Post-agricultural Forests Research Articles

Peculiarities of tree root system development in post-agricultural forest communities

The article studies the mass of fine (up to 2 mm in diameter) roots of woody species and the patterns of their distribution across the soil profile in post-agricultural forest communities in the middle taiga of Karelia, Russia. Forest site characteristics were determined in sampling plots established following conventional procedures. The root mass was determined by the soil monolith method. Analysis showed that young communities developed a greater mass of fine roots compared to older stands. The total root occupation of the top mineral layer of soil was higher than in the forest floor. In most cases, both coniferous and deciduous roots prevailed in mineral soil layer. The relationship between fine root mass and basal area was identified.

Using the Forest Maturity Index to model understory regeneration of post-agricultural forest in the NE Carpathians

The regeneration dynamics of understory vegetation in recent forests, arising from extensive agricultural land abandonment, is closely related to soil properties and proximity to ancient forests. However, the role of topography in shaping this regeneration process, especially in mountainous regions, remains unclear.This study addresses this gap by investigating the regeneration rate of understory vegetation in mountainous recent forests within the NE Carpathians, a region profoundly shaped by large-scale population displacements in the 1940s, leading to widespread agricultural land abandonment and the subsequent development of new forests.We quantified the understory regeneration rate of recent forests through extensive phytosociological relevé surveys conducted in one vegetation season. Data were collected from 194 randomly selected plots of recent forests and 100 plots of ancient forests, each exhibiting diverse topographic characteristics. By calculating the Forest Maturity Index based on ancient forest species and employing a parametrized multiple regression model, we identified key factors influencing the understory regeneration process. We further used the obtained regression formula to model the forest regeneration rate across the entire study area (40,975 ha).Proximity to ancient forests positively influenced understory regeneration. Elevation and slope also emerged as significant determinants, with the understory regeneration rate decreasing with elevation and increasing with slope steepness. Furthermore, a higher cover of pine in the tree stand had a suppressive effect. The above-mentioned dependencies resulted in substantial variations in the modeled understory regeneration of post-agricultural forests.The utilization of the Forest Maturity Index offers invaluable insights into identifying and subsequently safeguarding well-regenerated forests. Given the prevalence of forest secondary succession in various regions, this index emerges as a key indicator for future assessments and management strategies.

Peculiarities in the Development of the Tree Root System in Post-Agricultural Forest Communities

Peculiarities in the Development of the Tree Root System in Post-Agricultural Forest Communities

Rapid Assessment of Land Use Legacy Effect on Forest Soils: A Case Study on Microarthropods Used as Indicators in Mediterranean Post-Agricultural Forests

Agriculture is known to strongly influence soil functioning. Nevertheless, its long-term effects remain not well documented in the Mediterranean region, which has a long history of human land use. The “Parc Naturel Régional du Luberon” is a good illustration of these land use changes, as its territory is now covered with forests of differing ages and histories. This study investigates the effect of past land use (agricultural terraces) on microarthropods of current forest soils. In this way, Acari and Collembola of soils from ancient forests, recent forests (developed before 1958), and very recent forests (developed after 1958) were analysed. Different pedoclimatic conditions (Meso-Mediterranean vs. Supra-Mediterranean) and two contrasted seasons (winter and summer) were taken into account in mesofauna responses. A negative effect of past agricultural land use was observed on soil microarthropod abundance in very recent forests only, whatever the pedoclimatic conditions. After at least 60 years of reforestation, this negative effect was no longer observed, indicating a recovery of these communities. Land use legacy effect on oribatid mites in post-agricultural forests depended on the pedoclimatic conditions considered, suggesting that the recovery of microarthropod communities takes more time under more arid conditions. Microarthropods can be considered as good bioindicators of past land use effects depending on pedoclimatic conditions in forest soils.

Mycoheterotrophic plants as indicators of post-agricultural forest regeneration: abundance of Hypopitys monotropa and Monotropa uniflora in post-agricultural forests changes through time

Herbaceous layers in second-growth forests are shaped by past land use. Disturbances such as agriculture may impact populations of mycoheterotrophs, non-photosynthetic mycorrhizal plants that obtain carbon from fungal networks by altering mycorrhizal communities or removing trees they derive carbon from. I tested the hypotheses that two mycoheterotrophic forest herbs increase in abundance during succession and become most common in older forests as plant communities reassemble through time. Distributions of Hypopitys monotropa and Monotropa uniflora were sampled in Athens County, Ohio, USA. I surveyed populations in a 40-site post-agricultural forest chronosequence with five upland and five valley sites in each of four age classes: 40–60, 61–80, 81–100, and >130 years since canopy closure. Aspect and elevation were measured to assess environmental influence. Both H. monotropa and M. uniflora were most common in older stands with EM tree-rich canopy composition and west- or south-facing aspects, indicating influence of historical, biotic, and edaphic factors. Hypopitys was exclusive to forests >80 years old, while M. uniflora was present in younger stands. Abundance of both species was also significantly predicted by Fagaceae basal area. Because EM trees were also most abundant in south- and west-facing uplands, environmental influence appears to be mediated through canopy composition.

