Alder Plantations Research Articles

Features of the formation of the floodplain ecosystem of the black alder cluster in the conditions of the Orenburg Urals

The article provides original information on the peculiarities of the formation of a floodplain ecosystem with the predominant tree species Black Alder, a cluster type in the conditions of the steppe (treeless) Orenburg Urals. The object of study is located in a zone of extremely insufficient and unstable moisture in the floodplain area of the Ilek River during certain periods of the year. A bioecological assessment of the black alder plantation and its phenological features of development in the conditions of the arid steppe are given. Taxation characteristics of the stand allow us to give a qualitative assessment of the black alder cluster. Currently, on the territory of the Orenburg region there is no vector for the reproduction and promotion of natural regeneration of black alder, which is primarily due to the poor knowledge of the formed spatial ecotones. The identification of cluster plantings, which ontogenetically and phylogenetically demonstrate the ability to form stable natural, dynamically developing forest ecosystems, under the influence of anthropogenic load, has important scientific and practical significance.

The Good, the Bad, and the Useable Microbes within the Common Alder (Alnus glutinosa) Microbiome-Potential Bio-Agents to Combat Alder Dieback.

Common Alder (Alnus glutinosa (L.) Gaertn.) is a tree species native to Ireland and Europe with high economic and ecological importance. The presence of Alder has many benefits including the ability to adapt to multiple climate types, as well as aiding in ecosystem restoration due to its colonization capabilities within disturbed soils. However, Alder is susceptible to infection of the root rot pathogen Phytophthora alni, amongst other pathogens associated with this tree species. P. alni has become an issue within the forestry sector as it continues to spread across Europe, infecting Alder plantations, thus affecting their growth and survival and altering ecosystem dynamics. Beneficial microbiota and biocontrol agents play a crucial role in maintaining the health and resilience of plants. Studies have shown that beneficial microbes promote plant growth as well as aid in the protection against pathogens and abiotic stress. Understanding the interactions between A. glutinosa and its microbiota, both beneficial and pathogenic, is essential for developing integrated management strategies to mitigate the impact of P. alni and maintain the health of Alder trees. This review is focused on collating the relevant literature associated with Alder, current threats to the species, what is known about its microbial composition, and Common Alder-microbe interactions that have been observed worldwide to date. It also summarizes the beneficial fungi, bacteria, and biocontrol agents, underpinning genetic mechanisms and secondary metabolites identified within the forestry sector in relation to the Alder tree species. In addition, biocontrol mechanisms and microbiome-assisted breeding as well as gaps within research that require further attention are discussed.

Effect of Different Vegetation Restoration on Recovery of Compaction-Induced Soil Degradation in Hyrcanian Mixed Forests: Influence on Soil C and N Pools and Enzyme Activities

Reforestation with native and non-native tree species is one of the most effective strategies to cope with climate change, and is also the most effective management method for solving soil erosion problems in degraded forests around the world. The current research investigates three skid trails, which were planted with three species in the clearcutting areas, in comparison with a natural forest of hornbeam (CB; Carpinus betulus L.) and velvet maple (AV; Acer velutinum Boiss.) and degraded land without trees (DL), as well as evaluates the recovery of soil characteristics in the skid trails in response to the planting of native species, including black alder (Alnus glutinosa (L.) Gaertn.), and non-native species, including eastern cottonwood (Populus deltoides L.) and Italian cypress (Cupressus sempervirens L. var. horizontalis (Mill.) Gord.) in a mid-term period of 25 years, in the Hyrcanian forests in northern Iran. Significantly higher litter nitrogen (N), phosphorus (P), and potassium (K) were detected in the plantation of black alder (AG), whereas the lowest values were measured under the DL treatment. Soil physio-chemical properties significantly differed among treatments, except silt content. Among the soil chemical properties, N storage and available nutrients of P and K under the black alder plantation were fully restored as compared to the value observed at the hornbeam and velvet maple (CB-AV) stand over a 25-year period after soil disturbance and planting. Over a 25-year period after logging operations, soil biological and microbial properties of carbon and nitrogen, and enzyme activity in the black alder plantation were partially recovered, but these values have not returned to pre-harvest level at the CB-AV treatment as control. Overall, these results suggested that black alder had greater positive effects on the recovery of soil properties than other trees due to the faster litter decomposition as a N-fixing species, and its labile substrate with low organic C and high N concentration. Therefore, black alder reforestation should be increase in future ecosystem restoration in the area influenced by logging operations.

