Limited genetic differentiation of Mycetomoellerius mikromelanos in Parque National Soberanía,Panama: Implications for queen dispersal

The coevolutionary relationship between fungus-growing ants (Formicidae: Attini: Attina) and their symbionts has been well studied in the Panamanian rain forests. To further understand the ecological context of these evolutionary relationships, we have examined the population-genetic structure of the fungus-growing ant species Mycetomoellerius mikromelanos Cardenas, Schultz, Adams 2021 in the Panama Canal Zone. We specifically investigated the presence of population structure, the significance of geographic features (i.e., creeks) limiting gene flow, and relatedness between ant colonies. To accomplish this, we genotyped 85 ant colonies from nine creeks across an approximately 30 km transect in Parque National Soberanía, Panama, using double-digest restriction-site-associated DNA sequencing. We did not find distinct population structure using two genetic clustering methods; however, we did detect an effect of isolation by distance. Furthermore, related colonies were frequently detected on the same creek or neighboring creeks, and some at further geographic distances. Collectively, these findings demonstrate that new colonies tend to establish on natal creeks and occasionally on distant creeks following long-distance dispersal events. We discuss how population-genetic patterns reveal the natural history of M. mikromelanos in Parque National Soberanía and how these results fit into the context of fungus-growing ant mutualisms. Abstract in Spanish is available with online material.     

Plenty of rooftops with few neighbours occupied by young breeding Yellow-legged Gulls (Larus michahellis): Does this occur at the expense of their health condition?

Gulls, as largely flexible opportunistic individuals, have been increasingly breeding in many cities around the world, but it is still unclear whether urban habitats are of equal or higher quality than traditional natural habitats or represent an ecological trap with immediate reproductive benefits but longer-term detrimental consequences to health. Here we present a study of breeding parameters (nest density, egg dimensions, clutch size, hatching success and adult body condition) and physiological parameters (erythrocyte sedimentation rate, heterophil/lymphocyte ratio, haemoglobin concentration and measurements of oxidative stress) as indicators of the general health condition of Yellow-legged Gull Larus michahellis adults and chicks from natural and urban colonies. Yellow-legged Gulls in the largest urban area (Porto) laid smaller eggs and clutches, showed a significantly lower occurrence of inflammatory processes in chicks, and showed a slower early chick growth than in the natural colony of Deserta. This suggests that urban gulls might be facing important trade-offs between the advantages of breeding in lower density urban colonies, with fewer intraspecific interactions and a lower disease transmission probability, and the disadvantages of having an anthropogenic diet usually lower in nutritional value.     

Frog call transmission in forestry monocultures: Are there drawbacks?

Anuran males emit advertisement calls for the purpose of attracting females and repelling conspecific males. Call transmission is influenced by the acoustics of the propagation environment, including vegetation. Thus, forestry monocultures of non-native trees represent artificial environments that could modify call transmission. These monocultures have substituted large areas of Atlantic Forest in southern Brazil, representing a conservation challenge. Considering this context, we hypothesized that anurans have calls that are less attenuated in their native environment than in forest plantations. To test it, we performed sound transmission experiments using calls of three anuran species native to southern Brazil: Boana bischoffi, B. leptolineata, and Hylodes meridionalis. We compared sound attenuation between the native forest and forestry monocultures (Eucalyptus sp. and Pinus sp. forests), and included distance from the sound source, air temperature, humidity, and vegetation density as cofactors in linear mixed models. Our results show that the advertisement calls of the two tree frogs (Boana) attenuate less in tree plantations than in native forests, while the third species shows either no differences or less attenuation in native forests. Our results can be understood according to differences in natural history and microhabitat use among the studied species. The two tree frog species vocalize perched from vegetation so their calls become better transmitted in forestry monocultures, which have fewer trees than the native forest. On the other hand, H. meridionalis calls from rocks on streams and the propagation is finely tuned to this peculiar microhabitat. We discuss the conservation implications of our findings for anurans and for the Atlantic Forest. Abstract in Portuguese and Spanish are available with online material.     

