Demographics of the European hare (Lepus europaeus) in the Mediterranean climate zone of Australia

Demographic parameters of the European hare (Lepus europaeus) in southern Australia were investigated by dissecting hares shot by hunters during each month of the year. Gender, body weight, age, sucking, lactation, weight of the abdominal alimentary canal, weight of the left peri-renal fat body, pregnancy status, presence and counts of placental scars, litter size, and stage of gestation were recorded. From those data, growth rates, age at weaning, age and weight at puberty, date of conception, projected birth date, recruitment, survivorship, and the relationships between lactation and fat stores and alimentary capacity were determined.Fecundity of the southern Australian hares followed the seasonal pattern reported for northern hemisphere populations. However, output was lower per female and particularly per older female. Females began breeding at an earlier age such that recruitment into the southern Australian population was more dependent on females in their first year of life than on older females. Growth rates were comparable with European rates. Although high chill factors were apparently associated with higher leveret mortality, there was paradoxically higher overall mortality during the spring-early summer period of higher plant growth than in the late summer–winter period of lower plant growth and more extreme weather conditions. Fat was accumulated during pregnancy and would act as a buffer against the possibility of inadequate food availability during lactation, but hares increased the capacity of the alimentary canal during lactation and presumably with it their ability to assimilate energy to meet the demands of lactation.     

Better safe than sorry: The response to a simulated predator and unfamiliar scent by the European hare

Predator presence can create a “landscape of fear,” which is defined as the spatially explicit distribution of perceived predation risk as seen by prey. Prey species can alter their behavior and space use as a response to increased predation risk, which might be traded off with energetic requirements. Thus, whether or not an anti-predator behavior is performed might depend on the perceived risk. In this study, we investigated the behavioral and spatial response of the European hare (Lepus europaeus) toward the presence of a predator scent, using red fox (Vulpes vulpes) scat, an unfamiliar control scent (butyric acid), and a true control (no scent). We collected data on hare activity times and behavior using 50 camera trap locations and spatial data using GPS telemetry (30,481 GPS positions of 12 hares). Hares showed spatial anti-predator behaviors within their home range, for example, the local avoidance of areas treated with scent and remaining further from field edges, in response to sympatric predator scent and partly also in response to unfamiliar butyric acid. Conversely, more costly anti-predator behaviors, that is, increased vigilance at the expense of foraging, were only shown in response to the predator scent. Our results suggest that prey species respond flexibly toward scent cues, utilizing less costly anti-predator behaviors independent of the perceived threat, whereas costly anti-predator responses are only used in the presence of “real” threat. Further, our findings emphasize that a combination of camera trap and GPS data can provide detailed information on animal behavior and space use, and caution that interpretation of one data source alone might lead to incomplete conclusions.     

Phylogeography of the brown hare (Lepus europaeus) in Europe: a legacy of south‐eastern Mediterranean refugia?

Aim We analysed the population genetics of the brown hare (Lepus europaeus) in order to test the hypothesis that this species migrated into central Europe from a number of late glacial refugia, including some in Asia Minor. Location Thirty‐three localities in Greece, Bulgaria, Italy, Croatia, Serbia, Poland, Switzerland, Austria, France, Germany, the Netherlands, Spain, the United Kingdom, Turkey and Israel. Methods In total, 926 brown hares were analysed for mitochondrial DNA (mtDNA) variation by restriction fragment length polymorphism (RFLP) performed on polymerase chain reaction‐amplified products spanning cytochrome b (cyt b)/control region (CR), cytochrome oxidase I (COI) and 12S–16S rRNA. In addition, sequence analysis of the mtDNA CR‐I region was performed on 69 individuals, and the data were compared with 137 mtDNA CR‐I sequences retrieved from GenBank. Results The 112 haplotypes detected were partitioned into five phylogeographically well‐defined major haplogroups, namely the ‘south‐eastern European type haplogroup’ (SEEh), ‘Anatolian/Middle Eastern type haplogroup’ (AMh), ‘European type haplogroup, subgroup A’ (EUh‐A), ‘European type haplogroup, subgroup B’ (EUh‐B) and ‘Intermediate haplogroup’ (INTERh). Sequence data retrieved from GenBank were consistent with the haplogroups determined in this study. In Bulgaria and north‐eastern Greece numerous haplotypes of all five haplogroups were present, forming a large overlap zone. Main conclusions The mtDNA results allow us to infer post‐glacial colonization of large parts of Europe from a late glacial/early Holocene source population in the central or south‐central Balkans. The presence of Anatolian/Middle Eastern haplotypes in the large overlap zone in Bulgaria and north‐eastern Greece reveals gene flow from Anatolia to Europe across the late Pleistocene Bosporus land‐bridge. Although various restocking operations could be partly responsible for the presence of unexpected haplotypes in certain areas, we nevertheless trace a strong phylogeographic signal throughout all regions under study. Throughout Europe, mtDNA results indicate that brown hares are not separated into discernable phyletic groups.     

