Avian Use of Restoration Plantings along a Creek Linking Rainforest Patches on the Atherton Tablelands, North Queensland

Rainforest fragmentation and creek degradation are major problems on the Atherton Tablelands in North Queensland. Lake Barrine and Wooroonooran National Parks are separated by a 1.5‐km length of Toohey's Creek which has been cleared except for small remnant rainforest patches. The creek has been fenced and replanted to create a corridor between the two national parks. The aim of this study was to monitor the success of the corridor in providing habitat for rainforest birds. Avian communities were monitored in the corridor and in adjacent rainforest sites using point counts over the period of reestablishment of a continuous rainforest canopy. In terms of bird community composition, within 3 years of planting, the replanted sites were on a trajectory toward the rainforest sites. Although specialist rainforest species were not yet found in the plantings, after 3 years those species which mainly inhabit rainforest but also utilize edges and riparian strips were found in similar numbers in the plantings and in the small remnant patches along the corridor. Frugivorous species were quite abundant even in the youngest plantings. Thus, replanting of rainforest trees along Toohey's Creek has begun to provide habitat for some rainforest birds. It also shows good potential to act as a corridor to connect the previously isolated patches of rainforest for these species and to develop in habitat complexity as the frugivorous birds bring in rainforest plant species from nearby areas.     

Recovery of rain forest soil seed banks under different reforestation pathways in eastern Australia

Summary Seed availability is a major factor limiting the recruitment of rain forest to cleared land, but little is known about the composition of the soil seed bank under different reforestation pathways. We quantified changes in the viable soil seed bank following rain forest clearing and pasture establishment and subsequent reforestation in subtropical eastern Australia. Major reforestation pathways in the region include planting of a diverse suite of native trees for ecological restoration purposes, autogenic regrowth dominated by the non‐native tree Camphor Laurel (Cinnamomum camphora) and management of this regrowth to accelerate the development of a native tree community. These pathways differ considerably in cost: restoration plantings are expensive, autogenic regrowth is free, whilst managing regrowth generally costs much less than restoration plantings. We surveyed five sites within each of three reforestation pathways as well as reference sites in remnant rain forest and pasture. The composition of the seed bank was determined by germinating plants from soil samples collected from each site. Germinants were classified into several functional groups according to life form, origin, dispersal mode and successional stage. The majority of functional groups varied significantly in abundance or richness between rain forest and pasture sites. Most of the functional groups that varied between rain forest and pasture were restored to values similar to rain forest by at least one of the three reforestation pathways examined. The species richness of native woody plants in the soil seed bank was slightly higher in restoration plantings than in autogenic or managed regrowth; nevertheless, the species richness and abundance of native woody plants and vines were higher in the seed bank of autogenic regrowth than pasture, and both attributes were enhanced by the management of regrowth sites. The results of this study show that autogenic regrowth can make an important contribution to rain forest restoration at a landscape scale. The optimal reforestation approach or mix of approaches will depend on the desired rate of recovery and the resources available for restoration.     

Responses of ground-active beetle assemblages to different styles of reforestation on cleared rainforest land

Despite increasing efforts to re-establish forest cover in landscapes that have been previously cleared, the relative ability of different styles of reforestation to contribute to conservation and support forest biota is poorly known, particularly for invertebrates. We investigated the use of different types of reforested habitat by ground-active rainforest beetle assemblages on land, which had been previously cleared of rainforest, in the tropics and subtropics of eastern Australia. Between five and ten replicate sites within each of five reforestation styles were selected in each region: un-managed regrowth, young mono-species timber plantations, young mixed-species timber plantations, ecological restoration plantings, and old mono-species timber plantations, together with reference sites in pasture and in intact rainforest. Ground-active beetles were sampled using pitfall traps, and assemblages were compared among site-types. In both regions, beetle assemblages in all styles of reforestation were intermediate in species composition between pasture and rainforest. The similarity of beetle assemblages to intact rainforest increased with the age and structural complexity of reforested sites. The most rainforest-like beetle assemblages were from older reforestation sites (38–70 year plantations in tropics, and 30–40 year regrowth in subtropics) and in younger (6–22 years) but floristically and structurally diverse ecological restoration plantings in both regions. Assemblages in younger (5–20 year) sites of regrowth, mono-species timber plantations, and mixed-species timber plantations were more similar to pasture than rainforest. We conclude that achieving high canopy cover and sufficient structural complexity are important factors associated with the restoration of rainforest-like beetle assemblages to reforested sites.     

