Clear-cut Forest Research Articles

Microbial community structure in recovering forests of Mount St. Helens

IntroductionThe 1980 eruption of Mount St. Helens had devastating effects above and belowground in forested montane ecosystems, including the burial and destruction of soil microbes. Soil microbial propagules and legacies in recovering ecosystems are important for determining post-disturbance successional trajectories. Soil microorganisms regulate nutrient cycling, interact with many other organisms, and therefore may support successional pathways and complementary ecosystem functions, even in harsh conditions. Historic forest management methods, such as old-growth and clearcut regimes, and locations of small mammal enclo and clearcut forests, as well as in locations of historic short-term gopher enclosures (Thomomys talpoides), to evaluate community response to forest management practices and to examine vectors for dispersing microbial consortia to the surface of the volcanic landscape. These biotic interactions may have primed ecological succession in the volcanic landscape, specifically Bear Meadow and the Pumice Plain, by creating microsite conditions conducive to primary succession and plant establishment.Methods and resultsUsing molecular techniques, we examined bacterial, fungal, and AMF communities to determine how these variables affected microbial communities and soil properties. We found that bacterial/archaeal 16S, fungal ITS2, and AMF SSU community composition varied among forestry practices and across sites with long-term lupine plots and gopher enclosures. The findings also related to detected differences in C and N concentrations and ratios in soil from our study sites. Fungal communities from previously clearcut locations were less diverse than in gopher plots within the Pumice Plain. Yet, clearcut meadows harbored fewer ancestral AM fungal taxa than were found within the old-growth forest.DiscussionBy investigating both forestry practices and mammals in microbial dispersal, we evaluated how these interactions may have promoted revegetation and ecological succession within the Pumice Plains of Mount St. Helens. In addition to providing evidence about how dispersal vectors and forest structure influence post-eruption soil microbiomes, this project also informs research and management communities about belowground processes and microbial functional traits in facilitating succession and ecosystem function.

How loss of nature through clear-cutting forestry affects well-being.

The United Nations declares that the global degradation of ecosystems represents a danger to human health. Deterioration of forests is one of several threats against the natural systems. The aim of this exploratory study was to investigate people's experiences with clear-cutting and how it had affected their health and well-being. Qualitative data from six people who valued forest ecosystems were collected through semi-structured interviews and analyzed in accordance with Graneheim and Lundman's qualitative content analysis (Graneheim, U. H. and Lundman, B. (2004) Qualitative content analysis in nursing research: concepts, procedures and measures to achieve trustworthiness. Nurse Education Today, 24, 105-112). Clear-cutting was not regarded as an environment-friendly forestry method. The interviewees described emotional reactions such as grief and poor mental well-being when beloved forests were clear-felled. The grief was partly because of a personal loss of place and recreation area that was important for their physical and emotional well-being. Another part was grief on behalf of nature itself, that is, the loss of habitats of animals and plants and a worsening of the global climate. The interviewees held that emotions related to loss of nature were insufficiently communicated in public discourse. They felt powerless and unable to influence forestry because of what they experienced as an impenetrable industry. Clear-cutting of forests may result in poor well-being among people who value forest ecosystems. More focus on planetary health is needed, including healthy public policy promoting forest management that considers people's need for nature experiences and possible ecological grief when forests are totally and abruptly cleared.

Soil pH and Nutrient Content Sustain Variability of Soil Bacterial Community Structure and Activity after Forest Clear-Cutting

Clear-cutting is the most robust intervention in a forest ecosystem, causing marked changes in ecosystem processes. Although the effects of forest harvesting have been widely investigated, comparative studies can provide vital supplementary information concerning specific fields, including changes in soil microbiota structure and functioning. Our study examined the soil bacterial community composition, diversity, and activity of a mixed pedunculate oak stand over three years after clear-cutting based on 16S rRNA sequencing and substrate-induced respiration data. In addition, we conducted a yearly comparison with a control oak stand already in the regeneration phase. According to our results, the forest harvest caused only limited changes in the diversity, structure, and activity of the soil bacterial community of the oak stand, suggesting that soil parameters influence the soil bacterial community structure and functioning more significantly than the cessation of forest cover.

