Woodland Habitats Research Articles

Loop-migration and non-breeding locations of British breeding Wood Warblers Phylloscopus sibilatrix

ABSTRACT Capsule: British breeding Wood Warblers Phylloscopus sibilatrix show a clockwise loop migration incorporating stops in southern Europe, the Sahel, and the humid forest zone of West Africa. Aims: To determine autumn and spring migration routes, the location and duration of stopover sites on migration, and the location of non-breeding areas of British breeding Wood Warblers. Methods: In 2016 and 2018 we deployed geolocators to male Wood Warblers on Dartmoor, Devon, and in the New Forest, Hampshire. We retrieved four geolocators from returning birds in 2017, 2019, and 2020. Results: Male Wood Warblers departed breeding sites in late July and stopped for most of August in central southern Europe, crossed the Sahara by a non-stop night and day flight immediately followed by a short stop, and then migrated west to a longer stopover in the Sahel. Final non-breeding destinations were in an area of West Africa covering Guinea, Sierra Leone, and Liberia. Two were tracked on spring migration, again crossing the Sahara via a non-stop flight before migrating through Western Europe to complete a clockwise loop migration back to Britain. Conclusion: All tracked Wood Warblers used stopovers for at least three weeks in three distinct regions, in central southern Europe, in the Sahel, and in the humid zone of West Africa. Although the limitations of geolocation prevent matching locations with habitat, these regions are broadly characterized by distinct forest or woodland habitat types, which differ from breeding habitat. All four tracks showed similar patterns in route, stopover behaviour, and timings, suggesting they may be representative of males in these breeding populations, and potentially of other British and western European Wood Warbler populations.

Overland flow velocity and soil properties in established semi‐natural woodland and wood pasture in an upland catchment

AbstractManagement of upland land‐use has considerable potential for mitigating flood risk by increasing topsoil storage and slowing overland flow. Recent work has highlighted the potential for vegetation to impact the velocity of saturation‐excess overland flow. Woodland creation is widely proposed for Natural Flood Management (NFM), but data on saturation‐excess overland flow in woodland habitats is lacking. Here we measure soil properties and overland flow velocities in established broadleaf woodland and wood pasture with an understorey dominated by either grass or bracken. We show that wood pasture dominated by bracken has overland flow velocity 12–20% lower than established broadleaf woodland and 19–27% lower than grass‐dominated wood pasture. Established woodland soils exhibited eight times higher saturated hydraulic conductivity than bracken‐dominated wood pasture and 80 times higher than grass‐dominated wood pasture. We conclude that upland habitats can be managed to reduce flood risk, first by storing storm water in the soil and then by reducing overland flow velocity through rough surface vegetation. These factors combine to reduce floods by delaying the onset of overland flow runoff and slowing its delivery to streams. It is clear than Manning's n is far from constant in these shallow overland flows, the development of overland flow datasets is, therefore, also beneficial for improving the theory and practice of hillslope rainfall‐runoff modelling.

Diet DNA reveals novel African Forest elephant ecology on the grasslands of the Congo Basin

AbstractElephants are essential ecological engineers, creating and maintaining landscape structure and ecosystem function. The recently distinguished and critically endangered forest elephant is currently classified as a selective, non‐destructive frugivorous browser that maintains forest diversity, while the savanna elephant is a mixed feeder, often pushing over trees while maintaining grasslands. The presence and diets of forest elephants on grasslands and the potential maintenance of these systems remain largely unexplored. In the ecotone between the Guinea‐Congolian forest and Sudanian‐Guinean savanna ecosystems in Garamba National Park, DRC, we investigated forest elephant diet selection as a function of sex, age, and habitat using diet DNA (dDNA) metabarcoding of non‐invasively collected dung. GPS collar data were used to determine annual habitat use. Dietary niche partitioning was assessed among megaherbivores in the grasslands. Fecal samples represented the diet of individuals within each habitat, providing valuable insight into the plant biodiversity. Ecological patterns of diet were also revealed using a taxonomically free exact sequence variance approach, highlighting useability in a poorly characterized region. In the early wet season, these typically frugivorous forest elephants were consuming mostly grasses in both the woodland and grassland habitats and showing no sexual dimorphism in diet selection when in the same habitats. However, males were greater risk‐takers, entering the human‐altered landscape to forage on fruit. The forest elephants play a distinctive role within this tropical grassland when compared to other megaherbivores and utilize the unique ecosystem throughout the year. This elephant population is exhibiting behavioral plasticity and shifting their gardening efforts to a novel resource in the grasslands as opposed to their standard role in the forests, which is key to understanding their impact as ecosystem drivers within this landscape. This shift in behavior may result in this recovering elephant population playing a functional role in the restoration and maintenance of these grasslands.

