Response Time of Wetland Biodiversity to Road Construction on Adjacent Lands

Abstract: Road construction may result in significant loss of biodiversity at both local and regional scales due to restricted movement between populations, increased mortality, habitat fragmentation and edge effects, invasion by exotic species, or increased human access to wildlife habitats, all of which are expected to increase local extinction rates or decrease local recolonization rates. Species loss is unlikely to occur immediately, however. Rather, populations of susceptible species are expected to decline gradually after road construction, with local extinction occurring sometime later. We document lags in wetland biodiversity loss in response to road construction by fitting regression models that express species richness of different taxa ( birds, mammals, plants, and herptiles) as a function of both current and historical road densities on adjacent lands. The proportion of variation in herptile and bird richness explained by road densities increased significantly when past densities were substituted for more current densities in multiple regression models. Moreover, for vascular plants, birds, and herptiles, there were significant negative effects of historical road densities when the most current densities were controlled statistically. Our results provide evidence that the full effects of road construction on wetland biodiversity may be undetectable in some taxa for decades. Such lags in response to changes in anthropogenic stress have important implications for land-use planning and environmental impact assessment.     

Do birds and beetles show similar responses to urbanization?

To date, the vast majority of studies in urban areas have been carried out on birds, yet it is not known whether the responses of birds to urbanization are congruent with those of other taxa. In this paper, we compared the responses of breeding birds and carabid beetles to urbanization, specifically asking whether the emerging generalizations of the effects of extreme levels of urbanization on birds (declines in total species richness and the richness of specialist species, increases in total abundance and the abundances of native generalist and introduced species, and community simplification, including increasing similarity) could also be applied to ground beetles. We also directly tested for congruence between birds and ground beetles using correlations between variables describing bird and beetle community structure and correlations between bird and beetle distance matrices describing community dissimilarity between pairs of sampling locations. Breeding bird and carabid beetle community data were collected in Ottawa, Ontario, and Gatineau, Quebec, Canada, in two groups of sites: developed sites representing the predictor variable within-site housing density, and forested sites adjacent to development representing the predictor variable neighboring housing density (each site was 0.25 km2). Breeding birds and carabid beetles do not respond similarly to increasing within-site housing density but do exhibit some similar responses to increasing neighboring housing density. Birds displayed strong declines in diversity, compositional changes, and community simplification in response to increasing within-site housing density. Forest and introduced species of birds and beetles responded similarly to increasing housing density within a site, but responses of overall diversity and open-habitat species richness and patterns of community simplification differed between birds and beetles. Increasing neighboring housing density resulted in increases in the abundances of introduced birds and introduced beetles and similar patterns of community simplification in both taxa. To better understand and mitigate the effects of urbanization on biodiversity, we suggest that, in addition to the responses of birds, future research should focus on the responses of other taxa in the urban matrix.     

Effects of landscape design of forest reserves on Saproxylic beetle diversity

Increasing the density of natural reserves in the forest landscape may provide conservation benefits for biodiversity within and beyond reserve borders. We used 2 French data sets on saproxylic beetles and landscape cover of forest reserves (LCFR) to test this hypothesis: national standardized data derived from 252 assessment plots in managed and reserve stands in 9 lowland and 5 highland forests and data from the lowland Rambouillet forest, a forested landscape where a pioneer conservation policy led to creation of a dense network of reserves. Abundance of rare and common saproxylic species and total saproxylic species richness were higher in forest reserves than in adjacent managed stands only in highland forests. In the lowland regional case study, as LCFR increased total species richness and common species abundance in reserves increased. In this case study, when there were two or more reserve patches, rare species abundance inside reserves was higher and common species richness in managed stands was higher than when there was a single large reserve. Spillover and habitat amount affected ecological processes underlying these landscape reserve effects. When LCFR positively affected species richness and abundance in reserves or managed stands, >12‐20% reserve cover led to the highest species diversity and abundance. This result is consistent with the target of 17% forested land area in reserves set at the Nagoya biodiversity summit in 2010. Therefore, to preserve biodiversity we recommend at least doubling the current proportion of forest reserves in European forested landscapes.     