Regional impacts of agricultural land use history on forest vegetation and soils: Comparing primary and post-agricultural forests in Northern New Jersey

We studied the effects of agricultural land use history on present-day forest conditions at large spatial and temporal scales. We used historic forest maps from the late 1800s to document the spatial extent of primary and post-agricultural forest cover in the 8080 km2 area of northern New Jersey outside the coastal plain, measuring the structure and composition of their vegetation and soils in 72 paired plots, and comparing the responses to agricultural land use history across regional and landscape-level environmental gradients. We estimated a 25% net increase in forest cover from the late 1800’s to 2015, with a 26% decline in primary forests during the same time. As little as 5–14% of the land area of some ecoregions are occupied by primary forests today. Post-agricultural forests comprise >46% of total forest cover and up to 72–77% in some ecoregions. Forest vegetation and soils differed significantly in the two forest types, with 8–11x greater invasive shrub and liana cover in post-ag forests, 2–5x more invasive species than native species, and reduced tree regeneration in seedling and sapling size classes (37–63%). Post-ag forest soils had a higher pH and associated base mineral concentrations (Ca, Mg), lower nutrients (NH4, %N), electrical conductivity and organic content (%C, % organic matter), and changes to soil texture (lower % sand, higher % silt and clay). Variation in these changes across large spatial and temporal scales showed few to no relationships with bedrock/surface geology, glacial history, soils, topography, forest age class or integrity metrics, indicating the robustness of these changes across a wide range of environmental contexts and conditions. Comparisons to past primary forest conditions in the same region (1948–1973) showed even greater deficits in tree regeneration and increases in invasive abundance in post-ag forests than present-day comparisons suggested. The results indicate the significance of agricultural history as a major driver of long-term and large-scale forest change. Greater protection of primary forests is needed along with prioritizing the respective needs of these different forest land use history types for stewardship and restoration in the future.

Impact of patch age and size on forest soil characteristics in European agricultural landscapes

Many landscapes worldwide are characterized by the presence of a mosaic of forest patches with contrasting age and size embedded in a matrix of agricultural land. However, our understanding of the effects of these key forest patch features on the soil nutrient status (in terms of nitrogen, carbon, and phosphorus) and soil pH is still limited due to a lack of large-scale data. To address this research gap, we analyzed 830 soil samples from nearly 200 forest patches varying in age (recent versus ancient forests) and size (small versus larger patches) along a 2500-km latitudinal gradient across Europe. We also considered environmental covariates at multiple scales to increase the generality of our research, including variation in macroclimate, nitrogen deposition rates, forest cover in a buffer zone, basal area and soil type. Multiple linear mixed-effects models were performed to test the combined effects of patch features and environmental covariates on soil nutrients and pH. Recent patches had higher total soil phosphorus concentrations and stocks in the mineral soil layer, along with a lower nitrogen to phosphorus ratio within that layer. Small patches generally had a higher mineral soil pH. Mineral soil nitrogen stocks were lower in forest patches with older age and larger size, as a result of a significant interactive effect. Additionally, environmental covariates had significant effects on soil nutrients, including carbon, nitrogen, phosphorus, and their stoichiometry, depending on the specific covariates. In some cases, the effect of patch age on mineral soil phosphorus stocks was greater than that of environmental covariates. Our findings underpin the important roles of forest patch age and size for the forest soil nutrient status. Long-term studies assessing edge effects and soil development in post-agricultural forests are needed, especially in a context of changing land use and climate.