Native to Nemesis: a cultural and environmental history of the Noisy Miner 1788 - 2019

ABSTRACT 1878: “…gallant little birds” (Wagga Wagga Advertiser) 1915: “… the carol of the magpie is eclipsed by the song of the miner” (Emu) 2004: “…the mafia of the bird world” (Australian Broadcasting Corporation) 2015: “I hate those f***in things” (RedditAustralia) Through the 19th Century and the first half of the 20th Century, notwithstanding its role as an agricultural pest, the Noisy Miner Manorina melanocephala was considered with affection by colonial society. The species’ reputation has been severely damaged in recent decades, however, on account of its violent tendencies towards smaller woodland birds, including many of conservation concern. Aggressive exclusion of small woodland birds from potential woodland habitat by Noisy Miners was declared a Key Threatening Process under federal conservation legislation in 2014. Given that Noisy Miners, other woodland birds, and the post-ice age woodland environment have been co-evolving for at least 10 000 years, how did the natural competitive behaviour of Noisy Miners become an ecological problem? In this paper I review historical references to Noisy Miners and current research on the ecology of the species to construct a trajectory of change. Culturally, these changes include a shift in attitudes to the species from agricultural pest and popular native bird to a vilified, “overabundant” native species and nemesis of small woodland birds. Ecologically, changes have included an expansion in distribution and abundance of Noisy Miners. This has led to an increase in scale of the effects of Noisy Miner aggression on small woodland birds. The historical record contains many references to Noisy Miner aggression against other species, the first appearing within four years of the arrival of the First Fleet in 1788. Evidence that such aggression could affect the abundance and distribution of small woodland birds, however, appears only in the period after World War II. The changing ecological role of Noisy Miners, and the associated changes in cultural attitude to the species, appear linked to the loss, fragmentation and degradation of native woodland in eastern Australia since the introduction of European agriculture and urbanization. In particular, the change in ecological role of the Noisy Miner appears to be linked to the accelerated rates of deforestation in the post-war period. Such broadscale habitat modification has both benefitted Noisy Miners and exacerbated declines in woodland-dependent small birds.

Seed traits and fate support probable primary dispersal of a native hemi-parasitic vine Cassytha pubescens (Lauraceae) by Isoodon obesulus, an endangered marsupial, in southern Australia

ABSTRACT Consumption of seeds by fruit-eating animals is one of the most effective dispersal mechanisms for plants, yet little is known about dispersal by marsupial vectors. In the face of habitat fragmentation and the recent extinction or decline of many marsupial species in southern Australia, addressing knowledge gaps on vertebrate vectors is critical to determine deficiencies in seed dispersal. Here we examine one potential dispersal vector for the seeds of Cassytha pubescens, a native hemi-parasitic vine that contributes to vegetation complexity within many woodland habitats in southern Australia that are threatened by fragmentation. To determine the potential dispersal role of mammals for Cassytha pubescens within southern Australian woodlands, we collected and examined 46 scat samples from the omnivorous, nationally endangered southern brown bandicoot, Isoodon obesulus, over two fruiting (summer) seasons. Of the 46 scats, five had up to six seemingly undigested seeds of C. pubescens, indicating that I. obesulus consumes the fruits and may act as a disperser for this vine. Our findings improve understanding of the role of marsupials like bandicoots in dispersing native plant seed and may help to inform conservation management priorities to protect ecosystem function more effectively in fragmented woodlands threatened by loss of vertebrate seed vectors.