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

Abstract: 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.     

Patterns of animal diversity in different forms of tree cover in agricultural landscapes.

As tropical regions are converted to agriculture, conservation of biodiversity will depend not only on the maintenance of protected forest areas, but also on the scope for conservation within the agricultural matrix in which they are embedded. Tree cover typically retained in agricultural landscapes in the neotropics may provide resources and habitats for animals, but little is known about the extent to which it contributes to conservation of animal species. Here, we explore the animal diversity associated with different forms of tree cover for birds, bats, butterflies, and dung beetles in a pastoral landscape in Nicaragua. We measured species richness and abundance of these four animal taxa in riparian and secondary forest, forest fallows, live fences, and pastures with high and low tree cover. We recorded over 20,000 individuals of 189 species including 14 endangered bird species. Mean abundance and species richness of birds and bats, but not dung beetles or butterflies, were significantly different among forms of tree cover. Species richness of bats and birds was positively correlated with tree species richness. While the greatest numbers of bird species were associated with riparian and secondary forest, forest fallows, and pastures with >15% tree cover, the greatest numbers of bat species were found in live fences and riparian forest. Species assemblages of all animal taxa were different among tree cover types, so that maintaining a diversity of forms of tree cover led to conservation of more animal species in the landscape as a whole. Overall, the findings indicate that retaining tree cover within agricultural landscapes can help conserve animal diversity, but that conservation efforts need to target forms of tree cover that conserve the taxa that are of interest locally. Preventing the degradation of remaining forest fragments is a priority, but encouraging farmers to maintain tree cover in pastures and along boundaries may also make an important contribution to animal conservation.     

Riparian forest composition affects stream litter decomposition despite similar microbial and invertebrate communities

Cross-boundary flows of energy and nutrients link biodiversity and functioning in adjacent ecosystems. The composition of forest tree species can affect the structure and functioning of stream ecosystems due to physical and chemical attributes, as well as changes in terrestrial resource subsidies. We examined how variation in riparian canopy composition (coniferous, deciduous, mixed) affects adjacent trophic levels (invertebrate and microbial consumers) and decomposition of organic matter in small, coastal rainforest streams in southwestern British Columbia. Breakdown rates of higher-quality red alder (Alnus rubra) litter were faster in streams with a greater percentage of deciduous than coniferous riparian canopy, whereas breakdown rates of lower-quality western hemlock (Tsuga heterophylla) litter were independent of riparian forest composition. When invertebrates were excluded using fine mesh, breakdown rates of both litter species were an order of magnitude less and were not significantly affected by riparian forest composition. Stream invertebrate and microbial communities were similar among riparian forest composition, with most variation attributed to leaf litter species. Invertebrate taxa richness and shredder biomass were higher in A. rubra litter; however, taxa evenness was greatest for T. heterophylla litter and both litter species in coniferous streams. Microbial community diversity (determined from terminal restriction fragment length polymorphisms) was unaffected by riparian forest or litter species. Fungal allele richness was higher than bacterial allele richness, and microbial communities associated with lower-quality T. heterophylla litter had higher diversity (allele uniqueness and richness) than those associated with higher-quality A. rubra litter. Percent variation in breakdown rates was mostly attributed to riparian forest composition in the presence of invertebrates and microbes; however, stream consumer biodiversity at adjacent trophic levels did not explain these patterns. Riparian and stream ecosystems and their biotic communities are linked through exchange and decomposition of detrital resources, and we provide evidence that riparian forest composition affects stream ecosystem catabolism despite similarities in microbial and invertebrate communities.     

