Habitat Use and Mobility of Two Threatened Coastal Dune Insects: Implications for Conservation

We studied the habitat use and mobility of the Grayling butterfly (Hipparchia semele) and the Blue-Winged Grasshopper (Oedipoda caerulescens), two threatened insects within spatially structured blond and grey dunes in a nature reserve along the Belgian coast. Although both species occur in the same biotope, H. semele were more abundant in open, dynamic sites with a relatively high amount of bare sand, while O. caerulescens preferred sheltered, more stable environments with a lower amount of bare sand. Unlike H. semele, substrate use varied in accordance to body colouration in O. caerulescens, especially on cold days, with light-coloured animals being more abundant on sand and dark-coloured animals more abundant on moss. During a mark-recapture-study, we marked 493 Grayling butterflies and 1289 Blue-Winged Grasshoppers. On average, both sexes of H. semele were equally mobile (about 150 m/day; maximum recorded distance of about 1700 m) while male O. caerulescens were significantly more mobile than females (daily average 47 vs. 5 m; maximum distances observed for O. caerulescens were about 800 m). The importance of habitat heterogeneity (within and among patches) and the consequences of habitat use and mobility of both species for the conservation of typical coastal dune habitats are discussed. The complementary use of species-specific information to site-based management measures is advocated.     

Roosting site selection in the endangered damselfly, Coenagrion mercuriale, and implications for habitat design

A successful conservation strategy for an insect species should address the habitat requirements of all life stages and all activities performed by those life stages. In this paper the night-time roosting habitat and behaviour of the endangered damselfly Coenagrion mercuriale (Odonata: Coenagrionidae) was investigated by marking damselflies with UV fluorescent paint. Night-time observations revealed that individuals did not roost together and those that were recorded on more than one occasion did not return to the same spot each night. There was no apparent preference for roosting close to the watercourses. C. mercuriale roosted towards the top of the vegetation and this vegetation was considerably taller than the mean height of the vegetation in the study area. Adults were strongly associated with two tussock-forming monocots, Juncus inflexus and Deschampsia cespitosa. Differences in the abundance of these plants were shown to result in large differences in the numbers of C. mercuriale roosting in different parts of the site. The importance of providing these structural elements of habitat as part of a wider conservation strategy for this species is discussed.     

Vegetation analysis in colonies of an endangered rodent, the Cabrera vole (Microtus cabrerae), in southern Portugal

The Cabrera vole (Microtus cabrerae) is a threatened rodent endemic in the Iberian Peninsula with a patchy distribution and specific microhabitat requirements. This aim of this study was to document the composition of plant communities in habitats of Cabrera vole colonies in southern Portugal. Differences observed in plant species composition were also compared with vegetation structure, taxonomic and life form groups, species and group diversity, disturbance, topography and soil properties. Vegetation was sampled between March and July 2004, in 26 colonies occurring in five geographical areas. Grasses were the most abundant, common and diverse family in the colonies, and the perennial grass Agrostis castellana was present in 92% of colonies, with a mean cover of 16% of the site. Other frequently occurring species were Briza maxima (85%), Vulpia myuros (85%), Gaudinia fragilis (81%), Leontodon spp. (81%), Avena barbata (77%), Bromus hordeaceus (77%) and Tolpis barbata (77%). Colonies were classified in eight vegetation groups that included meadows, tall perennial grasslands, manured meadows with tall sedges, annual grasslands and ruderal and nitrophilous grasslands. Main gradients associated with composition differences were grass richness, annual and perennial grass cover, vegetation structure (herbaceous vegetation height), soil properties (texture and moisture), disturbance (ruderal species) and colony dimensions (area). Results suggest that the Cabrera vole is able to exploit a wide variety of grasslands, with a varying degree of ecological disturbance. Meadows and perennial grassland communities seem to be higher-quality microhabitats for voles.     