The prevalence and distribution of Anaplasma phagocytophilum genotypes in Ixodes ricinus nymphs collected from farm- and woodland sites in Ireland

Despite the economic importance of grass-based livestock production in Ireland and the fact that many veterinarians and farmers regard tickborne fever (TBF) as an increasingly important disease, especially in sheep, little is currently known about the prevalence and genetic diversity of its causative agent, Anaplasma phagocytophilum. In the present study, 1376 nymphal Ixodes ricinus ticks collected from woodland, farmland, bog and limestone pavement habitats were screened for A. phagocytophilum using TaqMan PCR. Positive samples were further analysed by conventional nested PCR targeting the 16S rRNA, msp4 and groEL loci.Overall 4.5% I. ricinus nymphs were found to be infected. The genetic heterogeneity was comparable to that reported elsewhere in Europe, with greater genetic diversity of 16S variants in ticks collected from farmland than from woodland. All isolates belonged to groEL ecotype I indicating that rodents and birds do not contribute to the epidemiology of tickborne fever in Ireland. In the 16S and groEL loci, a number of the Irish isolates matched European sequences from humans, horses and dogs. The 16S sequences that were identical to human isolates from Europe also matched Ap-ha, the most common human pathogenic strain in the USA. Three isolates also matched published sequences from horses in the msp4 locus. No isolate matched human, equine and canine sequences in all 3 loci. Our results represent the first molecular characterization of Irish A. phagocytophilum isolates.

Mesocarnivore Distribution along Gradients of Anthropogenic Disturbance in Mediterranean Landscapes

Wildfires are important sources of landscape change in Mediterranean environments, creating large patches of low-growth natural habitats (i.e., scrublands) inside protected areas, whereas woodland patches remain mostly near well protected human settlements. Landscape patterns resulting from these gradients influence habitat suitability for mesocarnivores regarding food and shelter. In winter and summer 2019, we sampled 16 independent line-transects with four camera traps each (64 cameras overall), covering the main habitats of the study area (woodlands, scrublands, and crops). Cameras were baited to compensate for the low detectability of target species, and mesocarnivore contacts were analysed by means of GLMMs and occupancy models. Our results showed a positive and stronger association of wild species with woodland habitats, despite the low proportion of habitat available, higher presence of competitors (other mesocarnivores), and potential predators (human pets, i.e., dogs), and low natural prey availability than in scrubland (i.e., small mammals). However, mesocarnivores will find protection against predators and resting sites in forests as well as other food opportunities in crops and urban areas, despite the possible interference with humans and their pets. Potential cascading effects linked to ecological roles of Mediterranean mesocarnivores on the succession of Mediterranean landscapes would imply longer-term effects of human disturbance on landscape trends.

Local habitat characteristics determine butterfly diversity and community structure in a threatened Kihansi gorge forest, Southern Udzungwa Mountains, Tanzania

