scholarly journals Landscape Variables Influence over Active Restoration Strategies of Nothofagus Forests Degraded by Invasive Castor canadensis in Tierra del Fuego

2021 ◽  
Vol 13 (14) ◽  
pp. 7541
Author(s):  
Guillermo J. Martínez Pastur ◽  
Juan M. Cellini ◽  
María V. Lencinas ◽  
Yamina M. Rosas ◽  
Jonathan J. Henn ◽  
...  
Keyword(s):  
Tree Species ◽  
Abiotic Factors ◽  
Castor Canadensis ◽  
Plant Cover ◽  
Tierra Del Fuego ◽  
Natural Environments ◽  
Nothofagus Pumilio ◽  
Lower Growth ◽  
Passive Restoration ◽  
The Impact

North American beavers (Castor canadensis) are responsible for the major changes in the Tierra del Fuego Archipelago, altering riparian forests for the long-term. Passive restoration of the areas affected was ineffective in the medium-term (up to 20 years), being necessary active strategies. Plantations in abandoned ponds were made with Nothofagus pumilio and N. antarctica tree species across Tierra del Fuego island (Argentina). In the first experiment, we analysed the influence of biotic and abiotic factors in three micro-habitats in the impacted areas: front and tail of ponds, and cut not-flooded forest areas. Five-years-old N. pumilio seedlings had 39% survival in front, 21% in tails, and 46% in cut areas at year-3 of the restoration experiments, being negatively influenced by plant cover and soil moisture. Lower growth was recorded during year-1 (0.7–0.9 cm yr−1), but increased on time (1.9 cm yr−1 front, 1.6 cm yr−1 tail, 4.3 cm yr−1 cut areas). A second experiment explores the alternative to substitute the tree species to face the harder conditions of the impact and climate change. For this, we conducted a new plantation at four locations across the main bioclimatic zones, where 10–40 cm N. antarctica plants attained 17% survival in meadows (front and tail) and 30% in cut areas, being higher with larger than smaller plants (25% vs. 18%), and where they are mainly influenced by rainfall (4% in sites <400 mm yr−1 and 41% in >400 mm yr−1). The main damage was detected in the above-ground biomass due to dryness, but root survival allowed the emergence of new shoots in the following growing season. It is necessary to monitor different Nothofagus species across natural environments in the landscape to determine the feasibility and effectiveness of different strategies in restoration plans, considering the selection of climate-resilient tree species.

scholarly journals Beavers, Bugs and Chemistry: A Mammalian Herbivore Changes Chemistry Composition and Arthropod Communities in Foundation Tree Species

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 877
Author(s):  
Rachel M. Durben ◽  
Faith M. Walker ◽  
Liza Holeski ◽  
Arthur R. Keith ◽  
Zsuzsi Kovacs ◽  
...  
Keyword(s):  
Tree Species ◽  
Castor Canadensis ◽  
Habitat Type ◽  
Food Preferences ◽  
Woody Species ◽  
Juvenile Growth ◽  
Arthropod Community ◽  
Riparian Ecosystems ◽  
Arthropod Communities ◽  
The Impact

The North American beaver (Castor canadensis Kuhl) and cottonwoods (Populus spp.) are foundation species, the interactions of which define a much larger community and affect a threatened riparian habitat type. Few studies have tested the effect of these interactions on plant chemistry and a diverse arthropod community. We experimentally examined the impact of beaver foraging on riparian communities by first investigating beaver food preferences for one cottonwood species, Fremont cottonwood (P. fremontii S. Watson), compared to other locally available woody species. We next examined the impact of beaver foraging on twig chemistry and arthropod communities in paired samples of felled and unfelled cottonwood species in northern Arizona (P. fremontii) and southwestern Colorado (narrowleaf cottonwood, P. angustifolia James, and Eastern cottonwood, P. deltoides W. Bartram ex Marshall). Four major patterns emerged: (1) In a cafeteria experiment, beavers chose P. fremontii six times more often than other woody native and exotic species. (2) With two cottonwood species, we found that the nitrogen and salicortin concentrations were up to 45% greater and lignin concentration 14% lower in the juvenile resprout growth of felled trees than the juvenile growth on unfelled trees (six of seven analyses were significant for P. fremontii and four of six were significant for P. angustifolia). (3) With two cottonwood species, arthropod community composition on juvenile branches differed significantly between felled and unfelled trees, with up to 38% greater species richness, 114% greater relative abundance and 1282% greater species diversity on felled trees (six of seven analyses with P. fremontii and four of six analyses with P. angustifolia were significant). The above findings indicate that the highest arthropod diversity is achieved in the heterogenous stands of mixed felled and unfelled trees than in stands of cottonwoods, where beavers are not present. These results also indicate that beaver herbivory changes the chemical composition in 10 out of 13 chemical traits in the juvenile growth of two of the three cottonwood species to potentially allow better defense against future beaver herbivory. (4) With P. deltoides, only one of five analyses in chemistry was significant, and none of the four arthropod community analyses were significant, suggesting that this species and its arthropod community responds differently to beaver. Potential reasons for these differences are unknown. Overall, our findings suggest that in addition to their impact on riparian vegetation, other mammals, birds, and aquatic organisms, beavers also may define the arthropod communities of two of three foundation tree species in these riparian ecosystems.

