Recruitment of three non-native invasive plants into a fragmented forest in southern Illinois

Plant invasions are a current threat to biodiversity conservation, second only to habitat loss and fragmentation. Density and heights of three invasive plants, Rosa multiflora, Lonicera japonica, and Elaeagnus umbellata, were examined between edges and adjacent interiors of forest sites in southern Illinois. Density (stems m⁻²) and heights (cm) of invasive plants were obtained in plots along transects at edge and interior sampling locations within forest sites. The effect of species, sampling location, and site shape index on invasive plant density was investigated, as well as differences in heights of invasive plants in edge vs. interior sampling locations.

Species, sampling location, and fragment shape index were significant factors influencing invasive plant density at study sites. Density for all three species ranged from 0 to 18 stems m⁻². All three species invaded interiors of sites, however, R. multiflora and L. japonica had significantly greater densities in edge as opposed to interior transects. These two species also had significant differences in density among site shape indices. Density of E. umbellata was not significantly different between edge and interior sampling locations or among site shape indices. Mean heights of all three invasive plants were higher in edge transects, however, this relationship was only significant for L. japonica.

These findings suggest that (1) preservation of tracts of forest with less edge can minimize invasion by these three plants in this area. Interiors of forest sites can be protected from invasion by having less edge habitat for invasive species to enter and become established; and (2) E. umbellata, unlike the other two species, is established in both interior and edges of study sites. Therefore, E. umbellata may pose the most ecological damage because it is well established throughout sites, and should be given a high priority when implementing management and control efforts in southern Illinois forest ecosystems.     

Think globally,manage locally: The importance of steady-state forest features for a declining songbird

Changes in historical forest composition and structure may have cascading effects throughout the forest community. Perhaps nowhere is there a better example of current forests that carry a legacy from their past than in eastern North America. The Cerulean Warbler (Dendroica cerulea), a declining Neotropical migratory bird of high conservation concern, is one excellent example of a species that seems to be sensitive to both landscape configuration and subtle features of eastern forests of North America. We used the Cerulean Warbler as a model species to demonstrate how an appreciation of fine-scale structural attributes of forests may improve our ability to conserve late-successional forest species. To do this we evaluated the extent to which multiscale habitat features were associated with density, spatial distribution, and nesting success of Cerulean Warblers in 12 mature forest sites in southeast Ohio, 2004–2006. Results suggest that adjacency of regenerating clear-cuts did not influence density or nesting success of Cerulean Warblers in adjacent mature forest. Instead, variation in demographic parameters was best explained by local habitat features. Density and nesting success were positively associated with canopy openness, numbers of large-diameter trees, and number of grapevines—all of which are typical of heterogeneous steady-state phase forests. Thus, improved management for Cerulean Warblers may require creating features (e.g., large canopy gaps) that mimic old-growth forests. Although fragmentation and habitat loss remain important contributors to population declines of many mature forest species, our work provides evidence that subtle changes in forest structure, particularly to features associated with old forests, warrant additional attention from the conservation community.     

A functional analysis of streamside habitat use by southern Appalachian salamanders: Implications for riparian forest management

The appropriate management of streamside forests and use of riparian strips is poorly resolved for many systems because of a lack of understanding of the extent to which riparian forests function as environmental buffers for aquatic species versus core (essential) habitat for semi-aquatic and terrestrial species. We studied streamside forests in western North Carolina and eastern Tennessee, USA, to help delineate their functional value for plethodontid salamanders. We established 30 m × 40 m plots at 17 sites (823–1716 m in elevation) in unmanaged forests with closed canopies. Plots contained a portion of a seep or first-order stream along one edge and typically extended 36–38 m into the adjoining forest. We examined use of stream and streamside habitats based on captures during area-constrained searches of cover objects. We observed 6423 plethodontid salamanders belonging to 7 terrestrial-breeding and 12 aquatic-breeding species. Terrestrial-breeders (primarily Plethodon spp.) comprised 37% of terrestrial specimens and were more abundant at higher elevations. Aquatic-breeders (primarily Desmognathus spp.) increased their proportionate use of terrestrial habitat, but declined in overall abundance with elevation. Catches of aquatic-breeders were greatest within 8 m of aquatic habitats (49% of total terrestrial catch of aquatic-breeders), particularly at low elevation sites. The terrestrial zone provided core habitat for one terrestrial-breeder (D. wrighti) and six semi-aquatic species (Desmognathus spp., Gyrinophilus porphyriticus and Eurycea wilderae) that were broadly distributed throughout plots, and acted as an aquatic buffer for four highly aquatic species (Desmognathus spp.). The remaining species were terrestrial-breeders (Plethodon spp.) that were evenly distributed across plots, suggesting that riparian strips would function as important source populations for recolonization following timbering on adjoining land. Because of the vulnerability of plethodontid salamanders to edge effects, effective management of southern Appalachian streamside habitats may require the addition of a terrestrial buffer to protect terrestrial core habitat that immediately adjoins streams and seeps.     

