Field Hedges Research Articles

Linking trends of habitat types and plant species using repeated habitat mapping data

AbstractAimsTrends in the extent of habitat types and species frequencies might not follow a simple pattern. However, data that are able to link those trends are scarce. Here, we use data from a repeated habitat mapping program to test consistency between habitat type and species change.LocationFederal state of Baden‐Württemberg, Germany.MethodsWe derived temporal trends over several decades concerning: (a) the extent of all protected habitat types across the state, (b) plant species across the state, and (c) plant species within habitat types. We tested the consistency between trends in the extent of every protected habitat type with trends of those species that prefer that particular habitat type, as well as with mean trends of all species that occur within that particular habitat type.ResultsWe found that, on average, most protected habitat types decreased in area, with the exception of forests, which showed positive trends. Species analysis showed positive trends for species preferring the habitat types scrubs, copses and field hedges, as well as bog, carr, swamp and alluvial forests. By contrast, negative trends were found for species preferring the habitat types heaths and semi‐natural grasslands, meadows and pastures. While non‐native species increased, species that were considered endangered decreased. A species’ trend across Baden‐Württemberg mostly followed the trend of the species’ preferred habitat type. However, within some habitat types, the mean species’ trend did not follow the trend of those habitat types’ extent. Decreasing species within habitat types were especially those that preferred each particular habitat type.ConclusionsOur results point to an ongoing turnover of floristic composition, and thus to changes in habitat quality within habitat types. This implies that future monitoring programs should track temporal trends of both habitat types and the species occurring in these habitat types as a measure of habitat quality, because they can show diverging trends.

Dead-reckoning elucidates fine-scale habitat use by European badgers Meles meles

BackgroundRecent developments in both hardware and software of animal-borne data loggers now enable large amounts of data to be collected on both animal movement and behaviour. In particular, the combined use of tri-axial accelerometers, tri-axial magnetometers and GPS loggers enables animal tracks to be elucidated using a procedure of ‘dead-reckoning’. Although this approach was first suggested 30 years ago by Wilson et al. (1991), surprisingly few measurements have been made in free-ranging terrestrial animals. The current study examines movements, interactions with habitat features, and home-ranges calculated from just GPS data and also from dead-reckoned data in a model terrestrial mammal, the European badger (Meles meles).MethodsResearch was undertaken in farmland in Northern Ireland. Two badgers (one male, one female) were live-trapped and fitted with a GPS logger, a tri-axial accelerometer, and a tri-axial magnetometer. Thereafter, the badgers’ movement paths over 2 weeks were elucidated using just GPS data and GPS-enabled dead-reckoned data, respectively.ResultsBadgers travelled further using data from dead-reckoned calculations than using the data from only GPS data. Whilst once-hourly GPS data could only be represented by straight-line movements between sequential points, the sub-second resolution dead-reckoned tracks were more tortuous. Although there were no differences in Minimum Convex Polygon determinations between GPS- and dead-reckoned data, Kernel Utilisation Distribution determinations of home-range size were larger using the former method. This was because dead-reckoned data more accurately described the particular parts of landscape constituting most-visited core areas, effectively narrowing the calculation of habitat use. Finally, the dead-reckoned data showed badgers spent more time near to field margins and hedges than simple GPS data would suggest.ConclusionSignificant differences emerge when analyses of habitat use and movements are compared between calculations made using just GPS data or GPS-enabled dead-reckoned data. In particular, use of dead-reckoned data showed that animals moved 2.2 times farther, had better-defined use of the habitat (revealing clear core areas), and made more use of certain habitats (field margins, hedges). Use of dead-reckoning to provide detailed accounts of animal movement and highlight the minutiae of interactions with the environment should be considered an important technique in the ecologist’s toolkit.

Dynamics of Pathogenic Fungi in Field Hedges: Vegetation Cover Is Differentially Impacted by Weather.