BackgroundMany species inhabiting Kihansi gorge ecosystem in Southern Udzungwa Mountains, Tanzania are threatened with extinction due to habitat loss caused by constructed hydropower plant that diverted over 90% the water off the Kihansi River. Understanding ecological correlates and structure of an animal community in perturbed ecosystems is an important way to enhancing species conservation particularly in this system, where several species are already threatened with extinction. This study assessed influences of local habitat characteristics on the butterfly abundance, species richness and diversity and examined how the butterfly community structures across three structurally heterogeneous habitats in the Kihansi gorge forest. Butterfly abundance data were collected using baited traps and measured environmental variables in the field, where trapping occurred. To understand the diversity and butterfly richness, these parameters were computed under Primer software. Non-metric multidimensional scaling and analysis of community similarity were used to analyse the butterfly community structure. Furthermore, the generalized linear models (GLM) were used to assess how the measured variables explained observed species diversity, abundance, and richness.ResultsIn total, 72 species of butterfly in five families were recorded. Butterfly species diversity and richness did not vary across the habitat types or elevation gradient but showed strong correlation with some habitat characteristics. In addition, there was evidence of butterfly communities structuring into distinct groups that showed greater separation associated with the habitat characteristics they utilise. Furthermore, across the study area, butterfly species diversity increased significantly in high canopy and in trees with smaller DBH and at lower ground cover. Similarly, abundance significantly increased in the woodland and wooded grassland habitats, where there was high canopy and where tree density was high. Furthermore, butterfly species richness was strongly positively associated with high canopy cover and mostly increased in sites closer to water source.ConclusionFirst, this study shows strong positive correlation between the habitat characteristics and butterfly species and community structure, suggesting strongly that maintaining habitat quality should be a priority in conserving the butterfly communities in Kihansi. Second, conservation of environmental disturbance indicator butterfly taxa which are also endemic and rare is worthy of concern under the ongoing human-induced threats in the area. It is appropriate time that the Tanzania government should declare the Kihansi gorge forest among existing protected areas to secure effective conservation of biological diversity in this threatened ecosystem. Third, the ants–butterfly symbionts and their links to the potential lichen depletion are still unclear, and thus future research should explore the trophic cascades of depleting habitat quality on the endemic and rare butterfly species in the Kihansi gorge.

Avian Communities of Alatish National Park, Ethiopia

Alatish National Park, which is located in the Amhara National Regional State at the border with the Republic of Sudan, is rich in its avian resources. To study the park’s avian communities, the study area was classified based on its vegetation structures into riverine woodland, wooded grassland, woodland, and bamboo woodland. Data were collected from July 2017 to April 2018 using line transect and point count methods. As a result, 132 species of birds belonging to 18 orders and 55 families were identified. The highest species diversities during the wet (H’ = 3.53) and dry (H’ = 3.55) seasons were recorded in the riverine woodland habitat. Species evenness was also the highest during the wet (E = 0.79) and dry (E = 0.77) seasons in the riverine woodland habitat. The bamboo woodland habitat harboured the lowest species diversity during the wet (H’ = 2.81) and dry (H’ = 2.45) seasons. More species similarity (SI = 0.90) was recorded between wooded grassland and bamboo woodland habitats during the dry season. Relative abundance of birds among the different species showed significant differences (F131, 1452 = 2.94,P<0.05), and most birds in the area were identified as uncommon species. Forest fire, logging, and overgrazing by cattle have significantly contributed to habitat destruction in the park which might act as the cause for reduction in avian diversity. Therefore, appropriate conservation strategies should be designed and implemented to minimize avian habitat destruction due to various anthropogenic activities within the park.

Stable isotope signals provide seasonal climatic markers for moss functional groups.

Living moss biomass and archival peat deposits represent key indicators of present and past climatic conditions, but prediction of future climatic impacts requires appropriate marker species to be characterized under a range of contemporary conditions. Stable isotope signals in high latitude moss deposits offer potential climatic proxies. Seasonal changes in δ13C and δ18O of organic material (cellulose) in representative functional groups, and associated photosynthetic activity (as chlorophyll fluorescence) have been compared across East Anglia, UK, as a function of tissue water content. Representative species from contrasting acid bog, heathland, and fen woodland habitats were selected for monthly sampling of recent growth tissues between spring 2017 and autumn 2018, with isotopic signals in purified cellulose compared with tissue water, precipitation, and nearby groundwater signals. Sphagnum and Polytrichum groups, which tend to dominate peat formation, provided contrasting and complementary indicators of seasonal variations in carbon assimilation. Cellulose δ18O signals from Sphagnum spp. demonstrate seasonal variations in source precipitation inputs; carbon isotope signals in Polytrichum spp. indicate evaporative demand and photosynthetic limitation.

