Edge effects on epiphytic lichens in managed black spruce forests of eastern North America

2003 ◽  
Vol 33 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Héloïse Rheault ◽  
Pierre Drapeau ◽  
Yves Bergeron ◽  
Per-Anders Esseen
Keyword(s):  
Edge Effects ◽  
Black Spruce ◽  
Fragment Size ◽  
Forest Fragments ◽  
Epiphytic Lichens ◽  
Forest Fragment ◽  
Short Term ◽  
Edge Conditions ◽  
Interior Forest

We studied the spatial and temporal response of three epiphytic lichens (Bryoria spp., Evernia mesomorpha Nyl., and Usnea spp.) to edge effects in conifer forests of northwestern Quebec. Lichen abundance and substrate variables were sampled at four distances (5, 25, 50, and 100 m) from the edge in 15 edge–interior transects in managed black spruce (Picea mariana (Mill.) BSP) forests. Responses to edge effects were assessed for short-term (1–3 years) and long-term (8 and 16–23 years) periods. We also assessed the effect of forest fragment size on lichen abundance in 27 forest fragments ranging in size from 0.03 ha to >4 ha. We found a significant effect of distance to edge on mass of E. mesomorpha and Usnea spp. Lichen mass was lower in the first 50 m of edge compared with the forest interior (100 m). Size of forest fragments had no significant effect in any of the three lichens. However, mass of Usnea spp. was low in the seven smallest (<0.5 ha) fragments. Our results suggest that the response of epiphytic lichens to edge conditions could be used by forest managers as an indicator in determining the size of remnant stands that should be left to increase the proportion of interior forest habitat in harvested forest landscapes.

scholarly journals Small mammal glucocorticoid concentrations vary with forest fragment size, trap type, and mammal taxa in the Interior Atlantic Forest

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah A. Boyle ◽  
Noé U. de la Sancha ◽  
Pastor Pérez ◽  
David Kabelik
Keyword(s):  
Atlantic Forest ◽  
Small Mammals ◽  
Acute Stress ◽  
Physiological Stress ◽  
Fragment Size ◽  
Hair Shaft ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Trapping Methods ◽  
Free Ranging

AbstractSpecies that live in degraded habitats often show signs of physiological stress. Glucocorticoid hormones (e.g., corticosterone and cortisol) are often assessed as a proxy of the extent of physiological stress an animal has experienced. Our goal was to quantify glucocorticoids in free-ranging small mammals in fragments of Interior Atlantic Forest. We extracted glucocorticoids from fur samples of 106 small mammals (rodent genera Akodon and Oligoryzomys, and marsupial genera Gracilinanus and Marmosa) from six forest fragments (2–1200 ha) in the Reserva Natural Tapytá, Caazapá Department, Paraguay. To our knowledge, this is the first publication of corticosterone and cortisol levels for three of the four sampled genera (Akodon, Oligoryzomys, and Marmosa) in this forest system. We discovered three notable results. First, as predicted, glucocorticoid levels were higher in individuals living withing small forest fragments. Second, animals captured live using restraint trapping methods (Sherman traps) had higher glucocorticoid levels than those animals captured using kill traps (Victor traps), suggesting that hair glucocorticoid measures can reflect acute stress levels in addition to long-term glucocorticoid incorporation. These acute levels are likely due to urinary steroids diffusing into the hair shaft. This finding raises a concern about the use of certain trapping techniques in association with fur hormone analysis. Finally, as expected, we also detected genus-specific differences in glucocorticoid levels, as well as cortisol/corticosterone ratios.

scholarly journals Effects of Forest Fragment Size and Successional Stage on Mixed-Species Bird Flocks in Southeastern Brazil

The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 585-594 ◽  
Author(s):  
Marcos Maldonado-Coelho ◽  
Miguel  Marini
Keyword(s):  
Species Richness ◽  
Size Structure ◽  
Fragment Size ◽  
Southeastern Brazil ◽  
Size Analysis ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Mixed Species ◽  
Successional Stage ◽  
Mixed Species Flocks

Abstract We analyzed patterns of species richness, size, structure, and composition of mixed-species flocks in relation to forest fragment size and forest successional stage during dry and rainy seasons, at the state of Minas Gerais, southeastern Brazil. Three forest fragments (1.7, 50, and 200 ha) were used for fragment size analysis, and two fragments (200 and 300 ha) were used for successional stage analysis. Fragment size and season affected flock richness, size, stability, and composition. In the 1.7-ha fragment, flock species richness, size, and stability were significantly different only during the rainy season. Fragment successional stage also influenced flock richness and size, although season did not. Flock composition also had changes related to fragment successional stage. Fragment geometry seems to be an important factor influencing flock structure and composition.

