Recovery Of Biodiversity Research Articles

Early Triassic vertebrate burrows from the Katberg Formation of the south-western Karoo Basin, South Africa

Bordy, E.M., Sztanó, O., Rubidge, B.S. & Bumby, A. 2010: Early Triassic vertebrate burrows from the Katberg Formation of the south-western Karoo Basin, South Africa. Lethaia, Vol. 44, pp. 33–45. Very large (∼30–35 cm), uniform diameter cylindrical burrows were found at two localities, ∼100–110 m above Permo-Triassic boundary in the fluvial Katberg Formation (main Karoo Basin, South Africa). Analysis of their morphology and stratigraphical distribution allows us to improve both the understanding of the ethology of burrowing, and also the reconstruction of the earliest Triassic ecosystems. These burrows have a single opening that leads, via a large, uniform diameter, semi-horizontal tunnel, to a rounded terminus. These 3-m-long structures descend at angles of ∼30° to a maximum of 1.5 m depth. They are devoid of chambers, branching, cross-cutting, coiling or spiralling. Filled with coarse sediments, some have a <5-mm clay lining, and most have subtle indentations and various scratch marks. These burrows were possibly excavated as resting, hiding or aestivating shelters, and are tentatively attributed to dicynodonts (i.e. Lystrosaurus murrayi and L. declivis). Data suggest that burrowing was widespread after the P/Tr boundary event, when in this part of Gondwana, dryland fluvial systems had large fluctuations in flow with extended low-flow periods or drought punctuated by high-discharge periods. We hypothesize that these constructed refuges played a role in the biodiversity recovery and maintenance in the Early Triassic (Induan) ecosystem. □Early Triassic, Karoo Basin, Katberg Formation, South Africa, Tetrapod Burrows.

High levels of green‐tree retention are required to preserve ground beetle biodiversity in boreal mixedwood forests

Recovery of biodiversity and other ecosystem functions to pre-disturbance levels is a central goal of natural disturbance-based approaches to ecosystem management. In boreal mixedwood forests, green-tree retention has been proposed as an alternative approach to traditional clearcutting that may minimize initial displacement of species assemblages and speed recovery of the biota. Here we evaluated the effectiveness of six levels of dispersed greentree retention for conservation of ground beetle biodiversity in four boreal mixedwood cover types that span a gradient of stand development following wildfire. Each cover type X treatment combination was replicated three times in an operational scale experiment using 10-ha compartments. Ground beetle assemblages (59 species and 45 419 individuals) responded to increasing levels of dispersed, green-tree retention, but even relatively high levels of retention (up to 50% retention) did not retain species assemblages characteristic of uncut forest stands. This latter effect was most pronounced in compartments in later successional stages; i.e., those with developing conifer understories, or mixed and/or conifer-dominated overstories. Beetle assemblages in high levels of retention (50-75%) were statistically similar across all cover types, although we detected modest differences among the 5-year recovery of assemblages, based on initial cover type differences. Thus, recovery to initial conditions likely will be slower in mixed and conifer stands than in deciduous stands. We suggest that recovery of beetle assemblages is strongly linked to stand reinitiation through deciduous "suckering" post-harvest. Increasing levels of harvest appear to homogenize carabid assemblages across the four dominant cover types, and thus higher levels of retention (>50%) will be required to preserve assemblages of later successional stages. Regional renewal of assemblages, however, will require landscape-level planning.

Recovery of benthic macroinvertebrate and adult dragonfly assemblages in response to large scale removal of riparian invasive alien trees

Invasive alien organisms can impact adversely on indigenous biodiversity, while riparian invasive alien trees (IATs), through shading of the habitat, can be a key threat to stream invertebrates. We ask here whether stream fauna can recover when the key threat of riparian IATs is removed. Specifically, we address whether IAT invasion, and subsequent IAT removal, changes benthic macroinvertebrate and adult dragonfly assemblages, for the worse or for the better respectively. Natural riparian zones were controls. There were statistically significant differences between stream reaches with natural, IAT-infested and IAT-cleared riparian vegetation types, based on several metrics: immature macroinvertebrate taxon richness, average score per macroinvertebrate taxon (ASPT), a macroinvertebrate subset (Ephemeroptera, Plecoptera, Trichoptera and Odonata larvae; EPTO), and adult dragonfly species richness. Reaches with natural vegetation, or cleared of IATs, supported greater relative diversity of macroinvertebrates than reaches shaded by dense IATs. Greatest macroinvertebrate ASPT and EPTO were in reaches bordered by natural vegetation and those bordered by vegetation cleared of IATs, and the lowest where the riparian corridor was IATs. Highest number of adult dragonflies species was along streams cleared of dense IATs. Overall, results showed that removal of a highly invasive, dense canopy of alien trees enables recovery of aquatic biodiversity. As benthic macroinvertebrate scores and adult dragonfly species richness are correlated and additive, their combined use is recommended for river condition assessments.