Forest fragmentation and duration of forest tent caterpillar (Malacosoma disstria Hübner) outbreaks in northern hardwood forests

In northern forests dominated by aspen (Populus spp.), the duration of outbreaks of forest tent caterpillar (Malacosoma disstria Hübner) has been reported to increase with forest fragmentation. This relationship has not been tested in other forest types affected by this widespread native defoliator. From 2002 to 2007, a large-scale outbreak of this insect in the northeastern United States defoliated millions of hectares, with sugar maple (Acer saccharum Marsh.) the primary host. We used digital defoliation maps generated from aerial surveys and national land cover data to assess the effect of fragmentation on outbreak duration in areas of NY, MA, VT, and NH. We found that outbreak duration increased with forest cover and decreased with the forest edge, in opposition to the pattern previously reported for aspen-dominated forests in Canada. This pattern was significant from plot sizes ranging from 100 m to 1000 m in radius. The relationship between FTC and its natural enemies, which was postulated to underlie the effect of fragmentation on outbreaks in aspen forests, may be affected differently in northern hardwood forests, or other factors may be more important in determining outbreak duration in this forest type.     

Distribution patterns of acorns after primary dispersion in a fragmented oak forest and their consequences on predators and dispersers

Forest fragmentation affects seed production, but little is known about how seeds are distributed in fragmented forests after primary dispersion and how this affects their interactions with other organisms. This study addressed these issues in a fragmented oak forest of Quercus laeta where four habitat types were recognized: interior and edge of patches, deforested matrix around patches, and an abandoned field. Areas and distances to the abandoned field were measured for 40 patches, and acorns were sampled in all habitats. Only samples from the interior and edge of patches had acorns, which were classified as aborted, viable, and parasitized by insects or fungi. Acorns in all these classes were regressed against patch area and distance to the abandoned field. Field experiments were also conducted to determine whether acorn removal rates varied across habitats. Aborted acorns within patches were not related to area or distance, but they decreased with increasing values of both variables at patch edges. Within patches, viable acorns were positively related to increases in area and distance, while the converse occurred for insect-damaged acorns; fungal-infested acorns were not related to patch variables in this habitat. Complex interactions between area and distance explained how acorns in these classes were distributed across patch edges. Acorn removal was higher within patches and their edges when compared to human-disturbed habitats; both mice and birds were identified as potential acorn dispersers. These results suggest that forest fragmentation affects acorn-mediated processes and that this may influence the recovery of patch connectivity in the landscape.     

Understory succession in post-agricultural oak forests: Habitat fragmentation affects forest specialists and generalists differently

The herbaceous understory forms the richest stratum in temperate broadleaved forests in terms of plant diversity. Understanding the process of understory succession is thus of critical importance for the development of management guidelines for biodiversity restoration in post-agricultural plantation forests.We studied effects of stand age, forest fragmentation, and soil and canopy conditions on species richness and abundance of four species groups in the understory of post-arable oak plantations in southern Sweden: herbaceous forest specialists, habitat generalists and open-land species, and woody species.The group of forest specialists may approach the richness of continuously forested sites after 60-80 years in non-fragmented plantations, but many forest species were sensitive to habitat fragmentation. Open-land species richness decreased during succession, while the richness of woody species and of generalists remained stable, and was not affected by fragmentation. Abundance of generalists gradually decreased in non-fragmented plantations, probably due to competition from colonizing forest specialists. Soil pH in post-arable stands remained consistently higher than in continuously forested stands, which maintained differences in species composition. The development of a shrub layer seemed to imply a competitive advantage for forest specialists compared to generalist species.For successful recovery of a rich understory, we suggest that post-arable plantations should be established on loamy soils of intermediate to high pH proximate to older forest with source populations, and that a continuous overstory canopy cover of 70-80% is maintained by regular light thinnings and promotion of a shrub layer.     