scholarly journals Assessing Restoration Potential of Fragmented and Degraded Fagaceae Forests in Meghalaya, North-East India

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1008
Author(s):  
Prem Prakash Singh ◽  
Tamalika Chakraborty ◽  
Anna Dermann ◽  
Florian Dermann ◽  
Dibyendu Adhikari ◽  
...  
Keyword(s):  
Tree Species ◽  
Human Disturbance ◽  
Abiotic Factors ◽  
Anthropogenic Disturbances ◽  
Fuel Wood ◽  
Mature Trees ◽  
North East ◽  
Large Trees ◽  
Restoration Potential ◽  
The Impact

The montane subtropical broad-leaved humid forests of Meghalaya (Northeast India) are highly diverse and situated at the transition zone between the Eastern Himalayas and Indo-Burma biodiversity hotspots. In this study, we have used inventory data from seedlings to canopy level to assess the impact of both biotic and abiotic disturbances on structure, composition, and regeneration potential of the Fagaceae trees of these forests. Fagaceae trees are considered as the keystone species in these forests due to their regional dominance and their importance as a fuel wood source, and also because they form an important component of climax community in these forests. Unfortunately, these forests are highly degraded and fragmented due to anthropogenic disturbances. We have assessed, for the first time, the restoration potential (i.e., capacity to naturally regenerate and sustain desired forest structure) of Fagaceae species in the genera Lithocarpus Blume, Castanopsis (D. Don) Spach, and Quercus Linn. We also evaluated how biotic and abiotic factors, as well as anthropogenic disturbances, influence the restoration potential of these species in six fragmented forest patches located along an elevational gradient on south-facing slopes in the Khasi Hills, Meghalaya. Fagaceae was the most dominant family at all sites except one site (Laitkynsew), where it was co-dominant with Lauraceae. Fagaceae forests have shown high diversity and community assemblages. Fagaceae species had high levels of natural regeneration (i.e., seedlings and saplings) but low recruitment to large trees (diameter at breast height or DBH ≥ 10 cm) at all sites. The ability to sprout was higher in Fagaceae tree species than non-Fagaceae tree species. We have shown that human disturbance and structural diversity were positively related to regeneration of Fagaceae tree species due to high sprouting. However, with increasing human disturbance, recruitment of saplings and pole-sized trees to mature trees hampered the resulting proportion of mature Fagaceae tree species. This study provides a means for assessing regeneration and a basis for forest management strategies in degraded and fragmented forests of Meghalaya.

scholarly journals Influencia del micrositio y la exposición en la regeneración de bosques de Nothofagus pumilio afectados por Castor canadensis en Tierra del Fuego: un análisis exploratorio

2018 ◽  
Vol 39 (3) ◽  
pp. 431-440 ◽  
Author(s):  
Mónica Toro Manríquez ◽  
Álvaro Promis ◽  
Alejandro Huertas Herrera ◽  
Guillermo Martínez Pastur
Keyword(s):  
Castor Canadensis ◽  
Tierra Del Fuego ◽  
Nothofagus Pumilio

scholarly journals Soil mycobiota under managed and unmanaged forests of Nothofagus pumilio in Tierra del Fuego, Argentina

2019 ◽  
Vol 49 ◽  
Author(s):  
Lorena A. Elíades ◽  
Marta N. Cabello ◽  
Verónica Pancotto ◽  
Alicia Moretto ◽  
Natalia A. Ferreri ◽  
...  
Keyword(s):  
Management Practices ◽  
Diversity Index ◽  
Biological Indicators ◽  
Tierra Del Fuego ◽  
Nothofagus Pumilio ◽  
Management Interventions ◽  
Key Factor ◽  
And Control ◽  
The Impact ◽  
Shannon’S Diversity Index

