Current trends in conservation education in Japan

Conservation education (CE) is an important component of environmental education. Its goal is to teach the theory and practice of preservation and restoration of biodiversity affected by human activities so that people can increase their awareness of conservation issues and change their attitudes and behavior to promote environmental conservation.This paper describes two successful case studies to highlight trends in CE in Japan. One case is a project implemented to create “agricultural wetlands” that resulted in the establishment of a Ramsar Convention site comprised of a restored wetland and its adjacent rice paddy in a rural area near Sendai City in northern Japan. Rice paddy fields are a major component of Satoyama, which are traditional agricultural ecosystems in Japan and occupy 40% of the undeveloped landscape in Japan (Ministry of the Environment Government of Japan, 2007. Third National Biodiversity Strategy of Japan. Ministry of the Environment Government of Japan, Tokyo). Restoration of Satoyama and wetlands by local citizens is a key component of CE practices in Japan, where practical, hands-on, community-based learning is important. The second CE project, geared toward university students and citizens in Yokohama, restored degraded dragonfly ponds and created butterfly biotope in the second largest city in Japan. Restoration of habitat that is centered around highly visible, popular species such as dragonflies and butterflies also benefits other, less prominent species that share these habitats, yet allows residents to easily monitor the benefits of the project.     

Dragonfly crisis in Japan: A likely consequence of recent agricultural habitat degradation

Many Japanese dragonfly species depend on habitat complexes maintained in rice paddy systems. We postulated that recent alterations to habitat complexes in paddy systems have had adverse effects on dragonfly populations, especially those ‘once common species’ that have come to depend primarily on paddy systems following losses of natural floodplain habitats. A high proportion of Japanese lentic dragonfly species depends on paddy fields or agricultural ponds that have been extensively degraded, while lotic species can often use both paddies and natural river systems. Thus we also postulated that lentic species are more susceptible to changes in agricultural habitats and are subject to higher extinction risks than lotic species. We aimed to extend previous work on estimating dragonfly extinction risk by developing mechanistic insights into the processes involved. Postulates were tested by analyzing relationships between (1) previous quantitative extinction risk assessments for dragonfly species and (2) species’ ecological characteristics (i.e., distribution range and habitat type [lentic or lotic]). Lentic species were disproportionately represented among those with elevated extinction risk. Species with large distribution ranges were also subject to higher extinction risks than those with narrower ranges, reflecting a driving force acting at a national scale (i.e., intensive degradation of paddy systems).     

Habitat models and habitat connectivity analysis for butterflies and burnet moths - The example of Zygaena carniolica and Coenonympha arcania

In this paper, habitat models were used to predict potential habitat for endangered species, which is an important question in landscape and conservation planning. Based on logistic regression, we developed habitat distribution models for the burnet moth Zygaena carniolica and the nymphalid butterfly Coenonympha arcania in Northern Bavaria, Germany. The relation between adult occurrence and habitat parameters, including the influence of landscape context, was analyzed on 118 sites. Habitat connectivity analyses were carried out on the basis of (1) habitat suitability maps generated from these models and (2) dispersal data from mark recapture studies. Our results showed that (1) the presence of the burnet depended mainly on the presence of nectar plants and of nutrient-poor dry grasslands in direct vicinity, that of the nymphalid on larger areas of extensively used dry grasslands within 100 m vicinity in combination with small patches of higher shrubs and bushes. (2) Internal as well as external validation indicated the robustness and general applicability of the models. Transferability in time and space indicated their high potential relevance for applications in nature conservation, such as predicting possible effects of land use changes. (3) Habitat connectivity analyses revealed a high degree of habitat connectivity within the study area. Thus, we could show no effects of isolation or habitat size for both species.     