Effects of even-aged timber harvest on stream salamanders: Support for the evacuation hypothesis

Habitats worldwide are increasingly threatened by degradation and conversion. Critical to the process of habitat loss is the organismal response, which can have effects on immediate conservation measures or future restoration. Among the most threatened and underappreciated habitats are headwater streams, which are small but abundant features of montane forests. These habitats comprise a significant proportion of the total stream length, can harbor remarkable biodiversity, and are critical for numerous ecosystem processes. One of the most abundant organisms in montane headwater ecosystems are salamanders, and therefore what happens to salamanders when the forest habitats surrounding headwater streams are altered? Three main hypotheses exist: (1) mortality hypothesis; (2) retreat hypothesis; and (3) evacuation hypothesis. To examine these hypotheses we evaluated the impacts of even-aged riparian timber harvest on stream-breeding salamanders. Riparian forests along headwater streams were logged, leaving riparian buffers of 0 m, 9 m, and 30 m. Responses to each riparian alteration were measured in terms of salamander terrestrial habitat use and growth in the riparian habitat, as well as changes in population density within headwater streams. Adult and juvenile salamander densities measured in headwater streams were significantly greater in logged riparian treatments than in unaltered riparian treatments. In addition, salamanders significantly reduced their terrestrial habitat use following riparian logging with both the average distance from the stream and the relative abundance of salamanders decreasing. It is unlikely that salamanders will persist in highly modified riparian habitats, as we measured significantly reduced body conditions over short periods of time at these sites. We present corroborative evidence that salamanders evacuate the riparian habitat following intensive riparian logging, emigrating to adjacent headwater streams. Our results underscore the sensitivity of stream salamanders to riparian habitat alteration as well as the importance of riparian buffers in preserving amphibian assemblages.     

Liana habitat and host preferences in northern temperate forests

Lianas and other climbers are important ecological and structural components of forest communities. Like other plants, their abundance in a given habitat depends on a variety of factors, such as light, soil moisture and nutrients. However, since lianas require external support, host tree characteristics also influence their distribution. Lianas are conspicuous life forms in tropical regions, but in temperate areas, where they are less prominent, little is known about factors that control their distributions in these forests. We surveyed the climbing plant species in 20 mature (100 years and greater) forested habitats in the Midwest USA at a variety of levels from simple presence/absence, to ground layer abundances, to those species that had ascended trees. We also examined attributes of the tree species with climbers attached to them. Using cluster analysis, we distinguished five different tree communities in our survey locations. We determined that 25% of the trees we surveyed had one or more lianas attached to it, with Parthenocissus quinquefolia (Virginia creeper) the most common climbing species encountered. Canopy cover and soil attributes both influenced climber species presence/absence and ground layer climber abundance. The proportion of liana species of a given climbing type (roots, stem twiner, tendril climber) was significantly related to the DBH of the host tree, with more root climbers and fewer stem and tendril climbers on large trees. In general, the DBH of climbing lianas had a significant positive relationship to the DBH of the host tree; however this varied by the identity of the liana and the tree species. The greater the DBH of the host tree, the higher the probability that it was colonized by one or more lianas, with tree species such as Pinus banksiana (jack pine) and Quercus alba (white oak) being more susceptible to liana colonization than others. Finally, some liana species such as Celastrus scandens (American bittersweet) showed a preference for certain tree species (i.e., P. banksiana) as hosts. The information obtained about the relationship between the tree and climber community in this study provides insight into some of the factors that influence liana distributions in understudied temperate forest habitats and how lianas contribute to the structure of these mature forests. In addition, these data can provide a point of comparison to other liana communities in both temperate and tropical regions.     