Countryside Biogeography of Moths in a Fragmented Landscape: Biodiversity in Native and Agricultural Habitats

Abstract: Studies of fragmented landscapes, especially in the tropics, have traditionally focused on the native fragments themselves, ignoring species distributions in surrounding agricultural or other human-dominated areas. We sampled moth species richness within a 227-ha forest fragment and in four surrounding agricultural habitats (coffee, shade coffee, pasture, and mixed farms) in southern Costa Rica. We found no significant difference in moth species richness or abundance among agricultural habitats, but agricultural sites within 1 km of the forest fragment had significantly higher richness and abundance than sites farther than 3.5 km from the fragment. In addition, species composition differed significantly between distance classes ( but not among agricultural habitats), with near sites more similar to forest than far sites. These results suggest that (1) different agricultural production regimes in this region may offer similar habitat elements and thus may not differ substantially in their capacities to support native moth populations and (2) that the majority of moths may utilize both native and agricultural habitats and move frequently between them, forming "halos" of relatively high species richness and abundance around forest fragments. Correlations between species richness and the amount of nearby forest cover, measured over circles of various radii around the sites, suggest that halos extend approximately 1.0–1.4 km from the forest edge. The extent of these halos likely differs among taxa and may influence their ability to survive in fragmented landscapes.     

Biodiversity Loss in Latin American Coffee Landscapes: Review of the Evidence on Ants,Birds, and Trees

Abstract: Studies have documented biodiversity losses due to intensification of coffee management (reduction in canopy richness and complexity). Nevertheless, questions remain regarding relative sensitivity of different taxa, habitat specialists, and functional groups, and whether implications for biodiversity conservation vary across regions. We quantitatively reviewed data from ant, bird, and tree biodiversity studies in coffee agroecosystems to address the following questions: Does species richness decline with intensification or with individual vegetation characteristics? Are there significant losses of species richness in coffee‐management systems compared with forests? Is species loss greater for forest species or for particular functional groups? and Are ants or birds more strongly affected by intensification? Across studies, ant and bird richness declined with management intensification and with changes in vegetation. Species richness of all ants and birds and of forest ant and bird species was lower in most coffee agroecosystems than in forests, but rustic coffee (grown under native forest canopies) had equal or greater ant and bird richness than nearby forests. Sun coffee (grown without canopy trees) sustained the highest species losses, and species loss of forest ant, bird, and tree species increased with management intensity. Losses of ant and bird species were similar, although losses of forest ants were more drastic in rustic coffee. Richness of migratory birds and of birds that forage across vegetation strata was less affected by intensification than richness of resident, canopy, and understory bird species. Rustic farms protected more species than other coffee systems, and loss of species depended greatly on habitat specialization and functional traits. We recommend that forest be protected, rustic coffee be promoted, and intensive coffee farms be restored by augmenting native tree density and richness and allowing growth of epiphytes. We also recommend that future research focus on potential trade‐offs between biodiversity conservation and farmer livelihoods stemming from coffee production.     

The importance of agricultural lands for Himalayan birds in winter

The impacts of land‐use change on biodiversity in the Himalayas are poorly known, notwithstanding widespread deforestation and agricultural intensification in this highly biodiverse region. Although intact primary forests harbor many Himalayan birds during breeding, a large number of bird species use agricultural lands during winter. We assessed how Himalayan bird species richness, abundance, and composition during winter are affected by forest loss stemming from agriculture and grazing. Bird surveys along 12 elevational transects within primary forest, low‐intensity agriculture, mixed subsistence agriculture, and intensively grazed pastures in winter revealed that bird species richness and abundance were greatest in low‐intensity and mixed agriculture, intermediate in grazed pastures, and lowest in primary forest at both local and landscape scales; over twice as many species and individuals were recorded in low‐intensity agriculture than in primary forest. Bird communities in primary forests were distinct from those in all other land‐use classes, but only 4 species were unique to primary forests. Low‐, medium‐, and high‐intensity agriculture harbored 32 unique species. Of the species observed in primary forest, 80% had equal or greater abundance in low‐intensity agricultural lands, underscoring the value of these lands in retaining diverse community assemblages at high densities in winter. Among disturbed landscapes, bird species richness and abundance declined as land‐use intensity increased, especially in high‐intensity pastures. Our results suggest that agricultural landscapes are important for most Himalayan bird species in winter. But agricultural intensification—especially increased grazing—will likely result in biodiversity losses. Given that forest reserves alone may inadequately conserve Himalayan birds in winter, comprehensive conservation strategies in the region must go beyond protecting intact primary forests and ensure that low‐intensity agricultural lands are not extensively converted to high‐intensity pastures.     