Biodiversity Differences between Managed and Unmanaged Forests: Meta‐Analysis of Species Richness in Europe

Past and present pressures on forest resources have led to a drastic decrease in the surface area of unmanaged forests in Europe. Changes in forest structure, composition, and dynamics inevitably lead to changes in the biodiversity of forest-dwelling species. The possible biodiversity gains and losses due to forest management (i.e., anthropogenic pressures related to direct forest resource use), however, have never been assessed at a pan-European scale. We used meta-analysis to review 49 published papers containing 120 individual comparisons of species richness between unmanaged and managed forests throughout Europe. We explored the response of different taxonomic groups and the variability of their response with respect to time since abandonment and intensity of forest management. Species richness was slightly higher in unmanaged than in managed forests. Species dependent on forest cover continuity, deadwood, and large trees (bryophytes, lichens, fungi, saproxylic beetles) and carabids were negatively affected by forest management. In contrast, vascular plant species were favored. The response for birds was heterogeneous and probably depended more on factors such as landscape patterns. The global difference in species richness between unmanaged and managed forests increased with time since abandonment and indicated a gradual recovery of biodiversity. Clearcut forests in which the composition of tree species changed had the strongest effect on species richness, but the effects of different types of management on taxa could not be assessed in a robust way because of low numbers of replications in the management-intensity classes. Our results show that some taxa are more affected by forestry than others, but there is a need for research into poorly studied species groups in Europe and in particular locations. Our meta-analysis supports the need for a coordinated European research network to study and monitor the biodiversity of different taxa in managed and unmanaged forests.

Site requirements of the endangered rosewood Dalbergiaoliveri in a tropical deciduous forest in northern Thailand

Planting native trees may complement and accelerate natural regeneration and support recovery of biodiversity in degraded forests. Before planting trees, however, there is a need for species-specific site selection criteria. This study investigates the site requirements of a valuable but endangered rosewood species, Dalbergia oliveri, with the purpose of restoring degraded deciduous forest in northern Thailand. The study was conducted in the Ban Pong Forest near Chiang Mai in northern Thailand. We determined site characteristics of plant communities where D. oliveri occurred with indirect gradient analysis and used the importance value index (IVI) to determine the social position of D. oliveri compared to the dominant tree species. The forest was dominated by fire-tolerant dipterocarps. D. oliveri was a co-dominant component in two communities, mixed deciduous forest and the mesic phase of the deciduous dipterocarp forest, on deeper soils of the foothills and on less sun-exposed slopes. In dry deciduous dipterocarp forest, on the driest or steepest slopes with shallow soil, D. oliveri was an emergent or canopy tree with exceptionally well-developed crowns compared to the much smaller, but numerous dipterocarps. In conclusion, D. oliveri existed across a range of environmental limiting factors within various forest facies of deciduous forest in northern Thailand, and therefore, is likely a suitable candidate for restoration of degraded forests. On highly degraded sites the species can assist in restoring a more mesic forest microclimate. Planting or sowing D. oliveri in degraded forests may help to reduce pressure on the remaining wild rosewood populations, and serves in both conservation of biodiversity and economic production.