Clear-cutting of temperate forests in late successional stages triggers successional setbacks extending compositional recovery by an additional century

Clear-cutting is used by foresters worldwide to harvest timber from forest ecosystems. Clear-cutting of cool–wet boreal forests in late successional stages can maintain successional trajectories pointed toward the composition of a late successional stages. However, clear-cutting of warm–dry boreal forests in late successional stages can trigger reversion of successional trajectories back toward forests of earlier stages because early-successional shade-intolerant species are more abundant than in cool–wet boreal forests, a process that is referred to as a successional setback. Such successional setbacks can generate sustainability issues by extending the expected time to compositional recovery after clear-cutting. This can lead to an overestimation of allowable cuts of economically important late-successional species and subsequently to a temporary forest composition conversion if the occurrence of successional setbacks remains unassessed. Temperate forests in late successional stages are warmer and drier than boreal forests and consequently include more early-successional shade-intolerant species susceptible to encroach clear-cut areas. Even if current ecological knowledge suggests that temperate forests could be susceptible to post-clearcut successional setbacks, a comprehensive assessment has yet to be undertaken. The objective of the present study was to assess whether clear-cutting has triggered successional setbacks in temperate forests. Therefore, we studied post-clearcut successional trajectories by using forest inventory data covering the entire temperate forest of the province of Québec, eastern Canada (209 000 km2). Clear-cutting triggered successional setbacks in both ecological regions forming the temperate forest. After clear-cutting, successional trajectories of trees pointed toward the composition of an early successional stage. To address this sustainable management issue in a comprehensive manner with clear-cutting, foresters could use partial cut approaches.

Clear-cuts support the metapopulation of a critically endangered butterfly

Clear-cutting is believed to have a negative impact on forest biodiversity, but numerous studies have also shown its positive effects, especially in temperate and boreal regions. This phenomenon is mainly related to the creation of early successional habitats that serve as temporary meadows. Among the species that benefit the most are those associated with semi-natural grasslands, i.e. biotopes that have been disappearing from the landscape due to agricultural intensification. A good example is the Danube Clouded Yellow Colias myrmidone, one of the most endangered butterflies in Europe. Its last lowland metapopulation in the EU exists in the Knyszyn Forest (north-eastern Poland), but the species occurrence is limited to the eastern parts of this large forest complex. All currently known habitats are forest clear-cuts located mainly on former agricultural land, i.e. mostly extensively used pastures that were afforested in the 20th century. Chamaecytisus ruthenicus, the only local larval food plant of C. myrmidone, is currently found almost exclusively in first-generation forests. Logging allows the host plants to flourish, and clear-cuts are colonized by the butterfly. In 2022, intensive mark-release-recapture studies were carried out in the focal metapopulation. The estimated metapopulation size was 4643 adults, indicating a six-fold increase compared to previous studies conducted in 2017. This was plausibly mainly due to the increase in the area of potential habitats, as butterfly densities were very similar in both seasons. The improved connectivity between habitat patches resulted in a very high proportion of dispersing individuals successfully reaching other patches, which is in contrast to the dispersal mortality of ca. 50% observed five years earlier. A relatively high mobility was also observed in the case of the much smaller spring generation. To our knowledge, this is the first study to document a reversal of selection against dispersal and it demonstrates that such changes can occur relatively quickly, i.e. within a few generations. In order to ensure the long-term persistence of the viable C. myrmidone metapopulation and mitigate the negative effects of climate change, a network of stable forest-steppe-like habitats in combination with the creation of clear-cuts in forest stands with presence of C. ruthenicus would be optimal. To achieve this, we recommend leaving some selected clear-cuts without replanting to restore grasslands (through grazing and removal of excess trees, shrubs and invasive plants), while the suitability of ephemeral habitats could be improved through appropriate silvicultural measures.