Experimental establishment of a declining dry-grassland flagship species in relation to seed origin and target environment

Supporting species persistence may involve (re)connecting suitable habitats. However, for many declining species habitat suitability and drivers of establishment are poorly known. We addressed this experimentally for a declining flagship species of dry grasslands in Germany, Armeria maritima subsp. elongata. In three regions, we sowed seeds from each of eight source populations back to their origin and to eight apparently suitable, but currently unoccupied, habitats close to the source populations. Overall, seeds germinated and seedlings established equally well in occupied and potential sites indicating that suitable habitats are available, but lack seed input. Germination and establishment varied among sowing sites. Moreover, seeds from populations of lower current connectivity established less well in new sites, and establishment was more variable among seeds from smaller than from larger populations, possibly reflecting genetic consequences of habitat fragmentation. Further, establishment across different new environments differed between seeds from different populations. As this was neither related to a home-away contrast nor to geographic or environmental distance between sites it could not clearly be attributed to local adaptation. To promote long-term persistence within this dry-grassland meta-population context we suggest increasing the density of suitable habitats and supporting dispersal connecting multiple sites, e.g. by promoting sheep transhumance, to increase current populations and their connectivity, and to colonise suitable habitats with material from different sources. We suggest that sowing experiments with characteristic species, including multiple source populations and multiple recipient sites, should be used regularly to inform connecting efforts in plant conservation.     

Winter habitat selection by two sympatric forest grouse in western Switzerland: implications for conservation

Two endangered tetraonids, the capercaillie (Tetrao urogallus) and the hazel grouse (Bonasa bonasia rupestris), are sympatric throughout part of their distribution range in central Europe. Precise information on their specific habitat requirements is needed if the coexistence of both species in exploited forests is to be maintained. We quantified winter habitat selection for both species in the upper part (1100-1600 m) of the Jura mountains (Switzerland). No preference for altitude or exposure could be detected. Capercaillie preferred open forests (including grazed forests) with a sparse canopy dominated by spruce (Picea abies) and fir (Abies alba), and avoided dense undercanopy and understorey, especially when dominated by spruce and beech (Fagus sylvatica). By contrast, hazel grouse preferred feeding sites with a dense understorey of rowan (Sorbus aucuparia), willow (Salix sp.), beech and spruce. These preferences can be related to the feeding habits and predator avoidance behaviour of both species. Coexistence thus requires a mosaic distribution of habitat types, with a matrix of open forests (30% canopy cover) where fir is favoured, and understorey kept sparse (20%). Group-cuts of mature trees should allow regeneration patches, where a dense understorey (50% cover) should provide suitable habitats for hazel grouse.     

Influence of connectivity, habitat quality and invasive species on egg and larval distributions and local abundance of crucian carp in Japanese agricultural landscapes

The quality of habitat at and around a spawning site, and the availability of movement between spawning and nonspawning habitats are likely to be important determinants for population persistence in a degraded and fragmented landscape. We assessed the influence of habitat connectivity, habitat quality and invasive species for distributions and local abundance of eggs and larvae of crucian carp (Crassius auratus complex, which is listed as “data deficient” on the Japanese Red List) in agricultural landscapes surrounding Lake Mikata, Japan, where drainage ditches and paddy fields are extensively utilised for spawning (lake or river shores are also used). We investigated the presence and abundance of eggs and larvae of crucian carp and habitat components at 146 sites across a range of presumed spawning habitats. Egg presence was affected strongly by connectivity to the lake (watercourse distance from the lake), and egg abundance was significantly influenced by both connectivity and habitat quality. In contrast, larval presence was primarily related to habitat quality. Larval abundance was influenced by connectivity and habitat quality, but the effect of connectivity was relatively low. Furthermore, larval abundance was negatively related to the presence of the invasive species red swamp crayfish (Procambarus craki) and bullfrog (Rana catesbeiana). Our findings indicate that connectivity, habitat quality and the presences of invasive species are crucial in determining suitable spawning and nursery habitats, but their relative importance may vary depending on egg and larval life stages. We suggest that restoring connectivity, improving habitat quality and removal of invasive species could be effective conservation strategies for the declining populations of crucian carp in agricultural landscapes.     