Landscape effects might impede or increase spore dispersal and disease risk for crops, as trees and hedges buffer winds and can behave as spore traps, therefore limiting diffusion of fungi, or, on the contrary, behave as disease relay once vegetation is infected and become inoculum sources. In this study, we investigated weekly prevalence of the pathogenic fungus Colletotrichum gloeosporioides on guava tree leaves, differentiating impacts of leaf height on tree, age, and location within leaf. We first estimated differences in prevalence for each covariate, and then related infection rates to weather effects during the year. Our results highlighted a great variance of prevalence among individual trees, and a lower contamination of tree tops, as well as a tendency for greater odds of infection in tips of young leaves compared to older ones. Last, we show evidence that individual tree contaminations are associated with different disease dynamics: early and dispersal-based, late and growth-based, as well as with intermediate dynamic ranges. Pathogen infection dynamics will thus be greatly impacted by cover characteristics at local scale, and tree cover should not be perceived as homogeneously driving disease levels.

Host plants as reservoirs of the main oil-producing cabbage crops pests in the eastern forest-steppe of Ukraine

Considering the geographical position of Ukraine, which is Such biotic factor as the vegetation distribution, which is the forage base for most insects, influences their spreading greatly. This connection is strongly expressed among the harmful herbivorous insects. The presence and distribution of the plants which are cultivated or used by humans and on which the insects are fed is certainly the first and basic condition for the emergence of a zone or a breeding ground of harmfulness. The presence of the most preferred by the insects fodder plants often leads to the formation of a zone or a center of the greatest damage (in the presence of other favorable conditions for the existence and reproduction of the pest). In the course of the researches concerning the identification of the host plants as reservoirs of the main oil producing cabbage crops pests which have been conducted in 2011–2014 in the communities (meadows, roadsides of highways and field perimeters) of the Kharkiv district of the Kharkiv region it has been found out the host plants as reservoirs for the dominant pests of the oil producing cabbage crops were dandelion, caustic buttercup, field mustard, hedge mustard, tansy mustard, yellow rocket and field shepherd’s purse. The largest number of species of the host plants as reservoirs was found on the roadsides of highways and along the field perimeters (6 species) and on the meadows (2 species).The cruciferous fleas, rape blossom beetles and cruciferous bugs visited such crops as field mustard, hedge mustard and yellow rocket most often. Field shepherd’s purse was the least significant among the identified host plants as reservoirs. Only a small amount of the cabbage fleas fed on this crop. This fact can be explained by the small white flowers that do not attract the rape blossom beetles and rose chafers as well as by a ground flat leaf rosette, which is always covered with dust and prevents the fleas and bugs from feeding.

Road verges support pollinators in agricultural landscapes, but are diminished by heavy traffic and summer cutting

Abstract Supporting pollinators in agricultural landscapes is important for reversing their global decline. Road verges and hedges are used by pollinators for feeding and reproduction, but few studies consider entire pollinator communities, and it remains unclear how they are distributed across adjacent verges, hedges and fields, or how they are affected by traffic and verge cutting. We surveyed flowers and pollinators, using transect counts and pan traps, to explore the role of road verges and their associated hedges in supporting pollinators in an agricultural landscape in southwest England, and the impacts of traffic and verge cutting. At 19 sites, we surveyed the road verge (verge edge and verge centre), the verge hedge (both sides), a field hedge and the field interior. Road verges and hedges had a much greater flower abundance, flower species richness and pollinator abundance than field interiors. Verge hedges had far less woody cover than field hedges, but greater flower species richness. There were fewer pollinators along verge edges (next to roads) than along verge centres (2–11 m from roads) and fewer pollinators in road verges next to busier roads. Road verges were generally cut once (in summer), and cuttings were never removed. There were substantially fewer flowers and pollinators in road verges that had been cut, even though surveys often took place many weeks after cutting. Synthesis and applications. Road verges and their associated hedges can provide hotspots of resources for pollinators in agricultural landscapes, but their capacity to do so is reduced by heavy traffic and summer verge cutting. We recommend that beneficial management for pollinators should prioritize wider road verges (at least 2 m wide), roads with less traffic, and areas away from the immediate vicinity of the road. Where possible, verge cutting should not be carried out during peak flowering times.