Estimating disturbance effects from military training using developmental instability and physiological measures of plant stress

We used developmental instability, water potential, and variable fluorescence to determine if populations of winged sumac (Rhus copallinum) were being negatively effected by military training disturbance. We established nine sites that represented a land-use disturbance gradient with three impact levels (low, medium, and high), the effects mostly due to mechanized infantry training maneuvers. Although mean values of developmental instability, water potential, and variable fluorescence differed significantly among sites, the patterns did not consistently differentiate sites relative to the disturbance gradient. At the population level, some measures of developmental instability and variable fluorescence were positively correlated. All nine sites consisted of habitat mosaics, with the abundance of higher quality habitat patches and canopy gaps closely related to habitat impacts. It may be that R. copallinum is selecting similar micro-environments at all sites and therefore minimizing inter-site variation in stress measures, despite large differences in overall habitat condition. Our results call for caution in developing ecological indicators using the response of physiological and morphological measures from a single plant species.     

The role of the secondary plant compound 2,5-dihydroxymethyl 3,4-dihydroxypyrrolidine as a feeding inhibitor for insects

The cyclic amino alditol 2,5-dihydroxymethyl 3,4-dihydroxypyrrolidine (DMDP) has recently been shown to be an inhibitor of various glucosidases. We have investigated its role as a plant protective chemical against a range of phytophagous insects by examining its effects on development, feeding behaviour and functioning of taste receptors. We have shown that it can inhibit feeding and can be toxic. The mechanisms by which these effects are achieved are discussed in the context of the molecular structure of the compound.

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Résumé Récemment a été mis en évidence le puissant pouvoir inhibiteur de différents glucosidases. Présenté par l'amino-alditol cyclique, 2,5 dihydroxymethyl 3,4 dihydroxypyrrolidine (DMDP), isolé de graines de la légumineuse Lonchocarpus sericeus. Nous avons examiné le rôle de ce composé secondaire dans la stratégie défensive de la plante contre une gamme d'insectes phytophages, à travers son action sur le développement, le comportement alimentaire et le fonctionnement des récepteurs gustatifs. Nous avons montré que DMDP peut inhiber, suivant la dose, la prise de nourriture et, qu'aprs ingestion (par Spodoptera spp), il peut agir comme une toxine. Par suite de sa structure moléculaire, DMDP peut être considéré, non seulement comme l'analogue d'un sucre, mais aussi comme un alcaloïde. Le bilan des résultats de nos expériences suggère que l'efficacité de DMDP comme phagodissuadant, si elle ne provient pas de sa toxicité, découle principalement de ses propriétés d'alcaloïde.

     

Benefit of permanent non-fire refugia for Lepidoptera conservation in fire-managed sites

From the early 1990s through 2005, we conducted butterfly transect surveys annually at the same sites in three regions of Wisconsin. We compared specialist butterfly population indices at three sites where a permanent non-fire refugium (a unit kept unburned through cycles of rotational fire elsewhere in the site) was established during this study to indices at comparison sites (which had consistent management throughout this study) in the same region. At Crex Meadows (12,180 ha), all significant changes in specialist numbers skewed toward relatively higher abundance in the refugium (14 ha, last burned in 1988) during the later period (1998–2005) versus 10 comparison subsites (fire-managed in both periods) than expected from observations in the earlier period (1991–97). The same pattern occurred in the refugium (4 ha) at Bauer-Brockway (125 ha), after the rest of that unit (9 ha) had its first management fire. Population trends were positive in these refugia, while the comparison sites usually had less favorable trends, or otherwise had similar trends. At Muralt Bluff (25 ha), regal fritillaries (Speyeria idalia) were more concentrated in the refugium (3 ha, last burned in 1991) during the earlier period but were more abundant in both periods in the refugium than the other units there (fire-managed in both periods). In the earlier period at Muralt Bluff, this species significantly declined, the opposite trend of comparison sites (which always had never-burned refugia), but significantly increased in the later period, similar to comparison sites. The refugium did not benefit Ottoe skipper (Hesperia ottoe), which declined significantly in the earlier period and was not recorded in the later period. Formerly burned units began functioning as refugia only >6–8 years after last fire and continued to increase in benefit for years after that. In fire-managed and fire-prone sites, we recommend the creation of permanent non-fire refugia for Lepidoptera conservation, placed where the most specialists will benefit and managed unintensively (e.g. mowing) if needed.     