Background: Management practices can modify the productivity of forests and the associated microbial diversity of soil. The soil mycobiota is considered a key factor in the ecological functions of forests. Forests of Nothofagus pumilio (Poepp. & Endl.) Krasser (Nothofagaceae) are the main source of timber and one of the most important economic resources in the province of Tierra del Fuego (Argentina). However, there is no information on the impact of forest management interventions for the soil mycobiota, which can be reliable biological indicators of disturbance.Methods: Fungi were isolated from samples of soil collected under several Nothofagus pumilio forests subjected to different types of management and periods of time since the intervention. Types of management were represented by harvested forest with a shelter wood cutting, stockpile area and control forest without intervention and the periods of time since intervention were 1, 5–10 and 50 years. Species richness, evenness and Shannon’s diversity index of the mycobiota in each condition of management were calculated. Additionally, the effect of seasonality was analysed.Results: The soil mycobiota was represented by 70 taxa. Richness and/or Shannon’s diversity index of the mycobiota between undisturbed forest and stockpile area were higher in May (autumn) than in September or November. There were no differences in mycobiota diversity between dates in the harvested forest.Conclusions: Our results indicate that the forest intervention per se did not negatively affect the soil culturable mycobiota composition of N. pumilio forests in Tierra del Fuego (Argentina).

Characterizing the impact of recovering sea otters on commercially important crabs in California estuaries

2020 ◽  
Vol 655 ◽  
pp. 123-137
Author(s):  
TM Grimes ◽  
MT Tinker ◽  
BB Hughes ◽  
KE Boyer ◽  
L Needles ◽  
...  
Keyword(s):  
Abiotic Factors ◽  
Sea Otter ◽  
Dungeness Crab ◽  
Sea Otters ◽  
Elkhorn Slough ◽  
Enhydra Lutris Nereis ◽  
Crab Abundance ◽  
Population Sizes ◽  
Commercially Important ◽  
The Impact

Protective legislation and management have led to an increase in California’s sea otter Enhydra lutris nereis population. While sea otter recovery has been linked to ecosystem benefits, sea otter predation may negatively affect commercially valuable species. Understanding the potential influence of sea otters is of particular importance as their range expands into estuaries that function as nurseries for commercially valuable species like Dungeness crab Metacarcinus magister. We consider how sea otter predation has affected the abundance and size of juvenile Dungeness crab in Elkhorn Slough, California, USA, and analyzed cancrid crab abundance and size across 4 California estuaries with and without sea otters to understand how biotic and abiotic factors contribute to observed variation in crab size and abundance. We compared trends in southern sea otters relative to Dungeness crab landings in California to assess whether increasing sea otter abundance have negatively impacted landings. In Elkhorn Slough, juvenile Dungeness crab abundance and size have declined since 2012, coinciding with sea otter population growth. However, the impact of sea otters on juvenile Dungeness crab size was habitat-specific and only significant in unvegetated habitat. Across estuaries, we found that cancrid crab abundance and size were negatively associated with sea otter presence. While abiotic factors varied among estuaries, these factors explained little of the observed variation in crab abundance or size. Although we found evidence that sea otters can have localized effects on cancrid crab populations within estuaries, we found no evidence that southern sea otters, at recent population sizes, have negatively impacted Dungeness crab landings in California from 2000-2014.

Actual organization of forest communities with broad-leaved trees in broad-leaved-coniferous zone (with Moscow Region as an example)

2018 ◽  
pp. 107-130 ◽  
Author(s):  
T. V. Chernenkova ◽  
O. V. Morozova ◽  
N. G. Belyaeva ◽  
M. Yu. Puzachenko
Keyword(s):  
Tree Species ◽  
Forest Cover ◽  
Activity Index ◽  
Plant Cover ◽  
Moscow Region ◽  
Pine Forests ◽  
Coniferous Forests ◽  
Oak Forests ◽  
Study Region ◽  
Spruce Forests

