Streamside Forests Research Articles

Characterizing riparian vegetation and classifying riparian extent using airborne laser scanning data

Riparian areas are an integral component of the forest hydrologic system. However, systematic management and conservation of riparian vegetation remains a challenge when the extent and nature of riparian vegetation is not easily characterized. Thus, describing riparian vegetation structural attributes and mapping riparian extent is important for stream protection and restoration. This study discriminated riparian and upland vegetation zones in two watersheds on Vancouver Island, Canada, and characterized vegetation attributes ascribed to streamside forest vegetation using fine-scale airborne laser scanning (ALS) data with field-based measurements for controls. Comparison of ALS metrics for riparian and upland vegetation plots indicated metrics of canopy cover, height, and vertical canopy complexity were significantly different. Machine learning was used to model the probability of riparian and upland vegetation zone extent in each watershed and to determine which ALS metrics were the most important for discriminating between these two zones. Separate models were built for each watershed and results indicated that each watershed's model had different ALS metrics that were important for model development, reflecting the different management histories associated with each watershed. Models achieved overall classification accuracies of 65–77% using a 10-fold cross validation. Probability maps were then developed to characterize riparian extent, indicating that the majority of riparian areas in these watersheds were within 20 m of a stream. Additionally, riparian areas were found up to 200 m away from the stream, which is beyond the current provincial regulation widths set for riparian buffers in forested areas in British Columbia, Canada. However, the majority (roughly 75%) of vegetation within existing management buffers was riparian, although this differed by stream classification. We conclude that ALS data provides a potentially useful source of information for determining the characteristics and extent of riparian vegetation.

Diversity of soil mites (Acari: Mesostigmata) in streamside mountain forests

AbstractHabitat loss and fragmentation are among the most influential factors responsible for recent biodiversity decline. The key to understanding the changes in ecosystem functioning is the analysis of the relationship between species diversity and environmental gradients such as those found near streamside forests. We used soil mites (Mesostigmata) as model species as they are predators in soil ecosystems, they occur in high relative abundance, their communities are species‐rich and are robust toward sampling and extraction methods. The main goals of this study were to (1) check how the plant community and associated environmental variables (light conditions, litter accumulation, and soil acidity) along mountain streams affect soil Mesostigmata abundance and diversity, and (2) to analyze the distance from mountain streams to which the ecosystem functions (Mesostigmata diversity) are affected, based on a distance gradient. We systematically established 31 study plots (500 m2) every 200 m along the watercourses, representing three habitat types along the stand composition gradient (ash‐sycamore [Fraxinus excelsior–Acer pseudoplatanus], European beech [Fagus sylvatica], and Norway spruce [Picea abies] forests) for measurements of soil litter thickness, soil acidity, and light conditions. We extracted soil Mesostigmata mites from samples in Tullgren funnels and identified them to the species level. We found that Mesostigmata abundance in forests decreased in the following order: Norway spruce forest > European beech forest > ash‐sycamore forest. Additionally, changes in Shannon diversity were associated with light conditions. In conclusion, streamside mountain forests maintained abundant, diverse and species‐rich Mesostigmata communities, which were associated with a plant community‐light condition gradient. Additionally, more abundant mite communities occurred in forests with higher soil pH values, and under higher light conditions.

On the edge: habitat restoration priorities for three critically endangered bird species on Sangihe, Indonesia

Remnant forests on the small Wallacean island of Sangihe north of Sulawesi hold the entire ranges of more critically endangered (CR) bird species than any other comparable area on earth. We develop habitat association models for three of these CR species to identify critical habitat features as well as areas where habitat falls slightly short of suitability, and to determine whether another area of forest away from the largest block might be suitable as an insurance site for a translocated population. Hopes for all three species appear almost totally pinned to forest within a 13 km2 area of the Sahendaruman crater, with virtually no near‐suitable habitat away from this site. There is, however, little overlap in habitats between one CR species and the other two: cerulean flycatcher Eutrichomyias rowleyi is associated with mature streamside forest with full canopy cover, lianas, and mid‐level growth, while Sangihe whistler Coracornis sanghirensis and Sangihe golden bulbul Hypsipetes platenae are restricted to ridgetop forest with full canopy cover and large trees. We pinpoint small areas (around 5 km2) of forest in the crater that are already suitable or can be made so with habitat management, and these are absolute priorities for conservation action. We show how habitat characteristics identified within models might be enhanced, and how features, especially certain tree species, can be used as indicators of future habitat improvement.

