Assessing the above‐ground biomass of a complex tropical rainforest using a canopy crane

Abstract Current estimates of the total biomass in tropical rainforests vary considerably; this is due in large part to the different approaches that are used to calculate biomass. In this study we have used a canopy crane to measure the tree architectures in a 1 ha plot of complex mesophyll vine forest at Cape Tribulation, Australia. Methods were developed to measure and calculate the crown and stem biomass of six major species of tree and palm (Alstonia scholaris (Apocynaceae), Cleistanthus myrianthus (Euphorbiaceae), Endiandra microneura (Lauraceae), Myristica insipida (Myristicaceae), Acmena graveolens (Myrtaceae), Normanbya normanbyi (Arecaceae)) using the unique access provided by the crane. This has allowed the first non‐destructive biomass estimate to be carried out for a forest of this type. Allometric equations which relate tree biomass to the measured variable ‘diameter at breast height’ were developed for the six species, and a general equation was also developed for trees on the plot. The general equation was similar in form to equations developed for tropical rainforests in Brazil and New Guinea. The species equations were applied at the level of families, the generalized equation was applied to the remaining species which allowed the biomass of a total of 680 trees to be calculated. This has provided a current estimate of 270 t ha⁻¹ above‐ground biomass at the Australian Canopy Crane site; a value comparable to lowland rainforests in Panama and French Guiana. Using the same tree database seven alternative allometric equations (literature equations for tropical rainforests) were used to calculate the site biomass, the range was large (252–446 t ha⁻¹) with only three equations providing estimates within 34 t ha⁻¹ (12.5%) of the site value. Our use of multiple species‐specific allometric equations has provided a site estimate only slightly larger (1%) than that obtained using allometric equations developed specifically for tropical wet rainforests. We have demonstrated that it is possible to non‐destructively measure the biomass in a complex forest using an on‐site canopy crane. In conjunction the development of crown maps and a detailed tree architecture database allows changes in forest structure to be followed quantitatively.     

SHOREBIRD HABITAT USE AND NEST-SITE SELECTION IN THE PLAYA LAKES REGION

Abstract: Wetlands in the Playa Lakes Region (PLR) provide important habitats for wintering waterfowl, cranes, and both migrant and breeding shorebirds. Playa Lakes Region wetlands experience naturally fluctuating hydroperiods but are exposed to anthropogenic stresses, which are exacerbated during summer and may influence PLR wetland occupancy and selection by breeding shorebirds. We examined wetland-scale habitat use and nest-site selection of the 4 dominant shorebirds (American avocets [Recurvirostra americana], black-necked stilts [Himantopus mexicanus], killdeer [Charadrius vociferus], snowy plovers [C. alexandrinus]) nesting in playas, saline lakes, and in both created and riparian wetlands in the PLR of Texas, USA. All 4 species nested in saline lakes. Only avocets and killdeer nested in playas, and snowy plovers nested in riparian wetlands. No nests were found in created wetlands. Wetland habitat changed (P < 0.001) during the breeding season, while water habitats generally decreased. Used (i.e., shorebirds found nesting) wetlands had more (P < 0.05) mudflats than non-used (i.e., shorebirds not found nesting) wetlands, which had more (P < 0.05) dry habitats. Used and non-used wetlands had similar (P > 0.05) amounts of water habitats. Nests were located close to vegetation on bare dry ground and dry ground with vegetation. Because water is ephemeral in PLR wetlands, shorebirds must select—in a somewhat predictive manner upon arrival—wetlands with suitable nest-site and brood-rearing habitat. Although surface water is necessary for nesting, its presence is not adequate for delineating suitable PLR wetland habitat for breeding shorebirds. Our findings that created wetlands cannot compensate for regional wetland losses in habitat or function highlights the need for conservation of natural PLR wetlands     

基于线粒体COI基因的大蚊属Tipula系统发育及长角大蚊亚属Tipula (Sivatipula)分类地位初步研究(双翅目:大蚊总科)