Land use legacy footprint in Mediterranean forest soils: An infrared spectroscopy approach

Chemical properties of forest soils can strongly influence this compartment vulnerability to climate change effects. Past human activities can play a major role in structuring soil chemical properties. In the Mediterranean region, abandonment of terrace agriculture since 1860 induced the coexistence of forests with different ages. Here, soil chemical signature (SCS) was compared between very recent, recent and ancient forests using Fourier Transform InfraRed (FTIR) spectroscopy and other chemical properties (total C and N, CaCO3 percentages). Land Use Legacy (LUL) effects were analysed depending on soil depths and on contrasted climate conditions (humid vs subhumid Mediterranean climates). Statistic treatments, Linear Mixed-Effect and Anova COMmon DIMension models, were used to highlight the influence of depth’s soil, climate and LUL effects. Interestingly, the soil depth did not influence LUL effect on soil spectra. The effect of climate, LUL and their interactions were observed on the SCS. Higher available N was observed in soils from ancient forests than in soils from very recent forests. Moreover, mineral fraction discriminated soils with different LUL (very recent vs recent and ancient forests) and this depended on climate. Under subhumid climate, soils from very recent forests were indeed negatively correlated with the mineral fraction, while under humid climate, they were positively correlated to it. Finally, a recovery of soils chemical properties was observed in recent forests under humid climate, while under subhumid climate, SCS of post agricultural forests was different from that of ancient forests.

Soil Environment and Fauna Communities in Europe after Afforestation of Post-Agricultural Lands—A Review

Afforestation can make an important contribution mitigating the effects of changing climate and provide structural and functional benefits. Afforestation also provides challenges for forest managers connected with past land-use history; therefore, there is an urgent need to summarize knowledge about such habitats and point out the gaps in knowledge for planning future studies. Although post-agricultural forests cover a large forest area in Europe, our understanding of the mechanisms governing the below-ground environment is still poor, especially when soil fauna is considered. In this study, we revised knowledge about the soil environment and the response of soil fauna to afforestation on former agricultural lands located in Europe based on research articles from the ISI Web of Science database. Data came from various but distinct locations, compared forests with different types of agricultural lands, and presented previous knowledge about soil chemistry and accompanying soil fauna communities. Finally, we selected 15 studies, investigating soil fauna communities on post-agricultural lands. The meta-analysis was based on response ratio (R) for available data, although in many cases the data were incomplete. Results indicated that post-agricultural forests differ from arable lands in reference to soil pH, but not for soil organic matter and carbon content. Different soil animal groups were represented by a similar number of studies: microfauna (seven studies) and mesofauna (nine), whereas macrofauna were represented by five studies. Meta-analysis revealed that the response of soil fauna to afforestation differed between soil fauna size classes. Additionally, in total, 18 tree species, 12 soil types, and 20 soil parameters were provided in the literature but only a few of them were presented in a single study. Future studies should include the impact of microclimate, detailed stand characteristics and soil conditions, which could help to clearly describe the impact of certain tree species growing on certain soil types. In future soil fauna ecological studies, the data should include mean values, standard deviation (SD) and/or standard effort of means (SE) for abundance, species richness, diversity indices and number of collected samples. Providing the above mentioned information will give the broad audience the opportunity to include data in future comparative analyses.

Host Quality, Mediated by Land-Use History and Landscape Position, Shapes Distributions of Parasitic Plants in Postagricultural Forests

Host Quality, Mediated by Land-Use History and Landscape Position, Shapes Distributions of Parasitic Plants in Postagricultural Forests

Mapping Mature Post-Agricultural Forests in the Polish Eastern Carpathians with Archival Remote Sensing Data

Post-WWII displacements in the Polish Carpathians resulted in widespread land abandonment. Most of the pre-war agricultural areas are now covered with secondary forests, which will soon reach the felling age. Mapping their exact cover is crucial to investigate succession–regeneration processes and to determine their role in the landscape, before making management decisions. Our goal was to map post-agricultural forests in the Polish Eastern Carpathians using archival remote sensing data, and to assess their connectivity with pre-displacement forests. We used German Flown Aerial Photography from 1944 to map agricultural lands and forests from before displacements, and Corona satellite images to map agricultural lands which converted into the forest as a result of this event. We classified archival images using Object-Based Image Analysis (OBIA) and compared the output with the current forest cover derived from Sentinel-2. Our results showed that mature (60–70 years old) post-agricultural forests comprise 27.6% of the total forest area, while younger post-agricultural forests comprise 9%. We also demonstrated that the secondary forests fill forest gaps more often than form isolated patches: 77.5% of patches are connected with the old-woods (forests that most likely have never been cleared for agriculture). Orthorectification and OBIA classification of German Flown Aerial Photographs and Corona satellite images made it possible to accurately determine the spatial extent of post-agricultural forest. This, in turn, paves the way for the implementation of site-specific forest management practices to support the regeneration of secondary forests and their biodiversity.