Mitigating the impact of oil‐palm monoculture on freshwater fishes in Southeast Asia

Anthropogenic land‐cover change is driving biodiversity loss worldwide. At the epicenter of this crisis lies Southeast Asia, where biodiversity‐rich forests are being converted to oil‐palm monocultures. As demand for palm oil increases, there is an urgent need to find strategies that maintain biodiversity in plantations. Previous studies found that retaining forest patches within plantations benefited some terrestrial taxa but not others. However, no study has focused on aquatic taxa such as fishes, despite their importance to human well‐being. We assessed the efficacy of forested riparian reserves in conserving freshwater fish biodiversity in oil‐palm monoculture by sampling stream fish communities in an oil‐palm plantation in Central Kalimantan, Indonesia. Forested riparian reserves maintained preconversion local fish species richness and functional diversity. In contrast, local and total species richness, biomass, and functional diversity declined markedly in streams without riparian reserves. Mechanistically, riparian reserves appeared to increase local species richness by increasing leaf litter cover and maintaining coarse substrate. The loss of fishes specializing in leaf litter and coarse substrate decreased functional diversity and altered community composition in oil‐palm plantation streams that lacked riparian reserves. Thus, a land‐sharing strategy that incorporates the retention of forested riparian reserves may maintain the ecological integrity of fish communities in oil‐palm plantations. We urge policy makers and growers to make retention of riparian reserves in oil‐palm plantations standard practice, and we encourage palm‐oil purchasers to source only palm oil from plantations that employ this practice.     

Consistency of effects of tropical‐forest disturbance on species composition and richness relative to use of indicator taxa

Lawton et al. (1998) found, in a highly cited study, that the species richness of 8 taxa each responds differently to anthropogenic disturbance in Cameroon forests. Recent developments in conservation science suggest that net number of species is an insensitive measure of change and that understanding which species are affected by disturbance is more important. It is also recognized that all disturbance types are not equal in their effect on species and that grouping species according to function rather than taxonomy is more informative of responses of biodiversity to change. In a reanalysis of most of the original Cameroon data set (canopy and ground ants, termites, canopy beetles, nematodes, and butterflies), we focused on changes in species and functional composition rather than richness and used a more inclusive measure of forest disturbance based on 4 component drivers of change: years since disturbance, tree cover, soil compaction, and degree of tree removal. Effects of disturbance on compositional change were largely concordant between taxa. Contrary to Lawton et al.’s findings, species richness for most groups did not decline with disturbance level, providing support for the view that trends in species richness at local scales do not reflect the resilience of ecosystems to disturbance. Disturbance affected species composition more strongly than species richness for butterflies, canopy beetles, and litter ants. For these groups, disturbance caused species replacements rather than just species loss. Only termites showed effects of disturbance on species richness but not composition, indicating species loss without replacement. Although disturbance generally caused changes in composition, the strength of this relationship depended on the disturbance driver. Butterflies, litter ants, and nematodes were correlated with amount of tree cover, canopy beetles were most strongly correlated with time since disturbance, and termites were most strongly correlated with degree of soil disturbance. There were moderately divergent responses to disturbance between functional feeding groups. Disturbance was most strongly correlated with compositional differences of herbivores within beetles and nematodes and humus feeders within termites. Our results suggest that consideration of the impact of different forms of disturbance on species and functional composition, rather than on net numbers of species, is important when assessing the impacts of disturbance on biodiversity.     

