Pristine Forest Sites Research Articles

Biological Integrity of Azorean Native Forests Is Better Measured in Cold Season

The Azorean archipelago, recognized as one of the world’s biodiversity hotspots, is home to a diverse and unique community of arthropod species, highlighting a notable degree of endemism. However, the native forests that support these species are facing significant degradation due to habitat loss and fragmentation. In this study, we aimed to determine the ideal season for measuring the biological integrity of forest sites using a biological integrity index (IBI) based on arthropod communities captured with Sea, Land, and Air Malaise (SLAM) traps. Drawing on more than thirty years of research experience in the Azorean forests, we selected twelve reference sites, six representing preserved native forest and six representing disturbed native forest, and compared how IBI values vary between seasons. IBI values exhibited consistent variations between seasons in disturbed sites, indicating that measuring the biological integrity in these areas can be conducted at any time of the year without a specific seasonal preference. In contrast, significant differences were observed in pristine forest sites, with the winter season and the combination of winter and spring data (cold semester) showing notably higher values compared to other seasons and semesters. This finding suggests that measuring the biological integrity of preserved sites is best optimized in the cold seasons, while the detection of exotic species impact is most effective in summer and autumn. Consequently, if resources are limited, monitoring efforts should be concentrated in the winter and summer seasons to obtain the maximum and minimum values of IBI, respectively. Additionally, our study suggests that the summer season is the optimal time to detect potentially invasive exotic species.

The proper choice of proxies for relevant strontium isotope baselines used for provenance and mobility studies in glaciated terranes – Important messages from Denmark

Strontium (Sr) isotope based provenance and mobility studies of ancient humans and animals necessitate representative isoscapes/baselines. However, regions/terranes that were shaped and affected by glaciers during the last Ice Ages and are covered by glaciogenic sediments present a challenge with regards to the choice of suitable surface proxy archives. Recent studies proposed that only 87Sr/86Sr signatures from pristine areas are relevant for this purpose.To test this theory, 160 new Sr concentrations [Sr] and 87Sr/86Sr signatures composed from ~960 subsamples of soil leachates and plants, complemented with 55 surface waters from agriculturally unaffected pristine forest sites from all over Denmark (island of Bornholm excluded) were analyzed. The results reveal that average 87Sr/86Sr signatures of all three proxies (plants: 0.7115 ± 0.0025; 2σ, n = 162; soil leachates: 0.7118 ± 0.0037; 2σ; n = 161, surface waters: 0.7104 ± 0.0030; 2σ, n = 55) are elevated compared to larger water bodies (creeks, rivers, lakes). In mixing diagrams, the data converge in a shared high [Sr] low 87Sr/86Sr endmember, which points to either remnant natural carbonates and/or organic components retaining carbonate Sr in the studied Podzols/Luvisols. The indications for more abundant carbonates in the past, compared to today's acid leached soils, implies that 87Sr/86Sr values measured from pristine forest locations and heathlands do not adequately reflect the biosphere compositions that prevailed ~12,000–2000 thousand years ago. Consequently, pristine forests in Denmark seem to be unsuitable proxy archive environments for constructing Sr isotope baselines for determining the provenance and mobility of ancient humans and animals. Hence, 87Sr/86Sr values measured in these pristine areas are non-representative and inadequate, and their use will lead to wrong interpretations.Finally, our study sheds light on the complexity of defining relevant and representative isoscapes/baselines in significantly changing environments and areas where the surface biosphere conditions do not necessary reflect the underlying geology.

Long‐term legacy of land‐use change in soils from a subtropical rainforest: Relating microbiological and physicochemical parameters

AbstractTropical and subtropical ecosystems are widely affected by the expansion of agriculture over pristine lands. Despite research efforts, knowledge of the impact of land‐use change on soil is still limited by intrinsic variability, inconsistent results and inadequate replication. This study aimed to better understand the consequences of land‐use change by focusing on long‐term effects on both soil biotic and abiotic parameters. For this purpose, we selected three productive farms under similar management, each of them with pristine forest sites and agricultural sites that had been deforested for ~15 and ~30 years. In each site, we analysed soil microbiological (phospholipid fatty acids [PLFAs], biomass and activity) and physicochemical parameters. Long‐term land‐use change caused a detriment in soil microbial biomass, activity and fungal abundance, but only small changes in PLFA composition. In fact, PLFA composition was more affected by soil physicochemical properties such as carbon‐to‐nutrient ratios and labile carbon than by land use. Some physicochemical parameters (e.g., organic carbon and nutrients) were also negatively affected by land‐use change and were more sensitive to time under agricultural use than microbiological parameters. The lower sensitivity of microbiological parameters could be the result of severe drought conditions at sampling, which may have affected soil microbial communities in both land uses. We were also able to detect associations between specific microbiological and physicochemical parameters. Among these, we identified some that seemed to result from their co‐variation in response to land‐use change and others that seemed to be independent of land use. Overall, our results show that soils can suffer further deterioration several years after deforestation. In order to restore soil health in these degraded lands, we need to keep on investigating the physical, chemical and biological mechanisms responsible for this deterioration.Highlights Land‐use change affected soil microbiological and physicochemical parameters. Microbiological parameters seemed to stabilize after continuous agriculture. Soil organic C, total N and fine particles were still reduced after long‐term cultivation. Microbiological parameters were mostly associated with C‐to‐nutrient ratios and labile C. Drought conditions may have affected microbial response to land‐use change.