Effect of riparian soil moisture on bacterial, fungal and plant communities and microbial decomposition rates in boreal stream-side forests

Riparian habitats of boreal forests are considered as hotspots for biochemical processes and biodiversity, and varying width riparian buffers have been proposed to protect species diversity of the riparian forests. However, evidence of the role of soil moisture variation in shaping riparian biodiversity and ecosystem functioning remain scarce particularly regarding belowground diversity. We studied how distance from the stream and soil moisture of the riparian zone affected species richness and community composition of plants, bacteria, and fungi as well as microbial decomposition rates. Using a split-plot design with a plant survey and amplicon sequencing for microorganisms we identified taxa associated with different categories of moisture and distance from the stream along six headwater stream-sides in middle boreal forests in Northern Finland. Tea-bag Index was used to assess the decomposition rates. PERMANOVA and linear mixed-effect models were used to analyze the data. Variation in riparian soil moisture influenced species composition and richness of plants and bacteria. Plant communities also changed from herbaceous dominated to shrub dominated with increasing distance from the stream. Fungal communities, however, did not respond to soil moisture or distance from the stream, and there were only slight differences in fungal trophic guilds among moisture and distance categories. Decomposition of organic material by microorganisms was faster adjacent to the stream than further away, and moist riparian areas had higher decomposition rates than drier ones. Decomposition rates were positively related to pH, Ca, Mg and NH4 and soil temperature.Synthesis and applications We show that above- and belowground diversity and microbial decomposition are associated to soil moisture at riparian sites supporting the idea of leaving wider unmanaged buffers in moist habitats to safeguard the overall forest diversity. Our findings further emphasize the need to consider soil moisture when planning the measures for riparian protection as changes in riparian soil moisture could lead to deterioration of organic matter decomposition. Different responses of the examined plant and microbial communities to riparian soil conditions clearly imply that overall riparian diversity cannot be explained based on a single community type, and that different organisms may respond differently to human-induced changes in stream riparian zone.

Effect of Riparian Soil Moisture on Bacterial, Fungal and Plant Communities and Microbial Decomposition Rates in Boreal Stream-Side Forests

Effect of Riparian Soil Moisture on Bacterial, Fungal and Plant Communities and Microbial Decomposition Rates in Boreal Stream-Side Forests

Resource selection and movement of the coastal tailed frog in response to forest harvesting

The coastal tailed frog (Ascaphus truei) has a biphasic life-history that includes the use of montane streams adjacent to mature old growth forests. This species is at risk from a variety of land-use activities, including forest harvesting, that results in younger and more fragmented terrestrial habitats. Post-metamorphic tailed frogs are cryptic and difficult to capture, making for few studies of the terrestrial life stage of the species. At the northern extent of the species’ range, we investigated the spatial ecology of tailed frogs across riparian and adjacent upland forest in three forest types: mature to old unharvested, streamside forest retention, and clearcut. Post-metamorphic frogs were fitted with Very High Frequency radio transmitters and monitored for an average of 10.75 days (SE 0.89). Females moved further from their origin of capture during the monitoring period (x¯= 68.89 m, SE 16.3) when compared to males (x¯= 36.85 m, SE 7.9). We used Resource Selection Functions to quantify habitat selection of female and male tailed frogs. Monitored frogs were positively associated with habitats containing well-decayed coarse woody debris (≥ 7.5 cm diameter), less ambient light, adjacency to the larval stream, hygric and subhygric microsites, and cool temperatures (11–12 °C). Females were more selective in their choice of habitat than males. Overall, the relationship between distribution and activity of tailed frogs was reflective of the sex of the frog in combination with microsite or broader climatic conditions ameliorated by stand-level habitat conditions. Our data suggest that habitat management for post-metamorphic tailed frogs focus on the retention of both streamside (within 40 m) and upland forest (> 50 m from larval stream), as well as stand-level attributes such as hygric and subhygric microsites, and coarse woody debris with advanced decay.

