Bryophyte response to forest canopy treatments within the riparian zone of high-elevation small streams

Abstract

Riparian buffer strips are increasingly used to mitigate disturbance effects on terrestrial biota found adjacent to streams, yet it is unclear how the effects of canopy treatment (clear-cut, buffer, or intact forest) will interact with pre-existing stream–upland gradients. We questioned whether proximity to the stream would influence bryophyte richness and whether the effects of canopy treatment on bryophyte composition and functional group representation would differ along the stream–upland gradient. Bryophyte richness, abundance, and composition were sampled in continuous forest (n = 6), two-sided buffers (buffer width approximately 15 m on both stream sides; n = 10), and clear-cuts (n = 7) in the southern interior of British Columbia. At each site, bryophyte functional group frequency was sampled within 10 × 2 m belt transects located at 1, 5, and 10 m from the stream edge. Both distance from the stream and canopy treatment were strongly associated with bryophyte community variation. The richness of many functional groups was highest immediately adjacent to the stream. The richness and frequency of forest-associated species, as well as the overall extent of the bryophyte mat, had the highest values in continuous forests, intermediate values in buffers, and lowest values in clear-cuts. Although significant differences in bryophyte communities occurred between buffers and clear-cuts at all distances from the stream, differences between buffers and continuous forest were nonsignificant. These results indicate that riparian buffers can play an important role in the mitigation of harvesting effects on the bryologically rich communities along small headwater streams.

Bryophyte abundance, diversity and composition after retention harvest in boreal mixedwood forest

“…Feather mosses, such as Hylocomium splendens, Pleurozium schreberi, P. crista‐castrensis and the liverwort P. pulcherrimum , were identified as indicators for unharvested controls and are known to be associated with intact coniferous forest (Caners et al., ; Shields et al., ). The substantial declines in bryophyte richness in clear‐cuts that we observed initially support previous results from other forest systems in North America (Baldwin et al., ; Dovčiak et al., ) and northern Europe (Hylander & Weibull, ; Rudolphi, Jonsson, & Gustafsson, ). These effects of harvesting can be attributed to direct physical damage to both the forest floor and associated substrates (Fenton, Frego, & Sims, ) and to changes in microclimate, such as increased temperature, reduced humidity and increased light.…”

“…America (Baldwin et al, 2011;Dovčiak et al, 2006) and northern Europe (Hylander & Weibull, 2012;Rudolphi, Jonsson, & Gustafsson, 2014). These effects of harvesting can be attributed to direct physical damage to both the forest floor and associated substrates (Fenton, Frego, & Sims, 2003) and to changes in microclimate, such as increased temperature, reduced humidity and increased light.…”

Depth‐to‐water mediates bryophyte response to harvesting in boreal forests

“…Bryophytes are strongly associated with wet ground; for example Baldwin et al. () found bryophyte richness was highest in areas closest to streams. They also do well on substrates with a concave form, such as moist ground, wet ground and stream channel margins, which are characterised by being closer to the ground water table, as compared to convex substrates (e.g.…”

Bryophyte mass to stem length ratio: A potential metric for eco-physiological response to land use

“…Conceivably, semi-aquatic bryophytes may provide the most appropriate indices for anthropogenic change in many ecosystems since they are located at the terrestrial-aquatic interface, and are therefore influenced by changes occurring in both terrestrial and aquatic ecosystems. Timber harvest effects that may prove detrimental to bryophyte health include increased erosion and sediment, altered stream flow regimes, microclimate (including light availability and air and stream temperature) and nutrient regimes [11][12][13][14][15][16][17][18][19][20][21]. Given bryophyte sensitivity to disturbance, forest management including clearcutting or thinning (i.e.…”

“…A thorough review of recent primary literature concerning the effect of climatic alterations and/or timber harvest impacts on bryophytes suggested that the major-ity of studies have utilized community characteristics such as percentage cover, abundance, and various parameters of species richness and composition as measures of bryophyte response [4,6,[18][19][20][21]24,25,[27][28][29][30][31][32][33]. Of the studies that have addressed physiological and morphological responses of bryophyte species to altered climate conditions, many have focused on increased temperatures and radiation levels in Artic and sub-Artic ecosystems [34][35][36], or the response of bryophytes to increased levels of nutrients such as Nitrogen and Phosphorus [37,38].…”