Field maple and hornbeam populations along a 4-m elevation gradient in an alluvial forest

Tree species composition of Central European alluvial hardwood forests has changed with the arrival of flood-intolerant and mesic species. Within this group of tree species, a dominant role is played by field maple (Acer campestre) and European hornbeam (Carpinus betulus). This study was performed in the Lanzhot natural forests at the confluence of the Morava and the Dyje Rivers, which are considered to be one of the most natural alluvial hardwood forests in Central Europe and where the absence of the direct influence by humans for 75 years has allowed spontaneous development. Our basic research questions were as follows: (1) does the mutual proportion and structure of field maple and hornbeam populations change along an elevation gradient of 4 m in an alluvial forest and (2) does the tree spatial pattern of field maple and hornbeam change along this gradient? The study found significant differences in the development of hornbeam and field maple populations with increasing elevation in an alluvial hardwood forest. While the strength of the hornbeam population clearly increases with increasing elevation, the field maple population does not. Compared to hornbeam, field maple is closer to the r-strategy side of the K-r continuum on alluvial sites. Our study reveals that field maple and hornbeam are mainly distributed in clusters on alluvial sites. Both species are concentrated at places with lower flooding intensity, i.e. to higher elevation sites. The study shows that tree spatial patterns could change dynamically along a short elevation gradient in alluvial hardwood forest.     

Age structure and regeneration of subalpine fir (Abies fargesii) forests across an altitudinal range in the Qinling Mountains,China

Age structure and regeneration dynamics of subalpine fir (Abies fargesii) forest were studied across the altitudinal range in both the north and south aspects of the Qinling Mountains, China. Ages of individual fir trees were determined based on the number of rings counted from cores and the number of years to reach coring height estimated using age–height regression. Fir age structure and regeneration dynamics were similar in both the north and south aspects. A unimodal population age structure was found at the low- and mid-elevations in both aspects, indicating that environmental factors might play an important role in shaping A. fargesii age structure and regeneration at those sites. There was a recruitment pulse during the time period 1830–1890 at each altitudinal site, but no stem recruitment occurred at the low- and mid-elevations in the last century, which might be attributed to the intensive cover of understory bamboo. Fir trees were, however, persistently recruited at the upper limits during the last 150 years, and the fir tree density at the upper limits was significantly higher than that at the lower limits in both aspects. The fir population at the upper limits showed a significant increase in recruitment and stem density relative to the fir population at the low- and mid-elevations in the last century. We propose that the differences in recruitment might promote variations in stand structure and regeneration dynamics of the subalpine fir forests along the altitudinal gradient in the Qinling Mountains, China.     

Does the effect of forest roads extend a few meters or more into the adjacent forest? A study on understory plant diversity in managed oak stands

Roads are recognised as having different ecological roles such as barrier, corridor or habitat, but the spatial extent of road effects on plant communities in forests remains unclear. We studied the effect of forest road distance on plant understory diversity at 20 sites in young and adult oak stands in a French lowland forest with a long history of management and road construction. All vascular and bryophyte species were collected at five distances ranging from the road verge to 100 m into the adjacent forest stand. We analysed species composition, individual species response, a priori life-history traits response – life form, habitat preference and dispersal mode – and environmental indicator values in relation to road distance and stand age. Plant composition strongly differed between road verge and forest interior habitats. The main road effect extended less than 5 m into the forest stand. A third habitat was detected at the forest-road edge resulting from the road effect on light and soil conditions, and from edge-specific topography. Non-forest species were almost absent from the forest interior. In contrast, many bryophytes and several vascular plants kept away from the road. We identified a posteriori six species groups that better explained the variability of plant response profiles than a priori life-history traits. Plant response to road distance was also dependent on stand age: some species colonised from the road into the forest interior in young stands following regeneration cutting, while other species displayed the reverse pattern in adult stands once canopy closed above the forest road. Even if the depth of forest road effect measured in lowland managed stands was narrow, building of a new forest road has non-negligible effects on plant population dynamics. Forest managers should take into account the impacts of roads on biodiversity, since the expected intensification of silviculture in response to global changes is set to accentuate the effect of forest roads. We recommend further study on the role of dispersal by vehicles (i.e. agestochory) in road effects.     