Are urban forests ecological traps for understory birds? An examination using Northern cardinals

Many studies have reported increased numbers of certain synanthropic species in urbanizing landscapes, but few have evaluated if urban habitats constitute ecological traps for these species. The Northern cardinal (Cardinalis cardinalis) was used as a model species to evaluate if urban riparian forests might act as ecological traps for understory-nesting birds. Cardinals were surveyed within 2-ha riparian forest plots within rural (n = 6) and urban (n = 6) landscapes in Ohio USA during breeding and non-breeding seasons 2003-2005. Cues used by cardinals to select habitats were identified based on measurements surrounding 219 nests and in 106 randomly-located plots and 96 systematically-located plots. Productivity of 161 cardinal pairs and survival of 180 adults were monitored from late March-September, 2003-2005. Cardinals were 1.7× (in the breeding season) to nearly 4× (in non-breeding season) more abundant in urban than rural forests, and the results suggest that these differences in abundance stemmed from urban-associated changes in habitat and microclimate features used by cardinals to select habitats. Most notably, cardinals were strongly associated with dense understory vegetation and warmer minimum January temperatures, both of which were promoted as urban development increased within the landscapes surrounding riparian forests. Although other studies suggest mismatches between the habitat cues used by cardinals and how those features affect nesting success (e.g., higher nest predation in exotic shrubs), these results provide no evidence that urban forests were acting as ecological traps for cardinals. Instead, cardinals in urban and rural forests had similar numbers of nesting attempts, young fledged over the breeding season, and apparent annual survival rates. Thus, these findings do not support for the idea that urban forests in central Ohio represent ecological traps for synanthropic understory birds.     

Scale-independent significance of river and riparian zones on three sympatric Myotis species in an agricultural landscape

Conserving biodiversity in agricultural landscapes is an urgent issue. The effective conservation of biodiversity requires plans based on species’ habitat preferences at multiple spatial scales. We examined how the foraging habitat selection of bats varied with grain size (50, 150, 250, and 350 m) and how habitat selection in the home range differed from that in the foraging habitat in an agricultural landscape. Focusing on three sympatric Myotis species (Myotis petax, Myotis gracilis, and Myotis frater), we radio-tracked 10 individuals of each species for 121 nights in Hokkaido, northern Japan. Rivers and broadleaved riparian forests were commonly preferred at multiple scales, although the preferred land-cover type was dependent on both extent and grain size for most species. The best grain sizes for predicting the foraging-habitat use of M. petax and M. gracilis were 50 and 150 m. By contrast, M. frater showed no tendency across the grain sizes. Our results indicate that it is necessary to consider both extent and grain size to understand the habitat selection of bats. Our findings also suggest that focusing primarily on preferred land-cover types at multiple scales is effective for conservation planning, given the limited resources in terms of time, manpower, and finances. Although arable did not negatively affect the selection of foraging habitats and home ranges in these bat species, preventing the loss of rivers and forests should be prioritized over preventing arable land expansion.     

Habitat structure and proximity to forest edge affect the abundance and distribution of forest-dependent birds in tropical coastal forests of southeastern Madagascar

Despite the fact that Madagascar is classified a biological `hotspot' due to having both high levels of species endemism and high forest loss, there has been no published research on how Madagascan bird species respond to the creation of a forest edge or to degradation of their habitat. In this study, we examined how forest bird communities and different foraging guilds were affected by patch habitat quality and landscape context (forest core, forest edge and matrix habitat) in the threatened littoral forests of coastal southeastern Madagascar. We quantified habitat use and community composition of birds by conducting 20 point counts in each landscape contextual element in October and November 2002. We found that littoral forest core habitats had significantly (p<0.01) more bird species than forest edge and matrix habitats. Thirty-one (68%) forest dependent species were found to be edge-sensitive. Forest edge sites had fewer species, and a higher representation of common species than forest interior sites. Twenty-nine species were found in the matrix habitat, and the majority of matrix-tolerant forest species had their greatest abundance within littoral forest edge habitats. Guild composition also changed with landscape context. Unlike other tropical studies with which we are familiar, we found that frugivorous species were edge-sensitive while sallying insectivores were edge-preferring. The majority of canopy insectivores (n=15, 88%), including all six endemic vanga species, were edge-sensitive. When habitat quality was assessed, the distributions of nine edge-sensitive species were significantly (p<0.01) affected by changes in habitat complexity and vegetation vertical structure in core or edge point counts. Therefore, we believe that changes in vegetation structure at the edge of littoral forest remnants may be a key indicator of mechanisms involved in edge sensitivity of forest dependent species in these forests. Our findings indicate that habitat fragmentation and degradation affect Madagascan bird communities and that these processes threaten many species. With continued deforestation and habitat degradation in Madagascar, we predict the further decline of many bird species.     