Can Disruption of an Ant–Plant Mutualism Explain a Lack of Recovery of Forest Herbs in Post-Agricultural Forests of New York?

A substantial proportion New York's forests regenerated following agricultural abandonment around the turn of the 20th century. Many myrmecochorous (ant-dispersed) plant species are lacking in these forests decades after land abandonment despite being present in residual stands. To determine if disruption to this ant–plant mutualism can partially explain the current distribution patterns of myrmecochorous plants, we quantified the proportion of seeds removed by ants while accounting for predation by rodents in residual and post-agricultural forests. We experimentally manipulated ant access and controlled for rodent access to seeds of 3 myrmecochorous understory herbs in 3 paired residual and post-agricultural forests in central New York. We identified Aphaenogaster rudis as the primary seed disperser. We found no difference in mean (± 1 SE) proportion of seeds removed by ants between residual stands (73.7% ± 7.7%) and post-agricultural stands (75.8% ± 7.9%). Rodents removed few to no seeds (5.3% ± 1.5%), but an invasive slug, Arion subfuscus (Dusky Arion), was observed removing elaiosomes from seeds in both stand types. Our data indicated neither a lack of ant-dispersal activity nor excessive rodent predation would be limiting to dispersal of myrmecochorous seeds in post-agricultural forests during the period of our study. Given the presence of A. rudis in post-agricultural stands, programs to assist plant migration will likely be sufficient to reestablish this ant–plant mutualism in degraded sites.

Light, temperature and understorey cover predominantly affect early life stages of tree seedlings in a multifactorial mesocosm experiment

Increasing light availability by opening up the forest canopy is a key tool for forest managers to stimulate natural regeneration of trees. Tree seedlings are also impacted by a complex set of global change drivers and understorey vegetation. Here, we investigated if (altered) environmental resources and conditions due to global change, and understorey vegetation modulate tree seedling responses, i.e. emergence, survival, growth and biomass allocation, to enhanced light availability.Seeds and seedlings of three species (Quercus robur, Fagus sylvatica and Acer pseudoplatanus) were planted in a multifactorial experiment. Understorey communities were grown in 384 mesocosms on soils from ancient and post-agricultural forest, forested before 1850 and after 1950, respectively. The mesocosms were exposed to two-level full-factorial treatments of light addition, warming and nitrogen enrichment. We measured understorey vegetation cover and height, scored tree seedling emergence and seed predation, measured seedling survival during two growing seasons and measured growth after two growing seasons.We found that emergence and early survival formed critical bottlenecks for seedling establishment. Seed predation formed a barrier to emergence, while cover of understorey vegetation reduced seedling survival. The life stages of the three species were varyingly affected by the different treatments, but predominantly by light addition and warming in a positive way. We found few significant interactions between light and the other treatments, presenting limited evidence of the other drivers modulating seedling responses to increased light availability.With our experiment, we were able to further disentangle the confounding effects of light availability and warming on seedling performance. Our results confirm that managers likely facilitate tree regeneration when opening the canopy by increasing both light availability and temperature, even by slight amounts, at the forest floor. However, managers need to be aware of unintended consequences of their actions as too great an increase in understorey vegetation cover may be detrimental to seedling establishment.

Light and warming drive forest understorey community development in different environments.

Plant community composition and functional traits respond to chronic drivers such as climate change and nitrogen (N) deposition. In contrast, pulse disturbances from ecosystem management can additionally change resources and conditions. Community responses to combined environmental changes may further depend on land-use legacies. Disentangling the relative importance of these global change drivers is necessary to improve predictions of future plant communities. We performed a multifactor global change experiment to disentangle drivers of herbaceous plant community trajectories in a temperate deciduous forest. Communities of five species, assembled from a pool of 15 forest herb species with varying ecological strategies, were grown in 384 mesocosms on soils from ancient forest (forested at least since 1850) and postagricultural forest (forested since 1950) collected across Europe. Mesocosms were exposed to two-level full-factorial treatments of warming, light addition (representing changing forest management) and N enrichment. We measured plant height, specific leaf area (SLA) and species cover over the course of three growing seasons. Increasing light availability followed by warming reordered the species towards a taller herb community, with limited effects of N enrichment or the forest land-use history. Two-way interactions between treatments and incorporating intraspecific trait variation (ITV) did not yield additional inference on community height change. Contrastingly, community SLA differed when considering ITV along with species reordering, which highlights ITV's importance for understanding leaf morphology responses to nutrient enrichment in dark conditions. Contrary to our expectations, we found limited evidence of land-use legacies affecting community responses to environmental changes, perhaps because dispersal limitation was removed in the experimental design. These findings can improve predictions of community functional trait responses to global changes by acknowledging ITV, and subtle changes in light availability. Adaptive forest management to impending global change could benefit the restoration and conservation of understorey plant communities by reducing the light availability.