Long-term changes in two boreal landscapes with different management histories

Abstract

Forest fragmentation increases the amount of edge habitats in landscape. Despite the profound ecological influences that edges may have, the patterns and processes of edge formation have largely remained unexplored. The aim of this study was to find answers to three questions: (1) How have the landscape structure and composition, as measured by different successional stages, changed over a period of about 50years in forested landscapes in southern Finland? (2) What are the differences in the amount of edge and interior habitat between successive years? (3) How does the forest ownership, state or private, affect the prevalence of edges? Digitized aerial photographs taken in 1941 and 1944 (period1), 1969 (period2) and 1997 (period3) were used to study the prevalence of different successional stages, area of interior mature forest and edge habitats in two nearby 10km² forest areas with private and state ownership, respectively. The forest composition was similar in the two forest areas, with mature forests being replaced by younger development stages. The area of interior mature forest decreased dramatically from period1 to period2. Assuming an edge width of 100m, the proportion of edge habitat increased from 30% to 61% in the state forest and from 26% to 76% in private forest. The detected changes and their possible consequences to species suggest that management of different types of edges and converging edges should receive considerable attention in the future.     

Dynamics and drivers of post-windthrow recovery in managed mixed mountain forests of Slovenia

Large and severe disturbances may erode the resilience of temperate forest ecosystems and alter their recovery dynamics, especially under global change. We investigated mid-term recovery in mixed mountain forests in Slovenia after three independent severe windstorms in 2008 created large disturbed patches. Across a network of 102 permanent plots and three inventories over the 11-year post-disturbance period, we monitored trends in density, composition, and structure of regeneration, which are key indicators of forest resilience. Ecological drivers of regeneration, including topography, microsites, and biotic interactions, were analysed using linear mixed models. We quantitatively assessed physiognomic recovery by comparing regeneration densities with the restocking target used in forest practice, and compositional recovery by comparison with pre-disturbance stand composition. Regeneration densities and structure tended to converge among post-disturbance treatments (planting vs. natural regeneration) 11 years post-disturbance, as density of natural regeneration substantially dropped between the second and third inventory. Some drivers of recovery (i.e. ground vegetation and distance to the forest edge) varied over time, while the effect of elevation on regeneration density was consistently negative. The results indicate that the forest sites generally show adequate resilience to large-scale wind disturbances, in terms of physiognomic recovery, but not in terms of rapid compositional recovery, as pioneer and light-demanding tree species increased in share compared to the pre-disturbance stands.

     

Landscape-level effects of forest management on faunal diversity in bottomland hardwoods

Forest management activities potentially influence ecosystems at many spatial scales. For most forest systems, influences at the stand level have been most intensively studied and are best understood. Management impacts at the larger, landscape scale are poorly understood and many hypotheses regarding landscape-level effects remain untested. This lack of knowledge is particularly acute in bottomland hardwood forest (BLH) ecosystems. Most hypotheses regarding landscape-level impacts were derived from theories about island biogeography and metapopulations. Thus, species presence and productivity sometimes are viewed as functions of patch characteristics such as size, shape, amount of edge, degree of isolation from larger, similar habitats, time since isolation, and dispersal, immigration, and extinction rates. Recommendations for mitigating fragmentation effects often include maintenance of reserves, increasing patch size, reducing edges, and enhancing connectivity through the use of corridors. While many of these theories are intuitively sound, there are few data to demonstrate their effectiveness in landscapes dominated by managed forests, including BLH forests. We suggest that high priority be given to using adaptive management to simultaneously test hypotheses about how biotic communities function in managed, BLH landscapes. Such information would help managers understand the consequences of their activities, provide them with more flexibility, and improve their ability to protect biological diversity while also meeting society's needs for forest resources.     

Estimating breast height diameter and volume from stump diameter for three economically important species in Turkey

Abstract

In Fennoscandia, the concept of woodland key habitats has become one of the key concepts when defining hotspots for forest biodiversity. There is a serious lack of studies, however, in which the diversity value of the assumed key habitats has been assessed for any groups of organisms. The aim of this study was to investigate whether the woodland key habitats as defined in the Finnish Forest Act can be advocated as diversity hotspots for polypores, a group of wood-decaying fungi including several red-listed species and species used as indicators for conservation value of forests. The study area was situated in the southern boreal zone, in eastern Finland. In total, 72 woodland key habitat sites representing six different habitat types, and 12 production forest sites as controls were investigated for their polypore assemblages. A total of 2077 records of 93 species was made, of which only 17 records of nine species were red-listed. On average, key habitats hosted more species than control forests, but of the six habitat types, only fresh and mesic–moist herb-rich forests differed significantly in species number from the control forests. Compared with control forests, key habitats can maintain rich polypore flora but, because of the low number of red-listed species found, they are likely to be of little help in the conservation of threatened polypores.     

