Butterfly communities along an elevational gradient in the Tons valley,Western Himalayas: Implications of rapid assessment for insect conservation

As time and money is limited, explicit, cost-effective, quick, and appropriate methods are needed to assist conservation planners and managers for making quick decisions. Butterflies promise to be a good model for rapid assessment and habitat monitoring studies because they are widespread, conspicuous, and easily recognizable and they are effective indicators of forest health. We conducted a rapid assessment of butterflies at five disturbance gradient sites that varied in elevation from 900 m a.s.l. to 3500 m a.s.l. for 20 days during March–April 2010 and recorded 79 butterfly species and 1504 individuals in the Tons valley in Western Himalayas. We were able to sample approximately 77% (123 species) of the estimated species richness on continuing the sampling until July 2010. Species richness at the study site is estimated to be 159 (95% CI: 145–210) species. Diversity was highest in heterogeneous habitats and decreased towards homogeneous habitats. Unique species were highly restricted to lowest disturbed sites. Using Pearson's correlation analysis, the strongest vegetative predictors of butterfly richness were plant species richness, canopy cover, and herb and shrub density. Butterfly species richness and abundance were highly correlated with altitude, temperature, relative humidity, fire signs, and livestock abundance. We also found positive cross-taxon correlation among butterflies, moths, and beetles across sites, indicating that butterflies can be used as surrogate or indicator taxa for insect conservation. Short sampling periods providing comprehensive estimates of species richness were reliable for identifying habitats and sites with the most conservation value in the Tons valley landscape.     

Diel variation in movement patterns and habitat use by the Iberian endemic Cabrera vole: Implications for conservation and monitoring

Understanding variations in animal movement and habitat selection behaviour over fine spatial and temporal scales remains a particularly challenging goal in ecology and conservation. Here we document for the first time the diel variations in movement patterns and habitat use by wild-ranging Cabrera voles in fragmented Mediterranean farmland, based on radiotracking data (2006–2008) of 25 adult individuals occupying stable home-ranges in vegetation mosaics dominated by wet grasses and shrubs. Results indicated that the proportion of time animals spent moving, the distance moved, and the selection strength of main vegetation types were closely linked behavioural traits, which varied considerably across different periods of the 24-h cycle. In general, voles moved more frequently and over larger distances during daytime (between 06 h15–22 h00), which was when wet grasses were also used more intensively. These patterns were generally consistent across seasons, though during the dry season there was some tendency for a decrease in movement activity during the hottest hours of the day (between 10 h15–14 h00), with peaks around crepuscular hours (06 h15–10 h00 and 18 h15–22 h00). Overall, our study provides evidence that Cabrera voles may show notable shifts in habitat use and movement patterns on a finer scale than previously considered. This supports the idea that knowledge of the diel variations in species movement-habitat relationships should strongly contribute to improving local habitat management, as well as effective sampling and monitoring programs targeting the species.     

Investigating habitat-specific plant species pools under climate change

We used 474 European plant species to analyse the impacts of climate and land-use change on the composition of habitat-specific species pools in Germany. We quantified changes in the probability of occurrence of species in a grid cell using an ensemble of three statistical modelling techniques, namely generalized linear models (GLMs), generalized additive models (GAMs) and random forests (RFs), under three scenarios (average change +2.2, +2.9, and +3.8 °C up to 2080). We evaluated the impact on single species occurrence and resulting species pools considering their affiliation to ten major terrestrial habitat types in both current (1961–90) and future projections (2051–80). Current habitat-specific species pools declined in size across all scenarios, e.g. by 24 ± 13% (mean ± s.d.) under the most severe scenario. We show that species responses may strongly vary among scenarios and different habitats with a minimum average projected range loss of 14% (±18%; species typical to urban habitats under moderate climate change assumptions, average temperature increase +2.2 °C) to a maximum average projected range loss of 56% (±29%; species assemblages from mountain communities below the alpine zone at +3.8 °C). A separate analysis of species composition in habitat-specific species pools revealed a significant interaction between the scenario and the major habitat classes. We found a higher risk for habitat types with high conservation value characterised by a significant association between number of nationally endangered species and projected range loss in major habitats. Thus, habitat-specific management and application of measures favouring dispersal are required for mitigation of climate change impacts.     