The effect of buffer strip width and selective logging on streamside polypore communities

Preserving streamside forest habitats or buffer strips is considered to reduce forestry-related biodiversity loss in commercial forest landscapes. However, it is still unclear what type of management in and near streamside forests can be undertaken without compromising their biodiversity and natural change through succession. Using a before–after, control–impact study design, we tested the impacts of forested buffer strips (15 or 30 m wide, with or without selective logging), preserved after clear-cutting, on the changes of polypore communities in streamside boreal forests in Finland. Manipulations in 28 sites produced four treatment classes, the community compositions of which were compared with seven unmanaged controls before and 12 years after the manipulations. The polypore community composition in 15 m wide buffer strips changed differently than that in controls and resembled the community composition typically found in production forests. Moreover, selective logging tended to homogenize polypore communities. These responses of polypore communities indicate that the natural biodiversity and succession of streamside forests was disturbed in both 15 m wide and selectively logged buffer strips. Streamside forests in nonlogged 30 m wide buffer strips seemed to retain the natural polypore community composition and succession, at least during the 12-year period.

Windthrow in streamside key habitats: Effects of buffer strip width and selective logging

Streamside forests are preserved from clear-cut logging in production forests and protected with uncut buffer strips in many countries. However, buffer strips often remain narrow due to economic reasons and, therefore, provide weak protection against adverse edge effects of clear-cuts and are vulnerable to windthrow. Selective logging of buffer strips is sometimes allowed to reduce their costs, but the decreased tree density may expose the buffer to higher occurrence of windthrow. We used a replicated two-factor experiment to assess the effects of buffer width (15 m or 30 m) and selective logging (0% or 30% of the basal area removed) on the risk of windthrow in boreal streamside forests in Finland. We examined the windthrown trees 12 years after experimental logging at 29 sites and at seven unlogged control sites. In addition, we studied the influence of topography and the extent of clear-cut logging in the surrounding forests on windthrow risk. The proportion of windthrown spruces at sites with 15 m buffer strips was, on the average, six times higher than at control sites and 2.5 times higher than at sites with 30 m buffer strips. In contrast, the proportion of windthrown spruces did not differ between sites with 30 m buffer strips and control sites. Selective logging did not increase the risk of windthrow strongly. However, sites with selectively logged 30 m buffers were slightly more prone to windthrow than control sites. The proportion of windthrown trees tended to increase with the extent of the adjacent clear-cut areas on both sides of the stream. We conclude that a 15 m buffer strip is not wide enough to protect streamside forests from substantial windthrow, while a 30 m buffer strip is sufficient in most cases. Selective logging of 30 m buffers may be undertaken at sites that are not under a high risk of windthrow. If selective logging enables a wider buffer strip, it may be a better option for protecting the streamside habitat from substantial windthrow than leaving a narrow buffer strip. Moreover, clear-cut harvesting on both sides of the stream should be avoided if the aim is to prevent excessive windthrow.

