Microhabitat selection by Eurasian lynx and its implications for species conservation

We studied microhabitat selection of the Eurasian lynxLynx lynx (Linnaeus, 1758) at 116 hunting and 88 resting sites in Białowieża Primeval Forest (Poland) to describe its characteristics and determine the importance of habitat structure for stalking prey and for security during resting. We identified lynx-used sites by radio-tracking 3 male and 3 female lynx. When hunting, the lynx did not select for any type or age class of forest. During both summer and winter, the lynx selected sites characterized by high complexity (number of structures useful for stalking: fallen logs and branches, root plates, patches of dense bushes) and low visibility. In summer, hunting sites were often located in the vicinity of small forest glades that provided good stalking opportunities for lynx and rich foraging resources for roe deer — the main prey of lynx. The habitat at kill sites was more open than at sites where the prey was cached, with higher visibility, lower density of trees and poorer undergrowth. The most important characteristic of resting sites was very low visibility that resulted mainly from using young pine or spruce thickets in the winter and dense undergrowth of oak-lime-hornbeam and ash-alder forests in the summer. The information provided by this study could have direct implications for Eurasian lynx conservation by guiding forest restructuring to better suit the species’ biological requirements.     

Relationship between prey availability and population dynamics of the Eurasian lynx and its diet in northern Belarus

The diet and population dynamics of the Eurasian lynxLynx lynx Linnaeus, 1758 as well as an index of its main prey abundance were studied in transitional mixed forests of northern Belarus in 1985-2004. Monitoring of the lynx population and its main potential prey (the mountain hareLepus timidus, and the roe deerCapreolus capreolus) was done by snow-tracking. Also, abundance of tetraonids (Tetraonidae) was monitored by sight count. Hare numbers were fairly stable during the study period, whereas density of the roe deer population markedly increased, and tetraonids decreased. Composition of the lynx diet was stable seasonally. Lynx fed mostly on hares, roe deer and birds (usually tetraonids) year-round. However, the share of roe deer in lynx diet increased significantly during the period of its higher abundance and the share of tetraonids decreased with their decreasing numbers. There was also a remarkable increase of lynx population, which followed that of the roe deer, despite the pronounced decline of tetraonids. The results of the study emphasised the importance of roe deer as a prey of the Eurasian lynx.     

Winter diets of wolfCanis lupus and lynxLynx lynx in Estonia and Latvia

Winter diets of wolfCanis lupus Linnaeus, 1758 and lynxLynx lynx Linnaeus, 1758 in Latvia and Estonia were investigated in 1997–2000 based on stomach contents of hunted animals and scats. Ungulates appeared to be the staple food for both predators. Lynx diet to a high extent consisted of cervids (Estonia 52% frequency of prey, Latvia 88%), roe deer dominating. Mountain hareLepus timidus made up from 9% (Latvia) to 31% (Estonia) of the lynx diet, and red foxVulpes vulpes 7% in Estonian sample. Wolf diet was more diverse; besides cervids (44% in Latvia, 63% in Estonia) it included wild boar Sus scrofa (32% in Latvia, 17% in Estonia), carrion, small rodents, and other food items. Proportion of empty stomachs was high both in wolves (37%) and lynxes (35%) in Latvia. Range of stomach content weights varied from zero to more than 4 kg in wolves and almost 1.5 kg in lynx. Pianka’s indices of food niche overlapped significantly between species and countries (0.85–0.99).     

Body mass dynamic in Eurasian lynxLynx lynx kittens during lactation

Body mass changes of Eurasian lynxLynx lynx Linnaeus, 1758 kittens during the first four months of their life were studied in 1989–1999 in captivity. Four hundred thirteen records of body mass from 63 lynx kittens were analysed. The body mass of lynx kittens up to four months of age increased as a linear function with age. Daily growth rate (in grams) was minimal when the kittens were switching from milk to solid food at the age 41–60 days and was maximal at the age 61–80 days. Body mass dynamic and daily growth rates of kittens depended on the husbandry conditions of adult animals (or probably on their subspecies) and litter size, but did not depend on the sex of the kittens. Specific spontaneous fights during kittens’ ontogenesis showed the trend to affect kittens’ body mass dynamic and daily growth rate on some stages of kittens’ development.     