Assessment of a 20-year-old mixed western redcedar/red alder plantation in southwestern British Columbia

A replacement series designed trial containing mixed and pure stands of western redcedar and red alder (cedar: alder; 100:0, 75:25, 50:50, 0:100) was monitored over a 20-year period. Tree and stand growth performance across the pure and mixed species treatments were inconclusive. Inherent site variation in soils and microclimate resulted in a range of survival and productivity responses. After twenty years since planting, total stand volumes were similar across the treatments, ranging between 145 and 165 m3/ha. Average cedar height and diameter growth performance surpassed alder growth performance in the last 7 years. Soil C, N and exchangeable cations (K, Ca, and Mg) trended towards greater accumulation with increasing red alder proportion. These observations indicate cedar in combination with alder may further benefit from enhanced soil fertility over the next decades as stands continue to develop.

Suitability of Fast-Growing Tree Species (Salix spp., Populus spp., Alnus spp.) for the Establishment of Economic Agroforestry Zones for Biomass Energy in the Baltic Sea Region

The main goal of this review was to provide an assessment of the potential of fast-growing tree species for the suitable transformation of agroforestry areas for biomass production in the Baltic Sea region. Our interest was to highlight the research on the management process of agroforestry zones by establishing short rotation plantations with the tree species Salix spp., Populus spp. and Alnus spp. to explore the prospects of planning these zones as biomass producers. Short rotation forestry (SRF) with trees whose rotation period is 15 to 30 years, depending on the species, is the most suitable approach for management of these agroforestry zones. Willows (Salix spp.) and poplars (Populus spp.) are suitable for short rotation coppice (SRC), as these tree species can be harvested at much shorter intervals, respectively, 1–5 and 4–10 years, facilitating their use in agricultural systems. The rotation period of Alnus spp. in short rotation plantations for energy wood production is generally assessed to be 15–30 years. The black alder plantations in agroforestry zones are used for sawnwood and firewood production, with a rotation period of 20–40 years. The calculated repayment period of the economic agroforestry zone is about 10–15 years, if 2021 costs and prices are used.

Variation in Carbon Sequestration and Soil Properties in Relation to Stand Age in Maple and Alder Plantations

ABSTRACT Increased CO2 levels caused by human activities (e.g., fossil fuel consumption and deforestation) has become a major concern for climate change and caused environmental problems. Afforestation/reforestation can help mitigate CO2 emission in the atmosphere by sequestering atmospheric carbon (C) in tree biomass. Herein, the above- and below-ground C sequestration of two pioneer tree species, including Acer velutinum Bioss and Alnus glutinosa L plantation stands of 25 (A25) and 35 (A35) years old were studied. The mean annual growth of diameter at breast height (cm/year) was significantly higher in A35 than A25, while the mean growth of height (m/year) was significantly higher in A25. The total and mean annual growth of the tree biomass and C storage (root and trunk) was significantly higher in A35. The amount of soil C sequestration in A35 was also significantly higher than in A25. The above-ground C sequestration and the annual average of C sequestration of the trees were positively correlated with soil moisture, pH, nitrogen, and phosphorus. Our study illustrates the benefits of considering stand age in the growth and developmental patterns of forest ecosystems in estimating terrestrial C stocks.

