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1.
Capsule: Sky Lark plots and additional tramlines increase Sky Lark Alauda arvensis territory densities in winter crops.

Aims: To analyse the effects on Sky Lark territory density of Sky Lark plots and additional tramlines in winter cereals and oilseed rape.

Methods: We mapped Sky Lark territories on fields with Sky Lark plots or additional tramlines as well as on adjacent control sites, from 2010 to 2013 in Saxony, Germany, where agricultural land use is intensive, dominated by winter-sown crops and takes place in large fields.

Results: In test sites with Sky Lark plots, 5.6 and 3.1 territories per 10?ha were found in the early (April/May) and late periods (June/July) respectively, compared to 3.3 and 1.4 territories per 10?ha in control sites. Sky Lark territory densities in fields with additional tramlines were 1.6 times higher in the early period (4.2 versus 2.6 territories per 10?ha) and 2.2 times higher in the late period (3.6 versus 1.6 territories per 10?ha).

Conclusion: Sky Lark plots and additional tramlines improve large fields for the Sky Lark and have the potential to increase the Sky Lark population.  相似文献   

2.
Capsule: Seed abundance but also seed depletion during winter modifies habitat use and aggregation behaviour of Eurasian Sky Lark Alauda arvensis and Meadow Pipit Anthus pratensis.

Aims: To investigate the effect of seed abundance on the density of two passerine birds, the Eurasian Sky Larks and the Meadow Pipit, at an agricultural landscape scale during winter.

Methods: Bird counts as well as seed density measurements were carried out in winter to quantify the aggregative response of farmland birds to seed abundance from November to March.

Results: Seed resources varied by a factor of ten between crop types, but declined so sharply over the winter that seed abundance was low and similar among crop types by late winter. Sky Larks selected for higher seed density plots, but only at the end of winter when the resources were the lowest. Conversely, Meadow Pipits did not show any aggregative response to seed abundance.

Conclusion: These results show that an uptake of seed-rich habitats in agricultural landscape would be very beneficial for wintering granivorous birds, by fulfilling the late winter ‘hungry gap’. The inclusion of seed mixtures in habitats that attract high densities of birds and retain seeds until late winter is of primary interest.  相似文献   


3.
Capsule: The Dupont’s Lark Chersophilus duponti in Iberia has relatively high breeding success in both core and fragmented habitats, so population declines are more likely to be the result of low juvenile or adult survival.

Aims: To measure important aspects of the reproductive biology of one of the most endangered and least known larks: the Dupont’s Lark C. duponti.

Methods: We monitored 36 nests in 2 Spanish shrub-steppes, one holding one of the largest European populations (250 pairs) and one composed by fragmented habitat patches holding a smaller population (50 pairs).

Results: The breeding season went from late-March to early July. Overall mean (±sd) clutch size was 3.47?±?0.56, and the number of fledglings per successful nest was 3.0?±?1.15. Mean nestling period was short (8.2 days). Nests showed similar daily survival rate during the incubation period (0.9750?±?0.0110) as during the nestling period (0.9545?±?0.0168), with a mean breeding success of 50%. Predation was the main cause of complete nest failure (83.3% of failed nests in both localities).

Conclusion: Breeding parameters did show no significant variation between populations. Breeding success in both sites was generally higher than recorded in previous studies of this and most other lark species, which suggests that breeding success does not compromise long-term viability of these populations. The decline of the studied populations should be explained by other causes, such as a general decrease in habitat quality, habitat loss or habitat fragmentation.  相似文献   

4.
Capsule The conservation of Red-backed Shrikes on farmland habitats depends on extensive farming conditions.

Aims To evaluate breeding density and habitat preferences of the declining Red-backed Shrike and relate its occurrence to an environmental gradient ranging from land abandonment to intensive farming.

Methods The study was carried out in the Apennines (northern Italy), at nine 21-ha study plots. We identified factors affecting breeding density and habitat preferences at two spatial scales (landscape and territory) and analysed the variation in territory density according to the relative farming intensity in a low-intensity agricultural landscape.