This study aimed at an investigation of the structure, ecology and mapping of mixed communities with the participation of spruce, pine and broad-leave trees in one of the regions of broad-leave–coniferous zone. Despite the long history of the nature use of the study area, including forestry practices (Kurnayev, 1968; Rysin, Saveliyeva, 2007; Arkhipova, 2014; Belyaeva, Popov, 2016), the communities kept the main features of the indigenous forests of the broad-leave–coniferous zone ­— the tree species polydominance of the stands, the multilayer structure of communities and the high species diversity. In the course of field works in the southwestern part of the Moscow Region (2000–2016) 120 relevés were made. Spatial structure, species composition as well as cover values (%) of all vascular plants and bryophytes were recorded in each stand. The relevés were analysed following the ecology-phytocenotic classification approach and methods of multivariate statistical analysis that allowed correctly to differentiate communities according the broad-leave species participation. The accuracy of the classification based on the results of discriminant analysis was 95.8 %. Evaluation of the similarity of the selected units was carried out with the help of cluster analysis (Fig. 12). Clustering into groups is performed according to the activity index of species (A) (Malyshev, 1973) within the allocated syntaxon using Euclidean distance and Ward’s method. The classification results are corrected by DCA ordination in PC-ORD 5.0 (McCune, Mefford, 2006) (Fig. 1). Spatial mapping of forest cover was carried out on the basis of ground data, Landsat satellite images (Landsat 5 TM, 7 ETM +, 8 OLI_TIRS), digital elevation (DEM) and statistical methods (Puzachenko et al., 2014; Chernenkova et al., 2015) (Fig. 13 а, б). The obtained data and the developed classification refine the existing understanding of the phytocenotic structure of the forest cover of the broad-leave–coniferous zone. Three forest formation groups with different shares of broad-leave species in the canopy with seven groups of associations were described: a) coniferous forests with broad-leave species (small- and broad-herb spruce forests with oak and lime (1)); broad-herb spruce forests with oak and lime (2); small- and broad-herb pine forests with spruce, lime, oak and hazel (3); broad-herb pine forests with lime, oak and hazel (4)), b) broad-leave–coniferous forests (broad-herb spruce–broad-leave forests (5)), and c) broad-leave forests (broad-herb oak forests (6), broad-herb lime forests (7)). In the row of discussed syntaxa from 1 to 7 group, the change in the ratio of coniferous and broad-leave species of the tree layer (A) reflects re­gular decrease in the participation of spruce in the plant cover (from 66 to 6 %; Fig. 3 A1, A2) and an increase in oak and lime more than threefold (from 15 to 65 %; Fig. 4 a). Nemoral species predominate in the composition of ground layers, the cove­rage of which increases (from 40 to 80 %) in the range from 1 to 7 group, the coverage of the boreal group varies from 55 to 8 % (Fig. 11) while maintaining the presence of these species, even in nemoral lime and oak forests. In forests with equal share of broad-leave and coniferous trees (group 5) the nemoral species predominate in herb layer. In oak forests (group 6) the species of the nitro group are maximally represented, which is natural for oak forests occurring on rich soils, and also having abundant undergrowth of hazel. Practically in all studied groups the presence of both coniferous (in particular, spruce) and broad-leave trees in undergrowth (B) and ground layer (C) were present in equal proportions (Fig. 3). This does not confirm the unambiguity of the enrichment with nemoral species and increase in their cover in complex spruce and pine forests in connection with the climate warming in this region, but rather indicates on natural change of the main tree species in the cenopopulations. Further development of the stand and the formation of coni­ferous or broad-leave communities is conditioned by landscape. It is proved that the distribution of different types of communities is statistically significant due to the relief. According to the results of the analysis of remote information, the distribution areas of coniferous forests with broad-leave species, mixed and broad-leave forest areas for the study region are represented equally. The largest massifs of broad-leave–coniferous forests are located in the central and western parts of the study area, while in the eastern one the broad-leave forests predominate, that is a confirmation of the zonal ecotone (along the Pakhra River: Petrov, Kuzenkova, 1968) from broad-leave–coniferous forests to broad-leave forests.

scholarly journals Effect of Competition and Climatic Conditions on the Growth of Beech in the Mixed Pine Beech Stand: Lithuanian Case Study

2020 ◽  
Vol 3 (1) ◽  
pp. 49
Author(s):  
Edgaras Linkevičius ◽  
Gerda Junevičiūtė
Keyword(s):  
Intraspecific Competition ◽  
Tree Species ◽  
Forest Growth ◽  
Competition Effect ◽  
Diameter Increment ◽  
Cart Analysis ◽  
Crown Width ◽  
Beech Stand ◽  
Negative Effect ◽  
The Impact