Variation in Rooting Pattern of Leucaena leucocephala in Relation to Propagation System and Stock Mother Plants

Lateral shoot cuttings are used for multiplication of Leucaena leucocephala clones to control lodging in pulpwood plantations. Variability in rooting pattern was evaluated in lateral cuttings from four types of mother plants (a) sand beds in shade house (SH), (b) sand beds with overhead shade, (c) open sand beds and (d) open field hedges (CMA) in a commercial Leucaena clone. Rooting rate of SH cuttings varied significantly with propagation conditions across two mist chambers (87% in MC 1 versus 68% in MC 2). Rooting pattern also differed with 77% cuttings in MC 1 having long root zone (>2.5 cm length from stem base) compared to only 10% plants in MC 2. Application of rooting hormone (IBA 5000 ppm) increased number of roots by 46% and root zone length by 39% in SH cuttings. Rooting rate did not vary between winter and summer season. Lateral cuttings from open sand bed and CMA had comparatively thicker stem with anatomical configuration of larger pith region, large diameter vessels in low frequency and sclerenchyma bundles, compared to mother plants raised in shade (a and b). Rooting rate was high (83-87%) in covered sand beds (a and b) compared to those (c and d) in open sunlight (43-68%). Majority of cuttings from open sand bed (85%) and CMA (93%) had short root zone (<2.5 cm length) compared to covered sand beds (30%). Clonal propagules with good root system can be produced from Leucaena cuttings when mother plants are maintained in shade and provided suitable propagation conditions.

Expanding networks of field hedges in densely populated landscapes in the Sahel

Changing woody plant density across agricultural landscapes of the Sudano-Sahelian region is a debated issue. This paper reports the results of an investigation on the contribution of field hedges to overall woody plant density. Hedges separating individual cropped parcels were studied within village agropastoral territories in the Dantiandou district in western Niger. In 1992, field hedges were mapped over the study area using aerial photography and in 2016, using high resolution Google Earth imagery. In 1992, field hedge length was equal to 1006 km within 435 km2 of croplands, equivalent to 2.3 km km−2. In 2016, 17.5% of these hedges had disappeared, but 1591 km of new hedges were observed resulting in an increased density of hedges to 5.6 km km−2. In 24 years, hedges had increased at a mean annual rate of 3.7% likely associated with the splitting of crop fields by inheritance.The composition and productivity of hedges were also monitored in 1996, 2010 and 2015. All trees (maximum height ≥ 4 m), shrubs (<4 m) and tussock perennial grasses were recorded within twelve field hedge samples of 200 m each. Field measurements were used to estimate basal area, crown area, foliage mass and wood mass of each woody plant within the sampled hedges. No significant trends were found between 1996 and 2015 in woody plant density, basal area, crown cover, wood and foliage masses across all monitored hedges. However, overall means hide a slight decrease in tree contributions, while shrub contributions first increased and then decreased. They also mask contradictory trends among sites most likely related to different rates of shrub coppicing and tree cutting. The woody species composition of the hedges is poor with an increase of Combretum glutinosum to the detriment of Guiera senegalensis over the study period.Multiplying the hedge sample statistics by the changing lengths of field hedges in the study area provides estimates of the contribution of the hedge woody plants to the woody plant population at a landscape scale. Between 1992 and 2016, field hedges contributed to increases of woody plant density by 3.9%, basal areas by 5.4%, crown cover by 2.7%, leading to 6.1% annual increase in foliage mass and 8.8% increase in wood mass.

Exposure of small mammals, in particular the wood mouse Apodemus sylvaticus, to pesticide seed treatments