Is the large size of the pinna of the ear of the European hare (Lepus europaeus) due to its role in thermoregulation or in anterior capital shock absorption?

Large pinnae are characteristic of the Leporids, and the pinna is known to have a thermoregulatory role. Another role has been hypothesized for the pinna of Lepus spp., as a part of a suspensory system for the greater portion of the head, absorbing shock that might otherwise interfere with vision during high‐speed locomotion. We compared the lengths of the pinnae of adult European hares Lepus europaeus from the source population in the cooler climate of England with those of the introduced population in the warmer climate of Australia, and we compared the lengths of the pinnae of hares that had grown in cooler weather with those that had grown in warmer weather. There were no significant differences between each of the comparisons, indicating that the size of the pinna is not determined by thermoregulatory requirements at rest. We compared the growth in length of the pinnae and the legs with growth in body mass, and growth in the mass of the pinnae with the masses of the head and the eyeballs, and found support for the suspension hypothesis. We suggest that the rapid growth of the pinna is because visual acuity is a function of absolute eye size, not relative eye size, yet juvenile hares are subject to the same predator pressure as adult hares, and equally need to maximize visual acuity while running at high speeds in dim light. We believe that the large size of the pinna is determined by its role in anterior capital suspension, not in thermoregulation. J. Morphol., 2010. © 2010 Wiley‐Liss, Inc.     

Major histocompatibility complex variation at class II DQA locus in the brown hare (Lepus europaeus)

The major histocompatability complex (MHC) is a multigene family of receptors that bind and present antigenic peptides to T-cells. Genes of the MHC are characterized by an outstanding genetic polymorphism, which is considered to be maintained by positive selection. Sites involved in peptide binding form binding pockets (P) that are collectively termed the peptide-binding region (PBR). In this study, we examined the level of MHC genetic diversity within and among natural populations of brown hare ( Lepus europaeus ) from Europe and Anatolia choosing for analysis of the second exon of the DQA locus, one of the most polymorphic class II loci. We aimed at an integrated population genetic analysis of L. europeaus by (i) correlating MHC polymorphism to genetic variability and phylogenetic status estimated previously from maternally (mtDNA) and biparentally (allozymes, microsatellites) inherited loci; and (ii) comparing full-length exon amino acid polymorphism with functional polymorphism in the PBR and the binding pockets P1, P6 and P9. A substantial level of DQA exon 2 polymorphism was detected with two completely different set of alleles between the Anatolian and European populations. However, the phylogeny of full-length exon 2 Leeu-DQA alleles did not show a strong phylogeographic signal. The presence of balancing selection was supported by a statistically significant excess of nonsynonymous substitutions over synonymous in the PBR and a trans-species pattern of evolution detected after phylogenetic reconstruction. The differentiating patterns detected between genetic and functional polymorphism, i.e. the number and the distribution of pocket variants within and among populations, indicated a hierarchical action of selection pressures.     

A review of vital rates and cause‐specific mortality of elk Cervus elaphus populations in eastern North America

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Demographic response of snake-necked turtles correlates with indigenous harvest and feral pig predation in tropical northern Australia

Species that mature late, experience high levels of survival and have long generation times are more vulnerable to chronic increases in mortality than species with higher fecundity and more rapid turnover of generations. Many chelonians have low hatchling survival, slow growth, delayed sexual maturity and high subadult and adult survival. This constrains their ability to respond quickly to increases in adult mortality from harvesting or habitat alteration. In contrast, the northern snake-necked turtle Chelodina rugosa (Ogilby 1890) is fast-growing, early maturing and highly fecund relative to other turtles, and may be resilient to increased mortality. Here we provide correlative evidence spanning six study sites and three field seasons, indicating that C. rugosa is able to compensate demographically to conditions of relatively low subadult and adult survival, caused by pig Sus scrofa (Linnaeus 1758) predation and customary harvesting by humans. Recruitment and age specific fecundity tended to be greater in sites with low adult and subadult survival (and thus reduced densities of large turtles), owing to higher juvenile survival, a smaller size at onset of maturity and faster post-maturity growth. These patterns are consistent with compensatory density-dependent responses, and as such challenge the generality that high subadult and adult survival is crucial for achieving long-term population stability in long-lived vertebrates such as chelonians. We posit that long-lived species with 'fast' recruitment and a capacity for a compensatory demographic response, similar to C. rugosa, may be able to persist in the face of occasional or sustained adult harvest without inevitably threatening population viability.     