Reforestation with native mixed‐species plantings in a temperate continental climate effectively sequesters and stabilizes carbon within decades

Reforestation has large potential for mitigating climate change through carbon sequestration. Native mixed‐species plantings have a higher potential to reverse biodiversity loss than do plantations of production species, but there are few data on their capacity to store carbon. A chronosequence (5–45 years) of 36 native mixed‐species plantings, paired with adjacent pastures, was measured to investigate changes to stocks among C pools following reforestation of agricultural land in the medium rainfall zone (400–800 mm yr^?1) of temperate Australia. These mixed‐species plantings accumulated 3.09 ± 0.85 t C ha^?1 yr^?1 in aboveground biomass and 0.18 ± 0.05 t C ha^?1 yr^?1 in plant litter, reaching amounts comparable to those measured in remnant woodlands by 20 years and 36 years after reforestation respectively. Soil C was slower to increase, with increases seen only after 45 years, at which time stocks had not reached the amounts found in remnant woodlands. The amount of trees (tree density and basal area) was positively associated with the accumulation of carbon in aboveground biomass and litter. In contrast, changes to soil C were most strongly related to the productivity of the location (a forest productivity index and soil N content in the adjacent pasture). At 30 years, native mixed‐species plantings had increased the stability of soil C stocks, with higher amounts of recalcitrant C and higher C : N ratios than their adjacent pastures. Reforestation with native mixed‐species plantings did not significantly change the availability of macronutrients (N, K, Ca, Mg, P, and S) or micronutrients (Fe, B, Mn, Zn, and Cu), content of plant toxins (Al, Si), acidity, or salinity (Na, electrical conductivity) in the soil. In this medium rainfall area, native mixed‐species plantings provided comparable rates of C sequestration to local production species, with the probable additional benefit of providing better quality habitat for native biota. These results demonstrate that reforestation using native mixed‐species plantings is an effective alternative for carbon sequestration to standard monocultures of production species in medium rainfall areas of temperate continental climates, where they can effectively store C, convert C into stable pools and provide greater benefits for biodiversity.     

Biodiversity recovery during rainforest reforestation as indicated by rapid assessment of epigaeic ants in tropical and subtropical Australia

There is growing interest in the potential for reforestation to assist the recovery of rainforest biodiversity. There is also a need to identify taxonomically tractable groups for use as cost‐effective indicators when monitoring the status of biodiversity within reforested sites. Insects are an important component of terrestrial biodiversity but often require considerable resources to sample at species level. Ant genera and generic‐based functional groups have been suggested as possible indicators of environmental disturbance. Here we ask to what extent the development of biodiversity is indicated by epigaeic ant genera and functional groups, across different types of reforestation in tropical and subtropical Australia. In each region, we used pitfall traps to sample the ants in replicate sites of: unmanaged regrowth, monoculture and mixed species plantations and ‘ecological restoration’ plantings, together with reference sites in pasture and rainforest. We recorded 35 epigaeic ant genera (and 4623 individuals) from 50 tropical sites, and 39 genera (and 9904 individuals) from 54 subtropical sites, with 47 genera overall. Community composition of both genera and functional groups differed between pasture and rainforest, although many genera were widespread in both. Reforested sites were intermediate between pasture and rainforest in both regions, and showed a gradient associated with decreasing grass and increasing tree and litter cover. Older monoculture plantations and ecological restoration plantings had the most rainforest‐like ant assemblages, and mixed‐species cabinet timber plots the least, of the reforested sites. We conclude that ground‐active ant genera and functional groups sampled in rapid surveys by pitfall‐trapping showed only a modest ability to discriminate among different types of reforestation. Species‐level identification, perhaps together with expanded sampling effort, could be more informative, but would require resourcing beyond the scope of rapid assessments.     