National assessment of the fragmentation, accessibility and anthropogenic pressure on the forests in Mexico

Forest managers and policy makers increasingly demand to have access to estimates of forest fragmentation,human accessibility to forest areas and levels of anthropogenic pressure on the remaining forests to integrate them into monitoring systems,management and conservation plans.Forest fragmentation is defined as the breaking up of a forest unit,where the number of patches and the amount of expose edge increase while the amount of core area decreases.Forest fragmentation studies in Mexico have been limited to local or regional levels and have concentrated only on specific forest types.This paper presents an assessment of the fragmentation of all forest types at the national level,their effective proximity to anthropogenic influences,and the development of an indicator of anthropogenic pressure on the forests areas.Broadleaf forests,tropical evergreen forests and tropical dry deciduous forests show the greatest fragmentation.Almost half(47%) of the tropical forests are in close effective proximity to anthropogenic influences and only 12% of their area can be considered isolated from anthropogenic influences.The values for the temperate forests are 23% and 29% respectively.Anthropogenic pressure in the immediate vicinity of anthropogenic activities is much higher in the tropical forests(75 in a scale 0-100) than in the temperate forests(30).When considering these results jointly,the tropical forests,and more specifically,the tropical evergreen forests and tropical dry deciduous forests are under the greatest pressure and risks of degradation.     

Effects of non-native spruce plantations on small mammal communities in subarctic birch forests

Voles and shrews are key species in northern forest ecosystems. Thus, it is important to quantify to what extent new forestry practices such as planting of non-native tree species impact these small mammals. In northern Norway stands of coastal subarctic birch forests have increasingly been converted to non-native spruce stands during the last century. This leads to changes in the forest floor vegetation and soil conditions that can be expected to negatively impact the community of ground-dwelling small mammals. In this 10-year trapping study we contrasted seasonal small mammal population abundances in spruce plantations with four birch forest varieties. Six different small mammal species were trapped (in descending order of abundance; common shrew Sorex araneus, red vole Myodes rutilus, field vole Microtus agrestis, grey-sided vole M. rufocanus, pygmy shrew S. minutus and water shrew Neomys fodiens). None of the voles appeared to exhibit temporal dynamics resembling population cycles. The three most numerous species were clearly less abundant in the spruce plantations compared to the other forest types. Autumn abundances were most impacted by spruce plantations, indicating that growth rates in the reproductive season were more influenced than winter declines. Species associated with productive forest habitats (i.e. field vole and common shrew) were most impacted by tree species conversion. Still young spruce plantations inter-mixed with birch trees and the ecotone habitat, sustained small mammal abundances comparable to the native birch forests. This implies that managing spruce plantations to maintain a mix of different tree species and high spatial heterogeneity (i.e. more ecotones), will reduce the negative impacts on the small mammal community. On the contrary, if young spruce plantations, as they age become spruce monocultures covering larger parts of the landscapes than they do presently, the negative effects on small mammal communities may be larger than observed in the present study.     

Patterns in spatial extent of gap influence on understory plant communities

Gap formation in forests can have impacts on forest ecosystems beyond the physical boundary of the canopy opening. The extent of gap influence may affect responses of many components of forest ecosystems to gap formation on stand and landscape scales. In this study, spatial extent of gap influence on understory plant communities was investigated in and around 0.1 and 0.4 ha harvested canopy gaps in four young Douglas-fir (Psuedotsuga menziesii) dominated stands in western Oregon. In larger gaps, the influence of gap creation on understory plant communities in surrounding forests was minimal. The area showing evidence of gap influence extended a maximum of 2 m beyond the edge of the canopy opening, suggesting that the area affected by gap creation did not differ greatly from the area of physical canopy removal. In smaller gaps, influence of the gap did not extend to the edge of the canopy opening. In fact, the area in which understory vegetation was influenced by gap creation was smaller than the physical canopy opening. Gap influence appears to be limited to areas where ruderal or competitor species are able to replace stress-tolerator species, likely due to elimination or reduction of these species by physical disturbance or competition. The limited gap influence extent exhibited here indicates that gap creation may not have a significant effect on understory plant communities beyond the physical canopy opening. This suggests a limited effectiveness of gaps, especially smaller gaps, as a tool for management of understory plant diversity, and perhaps biodiversity in general, on a larger scale.