Boundary processes between a desert sand dune community and an encroaching suburban landscape

In contrast to the body of work in more mesic habitats, few studies have examined boundary processes between natural and anthropogenic desert landscapes. Our research examined processes occurring at boundaries between a desert sand dune community and an encroaching suburban habitat. We measured responses to an anthropogenic boundary by species from multiple trophic levels, and incorporated measures of habitat suitability, and temporal variation, at multiple spatial scales. At an edge versus core habitat scale the only aeolian sand species that demonstrated an unambiguous negative response to the anthropogenic habitat edges was the flat-tailed horned lizard (Phrynosoma mcallii). Conversely loggerhead shrikes (Lanius ludovicianus) demonstrated a positive response to that edge. At a finer scale, species that exhibited a response to a habitat edge within the first 250 m included the horned lizards along with desert kangaroo rats (Dipodomys deserti). The latter species’ response was confined to 25 m from the edge. For the flat-tailed horned lizard, edge effects were measured up to 150 m from the habitat boundary. Three potential causal hypotheses were explored to explain the edge effect on horned lizards: (1) invasions of exotic ant species reducing potential prey for the lizards; (2) road avoidance and road associated mortalities; and (3) predation from a suite of avian predators whose occurrence and abundance may be augmented by resources available in the suburban habitat. We rejected the exotic ant hypothesis due to the absence of exotic ants within the boundary region, and because native ant species (prey for horned lizards) did not show an edge effect. Our data supported the predation and road mortality hypotheses. Mechanisms for regulating population dynamics of desert species are often “bottom-up,” stochastic processes driven by precipitation. The juxtaposition of an anthropogenic edge appears to have created a shift to a “top-down,” predator-mediated dynamic for these lizards.     

Conservation management for Orthoptera in the Dadia reserve, Greece

The diversity patterns, the ecological structure and the typical species of the orthopteran assemblage in the Dadia reserve are investigated. The reserve was designed to protect the black vulture (Aegypius monachus) and other raptors. A total of 39 orthopteran species were found, including Paranocarodes chopardi, a pamphagid species with very restricted distribution. All species can be represented in a network of six complementary habitats, including open oak woodlands, agricultural fields separated with hedges, humid grasslands, as well as serpentine grasslands. The buffer zone of the reserve is far more important for Orthoptera conservation than the core areas, which host most of the black vulture nests. Management focusing on raptors is in general compatible with conservation of Orthoptera. We suggest the maintenance of forest openings in the buffer zone, the maintenance of forest heterogeneity, the enhancement of periodical livestock grazing, and the use of nine indicator species and Paranocarodes chopardi in the reserve monitoring program.     

Bat activity on riparian zones and upper slopes in Australian timber production forests and the effectiveness of riparian buffers

Unlogged buffers are used to ameliorate impacts to riparian areas in timber production forests. One function of these buffers is to protect the biodiversity of riparian areas. We measured bat activity in buffered streams with ultrasonic detectors across four different stream orders in logged, regrowth and mature forests (60 sites). Bat activity, foraging rates and species richness were similar in buffered streams surrounded by logged, regrowth and mature forests, suggesting that riparian areas effectively provide habitat for foraging and commuting bats in selectively logged forests. Vespadelus pumilus was the only species that responded to logging history, with decreased activity in mature forests. We found higher activity on larger rather than smaller order streams, a pattern also not affected by logging history. Bat activity along paired forest trail flyways on upper slopes (60 sites) was measured simultaneously with riparian flyway activity (for a total of 120 sites) to determine the importance of riparian areas relative to other available flyways. Activity was higher on upper slopes than on small streams, but similar to levels on larger streams. Total foraging activity was similar between riparian zones and upper slopes. Upper slopes contained higher species diversity, with Chalinolobus gouldii, Miniopterus schreibersii, Mormopterus norfolkensis, Scotorepens sp., Vespadelus pumilus and, to a lesser extent, Vespadelus darlingtoni detected more often than along streams. Other species (Rhinolophus megaphyllus, Nyctophilus spp. and Miniopterus australis) were not affected by topography. Estimates of total vegetation cover and, in particular, rainforest cover, were negatively associated with bat activity, highlighting the need for management of forest ‘clutter’ in regrowth forests for a suite of bat species. Streams and forest trails provide areas of lower clutter, which assist in maintaining high species diversity in regrowth forests. Our results support the use of riparian buffers, and point to the need for greater recognition of tracks on upper slopes as important habitat.     