Carbon stocks in above‐ground biomass of monoculture plantations,mixed species plantations and environmental restoration plantings in north‐east Australia

Summary The emergence of carbon markets has provided a potential source of funding for reforestation projects. However, there is concern amongst ecologists that these markets will promote the establishment of monoculture plantations rather than more diverse restoration plantings, on the assumption that fast‐growing monocultures are likely to store more carbon than restoration plantings. We examined the validity of this assumption for three predominantly rainforest plantation types established in the moist tropical uplands of north‐east Australia: monoculture plantations of native rainforest conifers (n = 5, mean age 13 years); mixed species plantations of rainforest cabinet timber species, rainforest conifers and eucalypts (n = 5, mean age 13 years); and, environmental restoration plantings comprised mostly of a diverse range of rainforest trees (n = 10, mean age 14 years). We found that restoration plantings stored significantly more carbon in above‐ground biomass than monoculture plantations of native conifers (on average, 106 t vs 62 t carbon per ha); and tended to store more carbon than mixed species timber plantations which were intermediate in value (86 t carbon per ha). Carbon stocks were higher in restoration plantings than in monoculture and mixed species plantations for three reasons. First, and most importantly, restoration plantings were more densely stocked than monoculture and mixed species plantations. Second, there were more large diameter trees in restoration plantings than monoculture plantations. Third, the trees used in restoration plantings had a higher average wood density than the conifers used in monoculture plantations. While, on average, wood density was higher in mixed species plantations than restoration plantings, the much higher stocking rate of restoration plantings meant they stored more carbon than mixed species plantations. We conclude that restoration plantings in the moist tropics of north‐east Australia can accumulate relatively high amounts of carbon within two decades of establishment. Comparison with reference rainforest sites suggests that restoration plantings could maintain their high stocking rates (and therefore high biomass) as they develop in future decades. However, because restoration plantings are currently much more expensive to establish than monoculture plantations, restoration plantings are unlikely to be favoured by carbon markets. Novel reforestation techniques and designs are required if restoration plantings are to both provide habitat for rainforest biota and store carbon in biomass at a cost comparable to monoculture plantations.     

Factors Affecting the Use of Reforested Sites by Reptiles in Cleared Rainforest Landscapes in Tropical and Subtropical Australia

Despite recent efforts to reforest cleared rainforest landscapes, in Australia and elsewhere, the value of reforested sites for rainforest‐dependent reptiles is unknown. We surveyed the occurrence of reptiles in a range of reforestation types (monoculture and mixed‐species timber plantations, diverse “ecological restoration” plantings and regrowth), as well as reference sites in pasture and rainforest, in tropical and subtropical Australia. We recorded 29 species of reptiles from 104 sites, including 15 rainforest‐dependent species. Most rainforest reptiles were strongly associated with complex microhabitats (tree trunks, logs, rocks). The richness and abundance of rainforest‐dependent reptiles varied between the different types of reforestation and between regions. In the tropics, rainforest reptiles were recorded in old timber plantations and ecological restoration plantings but not in young timber plantations or regrowth. Rainforest reptiles were recorded in few reforested sites in the subtropics. The occurrence of rainforest‐dependent reptiles in reforested sites appears to be influenced by (1) habitat structure; (2) proximity to source populations in rainforest; and (3) biogeography and historical differences in the extent of rainforest. Restoration of cleared land for rainforest‐dependent reptiles may require the development, or deliberate creation, of complex structural attributes and microhabitats in reforested sites. Where reforested sites are located away from rainforest, recolonization by rainforest reptiles may require the construction of corridors of suitable habitat between reforested sites and rainforest or the translocation of reptiles to reforested sites.     

Response of soil microbial biomass and activity in early restored lands in the northeastern Brazilian Atlantic Forest

Intensive land use of the Brazilian Atlantic Forest accelerated with the rise of sugar cane plantations in the northeastern part of Brazil. Consequently, many ecosystems were destroyed, including riparian forests. The number of studies of riparian restoration has increased but comparative studies on the belowground effects of common reforestation strategies are rare. Here, we compared soil microbial properties among four different land use types: native rainforest, sugar cane plantation, single species reforestation, and mixed species reforestation, each replicated at two spatially independent sites. Soil samples were taken in 2013 and 2014, that is 2 and 3 years after reforestation, respectively. In both years, land use types had a significant effect on basal respiration, microbial biomass, and specific respiration (whereas specific respiration was marginally affected in 2014). In 2013, basal respiration in sugar cane plantations was significantly lower (?65%) when compared to native forests. In 2014, basal respiration (+60%) and soil microbial biomass (+90%) were significantly higher in mixed species reforestation compared to sugar cane, whereas single species reforestation had comparable values as in sugar cane plantations. Our results indicate that soil microbial biomass and activity respond rapidly to land use change when mixed species reforestation is used. Thus, using mixed species reforestation may enhance the provisioning of ecosystem services already in the short term.     