Selection of Piceamariana for growing space efficiency

1987 ◽  
Vol 17 (5) ◽  
pp. 421-427 ◽  
Author(s):  
Laird Van Damme ◽  
William H. Parker
Keyword(s):  
Black Spruce ◽  
Basal Area ◽  
Selection Method ◽  
Stem Volume ◽  
Base Line ◽  
Short Term ◽  
Space Efficiency ◽  
Early Results ◽  
Light Interaction

In an attempt to select black spruce (Piceamariana (Mill.) B.S.P.) based on growing space efficiency, 398 candidate black spruce trees from a 60-year-old upland stand were measured for various growth and crown parameters. The best 10 trees were selected by two base lines: basal area increment vs. crown area and stem volume vs. crown radius. For comparison 10 trees were also selected by a height vs. age base line and 10 were randomly chosen to serve as a control. Only one tree was selected by all three base lines, but four other trees were selected by two of the three methods. Although discriminant analysis correctly classified 85% of the trees into the four selection and control groups, the high levels of variation associated with the growing-space efficiency base line trees made it impossible to identify a generalized form (crop ideotype) that was associated with either method. Short-term and long-term progeny tests were established to determine the relative gains associated with the different base-line selection methods. A greenhouse test was conducted over one growing season and included light intensity as a treatment; the long-term test was planted in 1984 and included spacing as a treatment. Results of the short-term test demonstrated strong family differences and strong family × light interaction, but no selection method differences or selection method × light interaction. While the long-term test was not yet mature enough to test the effect of spacing, the 2-year height growth results demonstrated strong family differences and no selection method differences. Correlation between the results of the two tests was significant (r = 0.61, P < 0.01), indicating a fairly high level of reproducibility in the juvenile progeny results. A weak, but consistent, trend of slower growth by the progeny of selected parents relative to randomly selected controls was observed. These early results suggest that if black spruce trees selected for superior growing space efficiency have inherent advantages in lower light intensities or more densely spaced situations in mature stands, their open-pollinated progeny do not express these qualities after one or two season's growth.

scholarly journals The effects of rainforest fragment area on the strength of plant–pathogen interactions

2019 ◽  
Vol 15 (1) ◽  
pp. 20180493 ◽  
Author(s):  
Ashwin Viswanathan ◽  
Jaboury Ghazoul ◽  
Ganesh Honwad ◽  
N. Arun Kumar ◽  
Robert Bagchi
Keyword(s):  
Plant Species ◽  
Species Coexistence ◽  
Fragment Size ◽  
Pathogenic Fungi ◽  
Forest Fragments ◽  
Seedling Mortality ◽  
Toona Ciliata ◽  
Plant Pathogen Interactions ◽  
Plant Species Coexistence

Pathogenic interactions between fungi and plants facilitate plant species coexistence and tropical rainforest diversity. Such interactions, however, may be affected by forest fragmentation as fungi are susceptible to anthropogenic disturbance. To examine how fragmentation affects fungus-induced seed and seedling mortality, we sowed seeds of six plant species in soils collected from 21 forest fragments. We compared seedling establishment in unmanipulated soils to soils treated with fungicides. Fungicides increased germination of Toona ciliata seeds and decreased mortality of Syzygium rubicundum and Olea dioica seedlings. The fungus-induced mortality of one of these species, S. rubicundum , decreased with decreasing fragment size, indicating that its interactions with pathogenic fungi may weaken as fragments become smaller. We provide evidence that a potential diversity-maintaining plant–fungus interaction weakens in small forest fragments and suggest that such disruptions may have important long-term consequences for plant diversity. However, we emphasize the need for further research across rainforest plant communities to better understand the future of diversity in fragmented rainforest landscapes.

scholarly journals Importance of isolated forest fragments and low intensity agriculture for the long-term conservation of the green peafowl Pavo muticus

Oryx ◽  
2020 ◽  
pp. 1-7
Author(s):  
Nay Myo Shwe ◽  
Niti Sukumal ◽  
Khin Maung Oo ◽  
Simon Dowell ◽  
Stephen Browne ◽  
...  
Keyword(s):  
Habitat Use ◽  
Agricultural Landscape ◽  
Buffer Zone ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Forest Patch ◽  
Low Intensity ◽  
Pavo Muticus ◽  
Green Peafowl