Effects of anthropogenic land use on forest birds and butterflies in Subic Bay, Philippines

Despite the loss of 83% of native forests in the Philippines, little is known on the effects of this massive habitat loss and degradation on its forest biotas. This is a cause for concern because of the threat posed to the country’s large number of endemic taxa. To investigate the impacts of anthropogenic disturbance, forest birds and butterflies were surveyed in closed and open canopy forests, as well as suburban, rural and urban areas within the Subic Bay Watershed Reserve and Olongapo City in western Luzon. Measures of forest species richness and population densities for both taxa were similar in the two forest types, but showed different patterns in the other habitats. Indirect gradient analysis showed that forest bird species were positively correlated with vegetation variables (i.e., canopy cover, tree density, height to inversion and ground cover), while forest butterflies were not strongly correlated to any of the measured habitat variables. Community composition of birds in forests was distinct from those in modified habitats, while butterfly communities were more similar. A simulation showed that canopy cover of 60% or higher was required by 24 of the 26 bird species that were sensitive to canopy loss. Endemicity and nesting strata were the significant predictors of vulnerability to habitat disturbance for birds, while endemicity and larval hostplant specificity were significant for butterflies. Both taxa were negatively affected by anthropogenic disturbance but may respond to different components in the habitat (i.e., structure and resources), and thus cannot be used as surrogates of each other. Conservation of forests with contiguous canopy cover should be prioritized, and more ecological research is needed to improve the knowledge on the effects of disturbance on Philippine biodiversity.     

Post-fledging dispersal, habitat use, and survival of Sprague’s pipits: Are planted grasslands a good substitute for native?

Loss and degradation of native grasslands on the North American landscape are some of the key factors influencing population declines of grassland songbirds. It is unclear what role anthropogenic grasslands play in the conservation of grassland specialists and whether demographic parameters of grassland songbirds differ between anthropogenic and native grasslands. Furthermore, there has been little research examining the overlap (or lack thereof) between nesting and post-fledging habitat. We initiated a radio-telemetry study from 2004 to 2008 on dispersal, microhabitat use, and survival of juvenile Sprague’s pipits (Anthus spragueii), a threatened grassland-obligate songbird, in native pastures and fields planted with exotic species (planted grasslands). Dispersal distance was greater in planted compared to native grasslands, but appeared to be constrained to natal fields up to 26-d post-fledging. Pipits used microhabitats in planted grasslands with vegetation that was on average 11 cm taller than used locations in native pastures, possibly due to the rapid growth of planted vegetation by the time individuals fledged. Individuals that were reared in planted grasslands had consistently lower daily survival rates compared to those in native pastures. Our observation that young birds rarely left their natal field suggests that conserving nesting habitat in native pastures would be an effective management strategy for this species. However, our results suggest that planted grasslands may act as population sinks given the lower survival of juvenile pipits reared in planted fields in our region. Demographic studies during the post-fledging period are essential to determine the conservation value of anthropogenic grasslands for North American songbirds.     

Plant communities at the periphery of the Atlantic rain forest: Rare-species bias and its risks for conservation

Initiatives that establish species rarity as an indicator of conservation priority might be biased if they disregard important evolutionary and adaptive processes taking place in lower diversity communities and ecotones. Conservation policies regarding the Atlantic forest strongly emphasize the core formation (i.e. the rainforest stricto sensu) rather than the marginal habitats (e.g. restingas, swamps, and high altitude campos) and species that are rare/endemic. To discuss this issue I revisit a hypothesis I have forwarded in 2002 that postulates that plant colonization of habitats marginal to the Atlantic rain forests of the State of Rio de Janeiro was largely related to terrestrial nurse plants that originally, in the rainforest habitat, were canopy plants such as epiphytes or hemi-epiphytes. Adaptations to water and nutrient restrictions, typical of life in the canopy, granted success to such plants upon migration to sandy, swampy or rocky substrates in neighbouring areas. Many such species, then, behaved as nurse plants and favoured colonization of these more extreme habitats by a number of other rainforest species. I now review recent evidence that corroborate this hypothesis, while examining the nature of such nurse plants. In all marginal habitats, nurse plants are often highly abundant locally and have high ecophysiological vigour, while both widespread and endemic species are found among them. Thus, nursing effect, local abundance, and ecophysiological performance are not related to species geographic distribution or to their spectrum of habitat preference. Paradoxically, several abundant nurse plant species have low Darwinian fitness. These studies provoke two reflections. First, the Atlantic forest sensu lato, i.e. the core formation plus the peripheral ones, should be treated collectively as a biodiversity hotspot, rather than the core rainforest formation alone. Second, widespread or common species play important functional roles in such marginal habitats and, despite their ubiquity, ecologically they might be less fit than rare/endemic ones at the local level due, for instance, to current constraints to sexual reproduction. Thus, they should also be targeted as conservation priorities.     