Fauna community trends during early restoration of alluvial open forest/woodland ecosystems on former agricultural land

Vertebrate fauna was studied over 10 years following revegetation of a Eucalyptus tereticornis ecosystem on former agricultural land. We compared four vegetation types: remnant forest, plantings of a mix of native tree species on cleared land, natural regeneration of partially cleared land after livestock removal, and cleared pasture land with scattered paddock trees managed for livestock production. Pasture differed significantly from remnant in both bird and nonbird fauna. Although 10 years of ecosystem restoration is relatively short term in the restoration process, in this time bird assemblages in plantings and natural regeneration had diverged significantly from pasture, but still differed significantly from remnant. After 10 years, 70 and 66% of the total vertebrate species found in remnant had been recorded in plantings and natural regeneration, respectively. Although the fauna assemblages within plantings and natural regeneration were tracking toward those of remnant, significant differences in fauna between plantings and natural regeneration indicated community development along different restoration pathways. Because natural regeneration contained more mature trees (dbh > 30 cm), native shrub species, and coarse woody debris than plantings from the beginning of the study, these features possibly encouraged different fauna to the revegetation areas from the outset. The ability of plantings and natural regeneration to transition to the remnant state will be governed by a number of factors that were significant in the analyses, including shrub cover, herbaceous biomass, tree hollows, time since fire, and landscape condition. Both active and passive restoration produced significant change from the cleared state in the short term.     

Photosynthetic Responses to Light for Rainforest Seedlings Planted in Abandoned Pasture, Costa Rica

Efforts to reforest tropical pasture with native tree species have increased in recent years, yet little is known about the physiology of most tropical trees. The goal of this study was to assess the effect of habitat on photosynthetic responses to light for seedlings of four native rainforest species (Calophyllum brasiliense, Ocotea glaucosericea, Ocotea whitei, and Sideroxylon portoricense) planted to facilitate tropical rainforest recovery in southern Costa Rica. Seedlings were planted in primary forest, in open abandoned pasture, and in the shade of remnant trees within the pasture. Growth, morphology, photosynthetic gas exchange responses to light, and chlorophyll fluorescence (an indication of the integrity of photosynthetic processes) were measured in the three habitats. Height and leaf area were generally greater for seedlings in tree shade compared to those in the forest and open pasture. Photosynthetic rates were higher for plants in open pasture and tree shade compared to those in the forest for two of the four species. Chlorophyll fluorescence results indicated flexibility in the photosynthetic processing of light energy that may help plants tolerate the bright light of the pasture. This study demonstrates that, for certain species, seedlings under remnant pasture trees do not exhibit the level of photosynthetic stress experienced in open abandoned pasture. Seedling responses to light, in combination with other factors such as increased nutrient input through litterfall, help explain the enhanced growth of seedlings under remnant pasture trees. Planting seedlings under remnant trees may increase the success of future efforts to restore tropical forest in abandoned agricultural land.     

Rainforest seed rain into abandoned tropical Australian pasture is dependent on adjacent rainforest structure and extent

It is well known that the recovery of abandoned tropical pastures to secondary rainforest benefits from the arrival of seeds from adjacent rainforest patches. Less is known, however, about how the structural attributes of adjacent rainforest (e.g. tree density, canopy cover and tree height) impact seed rain patterns into abandoned pastures. Between 2011 and 2013, we used seed traps and ground seed surveys to track the richness and abundance of rainforest seeds entering abandoned pastures in Australia's wet tropics. We also tested how seed rain diversity is related to the distance from forest, the proportion of forest cover in the landscape and several structural attributes of adjacent forest patches, specifically average tree height, canopy cover, tree species richness and density. Almost no seeds were captured in elevated pasture seed traps, even near forest remnants. Abundant forest seeds were found in ground surveys but only within 10 m of forest edges. In ground surveys, seeds from wind‐dispersed species were more abundant, but less species rich, than animal‐dispersed species. A survey of pasture seedling recruits suggested that some forest seeds must be dispersing more than 10 m into pasture at very low frequencies, but only a few species are establishing there. Recruits were predominantly animal‐dispersed not wind‐dispersed species. In addition to distance from forest and the proportion of forest within a 100‐ to 200‐m radius of sampling sites, the richness and density of adjacent forest trees were the most important factors for explaining the probability of seed occurrence in abandoned pastures. Results suggest that without some restoration assistance, the recovery of abandoned pastures into secondary rainforest in Australia's tropical rainforests will likely be limited, at least in part, by a very low rate of seed dispersal away from forest edges and by the diversity and density of trees in adjacent remnant forests.     