Data for estimating eaten prey masses from Eurasian lynx<Emphasis Type="Italic">Lynx Lynx</Emphasis> scats in Central and East Europe

To derive a model which allows estimating eaten prey masses from lynxLynx lynx Linnaeus, 1758 scats, we fed 3 roe deerCapreolus capreolus, 2 wild boarsSus scrofa, 1 fallow deerDama dama, 1 mouflonOvis ammon musimon, 1 European hareLepus europaeus and 1 daily diet of miceMus musculus to two adult lynx. The percentage of prey use decreased with an increase in the offered body mass of the prey individual. Conversion factors from dry matter scat mass to fresh matter mass of eaten prey (y) increased linearly as the eaten mass of the prey individual (x) rose:y = 15.06 + 1.330x,R ² = 0.643,F _1,7 = 12.6,p < 0.01. For estimating eaten prey masses from lynx scats we recommend to use (1) this equation as well as (2) prey type-specific conversion factors and (3) prey type-specific quotients of the eaten prey mass per scat.     

Feeding ecology of the Iberian lynxLynx pardinus in eastern Sierra Morena (Southern Spain)

The feeding ecol ogy of the critically endangered Iberian lynxLynx pardinus Temminck, 1827, was studied in the most important remnant population, located in eastern Sierra Morena (Sierra de Andujar Natural Park, Spain). Three hundred sixty scats were collected from October 2001 through Sep tember 2002. RabbitsOryctolagus cuniculus dominated the lynx diet, as showed by frequency of occurrence (94%) and percent age of volume (91%). Red-legged partridgesAlectoris rufa were the most important secondary prey. No significant seasonal variation was observed regarding the diet preferences of the lynx. No difference was found in lynx diet by comparing two areas with high and low rabbit availability. Juvenile rabbits were positively selected when they were available, during late winter, spring and early summer.     

Distribution and status of lynx in the border region between Czech Republic, Germany and Austria

This paper summarizes available information concerning the presence of the Eurasian lynxLynx lynx Linneaus, 1758 in the Šumava Mountains and adjacent areas along the common border of Czech Republic, Germany and Austria. Our data give an overview of the lynx population occupying the border region between the three countries from 1990 to 1999. We estimated population size using radiotracking data. From 1990 to 1998, population increased from under 20 to nearly 70 resident animals. During this time, reproduction increased as well, with a maximum of 55 kittens observed in the rearing period of 1998 to 1999. Mortality data indicated that illegal hunting was widespread. Our paper discusses possible links with other lynx populations and describes the legal status of lynx in the three different countries. Current management approaches are outlined and steps toward a long-term conservation plan for the population are proposed.     

Spatial interactions between grey wolves and Eurasian lynx in Białowieża Primeval Forest, Poland

Various species of large predators are reported to influence each other through interference or exploitation competition that may affect demography and survival of the subordinate species. We analyzed spatial relationships between grey wolf (Canis lupus) and Eurasian lynx (Lynx lynx) in Białowieża Primeval Forest (BPF, eastern Poland) to determine how they partitioned the space. The wolves (n = 8) and lynx (n = 14) were radio-tracked in 1991–1999. Three wolves and seven lynx were radio-tracked simultaneously in 1994–1996. Territories of wolf packs and home ranges of lynx overlapped considerably (76% of wolf territories and 50% of lynx home ranges, on average). In three cases, their core areas were also overlapping. Wolf-lynx dyads with overlapping home ranges were simultaneously located at distances from 0 to 28 km from each other. We found neither avoidance nor attraction between wolves and lynx occupying the same areas. We concluded that in BPF, the two large predators coexist due to specialization on different preferred prey and heterogeneous habitat.     