Patterns and drivers of forest landscape change in the Apennines range, Italy

Human activities and natural processes over millennia have shaped the forest landscapes of European mountain ranges. In the Apennines, the second largest range in Italy, the post–World War II abandonment of traditional activities has led to forest expansion. Previous analyses of land use change related to forest landscape were performed for relatively small localities and used different sampling protocols. Consequently, a replicate landscape approach and a systematic sampling design were crucial for quantifying changes at the regional scale. We investigated land cover change and landscape configurational shifts comparing different slope exposures and altitudinal zones and discussed the main drivers affecting post-agricultural forest dynamics. We selected two paired study landscapes (North-East vs South-West) of 16 km2 for each of 10 sites located along the entire range. We applied object-based classification to aerial photography from 1954 and 2012, resulting in 40 land cover maps. We assessed (i) overall landscape changes by computing land cover transitions, (ii) landscape patterns through key metrics, and (iii) reforestation dynamics through multivariate statistics and binomial generalized linear models (GLMs). Apennine landscape mosaics experienced structural simplification at lower elevation due to tree establishment in abandoned pastures, but a diffuse fragmentation of historical grasslands at higher elevation due to development of woody vegetation patches beyond the forest-grassland ecotone. Forest expansion occurred more rapidly at lower elevations, on steeper slopes, and closer to existing forests and cultivated areas. A replicate landscape approach proved useful for quantifying changes to forest cover and landscape structure along complex gradients of topography and land use history, following a diffuse agro-pastoral abandonment.

Context-Dependency of Agricultural Legacies in Temperate Forest Soils

Anthropogenic activities have affected forests for centuries, leading to persistent legacies. Observations of agricultural legacies on forest soil properties have been site specific and contrasting. Sites and regions vary along gradients in intrinsic soil characteristics, phosphorus (P) management and nitrogen (N) deposition which could affect the magnitude of soil property responses to past cultivation. A single investigation along these gradients could reconcile contradictions and elucidate context-dependency in agricultural legacies. We analysed soil from 24 paired post-agricultural (established after approx. 1950) and ancient (in existence before 1850) forests in eight European regions. Post-agricultural forest soil had higher pH, higher P-concentration and lower carbon (C) to N ratio compared to ancient forest. Importantly, gradients of soil characteristics, regional P surplus and N deposition affected the magnitude of these legacies. First, we found that three soil groups, characterising inherent soil fertility, determined extractable base cations, pH and concentrations of total N, organic C and total P. Second, regions with greater current P surplus from agriculture correlated with the highest P legacy in post-agricultural forests. Finally, we found that N deposition lowered pH across forests and increased total N and organic C concentrations in post-agricultural forest. These results suggest that (1) legacies from cultivation consistently determine soil properties in post-agricultural forest and (2) these legacies depend on regional and environmental context, including soil characteristics, regional P surplus and N deposition. Identifying gradients that influence the magnitude of agricultural legacies is key to informing how, where and why forest ecosystems respond to contemporary environmental change.

Ecological Factors Affecting White Pine, Red Oak, Bitternut Hickory and Black Walnut Underplanting Success in a Northern Temperate Post-Agricultural Forest

This study took place in southern Québec (Canada) where young stands of white ash and grey birch have been underplanted with white pine, red oak, bitternut hickory and black walnut. The establishment success of white pine and red oak was measured with and without tree shelters (to protect from deer). Ecological factors affecting the height growth of the four species were also measured for protected trees. After 6 years, the survival and total height of unprotected oak was 29% and 44.3 cm vs. 80.5% and 138.5 cm for protected oak. White pine was less affected by browsing (survival of 79.5 and 93.5%; height of 138.5 and 217.9 cm for unprotected vs. protected pine). Height of white pine was higher in the grey birch stands, while height of all hardwoods was higher in the white ash stands, which had better soil drainage, higher fertility, and an understory dominated by Rubus species. Total height of all hardwoods was significantly (p < 0.05) correlated with Rubus cover and with soil fertility. Pine and walnut height were strongly correlated (p < 0.001) to shelterwood structure (canopy openness or total basal area). Pine was less sensitive to variations in shelterwood characteristics, while black walnut showed high sensitivity. This study provides evidence that underplanting is suitable for black walnut assisted migration northward and for bitternut hickory restoration, despite soil conditions that were less favorable than in bottomland habitats mainly supporting these species in eastern Canada. Tree shelters offering protection from deer browsing and species-specific site selection are recommended for underplanting in the southern Québec region.