Facilitating the restoration of aquatic plant communities in a Ramsar wetland

Human activities such as land clearing and intensive land use around water bodies, particularly wetlands, have a detrimental impact on water quality and quantity, aquatic plant communities, and associated wetland fauna. Lake Alexandrina and Lake Albert are internationally significant Ramsar wetlands located at the terminus of the Murray River, Australia's longest river system. Agriculture, water regulation, and extraction and droughts have had a detrimental impact on native plant communities in the lakes. We studied the influence of young (<1–3 years) and old (8–11 years) plantings of a native sedge (bulrush), Schoenoplectus tabernaemontani, to facilitate the establishment of aquatic plant communities in comparison with remnant and control sites. We also measured how planting structure (height, stand width, and stem density) changed with age in comparison with remnant sites. Results suggest that as plantings age they get substantially wider and have a greater maximum height, although do not reach similar stand widths by 11 years when compared to remnant areas. However, old plantings do not differ from remnant habitats in relation to aquatic plant species richness, counts of aquatic plants, and community composition. Young plantings have substantially less abundant and diverse plant communities, but are developing on a similar trajectory to old plantings. It is likely that planting sedges along lake shorelines causes a breakwater effect that facilitates the recolonization of wetland plants between the planted area and the water's edge. Management agencies should consider restoring native sedges to increase aquatic biodiversity, and potentially reduce erosion.     

Land use impacts on physical properties of 28 years old reclaimed mine soils in Ohio

Reclamation enhances soil quality by improving physical and chemical properties, which helps in restoration of mine soils. Evaluation of the effects of post-reclamation land uses on physical and chemical properties of mine soils helps to identify suitable land uses for mining companies. The objectives of this study were to evaluate the effects of post-reclamation land uses (e.g., forest, hay and pasture) on selected physical properties of soil in relation to undisturbed forest and agricultural land use. Soil samples were collected from the 0- to 5-, 5- to 15- and 15- to 30-cm depths in order to determine particle size distribution, bulk density, water-stable aggregates, mean-weight diameter and soil moisture retention. Cone index and infiltration rate were determined at soil surface. After 28 years of reclamation, bulk density in the surface layer of all land uses in the reclaimed mine soil (RMS) was similar to that of undisturbed forest (1.1 Mg m⁻³) but lower than that of agricultural soils (1.3 Mg m⁻³). However, soil bulk density at lower depths was not affected. The cone index was higher in the RMS-pasture (2.6 MPa) than the RMS-forest (1.4 MPa) and RMS-hay (1.5 MPa) due to the trampling effect of grazing animals. The water-stable aggregates (>2 mm), of 5–8 mm aggregates, were higher in RMS-forest by 24%, 90%, 66%, and under RMS-hay by 13%, 74%, 43% for the 0- to 5-, 5- to 15-, and 15- to 30-cm depths, respectively, than that under undisturbed forest. The mean-weight diameter (0- to 30-cm) of aggregates under RMS-forest and RMS-hay were higher than that under undisturbed forest by 41% and 27%, respectively. The initial infiltration rates at 5 min in RMS under forest, hay and pasture were less by 20%, 53% and 85%, respectively, than that under undisturbed forest (19.3 cm min⁻¹). The reclamation of mine soils with forest and hay improved surface soil bulk density and cone index, and enhanced water infiltration capacity and water-stable aggregates at the lower depths. Therefore, establishment of forest and hay should be encouraged in the RMS.     