Production of greenhouse gases by logging residue in boreal clear-cut forests

AbstractForest deadwood is an important carbon reserve, estimated to contain 8% of the total forest carbon. This type of woody debris is recognized as a source of carbon dioxide (CO2), as the carbon is released back into the atmosphere by microbial decomposition. Production of methane (CH4) and nitrous oxide (N2O) has also been reported. In managed forests, logging residues form a major source of fine deadwood, but its role in the greenhouse gas exchange of forest ecosystems is poorly understood. We studied the greenhouse gas production of spruce and birch left-over fine woody debris and estimated the residence time of these residues at 18 spruce-dominated boreal forest sites in Central Finland. The study areas consisted of clear-cut forest stands, totally covering approximately 47 hectares, with logging residue ages varying between 0 and 10 years. The research was carried out over eight months from May to December 2019. We observed that CO2 dominated the greenhouse gas production of the logging residues, with the production being regulated by air temperature, tree species, residue age, and wood moisture. Emission of CO2 continued throughout the research period with a clear seasonal pattern. Production of CH4 and N2O was also observed, but not in climatically-relevant amounts. Deadwood half-life was estimated at 18 years for spruce and 9 years for birch. Our study demonstrates that logging residues form a mid-term carbon reserve and suggests that global warming could reduce the lifetime of the residues as a result of elevated and temperature-dependent CO2 release in the studied Myrtillus type forest stands.

Seeing through their eyes: Revealing recreationists’ landscape preferences through viewshed analysis and machine learning

Planning for outdoor recreation requires knowledge about the needs and preferences of recreationists. While previous research has mainly relied on stated preferences, recent advances in spatial data collection and analysis have enabled the assessments of actual usage patterns. In this study, we explored how landscape characteristics interact with the attributes of recreationists to determine their area choice for recreation. Using a public participation GIS (PPGIS) approach we asked residents of a Swedish city in the boreal region to draw typical recreational routes and identify favourite places for recreation on a digital online map (1389 routes, 385 individuals). We employed a novel methodology, where LiDAR data was used to calculate what was visible along all routes and at favourite places (viewsheds) in order to more realistically capture the landscape that each recreationist had experienced. Using machine learning modelling, we compared landscape characteristics of experienced areas with areas available to each recreationist. Our novel approach yielded accurate models that revealed that water environments, recreational infrastructure and deciduous forests increased the probability of choosing an area for recreation, while urban environments, noise, forest clearcuts and young forests had the opposite effect. Characteristics of the recreationists such as age, gender, level of education, or of the activity, such as type of activity performed, did not meaningfully influence area choice. Our findings suggest that it is possible to improve the conditions for recreation by developing recreational infrastructure, maintaining recreation opportunities close to waters, and adapting forest management in areas important for recreation.

Detection and Analysis of Forest Clear-Cutting Activities Using Sentinel-2 and Random Forest Classification: A Case Study on Chungcheongnam-do, Republic of Korea

This study provides the methodology for the development of sustainable forest management activities and systematic strategies using national spatial data, satellite imagery, and a random forest machine learning classifier. This study conducts a regional province-scale approach that can be used to analyze forest clear-cutting in South Korea; we focused on the Chungcheongnam-do region. Based on spatial information from digital forestry data, Sentinel-2 satellite imagery, random forest (RF) classifier, and digital forest-type maps (DFTMs), we detected and analyzed the characteristics of clear-cut areas. We identified forest clear-cut areas (accounting for 2.48% of the total forest area). The methodology integrates various vegetation indices and the RF classifier to ensure the effective detection of clear-cut areas at the provincial level with an accuracy of 92.8%. Specific leaf area vegetation index (SLAVI) was determined as the most important factor for accurately detecting clear-cut areas. Moreover, using a DFTM, we analyzed clear-cutting characteristics in different forest types (including private, national, natural, and planted forests), along with age class and diameter-at-breast-height class. Our method can serve as a basis for forest management and monitoring by analyzing tree-cutting trends in countries with forest areas, such as Republic of Korea.

Submonthly Assessment of Temperate Forest Clear-Cuts in Mainland France

Submonthly Assessment of Temperate Forest Clear-Cuts in Mainland France

Changes in the Number of Vascular Plant Species during Reforestation of Clearcut Forests