Restoration strategy drives the leaf litter myriapod richness (Arthropoda: Myriapoda) on a protected area

Objective: To determine the leaf litter myriapod community in two restoration strategies of a protective area of Colombia, a secondary forest and an Andean alder plantation. Scope: The knowledge of the biodiversity of invertebrates associated with leaf litter breakdown in restoration forests may contribute to assessing the restoration process efficiency and success. Within this forested soil biodiversity framework, myriapods influence organic matter dynamics by transforming leaf litter (or other plant-derived materials), reducing the surface of decomposition, and affecting decomposer communities and their interactions. Methodology: We designed a leaf litter translocation experiment using leaf litter of Alnus acuminata Kunth and Hedyosmum bonplandianum Kunth, the most abundant species in each restoration strategy underway from the 60s in the Reserva Natural Río Blancoy Quebrada Olivares, Manizales, Colombia. We measured the myriapod richness and abundance two and four months after beginning the leaf litter decomposition experimental trials. Main results: Classes Diplododa, Chilopoda, and Symphyla colonized the leaf litter in both restoration strategies. The restoration strategy affected myriapod richness, abundance and composition. Myriapod richness and abundance were greater in the Andean alder plantation, millipedes were the most abundance myriapods. Myriapod composition also differs among litter species. The plant composition of each restoration strategy could lead to differences in litterfall quality and, consequently, in the resources available for the colonization of the myriapod community, which contributes directly and indirectly to the decomposition process in the restoration strategies.

Bird functional diversity in restored and secondary forests of the Colombian Andes

Forest plantations may have detrimental effects on biodiversity. However, these plantations are widely used to restore degraded habitats, yet their contribution to restoring functional diversity remains largely unknown. We assessed vegetation structure, resource availability, and bird abundance, as well as bird morphological, behavioral, life history, and functional diversity in ~35‐year‐old monospecific protected Andean alder (Alnus acuminata) forest plantations in the Central Andes range at elevations between 2,400 and 2,800 m, to determine if plantation structure and resource availability favor bird functional diversity. We compared our findings to a 35‐ to 45‐year‐old secondary forest that had naturally regenerated. We found similarities in bird functional diversity but different functional composition between the Andean alder plantation and secondary forest. The bird life history, behavioral, and morphological traits from the secondary forest were more heterogeneous than those from the plantation. In addition, standing dead trees in the Andean alder plantation promoted bird functional diversity and the presence of birds in the plantation interior. Overall, vegetation structure and understory resource availability of Andean alder plantations appear sufficient to enable bird functional diversity partially resembling that of secondary forests in the region.

Conversion of Andean montane forests into plantations: Effects on soil characteristics, microorganisms, and microarthropods

AbstractTropical montane forests in the Andes are subjected to deforestation and subsequent transformation into pastures. Abandoned pastures are frequently reforested by planting monoculture timber plantations, resulting in reduced aboveground diversity and changes in soil characteristics compared to primary forests. In this study, we evaluated differences in soil properties (litter layer thickness, pH, water content, and C‐to‐N ratio) between degraded primary montane forest and monoculture pine (Pinus patula) and alder (Alnus acuminata) plantations and their effects on density, diversity, and community structure of litter and soil‐living mesofauna, with focus on oribatid mites (Acariformes). The study was performed in a montane region in the southern Ecuadorian Andes (2,000–2,600 m a.s.l.). C‐to‐N ratios in the litter and upper 5 cm soil layer were higher in pine plantations, while other soil characteristics were similar between vegetation types. Surprisingly, microbial biomass and density of soil mesofauna in the litter layer did not differ between vegetation types, while density and species richness of oribatid mites were higher in pine plantations. Community structure of oribatid mites differed between vegetation types with only a few species overlapping. The results indicate that quality and diversity of litter were not the major factors regulating the mesofauna community. Instead, soil animals benefited from increased habitat structure in thicker litter layers and potentially increased availability of root‐derived resources. Overall, the results suggest that from a soil animal perspective, monoculture plantations are less detrimental than commonly assumed and enrichment of abandoned plantations with native tree species may help to restore tropical montane forests.Abstract in Spanish is available with online material.