Changes in streamside riparian forest canopy and leaf litter nutrient flux to soils during an emerald ash borer infestation in an agricultural landscape

The invasive forest insect pest, emerald ash borer (EAB), is causing rapid, widespread ash tree mortality across eastern North America. Riparian (streamside) forests in agricultural landscapes often represent residual patches of high quality forest habitat that, owing to their strong land/water ecological linkages, can be critical for maintaining stream water quality and aquatic and terrestrial biodiversity. When riparian forests contain high numbers of ash trees, EAB can pose a risk of disrupting some of those land/water linkages thereby reducing riparian and aquatic habitat quality. We tracked ash tree mortality, streamside forest canopy cover, leaf litter deposition rates, and nutrient flux to soils in 18 riparian forest plots with an average of 24% ash by stem density over a 5 year period from early to late stages of an EAB invasion (2010–2015). Ash tree mortality increased from an average of 10–98% over 5 years in most plots, but when blue ash were dominant, final ash mortality was about 34%. Despite the nearly complete mortality of ash trees in almost all plots by 2015, the average canopy openness measured at 1.5 m above ground only increased to about 9%, which was significantly higher than the 2010 average of 6% open. Final canopy openness was significantly but weakly (r2 = 0.24) associated with the proportion of ash in riparian plots, indicating highly patchy openness resulting from ash mortality. Ash leaf litter deposition to streamside traps declined by 84% and elm declined by 20%, whereas leaf deposition from the other four most common contributors to riparian leaf litter increased by up to 37% over the same period. The large reductions in ash litter deposition were sufficient to reduce macro-nutrient flux to the streamside forest floor and therefore likely to streams. Amounts of N, C, P, K, and Ca delivered to the streamside soils via leaf litter fall were all consistently, some of them significantly, lower by 2014 than in the baseline year of 2010. Although total leaf litter mass returned to near pre-infestation levels by 2014, the altered composition of leaf litter caused a persistent reduction in nutrient flux to riparian soils. We also measured stem density of regenerating ash saplings ( 0.5 m height) at the end of the study period and found them to be abundant with an average of 2084 stems/ha. Our results provide an empirical demonstration of EAB-induced disruptions to ecological linkages and processes in riparian forests, at least over the short term.

Squeezed from All Sides: Urbanization, Invasive Species, and Climate Change Threaten Riparian Forest Buffers

Streamside forests of urbanizing coastal regions lie at the nexus of global changes: rising sea levels, increasing storm surge, expanding urban development, and invasive species. To understand how these combined stressors affect forest conditions, we identified forest patches adjacent to urban land, analyzed adjacent land cover, modeled forest inundation, and sampled 100 sites across the Chesapeake Bay and Delaware Bay watersheds. We found that the majority of forest patches are adjacent to urban land and projected flooding will affect 8–19% of regional forested land. We observed non-native invasive plants in 94% of forest plots. Trees were predominantly native, but over half of shrub stems were invasive species and more than 80% of plots contained invasive woody vines. Disturbance of human origin was correlated with abundance of invasive trees. Signs of deer activity were common. Richness and number of growth forms of invasive plants were related to adjacent agricultural land cover. These data reveal that streamside forests are impacted by the interacting stressors of urbanization, climate change, and invasive species spread. Our results emphasize the importance of protection and restoration of forests in urban regions and point to the need for a social-ecological systems approach to improve their condition.

Long-term effects of riparian forest harvest on light in Pacific Northwest (USA) streams

AbstractRiparian forests exert strong influence on abiotic and biotic processes in adjacent streams by regulating light. Harvesting of riparian forests was once common practice, and consequently, many streamside forests across North America are in varying stages of development as they regenerate, thereby affecting stream light regimes. We used 2 approaches to evaluate the influence of riparian forest harvest and stand recovery on light availability in small mountain streams. We estimated light and canopy cover every 25 m along 11.5 km of a 4th-order stream network dominated by late-successional riparian forests that included 7 streamside harvest units 50 to 60 y old. Estimates of stream light fluxes were lower in harvest units than in up- and downstream sections bordered by old-growth forests even though only 1 stream bank was harvested in 5 of 7 units. Differences in stream light between harvested reaches and adjacent old-growth sections were greater when both banks had been logged. We also conducted a s...

Animal water balance drives top-down effects in a riparian forest-implications for terrestrial trophic cascades.