Behavioural observations of interactions in a free-ranging lynxLynx lynx family at kills

The behaviour of a free-ranging female lynxLynx lynx Linnaeus, 1758 and her kittens at 12 different kills was studied for 44 hours of observation from September 1996 to March 1997. The development of interactions at kills of a lynx family group showed the following pattern: until the end of September we often observed two lynx, usually both kittens, feed from the kill at the same time. After the age of four months aggression between kittens was observed frequently, with the bigger kitten being dominant. From September the kittens were never again seen feeding together at the kill. However, we never observed fighting, and aggressive behaviour did not increase with the age of the kittens. Whereas until December one of the kittens was always first at the kill, from January onwards it was mostly the adult female who ate first. She introduced her kittens to the home range of a neighbouring female where the family break-up occurred. The kittens were last seen together with their mother on 26 March. Dispersal seemed to be initiated by the female abandoning the kittens.     

Genetic structure of the Eurasian lynx population in north-eastern Poland and the Baltic states

We analyzed the genotypes of Eurasian lynx (Lynx lynx) from three populations in the westernmost part of the species main range. One population was situated at the distribution edge (NE Poland) and the two other (Latvia and Estonia) were located within the main, contiguous range of the species. The aim was to determine if the genetic composition varied among these populations and if there was evidence of isolation among them. Based on microsatellite allele frequencies, we found the allelic richness in Polish lynx to be lower than that in lynx from Latvia and Estonia. We also found significant differentiation among the lynx populations, with the NE Poland population forming a distinct genetic group relative to the two other populations (R _ST = 0.15 and 0.22, P < 0.0001). We suggest that genetic differentiation among lynx populations is the result of habitat insularisation that limits gene flow. This finding emphasizes the necessity to consider the lynx genetic differentiation in conservation planning of this species in Poland.     

Roost tree characteristics determine use by the white‐striped freetail bat (Tadarida australis,Chiroptera: Molossidae) in suburban subtropical Brisbane,Australia

Abstract We examined factors affecting roost tree selection by the white‐striped freetail bat Tadarida australis (Chiroptera: Molossidae), a large insectivorous bat in suburban Brisbane, Australia. We compared biophysical characteristics associated with 34 roost trees and 170 control trees of similar diameter, height and tree senescence characters. Roost trees used by the white‐striped freetail bat had significantly higher numbers of hollows in the trunk and branches (P < 0.003) and were more likely to contain a large trunk cavity with an internal diameter of >30 cm (P < 0.001) than control trees. These trees also accommodated more species of hollow‐using fauna (P = 0.005). When comparing roost trees with control trees of similar diameters and heights, roost trees were on average at a later stage of tree senescence (P < 0.001). None of the roost trees were found in the large forest reserves fringing the Brisbane metropolitan area despite these areas being used for foraging by the white‐striped freetail bat. Although all tree locations in this study were in modified landscapes, roost trees tended to be surrounded by groups of trees and undergrowth. Roost trees provide important habitat requirements for hollow‐using fauna in suburban, rural and forested environments.     

Structure of ant assemblages on street trees in urban Busan,Korea

Street trees planted in urban areas are one of the smallest urban green habitats; however, their role as a valuable refuge for local biota is poorly understood. The aim of this study was to investigate urban street trees as habitat for ants. We found ants on 195 (92%) of 211 street trees studied. Seventeen ant species were collected from five tree species. The two most common ant species were Tetramorium tsushimae (on 112 trees) and Lasius japonicus (on 93 trees). The number of ant species found per tree ranged from 0 to 5, with a mean of 1.55 ± 0.92. The species composition differed significantly among tree species. Nine ant species (Camponotus vitiosus, Lasius alienus, L. japonicus, Nylanderia flavipes, Crematogaster matsumurai, Crematogaster vagula, Monomorium intrudens, T. tsushimae, and Brachyponera chinensis) nested on the trees, mostly in the root zone. Nests were found on 150 trees but were relatively rare on trees with diameter at breast height of less than 40 cm.     