Multiple ice-age refugia in a southern beech of South America as evidenced by chloroplast DNA markers

Chloroplast DNA polymorphisms were analysed to infer the post-glacial history of Nothofagus nervosa (Phil.) Dim. et Mil., a species endemic to South American Temperate Forests. Two hypotheses were postulated to explain the current distribution of the species in relation to the refugia proposed after palynological studies and the time elapsed since Last Glacial Maximum. If refugia were located only in the Coastal Mountains, as pollen records suggests, long-distance dispersal events should be invoked to explain the current occurrence of the species in southern latitudes. The alternative hypothesis is the existence of cryptic refugia in southern latitudes. A total of 26 populations covering the entire geographical range of the species in Chile and Argentina were analysed through PCR–RFLP. Five haplotypes were identified, and a very low intrapopulation variation was observed together with a high gene differentiation (G _ST=0.93). The haplotypes showed a highly structured geographic distribution, separating populations located in the Pacific Coastal Mountains from those coming from the easterly located Andes Mountains. Moreover, among the populations of the Andes Mountains a north–south variation in the distribution of haplotypes was found. The results strongly suggest the persistence of the species in several ice-age refugia. The possible location of such refugia is discussed in combination with the available palynological data.     

Species-area relationship and potential role as a biomonitor of mangrove communities of Malayan mudskippers

The rapid and extensive destruction of mangrove forests and adjacent peritidal ecosystems in the Indo-Pacific region requires the development of efficient management and conservation actions. Mudskippers (Gobiidae: Oxudercinae) are amphibious gobies that are strictly linked to mangrove forests and tropical mudflats. I recorded the presence and habitat distribution of mudskipper species in four mangrove ecosystems along the west coast of Peninsular Malaysia. Different localities host different mudskipper communities, while in each locality species are differentially distributed along the intertidal gradient. At the ecosystem level, I found a significant exponential correlation between sampled area and the species richness of these communities, consistent with the SAR hypothesis. At the habitat level, the presence of a vertical zonation along the intertidal gradient suggests the possibility of using the species living exclusively in higher or lower levels as bioindicators for habitat anthropogenic impact, respectively from the land and from the sea.     

Just how important are structural elements as habitat components? Indications from a declining lycaenid butterfly with priority conservation status

Recently, it has been suggested that habitats for insect herbivores have been too narrowly defined, often on the basis of larval hostplants; in particular, non-consumable resources (called utilities; structural elements) have been ignored. Here, the importance of utility resources for roosting and mate location has been examined in the silver-studded blue butterfly Plebejus argus (L.) (Lycaenidae) on the Great Ormes Head, North Wales, UK. The methods included using dedicated surveys and correspondence analysis applied to behavioural observations in relation to vegetation structure on a transect through a key patch for this metapopulation model species. A substantial and significant bias in roosting (97%) and mating (75%) is found to occur outside hostplant areas on shrubs and rank bunched grasses and forbs. Population density is higher in shrubby areas and shrubs are increasingly occupied during the afternoons and night, during the late flight season and in cloudy, cool and windy weather. These findings suggest that shrubs are a valuable habitat component for this butterfly, at least at this coastal location, and important for their conservation. As scrub growth is inimical to calcicolous grassland, population status will depend on a fine balance between shrub and hostplant cover dependent on grazing and browsing by the indigenous goat, sheep and rabbit populations as well as on controlled cutting and burning. Opportunities exist for increasing population size and distribution on the headland but this will need to be managed carefully. There are also implications for metapopulation dynamics studies; the status of shrubs neighbouring host plant areas switches from that of barriers to resources and refuges.     

TrackBeam, a simple tool for estimating potential exposure to the solar beam underneath tree canopies

A simple tool, TrackBeam, for rapid in situ estimates of potential exposure to the solar beam of objects underneath tree canopies is presented, tested and demonstrated to be useful in insect conservation studies. The tool can be used whenever accurate data on sun exposure is of use e.g., in ecological studies of saproxylic insects. TrackBeam draws upon the principles behind the analysis of hemispherical photographs but its use is much less dependent on the weather at the time of sampling. It may be used for detecting canopy openings in directions corresponding to the solar path. Based on this, periods of time with potential beam exposure and/or the proportion of sky that is not obscured by canopy for objects such as dead wood may be estimated. The results of using TrackBeam compares well between operators and with the corresponding results of analysed hemispherical photographs. Results are presented which show that TrackBeam was successfully used to characterise the habitat light requirements of the saproxylic beetle Melanotus castanipes (Coleoptera: Elateridae).     