Despite the clear importance of water balance to the evolution of terrestrial life, much remains unknown about the effects of animal water balance on food webs. Based on recent research suggesting animal water imbalance can increase trophic interaction strengths in cages, we hypothesized that water availability could drive top-down effects in open environments, influencing the occurrence of trophic cascades. We manipulated large spider abundance and water availability in 20 × 20 m open-air plots in a streamside forest in Arizona, USA, and measured changes in cricket and small spider abundance and leaf damage. As expected, large spiders reduced both cricket abundance and herbivory under ambient, dry conditions, but not where free water was added. When water was added (free or within moist leaves), cricket abundance was unaffected by large spiders, but spiders still altered herbivory, suggesting behavioural effects. Moreover, we found threshold-type increases in herbivory at moderately low soil moisture (between 5.5% and 7% by volume), suggesting the possibility that water balance may commonly influence top-down effects. Overall, our results point towards animal water balance as an important driver of direct and indirect species interactions and food web dynamics in terrestrial ecosystems.

Far North Queensland

Landowners (100 males and 21 females) within the catchment of the Great Barrier Reef Lagoon located between the Barron and the South Johnstone Rivers responded to a postal survey assessing attitudes towards their streamside forests. 121 useable questionnaires were used to identify the underlying components within landowner's attitudes. Factor analysis revealed two components, namely, awareness of human impact on local streamside forest, and appreciation of environmental benefits and functions of streamside forest. Only factor 2, appreciation of environment benefits and functions of streamside forest, was found to significantly predict good streamside forest management practices as self-reported by landowners. There is a need to understand the human impact on streamside zones.

Feeding and parasitism of adultStenoperlaspp. (Plecoptera: Eustheniidae) in New Zealand

AbstractThe adult diets of two species of stonefly,Stenoperla prasina(Newman, 1845) andStenoperla maclellaniZwick, 1979 were investigated by gut content analysis. Adults were collected throughout New Zealand by light‐trapping at 77 streamside sites most of which were located in native forest.S. prasinawas widely distributed and collected at 43 sites, whereasS. maclellaniwas sampled at 10 sites in the South Island only. Of 200 S. prasinaand 42 S. maclellanidissected, 36% and 69% respectively, contained food. Microscopic examination of a subset of individuals indicated that the gut contents of both species were dominated by sooty mould fungi with lesser contributions made by plant tissue, pollen grains and the spores of tree ferns. These findings suggest that stoneflies had been feeding on the trunks, branches and foliage of trees and perhaps on fronds of tree ferns. As the abdomens of most females were packed with eggs, which mature in late‐instar nymphs it is likely that feeding provides adults with a source of immediately available energy for mating and flight. Encysted larval stages of hairworms (Nematomorpha) and a trematode were also found in both stonefly species. Metacercarial cysts of the trematode are the first records of larval flukes parasitising New Zealand stoneflies. They were found in about 43% of dissected adults of each species with up to 40 cysts present in some individuals. It is possible that the parasite's definitive host is one of New Zealand's native bats (Chiroptera), which are known to eatStenoperlaand inhabit streamside forests at some of the localities where parasitised stoneflies were taken. Overall, our results provide further evidence for the importance of sooty mould fungi as a food source for New Zealand insects and highlight the role ofStenoperlaas a vector of larval parasites from aquatic to terrestrial hosts.