Fungi inhabiting knotwood of Pinus sylvestris infected by Porodaedalea pini

Abundance and diversity of fungi in naturally formed knots of Pinus sylvestris affected by Porodaedalea pini were investigated. Samples were taken from trees that were (i) affected, with internal heartwood decay and no conks, (ii) affected, with internal heartwood decay and conks and (iii) controls. The Illumina sequencing technology was used for amplification of DNA, sequencing and analysis. In total, 566,279 raw sequences were obtained from six samples. Sequences included 74% of culturable and 8.4% of non‐culturable fungi and 17.6% of organisms with no reference sequences in NCBI. Abundance of organisms in knotwood, measured as number of OTUs, ranged from 36,272 (29,506 for fungi) to 178,535 (177,484 for fungi) and differed significantly between two trees in a stand and between stands. The highest and lowest average number of fungal OTUs occurred in infected trees with no conks and in trees with conks, respectively. Number of taxa ranged from 171 to 415 and often differed significantly between two trees in one stand and between stands. Greatest diversity occurred in control trees. The number of fungal taxa shared by two trees in one stand was 67–152 and that shared by two stands was 51–141. The majority of fungi were Ascomycota. Those most common in pines affected by P. pini were Coniochaeta hoffmannii and C. fodinicola (19.65%–59.92%). Infundichalara microchona, Leotiomycetes spp. and Rhinocladiella atrovirens were also present. Another common species, Lecanora conizaeoides, occurred most often in control trees (0.30%–8.82%). Porodaedalea pini was detected only sporadically. Non‐culturable fungi were most frequent in the control trees. The greater average abundance and smaller average diversity of fungi in knots of trees infected by P. pini suggest that the pathogen successfully competes with some fungal species and does not inhibit the growth of survivors. Some fungi detected may contribute to production of natural biocides.     

竞争强度变化对针阔混交林红松和水曲柳径向生长的影响

以3种间伐强度处理下(15%,30%和50%)针阔混交林内优势树种红松(Pinus koraiensis)和水曲柳(Fraxinus mandshurica)为研究对象,基于3次复测数据和树轮宽度数据分析不同间伐强度处理下红松和水曲柳的竞争变化特征,探讨竞争环境变化对保留木径向生长的影响。结果表明,1)红松保留木竞争环境发生变化的单木比例随着间伐强度增加而有所下降,但竞争减弱的保留木所占比例与间伐强度正相关,重度间伐样地内竞争减弱的红松保留木所占比例最大达到63%。不同间伐强度下水曲柳保留木竞争环境发生变化的单木比例一致,竞争减弱的单木比例占50%。2)不同竞争环境的水曲柳保留木径向生长趋势基本一致,而红松保留木径向生长变化趋势有所不同。轻度和重度间伐样地内竞争减弱的红松保留木径向生长在间伐后均呈上升趋势,而中度间伐样地内竞争减弱的红松保留木和各样地竞争不变的红松保留木以及不同竞争强度下水曲柳保留木均在2013年和2014年(间伐后2年内)出现生长抑制,而在2015年(伐后第3年)得到促进。3)随着间伐强度上升,自2015年(伐后第3年)竞争减弱的红松保留木径向生长年增量明显增加,显著...     

Evidence for host plant preference by Iphiseiodes quadripilis (Acari: Phytoseiidae) on Citrus

In this study, we present field and laboratory evidence on the preference of Iphiseiodes quadripilis (Banks) for grapefruit (Citrus paradisi Macfadyen) leaves compared with sweet orange (Citrus sinensis (L.) Osbeck) leaves. This preference was confirmed in four orchards whether leaf samples were taken from either border trees of contiguous grapefruit or sweet orange or interior row trees with both citrus species in adjacent rows. Iphiseiodes quadripilis was most abundant in grapefruit trees in spite of the greater abundance of the Texas citrus mite, Eutetranychus banksi (McGregor) (Acari: Tetranychidae) in sweet orange trees. Similar preference responses were observed in laboratory tests using a Y-tube olfactometer whether I. quadripilis were collected from sweet orange or grapefruit. Iphiseiodes quadripilis collected from grapefruit trees showed significant preference for grapefruit over sweet orange leaves in contact choice tests using an arena of alternating leaf strips (12 mm long × 2 mm wide) of sweet orange and grapefruit. However, I.␣quadripilis collected from sweet orange trees did not show preference for either grapefruit or sweet orange leaves. Based on these results, grapefruit leaves foster some unknown factor or factors that retain I. quadripilis in greater numbers compared with sweet orange leaves.     

