Riparian bryophyte vegetation in the Cascade mountain range, Northwest U.S.A.: patterns at different spatial scales

1997 ◽  
Vol 75 (5) ◽  
pp. 744-761 ◽  
Author(s):  
Bengt Gunnar Jonsson

Riparian forests are productive and species rich ecosystems where the vegetation is structured by sharp environmental gradients. The study describes community patterns of bryophytes in stream-side forests, relates these patterns to major environmental gradients, and compares within-site factors with site level variables. Samples were collected from 360 plots 2 × 4 m in size distributed among 42 sites in old-growth Pseudotsuga–Tsuga forests. The sites ranged from 420 to 1250 m asl and stream size from 1st to 5th order streams. There were significant changes in species richness and composition along several environmental gradients. Richness within sites varied among different geomorphic surfaces with the highest number of species on areas periodically flooded. Richness was also higher in plots with high abundance of woody debris. No site level factors influenced richness at the sample plot level, while the highest species number at the site level was for large streams. The main gradients in the species composition within sites were changes with increasing distance from the stream and amount of woody debris. Both elevation and stream size significantly influenced species composition. The complex set of factors that influenced species richness and composition implies that management of riparian vegetation must be based on both coarse scale considerations such as regional distribution of different stream types and fine scale factors such as spatial availability of different substrate types. Key words: old-growth forest; CCA analysis; fluvial disturbance; bryophytes; elevation effects; coarse woody debris.

2021 ◽  
Vol 4 ◽  
Author(s):  
Jeffrey Opoku-Nyame ◽  
Alain Leduc ◽  
Nicole J. Fenton

Clear cut harvest simplifies and eliminates old growth forest structure, negatively impacting biodiversity. Partial cut harvest has been hypothesized (1) to have less impact on biodiversity than clear cut harvest, and (2) to encourage old growth forest structures. Long-term studies are required to test this hypothesis as most studies are conducted soon after harvest. Using epixylic bryophytes as indicators, this study addresses this knowledge gap. Fourteen years after harvest, we examined changes in epixylic bryophyte community composition richness and traits, and their microhabitats (coarse woody debris characteristics and microclimate) along an unharvested, partial cuts and clear cuts harvest treatment in 30 permanent plots established in the boreal black spruce (Picea mariana) forests of northwestern Quebec, Canada. Our results were compared to those of an initial post-harvest study (year 5) and to a chronosequence of old growth forests to examine species changes over time and the similarity of bryophyte communities in partial cut and old growth forests. Coarse woody debris (CWD) volume by decay class varied among harvest treatments with partial cuts and clear cuts recording lower volumes of early decay CWD. The epixylic community was richer in partial cuts than in mature unharvested forests and clear cuts. In addition, species richness and overall abundance doubled in partial and clear cuts between years 5 and 14. Species composition also differed among treatments between years 5 and 14. Furthermore, conditions in partial cut stands supported small, drought sensitive, and old growth confined species that are threatened by conditions in clear cut stands. Lastly, over time, species composition in partial cuts became more similar to old growth forests. Partial cuts reduced harvest impacts by continuing to provide favorable microhabitat conditions that support epixylic bryophytes. Also, partial cut harvest has the potential to encourage old growth species assemblages, which has been a major concern for biodiversity conservation in managed forest landscapes. Our findings support the promotion of partial cut harvest as an effective strategy to achieve species and habitat conservation goals.


2019 ◽  
Vol 5 (3) ◽  
pp. eaau3114 ◽  
Author(s):  
Danaë M. A. Rozendaal ◽  
Frans Bongers ◽  
T. Mitchell Aide ◽  
Esteban Alvarez-Dávila ◽  
Nataly Ascarrunz ◽  
...  

Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes.


2003 ◽  
Vol 33 (5) ◽  
pp. 763-769 ◽  
Author(s):  
Robert N Muller

Forest disturbance was evaluated in an old-growth forest on the Cumberland Plateau in southeastern Kentucky using a 10-year history of coarse woody debris (CWD) accumulation. CWD averaged 21.8 Mg/ha in 1989 and 29.6 Mg/ha (36% increase) in 1999. In both years, Quercus montana Willd. and Fagus grandifolia Ehrh. were the two dominant components of CWD; however, over the 10-year interval, Tilia heterophylla Vent., Carya glabra (Mill.) Sweet, and Acer saccharum Marsh. increased significantly, while Quercus alba L. declined. CWD occurrence had a highly skewed frequency, which is consistent with the idea that gap dynamics dominate the disturbance patterns of temperate old-growth forests. However, CWD composition bore limited relationship to overstory species composition or to the dynamics of gap creation. Further, while CWD showed no relationship to forest community (i.e., landscape position) in 1989, it was strongly related to community in 1999. The increase in CWD mass and changing importance of landscape position appear to have occurred in the absence of extrinsic disturbance factors. Thus, in old-growth deciduous forests of the temperate region, autogenic disturbance appears to occur at two scales: (i) the patch dynamics of individual tree mortality and (ii) landscape-scale patterns of mortality that are determined by species composition and differing patterns of mortality among species.


