The impacts of beavers Castor spp. on biodiversity and the ecological basis for their reintroduction to Scotland,UK

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Habitat variation and population regulation in Sparrowhawks

In a study area in south Scotland, Sparrowhawks did not occupy the available nesting places at random, but more often used those places where breeding success was highest (here called high-grade places). Most birds stayed on particular nesting places for only one year, but others stayed up to 8 years. Some birds moved from low- to high-grade places as they aged. Continued occupancy of certain places was thus produced by many different individuals occupying such places in rapid succession, but most staying for only one breeding season.
On the most used (high-grade) nesting places pairs produced more than enough young per breeding attempt to offset the average annual mortality, but on the less used (low-grade) places they produced too few. Low-grade nesting places therefore acted as a sink, whose occupancy could be maintained only by continual immigration. Over the study area as a whole, the population was in balance, with reproduction matching mortality.
Habitat changed over periods of 15–30 years, as woodland matured. Nesting places in young woods, with small densely-growing trees, showed the highest occupancy and nest success. Both aspects of performance declined as the woodland aged, and trees became larger and more widely spaced. Long-term stability in nest numbers and success in the study area as a whole was associated with a system of rotational forest management, which ensured a continuing availability of young woods.
It is proposed that spatial variation in habitat quality is involved in the regulation of breeding numbers. Removal experiments confirmed the presence of non-breeders, which could attempt to breed when high-grade nesting habitat was made available to them, but otherwise remained as non-breeders despite the presence of vacant low-grade habitat. This situation, involving an interaction between habitat quality and bird quality, probably occurs in some other raptors too.     

The relationships between Ixodes ricinus and small mammal species at the woodland–pasture interface

Ixodes ricinus, as vector, and small mammals, as reservoirs, are implicated in pathogen transmission between wild fauna, domestic animals and humans at the woodland–pasture interface. The ecological relationship between ticks and small mammals was monitored in 2005 on four bocage (enclosed pastureland) sites in central France, where questing ticks were collected by dragging and small mammals were trapped. Questing I. ricinus tick and small mammal locations in the environment were assessed through correspondence analysis. I. ricinus larval burden on small mammals was modeled using a negative binomial law. The correspondence analyses underlined three landscape features: grassland, hedgerow, and woodland. Seven small mammal species were trapped, while questing ticks were all I. ricinus, with the highest abundance in woodland and the lowest in pasture. The small mammals were overall more abundant in hedgerow, less present in woodland and sparse in grassland. They carried mainly I. ricinus, and secondarily I. acuminatus and I. trianguliceps. The most likely profile for a tick-infested small mammal corresponded to a male wood mouse (Apodemus sylvaticus) in woodland or hedgerow during a dry day. A. sylvaticus, which was the only species captured in grassland, but was also present in hedgerow and woodland, may be a primary means of transfer of I. ricinus larvae from woodland to pasture.     

Impact of deer in lowland Britain on agriculture, forestry and conservation habitats

Probably in response to recent changes in habitat structure, populations of a number of species of deer are increasing both in numbers and in geographical distribution in lowland Britain. In the wake of this expansion there is increasing awareness and concern over damage to agriculture/horticulture and forestry, as well as damage to sensitive vegetation in conservation areas. Despite a perception that damage levels are rising, data that actually quantify the scale of impact by deer on lowland agriculture and forestry interests or conservation habitats are scarce. This review attempts to draw together such objective data as are available to assess more formally the actual impact of deer damage in these different contexts and the economic significance of damage caused. The review concludes with a brief consideration of implications for management. The majority of agricultural damage reported in England and Wales was due to Fallow, Red and Roe Deer; Muntjac were only implicated in a little horticultural damage where they are numerous. Most reports were of damage to pasture or cereals, with oilseed rape, nursery and orchard crops also frequently damaged. Because of fundamental differences in ecology and distribution, different species of deer were implicated in different types of damage, depending on feeding habit and distribution in relation to geographical patterns of crop-type. In a woodland context, Fallow, Red and Roe Deer were implicated in the majority of reported damage in lowland UK, which is most frequent in the north of England and lowest in Wales. Despite the apparent severity of damage caused to agriculture or forestry, the actual economic significance of such damage would appear in many cases to be negligible or small. Field crops frequently recover completely from such damage, and although woodland crops may be checked and quality of the timber may be reduced as a consequence of earlier browsing damage, losses may be far less than they first appear. This whole question of the true economic cost of deer damage needs further research. Deer damage to conservation habitats in England and Wales appears largely restricted to woodland; impact on heathlands, grasslands and wetlands is generally welcomed as helping to arrest invasion of scrub. Within woodlands, while concern is expressed in a small number of cases over losses of sensitive ground flora or suppression of natural regeneration, the major problem is in damage to coppice regrowth on sites where coppice management has been recently reintroduced.     