Results The presence of shrubs and cultivated/grazed land positively influenced the number of Red-backed Shrike territories per plot, while the species' settlement within plots was related to higher values of shrub cover and the presence of hedges. Shrike occurrence was associated with land-use categories intermediate between land abandonment and intensive agriculture.

Conclusions This study provides a first detailed assessment of Red-backed Shrike habitat requirements in southern Europe. Favoured habitats were pasture/cultivation mosaics flanked by or interspersed with shrubs/hedges (15–20% of the surface of the 1-ha medium-sized territory). Thus, the conservation of Red-backed Shrikes in low-intensity southern European farmland appears to reflect a trade-off between agricultural intensification and long-term land abandonment.  相似文献   

5.
6.
Background: Increased soil phosphorus (P) caused by agricultural intensification has been associated with decreased plant species richness (SR) in central Europe. How plant communities and soil P gradients are related in unimproved open habitats remains unclear.

Aims: The aim of this article was to characterise the relationship between soil chemical parameters and plant species composition and richness in unimproved open habitats.

Methods: The influence of soil chemical parameters (pH, P, K, Mg) on species composition was assessed, using data from 40 heathland and 54 grassland plots, by non-metric multidimensional scaling and permutational multivariate analysis of variance. The relationship between soil chemical parameters and SR was tested by linear mixed effects models.

Results: A direct relationship between heathland community composition and pH was observed, explaining 10% of variation in species composition, while P, Mg and pH together explained 17% of variation in grassland composition. In heathlands, SR increased with increasing pH, whereas in grasslands, SR decreased with increasing soil P.

Conclusions: Soil chemical parameters were substantially related to plant community composition and richness. In an area spared from a century of agricultural intensification, reduced pH appeared to constrain SR in heathlands, while even slight P increases (<10 mg kg?1) depressed plant SR in semi-natural grasslands.  相似文献   

7.
Capsule Structural heterogeneity was the most important factor influencing the distribution of Barred Warbler Sylvia nisoria, Common Whitethroat S. communis and Lesser Whitethroat S. curruca in linear habitats in farmland of Western Poland.

Aims To investigate the occurrence of three species of Sylvia warblers in relation to the spatial structure of linear habitats in the agricultural landscape of Western Poland where, in contrast to Western Europe, field boundaries are not managed in terms of their size or spatial structure.

Methods In 2008, the distribution of breeding territories of Sylvia warblers in linear habitats was estimated in farmland of Western Poland. Redundancy detrended analysis was used to assess the relationship between bird abundance and seven linear habitat variables in ninety-four 150?m sections.

Results Sylvia warblers differed in habitat requirements, however heterogeneity affected their distribution to the greatest extent. In addition, Barred Warbler preferred high shrub volume and wider sections, whereas Common Whitethroat was attracted by brambles and nettles and Lesser Whitethroat favoured shrubs. All species avoided a high proportion of low vegetation.

Conclusion Structural heterogeneity resulted in highly preferred linear habitats for Sylvia warblers. Thus, maintaining or increasing structural heterogeneity of linear habitats may be a very effective tool for the conservation of farmland bird populations.  相似文献   

8.
M. J. Goodacre 《Bird Study》2013,60(2):111-113
Capsule Large‐scale intensification of agricultural management during the past 50 years has resulted in a reduction of invertebrate abundance and higher and denser ground vegetation. Food availability for insectivorous birds foraging on the ground has been negatively affected, but the interactions between birds and their food availability are complex and often species‐specific. Populations of Wrynecks Jynx torquilla are declining all over Europe, possibly because of reduced accessibility to their main prey, ground‐dwelling ants, due to higher and denser ground vegetation. However, it is not clear which ground vegetation structures are tolerated by foraging Wrynecks and which habitats are preferred.

Aims To identify the optimal ground vegetation structure and the main habitat types in which Wrynecks search for food.

Method We radiotracked seven Wrynecks in high‐intensity farmland in Switzerland to study foraging habitat use during the reproduction season. Several habitat variables were mapped at each foraging location and compared with locations selected randomly within individual home ranges.