Conservation potential of semi-natural habitats for birds in intensively-used agricultural landscapes

Agricultural intensification resulted in substantial loss of farmland biodiversity. Semi-natural habitats may be viewed as potential buffers of these adverse impacts, but a rigorous assessment of their capacity for supporting farmland biodiversity is lacking. In this study, we explored conservation potential of two different types of semi-natural habitats for birds in intensively-used agricultural landscapes – farmland hedges (i.e., linear strips of shrubby and tree vegetation) and open scrubland (i.e., scattered shrubs and abandoned orchards). Specifically, we tested whether the abundance and species richness of birds differ between these habitats considering various species traits, such as habitat affinity (i.e., forest, farmland and urban species), diet specialization (i.e., animal eaters, plant eaters, and omnivores) and conservation status (Species of European Conservation Concern). We found that open scrubland hosted on average 37.9 bird species and 122.6 individuals per 1 km2 of the transect, whereas farmland hedges hosted only 19 species and 61.8 individuals per 1 km2 of the transect. However, results have substantially changed if we considered the area of suitable habitat into account. More specifically, open scrubland hosted more bird species and individuals when we considered open habitat species and the area of open habitats, whereas farmland hedges had higher species diversity and individuals of woodland bird species when we considered the area of woodland habitats. Similarly, analyses of habitat affiliations of individual species corresponded to the whole-community patterns; and revealed that several woodland bird species were mainly associated with farmland hedges (e.g., Chaffinch Fringilla coelebs, Common Nightingale Luscinia megarhynchos and Blackcap Sylvia atricapilla), whereas the open scrubland was preferred by open habitat bird species (e.g., Corn Bunting Emberiza calandra, Quail Coturnix coturnix and Skylark Alauda arvensis). These results demonstrate that semi-natural habitats, both open scrubland and farmland hedges, have large potential for promotion and conservation of bird communities within intensively used agricultural landscapes, as both may have represented suitable habitats for species with different ecological requirements. Therefore, management measures focused on the enlargement of the area of these habitats, in combination with suitable management (e.g., regulating the progress of natural succession in open scrubland; increasing structural diversity of existing farmland hedges), may substantially contribute to bird conservation within agricultural landscapes.

Spatiotemporal Distribution of Two Euschistus spp. Stink Bugs (Hemiptera: Pentatomidae) in Southeastern Farmscapes.

Stink bugs (Hemiptera: Pentatomidae) are ubiquitous, cryptic, phytophagous pests that are found in many crops. In agroecosystems, individuals disperse from adjacent noncrop hosts and tend to aggregate or cluster within fields. In this study, we characterized the distribution of Euschistus servus (Say) and Euschistus tristigmus (Say) (Hemiptera: Pentatomidae) over 2 yr at three southeastern United States farmscapes. Stink bugs were captured in pheromone-baited traps, and Spatial Analysis by Distance Indices (SADIE) used to identify the location of significant aggregations by habitat type and season. Euschistus servus adults were more likely to be captured in pecan orchards, cotton, other crops, or unmanaged habitats than in woodland habitats. Significant aggregations of E. servus were detected in a variety of habitats including pecan, corn, cotton, peanut, and tobacco, as well as fallow and hay fields, pastures, and hedgerows. Fewer adult E. tristigmus were captured than E. servus adults, and E. tristigmus adults were typically trapped and aggregated in woodland habitats. The resulting data provide an important understanding regarding the seasonal movement and relative abundance levels of stink bug populations, which are critical to the development of integrated pest management strategies.

Impacts of ‘Curiosity’ baiting on feral cat populations in woodland habitats of Kangaroo Island, South Australia