What future for British red squirrels?

The geographic range of red squirrels contracted sharply in Britain during the 1940s arid 1950s, as increasingly large areas were colonized by the congeneric North American grey squirrel. Red squirrels remain common only on offshore islands, and in the large conifer forests of northern England and Scotland. The initial replacement of red squirrels was in arras dominated by oak woodland, probably because acorn crops are exploited less efficiently by red squirrels than by grey squirrels. Dirt studies have shown that acorns are digested less efficiently by the red squirrel, which occurs in conifers through most of its Eurasian range, than by the introduced grey squirrel, which is primarily a native of deciduous woodland. The red squirrel will probably be replaced in deciduous and mixed woodland throughout mainland Britain, and may eventually persist only in large areas of conifers which arc far from oak trees. The conservation of red squirrels on islands is therefore particularly important for their survival, perhaps making it worthwhile to create new island populations where they do not at present exist.     

Flight patterns of butterfly species in woodlands

Summary The flight patterns of twenty species of butterflies present in two coniferous woods and one coppiced wood in eastern England were recorded from April to September 1979. The most mobile species were those characteristic of disturbed habitats, with spatially segregated larval and adult habitats, and those butterflies with early successional larval host plants. The least mobile species were those of permanent habitats and those with ubiquitous larval host plants. Flights of poorly vagile species, but not vagile species, were restricted in both coniferous and coppiced woodland, but were shorter in the latter due to the presence of vegetational barriers to flight. Vagile species remained in coppiced areas longer than in areas of coniferous woodland, flights being influenced by the location of larval and adult food resources.     

The abundance of various polymorphic microsatellite motifs differs between plants and vertebrates.

The abundance of different simple sequence motifs in plants was accessed through data base searches of DNA sequences and quantitative hybridization with synthetic dinucleotide repeats. Database searches indicated that microsatellites are five times less abundant in the genomes of plants than in mammals. The most common plant repeat motif was AA/TT followed by AT/TA and CT/GA. This group comprised about 75% of all microsatellites with a length of more than 6 repeats. The GT/CA motif being the most abundant dinucleotide repeat in mammals was found to be considerably less frequent in plants. To address the question if plant simple repeat sequences are variable as in mammals, (GT)n and (CT)n microsatellites were isolated from B.napus. Five loci were investigated by PCR-analysis and amplified products were obtained for all microsatellites from B. oleracea, B.napus and B.rapa DNA, but only for one primer pair from B.nigra. Polymorphism was detected for all microsatellites.     

内蒙古达赉湖自然保护区狼食性的季节性变化

2004年7月到2005年6月在达赉湖自然保护区收集狼(Canis lupus)的粪便,采用粪便分析法研究食性的季节性变化。由于野生有蹄类动物严重匮乏,家畜已成为该地区狼的主要食物:草青期的频率为74.7%,相对生物量达到94.4%;草枯期的频率为67.6%,相对生物量达到91.8%。该地区的家畜主要有绵羊、山羊、牛和马,狼食性的季节性变化主要与家畜的放牧方式有关。兔类和小型啮齿类动物是狼次要选择的食物。该地区鸟类资源丰富,是狼较稳定的食物(草青期6.2%,草枯期7.8%)。为降低该地区狼对家畜的捕食,建议管理部门合理控制狼的数量,引入牧羊犬及加强对牛、马的管理。     

Seasonal population changes of myxomycetes and associated organisms in four woodland soils

Abstract The number of myxomycete plasmodium-forming units (PFUs) and associated microorganisms in soils from four woodland sites in the West of England were estimated at approximately monthly intervals over the course of a year, and other characteristics of the soils were determined. The numbers of PFUs were low except in an unusual high-phosphate woodland soil. This soil contained the fewest dictyostelid slime moulds. Conversely, the woodland soil with most dictyostelids contained the fewest PFUs. Naked soil amoebae were the most abundant phagotrophs. Myxomycetes were a comparatively small component of the phagotrophic community of the three typical woodland soils. Changes in the populations of naked amoebae, ciliates, myxomycetes and dictyostelids were sometimes synchronized with changes in the bacterial populations, which showed 9–35-fold seasonal variations in abundance at the four sites.     