Climate change and warming will potentially have profound effects on forest growth and yield, especially for pure stands in the near future. Thus, increased attention has been paid to mixed stands, e.g., pine and beech mixtures. However, the interaction of tree species growing in mixtures still remains unknown. Thus, the aim of this study was to investigate the impact of the interspecific and intraspecific competition to diameter, height, and crown width of pine and beech trees growing in mixtures, as well as to evaluate the impact of climatic indicators to the beech radial diameter increment. The data was collected in 2017 at the mixed mature pine beech double layer stand, located in the western part of Lithuania. The sample plot of 1.2 hectare was established and tree species, diameter at the breast height, tree height, height-to-crown base, height-to-crown width, and position were measured for all 836 trees. Additionally, a representative sample of radial diameter increments were estimated only for the beech trees by taking out core discs at the height of 1 m when the stand was partially cut. Competition analysis was based on the distance-dependent competition index, which was further based on crown parameters. Climatic effect was evaluated using classification and regression tree (CART) analysis. We found almost no interspecific competition effect to diameter, height, or crown width for both tree species growing in the first layer. However, it had an effect on beeches growing in the second layer. The intraspecific competition effect was important for pine and beech trees, showing a negative effect for both of them. Our results show the possible coexistence of these tree species due to niche differentiation. An analysis of climatic indicators from 1991–2005 revealed that precipitation from February–May of the current vegetation year and mean temperatures from July to September expressed radial diameter increment effects for beech trees. Low temperatures during March and April, as well as high precipitation during January, had a negative effect on beech radial increments. From 2006–2016, the highest effect on radial diameter increments was the mean temperatures from July to September, as well as the precipitation in January of the current year. From 1991–2016, the highest effect on radial diameter increments was the temperature from July to September 1991–2016 and the precipitation in June 1991–2016. Generally, cool temperatures and higher precipitation in June had a positive effect on beech radial increments. Therefore, our results show a sensitivity to high temperatures and droughts during summer amid Lithuanian’s growth conditions.

scholarly journals Parasitism of Aedes albopictus by Ascogregarina taiwanensis lowers its competitive ability against Aedes triseriatus

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Emma Stump ◽  
Lauren M. Childs ◽  
Melody Walker
Keyword(s):  
Population Dynamics ◽  
Competitive Advantage ◽  
Aedes Albopictus ◽  
Abiotic Factors ◽  
Mosquito Species ◽  
Disease Spread ◽  
Aedes Triseriatus ◽  
La Crosse Virus ◽  
The Impact ◽  
Ascogregarina Taiwanensis

Abstract Background Mosquitoes are vectors for diseases such as dengue, malaria and La Crosse virus that significantly impact the human population. When multiple mosquito species are present, the competition between species may alter population dynamics as well as disease spread. Two mosquito species, Aedes albopictus and Aedes triseriatus, both inhabit areas where La Crosse virus is found. Infection of Aedes albopictus by the parasite Ascogregarina taiwanensis and Aedes triseriatus by the parasite Ascogregarina barretti can decrease a mosquito’s fitness, respectively. In particular, the decrease in fitness of Aedes albopictus occurs through the impact of Ascogregarina taiwanensis on female fecundity, larval development rate, and larval mortality and may impact its initial competitive advantage over Aedes triseriatus during invasion. Methods We examine the effects of parasitism of gregarine parasites on Aedes albopictus and triseriatus population dynamics and competition with a focus on when Aedes albopictus is new to an area. We build a compartmental model including competition between Aedes albopictus and triseriatus while under parasitism of the gregarine parasites. Using parameters based on the literature, we simulate the dynamics and analyze the equilibrium population proportion of the two species. We consider the presence of both parasites and potential dilution effects. Results We show that increased levels of parasitism in Aedes albopictus will decrease the initial competitive advantage of the species over Aedes triseriatus and increase the survivorship of Aedes triseriatus. We find Aedes albopictus is better able to invade when there is more extreme parasitism of Aedes triseriatus. Furthermore, although the transient dynamics differ, dilution of the parasite density through uptake by both species does not alter the equilibrium population sizes of either species. Conclusions Mosquito population dynamics are affected by many factors, such as abiotic factors (e.g. temperature and humidity) and competition between mosquito species. This is especially true when multiple mosquito species are vying to live in the same area. Knowledge of how population dynamics are affected by gregarine parasites among competing species can inform future mosquito control efforts and help prevent the spread of vector-borne disease.

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