Population dynamics of japanese serow in relation to social organization and habitat conditions. I. Stability of Japanese serow density in stable habitat conditions

The density of a Japanese serow (Capricornis crispus) population, which has been in stable habitat conditions and free from hunting and predation, was investigated by direct observation of serows at Kusoudomari (336 ha), Wakinosawa village, Aomori Prefecture, Japan, during 1977–89. The vegetation, composed of mature mixed forest ofThujopsis with deciduous trees (43.2%), secondary forest of deciduous trees (23.4%) and a plantation of coniferous trees (30.0%) showed little change during the study period. The serows were counted 17 times each winter for 14 consecutive years. The serow population maintained a stable density with a mean of 12.5 individuals km⁻² (SD=1.4) ranging from 8.6 to 14.6 km⁻². The ratio of the proportion of kids (<1 year old) to serows more than 1 year old decreased, but density did not decrease during the study period. Though extremely severe winters with heavy snowfall in 1984–86 caused a decline in serow density, the density recovered within a few years. It was considered that the stability of the serow density resulted mainly from the stable food supply and the lack of human disturbance, such as forest cutting in the habitat. Stable population density for a long period is probably related to the social organization of the serow.     

Mammal use of riparian corridors in semi-arid Sonora,Mexico

Wildlife populations in semi-arid regions are increasingly challenged by human activities and dependent on the connectivity of riparian corridors for access to surface water. The Madrean Archipelago is a biodiversity hotspot along the arid United States–Mexico borderlands that support both Neotropical and Nearctic wildlife. Infrastructure development (e.g., the border wall and the expansion of Mexican Federal Highway 2) in this region inhibits wildlife movement along the transnational mountain archipelago by disconnecting habitat. To explore the relationship between habitat variables and mammal use of riparian corridors in northern Sonora, Mexico, we collected data from 19 motion-sensitive cameras between October 2018 and April 2019 and used single-season occupancy models and Royle-Nichols abundance estimation models to analyze our data. We recorded 21 species of mammals, including the first sighting of jaguar (Panthera onca) in this region in 25 years. River characteristics (distance from river, riparian corridor width, water availability), remoteness (distance from highway, productivity, elevation), and topographic variety (vertical elevation difference) influenced patterns of occupancy probability and estimated abundance of mammals >1 kg, but the strength and direction of these relationships varied by species. Additionally, intermittently wet desert washes were comparable in species richness to the perennial system. These results highlight the importance of examining physical and biological aspects of habitat. This is especially true when identifying corridors where mitigation structures should be placed to improve wildlife connectivity in biodiversity hotspots like the Madrean Archipelago and semi-arid ecosystems worldwide.     

镇海棘螈产卵场微生境选择

镇海棘螈(Echinotriton chinhaiensis)为国家一级重点保护野生动物,其种群面临着生境退化及丧失的重要威胁。产卵是决定镇海棘螈种群数量增长的关键环节之一,了解其产卵选择的微生境偏好可以更有针对性地保护该物种。本研究旨在确定影响镇海棘螈产卵场微生境选择的关键环境变量,同时为该物种的产卵生境保护、改造和重建提供科学基础。本文于2021年3-5月(繁殖期)在浙江省宁波市北仑区林场对镇海棘螈产卵位点(n=105)与非产卵位点(n=70)处的18个微生境变量进行调查。采用拟合优度卡方检验判断3种无序分类变量的差异性,并利用生境喜好系数对生境选择性进行分析。采用二元逻辑斯蒂回归模型对15个数值型变量进行分析,确定影响镇海棘螈产卵微生境选择的关键变量。结果显示镇海棘螈繁殖期间对产卵场微生境有明显偏好,通常产卵于朝向水坑、落叶层较厚(5.19±0.18 cm)、坡度较陡(18.64°±1.18°)和土壤含水量较低(33.51%±1.87%)的土壤基质上。此外,在大型遮蔽物中,镇海棘螈偏好选择体积较小的石块和乔木(2,994.63±316.17 cm³)作为遮蔽...     