ARCHAEOLOGICAL AND NATURAL SCIENTIFIC STUDIES OF PIT-GRAVE CULTURE BARROWS IN THE VOLGA-URAL INTERFLUVE

Introduction The Pit-Grave culture spread on huge territory of Eastern Europe steppe from Kazakhstan and south Ural to the Dniestr region. The eastern Pit-Grave artefacts were found in the Volga-Ural interfluve and in the south Ural region on the territory of the Astrakhan, Volgograd, Saratov, Samara, and Orenburg oblasts, Russia. The environmental conditions of the steppe existed on the most part of the territory and forest steppe--in the north (Fig. 1). Today, natural conditions are determined by the continental climate, which corresponds to hot summers with low precipitation and severe winters with a lot of snow. The flora of watersheds is typical for the Volga sheep fescue-feather grass steppe (the type of steppe where sheep fescue and feather grass flourish). Various kinds of meadow grass, bushes, and streamside forests grow in river valleys and gulches. The paleoclimatic conditions of the Pit-Grave culture are different to the modem climate. Eneolithic and Pit-Grave culture existed in the favourable natural conditions practically all the time. The precipitation was 50 mm higher compared to the humidity today. The environmental conditions and temperature drops were milder than we had in past decades (Spiridonova & Aleshinskaya 1999; Khokhlova et al. 2006; 2010; Khokhlova 2012). Many scientists think that the climate change and the emergence of aridity period coincided with the start of the Late (Poltavka) stage of the Pit-Grave culture and the Catacomb culture spread to the west of Volga (Demkin et al. 2006; Shishlina 2007; Khokhlova et al. 2010; Khokhlova 2012). [FIGURE 1 OMITTED] V. V. Golmsten, P. S. Rykov, I. V. Sinitsyn, K. F. Smirnov, N. Ya. Merpert, V. P. Shilov, N. K. Kachalova, I. B. Vasilyev and other archaeologists studied the Pit-Grave sites in the Volga-Ural interfluve in the 20th century. During the Smirnov expedition the first Pit-Grave culture barrows (kurgans) were discovered at the end of the 1950s and beginning of the 1960s. Smirnov (1965) compared the Ural materials with the Lower Volga graves and found that there are skeletons in right lateral crouched position. After considering unique metal finds (a knife and a hammer) archaeologists came to the conclusion that during the Pit-Grave period an independent metallurgy center appeared on the base of the Kargala copper deposit (80-90 km to the north of Orenburg) in the south Ural region (Chernykh 1966, 68 f.). Later, at the end of the 20th century, the research by E. N. Chernykh proved the above-mentioned statement. This added the original character of the Ural group of the Pit-Grave culture and historical area (Chernykh 2002, 7 ff). At the beginning of the 1970s N. Ya. Merpert published the monograph, in which he summarized all the data concerning the Pit-Grave culture (Merpert 1974). The scholar singled out three local groups of sites within the Volga-Ural Pit-Grave cultural and historical area: the Ural, the Lower Volga, and the Middle Volga. Since 1977 the Pit-Grave research has been carried out under the guidance of N. L. Morgunova in the Orenburg oblast. She discovered diverse Pit-Grave complexes. In the second part of the 1980s the Pit-Grave culture research became well targeted and systematic. It resulted in considerable growth in the number of analysed Pit-Grave barrows (Morgunova & Kravtsov 1994). The first periodization of the Ural Pit-Grave culture was put forward. Scholars raised some questions concerning the economy and the structure of the Early Bronze Age society (Morgunova 1991). We formed the hypothesis of singling out the Middle Volga-Ural local type of the Pit-Grave culture (Turetskij 1999). Results of various kurgan studies in the area together with a lot of finds--various metal artefacts substantially changed the popular opinion that the Ural Pit-Grave culture had peripheral character. However, by the end of the 20th century it had become quite clear that the Pit-Grave sites were essential for applying new methods so that archaeologists could exploit new sources to find solutions for different complicated problems first of all the issues concerning the origin, the periodization and the chronology of the culture. …

Slow recovery of bryophyte assemblages in middle-aged boreal forests regrown after clear-cutting