Results Wrynecks preferentially foraged at places with ≥50% bare ground. Vegetation height was not important. Older fruit tree plantations and fallow land were the preferred foraging habitats.

Conclusion Conservation measures should concentrate on preserving semi‐open agricultural landscape matrices with loose ground vegetation cover to provide suitable foraging conditions. This can be achieved even in intensively managed farmland as illustrated in this study.  相似文献   

9.
The Karoo Lark Certhilauda albescens complex, endemic to southwest Africa, is characterized by regional phenotypic variation. Recent consensus has been to recognize two species, Dune Lark Certhilauda erythrochlamys and Karoo Lark Certhilauda albescens, but intermediate forms around the mouth of the Orange River have resulted in some authors treating it as a single polytypic species complex. We reexamined the status of taxa in this group by sequencing a segment of the mitochondrial DNA cytochrome b gene. Most samples were from the area around the mouth of the Orange River, where there is considerable local phenotypic variation. Our results indicate that the complex comprises three species, Karoo Lark, Dune Lark and Barlow's Lark Certhilauda barlowi, separated by 1.9-5.5% sequence divergence. There were no sequence differences among described subspecies, but there was limited variation among Dune Lark individuals (sequence divergence values 0.2-0.4%). The Red Lark Certhilauda burra is closely related to the Karoo Lark complex; indeed, it may be that Karoo Lark is the ancestral form. There was morphological (biometrics and plumage) and behavioural (male display song structure) support for the recognition of Barlow's Lark as a separate species. Species ranges within the complex are allopatric or narrowly parapatric, and they occur in different habitats and climatic conditions. Discriminant function analysis correctly identified 99% of skins assigned to taxa based on range, but a few individuals collected in the contact zone between Karoo and Barlow's Larks exhibited intermediate phenotypes, and further investigations are warranted to search for evidence of hybridization. The newly recognized Barlow's Lark has a maximum range of 18,000 km2. It appears to have disappeared from heavily grazed farms around Aus, southern Namibia, and occurs almost exclusively in diamond mining areas, where domestic livestock are excluded. Changes to land use practices which reduce vegetation cover could seriously impact this species.  相似文献   

10.
Background: Although lianas are important in forest ecosystems, information on the environmental factors influencing their diversity, structure and habitat associations is scanty.

Aims: This study had the aim of determining variation in liana diversity, structure and habitat associations across different topographic habitats, and the environmental factors influencing them, in the Penang Hill Forest Reserve, Malaysia.

Methods: Liana diversity, structure and habitat associations were examined in 30 plots, 40 m × 40 m, randomly demarcated within three topographic habitats (flatland, slope and valley). The physico-chemical properties of the soils in the plots were determined and the altitude and slope of the plots recorded.

Results: Liana species richness, diversity and structure varied significantly among the topographic habitats. Liana species richness, diversity and abundance variations were related to soil moisture, phosphorus content, pH and altitude, whereas liana diameter and basal area were associated with soil magnesium and slope. A total of eight species had a positive association with the habitat and a further six showed a negative association. Four species had a positive association with the flatland habitat, but only three and two species, respectively, with slope and valley habitats. The slope habitat gave the highest number of species that showed a negative association.

Conclusions: Liana diversity and structure varied between habitats. Some liana species showed different associations with specific habitats. Environmental variables were identified that influence liana diversity, structure and habitat associations. The study provides important information about the factors influencing liana success, and these will be of value in liana conservation and management in tropical forests.  相似文献   


11.
Capsule: The 2007 national survey of the UK breeding population of Little Ringed Plovers shows a further spread into Scotland and Wales since the previous survey in 1984. In contrast, there has been a significant decrease in the Ringed Plover breeding population.

Aims: To provide new breeding population estimates in the UK and Great Britain for Little Ringed Plover Charadrius dubius and Ringed Plover Charadrius hiaticula in 2007 and investigate changes in breeding distribution and habitat use since 1984.