Factors affecting site occupancy by woodland bird species of conservation concern

Significant biodiversity loss is characteristic of agricultural landscapes worldwide. Biodiversity recovery efforts in such landscapes can be hamstrung by a paucity of information on factors affecting species’ distributions, particularly for threatened and/or declining species. The temperate woodlands of south-eastern Australia have been extensively modified for agriculture and numerous bird taxa are declining. We have explicitly identified habitat and landscape attributes of woodland remnants affecting site occupancy by 13 woodland bird species of conservation concern. Using case-control data and linear logistic regression, we found that site occupancy for each species was related to both habitat and landscape variables. Habitat variables of particular importance included those in the ground layer (an abundance of leaf litter, an intact surface crust of mosses and lichens and a scarcity of annual grasses) and overstorey (a scarcity of eucalypt dieback and an abundance of mistletoe). Landscape variables strongly affecting site occupancy included the number of paddock trees and the area of native grass within 500 m of a site. Many of our study species were found most often in regrowth remnants. Our findings indicate a gap between current conservation practices and the actual habitat requirements of woodland bird species of conservation concern. Successful management will require protection and/or rehabilitation of the ground layer and overstorey of woodland remnants and sympathetic management of the surrounding landscape. It also will require managers to go beyond current practices of conserving old growth remnants and establishing replantings to maintaining and creating stands of woodland regrowth.

Chicago Wilderness Green Infrastructure Vision: Challenges and Opportunities for the Built Environment

The Chicago Wilderness Biodiversity Recovery Plan has won state and national awards for its farsighted approach to regional biodiversity protection. Inspired by Daniel Burnham's Plan of Chicago, the Green Infrastructure Vision takes a step beyond the Recovery Plan by mapping an on-the-ground vision of what could and should be protected in the regional landscape. This Green Infrastructure Vision (GIV) identifies 1.8 million acres of macro-scale resource protection areas that span a region that includes southeastern Wisconsin, northeastern Illinois, and northwestern Indiana. This ambitious vision will require an integrated array of land protection techniques, including acquisition, conservation easements, greenway connections, restoration, and conservation development. Its implementation is being pursued at a range of spatial scales, including regional comprehensive plans, county and municipal plans and ordinances, and at the neighborhood and individual development level. The Vision presents unique opportunities and challenges for both the development community and local governments as progressive new approaches to sustainable land use and conservation development are considered and implemented.

The river Rhine: a global highway for dispersal of aquatic invasive species

The river Rhine is heavily influenced by human activities and suffers from a series of environmental constraints which hamper a complete recovery of biodiversity. These constraints comprise intensive navigation and habitat modification by hydraulic engineering. Improving water quality while these constraints remain in place has led to increased colonization by aquatic invasive species. This ten- dency has been accelerated by the construction of canals connecting river basins. Over the last two centuries, the total surface area of river catchments connected to the river Rhine via inland waterways has been increased by a factor 21.6. Six principal invasion corridors for aquatic species to the river Rhine are discerned. The extensive network of inland waterways has allowed macroinvertebrate species from different bio-geographical regions to mix, changing communities, affecting the food webs and forming new constraints on the recovery of the native biodiversity. From the eighteenth century onward, in the freshwater sections of the river Rhine, a total of 45 non-indigenous macroinvertebrate species have been recorded. The average number of invasions per decade shows a sharp increase from\1 to 13 species. Currently, the contribution of non-indigenous species to the total species richness of macroinvertebrates in the river Rhine is 11.3%. The Delta Rhine and Upper Rhine exhibit higher numbers of non-indigenous species than other river sections, because the sea ports in the Delta Rhine and the Main-Danube canal function as invasion gateways. Important donor areas are the Ponto-Caspian area and North America (44.4 and 26.7% of the non-indigenous macroinvertebrate species, respectively). Transport via shipping and

Integrated “plume winter” scenario for the double-phased extinction during the Paleozoic–Mesozoic transition: The G-LB and P-TB events from a Panthalassan perspective