Breeding success of Spotted Flycatchers Muscicapa striata in southern England – is woodland a good habitat for this species?

The UK population of the Spotted Flycatcher Muscicapa striata has declined markedly in the last 30 years but there have been few recent studies of the species. This study examined the relationship between nest success and the predominant habitat type around Spotted Flycatcher nests in two contrasting areas of England. A breeding population in eastern England, a region where numbers of Spotted Flycatchers are known to have decreased dramatically in recent decades, was compared with another in southwest England, where numbers have remained stable or even increased. Whilst there was no difference in breeding success between the two study areas, there were significant differences between habitats, with garden nests more successful than those in farmland or woodland, at both egg and chick stages. Estimates of productivity per nesting attempt were also lower in farmland and woodland, with nests in gardens fledging twice as many chicks as those in either woodland or farmland. The proximate cause of lower success in farmland and woodland was higher nest predation rates during both egg and chick stages. In terms of nesting success, farmland and woodland appear to be similar in quality for this species, but both appear to be suboptimal habitats when compared with gardens, providing evidence of a problem on the breeding grounds for this species, in at least these two habitats.     

The distribution of pathotypes of the cereal cyst-eelworm Heterodera avenae in England and Wales

Two pathotypes of the cereal cyst-eelworm (Heterodera avenae), occurred commonly in England and Wales and a third pathotype was apparently present in low numbers in a few areas. Pathotype 1, which can breed on most cultivars of wheat, barley and oats, but not on Drost barley nor barley cultivars containing the gene for resistance from barley No. 191, was most common in the south west of England. Pathotype 2, which can breed on most cereals, including Drost barley but not No. 191, was common throughout England and Wales and mixtures of these pathotypes occurred in many places. Pathotype 3, which can breed on barley No. 191 and probably on Drost and most cultivars of cereals, was rare and was found only in low numbers together with either or both Pathotypes 1 and 2. In the initial tests it was present or suspected in only nine fields (6%), but when these soils were retested in more detail the following year, Pathotype 3 was confirmed at only one site.     

The phenology of Syrphidae (Diptera): are they Batesian mimics of Hymenoptera?

The phenology of aculeate Hymenoptera and of syrphids which are believed to mimic them has been investigated at three semi-natural ancient woodland sites in north-west England. It is concluded that the abundance and phenology of most of the hoverflies is consistent with their being Batesian mimics of particular species of bee or wasp. The main exceptions are Eristalis spp., Helophilus spp., Syrphus spp. and Episyrphus balteatus which are often much more abundant than their supposed models. These four taxa may still benefit from mimicry, but further research is needed to confirm this. With the possible exceptions of Eristalis pertinax and E. tenax , there is no strong evidence from north-west England in support of Waldbauer's hypothesis that mimics are rare when fledgling birds are abundant but may be commoner in autumn and spring. The data also indicate that mimics which closely resemble their models (specific mimics) are usually rarer than their models, whereas mimics with a less precise resemblance (non-specific mimics) are often commoner than models.     

Variations in Black Grouse Tetrao tetrix winter survival in a year with prolonged snow cover

Capsule Low Black Grouse survival rate in northern England during a severe winter with prolonged snow was attributed to limited availability and proximity of woodland.

Aims To compare the impact of the severe winter weather on Black Grouse in an open treeless landscape in northern England with more wooded landscapes in Scotland.

Methods We assessed the impact of severe winter conditions in relation to previous milder winters at a sample of leks counted annually in northern England and the Scottish Highlands between 2001 and 2012. In addition, following the severe winter in 2009/10 Black Grouse were surveyed at all leks in 2010 where they were surveyed the previous year. We assessed woodland habitat extent within 1 km of leks and related this to indices of Black Grouse over-winter survival.