Methods: Breeding population estimates were made by combining counts of pairs from ‘key sites’ (2?×?2?km tetrads known to be occupied in/since 1984) and estimates of the numbers of pairs away from these sites based on stratified sampling. Survey periods for Little Ringed Plover: 15 April to 15 July, three visits; Ringed Plover: 15 April to 30 June, two visits.

Results: Population estimates, for 2007, of 1239 (95% confidence intervals: 1175–1311) pairs of Little Ringed Plover and 5291 (5106–5478) pairs of Ringed Plovers were calculated for Great Britain, with 5438 (5257–5622) pairs of Ringed Plover estimated in the UK. Counts of Ringed Plover at inland and coastal sites, covered in both 1984 and 2007, decreased by 83% and 53%, respectively. The Little Ringed Plover population has expanded in range northward and westward since 1984. Main habitats used in 2007 by Little Ringed Plover were inland gravel and sand (25.9%) and river shingle (17.8%); and, for Ringed Plover, coastal shingle and sand (38.5% and 13.7%, respectively) and machair plus associated habitats (23.8%) in the Outer Hebrides.

Conclusions: Between 1984 and 2007, the Little Ringed Plover breeding population in the UK increased considerably, expanding northward and westward, with increased use of river shingle habitats. During the same period Ringed Plover breeding numbers in the UK declined considerably in both coast and inland habitats, likely to be due to human disturbance and habitat change, respectively.  相似文献   

12.
Using data from the National Wolf Census, carried out in Poland in 2000–2001, and GIS techniques we analysed habitat selection by wolvesCanis lupus Linnaeus, 1758 in uplands and mountains of southern Poland. We compared ten habitat variables and two parameters related to wolf abundance in 52 circular plots (154 km2 each) with recorded wolves and 97 randomly selected plots with no signs of wolf presence. Wolf plots were characterized by higher elevation and closer location to the state border than wolf-free plots. Furthermore, wolf plots had higher forest cover, but smaller number of villages and towns and shorter railways and roads than plots without wolves. The best model explaining wolf distribution included forest cover, number of villages, length of roads and railway lines. Compared to northern Poland, the southern part of the country offers worse habitats for wolves due to significantly denser network of settlements and transportation routes.  相似文献   

13.
Capsule Habitats in lowland South Iceland sustain bird populations of international importance, with highest densities in wet habitats.

Aims In areas important for biodiversity there is an urgent need to assess large-scale variation in the biodiversity value of habitats to inform management. We carried out a large-scale survey to assess the conservation value of sub-arctic, Icelandic bird habitats.

Methods Bird counts were carried out on 200 transects in the five most common vegetated habitat types in South Iceland. Based on these counts, breeding bird density and diversity were compared between habitats and total population sizes of common species in these habitats were calculated.

Results Overall, eight species (seven waders and Meadow Pipit) composed over 95% of all birds counted. The combined density of those species exceeded 275 birds/km2 in all habitats. The two wettest habitat types had the highest density of birds.

Conclusion Wet habitats in lowland South Iceland held particularly high densities of breeding birds, notably waders, which constitute populations of international importance. Wet habitat types are generally of higher value for more species, than dryer ones.  相似文献   

14.
Capsule Skylarks breeding in Ireland prefer extensive grassland habitats and almost completely avoid tillage habitats.

Aims To describe the distribution and habitat use of breeding Skylarks in Ireland, particularly in lowland agricultural habitats, and to use this information to inform conservation measures for this species.

Methods Countryside Bird Survey (CBS) and Farmland Bird Project (FBP) data were examined to determine large-scale (national) distribution and habitat selection, in addition to smaller-scale (farm- and field-level) habitat use. The CBS is a national breeding bird monitoring scheme involving 397 1-km squares. The FBP collected detailed bird and habitat data from 122 farms.

Results CBS and FBP data both showed significant regional differences in breeding Skylark densities, with the highest relative abundances in the northwest and west. Dry grassland/grass moor habitats supported the highest densities of breeding Skylarks in the CBS, which were significantly higher than in improved grassland or tillage. At the farm-level, Skylark numbers were positively related to wetland habitats but negatively associated with trees in field boundaries, dense ground vegetation and overall density of farm boundaries. At the field-scale, larger fields and unimproved grasslands were preferred.

