Changes in epiphyte diversity in declining forests: implications for conservation and restoration

Abstract

Biodiversity degradation is a serious global problem, and conservation or restoration has been conducted in various ecosystems. The objective of this study was to examine effective conservation measures and restoration goals for epiphytes on the basis of changes in epiphyte flora during the past 30 years on Mt. Odaigahara, Japan. Comparison of epiphyte diversity between 1983 and 2008 indicated that species richness and cover in plots surveyed in 1983 had declined significantly by 2008. The results of nonmetric multidimensional scaling showed that the dominance of hygrophilous species decreased on trees surveyed in 2008 accompanied with forest decline. In addition, total species richness decreased with increasing coverage of wire mesh installed for protection against debarking by deer. We conclude that severe drought stress caused by forest decline after the 1980s and the toxic effects of wire mesh on epiphytes have led to a dramatic decrease in epiphyte diversity during the past 30 years. To conserve epiphyte diversity, first, tree protection without wire mesh should be adopted. In addition, intensive conservation of undamaged forest patches may be necessary to prevent loss of remaining hygrophilous species from this region. The results also indicate that epiphyte diversity can be strongly affected by slight changes in forest structure, and by site-specific environmental factors. Considering that these changes or environmental factors are often not easy to evaluate, comparison of epiphyte diversity before and after disturbance can be an important means of determining appropriate restoration objectives.

Exotic weeds and fluctuating microclimate can constrain native plant regeneration in urban forest restoration

“…Two indicators of successful restoration of temperate rainforests are regeneration of long-lived, shade-tolerant trees (Suganuma andDurigan 2015, Johnson andHandel 2016) and colonization by epiphytes (Oishi andDoei 2015, Reid et al 2016). Spontaneous dispersal and recruitment of these indigenous, late successional plants into a forest undergoing restoration is an indication that conditions have become suitable for natural forest dynamics to occur without additional management actions (Robinson and Handel 1993, Boudreault et al 2000, Shoo et al 2015, Bertacchi et al 2016.…”

Germination fitness of two temperate epiphytic ferns shifts under increasing temperatures and forest fragmentation

“…The combined impacts of multiple stresses on plant physiology can exponentially impact species biology [ 21 ]. The loss of tropical and temperate primary forests is linked to the disappearance of moist-sensitive fern epiphytes [ 25 , 40 ]. This could also happen in our case, as we have observed that well-structured non-fragmented forests seem to smooth the reduction of maximum germination or the delay in the onset of germination, due to increasing temperatures.…”

“…Regarding germination, epiphytes are affected by increasing temperatures due to global warming [ 17 , 19 , 21 ]. Forest structure related to fragmentation is also linked to epiphytic abundance as well-structured complex forests generate more buffered micro-conditions which maintain suitability for the epiphytic habit [ 20 , 22 , 24 , 25 ]. The loss of forest structure due to fragmentation and clearness of the canopy affects, at least, epiphytic community composition by reducing individuals of intolerant species and promoting new suitable opportunities to tolerant ones [ 19 , 26 ].…”

A comparison of species composition and community assemblage of secondary forests between the birch and pine-oak belts in the mid-altitude zone of the Qinling Mountains, China

“…Rapid changes in forest landscapes due to urbanization, agriculture, road construction, and especially deforestation have caused forest loss and fragmentation, threatening forest biodiversity worldwide ( Elliott & Swank, 1994 ; Imai et al, 2014 ; Jung et al, 2014 ). Urgent intervention for conserving biodiversity and forest remnants is thus necessary ( Jactel & Brockerhoff, 2007 ; Nyafwono et al, 2014 ; Oishi & Doei, 2015 ).…”