The event across the Paleozoic–Mesozoic transition involved the greatest mass extinction in history together with other unique geologic phenomena of global context, such as the onset of Pangean rifting and the development of superanoxia. The detailed stratigraphic analyses on the Permo-Triassic sedimentary rocks documented a two-stepped nature both of the extinction and relevant global environmental changes at the Guadalupian–Lopingian (Middle and Upper Permian) boundary (G-LB, ca. 260 Ma) and at the Permo-Triassic boundary (P-TB, ca. 252 Ma), suggesting two independent triggers for the global catastrophe. Despite the entire loss of the Permian–Triassic ocean floors by successive subduction, some fragments of mid-oceanic rocks were accreted to and preserved along active continental margins. These provide particularly important dataset for deciphering the Permo-Triassic paleo-environments of the extensive superocean Panthalassa that occupied nearly two thirds of the Earth’s surface. The accreted deep-sea pelagic cherts recorded the double-phased remarkable faunal reorganization in radiolarians (major marine plankton in the Paleozoic) both across the G-LB and the P-TB, and the prolonged deep-sea anoxia (superanoxia) from the Late Permian to early Middle Triassic with a peak around the P-TB. In contrast, the accreted mid-oceanic paleo-atoll carbonates deposited on seamounts recorded clear double-phased changes of fusuline (representative Late Paleozoic shallow marine benthos) diversity and of negative shift of stable carbon isotope ratio at the G-LB and the P-TB, in addition to the Paleozoic minimum in 87Sr/ 86Sr isotope ratio in the Capitanian (Late Guadalupian) and the paleomagnetic Illawarra Reversal in the late Guadalupian. These bio-, chemo-, and magneto-stratigraphical signatures are concordant with those reported from the coeval shallow marine shelf sequences around Pangea. The mid-oceanic, deep- and shallow-water Permian records indicate that significant changes have appeared twice in the second half of the Permian in a global extent. It is emphasized here that everything geologically unusual started in the Late Guadalupian; i.e., (1) the first mass extinction, (2) onset of the superanoxia, (3) sea-level drop down to the Phanerozoic minimum, (4) onset of volatile fluctuation in carbon isotope ratio, 5) 87Sr/ 86Sr ratio of the Paleozoic minimum, (6) extensive felsic alkaline volcanism, and (7) Illawarra Reversal. The felsic alkaline volcanism and the concurrent formation of several large igneous provinces (LIPs) in the eastern Pangea suggest that the Permian biosphere was involved in severe volcanic hazards twice at the G-LB and the P-TB. This episodic magmatism was likely related to the activity of a mantle superplume that initially rifted Pangea. The supercontinent-dividing superplume branched into several secondary plumes in the mantle transition zone (410–660 km deep) beneath Pangea. These secondary plumes induced the decompressional melting of mantle peridotite and pre-existing Pangean crust to form several LIPs that likely caused a “plume winter” with global cooling by dust/aerosol screens in the stratosphere, gas poisoning, acid rain damage to surface vegetation etc. After the main eruption of plume-derived flood basalt, global warming (plume summer) took over cooling, delayed the recovery of biodiversity, and intensified the ocean stratification. It was repeated twice at the G-LB and P-TB. A unique geomagnetic episode called the Illawarra Reversal around the Wordian–Capitanian boundary (ca. 265 Ma) recorded the appearance of a large instability in the geomagnetic dipole in the Earth’s outer core. This rapid change was triggered likely by the episodic fall-down of a cold megalith (subducted oceanic slabs) from the upper mantle to the D″ layer above the 2900 km-deep core-mantle boundary, in tight association with the launching of a mantle superplume. The initial changes in the surface environment in the Capitanian, i.e., the Kamura cooling event and the first biodiversity decline, were probably led by the weakened geomagnetic intensity due to unstable dipole of geodynamo. Under the low geomagnetic intensity, the flux of galactic cosmic radiation increased to cause extensive cloud coverage over the planet. The resultant high albedo likely drove the Kamura cooling event that also triggered the unusually high productivity in the superocean and also the expansion of O 2 minimum zone to start the superanoxia. The “plume winter” scenario is integrated here to explain the “triple-double” during the Paleozoic–Mesozoic transition interval, i.e., double-phased cause, process, and consequence of the greatest global catastrophe in the Phanerozoic, in terms of mantle superplume activity that involved the whole Earth from the core to the surface biosphere.

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

AbstractThere 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.

Invasive aliens on tropical East Asian islands

Tropical East Asia (TEA) has numerous islands, both continental and oceanic. This study uses information on invasive aliens in terrestrial habitats on these islands to test the generality of the continental-oceanic contrast in invasibility, assess the conservation impacts of invasive species, and suggest ways to mitigate these. The continental islands of Hong Kong and Singapore are worst-case scenarios for continental invasibility and alien species often dominate in chronically disturbed sites, but very few have successfully invaded closed forests, with the exception of birds in Hong Kong. On other, less densely populated, continental islands, closed-canopy forests appear to resist invasions by all taxa, with few known exceptions. Forests on oceanic islands isolated by 1000 km from the nearest continent, have a native biota of largely tropical East Asian origin and are suffering from alien forest invasions across the taxonomic spectrum. These patterns of invasibility are consistent with the idea that alien invasion is facilitated by the absence of native species in the same functional group. Alien invasives are not yet a major conservation problem in TEA, except on remote islands, but their dominance on disturbed sites may slow or prevent recovery of native biodiversity. Strict quarantine is impractical in TEA, although some major introduction routes could be blocked. Management efforts should focus on early recognition and immediate control of potential problem species.