Conclusion Agri-environment measures tailored to region-specific requirements and to the relatively local habitat preferences of target species are required if population declines of species of conservation concern, including Skylarks, are to be reversed.  相似文献   

15.
Capsule Peatlands are very important habitats for birds despite low species diversity.

Aims To describe the variation in breeding bird populations that occur on different types of Irish peatlands and their associated habitat characteristics.

Methods Bird abundance and diversity were compared between four peatland habitat types (fens, raised bogs, Atlantic blanket bogs and montane blanket bogs) at 12 study sites using transects. Various measures of habitat quality were also taken at each location.

Results Only 21 species were recorded during the study, with Meadow Pipit Anthus pratensis and Sky Lark Alauda arvensis accounting for over 80% of all birds recorded. Fens had greater bird species diversity and densities than the other three peatland types. Raised bogs, Atlantic blanket bogs and montane blanket bogs were very similar in terms of their avian diversity. Each of the recorded bird species was associated with different aspects of the peatland habitat.

Conclusion This study shows that despite the relatively low avian species diversity of Irish peatlands, they are of enormous conservation value due to the presence of species of high conservation concern such as Willow Ptarmigan (Red Grouse) Lagopus lagopus and Eurasian Curlew Numenius arquata.  相似文献   

16.
Capsule: Trophic status of a deep-water lake was the main driver of changes in breeding population size of Great Crested Grebes Podiceps cristatus while reproductive success was also strongly affected by weather parameters.

Aims: To determine the effects of changes in nutrient status of a formerly highly-eutrophicated deep-water lake and other environmental parameters on a Great Crested Grebe population during a phase of re-oligotrophication.

Methods: Annual surveys were carried out on a natural lake in Switzerland over a period of 25 years to determine breeding population size and reproductive success. The effects of phosphorus content, other limnological parameters and weather variables were analysed with quasi-Poisson models.

Results: The breeding population increased from 80 pairs in 1992 to 417 pairs in 2001, after which numbers showed strong fluctuations. Total phosphorus content in the lake had a strong negative effect on breeding population size. A significant positive correlation was found with the national population index. Reproductive success fluctuated strongly but showed an overall decline. The model indicated positive effects on reproductive success of phosphorus and negative effects of the number of days with strong wind. Rapid water-level increases in early summer and water transparency in June led to higher proportions of late broods.

Conclusion: Phosphorus concentration was identified as the main driver affecting the breeding population of Great Crested Grebes during the phase of recovery of the lake from a highly-eutrophic state. Results indicate that mesotrophic to eutrophic conditions enabled a large population and high breeding success. Reproductive output was further negatively affected by strong wind during a critical breeding phase.  相似文献   

17.
Capsule Golden and White‐tailed Eagles selected different habitats for nesting.

Aim To investigate differences in nesting habitat used by sympatrically breeding eagles in western Scotland, following reintroduction of White‐tailed Eagles from 1975 onwards.

Methods Nest‐site locations from national surveys in 2003–05 were entered into a geographical information system (GIS) in order to measure a set of geographic parameters for each nest site. Binary logistic regression with backwards deletion of non‐significant terms was used to derive minimum adequate models at two spatial scales of the likelihood of an eagle nest belonging to one species or the other. We compared changes in occupancy between 1992 and 2003 of Golden Eagle territories inside and outside a GIS model of potential White‐tailed Eagle habitat and according to proximity to White‐tailed Eagle nests.

Results White‐tailed Eagles nested at lower altitudes than Golden Eagles, in more wooded habitats with more open water close by, tending to nest in trees where these were present. There were 3359 km2 of potential White‐tailed Eagle nesting habitat within 25 km of existing White‐tailed Eagle nests, containing 54 Golden Eagle territory centres, but we found no difference in change of occupancy for Golden Eagle territories close to White‐tailed Eagles compared with those further away.