Context Across Australia, feral cat (Felis catus) control and eradication programs are conducted to conserve threatened and vulnerable species. Controlling feral cats effectively at a landscape scale, particularly in remote woodland habitats, remains a significant challenge. Unfortunately, some standard feral cat control methods, such as shooting and cage trapping, require road access. Poison baiting is one of the few methods available to control feral cat populations in remote and inaccessable areas. Aims We aimed to examine the impact of a Curiosity® (Scientec Research PTY LTD, Melbourne, Australia) baiting program on the feral cat population found in continuous woodland habitat of the Dudley Peninsula, on Kangaroo Island, South Australia. Methods The density of cats was monitored using camera traps set up across both treatment and control sites using a before–after control–impact approach. Feral cat density was calculated using a spatially explicit capture–recapture framework. In addition, 14 feral cats were GPS collared at the treatment site, and their status and location, before and after baiting, was monitored. Key results At the treatment site after baiting, feral cat density fell from 1.18 ± 0.51 to 0.58 ± 0.22 cats km−2. In total, 14 feral cats were GPS collared, and of those, eight were detected within the treatment zone during and after bait deployment. Six of those eight cats died shortly after baiting, likely from bait consumption. A new individual cat was detected in the treatment zone within 10 days of baiting, and within 20 days, four new individuals were detected. Both before and after baiting, the number of feral cat detections was highest on roads, suggesting cat recolonisation of baited areas may be assisted by roads. Conclusions Curiosity baiting was found to be an effective method for reducing the density of feral cats in continuous woodland habitats of Kangaroo Island. Roads may act as access routes aiding cat recolonisation. Implications Curiosity baiting programs on Kangaroo Island (and elsewhere) would benefit from incorporating follow-up control, particularly along roads, to target feral cats re-colonising the area.

Plastic is a Widely Used and Preferentially Chosen Nest Material for Birds in Rural Woodland Habitats

Plastic is a Widely Used and Preferentially Chosen Nest Material for Birds in Rural Woodland Habitats

Seasonal variation of non-volant small mammals in Gibe Sheleko national park, Southwestern Ethiopia

The species composition and abundance of small mammals can vary within space and time. The main objective of this study was to assess seasonal variation of non-volant small mammals from randomly selected Acacia woodland, bushland, farmland, grassland, riverine forest and wooded grassland habitats in Gibe Sheleko National Park, southwestern Ethiopia. Data were collected using 49 Sharman live traps in 70 x 70 m sized square girds from December, 2018 to August, 2020. Capture mark recapture technique was applied to estimate population size of the existing small mammals and the data were analyzed using a chi-square test. A total of 1160 individual small mammals belonging to 10 species and 2 families were recorded. Three non-captured species: Hystrix cristata, Xerus rutilus and Tachyoryctes splendens were also identified. There was a significant (χ2= 31.12, df = 1, P < 0.05) difference in the total abundance of small mammals between seasons. Of the total individuals captured, 675(58.19%) were trapped during the wet season while 485(41.81%) individuals were during the dry season. Significant seasonal variation was also observed in the total abundance of both sexes, i e. males (χ2= 11.99, df = 1, P < 0.05) and females (χ2= 20.24, df = 1, P < 0.05). Among age groups, significant statistical seasonal variation was shown in adults (χ2=15.14, df = 1, P < 0.05) and young (χ2=44.61, df = 1, P < 0.05) but not significant in sub-adults (χ2=0.75, df = 1, P >0.05). The identified small mammals exhibited seasonal changes in their abundance associated with changes in climatic and environmental conditions. However, a long-term and annual based study is required to see the overall dynamics of existing small mammals.

Native seed dispersal by rodents is negatively influenced by an invasive shrub

Refuge–mediated apparent competition is the mechanism by which invasive plants increase pressure on native plants by providing refuge for generalist consumers. In the UK, the invasive Rhododendron ponticum does not provide food for generalist seed consumers like rodents, but evergreen canopy provides refuge from rodent predators, and predation and pilferage risk are key factors affecting rodent foraging and caching behaviour. Here we used a seed removal/ seed fate experiment to understand how invasion by an evergreen shrub can alter seed dispersal, seed fate and early recruitment of native trees. We used seeds of four species, small and wind–dispersed (sycamore maple Acer pseudoplatanus and European ash Fraxinus excelsior) and large and animal–dispersed (pedunculate oak Quercus robur and common hazel Corylus avellana), and monitored seed predation and caching in open woodland, edge habitats, and under Rhododendron. In the open woodland, wind–dispersed seeds had a higher probability of being eaten in situ than cached seeds, while the opposite occurred with animal–dispersed seeds. The latter were removed from the open woodland and edge habitats and cached under Rhododendron. This pattern was expected if predation risk was the main factor influencing the decision to eat or to cach a seed. Enhanced dispersal towards Rhododendron cover did not increase the prospects for seed survival, as density of hazel and oak saplings under its cover was close to zero as compared to open woodland, possibly due to increased cache pilferage or low seedling survival under dense shade, or both. Enhanced seed predation of ash and sycamore seeds close to Rhododendron cover also decreased recruitment of these trees. Rhododendron patches biased rodent foraging behaviour towards the negative (net predation) side of the conditional rodent / tree interaction. This effect will potentially impact native woodland regeneration and further facilitate Rhododendron spread due to refuge–mediated apparent competition.