The article aims to describe the patterns of changes in the number of vascular plant species in communities at different stages of forest regeneration after clearcutting using the space-for-time substitution method. Large-scale logging in boreal forests leads to a simplification of the territory’s forest cover (the formation of even-aged stands), which in turn leads to a decrease in the diversity of forest communities and species diversity. These tendencies have been confirmed for many groups of organisms, especially those associated with old trees and dead wood; however, this is not so clear for vascular plants. We investigated plant communities at different stages of regeneration. We used the so-called space-for-time substitution (chronosequence) method of building dynamic series for four forest ecotopes, where industrial clearcuts are most actively carried out. We showed that the fertility of forest ecotopes determines the species pool—the richer the conditions, the more species that can potentially inhabit the community. At the same time, the structure of the tree stand significantly affects the composition and number of species in the community. The lowest species richness was in old-growth forests characterized by the dominance of one species in the tree stand and one or two vascular plant species in the ground cover. With insignificant fluctuations in the average number of species between stages of forest regeneration after logging, some communities at clearcuts in bilberry (Vaccinium myrtillus L.) pine (Pinus sylvestris L.) and spruce (Picea abies (L.) H.Karst.) forests have high species diversity due to the occupation of the site by species of open habitats. These clearcuts are located not far from settlements and close to roads.

Shifting cultivation and logging change soil organic carbon functional groups in tropical lowland rainforests on Hainan Island in China

Recent evidence has demonstrated that tropical forest secondary succession has significant influences on soil organic C (SOC) storage. However, the changes in the SOC functional groups with forest restoration are still uncertain. In this study, the stock and functional groups of SOC in tropical forest recovery after two types of disturbance were measured, and the key influencing factors were analyzed. The SOC stocks were significantly higher in the young-secondary forests after shifting cultivation and in the clear cut forests than in the old-growth forests. However, the shifting cultivation and logging practices significantly increased the ratio of carbohydrate C to N-alkyl/methoxyl C (CC/MC), indicating that the decomposition degree of SOC in the old-growth forests was higher. The proportion of aromatic C in soil was higher in the young-secondary forests after shifting cultivation than in the old-growth forests. The proportion of aromatic C in litter and fine roots, the α-diversity of soil fungal and bacterial communities, and soil phosphorus were positively correlated with soil aromatic C between the shifting cultivation secondary and old-growth forests. The proportion of O-alkyl C in soil was higher in the logged forests than in the old-growth forests. The proportion of O-alkyl C in litter was positively correlated with O-alkyl C in soil between the logged and old-growth forests. Our results suggest that the labile O-alkyl C functional group recovers more rapidly after logging practices, and restoration after shifting cultivation increases the labile carbohydrate C functional group and aromaticity in tropical lowland rainforests. However, SOC has greater chemical stability in terms of the decomposition degree in tropical old-growth forests.

On the uncertainty in estimates of the carbon balance recovery time after forest clear-cutting.

An essential metric for describing carbon dynamics in managed forest landscapes is the recovery time of the carbon balance after clear-cutting. Here, we demonstrate how the age-dependent mathematical trajectory is affected by both the selected model and data availability, leading to considerable uncertainty in the modelling of the net ecosystem production (NEP) over stand age. We further show that the initial carbon loss estimates associated with the timing of the source-sink transition (SST) are significant, but may have a limited effect on the total carbon sequestration at the end of the standard (RP, 120 years) or optimal (OCS) rotation periods.

Munching Moose Cool Forest Floors

By making clear-cut forests patchier, moose create a reflective surface that bounces back sunlight and keeps temperatures down.

Formalizing a Two-Step Decision-Making Process in Land Use: Evidence from Controlling Forest Clearcutting Using Spatial Information

In this paper, we examine a particular case of land use pattern: forest management activities facing an uncertainty related to spatial information signals received. We investigate the combination of two well-known theoretical approaches, the Blackwell theorem and entropy analysis, in providing a decision support framework for decision makers. We examine the uncertainty related to the information signals received within a decision support context and compute the optimal actions. Drawing on satellite imagery as an additional source of information provided by French spatial data infrastructure (SDI), we illustrate our approach through a clear-cutting control case study. The control of clear-cutting is a central issue in forest management. In order to perform an efficient control operation, uncertainty regarding the decisions to be taken needs to be minimized. Reducing uncertainty in a decision-making context related to forest management provides greater opportunities for improving productivity and for saving time and money. The results show that the information structure through the SDI signals has the most significant information power. Moreover, a maximum of two information structures can be compared when applying the Blackwell theorem. However, while using the entropy approach, a comparison of several information structures can be performed.