Land use legacies on forest understory vegetation and soils in the Mediterranean region: Should we use historical maps or in situ land use remnants?

How to move forward if we cannot understand our present from our past? The same applies for the study of ecosystems. Evidence of ecological legacies in temperate post-agricultural forests has been provided on soil physico-chemical properties and understory vegetation richness and composition, which led to distinguish ancient and recent forests. However, no land use legacies dating back more than 50 years have been reported in Mediterranean forests. The definition of ancient and recent forests usually relies on a threshold date, most often provided by historical maps. In France, the Etat-Major map is the most precise, with a relatively high resolution and drawn over the whole country with a standardised method. However, the use of historical maps only for studying land use legacies in forest is questionable in a Mediterranean context characterised by a traditional agro-sylvo-pastoral system. Using a historical ecology approach, our purpose was to examine the legacies of various former land uses on soil and understory vegetation in Mediterranean forests and to compare the relevance of two historical sources: 1860 land use map (map-based PLU) and remnants recorded in the field (in situ PLU remnants). In the Regional Natural Park of Luberon (French Mediterranean area), we inventoried plant communities and analysed soil physico-chemical properties on 100 plots with various past land uses according the Etat-Major map (arable, pasture or forest) and in situ PLU remnants (terrace, stone removal or no remnants). Compared to ancient forest, former arable land hosted more species and had deeper and nutrient-richer soils while former pasture had shallower and nutrient-poorer soils. Similarly, and compared with no remnants, terraces hosted more species and had deeper and nutrient-richer soils whereas stone removal had shallower and nutrient-poorer soils. Understory species composition significantly varied according to map-based PLU and in situ PLU remnants. However, in situ PLU remnants were globally a much better indicator of land use legacies on soil and understory plant composition compared to map-based PLU. We thus confirmed the legacies of past land use on Mediterranean forest soil and understory vegetation. We also stressed that historical ecology should rely on both field evidence and historical maps, particularly in Mediterranean landscapes with a complex history of land uses.

Lack of herbaceous layer community recovery in postagricultural forests across three physiographic regions of New York

Agricultural land-use legacies remain persistent determinants of plant-community composition, despite extended periods of recovery in postagricultural forests of New York. We surveyed the composition of vascular plant species for 33 paired residual (unconverted) and secondary (postagricultural) forest sites across three physiographic regions in New York to assess the recovery of residual forest species in secondary successional stands. There were 169 vascular plant species recorded among the 33 study sites. The residual stands exhibited slightly greater mean (± SE) species richness (26.8 ± 1.7 species per site) than secondary-interior (21.4 ± 1.2, P = 0.001) and secondary-edge (24.1 ± 1.6, P = 0.02) zones. Plant communities differed across the three physiographic regions (P = 0.001) and by stand history within regions (P = 0.004). Of the vascular plant species occurring at our sites, 22 (13%) were indicators of residual forest stands and 27 (16%) were indicators of secondary, postagricultural forest stands. Within 10 to 25 m of the historic field-forest ecotones, the relative frequencies of many residual woodland indicator species fell to 0–20% of the maxima they attained in the residual stands. Ant-dispersed (myrmecochorous) taxa represented 23% of residual and 0% of secondary forest indicators and exhibited lower migration rates (P < 0.001) than plants possessing other diaspore dispersal modes (anemochory, zoochory, barochory). In addition to plant dispersal mode, we found pH and forest-floor depth to be important determinants of plant species. Our results indicate that impoverishment of plant communities in postagricultural forests represent a regionally pervasive phenomenon with important resource management implications in the eastern USA. Residual woodlands remain important source populations for recovery of herbaceous species in postagricultural landscapes. However, given the slow historic recovery rates that we and others have observed in postagricultural secondary forests, in addition to other contemporary factors potentially inhibiting dispersal and establishment (e.g., herbivory, pollinator disruptions, invasive species), it seems likely that active restoration efforts are needed to promote full recovery of diverse, native temperate-forest herb communities.

Антропогенная трансформация постаграрных лесов юго-восточной части Свердловской области

Антропогенная трансформация постаграрных лесов юго-восточной части Свердловской области