Recovery Patterns of Understory Herbs and Their Use as Indicators of Deciduous Forest Regeneration

Abstract: Habitat fragmentation has reduced the richness of native species of forests in northeastern North America. Despite recent large-scale increases in forest cover, studies indicate that understory herbaceous plant communities may take many decades to recover. We studied recovery patterns of vegetation following up to 35 years of forest regeneration in restored former cottage and road sites at Point Pelée National Park, Ontario, Canada, to assess the vulnerability of the understory herbaceous species. Overall, there were no significant differences in the diversity of native species between restored and relatively undisturbed reference sites. There was, however, significant among-site variation in the composition of the native species component of these plant communities. When only restored sites were examined, variation in native species composition was associated with time since site restoration, soil moisture, canopy cover, and distance to continuous forest. Native species were assigned vulnerability rankings according to their relative occurrence in reference and restored sites. Spring-flowering herbs, with ant- or gravity-dispersed seeds, were absent from restored sites and were defined as highly vulnerable. In contrast, summer- and fall-flowering herbs, with vertebrate- and wind-dispersed seeds, dominated restored sites and were less vulnerable. Species of low and intermediate vulnerability had colonized restored sites successfully, and the latter should function as indicators of recovery. In contrast, species with high vulnerability rankings had not recovered at all and, because of their limited dispersal ranges, may recolonize restored sites only if they are actively reintroduced.     

Thresholds of species loss in Amazonian deforestation frontier landscapes

In the Brazilian Amazon, private land accounts for the majority of remaining native vegetation. Understanding how land‐use change affects the composition and distribution of biodiversity in farmlands is critical for improving conservation strategies in the face of rapid agricultural expansion. Working across an area exceeding 3 million ha in the southwestern state of Rondônia, we assessed how the extent and configuration of remnant forest in replicate 10,000‐ha landscapes has affected the occurrence of a suite of Amazonian mammals and birds. In each of 31 landscapes, we used field sampling and semistructured interviews with landowners to determine the presence of 28 large and medium sized mammals and birds, as well as a further 7 understory birds. We then combined results of field surveys and interviews with a probabilistic model of deforestation. We found strong evidence for a threshold response of sampled biodiversity to landscape level forest cover; landscapes with <30–40% forest cover hosted markedly fewer species. Results from field surveys and interviews yielded similar thresholds. These results imply that in partially deforested landscapes many species are susceptible to extirpation following relatively small additional reductions in forest area. In the model of deforestation by 2030 the number of 10,000‐ha landscapes under a conservative threshold of 43% forest cover almost doubled, such that only 22% of landscapes would likely to be able to sustain at least 75% of the 35 focal species we sampled. Brazilian law requires rural property owners in the Amazon to retain 80% forest cover, although this is rarely achieved. Prioritizing efforts to ensure that entire landscapes, rather than individual farms, retain at least 50% forest cover may help safeguard native biodiversity in private forest reserves in the Amazon. Umbrales de Pérdida de Especies en los Paisajes Fronterizos de Deforestación en el Amazonas Ochoa‐Quintero     

Partitioning vegetation response to anthropogenic stress to develop multi-taxa wetland indicators.

Emergent plants can be suitable indicators of anthropogenic stress in coastal wetlands if their responses to natural environmental variation can be parsed from their responses to human activities in and around wetlands. We used hierarchical partitioning to evaluate the independent influence of geomorphology, geography, and anthropogenic stress on common wetland plants of the U.S. Great Lakes coast and developed multi-taxa models indicating wetland condition. A seven-taxon model predicted condition relative to watershed-derived anthropogenic stress, and a four-taxon model predicted condition relative to within-wetland anthropogenic stressors that modified hydrology. The Great Lake on which the wetlands occurred explained an average of about half the variation in species cover, and subdividing the data by lake allowed us to remove that source of variation. We developed lake-specific multi-taxa models for all of the Great Lakes except Lake Ontario, which had no plant species with significant independent effects of anthropogenic stress. Plant responses were both positive (increasing cover with stress) and negative (decreasing cover with stress), and plant taxa incorporated into the lake-specific models differed by Great Lake. The resulting models require information on only a few taxa, rather than all plant species within a wetland, making them easier to implement than existing indicators.     