Farmland birds on forest clear-cuts: Liked by some, avoided by others

Many bird species typical to farmland have declined in numbers in recent decades. Some farmland bird species occur outside farmland in other open man-made habitats, such as forest clear-cuts. Given that in Sweden the total area of clear-cuts (5–6 %) almost equals that of farmland (8 %), clear-cuts have the potential to be an important habitat for some farmland birds. We investigated how bird community composition and species abundance on Swedish clear-cuts varied with geographical region, clear-cut characteristics and the surrounding landscape, with special focus on farmland species. Based on short visits in 2017–2019, we surveyed the occurrence of birds on 300 representative clear-cuts in Sweden, including six regions and 1300 km of latitude. We counted 1170 birds of 66 different species, including 10 out of 15 bird species in existing farmland bird indicators. Both bird community composition and species abundance varied with clear-cut size, age, vegetation height, region and proportion of nearby farmland, depending on species’ ecology. All six farmland species being proportionally common on clear-cuts are, when in farmland, dependent on residual habitats such as pastures and field borders with bushes and trees. In contrast, a third of the dedicated farmland species were scarce in clear-cuts, probably avoiding them because of predator-related avoidance of forest edges and/or a lack of suitable nest sites or food resources. To determine the full importance of forest clear-cuts for farmland species, and potentially make them more favourable for farmland birds, more studies are needed on the reproductive success on clear-cuts and which site features make them suitable habitat. This study did not determine the consequences of clear-cuts for forest birds across the forest cycle, consequences which needs to be balanced against any gains for farmland birds.

Sõjakas kaitse – konfliktid loodus- ja kultuuripärandi hoiu kujundamisel / Warlike Protection – Conflicts in Shaping the Preservation of Natural and Cultural Heritage

Artiklis uurime Eesti looduse ja kultuuri kaitsel tekkinud teravaid vastasseise, mida osalejad on mõnikord nimetanud sõdadeks. Näitejuhtumid ulatuvad pühapaikade kaitselt metsa ja linnalooduse kaitseni. Vaatleme artiklis, kuidas vastasseisud on arenenud, milliseid argumente kasutatakse ning millised konflikti osapooled neis eristuvad. Meie eesmärk ei ole otsida konfliktidele lahendusi või neid ennetada – selle asemel soovime mõista, miks mõnikord muutub looduse ja kultuuri kaitse sõjakat retoorikat kasutavaks konfliktiks.
 Summary
 This paper studies examples of the protection of natural or cultural objects in Estonia developing into sharp conflicts during the past couple of decades. Various mechanisms have been developed to avoid, prevent and solve conflicts, yet sharp oppositions still occur. Our aim is not to provide yet another methodology of conflict solving, but rather to look behind it: who participates in such conflicts, what their reasons and arguments are, what kind of rhetoric they use. Such an approach proceeds from Juri Lotman’s suggestion that it is not agreements, but contradictions that make a dialogue fruitful. 
 The case studies discussed in the paper range from folkloric sacred sites to the protection of forest and natural objects in urban environments. In all examples, we could observe the presence of two parties that we call the ‘developers’ and the ‘protectors’. In all cases, the developers found themselves in the middle of a conflict they had not foreseen and could not handle, as their only purpose was to develop the initial project, be it a building, forest clearing or the like. In terms of conflict management, ‘developers’ have always been followers of the conflict, reacting to it, but not leading it. The other side, ‘protectors’, consists of an amorphous group of people, some of whom are local inhabitants, while others participate in the protection because of their world view, moral or ideological reasons. In all cases observed it is the ‘protectors’ who lead it to a conflict – mostly as they are un-institutionalised, and thus less visible, so in order to become an equal partner and force developers into a discussion, they use conflict rhetoric and methods. Conflicts are usually expanded in public and on social media in the form of short and easy-to-read messages. Mediatisation is the main characteristic of contemporary conflicts and is adopted by both sides. 
 Our cases demonstrate that a clear and uniform narrative is important in order to control a conflict and make the other side accept it. Protection of folkloristic sacred sites has been guided by Maavalla Koda, a representative body of a leading contemporary pagan organisation in Estonia. Likewise, protecting forests from clearcutting has been directed by grass-root organisations. In the case of the folkloric sacred sites, the protectors have been successful and the developments have been stopped in almost all cases. Avoiding forest clearcutting has not been so unambiguously successful, but the aggressive rhetoric and active public campaigns have certainly influenced the public opinion in Estonia. Other cases, in which there have been no organisations in the background and that have lacked a common narrative, e.g. protecting a white willow in Tallinn’s suburb of Haabersti, have not been successful. Due to the missing common narrative and lack of a leader, several persons or groups were trying to act as leaders and distribute their message, which ended with a mixture of dissimilar statements, which eventually led to the protectors losing their credibility.
 The core of such conflicts lies in a collision of different worldviews, characterised by opposing rhetoric, in which one party is using economical reasoning, while the arguments of the other are based on nature conservation, protecting of cultural and national values, and mixed with spiritual claims. Such different standpoints lead any discussion into a situation of opposition in which a compromise and solutions are difficult or even impossible to find. However, in Metsapoole the local dwellers, who acted against the State Forest Management Centre, deliberately excluded any spiritual arguments. Choosing rational rhetoric let them speak the same “language” as the Forest Management authorities and the conflict ended with a reappraisal of the plans of the State Forest Management Centre.
 There certainly are multiple reasons why conflicts arise in protecting natural and cultural objects. In addition to differences in world views, the effects of NIMBY attitudes or personal disagreements are obvious. Still, often the cases follow a similar pattern in which the conflict is brought to the public and is guided by social media and media rules. In this process, emotional arguments become more important than rational ones, which deepens the gap between the two sides involved in the conflict.