Field exposure of small mammals to fungicide-treated wheat seed was investigated over three weeks following drilling on fields near York, United Kingdom. Seed consumption by small mammals trapped on and immediately adjacent to the drilled fields was quantified by measuring the amount of seed in the stomach. In addition, exposure to one seed-treatment, fluquinconazole, was quantified by measuring residues of the fungicide in the stomach, liver, and intestine. The wood mouse, Apodemus sylvaticus, was the dominant species caught on the fields and the only species found to have consumed measurable quantities of seed. Voles, Microtus agrestis and Clethrionomys glareolus, were caught in small numbers, almost exclusively in the field hedge, and showed no evidence of having consumed seed. Stomach-contents analysis revealed that more than 80% of animals trapped in the hedge adjacent to the field had consumed no wheat seed, whereas 98% had consumed less than 10% (by stomach volume). Ninety percent of animals trapped on the field had consumed seed, although 90% of these animals had less than 20% seed in the stomach. Residues of the fungicide in the stomach, intestine, and liver were lower than would be expected for the amount of seed consumed, possibly because of dehusking of the seeds by mice. The relevance of these findings when assessing exposure (and risk) posed by seed treatments to wild mammals is discussed.

Host Plant Preference, Consumption, Growth, Development, and Survival of Tyta luctuosa (Lepidoptera: Noctuidae) on Biotypes of Field Bindweed and Hedge Bindweed

Larval feeding preference, consumption, and development were assessed for the imported noctuid moth Tyta luctuosa (Denis & Schiffermuller) on 4 biotypes of field bindweed, Convolvulus arvensis L., and on hedge bindweed, Calystegia sepium L. No preference, either innate or induced, was observed in 4th and 5th instars for any of the plant types tested. The food source of early instars did not significantly affect later instar development. Food plant type also did not significantly affect maximum larval weight or survival of 1st-5th instars. However, prepupal survival was significantly greater on field bindweed biotype 1. Development from the 4th instar to the prepupa was slower on hedge bindweed than on any of the field bindweed biotypes. Delayed development on hedge bindweed may be related to its higher wet/dry weight ratio. Our findings suggest that T. luctuosa may feed nonselectively on mixed biotypes of bindweed in the field. They also indicate that these biotypes would be generally, but not uniformly, suitable for the development and survival of T. luctuosa .

Performance of field hedge and stoolbed plants of micropropagated dwarfing apple rootstock clones with different degrees of apparent rejuvenation

M. 9 and Ottawa 3 apple rootstocks from micropropagation were evaluated in the field as hedge or stoolbed plants for three or eight years, respectively. The study involved clones of M.9 from in vitro shoot culture lines which had undergone different durations of subculture in an attempt to influence the dgree of subsequent rejuvenation of the micropropagated plants. Subculture of shoots in vitro for up to nine years did not appear to lead to genetic change since the micropropagated plants of both rootstocks were similar to the conventional counterparts with respect to leaf and bark characteristics. Nevertheless, micropropagated hedge plants of both rootstocks had increased production of suckers and in the case of M.9, increased production of burrknots also. Micropropagated hedge plants of both rootstocks also produced summer and winter shoot cuttings with superior rooting performances whilst stoolbeds of micropropagated M.9 gave increased production of shoots and plants compared with their conventionally propagated counterparts. In general, sucker and burr knot production and rooting of cuttings produced from the various micropropagated M.9 stocks increased with increasing durations of subculture of shoots in vitro.

The Woody Species of Hedges with Special Reference to Age in Church Broughton Parish, Derbyshire

SUMMARY (1) A survey of the hedges in one parish in the English Midlands, to examine the relationship between age and number of woody species in 30-yd (27-4-m) samples, is described. Hedges were aged using maps dating back to 1630 A.D. (2) All hedges in the area were basically single-species Crataegus monogyna hedges. They were divisible, on the basis of probable origin and management, into three types, called 'garden', brookside' and 'field hedges'. (3) The woody species in the 'field hedges' could be divided into three groups, based on their ecology, life-form and economic use, called 'commoner shrubs', 'timber trees' and 'rarer shrubs and small trees'. (4) Hedges next to roads had more woody species than those between fields; subsoil was related to number of species, but recent management was not. (5) The number of woody species increased by approximately one a century. This agreed with previous work, but was against a higher 'base number' of 1-87 species. Previous work is discussed, and it is pointed out that less of the variation in number of species is due to age than has been implied. (6) A cessation in increase in number of woody species with age is reported for the first timne. (7) It is concluded that the number of woody species in hedges is of less value in dating than has been assumed, and should only be used for dating groups of hedges when a local relationship has been established empirically between age and number of species.