Abstract Low intensity subsistence agriculture is generally believed to be less damaging to wildlife than intensive farming. As Myanmar is undergoing rapid modernization, subsistence farming may shift to intensive agriculture, resulting in increased threats to species of conservation concern such as the green peafowl Pavo muticus. Here we investigate habitat use of the green peafowl in a low intensity agricultural landscape surrounding a small forest fragment in southern Shan State, Myanmar. The forest belongs to Nan Kone Buddha Monastery and the green peafowl is protected from hunting in the area on the basis of religious beliefs. We established three survey transects with a total length of 3,414 m. During February 2016–January 2017 we conducted surveys twice daily for 4 consecutive days every month, walking all transects in both directions in the mornings and afternoons and recording visual and auditory peafowl encounters. We estimated peafowl density to be 2.63 animals/km2 in the less disturbed western part of the study area and 1.13 animals/km2 in the eastern part, which had higher levels of human disturbance. The peafowl's habitat use was significantly non-random, with forest patches being the most utilized habitat, followed by croplands. Within a 300 m buffer zone around the forest patch, the order of habitat preference was crop > scrub > fallow, with crop significantly preferred over the other two habitats. We conclude that preserved isolated forest blocks adjacent to community-managed agricultural areas are important for green peafowl conservation, and discuss the implications for long-term conservation management of the species.

Influence of Deforestation on the Community Structure of Sand Flies (Diptera: Psychodidae) in Eastern Amazonia

2019 ◽  
Vol 56 (4) ◽  
pp. 1004-1012
Author(s):  
José Manuel Macário Rebêlo ◽  
Jorge Luiz Pinto Moraes ◽  
Gustavo Barbosa Vieira Cruz ◽  
Joudellys Andrade-Silva ◽  
Maria Da Conceição Abreu Bandeira ◽  
...  
Keyword(s):  
Community Structure ◽  
Species Composition ◽  
Significant Influence ◽  
Sand Fly ◽  
Forest Fragments ◽  
Sand Flies ◽  
Human Occupation ◽  
Short Term

Abstract Variation in the structure of phlebotomine (sand fly) communities in forest fragments with different degrees of preservation and human occupation (peridomicile) in eastern Amazonia was studied. We identified 43 species of sand flies in our study, of which 38 occurred in both preserved forest areas and in the peridomiciles of short-term settlements, while another 28 species occurred in altered forest fragments and long-term settlements. The composition of the community at each site changed with the type of environment (forest or peridomicile), with the species Lutzomyia evandroi, L. whitmani, L. choti, L. serrana, L. triacantha, L. migonei, L. hirsuta, L. shannoni, and L. brachyphylla accounting for more than 54% of the differences among environments. The quality of the environment exerted a significant influence on the structure of phlebotomine communities, and affected their species composition, richness, and abundance.

scholarly journals Contrasting long-term effects of transient anthropogenic edges and forest fragment size on generalist and specialist deadwood-dwelling fungi

2016 ◽  
Vol 54 (4) ◽  
pp. 1142-1151 ◽  
Author(s):  
Alejandro Ruete ◽  
Tord Snäll ◽  
Bengt Gunnar Jonsson ◽  
Mari Jönsson
Keyword(s):  
Fragment Size ◽  
Forest Fragment ◽  
Long Term Effects

scholarly journals The fate of tropical forest fragments

2020 ◽  
Vol 6 (11) ◽  
pp. eaax8574 ◽  
Author(s):  
Matthew C. Hansen ◽  
Lei Wang ◽  
Xiao-Peng Song ◽  
Alexandra Tyukavina ◽  
Svetlana Turubanova ◽  
...  
Keyword(s):  
Land Use ◽  
Southeast Asia ◽  
Tropical Forest ◽  
Protected Areas ◽  
Land Use Planning ◽  
Fragment Size ◽  
Biodiversity Loss ◽  
Primary Forest ◽  
Forest Fragments ◽  
Forest Fragment

Tropical forest fragmentation results in habitat and biodiversity loss and increased carbon emissions. Here, we link an increased likelihood of tropical forest loss to decreasing fragment size, particularly in primary forests. The relationship holds for protected areas, albeit with half the rate of loss compared with all fragments. The fact that disturbance increases as primary forest fragment size decreases reflects higher land use pressures and improved access for resource extraction and/or conversion in smaller fragments. Large remaining forest fragments are found in the Amazon and Congo Basins and Insular Southeast Asia, with the majority of large extent/low loss fragments located in the Amazon. Tropical areas without large fragments, including Central America, West Africa, and mainland Southeast Asia, have higher loss within and outside of protected areas. Results illustrate the need for rigorous land use planning, management, and enforcement in maintaining large tropical forest fragments and restoring regions of advanced fragmentation.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

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