大蚊属Tipula Linnaeus,1758是大蚊科中种类最多的属,目前其单系性尚未得到全面验证.此外,长角大蚊亚属Tipula (Sivatipula) Alexander,1964因其极长的触角以及独有的精子泵结构,明显不同于大蚊属其他亚属,使其亚属的分类地位存在争议.本研究基于COI序列对19个大蚊属物种及5个其他属物种进行了系统发育分析,并计算了物种间的遗传距离.研究结果表明:(1)邻接树(NJ)和最大似然树(ML)均显示长角大蚊亚属与大蚊属其他亚属未形成单系,大蚊属的单系性没有得到支持;(2)基于遗传距离和系统发育分析并结合形态信息,结果显示长角大蚊亚属独立于大蚊属内其他亚属,应将其提升为属级分类单元.     

北京野鸭湖湿地自然保护区越冬灰鹤觅食栖息地选择研究

2006年12月～2007年2月,采用秩变换分析法对北京野鸭湖湿地自然保护区越冬灰鹤群的觅食栖息地选择规律进行了研究.在保护区18种土地利用类型中,灰鹤的觅食柄息地主要为玉米地、沼泽草甸、水库冰面和草场等4种.越冬灰鹤对玉米地的选择性最高,草场的选择性最低,说明北京地区越冬灰鹤对人类活动的依赖性很大.同时发现,烧荒、翻地等耕作方式会大大降低食物的可获得性,影响灰鹤的觅食效率.     

Specialization of rainforest canopy beetles to host trees and microhabitats: not all specialists are leaf‐feeding herbivores

Reliable estimates of host specificity in tropical rainforest beetles are central for an understanding of food web dynamics and biodiversity patterns. However, it is widely assumed that herbivores constitute the majority of host specific species, and that most herbivore species feed on leaves. We tested the generality of this assumption by comparing both plant host‐ and microhabitat‐specificity between beetle communities inhabiting the foliage (flush and mature), flowers, fruit, and suspended dead wood from 23 canopy plant species in a tropical rainforest in north Queensland, Australia. Independent of host tree identity, 76/77 of the most abundant beetle species (N ≥ 12 individuals) were aggregated on a particular microhabitat. Microhabitat specialization (measured by S_m and Lloyd's indices) was very high and did not differ between flower and foliage communities, suggesting that each newly‐sampled microhabitat has a large additive effect on total species richness. In accordance with previous studies, host specificity of foliage‐inhabiting beetles was most pronounced among herbivorous families (Curculionidae, Chrysomelidae). By contrast, host specificity among flower‐visitors was equally high among herbivorous and nonherbivorous families (e.g. Nitidulidae, Staphylinidae, Cleridae). Effective specialization (F_T) measures showed that traditional correction factors used to project total species richness in nonherbivorous groups fail to fully capture diversity in the flower‐visiting beetle fauna. These results demonstrate that host specialization is not concentrated within folivores as previously assumed. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 215–228.     

Species conservation on human-dominated landscapes: the case of crowned crane breeding and distribution outside protected areas in Uganda

Species primarily dependent on habitats outside protected areas have to cope with the direct pressure of human utilization or harassment, and the indirect pressure of habitat modification. In Uganda, wetlands mainly used by cranes occur mostly outside protected areas. The country's wetlands are however under heavy modification, and this and other pressures are thought to have reduced crane populations to 10–30% of the number in the early 1970s. From January 2005 to January 2006, we assessed the status of crane breeding and distribution in the country. Breeding and foraging sites were assessed through a nationwide newspaper survey, and visits to wetlands. We established occurrence of 21 nests during the study period, and crane use of 27 out of 30 districts surveyed. Crane harassment and trapping were common during breeding, as was crop damage by cranes. This is the first attempt to show the distribution of crane breeding outside protected areas throughout the country. In addition to maintaining suitable breeding habitat, survival of cranes in Uganda lies in part in community engagement and punishing crimes related to hunting and destruction of nests.     