Land use and habitat gradients determine bird community diversity and abundance in suburban, rural and reserve landscapes of Minnesota, USA

Bird species’ community responses to land use in the suburbanizing Twin Cities, Minnesota, USA, were contrasted among reserves, rural lands, and suburbs. For each land use type, bird composition, diversity, and abundance were recorded for 2 years in ≈99 plots in three sampling units (each ≈4500 ha). A habitat gradient defined by canopy structure (grasslands to savannas to forests) was influenced by land use, so ≈300 plots were used to characterize simultaneous variation in bird communities along land use and habitat gradients. At broad scales (aggregate of 33 plots covering ≈4500 ha) suburbs supported the lowest bird richness and diversity and rural landscapes the most, with reserves slightly below rural. Although reserves were like rural lands in diversity of bird communities, they supported more species of conservation concern, particularly of grasslands and savannas. Differences among land use types varied with habitat structure. Suburbs, rural lands, and reserves had similar forest bird communities, but differed in grassland and savanna bird communities. The extensive rural forests are important for the region’s forest birds. Suburban grasslands and savannas had low shrub abundance, low native bird richness and high non-native bird richness and abundance. However, total bird richness and diversity were as high in suburban as in rural and reserve plots because high native richness in suburban forests and high non-native species richness in suburban grasslands and savannas compensated for lower native richness in suburban grasslands and savannas. Bird conservation here and in the Midwest USA should protect rural forests, expand grasslands and savannas in reserves, and improve habitat quality overall.     

Tolerance of frugivorous birds to habitat disturbance in a tropical cloud forest

In view of the continued decline in tropical forest cover around the globe, forest restoration has become a key tool in tropical rainforest conservation. One of the main - and least expensive - restoration strategies is natural forest regeneration. By aiding forest seed influx both into disturbed and undisturbed habitats, frugivorous birds facilitate forest regeneration. This study focuses on the tolerance of a frugivorous bird community to anthropogenic habitat disturbance within the broader context of natural forest regeneration with conservation purposes. It was carried out in the tropical cloud forest of Costa Rica’s Talamanca Mountains. Bird community response and tolerance to habitat disturbance was assessed by comparing bird presence and densities along a disturbance gradient, ranging from open pastures to closed mature forests. Birds were censused along nine transects applying the variable width line transect procedure. Forty relevant frugivorous bird species were observed during 102 h of survey time. Densities were calculated for 33 species; nine species responded negatively to increasing level of disturbance and nine others positively. Results indicate that large frugivores are generally moderately tolerant to intermediate, but intolerant to severe habitat disturbance, and that tolerance is often higher for medium and small frugivores. It appears that moderately disturbed habitats in tropical cloud forests are highly suitable for restoration through natural regeneration aided by frugivorous birds. Due to a lack of large forest seed dispersers, severely disturbed habitats appear less suitable.     