Conclusion White‐tailed and Golden Eagles appear to partition nesting habitat in the west of Scotland by altitude. This corresponds with behaviour in western Norway and with the situation described in historical accounts of nest‐sites in western Scotland prior to extinction of White‐tailed Eagles. It is also consistent with recent studies showing little overlap in breeding season diet of Golden and White‐tailed Eagles in western Scotland, and likely partitioning of foraging habitat by altitude. We conclude that the likelihood of competitive exclusion is less than previously suggested.  相似文献   

18.
Capsule A long-term decline on this habitat is shown to be associated with the intensification of agricultural management, particularly the occurrence of field drainage.

Aims To assess long-term trends in the number of breeding Lapwing and determine the relationship between these trends and changes in agricultural management on an upland study area.

Methods Breeding Lapwing were counted along two road transects in nine years between 1980 and 2002, and on one extensive plot in 1980, 1990 and 2000. Counts along the road transects were made from a vehicle and the fields used for nesting were recorded. Changes in field management along the transects were monitored annually between 1980 and 1990, and habitat composition assessed in 1980, 1985, 1990 and 2000.

Results During the first 20 years of study the number of breeding Lapwing declined substantially on all three count areas and by 77% overall, with further declines on both transects in 2002. The area of unimproved grassland and arable on these transects also declined substantially due to conversion to improved grass. Fields that comprised either unimproved grassland or arable were most likely to hold nesting Lapwing, while the chance of a field losing its nesting Lapwing was positively associated with the occurrence of drainage. Drainage and conversion to improved grass were closely linked.

Conclusions Agricultural intensification is a probable cause of decline in the number of breeding Lapwing in upland areas. Such declines may have been widespread in upland areas following increased agricultural intensification in recent decades.  相似文献   

19.
Capsule Clutches of hole-nesting passerines suffer less predation if nestboxes are moved by 800–3000 m.

Aims To see if Pine Marten predation upon clutches of insectivorous birds increases with the age of nestboxes and to see if predation is affected by the distance nestboxes are relocated from the plots where predation occurred the previous year.

Methods The study was undertaken in two habitats of central Italy (deciduous and Holm Oak wood). In each habitat, nestboxes were placed and relocated in order to have plots with: new (first year of placement) or old (second year of placement) nestboxes; short (100 m) or long-distance (800–3000 m) relocated nestboxes following previous predation.

Results After controlling for habitat, hole-nester density, competition with snakes and nestbox age, the plots with nestboxes replaced at a short distance from the original location suffered higher predation pressure. Pine Marten predation was higher in plots with older nestboxes. A high predation rate was observed in nestboxes replaced in plots where they had not been present for one year and where they had been heavily preyed on in past years.

Conclusion To reduce the risks of predation by mammals, the relocation of old nestboxes should be carried out at a long distance from plots where predation had previously occurred.  相似文献   

20.
Agricultural habitats are assumed to be biodiversity refuges. However, some studies treat agricultural land management as a cause of the biodiversity decline, to which habitat loss and heterogeneity may contribute. Between the crops, the successional habitats appear – ruderal plant communities and bush areas. Their influence on farmland biodiversity is unknown. This research assessed the impact of spatial relationships between agricultural areas, semi-natural meadows and successional habitats on the bird species richness, Shannon diversity index, and Faith’s phylogenetic diversity index. An additional habitat variable was the presence of weeds, i.e., invasive Caucasian hogweeds Heracleum sp., treated as crops in the past. The birds and habitats research was on 74 sites set in pairs (invaded vs control) in south-eastern Poland. Results showed that birds assembling in agricultural and semi-natural areas were more diverse and contained protected farmland species, while birds appearing in overgrown habitats (i.e., successional and invaded) were clumped with their habitat requirements. In the presence of plant invaders, ruderal habitats negatively affected the bird phylogenetic diversity index. In invaded sites, bush areas had no positive effects on the Shannon diversity index and species richness of birds, in contrast with control sites. The presented research suggests the need to re-evaluate the importance of successional non-crop habitats considered positive in agricultural landscapes if those habitats develop in areas with plant invasion.  相似文献   

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