Spatial patterns of carbon,biodiversity, deforestation threat,and REDD+ projects in Indonesia

There are concerns that Reduced Emissions from Deforestation and forest Degradation (REDD+) may fail to deliver potential biodiversity cobenefits if it is focused on high carbon areas. We explored the spatial overlaps between carbon stocks, biodiversity, projected deforestation threats, and the location of REDD+ projects in Indonesia, a tropical country at the forefront of REDD+ development. For biodiversity, we assembled data on the distribution of terrestrial vertebrates (ranges of amphibians, mammals, birds, reptiles) and plants (species distribution models for 8 families). We then investigated congruence between different measures of biodiversity richness and carbon stocks at the national and subnational scales. Finally, we mapped active REDD+ projects and investigated the carbon density and potential biodiversity richness and modeled deforestation pressures within these forests relative to protected areas and unprotected forests. There was little internal overlap among the different hotspots (richest 10% of cells) of species richness. There was also no consistent spatial congruence between carbon stocks and the biodiversity measures: a weak negative correlation at the national scale masked highly variable and nonlinear relationships island by island. Current REDD+ projects were preferentially located in areas with higher total species richness and threatened species richness but lower carbon densities than protected areas and unprotected forests. Although a quarter of the total area of these REDD+ projects is under relatively high deforestation pressure, the majority of the REDD+ area is not. In Indonesia at least, first‐generation REDD+ projects are located where they are likely to deliver biodiversity benefits. However, if REDD+ is to deliver additional gains for climate and biodiversity, projects will need to focus on forests with the highest threat to deforestation, which will have cost implications for future REDD+ implementation.     

Strategic Habitats for Biodiversity Conservation in Florida

Abstract: Privately owned lands support a large portion of the biodiversity in some areas, but procedures for identifying those private lands critical to the maintenance of biodiversity vary tremendously. We used habitat-based distribution maps in combination with population conservation goals to help identify strategic habitats on private lands in Florida. We used a vegetation map, occurrence data, and published life-history information to create habitat-based distribution maps for 179 rare taxa. We estimated the security of 130 of the taxa by overlaying public land boundaries on habitat maps and then estimating whether conservation lands satisfied a population goal of supporting at least 10 populations of approximately 200 breeding adults. The remaining taxa were evaluated in terms of number of occurrence records on conservation lands. Of the 179 taxa evaluated, existing conservation lands did not adequately protect 56. We then identified habitats on private lands that could best satisfy the minimum conservation goal or else significantly enhance the survival potential of inadequately protected taxa. Strategic habitats included a mix of large and small sites, incorporated some corridor or stepping-stone connections among habitat patches, and protected multiple species. Additional strategic habitats were identified for shorebirds, four natural plant communities, and 105 globally rare plants. The strategic habitats identified in Florida cover 1.65 million ha (12% of the land area) and would cost $8.2 billion (about 15% of Florida's annual state budget) to purchase and $122 million per year to manage. Existing conservation lands account for 3.07 million ha (22% of the land area).     

Effects of Land Use on Bird Species Richness in Sulawesi, Indonesia

Abstract:  There is still much debate over the potential value of land-use systems for the maintenance of tropical biodiversity. An increasing number of studies indicate that much forest biodiversity can also be found in the agricultural landscape matrix. Because there is little information on the potential value of land-use systems for tropical forest bird species, we conducted repeated point counts in near-primary forest, adjacent young secondary forest, modernized cacao agroforestry systems, and annual cultures at submontane elevations in central Sulawesi, Indonesia. Species richness decreased from natural forest and young secondary forest to agroforestry systems and annual cultures. Although species richness was similar between natural and young secondary forest, the number of endemic bird species was significantly lower in second-growth forest. Species composition gradually changed as the habitat changed from natural to secondary forest, agroforestry systems, and annual cultures. Despite close proximity to near-primary forest, the agroforestry systems studied supported only a few small frugivorous-nectarivorous species. Our results suggest that secondary forest could play an important role in the conservation of many Sulawesi bird species, but, although suitable for colonization, its potential to sustain populations over the long term is unknown. Improvement of the landscape matrix for biodiversity conservation through secondary habitats therefore seems desirable to enlarge the ranges of forest species, but the fight against land conversion within protected areas of the region should be of much higher importance, at least at present.     