Large scale manipulation of the interactions between key ecosystem processes at multiple scales: why and how the falcon array of artificial catchments was built

Understanding how natural processes arise from complex interactions between particular processes at small spatiotemporal scales and in turn how these processes form patterns at large spatiotemporal scales is one of the current principal questions in environmental science.The problem is very complicated, as in many cases, key processes are often studied by researchers in separate disciplines such as ecology, soil science or hydrology. One of the major obstacles is that the processes at a landscape scale are difficult to manipulate and, in many cases, even measure. In particular, the belowground processes are in many cases overlooked or at least understudied. Here we briefly describe a methodological solution used to cope with this problem and describe artificial catchments designed for experimental manipulation at the level of a landscape, called FALCON. This array has two treatments: one mimics a site reclaimed using an alder plantation and the other was left to unassisted primary succession. For each treatment, there were two replicates in four similar catchments. Individual catchmentsare hydrologically isolated from the environment and equipped with instruments, so that all the main processes and all significant flows of substances and energy in the ecosystem can be monitored, including the cycling of water, nutrients and gas between the ecosystem and the atmosphere. In addition, in each catchment there are sets of lysimeters, which allow the study of small-scale processes and how these can be extrapolated to the catchment scale. In addition, two lysimetric fields exist alongside the catchments for monitoring the effects of the experimental manipulation.

Vertical distribution of soil fauna and microbial community under two contrasting post mining chronosequences: Sites reclaimed by alder plantation and unreclaimed regrowth

Vertical distribution of soil biota is not well understood. Here we studied the development of vertical distribution of soil chemical and biological properties in two post-mining chronosequnces in heaps after open cast coal mining, one left to succession (sites 20, 35 and 60 years old) and one reclaimed by levelling and Alder (Alnus glutinosa and Alnus incana) afforestation (sites 10, 25, 40, and 60 years old) near Sokolov, Czechia. When spoil material is compacted during levelling and afforestation, as in reclaimed sites, the effect of time in soil biota development was less important than in spontaneous succession where no compaction occurs. Soil depth was a stronger explanatory factor in explaining the soil microbial biomass variations under reclamation regimes while comparatively less strong under spontaneous succession which points at the impact of spoil compaction on vertical development of organisms. Spontaneous succession encourages a more diverse and dynamic vertical, as well as horizontal, faunal community development, especially across time. Breaking down fauna into ecological subgroups, time was more of an important factor for fauna active below ground (endogeic), than for surface-dwelling fauna likely due to further soil profile development by time. Calculated depth in which 90% individuals occur shows that considering only the depth of 0–10 cm overlooks a substantial part of some faunal groups (e.g. Pauropoda and Symphylan) that are abundant in deeper layers. Soil depth is also more of a strong predictor of soil biota than soil C content, indicating that the population decrease in soil biota community with depth cannot be explained only by decreasing organic matter content.

CUT-AWAY PEATLAND RE-CULTIVATION WITH FAST GROWING WOODY PLANTATIONS: COST-BENEFIT ANALYSIS

In Latvia peat production is historically important economic sector, giving significant contribution to rural economic development and providing work places in rural areas, where other job opportunities are limited. Every peat extraction field has certain lifespan, based on economic, social or ecological assumptions. Every peat field could be extracted for set period of time, after which peat extraction is not feasible any more. Current legislation in Latvia requires re-cultivating of places, where mineral resources, including peat, were extracted. Aim of the study is to evaluate afforestation as one of the cut-away peatland re-cultivation possibility. Economic analysis were done for extracted peat field afforestation with birch, black alder, grey alder, pine, spruce, hybrid aspen, poplar and willow. The economic calculations were done comparing different timber products from plantations, different planting materials and plantation lifespans. Lowest investment costs for plantation establishment on cut-away peatlands are for pine and spruce plantations and highest for willow plantations. Highest revenues in plantations with 20 years rotation cycle are in poplar plantations with 0.2 m cuttings and lowest in grey alder plantations. In plantations with rotation cycle 40 years highest revenues are in hybrid aspen plantations and lowest in pine plantations. 