Results Black Grouse in northern England were severely affected by the severe winter of 2009/10, declining by 38% in comparison to a 23% increase in the Scottish Highlands. Leks in northern England were at higher altitudes and had less tree cover than those in Scotland.

Conclusion The lack of woodland cover around leks in northern England implies that availability of above snow forage, shelter and cover from predators was too low for Black Grouse to survive during prolonged deep snow. Measures are required to provide emergency food sources in periods of prolonged snow, such as the provision of supplementary food at leks, the cultivation of seed-rich arable crops, and the establishment of pockets of woodland.     

The diet of the feral cat (<Emphasis Type="Italic">Felis catus</Emphasis>) in north-eastern Australia

The domestic cat Felis catus has become a feral predator and conservation threat in many regions of the world. In the northern tropical savannas of Australia, there is limited data on feral cat diet, and there is evidence that some mammal populations in this region are starting to show signs of significant population decline. A total of 169 cat stomach samples were collected from north-eastern Australia from 1996 to 1998. Samples were collected from grassland and woodland habitats in winter and summer periods. A total of 106 unique prey types (grouped into 59 categories), representing 974 items, were recorded from all samples of which 8% were invertebrates, 9% amphibians, 41% reptiles, 20% birds, and 22% mammals. Relative significance of prey items was examined by calculating the Index of Relative Importance. Chi-square comparisons of frequency differences among habitat, season, and sex of cat were also undertaken. The most important prey items were grasshoppers (Orthoptera), centipedes (Chiloptera), dunnarts (Sminthopsis spp.), planigales (Planigale spp.), rabbits, quails (Turnix spp., Coturnix sp.), and geckos (Oedura spp., Gehyra spp.). Amphibians and invertebrates were more frequent in summer (wet season) samples, and mammals were more frequent in winter. Similarly, there were more amphibians in woodland samples and more invertebrates in grasslands. There was high dietary overlap and little difference in the diet of male versus female cats. Increasing cat predation in northern Australia may significantly affect the conservation of key groups already under decline (e.g., mammals) and careful innovative solutions to stem cat predation are needed.     

Biological invasions provide a framework for reintroductions: selecting areas in England for pine marten releases

We suggest that reintroductions, like biological invasions, have two phases: establishment when a new population becomes self-sustaining, and spread when a population increases its distribution. Stochastic effects on mortality and sex ratios are most likely to determine whether a population becomes established, while factors influencing birth rates will probably most influence spread. Using this establishment-spread structure, we evaluate the autecological suitability of regions in England for pine marten Martes martes reintroductions. Risks of mortality from predator control, traffic accidents and predation by foxes were used to evaluate suitability for establishment. Mortality risk was higher in all potential release regions in England (selected as having 25% or more woodland cover) than in regions of current pine marten distribution in Scotland; risk of predation was higher in the latter. Indices of prey abundance were used to evaluate suitability for populations to spread. Prey indices in potential release regions were generally higher than in regions of current distribution. A relation between prey, woodland cover, and known pine marten densities suggested that potential release regions are capable of supporting relatively high densities of pine martens, though these might be reduced by higher mortality. We concluded that all potential release regions are suitable for pine marten populations to spread. However, reintroductions should first be to regions with lower risk of mortality, in case higher levels of the latter prevent establishment. The suitability of relict regions of distribution in northern England was low until post-war afforestation, suggesting that habitat suitability constrained recovery of relict populations. These regions remain less suitable for reintroductions.     

埃塞俄比亚Alatish国家公园大型哺乳动物多样性、分布及其与栖息地的联系

于2004年8月-2005年3月间研究了Alatish国家公园在雨季和旱季期间大型哺乳动物的多样性和分布.基于地形图、卫片和预调查结果,在4种生境类型中识别出37个100 km2或者更小的斑块.在4个植被类型中随机选择了11个斑块,沿随机选择的样线进行了调查,样线10 km 长,0.2 km宽,覆盖了该区域面积的20%.使用Shannon-Wiener多样性指数、DISTANCE 5.0 软件以及 Simpson相似性指数分析了大型哺乳动物的多样性以及分布的相似性.记录了20种体型较大的哺乳动物;河边林地在雨季和旱季都有最高的多样性,林地的多样性最低;旱季中4种类型的栖息地具有相似的分布型;由于栖息地退化不能确定物种的分布格局.联合距离取样分析揭示出,旱季和雨季大型哺乳动物的密度较低,分别为4.067只/km2和6.263只/km2.所观察的哺乳动物可分为草食动物(15%)、游牧动物(30%)、杂食动物(25%)与食肉动物(30%).     