The role of reed management and habitat quality on brood parasitism and chick survival of the brood parasitic Common Cuckoo

Despite efforts on ecosystem restoration and management, biodiversity loss remains one of the major environmental concerns of our time. Beyond the focus on threatened species, animals that indicate regional biodiversity hotspots and population trends, such as brood parasites, should also be targeted by conservation actions. We studied how reed habitat quality and management influence brood parasitism rate and offspring survival in Common Cuckoos Cuculus canorus parasitizing nests of Great Reed Warblers Acrocephalus arundinaceus in six reed habitats in an intensive agricultural landscape. Data collected from 45 sites over 13 years showed that the brood parasitism rate was highest on large canals and was positively influenced by the availability of potential perches (Cuckoo vantage points) and the height where host nests were built. Cuckoo chick survival decreased with water depth and was not affected by other factors. Our results suggest that the habitat-dependent detectability of host nests was central in brood parasitism rate and that water level was central in Cuckoo chick survival. Our study shows that a maintenance of intermediate water levels is the most optimal for maintaining Cuckoo populations in intensive agricultural landscapes. Because brood parasites are excellent bioindicators as their presence predicts regional hotspots of taxonomic and functional diversity as well as population trends in bird communities, knowledge on their habitat requirements is relevant in management targeting diverse bird communities.     

Genetic variation in three species in the Lampropholis delicata (Lacertilia: Scincidae) complex

The Lampropholis delicata complex consists of three closely related species, which have very different habitat requirements and geographic distributions. Percentage polymorphism and average heterozygosity per population are lowest in the species with the narrowest habitat requirements. Genetic differentiation between populations is also lowest in this species, which had a very limited and almost continuous distribution. For one species, which occurs in a very wide range of habitats, both natural and disturbed, genetic variability is compared between samples from disturbed and undisturbed habitats. Average heterozygosity is significantly lower in samples from disturbed than in those from undisturbed sites.     

陕西佛坪国家级自然保护区羚牛的容纳量

陕西佛坪国家级自然保护区位于秦岭南坡的中段 ,1998～ 1999年冬季通过分层抽样的方法 ,测定了保护区内羚牛秦岭亚种 (Budorcastaxicolorbedfordi) 10种栖息地类型的单位面积食物资源量和含有的能量 ,估计了越冬区可以利用的总能量。结果表明 ,羚牛越冬区提供的可供羚牛和其它草食动物利用的能量为 (9 877±5 173)× 10 12 J,每只羚牛平均每天需要的能量为 2 6 4 8± 11 88kJ ,整个冬季需要的能量为 4 82 0± 2 16 3× 10 6J ,保护区的羚牛容纳量为 2 0 4 9± 10 37只。考虑到羚牛对空间的需求、保持最佳繁殖状态、其它草食动物种群的需求和保护当地植被等因素 ,建议保护区将羚牛种群的数量控制在 10 0 0只左右.     

Spatial ecology of golden jackal in farmland in the Ethiopian Highlands

The spatial ecology of golden jackal Canis aureus was studied on farmland adjacent to the Bale Mountains National Park in southern Ethiopia during 1998–2000. Three adult and four subadult jackals were captured in leg‐hold traps and radiotagged. The range size of the adult jackals varied from 7.9 to 48.2 km² and the subadults from 24.2 to 64.8 km² . These ranges are the largest recorded for this species. Range overlap of the tagged jackals averaged 54%, which, in conjunction with observations of associations between individuals, suggested that all the tagged jackals belonged to one social group. Tagged jackals were observed alone on 87% of occasions despite the extensive overlap in individual ranges. Pairs consisting of a male and female were the most commonly observed group and larger groups were seen on only five occasions. Jackals in this population appeared less gregarious than observed elsewhere. The jackals used all the habitats available to them, particularly at night when they foraged in Artemesia and Hypericum bush and farmland. During the day they were more frequently found in Hagenia and Juniper woodland and their diurnal resting sites were characterized by thick cover. This is the first detailed study of golden jackals in a human‐modified landscape in Africa and further demonstrates the flexibility in behaviour and ecology exhibited by this species throughout its range.