Alnus glutinosa L. Gaertn. as potential tree for brackish and saline habitats

Over 800 million hectares of land worldwide are affected by salinity. Predicted scenarios of global climate change include a rise in sea level, which may severely affect coastal forest areas. Black alder (Alnus glutinosa) is a tree species known to tolerate heavily waterlogged soils, but its salt resistance is still unclear. The aim of our study was to assess A. glutinosa growth under soil salinity as a possible tree for wet, salt-affected sites in a changing coastal environment due to climate change. We hypothesised that: a) growth parameters are directly related to soil conditions; and b) salinity and waterlogging can limit black alder growth. For our research, we evaluated 9-11-year-old black alder plantations in Poland, one in a saline area and two reference sites on non-saline soils (one with higher moisture content). The growth of trees at each site was characterised by calculating the growth success, mean diameter at breast height, the mean height and the standard deviations from the means. We also calculated the distribution of diameters in each population, regression models for growth as the relationship between diameter and height, and coefficients of variance. The means between sites were compared by one-way ANOVA with Scheffe’s post-hoc comparisons. To characterise soil conditions we took soil samples for each site and compared their properties by the same statistical tests.Under saline conditions, black alder growth was limited in terms of height, diameter at breast height and growth success. Salinity also affected the trees’ variability, growth form and growth pattern. However, these effects were comparable to those observed in the non-saline waterlogged site. The models of growth described by regression demonstrated similar reduction of growth dynamics in these two sites. Moreover, the coefficients of variation in diameter and height of trees in these sites were similar and higher than in non-stressed site. In addition, at the saline and waterlogged sites black alder trees had relatively large number of root suckers, whereas in non-stressed site this was not the case. On the plantations in stressed environments there had been losses in the A. glutinosa stand, which had been spontaneously settled by other species of trees and shrubs, which increased species richness. Therefore, regarding climate change, in our opinion black alder can be considered as an option for planting in brackish coastal areas, where nature conservation and watershed management are at least as important as wood production.

Effect of Fertilization and Bacterial Inoculation on Nutrient Status in Coal Mine Soil under Alder (Alnus sibirica) Plantation

This study was conducted to assess the effect of fertilization and nitrogen fixing (N-fixing) bacterial inoculation on the available nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg), present in the coal mine soil, by growing N-fixing plant species, alder (Alnus sibirica). The study was conducted in a greenhouse of the Forest Science Department, Chungbuk National University, South Korea, during the period of May 2019 to July 2019. A completely randomized design (CRD) comprising of four treatments, including T0—non-fertilized non-inoculation (control), T1—fertilization, T2—bacterial inoculation and T3—fertilization along with bacterial inoculation with three replications were used in the study. The results of the study showed that available N (NH4+-N and NO3−-N) in the coal soil were increased by the applied treatments for alder, as compared to control. Apart from control, difference was also found for increasing ammonium (NH4+-N) between treatments T1 and T3 and for increasing nitrate (NO3−-N) between treatments T1 and T2 and treatments T2 and T3. Available P and K in the soil also increased when NPK fertilizer was applied solely, and together with inoculation to the plants but reduced at other treatments. Therefore, it can be concluded that fertilization and biological N fixation in alder plant can improve the fertility of coal mine soil, and hence, this plant species could be a good option for the reclamation of degraded coal mine soil.

Long-term afforestation effect and help to optimize degraded forest lands and reducing climate changes

The present study examined the forest floor, soil properties, and dynamics of greenhouse gas fluxes in 23-years old stands of alder (Alnus subcordata C. A. M.), maple (Acer velutinum Bioss.), cypress (Cupressus sempervirens L. var. horizontalis), and pine (Pinus nigra) sites in northern Iran. A degraded natural forest (DNF) with sparse trees including Parrotia persica C. A. M., Carpinus betulus L., and Diospyros lotus L. located near the afforested stands was selected as the control region. Fifteen forest floor and topsoil (0–15 cm) samples per site were taken and analyzed in the laboratory. In addition, the seasonal changes in the fluxes of CO2, CH4, and N2O were studied over a year. The quality of the forest floor differed among the sites, indicating the highest N, and the lowest C concentrations in the alder stand. The soil bulk density, pH, available nutrients (P, Ca, and Mg), earthworm activities and microbial biomass N were significantly higher in the alder stand with organic C being the least. The microbial biomass C did not differ among the studied sites, whereas the total N was significantly higher in the alder ≈ maple sites having the minimum C/N ratios. High contents of water were found in the DNF site. The highest CO2 (0.31 mg CO2 m−2 d−1) and N2O (0.42 mg N2O m−2 d−1) fluxes were observed in the DNF site. The CH4 flux showed higher amounts in the DNF ≈ cypress ≈ pine (0.12, 0.11 and 0.07 mg CH4 m−2 d−1, respectively) sites than in the maple ≈ alder (−0.05, and − 0.04 mg CH4 m−2 d−1, respectively) plantations. The highest values of all fluxes were measured in August, whereas the lowest were detected in February. This research recommends a plantation with suitable native broad-leaved species along with a forestation management plan to rehabilitate the forests of the DNF area.