Edge effects on nesting success of cavity-nesting birds in fragmented forests

Forest fragmentation leads to the creation of isolated forest patches and habitat edges with subsequent impact on forest-interior bird species. Although the effects of fragmentation and edge on avian nesting success are well documented for open cup-nesting species in eastern deciduous forests in North America, it is unclear whether these effects are common for all birds nesting in predominantly forested landscapes. In particular, edge effects on nesting success of cavity-nesting birds are poorly understood. Using natural cavity nests, we examined nesting success of four species of cavity-nesting birds (two nonexcavators and two excavators), the yellow-rumped flycatcher (Ficedula zanthopygia), the great tit (Parus major), the great spotted woodpecker (Picoides major), and the grey-faced woodpecker (Picus canus) in relation to forest edges in Zuojia Nature Reserve, Jilin province, northeastern China. Our primary objective was to assess whether distance to the edge of agricultural lands was related to nesting success for cavity-nesting birds in fragmented forests. A total of 439 natural cavity nests of the four species were located and monitored during four breeding seasons. Probability of nest success was influenced by distance to forest edge for nonexcavators, but not for excavators. The rate of nesting success of the two nonexcavators, yellow-rumped flycatcher and the great tit, increased with distance from the edges. For all cavity nests, nesting success was 0.43 at 0-100 m, 0.56 at 101-200 m, 0.68 at 201-300 m, 0.61 at 301-400 m, 0.77 at 401-500 m from the edges. Nesting success ranged from 0.57 for the yellow-rumped flycatcher to 0.89 for the Grey-faced Woodpecker. Failed nests were often occupied by nest-site competitors (accounting for 68%). However, predation only accounted for 20% of all nest failures. Our results suggest that negative edge effects do exist for some cavity-nesting birds, especially for nonexcavator species.     

Main environmental drivers of abundance, diversity and community structure of comammox Nitrospira in paddy soils

The recently discovered complete ammonia oxidizers comammox Nitrospira contain clades A and B that can establish an independent one-step nitrification process; however, little is known about their environmental drivers or habitat distributions in agricultural soils. Previous studies on comammox Nitrospira in paddy soils have mainly focused on small-scale samples, and there is a lack of multisite research on comammox Nitrospira in paddy soils. In this study, we conducted a survey of 36 paddy soils to understand the community structure, abundance, and diversity of comammox Nitrospira and the degree to which they are affected by environmental factors at a large scale. Comammox Nitrospira were found to be widely distributed among the paddy soils. The abundance of comammox Nitrospira clade A was mostly lower than that of clade B, whereas its diversity was mostly higher than that of clade B. Correlation analysis showed that multiple factors affected (P < 0.05) the abundance of comammox Nitrospira, including soil pH, organic matter, total carbon, and total nitrogen, latitude, mean annual temperature, and mean annual precipitation. Moreover, there was a clear relationship between the comammox Nitrospira community and habitat, indicating that some amplicon sequence variants (ASVs) had a unique dominant position in specific habitats. Phylogenetic analysis showed that the ASVs of comammox Nitrospira clade A clustered with the known sequences in the paddy soils and were significantly different from the known sequences in other habitats, which may be related to the unique paddy field habitat. In contrast, comammox Nitrospira clade B showed no clear habitat dependence. These results support the wide distribution and high abundance of comammox Nitrospira in paddy soils and provide novel insights into nitrogen cycling and nutrient management in agricultural ecosystems.     

The influence of disturbance and habitat on the presence of non-native plant species along transport corridors

The impact from transportation corridors on surrounding habitat often reaches far beyond the edge of the corridor. The altered disturbance regime in plant communities along corridor edges and vehicle traffic facilitate the spread and establishment of invasive non-native plant species. We compared the frequency of non-native plant species along highways and railways and the ability of these species to invade grasslands and dense forests along these corridors. We measured the frequency of several non-native plant species along transects 0-150 m from the edge of highways and railways in grasslands and forests, as well as at control sites away from corridors. Both transportation corridors had higher frequency of non-native species than respective control sites. Grasslands had higher frequency of non-native species than forested habitats, but the frequency did not differ between the highways and the railways. The frequency of non-native species in grasslands along highways and railways was higher than at grassland control sites up to 150 m from the corridor edge, whereas the frequency in forested habitats along corridors was higher than at forested control sites up to only 10 m from the corridor edge. There was a significant decrease in the frequency of non-native species with increasing distance from both corridors in the forest, while grasslands showed no significant change in non-native species frequency with distance from corridors. This suggests that corridor edges and grassland habitats act as microhabitats for non-native species and are more prone to invasion than forests, especially if disturbed. Our results emphasize the importance of minimizing the disturbance of adjacent plant communities along highways and railways during construction and maintenance, particularly in grassland habitats and in areas sensitive to additional fragmentation and habitat loss.