Phytoseiid mites (Acari: Phytoseiidae) on apple trees and in surrounding vegetation in southern Finland. Densities and species composition

Leaf samples were collected from sprayed (n=29) and unsprayed (n=19) apple orchards, from the surrounding vegetation (n=58) and from one arboretum (n=12), altogether from 46 plant species (1–5 samples each). The density of phytoseiid mites averaged 1.2 mites/leaf on unsprayed apple trees, but only 0.06 mites/leaf on sprayed trees. The phytoseiid density exceeded 1/leaf onAesculus hippocastani, Aristolochia macrophylla, Corylus avellana, Fragaria vesca, Frxinus excelsior, Juglans cinerea, Pterocarya rhoifolia, Ribes nigrum, Rubus odoratus, Sorbus aucuparia, S. thuringiaca, Tilia×euchlora andUlmus glabra. Other common trees and bushes inhabited by phytoseiids wereCrataegus coccinea (0.2 mites/leaf),Prunus padus (0.7),Salix caprea (0.4), andTilia cordata (0.9).Twelve species of phytoseiid mites were found, of which ten occurred on unsprayed apple trees. The most widely distributed species on apple trees werePhytoseius macropilis (in 79% of unsprayed samples),Euseius finlandicus (74%),Paraseiulus soleiger (53%),Paraseiulus triporus (37%),Amblyseius canadensis (26%) andAnthoseius rhenanus (26%). The highest densities on apple trees were found in populations ofE. finlandicus (mean 0.7 mites/leaf),Ph. macropilis (0.5) andA. canadensis (0.5). On sprayed apple trees,E. finlandicus, Pa. soleiger andPh. macropilis occurred most commonly, but their mean densities were under 0.1/leaf. Almost no phytoseiids were found in orchards sprayed with oxydemetonmethyl before blooming of apple.On other plants,E. finlandicus occurred most commonly (on 33 plant species) and in the highest densities, followed byPh. macropilis (14),Pa. soleiger (12),Pa. triporus (12) andAn. rhenanus (7).Seiulus aceri andParaseiulus talbii were identified as new phytoseiid species in Finland. It is concluded that deciduous trees and bushes in forest margins around orchards can serve as important reservoirs for phytoseiid mites, and that the dominant species in these plants would migrate into and colonize the orchards if the use of harmful chemicals were restricted.     

Elevated CO<Subscript>2</Subscript> reduces sap flux in mature deciduous forest trees

We enriched in CO₂ the canopy of 14 broad-leaved trees in a species-rich, ca. 30-m-tall forest in NW Switzerland to test whether elevated CO₂ reduces water use in mature forest trees. Measurements of sap flux density (J_S) were made prior to CO₂ enrichment (summer 2000) and throughout the first whole growing season of CO₂ exposure (2001) using the constant heat-flow technique. The short-term responses of sap flux to brief (1.5–3 h) interruptions of CO₂ enrichment were also examined. There were no significant a priori differences in morphological and physiological traits between trees which were later exposed to elevated CO₂ (n=14) and trees later used as controls (n=19). Over the entire growing season, CO₂ enrichment resulted in an average 10.7% reduction in mean daily J_S across all species compared to control trees. Responses were most pronounced in Carpinus, Acer, Prunus and Tilia, smaller in Quercus and close to zero in Fagus trees. The J_S of treated trees significantly increased by 7% upon transient exposure to ambient CO₂ concentrations at noon. Hence, responses of the different species were, in the short term, similar in magnitude to those observed over the whole season (though opposite because of the reversed treatment). The reductions in mean J_S of CO₂-enriched trees were high (22%) under conditions of low evaporative demand (vapour pressure deficit, VPD <5 hPa) and small (2%) when mean daily VPD was greater than 10 hPa. During a relatively dry period, the effect of elevated CO₂ on J_S even appeared to be reversed. These results suggest that daily water savings by CO₂-enriched trees may have accumulated to a significantly improved water status by the time when control trees were short of soil moisture. Our data indicate that the magnitude of CO₂ effects on stand transpiration will depend on rainfall regimes and the relative abundance of the different species, being more pronounced under humid conditions and in stands dominated by species such as Carpinus and negligible in mono-specific Fagus forests.     