Probability assessment of climate change impacts on soil organic carbon stocks in future periods: a case study in Hyrcanian forests (Northern Iran)

Simulations of soil organic carbon (SOC) stocks under climate change are partly subject to uncertainties deriving from the Global Climate Models (GCMs) used for weather projections of future climates. For this reason, SOC simulations are generally performed with a set of GCMs to avoid misleading results. SOC stocks were measured in different land covers in a forest area of Northern Iran (maple, alder, oak, cypress and a mixed natural forest), and the model RothC was used to predict SOC changes under climate change scenarios. We studied the effects on SOC stock changes deriving from an ensemble of nine GCMs and two Representative Concentration Pathways (RCPs), projected on four future periods (FPs) of 20 years between 2020 and 2099. The frequency analysis of SOC stock changes indicated a different effect of the GCMs/RCPs ensemble in the four future periods, with patterns showing more evident nonlinear probabilities of SOC changes in the 2030s and 2050s compared to the almost linear probabilities in the remaining future periods. This would imply that the effect of the GCMs/RCPs ensemble is more important in very close and intermediate future scenarios (the 2030s and 2050s) compared to fully realized climate change scenarios (the 2070s and 2090s). Results indicated the need to provide assistance in the management strategies in the reforestation sector in close and intermediate climate change scenarios. In fact, maple and quercus plantations had the highest probability of cumulated SOC change proving more sensitive to climate change. Conversely, cypress and alder plantations could limit the decrease of SOC stocks representing a good option for GHG mitigation in close and intermediate climate change scenarios and should be preferred in the afforestation of the degraded natural forest, and in mixed plantation systems within maple and oak stands.

Nutrient dynamics in an Andean forest region: a case study of exotic and native species plantations in southern Ecuador

Information about nutrient dynamics is of upmost importance in order to contribute to the restoration of degraded forest environments in the Andes of southern Ecuador. This study aims to investigate the differences of nutrient dynamics between a native alder (Alnus acuminata) and an exotic pine (Pinus patula) tree species in this region. Based on litterfall, forest floor and mineral topsoil (0–20 cm) of two pine and two alder plantations, we studied the litterfall production and its seasonality; temporal variations of nutrient concentrations, stoichiometric ratios and potential nutrient return (PNR) of leaf-litterfall; mean residence times (MRT) of nutrients in the forest floor; and assessed soil biogeochemical properties. Our results showed that total litterfall production in pine was twice as high as in alder. Litterfall biomass seasonality was similar for both species and highly associated to periods with less precipitation. Pine exhibited the highest seasonality of nutrient concentrations and stoichiometric ratios. PNR of N, K, Ca, and Mn exhibited the major differences between the species. The annual PNR of N and Ca were higher in alder, while those of K and Mn were higher in pine. Pine exhibited higher MRT values for C, N, P, S, Cu, and Zn, while alder showed the higher for Mg, K, Mn, and Ca. In soils, alder exhibited higher concentrations and stocks of nutrients, but not for C. Although, the soil microbial biomass was similar under both species, microbial activity was different. C and net N mineralization were higher in alder, and nitrification dominated over ammonification processes. In general, our findings show a faster cycling of nutrients in alder than in pine.