Clear-cutting followed by even-aged forestry is transforming forests around the globe. There is growing concern that considerable parts of the native forest biodiversity will not be able to re-colonize these new stands before the next clear-cutting. The development of species assemblages during the full forestry rotation period must be understood in order to assess the need for management adaptations and to get a basis for their design. Knowledge is accumulating from studies of permanent plots before and shortly after clear-cutting, but for later stages only comparative studies have been published (space-for-time substitutions). In this study, I combined this comparative approach with direct monitoring of the pace of assemblage recovery in boreal stands regrown after clear-cutting half a century ago (treatment stands). I found little re-colonization in assemblages of mosses and liverworts between an initial survey to a resurvey 15years later in 0.1-ha permanent plots of upland and stream-side forest. The assemblages of the treatment stands were still significantly different from those in matched old control forests that had never been clear-cut. The treatment stands had significantly fewer species of liverworts and of the substrate-based species subgroup “wood or bark”, and the six most negatively affected species were liverworts more or less specialized to this substrate. The only significant recovery recorded over the 15years was for the “rocks or boulders” subgroup in upland stands, probably related to a shadier and moister climate resulting from canopy development. During the inter-survey period, some of the upland treatment stands were thinned. All disfavored subgroups recovered less in thinned than in not thinned upland stands, most likely as a result of a return to lighter and drier microclimates and direct mechanical disturbance. The incomplete and slow recovery halfway into the forestry rotation period calls for action. Adaptation of thinning for conservation has rarely been implemented in boreal forest management, but has a large potential. To facilitate re-colonization by disfavored liverworts and mosses growing on wood or bark and/or under shaded and moist conditions, I suggest retention of unlogged patches during thinning and addition of coarse deadwood on the ground in these patches. Such measures would also favor re-colonization of other late-successional species.

Landscape-scale factors driving plant species composition in mountain streamside and spring riparian forests

Effective sustainable management of riparian forests requires an understanding of both the local physical setting and larger system at the landscape scale. Although site-specific influences on riparian forests are well studied, landscape-scale factors driving species composition are insufficiently recognized, especially regarding forests in spring-fed areas. In this study we ask three questions: (1) What are the main topographic factors driving the species composition in mountain riparian forests at the landscape scale? (2) What are the differences in environmental controls between riparian forests growing along river banks and in spring-fed areas? (3) Are species responses to environmental gradients in streamside and spring-fed environments consistent with plant traits or life history strategies? To address these questions, we used a dataset of vegetation plots sampled along 100 rivers in the Sudetes (southwestern Poland, Central Europe) and GIS-derived topographic variables, including the elevation, slope, topographic wetness index (TWI), stream power index (SPI), potential solar radiation and distance from river source. The significance of the variables was tested by the ordination technique (CCA). In addition, species responses (Huisman–Olff–Fresco models) were analysed for the species that fitted the ordination models best. The results showed that floristic variation in streamside forests is related to distance from the river source, altitude and SPI; while, floristic variation in spring forests is linked to altitude and solar radiation. Moreover, the frequency of particular response curve types varies between streamside and spring forests: the common presence of unimodal responses indicates that streamside forests are much more diverse in terms of community turnover than spring forests. The study highlights different landscape-scale environmental parameters that control the variation in species composition in streamside and spring forests. Streamside forests are the products of their catchments and considerably depend on the conditions that exist within the contributing area, while forests growing in spring-fed areas are mainly controlled by local conditions. We conclude, that effective management and conservation, especially approaches based on emulation of natural disturbances, should take these differences into consideration by developing site-specific management guidelines for both types of riparian forests.

Comparison of riparian and upland forest stand structure and fuel loads in beetle infested watersheds, southern Rocky Mountains