Is it possible that the structure of tropical rainforests has recovered 40 years after clear-cutting?

Abstract The tropical rainforest of Bajo Calima, Buenaventura, Colombia, was known for its large biodiversity and enormous regeneration potential. During the 1970–90s, industrial use through clear-cutting gave rise to secondary forest (SF), which is now a collective property of the communities that inhabit it. The productivity of secondary forest would recover after 30 years according to the linear recovery trend, as predicted by Mazuera (1985). The purpose of conducting this research in Bajo Calima, Colombia was to quantify the productivity of SF at different ages after clear-cutting. Plots of 0.1 ha were selected after 23, 27, 31 and 35 years of SF following clear-cutting of the initial primary forest (PF). It is now managed through selective logging. Samples of equal size of PF and SF without selective logging, called mature secondary forest MSF (> 40 years), were used as controls. The productivity variables of the SF expressed as basal area, volume (Vol) and aerial biomass (AB), on average for the four ages studied was 45%, 29% and 22% compared to the productivity of the PF, and 94%, 50% and 49% with respect to the productivity of the MSF. Without the opportunity to reach maturity the trend predicted by the recovery model was not achieved and the SF showed productive characteristics far below those of the initial primary forest.

Selective and clear-cut logging have varied imprints on tree community structure in a moist semi-deciduous forest in Ghana

Logging-induced disturbance can be an important agent of change in tropical forests. Understanding the relative impacts of specific logging regimes on tree community structure is essential for forest management and biodiversity conservation. In this study, we assessed the response of tree community structure to selective and clear-cut logging in a moist semi-deciduous forest in Ghana. We quantified the diversity, composition, density and basal area of trees (diameter at breast height ≥5 cm) in 30 20 × 20 m plots in each of three forest management systems (selectively logged, clear-cut logged, old-growth). Our results showed that the two logged forests harboured significantly lower tree species diversity than the old-growth forest. Nevertheless, the selectively logged forest supported significantly higher tree species diversity than the clear-cut logged forest. Similarly, both logging regimes caused shifts in tree species composition, but the shift was higher in the clear-cut forest than the selectively logged forest, indicating a better recovery in the selective logging stands. Selective and clear-cut logged forests supported similar stem density of trees, but they were lower than that of the old-growth forest. Finally, the old-growth forest exhibited significantly higher basal area than the selectively logged forest, which in turn, had significantly higher basal area than the clear-cut logged forest. Overall, selective logging imprints on tree community structure were lower than clear-cut logging due to faster recovery by the former. Our findings suggest that logged tropical forests may require a long period to fully recover.