Monarch butterfly host plant (milkweed Asclepias spp.) abundance varies by habitat type across 98 prairies

The decline in migratory monarch butterflies (Danaus plexippus) over the past 20 years has been attributed to several drivers, including loss of their host plants (milkweeds Asclepias spp.). This has sparked widespread interest in milkweed ecology and restoration. We developed a model on environmental and habitat‐type variables to predict milkweed abundance by sampling 93 prairie plantings (47 conservation plantings and 46 roadsides) and 5 unplowed prairie remnants throughout the state of Iowa, United States. Milkweeds were censused in 10–25 random locations within each site, and data on plant diversity, age of planting, soil characteristics, and management were tested as predictors of abundance. Milkweed densities of all species combined were highest in remnant prairies (8,705 stems/ha), intermediate in roadside plantings (1,274 stems/ha), and lowest in conservation plantings (212 stems/ha). Most milkweeds were common milkweeds Asclepias syriaca, which were more abundant in roadside than conservation plantings. Remnants contained the most milkweed species. Total milkweed and common milkweed abundance were both predicted by higher soil pH, a more linear site shape, and lower soil bulk density across restorations. Our results indicate that common milkweed is maintained by disturbance, and establishes readily in rural roadside habitat. Remnants are important as reservoirs for multiple milkweed species and should be protected.     

Using soil and litter arthropods to assess the state of rainforest restoration

Summary The present study investigated recolonization patterns of selected soil and litter arthropods following replanting of pasture with rainforest species in the Mary River catchment of eastern subtropical Australia. While extensive research has been conducted in rehabilitated mined sites in Australian dry sclerophyll forests, very little attention has been paid to rainforest restoration on previously pastoral land. We examined the utility of soil and litter arthropod groups for monitoring the progress of restoration, and the relationship between arthropod assemblage patterns and environmental factors potentially under the control of those doing the replanting. Leaf litter was extracted from 20 sites: five remnant rainforest, five pasture, and 10 sites that had been revegetated (from 1 to 12 years previously) with a diversity of indigenous species. Ants (identified to genus), centipedes, millipedes, isopods, amphipods and mites were enumerated and their assemblages described with multi- and univariate methods. Ant genera alone proved unable to distinguish pasture from rainforest, and mites (identified only to oribatid or non-oribatid) proved of limited use because these two groups were present in all samples in extremely high numbers that overwhelmed the contributions of other arthropod groups. However, a coarse taxonomic approach using five arthropod groups (ants, centipedes, millipedes, isopods, amphipods) clearly discriminated between pasture and rainforest, and also arranged the revegetated sites between these two extremes. Simple frequency scores based on the presence/absence of these arthropod groups in each of three replicate subplots were sufficient to achieve this separation of site types. Habitats created by close planting of trees and mulching may accelerate invertebrate colonization and, thus, promote the rapid establishment of processes and functions characteristic of developing rainforests.     

Soil reconstruction after mining fails to restore soil function in an Australian arid woodland

The biogeochemical properties of soils drive ecosystem function and vegetation dynamics, and hence soil restoration after mining should aim to reinstate the soil properties and hydrological dynamics of remnant ecosystems. The aim of this study is to assess soil structure in two vegetation types in an arid ecosystem, and to understand how these soil properties compare to a reconstructed soil profile after mining. In an arid ecosystem in southeast Australia, soil samples were collected at five depths (to 105 cm) from remnant woodland and shrubland sites, and sites either disturbed or totally reconstructed after mining. We assessed soil physico‐chemical properties and microbial activity. Soils in the remnant arid ecosystem had coarse‐textured topsoils that overlay clay horizons, which allows water to infiltrate and avoid evaporation, but also slows drainage to deeper horizons. Conversely, reconstructed soils had high sand content at subsoil horizons and high bulk density and compaction at surface layers (0–20 cm). Reconstructed soils had topsoils with higher pH and electrical conductivity. The reconstructed soils did not show increased microbial activity with time since restoration. Overall, the reconstructed soil horizons were not organized in a way that allowed rainfall infiltration and water storage, as is imperative to arid‐zone ecosystem function. Future restoration efforts in arid ecosystems should focus on increasing sand content of soils near the surface, to reduce evaporative water loss and improve soil quality and plant health.     

Hydrological prerequisites for optimum habitats of riparian Salix communities – identifying suitable reforestation sites

Question: What are the hydrological requirements for the successful reforestation of riparian Salix communities? Do differences in site conditions between various life stages of woody vegetation types need to be considered? Do interactions between hydrological factors influence distribution patterns? Location: Mid‐reaches of the Elbe River, Germany. Methods: Young and old life stages of two different riparian Salix communities were surveyed in 1067 plots of 400 m² to determine hydrological growth conditions using habitat distribution models. Models were extrapolated in a Geographic Information System to quantify the extent of potential stands available for reforestation measures. Results: Average water level and water level fluctuations were related to different vegetation types as well as to the age classes of the vegetation types. Differences in hydrological niches of young and old vegetation of the two vegetation types (tree community versus shrub community) could be identified. Moreover, the shrub vegetation was influenced by the interaction of average water level and fluctuations. Comparison of the distribution of current vegetation and suitable habitat revealed that considerable areas of the floodplain were suitable for the reforestation of Salix woodland communities. Conclusions: Hydrological variables explain the distribution patterns of riparian Salix communities in the active floodplain when different life stages, vegetation types and interaction of variables are included in the analyses. This information can be used to recommend suitable sites for Salix plantings in riparian landscapes.     