An improved method for callus proliferation and regeneration of Fuchsia hybrida

Best callus initiation was obtained when single-node explants of Fuchsia hybrida were incubated in the light on Gamborg B5 medium containing 5×10^-6 M indoleacetic acid and benzylaminopurine at 5×10^-7 M or 10^-6 M. Healthy callus proliferation was maintained in darkness on full-strength B5 medium supplemented with 5×10^-6 M IAA and 5×10^-7 M BAP. Regeneration from callus was obtained in 3 to 6 weeks, using half-strength hormone-free Campbell & Durzan medium.Abbreviations BAP 6-benzylaminopurine - 2,4-D 2,4 dichlorophenoxyacetic acid - IAA indoleacetic acid - IBA indolebutyric acid - NAA -naphthaleneacetic acid - SE standard error     

Long-term persistence of aspen – a key host for many threatened species – is endangered in old-growth conservation areas in Finland

Large, dead and dying European aspens (Populus tremula L.) host many threatened species in Fennoscandian boreal forests. Large aspen trees have mostly disappeared and are being harvested from the managed forests that cover 95% of the forest area in Finland. Due to the small area protected (4.1%), the aspen-associated species may encounter major difficulties in the protected areas if aspen trees disappear due to natural forest succession. The availability of aspens was assessed in the old-growth conservation area network in eastern Finland. We mapped all the living and dead aspens in 15 protected old-growth forests. The total number of counted trees was 32 903 individuals. Current amounts of living (2.7 m³/ha) and especially dead aspens (2.8 m³/ha) in the protected areas were higher than in the surrounding managed forests (1.1 and 0.1 m³/ha for living and dead trees, respectively). However, while saplings (dbh<5 cm) occur in most of the areas (12 individuals/ha on average) they survive poorly and young aspen cohorts (5 cm <dbh<15 cm) are lacking or are very rare. The most likely reason for the poor sapling survival is high browsing pressure by the mammalian herbivores, especially the moose. The moose population has increased many times in Finland during the past decades. The poor regeneration of aspens implies that the value of the old-growth conservation areas for aspen-associated species will face a serious bottleneck within a few decades when the currently middle-aged tree cohorts disappear. If the current high browsing pressure and lack of natural disturbances continue the obligatory aspen-associated species may disappear both locally and regionally from the network of the protected areas.     

Assessing the potential for zinc and cadmium phytoremediation with the hyperaccumulator Thlaspi caerulescens

Thlaspi caerulescens is a Zn and Cd hyperaccumulator, and has been tested for its phytoremediation potential. In this paper we examine the relationships between the concentrations of Zn and Cd in soil and in T. caerulescens shoots, and calculate the rates of Zn and Cd extraction from soil. Using published data from field surveys, field and pot experiments, we show that the concentrations of Zn and Cd in the shoots correlate with the concentrations of Zn and Cd in soils in a log-linear fashion over three orders of magnitude. There is little systematic difference between different populations of T. caerulescens in the relationship between soil and plant Zn concentrations. In contrast, populations from southern France are far superior to those from other regions in Cd accumulation. Bioaccumulation factors (plant to soil concentration ratio) for Zn and Cd decrease log-linearly with soil metal concentration. Model calculations show that phytoremediation using T. caerulescens is feasible when soil is only moderately contaminated with Zn and Cd, and the phytoremediation potential is better for Cd than for Zn if the populations from southern France are used. Recent progress in the understanding of the mechanisms of Zn and Cd uptake by T. caerulescens is also reviewed.     