Long-Term Changes in Abundance and Composition of Forest-Floor Small Mammal Communities in a Landscape with Cumulative Clearcutting

Responses of forest-floor small mammals to clearcutting are species-specific with generalists occupying a range of habitats, and specialists persisting on clearcuts for variable periods. We investigated the responses in abundance and species composition of small mammal communities to cumulative clearcutting of coniferous forests on a landscape that had four independent clearcutting events (Periods 1 to 4) over a 42-year interval from 1979 to 2020 in south-central British Columbia, Canada. We ask if the small mammal communities have changed significantly over these decades owing to removal of old-growth forest by clearcut harvesting. Hypotheses (H) predicted that the small mammal community would (H1) increase in abundance, species richness, and diversity on new clearcuts owing to the availability of early seral post-harvest habitats from cumulative clearcutting; and (H2) have higher mean abundance, species richness, and species diversity in clearcut than uncut forest sites, owing to availability of vegetative food and cover. A third hypothesis (H3) predicted that abundance of (i) early seral vegetation (herbs and shrubs) and (ii) small mammal populations, will be greater in ungrazed clearcut sites than in those grazed by cattle (Bos taurus). Mean total numbers of small mammals on new clearcuts declined in Periods 3 and 4, and hence did not support the abundance part of H1. Much of this decline was owing to low numbers of the long-tailed vole (Microtus longicaudus) and meadow vole (M. pennsylvanicus). Two generalist species: the deer mouse (Peromyscus maniculatus) and northwestern chipmunk (Neotamias amoenus), contributed to high mean species richness and diversity in Periods 2 and 3 before these metrics declined in Period 4, and hence partly supported H1. The similarity in mean total numbers of small mammals in Periods 2 to 4 did not support the abundance prediction of H2 that total numbers would be higher in clearcut than uncut forest sites. Higher mean species richness (Periods 2 and 3) and diversity (Period 3) measurements on clearcut than forest sites, particularly in the early post-harvest years, did support these parts of H2. The vegetation part (i) of H3 was not supported for herbaceous plants but it was for shrubs. The small mammal part (ii) of H3 that populations would be higher in ungrazed than grazed clearcut sites was supported for abundance but not for species richness or diversity. The decline and near disappearance of both species of Microtus was possibly related to the reduction in plant community abundance and structure from grazing (at least for shrubs) and potentially from drought effects associated with climate change. Loss of microtines from these early seral ecosystems may have profound negative effects on various ecological functions and predator communities.

Human-environmental interactions and seismic activity in a Late Bronze to Early Iron Age settlement center in the southeastern Caucasus

Long-term human-environmental interactions in naturally fragile drylands are a focus of geomorphological and geoarchaeological research. Furthermore, many dryland societies were also affected by seismic activity. The semi-arid Shiraki Plain in the tectonically active southeastern Caucasus is currently covered by steppe and largely devoid of settlements. However, numerous Late Bronze to Early Iron Age city-type settlements suggest early state formation between ca. 3.2-2.5 ka that abruptly ended after that time. A paleolake was postulated for the lowest plain, and nearby pollen records suggest forest clearcutting of the upper altitudes under a more humid climate during the Late Bronze/Early Iron Ages. Furthermore, also an impact of earthquakes on regional Early Iron Age settlements was suggested. However, regional paleoenvironmental changes and paleoseismicity were not systematically studied so far. We combined geomorphological, sedimentological, chronological and paleoecological data with hydrological modelling to reconstruct regional Holocene paleoenvironmental changes, to identify natural and human causes and to study possible seismic events during the Late Bronze/Early Iron Ages. Our results show a balanced to negative Early to Mid-Holocene water balance probably caused by forested upper slopes. Hence, no lake but a pellic Vertisol developed in the lowest plain. Following, Late Bronze/Early Iron Age forest clear-cutting caused lake formation and the deposition of lacustrine sediments derived from soil erosion. Subsequently, regional aridification caused slow lake desiccation. Remains of freshwater fishes indicate that the lake potentially offered valuable ecosystem services for regional prehistoric societies even during the desiccation period. Finally, colluvial coverage of the lake sediments during the last centuries could have been linked with hydrological extremes during the Little Ice Age. Our study demonstrates that the Holocene hydrological balance of the Shiraki Plain was and is situated near a major hydrological threshold, making the landscape very sensitive to small-scale human or natural influences with severe consequences for local societies. Furthermore, seismites in the studied sediments do not indicate an influence of earthquakes on the main and late phases of Late Bronze/Early Iron Age settlement. Altogether, our study underlines the high value of multi-disciplinary approaches to investigate human-environmental interactions and paleoseismicity in drylands on millennial to centennial time scales.