Conservation Value of Multiple-Use Areas in East Africa

Abstract:  Despite wide agreement that strictly protected areas (World Conservation Union categories I–III) are the best strategy for conserving biodiversity, they are limited in extent and exclude many species of key conservation importance. In contrast, multiple-use management areas (categories IV–VI), comprising >60% of the world's protected-area network, are often considered of little value to biodiversity conservation, particularly in Africa, where they typically contain few charismatic large mammals. We sampled small mammals, amphibians, birds, butterflies, and trees at 41 sites along a four-step gradient of increasing human activity and decreasing conservation protection, from a well-protected Tanzanian national park to nonintensive agricultural land. Although preliminary, our results indicate that species richness of these five taxa did not decline along this gradient, but different management areas, occupying areas of largely similar habitat, hosted distinct communities of each taxon. Differences in species composition in the absence of manifest differences in species richness highlight the importance of developing landscape-scale conservation strategies and the danger of using either a limited suite of indicator taxa or umbrella species as surrogates for biodiversity. Although strictly protected areas perform a unique and vital conservation service in East Africa by protecting large mammals, areas that allow varied resource extraction activities still possess vital and complementary conservation value.     

Global mismatches in aboveground and belowground biodiversity

Human activities are accelerating global biodiversity change and have resulted in severely threatened ecosystem services. A large proportion of terrestrial biodiversity is harbored by soil, but soil biodiversity has been omitted from many global biodiversity assessments and conservation actions, and understanding of global patterns of soil biodiversity remains limited. In particular, the extent to which hotspots and coldspots of aboveground and soil biodiversity overlap is not clear. We examined global patterns of these overlaps by mapping indices of aboveground (mammals, birds, amphibians, vascular plants) and soil (bacteria, fungi, macrofauna) biodiversity that we created using previously published data on species richness. Areas of mismatch between aboveground and soil biodiversity covered 27% of Earth's terrestrial surface. The temperate broadleaf and mixed forests biome had the highest proportion of grid cells with high aboveground biodiversity but low soil biodiversity, whereas the boreal and tundra biomes had intermediate soil biodiversity but low aboveground biodiversity. While more data on soil biodiversity are needed, both to cover geographic gaps and to include additional taxa, our results suggest that protecting aboveground biodiversity may not sufficiently reduce threats to soil biodiversity. Given the functional importance of soil biodiversity and the role of soils in human well-being, soil biodiversity should be considered further in policy agendas and conservation actions by adapting management practices to sustain soil biodiversity and considering soil biodiversity when designing protected areas.     

Effect of Invasive Plant Species on Temperate Wetland Plant Diversity

Abstract:  Invasive species are a major threat to global biodiversity and an important cause of biotic homogenization of ecosystems. Exotic plants have been identified as a particular concern because of the widely held belief that they competitively exclude native plant species. We examined the correlation between native and invasive species richness in 58 Ontario inland wetlands. The relationship between exotic and native species richness was positive even when we controlled for important covarying factors. In addition, we examined the relationship between the abundance of four native species (  Typha latifolia, T. angustifolia, Salix petiolaris, Nuphar variegatum ) and four invasive species (  Lythrum salicaria, Hydrocharis morsus-ranae, Phalaris arundinacea, Rhamnus frangula ) that often dominate temperate wetlands and native and rare native species richness. Exotic species were no more likely to dominate a wetland than native species, and the proportion of dominant exotic species that had a significant negative effect on the native plant community was the same as the proportion of native species with a significant negative effect. We conclude that the key to conservation of inland wetland biodiversity is to discourage the spread of community dominants, regardless of geographical origin.