The vascular epiphytes of a lowland forest in Panama—species composition and spatial structure

We conducted a comprehensive census of the vascular epiphytes in a lowland forest in Panama by means of a canopy crane. In 0.4 ha of ca. 40-m tall forest, 103 species of vascular epiphytes with 13,099 individuals were found. The orchids were the most important family both in species and individual numbers, accounting alone for >40% of all species and >50% of all individuals. There was a clear vertical segregation of species with a concentration at intermediate heights: more than 50% of all individuals were found between 15 m and 25 m above ground. Tree species identity, tree size and the position of a tree in the forest (“space”) all influenced species composition. However, none of the two environmental variables nor space alone explained more than 10% of the total variation in epiphyte assemblages in several canonical correspondence analyses. By far the largest proportion of the observed variation remained unexplained and is arguably due to mere chance. In the future, our results will be used as a baseline data-set for the direct observation of the long-term dynamics in a diverse epiphyte community.     

Comparison of lepidopteran larval communities among tree species in a temperate deciduous forest, Japan

Abstract.  1. The enormous diversity of phytophagous insects in forest canopies is hypothesised to be supported by the number of herbivorous species per host tree species or host specificity. It is therefore necessary to examine the effect of host plant species on compositional changes in the herbivore communities.
2. The lepidopteran larval communities were examined in the canopies of 10 tree species in a temperate deciduous forest of Japan. The phylogeny and leaf flush phenology of host plant species were taken into account as factors affecting the herbivore community assembly.
3. Examination of seasonal changes in the larval community structures on each tree species showed that larval species richness, abundance, and evenness decreased significantly from spring to summer. Larval species richness and abundance were characterised by family-level phylogenetic differences among tree species, whereas evenness was determined at a higher taxonomic level.
4. Compositional changes in the larval communities among tree species showed a remarkable pattern, with a phylogenetic effect at a high taxonomic level in spring, similar to evenness, but a phenological effect in summer. This suggests that host specificity could support the lepidopteran larval diversity in spring.
5. These results suggest that the differences in host utilisation of the herbivore, which reflects the phylogenetic effect of the host plants, can be important as a factor affecting the diversity of lepidopteran larval communities in temperate forests.     

小兴安岭白头鹤繁殖习性初报

白头鹤(Grus monacha)仅繁殖于俄罗斯的远东地区和中国的小兴安岭森林沼泽湿地,越冬于日本南部、韩国南部沿海和中国长江中下游(Col-lar,2001),是国家一级保护野生动物,被中国濒危动物红皮书列为濒危物种,I UCN(1994,2001)列为易危(VU)物种,并列入CITES附录Ⅰ中(郑光美、王岐山     

Factors affecting captive whooping crane egg fertility: A retrospective analysis

The whooping crane (Grus americana) has been managed in captivity since the 1960s following a substantial genetic bottleneck in the wild population. Through major ex situ conservation efforts, there are 158 whooping cranes managed in North American institutions and chicks are released annually into the wild. Current reintroduction goals for the whooping crane however, are impeded by poor reproduction within the ex situ population, in part because of low egg fertility. Development of improved management techniques to overcome low egg fertility requires a better understanding of factors that influence egg fertility. We collected data for eggs laid at Patuxent Wildlife Research Center from 2005–2014 (n = 438 eggs; n = 23 pairs). We constructed 5 sets of generalized linear mixed-models, with a Bernoulli-distributed response variable (fertile or infertile), to address the effects of egg-specific variables (month laid, sequence, and clutch order of the egg), life-history events of the male and female (age, rearing method, wing condition, age at first pairing, age at current pairing, and female age at first laying), pair-specific characteristics (kinship, years paired, chick-rearing experience, and previous pairings), and captive management decisions (inclusion in the artificial insemination program and pair experience chick-rearing) on the probability of egg fertility. Our results indicate that female-specific factors (especially age, age at current pairing, and wing status) and pair-specific factors of kinship, chick-rearing experience, copulation, and inclusion in the artificial insemination program influenced fertile egg production. Specifically, the younger a female is when paired with her current social mate, the higher probability that her eggs will be fertile. Furthermore, high kinship reduced fertility, whereas chick-rearing experience and artificial insemination of females with a donor male other than her social mate increased fertility. Further research on mate selection and reproductive mechanisms is needed to better understand egg laying and egg fertility in the whooping crane. © 2019 The Wildlife Society.