Extensive outbreaks of mountain pine beetle (MPB), spruce beetle (SB), and other insects are altering forest stand structure throughout western North America, and thereby contributing to the heterogeneity of fuel distribution. In forested watersheds, conifer-dominated riparian forests frequently occur as narrow linear features in the landscape mosaic and contribute to the spatial complexity of forest stands and fuel complexes. These streamside forests are valued for providing aquatic and terrestrial habitat, serving as sources of instream and floodplain large wood, and maintenance of streamside microclimates and stream water quality. Despite the ecological importance of riparian forests, few data exist on riparian stand attributes and fuel complexes in watersheds affected by recent beetle outbreaks. To address this need, we measured stand characteristics and fuel loads in riparian areas and adjacent uplands. Within beetle-infested watersheds in northern Colorado and southeastern Wyoming, we sampled 30 pairs of riparian and upland plots (0.05ha). Our goal was to identify bark beetle induced differences in forest structure and fuel profiles between riparian and upland stands. Specific objectives were: (1) to quantify and compare riparian and upland forest characteristics, specifically structure, extent of insect-caused canopy mortality and understory regeneration; (2) to characterize and compare riparian and upland fuel profiles. Basal area did not differ significantly for live, dead, or total (live+dead) overstory trees (⩾10cm diameter at breast height (DBH)) between upland and riparian stands, although variability was high between plot types and among plots. Although riparian and upland plots were both dominated by lodgepole pine, Engelmann spruce, and subalpine fir, they differed in relative proportions of lodgepole pine (higher in uplands) and Engelmann spruce (higher in riparian areas). For these two species, bark beetles caused greater than 80% mortality in diameter classes larger than 20cm DBH across all plots. For subalpine fir, which is not directly affected by MBP or SB, live overstory basal area and stem densities were roughly similar in riparian and upland plots. The combination of MPB-and-SB-caused canopy mortality has diminished differences in overstory basal area composition of riparian and upland stands, making them more structurally similar than prior to the beetle outbreaks. Total understory stem densities of poles, saplings and seedlings were largely comparable across plot types. However, understory live subalpine fir densities were significantly higher in both riparian and upland plots compared to lodgepole pine and Engelmann spruce, suggesting that fir will play an increasingly important role in future forest development across the landscape. With the exception of 1-h fuels and herbaceous plant cover (higher in riparian plots), fuel complexes were also similar in riparian and upland plots, with total woody fuel loads of approximately 45Mgha−1. Although current basal area, understory characteristics and surface fuel distribution are largely similar in riparian areas and uplands, fuel distribution and corresponding fire risk will likely change as the SB infestation progresses, stands respond to overstory mortality, and dead trees fall.

The preservation status of the lichen biota in the designed Special Area of Conservation NATURA 2000 „Middle Łyna River Valley – Smolajny”

The paper presents the list of 159 taxa, including 151 lichens and 8 saprotrophic or parasitic (lichenicolous) fungi, recorded in the designed Special Area of Conservation NATURA 2000 „Middle Łyna River Valley – Smolajny” (the Forest Division of Wichrowo). The analysed area (2953 ha) covers mostly forest communities, with natural character, associated with the valley of the Łyna river (hillside lime-oak-hornbeam forests, streamside alder-ash forest, riparian black alder forest).

Streamside Forest Buffer Width Needed to Protect Stream Water Quality, Habitat, and Organisms: A Literature Review

AbstractThis literature review addresses how wide a streamside forest buffer needs to be to protect water quality, habitat, and biota for small streams (≤~100 km2or ~5th order watershed) with a focus on eight functions: (1)subsurface nitrate removalvaried inversely with subsurface water flux and for sites with water flux >50 l/m/day (~40% avg base flow to Chesapeake Bay) median removal efficiency was 55% (26‐64%) for buffers <40 m wide and 89% (27‐99%) for buffers >40 m wide; (2)sediment trappingwas ~65 and ~85% for a 10‐ and 30‐m buffer, respectively, based on streamside field or experimentally loaded sites; (3)stream channel widthwas significantly wider when bordered by ~25‐m buffer (relative to no forest) with no additional widening for buffers ≥25 m; (4)channel meandering and bank erosionwere lower in forest but more studies are needed to determine the effect of buffer width; (5)temperatureremained within 2°C of levels in a fully forested watershed with a buffer ≥20 m but full protection against thermal change requires buffers ≥30 m; (6)large woody debris(LWD) has been poorly studied but we infer a buffer width equal to the height of mature streamside trees (~30 m) can provide natural input levels; (7, 8)macroinvertebrate and fish communities, and their instream habitat, remain near a natural or semi‐natural state when buffered by ≥30 m of forest. Overall, buffers ≥30 m wide are needed to protect the physical, chemical, and biological integrity of small streams.