Floristic and ecological diversity of Ranunculus aquatic habitats in the sub-Atlantic range: implications for conservation

Ranunculus communities have been identified by the European Community Directive on Conservation of Natural and Semi-Natural Habitats as a key habitat in need of protection. The ecological requirements and floristic composition of three Ranunculus communities were investigated in North-Eastern France. We also aimed to determine the relationships between environmental parameters, Ranunculus abundance and species richness. R. fluitans communities clearly differed from the other communities by a higher evenness and species richness and by the occurrence of specific species. In contrast, R. penicillatus and R. peltatus communities displayed similar floristic content. Three different sub-associations were however identified within these communities. If alkalinity was determinant in isolating R. fluitans communities from the other stretches, the ecological ranges of the three communities strongly overlapped while considering parameters linked with other resources or with physical constraints. Further, no significant correlations were highlighted between environmental parameters, Ranunculus abundance and species richness. With respect to conservation, these observations may indicate the particular difficulty in defining each Ranunculus habitat on a European scale, and identify several key points which need to be taken into account when evaluating their status.     

越冬青头潜鸭的栖息地利用和行为时间分配

青头潜鸭(Aythyabaeri)是世界极危级(CR)物种,2018年至今在河南民权黄河故道国家湿地公园均调查到稳定的青头潜鸭越冬种群.研究青头潜鸭对不同栖息地的利用方式及所受干扰有利于该物种的保护管理.本研究分析了越冬期不同栖息地及不同性别青头潜鸭的行为时间分配差异,以及人为干扰对青头潜鸭活动的影响.2020年12月采用焦点取样法对河南民权黄河故道国家湿地公园内青头潜鸭进行行为观察,按照青头潜鸭对栖息地的利用率,将其栖息地类型分为池塘、大水面荷塘和开阔水域.使用单因素方差分析(ANOVA)及t检验比较不同栖息地及性别间差异的显著性.青头潜鸭的主要行为是休息(44.4％)和觅食(34.2％),且在不同栖息地存在显著差异.池塘中的觅食行为占比(50.1％)显著高于大水面荷塘和开阔水域;大水面荷塘中的休息行为占比(63.1％)显著高于池塘和开阔水域.雌雄之间存在一定的行为差异,雌性觅食时间高于雄性,整理行为时间低于雄性,这种差异受栖息地的影响.三种类型栖息地均存在不同程度的人为干扰,池塘中所受干扰程度最高,主要干扰源为钓鱼、行人和施工,荷塘和开阔水域主要干扰为打渔船.本研究表明,对于越冬期的青头潜鸭,池塘是重要觅食地,荷塘可作为躲避干扰的休息场所,开阔水域可作为稳定的觅食栖息场所.对青头潜鸭的保护应考虑到不同栖息地的生态作用,以及青头潜鸭对不同干扰的容忍度,采取相应措施开展保护行动.     

Habitat modification by the stream macrophyte Justicia americana and its effects on biota

We conducted an in-stream experiment to determine if and by what mechanisms the emergent macrophyte, Justicia americiana, enhances streambed stability and influences associated benthic organisms. Treatments included removal of aboveground stems, removal of stems and rhizomes, and a control. Stone stability and embeddedness were higher within intact patches of Justicia compared with areas where stems and rhizomes were removed. Presence of belowground structures binding stones and higher embeddedness were responsible for differences in stone stability among treatments. Sediment deposition was highly variable among treatments; however, silt and clay deposition was highest in the control when Justicia stems reached maximum biomass. Response of neighboring benthic organisms to Justicia treatments varied with organism mobility and trophic level. Sedentary unionid mussels were more abundant in the control than in the stem and rhizome-removal treatment, whereas abundance of mobile snails (Elimia ucheensis) and sessile plants (Podostemon ceratophyllum and mosses) did not differ among treatments. Justicia appears to modify the stream environment by: (1) increasing stability of streambed sediments, and (2) reducing current velocity, thereby enhancing deposition of fine sediments and organic matter.     