Wolf (Canis lupus) feeding habits during the first eight years of its occurrence in Germany

Due to the fact that the feeding habits of large carnivores are the main contentious point when they start resettling regions they were absent from for several decades, the diet composition of the wolves in Germany was analysed from the beginning of this process. Wolves in Germany primarily feed on wild ungulates, which make up more than 96% of their diet. The dominating prey species is the roe deer (55.3%), followed by red deer (20.8%) and wild boar (17.7%). The second important food category are the leporids (2.9% of Biomass), whereas livestock makes up only 0.6% of all biomass consumed. Wolves clearly prefer hunting on juvenile to adult red deer; roe deer are not selected after their age. We found seasonal differences in the diet composition with a higher amount of wild boar in spring and winter, when a high amount of juveniles and weakened animals, respectively, are available. In the first years of the study the percentage of red deer was much higher, and the percentage of roe deer therefore was lower than the following years. The amount of wild boar in the wolf diet fluctuated most in the first three years. Diet composition remained constant during the last five years. Wolves needed less than two generations for adapting to the new conditions in the cultivated landscape of eastern Germany.     

The effect of woodland soil translocation on carbon and nitrogen mineralisation processes

Two investigations into the translocation of temperate deciduous woodland soil were carried out in Kent, S. E. England, to study the effects on C and N mineralisation. In the field experiment, two translocation methods were compared: (i) placement, moving soil as an intact surface profile and (ii) loose-tipping in which the surface profile was mixed. These were implemented in winter both in situ (under the woodland canopy) and ex situ (soil moved to a receptor site outside woodland). In a second experiment, intact soil cores from the woodland site were subjected to different levels of disturbance in a polythene tunnel environment. Measurements of soil CO₂ evolution and N mineralisation in both experiments showed a clear seasonal pattern, strongly influenced by temperature. Over a 7-month period, cumulative net N mineralisation in the field was greater in the woodland controls and placement treatments than loose-tipping treatments. Soil CO₂ emissions were also greater in woodland control plots in the winter compared with ex situ treatments. Similarly, in the polythene tunnel environment, CO₂ emissions were highest in the undisturbed soil cores, while N mineralisation varied with soil depth but, across the whole profile, was also greater in the controls. We conclude that the mixing of organic rich topsoil with mineral subsoil in clayey soil may have protected the organic residues on the clay-silt surfaces, resulting in overall lower mineralisation rates in the disturbed soil. These results indicate that N mineralisation does not necessarily increase when soil translocation operations are carried out on clayey soils in winter. Placement methods appeared the most likely to conserve soil mineralisation processes close to those in undisturbed woodland soil, but depend greatly on the success of maintaining the soil profile intact. It appears that, on clayey soils, the development of vegetation at the receptor site is more likely to be determined by alterations in the light, soil temperature and moisture regime that will occur in open conditions after woodland translocation than from increased soil N supply.     

The influence of weather on habitat use by small mammals

Summer habitat use by three species of forest small mammals was determined using tracking stations Nocturnal weather influenced habitat selection by deer mice and woodland jumping mice but not by red-backed voles Deer mice used all habitats equally on clear nights but were most active in mixed forest on cloudy, rainless nights and most active in a coniferous habitat on rainy nights Jumping mice were most active in mixed forest on clear and rainy nights but shifted to coniferous forest on cloudy dry nights Red-backed voles were most active in the coniferous habitat regardless of weather Microhabitat references within habitats reflected the same preferences as habitat selection Microhabitat selection by jumping mice also changes with weather The mechanism most likely responsible for the observed habitat selection changes is changing insect abundance associated with cloud cover and rainfall