Partial age-specific life tables for Monochamus titillator in Dendroctonus frontalis infested loblolly pines

Partial age-specific life tables were constructed for Monochamus titillator(Fabricius) (Coleoptera: Cerambycidae) in Dendroctonus frontalisZimmermann (Coleoptera: Scolytidae) infested loblolly pine (Pinus taedaL.) trees. Successive life stages including egg, early larvae, mid-stage larvae, late larvae, and adult emergence were sampled within six sample trees. Generation mortality ranged from 60.94% to 98.61% in sample trees. Highest mortality typically occurred to eggs and mid-stage larvae. Possible mortality factors included resinosis, predaceous beetles, parasitoids, and woodpeckers. Dendroctonus frontalisbrood stages were determined for consecutive M. titillatorsampling. Monochamus titillatorand D. frontaliscoexisted and likely interacted in the phloem of host trees for at least 20 days.     

Growth and crown efficiency of height repressed lodgepole pine; are suppressed trees more efficient?

Leaf area, crown projection area and growth over the last 5 years were measured to assess growth efficiency (GE) and crown efficiency (CE) of dominant (D), codominant (CD) and suppressed (SP) trees growing in height-repressed (P sites) and normally developing (M sites) lodgepole pine stands. Leaf area index (LAI), hydraulic characteristics, and needle nutrient concentrations were also measured. Volume growth of P site trees between 1994 and 1999 was 46% that of M site trees. Volume growth was closely associated with both hydraulic supply capacity (Q*) and leaf area. Height repression was not associated with lower GE, but P site trees had CE that was 24.5% lower than M site trees. Average GE of D and CD trees was 28% lower than that of SP trees, while mean CE for the D trees was 46% greater than that of CD, and 80% greater than for SP trees. Between M and P sites, canopy LAI and Q* per unit leaf area did not differ. Needle nitrogen (N) concentrations of M site trees were 7.6% greater than for P site trees. SP tree needles had the highest concentration of N and phosphorus. The nutrient advantage enjoyed by SP trees presumably allowed them to maintain higher GE for a given Q*/A_l. The fastest growing trees were the large D and CD trees from M sites. As LAI did not differ between sites, height repression on P sites may be a result of total leaf area being distributed among too many small trees.     

Integrated responses of hydraulic architecture, water and carbon relations of western hemlock to dwarf mistletoe infection

Dwarf mistletoe (Arceuthobium spp.) is a hemiparasite that is said to be the single‐most destructive pathogen of commercially valuable coniferous trees in many regions of the world. Although its destructive nature is well documented in many respects, its effects on the physiology of its host are poorly understood. In the present study, water and carbon relations were characterized over a range of scale from leaf to whole tree in large (40‐ to 50‐m‐tall) individuals of western hemlock (Tsuga heterophylla (Raf.) Sarg.) that were either heavily infected, or uninfected with hemlock dwarf mistletoe (Arceuthobium tsugense). Specific hydraulic conductivity (k_s) of infected branches was approximately half that of uninfected branches, yet leaf‐specific conductivity (k_L) was similar because leaf area : sapwood area ratios (A_L : A_S) of infected branches were lower. Pre‐dawn and minimum leaf water potential and stomatal conductance (g_s) were similar among infected and uninfected trees because adjustments in hydraulic architecture of infected trees maintained k_L despite reduced k_s. Maximum whole‐tree water use was substantially lower in infected trees (approximately 55 kg d^?1) than in uninfected trees (approximately 90 kg d^?1) because reduced numbers of live branches in infected trees reduced whole‐tree A_L : A_S in a manner consistent with that observed in infected branches. Maximum photosynthetic rates of heavily infected trees were approximately half those of uninfected trees. Correspondingly, leaf nitrogen content was 35% lower in infected trees. Foliar δ¹³C values were 2.8‰ more negative in infected than in uninfected individuals, consistent with the absence of stomatal adjustment to diminished photosynthetic capacity. Adjustments in hydraulic architecture of infected trees thus contributed to homeostasis of water transport efficiency and transpiration on a leaf area basis, whereas both carbon accumulation and photosynthetic water use efficiency were sharply reduced at both the leaf and whole‐tree scale.