1983 ◽  
Vol 7 (4) ◽  
pp. 208-212 ◽  
Author(s):  
Robert N. Muller

Abstract An old-growth forest and a 35-year-old, second-growth forest on the Cumberland Plateau were studied to compare species composition and structure. Species composition and total basal area of the two stands did not differ, although total stand density was 19 percent lower and basal area of commercial species was 25 percent higher in the old-growth than in the second-growth stand. Analysis of size-class distributions showed that both stands were best represented by an inverse J-shaped distribution, which best describes old-age stands. The rapid regeneration of the second-growth stand seems to be the result of minimal disturbance to accumulated nutrient pools in the soil. The importance of these accumulated nutrient pools and implications for forest management on the Cumberland Plateau are discussed.


2006 ◽  
Vol 54 (3) ◽  
pp. 239 ◽  
Author(s):  
P. A. M. Turner ◽  
J. B. Kirkpatrick ◽  
E. J. Pharo

The species richness and species composition of bryophytes (mosses and liverworts) was recorded at 33 sites in Tasmanian old growth mixed eucalypt forest. A total of 202 bryophyte taxa were recorded, consisting of 115 liverworts and 87 mosses. This constitutes approximately one third of the total bryophyte flora for Tasmania. Mean liverwort species richness per site was higher than moss species richness. Latitude was found to be a positive predictor in all multiple regression models of bryophyte, moss and liverwort species richness. Mean annual temperature and rainfall of the driest month were positive predictors for bryophyte and liverwort species richness. Basal area of the treefern Dicksonia antarctica Labill. was a negative predictor of liverwort species richness. Latitude, variables relating to moisture, mean annual temperature, rainfall of the driest month and basal area of Dicksonia antarctica were the most significant components in predicting variation in bryophyte, moss and liverwort species composition. There were few relationships between the variables of canopy cover and soil nutrients and bryophyte species richness and composition. Substrate variables were found to be important components in predicting variation in moss and bryophyte species composition.


Herpetozoa ◽  
2020 ◽  
Vol 33 ◽  
pp. 95-111
Author(s):  
Christian E. Supsup ◽  
Augusto A. Asis ◽  
Uldarico V. Carestia Jr ◽  
Arvin C. Diesmos ◽  
Neil Aldrin D. Mallari ◽  
...  

Information on species richness and community structure is invaluable for guiding conservation and management of biodiversity, but is rarely available in the megadiverse biodiversity conservation hotspot of Philippines – particularly for amphibians and reptiles. This study provides the first report and characterisation of amphibians and reptile communities across primary habitat types of the Victoria-Anepahan Mountain Range on Palawan Island along the western edge of the archipelago. A total of 41 amphibian and reptile species were recorded throughout our sampling sites (n = 27 species) or in targeted habitat searches (14 species). A species richness estimator predicted that 35 species may be present in our sampling sites, suggesting that a significant proportion of secretive species may continue to be unrecorded, especially for reptiles. Higher species richness was found in secondary growth than in mixed-use agricultural areas or even pristine forest. The low species richness recorded from pristine forest types may be due to these forests now being restricted to higher elevations where species diversity has been documented to decrease. Our results also show that complex community structures (species assemblages) are to be equally expected in both secondary growth and pristine forests. Together, our results show how species richness and community assemblages may vary across habitats, highlighting that old growth forest does not always support higher species richness, particularly in high elevations.


2010 ◽  
Vol 259 (8) ◽  
pp. 1666-1672 ◽  
Author(s):  
Fang-Fang Yang ◽  
Yue-Lin Li ◽  
Guo-Yi Zhou ◽  
K.O. Wenigmann ◽  
De-Qiang Zhang ◽  
...  

2017 ◽  
Vol 149 (4) ◽  
pp. 444-460 ◽  
Author(s):  
Jindřich Roháček ◽  
Stephen A. Marshall

AbstractVolumosinanew genus (Diptera: Sphaeroceridae: Limosininae) is described to accomodate the enigmatic Nearctic species Herniosina voluminosa Marshall, 1987 and its relationships are discussed. Based on morphological characters Volumosina is treated as part of the Limosina genus group along with Apteromyia Vimmer, 1929, Gigalimosina Roháček, 1983, Herniosina Roháček, 1983, and Limosina Macquart, 1835 but its position within the group remains unresolved. Volumosina voluminosa (Marshall, 1987) new combination is recorded from Canada and redescribed with new distributional and natural history data suggesting that it is an old-growth specialist associated with large woody debris. The gigantism of the male aedeagal complex of V. voluminosa is discussed.


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