The effect of planted tree species on the development of herbaceous vegetation in a reclaimed opencast

The establishment of plantations is the most common method of opencast reclamation, but few studies have addressed the influence of planted trees on the recovery of biodiversity in new forest sites. The goal of this study was to determine whether the formation of herbaceous vegetation was dependent on the tree species planted on the spoil of a reclaimed oil shale opencast in northeastern Estonia. From 2002 to 2005, the vegetation in eight different site types (distinguished according to the age and composition of tree layer) was surveyed. The results confirmed that the development of herbaceous vegetation was controlled by the dominant species of tree layer. The highest number of herbaceous species was recorded in naturally developed mixed stands. As compared with other site types, the herb layers of the pioneer stage (the vegetation in recently reclaimed sites) and alder stands were the most different. In the terms of the competitive, stress-tolerant, and ruderal strategy types, alder (Alnus spp.) stands tended to enhance the growth of competitors, whereas stress-tolerant species were more abundant in pine stands. Herbaceous vegetation remained sparse in coniferous stands, whereas broad-leaved trees tended to improve the performance of herbaceous species. Our results concur with the suggestions that planting with different tree species is one prerequisite for the development of diverse herb layer.

Producing Framework Tree Species for Restoring Forest Ecosystems in Northern Thailand

Since 1994, the Forest Restoration Research Unit of Chiang Mai University’s Biology Department (FORRU-CMU) has been developing methods to restore forest ecosystems to deforested sites within protected areas, for biodiversity conservation and environmental protection in northern Thailand. With support from WWF Greater Mekong Thailand Country Programme and corporate sponsor King Power Duty Free, the unit is working with Hmong hill tribe villagers from Baan Mae Sa Mai, in Doi Suthep-Pui National Park, to expand a demonstration site for the “framework species method” of forest restoration. The technique entails planting 20 to 30 indigenous forest tree species, capable of rapidly shading out weeds and attracting seed-dispersing animals from nearby forest remnants. This results in rapid increase in tree species richness, progressing towards the species composition of the original forest, as well as overall biodiversity recovery. FORRU-CMU operates a research tree nursery, where innovative tree propagation techniques are developed, and a community-based nursery and education centre, where the practicability of those techniques is tested by local villagers. The nurseries and the demonstration field trials have become a popular training facility where visiting foresters and conservationists, both from Thailand and neighbouring countries, can learn effective forest restoration methods. FORRU-CMU provides a model for formulating a strategy to apply the framework species method to restore larger degraded sites within Thailand’s protected areas system.

Recovery of species diversity and composition of braconid parasitic wasps after reforestation of degraded grasslands in lowland East Kalimantan

Human-induced disturbances and wildfires can transform areas of tropical rainforest into Imperata-dominated grassland, but it may be possible that recovery of biodiversity is facilitated by reforestation with fast-growing trees. We compared the assemblages of braconid wasps as parasitoids of taxonomically diverse groups of insects among Imperata grasslands, young and mature plantations of Acacia mangium, young secondary forests after wildfires, and old secondary forests in the lowland of East Kalimantan. The abundance and species richness of braconids, which had declined in Imperata grasslands, somewhat increased in Acacia plantations, and also the species composition of braconids in Acacia plantations was transitional between Imperata grasslands and old secondary forests. Parasitoids of detritivores and wood borers increased markedly after plantation, while those of herbivores showed a distinct turnover of species all over the range from grasslands to old secondary forests. The plantation of A. mangium had most likely facilitated the recovery of the diversity of host forest and their parasitoids, but the recovery was just at the rudimentary stage even in mature plantations. Monitoring of parasitic wasps would be useful to test the continuous recovery of forest biodiversity in plantation stands.