Effects of a Severe Frost on Riparian Rainforest Restoration in the Australian Wet Tropics: Foliage Retention by Species and the Role of Forest Shelter

Restoration of ecological communities that can withstand future climate and land use changes requires information on species responses to various natural disturbances. Frost is an important disturbance that regulates plant species distributions, and although rare in tropical rainforest, it can occur in upland areas, especially where deforestation has occurred. We report the impacts of a severe frost that occurred in June and July 2007 on the Atherton Tablelands, Queensland, Australia and caused extensive damage to riparian restoration plots of upland rainforest species. We estimated proportion foliage retention to (1) compare impacts across 45 species; (2) examine the influence of plant height on frost effects; and (3) determine if plantings under shelterbelts of mature trees received less damage. Species exhibited different levels of foliage retention. Species that were particularly frost resistant included those from riparian habitats and a conifer. Some heavily impacted species are deciduous and may survive frost by shedding leaves; this warrants further investigation. Plant canopy height above ground level was only weakly correlated to foliage retention. Sheltered plants were much less damaged than unsheltered conspecifics, suggesting a useful way to mitigate frost impacts. These principles should help guide the development of resilient ecological communities in frost‐prone areas.     

Potential of ants and beetles as indicators of rainforest restoration: characterising pasture and rainforest remnants as reference habitats

Assessment of habitat restoration requires baseline information on the communities present in both converted and intact forms of the focal ecosystem to enable comparisons with restored sites. Ants and beetles are commonly used in ecological monitoring programmes, as they display assemblage‐level responses to habitat change and can be a more direct measure of the recommencement of some ecosystem functions than the presence of more obvious biota such as plants. However, as these taxa differ substantially in ecological traits, their response patterns and utility as potential bioindicators may vary. Using pitfall traps, we compared assemblages of ant and beetle species between two reference habitats, pasture and remnant rainforest in subtropical eastern Australia. The assemblage composition of both groups differed significantly between rainforest and pasture but only beetles showed accompanying differences in species richness and abundance, which were both significantly lower in pasture. We identified ant and beetle species characteristic of either pasture or rainforest remnants, which may be used as bioindicators in future monitoring programmes. These species, however, displayed patchy distributions, suggesting that the use of individual species as bioindicators is likely to be unreliable. These findings support the use of ‘composite habitat indices’, which combine information from sets of indicator species. Given that patterns of change in species composition were similar between ants and beetles, either is an appropriate focal taxon for future monitoring programmes. Beetles, however, displayed some limitations as no species were indicative of the disturbed pasture habitat. Ants and beetles are likely to respond in different ways to different aspects of habitat change; thus, using both together could strengthen assessments of rainforest degradation or recovery.     

三峡库区苔藓生物结皮对土壤水分入渗的影响

在三峡库区王家桥小流域选取以苔藓为优势种的生物结皮样地,以附近无结皮发育的裸地为对照,设计5个盖度水平(1%～20%、20%～40%、40%～60%、60%～80%和80%～100%),采用环刀法测定土壤入渗过程,研究生物结皮盖度对入渗过程的影响。结果表明: 与裸地相比,生物结皮发育可显著提高表层土壤粘结力、孔隙度、黏粒含量、水稳性团聚体和有机碳含量,显著降低土壤容重和砂粒含量。生物结皮促进了土壤水分入渗,初始入渗率、稳定入渗率、平均入渗率和累积入渗量可达裸地的2.0倍及以上,土壤入渗性能随结皮盖度的增大呈先增加后减小的变化规律,在40%～60%盖度下最大。通径分析显示,土壤初始入渗率主要受结皮盖度、土壤容重和有机碳含量的影响,稳定入渗率主要受结皮盖度和土壤容重的影响。Horton模型对三峡库区生物结皮覆盖土壤的水分入渗过程拟合效果最佳。