Agroecosystem landscape diversity shapes wild bee communities independent of managed honey bee presence

Large scale agricultural production can lead to a reduction in availability of habitat used by wild bees for nesting and forage and has been implicated in worldwide bee population declines. There is growing concern that further declines in wild bee populations will occur because of continued transformations of natural or seminatural landscapes into crop monocultures. Managed honey bees, often used for pollination services in agricultural systems, can compete with wild bees and are hypothesized to negatively affect their communities. Although the response of wild bees to both agriculture and honey bees (i.e., apiculture) has been studied, the relative importance of each and their potential interactions on wild bee communities are not well understood. To forecast the extent to which landscape simplification can affect wild bees and to better understand whether honey bee presence in an already disturbed landscape might further exacerbate declines, we conducted a replicated, longitudinal assessment of wild bee community richness and richness of functional guilds (e.g., floral specificity and nesting preference) in an intensively farmed region of the United States where much of the landscape is devoted to monoculture annual crop (maize and soybean) production and managed honey bee colonies co-occur. The presence of a small apiary (4 colonies) had no immediate effect on wild bee richness, suggesting honey beekeeping may not always negatively impact wild bees. Rather, landscape composition analysis showed strong responses of wild bees to land use, with communities being less speciose in landscapes with high proportions of crop production. The availability of woodland and grassland habitat, especially at the local scale (<800 m), was associated with the greatest increase in bee richness especially for rarer aboveground nesting and floral specialist species. These data suggest large scale monocultures have a greater impact on bee communities than the presence of small apiaries. The results of this research provide important information on possible solutions in agroecosystem management to support increased bee diversity where annual crop production and apiculture are practiced. Namely, mitigation of wild bee declines in such agroecosystems may benefit more from the re-integration of landscape biodiversity, with priority on the re-introduction of perennial vegetation, like that found in woodland and grassland habitats, than the restriction of honey bee apiculture. Data AvailabilityData will be archived through Iowa State Universities digital data repository.

Persistence of Seed Dispersal in Agroecosystems: Effects of Landscape Modification and Intensive Soil Management Practices in Avian Frugivores, Frugivory and Seed Deposition in Olive Croplands

Farming impacts animal-mediated seed dispersal through mechanisms operating on at least two spatial scales. First, at the landscape scale, through habitat loss and land conversion to agriculture/livestock grazing, and second, at the farm scale, via a local intensification of agricultural practices. These two scales of farming impact seed dispersal function but have rarely been integrated. In particular, studies evaluating the effect of agriculture on the seed dispersal function of frugivorous birds in Mediterranean ecosystems are lacking. This study evaluates the role of landscape transformation, from fruit-rich woodland habitats to olive grove landscapes, together with local intensive practices of soil management on the persistence of the seed dispersal function for Mediterranean fleshy-fruited plants in olive landscapes of south Spain. We used bird censuses, mist-nets, and seed traps to characterize avian frugivore assemblages, frugivory, and seed deposition in the seminatural woodland habitat (SNWH) patches and olive fields of 40 olives farms spanning 20 localities distributed across the whole range of olive cultivation in Andalusia (southern Spain). We found that despite the remarkable dispersal function of olive grove landscapes, avian frugivore abundance and diversity, frugivory, and seed arrival decreased in olive fields compared to SNWH patches. Likewise, SNWH cover loss and/or olive growing expansion decreased avian frugivory and seed arrival. Interestingly, the habitat effects in the olive farms often depended on the landscape context. In particular, less diverse fruit-eating bird assemblages pooled in SNWH patches as olive grove cover increased or SNWH decreased in the landscape, while remaining relatively invariant in the olive fields. Finally, compared to conventional intensive agriculture, low-intensity management increased frugivory and seed deposition. We conclude that olive fields are less permeable to frugivores than expected due to the agroforest-like nature of these landscapes and that the presence of SNWH patches is crucial for the maintenance of frugivory and seed dispersal in agricultural landscapes. These results evidence that woodland habitat loss by olive expansion and intensive practices seriously threaten the dispersal service in olive-dominated landscapes. Maintenance, restoration, and promotion of woodland patches should be prioritized for the conservation of seed dispersal service and for enhancing the functional connectivity in human-shaped olive landscapes.