Setting the Tempo in Land Remediation: Short-Term and Long-Term Patterns in Biodiversity Recovery

Land to be remediated, such as those affected by heavy metals or organic pollutants, can be remediated using biological approaches. These include, quarries and strip mines, or land impacted by oil pollution or other organic pollutants. Phytoremediation is usually a key component of bioremediation. However, without restoring soil organic matter, the soil biodiversity takes decades to recover. The soil organisms are a key component of soil function, and support plant growth. In addition, the soil microbiology is essential both for bioremediation and supporting phytoremediation. Using inexpensive sources of quality organic matter, it should be possible to accelerate recovery of ecosystem health and biodiversity. One potential source of untapped organic matter is municipal solid waste as a composted amendment. The organic matter amendment promotes soil structure and the creation of adequate habitat and substrate for the soil decomposition food web. Long-term chronosequence studies indicate that soil food webs tend to make a transition after about 20 years to a stable community structure. This approach could be used to gain carbon credits by restoring degraded or polluted soils.

Location relative to a retention patch affects the ECM fungal community more than patch size in the first season after timber harvesting on Vancouver Island, British Columbia

Silviculture systems that include retention of green trees are becoming more common in North America. The goals of green tree retention are to maintain forest structural diversity, preserve species associated with mature forests and to support faster post-harvest recovery of biodiversity. We studied the proportion of living roots and ectomycorrhizal (ECM) fungal communities in, and adjacent to, aggregated retention patches of coastal western hemlock forest on Vancouver Island, 4–6 months after harvest. Our objectives were to determine, for the window of time during which replanting typically occurs, (i) whether aggregated patches of green trees had retained ECM fungal communities similar to uncut forest and whether this depended on patch size; (ii) how far the influence of the patch extended into the harvested area, and whether this depended on patch size. These factors will influence the effectiveness of the aggregated patches as inoculum sources for seedlings planted in adjacent harvested areas. Soil samples were collected at the center and edge of 16 patches: four replicates each of 5, 10, 20, and 40 m diameter patches, as well as at 10 and 20 m into the harvested area around each patch. A control-forested area was also sampled. The state of the stele was used to designate 25 lateral roots from each sample as live or dead. One hundred active mycorrhizas per sample were then examined and described morphologically. The internal transcribed spacer region of the fungal rDNA was amplified and sequenced from representative tips of each morphotype. ECM communities were indistinguishable between uncut forest and the aggregated retention patches. This was true for patches as small as 5 m in diameter, with no significant overall effect of patch size on ECM fungal species richness, Shannon Diversity Index, or the proportion of live root segments. Sampling location, however, significantly affected all these variables, with the influence of the patch disappearing by 10 m into the harvested area. The only indication of a patch size effect was that ECM species richness at the edges of the 5 m plots was slightly lower (P < 0.1) than the edges of larger patch sizes. Based on these results, we recommend that patch sizes be at least 10 m in diameter for coastal western hemlock forests. Since the edge:area ratio of smaller patches is higher, more small patches of at least 10 m diameter would be more effective than a few large patches in supplying ECM inoculum to adjacent harvested areas during the first year after harvest.

Application of Assisted Natural Regeneration to Restore Degraded Tropical Forestlands

Abstract Assisted natural regeneration (ANR) is a simple, low‐cost forest restoration method that can effectively convert deforested lands of degraded vegetation to more productive forests. The method aims to accelerate, rather than replace, natural successional processes by removing or reducing barriers to natural forest regeneration such as soil degradation, competition with weedy species, and recurring disturbances (e.g., fire, grazing, and wood harvesting). Compared to conventional reforestation methods involving planting of tree seedlings, ANR offers significant cost advantages because it reduces or eliminates the costs associated with propagating, raising, and planting seedlings. It is most effectively utilized at the landscape level in restoring the protective functions of forests such as watershed protection and soil conservation. ANR techniques are flexible and allow for the integration of various values such as timber production, biodiversity recovery, and cultivation of crops, fruit trees, and non‐timber forest products in the restored forest. This paper describes the steps of applying ANR and conditions under which it will be most effective. It also discusses ANR’s comparative advantages as well as some of its constraints.