Biases in the estimation of the demographic parameters of a snowshoe hare population

1. Survival rates and natalities for a population of snowshoe hares in the Yukon were estimated independently of and simultaneously with estimates of population change during the increase phase of a hare cycle.
2. Simple demographic models are used to show that even though the estimated survival rates and natalities were high relative to previously published estimates, the observed demographic parameters are unable to explain the extent of population increase, and we conclude that some of these parameters must be underestimates.
3. A sensitivity analysis is used to examine the potential influence of changes in these demographic parameters on the population growth rate. During most years of the hare cycle the population growth rate is potentially most sensitive to changes in juvenile postweaning survival. Only during crash years is adult survivorship likely to be a more important determinant of the rate of population change.
4. Examination of previously published data sets on two full population cycles suggests that while survival rates are positively correlated with population growth rates, their incorporation into demographic models results in frequent underestimation of the rate of population increase.     

Demographic Sensitivity of Population Change in Northern Bobwhite

Abstract: The northern bobwhite (Colinus virginianus) is an economically important gamebird that is currently undergoing widespread population declines. Despite considerable research on the population ecology of bobwhites, there have been few attempts to model population dynamics of bobwhites to determine the contributions of different demographic parameters to variance of the finite rate of population change (Λ). We conducted a literature review and compiled 405 estimates of 9 demographic parameters from 49 field studies of bobwhites. To identify demographic parameters that might be important for management, we used life-stage simulation analyses (LSA) to examine sensitivity of Λ to simulated variation in 9 demographic parameters for female bobwhites. In a baseline LSA based on uniform distributions bounded by the range of estimates for each demographic parameter, bobwhite populations were predicted to decline (Λ = 0.56) and winter survival of adults made the greatest contribution to variance of Λ (r² = 0.453), followed by summer survival of adults (r² = 0.163), and survival of chicks (r² = 0.120). Population change was not sensitive to total clutch laid, nest survival, egg hatchability, or 3 parameters associated with the number of nesting attempts (r²<0.06). Our conclusions were robust to alternative simulation scenarios, and parameter rankings changed only if we adjusted the lower bounds of winter survival upwards. Bobwhite populations were not viable with survival rates reported from most field studies. Survival rates may be depressed below sustainable levels by environmental conditions or possibly by impacts of capture and telemetry methods. Overall, our simulation results indicate that management practices that improve seasonal survival rates will have the greatest potential benefit for recovery of declining populations of bobwhites.     

Population dynamics of king eiders breeding in northern Alaska

The North American population of king eiders (Somateria spectabilis) has declined by more than 50% since the late 1970s for unknown reasons. King eiders spend most of their lives in remote areas, forcing managers to make regulatory and conservation decisions based on very little information. We incorporated available published estimates of vital rates with new estimates to build a female, stage-based matrix population model for king eiders and examine the processes underlying population dynamics of king eiders breeding at 2 sites, Teshekpuk and Kuparuk, on the coastal plain of northern Alaska and wintering around the Bering Sea (2001–2010). We predicted a decreasing population (λ = 0.981, 95% CI: 0.978–0.985), and that population growth was most sensitive to changes in adult female survival (sensitivity = 0.92). Low duckling survival may be a bottleneck to productivity (variation in ducking survival accounted for 66% of retrospective variation in λ). Adult survival was high (0.94) and invariant ( = 0.0002, 95% CI: 0.0000–0.0007); however, catastrophic events could have a major impact and we need to consider how to mitigate and manage threats to adult survival. A hypothetical oil spill affecting breeding females in a primary spring staging area resulted in a severe population decline; although, transient population dynamics were relatively stable. However, if no catastrophic events occur, the more variable reproductive parameters (duckling and nest survival) may be more responsive to management actions. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.     

新疆濒危野生樱桃李的种群结构与动态

为了解野生樱桃李种群结构和种群生态现状,采用“空间序列代替时间变化”的方法,对新疆天然分布区内的野生樱桃李不同种群的径级结构、冠幅结构及株高结构进行了分析,运用静态生命表描述了野生樱桃李种群年龄结构的动态变化规律.结果表明,樱桃李天然种群的株高和冠幅结构呈现为一定的衰退趋势,冠幅在总体呈现为近乎对数型的衰减趋势;种群的径级结构趋于稳定型,但种群结构表现出较强的波动性,种群衰退风险较高;同时,不同样地种群因所处微环境等的差异,在径级、株高和冠幅结构上表现出一定差异.野生樱桃李种群的存活曲线接近于B1型(台阶型),说明幼龄的死亡率较高,且不同生活史时期的死亡率差异较大.新疆的野生樱桃李天然种群表现出一定的不稳定性,亟待补充低龄级的个体,并减少对成年树的砍伐破坏,从而为种群的保育和恢复提供保障.