Tree species identity governs the soil macrofauna community composition and soil development at reclaimed post-mining sites on calcium-rich clays

We tested the effect of main soil characteristics and tree species on earthworm community composition and abundance in reclaimed spoil heaps planted with five different tree species. Earthworm and soil macroarthropod abundance and biomass were highest in alder plantations, followed by oak plantations. The numbers of soil macrofauna were positively correlated with the total soil N content, which was highest in alder plantation. The correlation was strongest for endogeic earthworms (genus Aporrectodea and Octolasion). Soil moisture, measured in top 10 cm, affected only endogeic species. Other soil variables (pH, Ca) did not have a strong effect on earthworms. The earthworm community composition was similar in alder and oak, with most species occurring at both types of forest; however, in alder forest the epigeic species Dendrobaena octaedra was more common, whilst in oak forest the epigeic earthworms form genus Lumbricus were more abundant (L. rubellus and L. castaneus). The anecic species Aporrectodea longa was more abundant at alder sites, but L. terrestris was more abundant under oak. The alder forest was characteristic by a thick humus layer (10–15 cm), which at oak and larch sites was thinner (4–7 cm) and at pine and spruce stands was absent. Soil compaction was lower under the deciduous trees (alder, oak, larch), than under spruce and pine. We conclude that the alder plantations have most palatable litter and lowest C/N ratio and therefore support the highest numbers of soil macrofauna, which affects the humus layer thickness and soil compaction in the surface layers.

Evaluating soil biochemical/microbial indices as ecological indicators of different land use/cover in northern Iran

The objective of the study was to examine changes in microbial parameters have been used to monitor changes in soil quality under different land uses in north of Iran. The microbial parameters included microbial respiration (MR), substrate induced respiration (SIR), carbon availability index (CAI), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), ratio of MBC/MBN, metabolic quotient (qCO2) and microbial ratio were determined under different land use/cover, i.e. virgin natural forest (VNF), degraded natural forest (DNF), alder plantation (AP), sequoia plantation (SP), improved fallow (IF) and home garden (HG) areas in northern Iran. Five composed samples per land use/cover were taken from the top 10 cm of the soil. MR and SIR (0.45 and 1.66 mg CO2-C g−1 day−1, respectively) were found to be significantly higher under AP land uses than in the other areas. CAI did not differ for the land uses; MBC (591 and 590 mg kg−1, respectively) had higher significantly under SP and VNF land uses than in the other areas. MBN (64.25 and 62.33, respectively mg kg−1) was significantly higher in AP and VNF land uses, ratio of MBC/MBN (17.02) was higher in SP land use than other areas, HG had significantly higher qCO2 (0.0012 μg CO2-C mg−1 MBC day−1) and finally microbial ratio was significantly higher under IF (599.16) in comparison with HG > AP ≈ DNF > VNF > SP areas. Overall, our results indicate that AP land use (Alnus subcordata C. A. Mey.) increase of soil quality and alder plantation is suitable for rehabilitation of degraded natural forests.

Foraging behavioural traits of tropical insectivorous birds lead to dissimilar communities in contrasting forest habitats

Many deforested areas worldwide have been planted with Alnus spp. to protect watersheds and soils. However, the effects of these plantations on biodiversity are little known yet. Contrasting forest types may impose strong environmental filters to some behavioural traits, leading to dissimilar communities. Insectivorous birds are known to be sensitive to changes in habitat structure due to their specialized foraging behaviour. We contrasted species richness, abundance and composition of insectivorous birds, according to functional behaviour groups (foraging strategy and stratum), between secondary forest stands and Andean alder Alnus acuminata plantations, to assess how contrasting forest types affect this bird group in the Colombian Andes. Insectivorous bird species richness and abundance were higher at the Alder plantation rather than at the secondary forest, resulting in dissimilar communities. In this regard, forest plantations act as a positive filter for foliage gleaners and flycatchers, whereas secondary forests act as a positive filter for bark foragers. Secondary forests and alder plantations impose different ecological scenarios to insectivorous birds, related to foraging strategies and foraging stratum, which ultimately leads to a dissimilar species composition.