Restoration of Prairie Community Structure and Ecosystem Function in an Abandoned Hayfield: A Sowing Experiment

AbstractUsing a multispecies seed sowing experiment, we investigated the roles of seed and microsite limitation in constraining the restoration of native prairie diversity and ecosystem function in an abandoned upland hayfield in northeastern Kansas. Seeds of 32 native and naturalized plant species from the regional pool were sown into undisturbed and experimentally disturbed field plots. After six growing seasons, experimental sowing led to major shifts in species and functional group composition, increases in native species abundance and floristic quality, declines in abundance of non‐native species, and increases in plant diversity. These changes in community structure led to significant changes at the ecosystem level including increases in light capture, peak biomass, primary production, litter biomass, root biomass, and C storage in roots. Our findings reveal the importance of seed limitations in constraining the natural recovery of prairie vegetation, biodiversity, and ecosystem functioning in this grassland and confirm broadcast sowing as a useful tool for the restoration of upland hayfield sites.

Planning for broad-based environmental protection: A look back at the Chicago Wilderness Biodiversity Recovery Plan

In 1994 a collaboration of environmental interests formed in the Chicago region, U.S.A. Composed of representatives of environmental organizations, government agencies, citizen and neighborhood groups, private interests, and university representatives, the consortium provides a forum for communication, advocacy, policy, and sharing ideas and knowledge about biodiversity issues and the various activities of each organization. The specific mission of the Chicago Wilderness Consortium is to protect, restore, and manage natural lands, plants, and animals in the Chicago region. Shortly after forming the Chicago Wilderness Consortium, the idea of creating a region-wide biodiversity recovery plan emerged, in order to provide a blueprint for how the consortium would accomplish its mission. Within a few years, the group began work on the Chicago Wilderness Biodiversity Recovery Plan, and it is now among the first regional biodiversity plans in the United States. While using collaborative planning processes to solve environmental problems is not unique, the Biodiversity Recovery Plan and the process through which it was created were innovative in the U.S. for having a broad and ambitious scope, extensive use of some kinds of data and analysis (particularly on natural communities), the large number of participants in the planning process (over 200), and the dispersed organizational structure in which the consortium operates. Another innovation was adoption of the plan by three regional planning commissions in three different states. The Chicago Wilderness Biodiversity Recovery Plan was one of the first major departures from traditional (single-medium based) environmental planning by a region in the United States. These innovations warrant research and reflection, 8 years after completion of the plan, and are the focus of this article.

Physicochemical changes in sediments at Orplands Farm, Essex, UK following 8 years of managed realignment

Managed realignment (MR) is a ‘soft’ engineering technique that involves the deliberate landwards retreat of the existing line of coastal defence and subsequent tidal inundation of land. Managed realignment has been established worldwide for over 30 years and its goals may include habitat restoration, recovery of biodiversity and sustainable coastal defence. In southeast England in particular, an increasing number of MR sites (20–110 ha) have been commissioned in the last decade in response to increasing coastal habitat loss and sea-level rise. Following initial sea wall breaching and site flooding, monitoring of these sites is usually carried out for a period of 5 years and during this time changes in ecosystem structure can be easily observed. However, there is a poor understanding of the long-term effects of flooding on soil physicochemical parameters including sediment geochemistry and geochemical cycling, nutrient fluxes and soil maturation processes. Such physical and chemical changes may continue to take place over time-scales exceeding 5 years and therefore current monitoring practices may not be sufficient. This paper examines the changes in the physicochemical parameters of sediments in vertical core sections at the Orplands Farm MR site, Blackwater Estuary, Essex, 8 years after its flooding in 1995. Post-breach sediment accumulation rates at the site have been determined and a multi-proxy approach has been used to identify a pre-breach land surface. Soil development and the vertical distribution of saltmarsh plants following breaching have also been examined. The species saturation index approach has been used to provide an indication of the success of MR at this site. The pre-breach land surface was identified at 4–6 cm depth indicating a sediment accumulation rate ca. 0.75 cm a −1 since the site was breached in 1995. This sedimentation rate exceeds the regional sea-level rise of 0.1–0.3 cm a −1 and hence marsh development at the site is expected to continue in the short term. The examination of physicochemical parameters with depth indicates that the pre-breach land surface forms a barrier that may inhibit vertical tidal flushing, nutrient transfer and contaminant removal. The vegetation was mostly a pioneer and low-mid marsh assemblage typical of the area, although the species saturation index is low compared to other European sites and this may be attributed to a range of factors including poor drainage at the site and reduced seed availability.