Patch occupancy in the endangered butterfly Lycaena helle in a fragmented landscape: effects of habitat quality, patch size and isolation

While there is agreement that both habitat quality and habitat network characteristics (such as patch size and isolation) contribute to the occupancy of patches by any given species, the relative importance of these factors is under debate. This issue is of fundamental ecological importance, and moreover of special concern for conservation biologists aiming at preserving endangered species. Against this background we investigated patch occupancy in the violet copper Lycaena helle, one of the rarest butterfly species in Central Europe, in the Westerwald area (Rhineland-Palatinate, Western Germany). Occupied (n = 102) differed from vacant (n = 128) patches in altitude, size, connectivity, availability of wind shelter, in the abundance of the larval host-plant, in the abundance of a grass species indicating favorable habitat conditions and in the abundance of nitrophilous plants. Overall, patch occupancy was primarily determined by patch size, connectivity and the abundance of the larval host plant, while all other parameters of habitat quality were of subordinate importance. Therefore, our findings suggest that even for extremely sedentary species such as L. helle habitat networks are decisive and—next to the preservation of habitat quality—need to be an integral part of any conservation management for this species.     

Genetic structure of endangered Emmenopterys henryi Oliv. based on ISSR polymorphism and implications for its conservation

Inter-simple sequence repeat (ISSR) markers were used to determine the genetic variation and genetic differentiation of nine populations of Emmenopterys henryi Oliv., an endangered plant endemic to China. Relatively low genetic diversity was detected at population level (the percentage of polymorphic loci P=22.56%, the number of alleles per locus A=1.183+/-0.045, the effective number of alleles per locus A(E)=1.007+/-0.345, Nei's gene diversity h=0.071+/-0.017, Shannon information index I=0.104+/-0.025). However, the genetic diversity at species level was relatively high (P=56.05%; A=1.561+/-0.498, A(E)=1.325+/-0.371, h=0.191+/-0.199, I=0.287+/-0.284). Analysis of molecular variance showed that most of the ISSR variation (68.03%) in E. henryi occurred among populations. The estimated Nm from F (ST )was 0.235. It indicated that the fragmentation and isolation of populations might result from specific evolutionary history and anthropogenic activity. Consequently, genetic drift might play an important role in determining the genetic structure of E. henryi. Conservation strategies for this endangered species are proposed based on the genetic data.     

Spawning habitat enhancement in the European bullhead (Cottus gobio), an endangered freshwater fish in degraded lowland rivers

Due to river regulation, the natural habitat of the European bullhead (Cottus gobio) has been degraded and often there is an apparent lack of suitable spawning substrates (hard objects like stones). Addition of artificial structures to degraded habitats may be a very promising tool for habitat enhancement. In this study, we evaluated the use of ceramic tiles as artificial spawning substrates in canalised and (remaining) meandering parts of anthropogenically perturbated lowland rivers in Flanders (northern part of Belgium). Furthermore, we examined whether water depth and velocity were important determinants for the choice of tiles in these different river trajectories. Tiles were successfully used by the bullhead as spawning substrates. In the meandering parts of the river, the number of egg deposits was significantly positively correlated with water depth, while in canalised river parts, water depth and velocity were of no importance for tile usage. In general, supplementation of rivers with artificial substrates like tiles may be a promising, inexpensive and easy-to-use enhancement technique for degraded bullhead spawning habitat.     

New Substrates for Enteropeptidase: I. Biologically Active Hepta-, Octa-, and Nonapeptides

Enteropeptidase (enterokinase, EC 3.4.21.9) hydrolyzes peptide bonds formed by carboxyl groups of Lys or Arg residue if less than four negatively charged amino acid residues are in positions P ₂–P ₅ of its substrate. We determined the kinetic parameters of three substrates of this type: human angiotensin II (AT) (DR VYIHPF) and the Hb(2–8) (LTAEEK A) and Hb(1–9) (MLTAEEK AA) peptides of the cattle hemoglobin -chain. The K _m values for all the substrates (10^–3 M) were one order of magnitude higher than those of the typical synthetic substrates of enteropeptidase or chimeric proteins with the –DDDDK– full-size linker (K _m 10^–4 M). The k _cat values for AT and Hb(2–8) were also close and low (30 min^–1). The general hydrolysis efficiency of such substrates is no more than 1% of the corresponding value for the typical peptide and protein substrates of the enteropeptidase. However, the elongation of Hb(2–8) peptide by one amino acid residue from both its N- and C-termini results in a dramatic increase in the catalytic efficiency of the hydrolysis: the k _cat value for Hb(1–9) is 1510 min^–1, which means that it is hydrolyzed only three times less effective than the chimeric protein with the full-size linker.