Population genetic structure and dispersal patterns of a cooperative breeding bird in variable environmental conditions

Understanding the effects of environmental conditions in cooperatively breeding species helps reveal the nature of evolutionary forces leading to this type of social system. In particular, environmental variability may affect demographic processes such as mortality and dispersal which can ultimately define the fine-scale genetic structure of cooperatively breeding populations, including direct and indirect fitness opportunities for individuals. We investigated the population genetic structure and dispersal patterns of obligately cooperative white-winged choughs, Corcorax melanorhamphos , exploring within-group relatedness and genetic differentiation among groups sampled over several years of above average rainfall. We compared our results with data from a previous study in the surrounding area, conducted during a drought period. White-winged chough groups showed similar significant genetic differentiation among groups during both drought and nondrought periods. However, we found female-biased dispersal during abundant rainfall years, which contrasts with the previous study conducted during a drought. We also examined differences in genetic structure in the present study, between groups breeding in suburbs versus native woodlands, finding higher within-group relatedness in woodland birds. Dispersal was female biased in both suburban and woodland habitat but subadult females in suburban habitat were more likely to disperse than adult females. We suggest that higher mortality in chough populations (both during a drought and in suburban habitats) led to more breeding opportunities, resulting in higher dispersal, and reflecting lower group stability. Our study suggests ecological conditions are important drivers of social structure in a cooperatively breeding bird, which are likely to be impacted by environmental change, including climate and urbanization. • Chough groups show significant genetic variation in drought and nondrought years. • In nondrought years, in both suburbs and woodland, dispersal is female biased. • Among suburban females, subadults are more likely to disperse than adults. • In drought years dispersal is not sex biased.

Seasonal Distribution of Halyomorpha halys (Hemiptera: Pentatomidae) Captures in Woods-to-Orchard Pheromone Trap Transects in Virginia.

The invasive brown marmorated stink bug, Halyomorpha halys (Stål), is a pest of numerous economically important crops in the USA. In the Mid-Atlantic region, it is a significant, direct pest in tree fruit orchards, many of which are bordered by woodlots containing a variety of its deciduous tree and shrub hosts. During the growing season, H. halys moves from woodland habitats into crops, but seasonal changes in its relative abundance between these adjacent habitats have not been examined. Using linear transects of six pheromone-baited pyramid traps that extended from 100 m into the interior of woodlots to 100 m into the interior of adjacent commercial apple orchards in Virginia, spatiotemporal changes in H. halys captures were measured during three growing seasons. Captures of H. halys adults and nymphs were recorded weekly from May through October, and annual data were separated into early, mid, and late-season captures. Only adults were captured during the early season, and there was no indication of a spatial trend in captures across traps in the transects among years. Beginning in mid-season and becoming increasingly apparent by late season, captures of H. halys adults and nymphs tended to become most frequent in traps at the woods and orchard edges and at 50 m into the orchard interior. These findings conform with and expand upon previous research documenting an edge effect for H. halys relative abundance and can inform and support the optimization of perimeter-based management strategies for H. halys in Mid-Atlantic apple orchards.