean for snags in conifer forests and higher than hardwood forest. These results are of value for studies of carbon and nutrient stocks and dynamics, habitat values and fire hazards. [source] Review of the El Soplao Amber Outcrop, Early Cretaceous of Cantabria, SpainACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2010María NAJARRO Abstract: El Soplao outcrop, an Early Cretaceous amber deposit recently discovered in northern Spain (Cantabria), has been shown to be the largest site of amber with arthropod inclusions that has been found in Spain so far. Relevant data provided herein for biogeochemistry of the amber, palynology, taphonomy and arthropod bioinclusions complement those previously published. This set of data suggests at least two botanical sources for the amber of El Soplao deposit. The ñrst (type A amber) strongly supports a source related to Cheirolepidiaceae, and the second (type B amber) shows non-specific conifer biomarkers. Comparison of molecular composition of type A amber with Frenelopsis leaves (Cheirolepidiaceae) strongly suggests a biochemical affinity and a common botanical origin. A preliminary palynologlcal study indicates a regional high taxonomical diversity, mainly of pteridophyte spores and gymnosperm pollen grains. According to the preliminary palynologlcal data, the region was inhabited by conifer forests adapted to a dry season under a subtropical climate. The abundant charcoalified wood associated with the amber in the same beds is evidence of paleofires that most likely promoted both the resin production and an intensive erosion of the litter, and subsequent great accumulation of amber plus plant cuticles. In addition, for the first time in the fossil record, charcoalified plant fibers as bioinclusions in amber are reported. Other relevant taphonomic data are the exceptional presence of serpulids and bryozoans on the surfaces of some amber pieces indicating both a long exposure on marine or brackish-water and a mixed assemblage of amber. Lastly, new findings of insect bioinclusions, some of them uncommon in the fossil record or showing remarkable adaptations, are reported. In conclusion, a documented scenario for the origin of the El Soplao amber outcrop is provided. [source] | ||||||||||||||||