Сокращение площади малонарушенных лесных территорий на примере Двинско-Пинежского междуречья

Area reduction of intact forest landscapes (IFL) is one of the worldʼs problems. Disappearing of pristine forests endangers endemic species of animals that are not able to survive on the lands transformed and fragmented by human. The pristine forest site located in the European North of Russia in the Dvina-Pinega interfluve is a clear example of the forest area changed over the last 17 years. According to the World Wildlife Fund, the survival of the reindeer, which is listed in the Red Book of Russia, in Arkhangelsk region directly depends on this territory. Borders determination of IFLs is carried out by the procedures developed by environmental organizations. Medium-resolution satellite images are used to define the borders, which can be used for recognition of cuttings, burnings, and forest roads. Hereafter, the selected items are excluded from the boders of this territory. In the research, we had used layers with the previously defined (in 2000 and 2013) borders of the IFL; data on the IFL borders in 2017 were obtained through the decoding satellite images and updating the previous border in 2013. The territory of the Dvina-Pinega IFL decreased by 375 520 ha from 2000 to 2017. The reduction of this territory was directly caused by human activity, namely the ongoing logging and development of a forest road network. As the data analysis of the last 17 years has shown, the main factor negatively influencing this process is development of the road network in the region.For citation: Karpov A.A. Area Reduction of Intact Forest Landscapes on the Example of the Dvina-Pinega Interfluve. Lesnoy Zhurnal [Forestry Journal], 2019, no. 3, pp. 152–158. DOI: 10.17238/issn0536-1036.2019.3.152

Effect of reduced impact logging and small-scale mining disturbances on Neotropical stream fish assemblages

Deforestation and mining are recognized as major threats to Amazonian biodiversity, but, in addition to the well known impacts of clear cutting and industrial mining, the impact of cryptic threats such as illegal small-scale gold-mining and reduced impact logging remain little known. Here, we quantify the impact of those cryptic disturbances on a set of 201 sites dispersed throughout French Guiana. The fish assemblages of 139 pristine forest sites were compared to 16 sites subjected to reduced impact logging (i.e. selective logging), 24 sites with ongoing small-scale gold-mining and 22 sites formerly mined for gold. Controlling for the environmental variability between sites showed the significant structuring effect of all disturbances on fish taxonomic structure, with a marked impact of gold-mining. This effect was of strong magnitude and remained significant after mining activity ceased. In contrast, the reduced impact logging effect remains of low magnitude, although significant. From a functional point of view, gold-mining drives species assemblages towards a decrease in the richness of small-sized stream habitat specialist species and favours larger ubiquitous species living in both streams and rivers. Reduced impact logging effect was slighter, and negatively affected only the richness of phytophagous species. These results, encompassing a variety of hydrographic basins, unambiguously show the detrimental effect of small-scale gold-mining on fish assemblages as well as the slight effect of reduced impact logging. Since gold-mining is one of the most widespread threats throughout the Amazonian region, particular care should be given to controlling this, often illegal, activity.

Deforestation, host community structure, and amphibian disease risk

Habitat disturbances and the emergence of the chytrid fungus Batrachochytrium dendrobatidis (Bd) are linked to accelerated amphibian declines. Deforestation can directly alter amphibian community structure through abiotic and biotic mechanisms including shifts in local microclimates and species interactions. Changes in amphibian community attributes, in turn, potentially impact Bd transmission dynamics, and thus also have an indirect role in biodiversity persistence. Here, we tested whether deforestation influences Bd infections through shifts in amphibian community structure, including species richness, community composition, total host density, and host biomass. We surveyed 22 temperate and tropical amphibian communities across gradients of deforestation in the U.S. and Brazil, and we experimentally exposed a representative subsample of each amphibian community to standardized Bd zoospore loads in mesocosms under controlled microclimate. We found that denser temperate amphibian communities commonly found at pristine sites showed higher Bd loads when microclimates were held constant. In contrast, tropical amphibian communities found at pristine forest sites carried lower Bd infection loads in the absence of variable microclimates, likely due to their host species composition. Previous host exposure to the pathogen in tropical communities also played an important role in determining infection loads; we identified a negative association between Bd infection loads observed in the wild and in the laboratory. Our results highlight that deforestation can have cascading biotic effects on disease risk, and that quantifying the net contribution of host community attributes to Bd infections will help us identify specific drivers of disease and inform conservation strategies.

Tree species composition in European pristine forests: Comparison of stand data to model predictions

The degree of general applicability across Europe currently achieved with several forest succession models is assessed, data needs and steps for further model development are identified and the role physiology based models can play in this process is evaluated. To this end, six forest succession models (DISCFORM, ForClim, FORSKA-M, GUESS, PICUS v1.2, SIERRA) are applied to simulate stand structure and species composition at 5 European pristine forest sites in different climatic regions. The models are initialized with site-specific soil information and driven with climate data from nearby weather stations. Predicted species composition and stand structure are compared to inventory data. Similarity and dissimilarity in the model results under current climatic conditions as well as the predicted responses to six climate change scenarios are discussed. All models produce good results in the prediction of the right tree functional types. In about half the cases, the dominating species are predicted correctly under the current climate. Where deviations occur, they often represent a shift of the species spectrum towards more drought tolerant species. Results for climate change scenarios indicate temperature driven changes in the alpine elevational vegetation belts at humid sites and a high sensitivity of forest composition and biomass of boreal and temperate deciduous forests to changes in precipitation as mediated by summer drought. Restricted generality of the models is found insofar as models originally developed for alpine conditions clearly perform better at alpine sites than at boreal sites, and vice versa. We conclude that both the models and the input data need to be improved before the models can be used for a robust evaluation of forest dynamics under climate change scenarios across Europe. Recommendations for model improvements, further model testing and the use of physiology based succession models are made.