How does dune morphology shape coastal EC habitats occurrence? A remote sensing approach using airborne LiDAR on the Mediterranean coast

We examined the relationship between coastal habitats (sensu European Union Habitats Directive) and local dune morphology along a Mediterranean coastal dune system by integrating field collected vegetation data and remotely sensed imagery. Specifically, we described the morphological profile of each EC habitat based on the morphological variables that are most likely to affect their occurrence, including elevation, slope, curvature, northness, eastness and sea distance. In addition, we assessed the role and strength of each morphological variable in determining the occurrence of EC habitats.We used 394 random vegetation plots representative of six EC habitats (Habitat 1210: “Annual vegetation of drift lines”; Habitat 2110: “Embryonic shifting dunes”; Habitat 2120: “Shifting dunes along the shoreline with Ammophila arenaria”; Habitat 2210 and 2230: “Crucianellion maritimae fixed beach dunes” and “Malcolmietalia dune grasslands”; Habitat 2250: “Coastal dunes with Juniperus spp.”; Habitat 2260: “Cisto-Lavanduletalia dune sclerophyllous scrubs”) found along the Tyrrhenian coast of central Italy. We derived each morphological variable from a DTM (Digital Terrain Model) obtained from 2-m resolution LiDAR (Light Detection And Range) images. The mean value of each variable was calculated at different spatial scales using buffer areas of increasing radius (2 m, 4 m, 8 m) around each vegetation plot. Mean morphological values for each EC habitat were compared using Kruskal-Wallis rank test. The role and strength of the relationship between habitat type and the morphological variables were assessed using Generalized Linear Models.EC habitats occur differentially across dune morphology, and the role and strength of each morphological variable define habitat specificity. Dune elevation and sea distance were determined to be the key factors in shaping EC habitat occurrence along this section of the Mediterranean coast. Identification of the close relationship between habitat type and morphological variables deriving from airborne LiDAR imagery points to the high potential of such remote sensing tool for analyzing and monitoring the integrity of coastal dune ecosystems. As airborne LiDAR enables the rapid collection of extremely accurate topographic data over large areas, it also offers useful information for the management of these threatened and fragile ecosystems.     

Winter foraging habitat selection of brown-eared pheasant (Crossoptilon mantchuricum) and the common pheasant (Phasianus colchicus) in Huanglong Mountains, Shaanxi Province

The foraging habitat selections of brown-eared pheasant (Crossoptilon mantchuricum) and the common pheasant (Phasianus colchicus) were studied in Huanglongshan Nature Reserve Shaanxi, China. Foraging habitat characteristics were measured on the basis of expected differences between species at 183 sites from November to December 2006 and January 2007. The results showed that both species selected foraging habitats with altitude (<1200 m), conifer forest, half sunny and half shady slope, sunny slope, density of trees (<5 individuals/100 m²), cover of shrub (>50%), visibility class (<10%) and distance to water source (<300 m). However, the brown-eared pheasant selected habitats with cover of trees (30–50%), middle or lower slope location, distance to edge of woods (<300 m) and human disturbance (<500 m), and the selection on density of shrub was not observed, compared to the selections on cover of trees (<30%), lower slope location, distance to edge of woods (<500 m) and human disturbance (<300 m), and density of shrub (>500 individuals/100 m²) for common pheasant. We also found that the common pheasant avoid predators by concealment whereas brown-eared pheasant evade predations by running away strategy.     

Wild bison as ecological indicators of the effectiveness of management practices to increase forage quality on open rangeland

Habitat manipulations through the use of fire or mechanical treatments are often used to combat woody plant encroachment and increase foraging opportunities for wildlife and livestock. This creates spatial heterogeneity in habitat quality that large herbivores should respond to in ways predicted by ideal free distribution theory. We monitored free-ranging bison to test whether, (1) manipulated habitats offer higher quality forage than habitats in undisturbed rangeland, (2) bison respond through changes in herd composition or activity to differences in habitat quality, and (3) burned and mechanically treated habitats offer similar forage qualities. We found that habitat types burned ∼10 years ago continue to produce higher quality forage as evidenced by bison fecal N concentration (14.4 g kg⁻¹ dry mass) than open (10.5 g kg⁻¹), closed (10.6 g kg⁻¹), or mechanically manipulated habitats (11.7 g kg⁻¹). Bison herd composition and activity did not vary across habitat types within seasons, despite some between-season variation in overall group composition with sexual segregation being most evident before mid-summer. For semi-arid rangelands encroached with woody vegetation (e.g. piñon–juniper in the western USA) our evidence from free-ranging bison indicates that burning results in higher quality forage than occurs in both mechanically manipulated and undisturbed habitats. Bison roam widely from water, sample available vegetation continuously, and are long-lived gregarious animals that learn to exploit the spatiotemporal heterogeneity in their large home ranges. Bison also have very similar diets to cattle and so, where bison and cattle are allowed to comingle, we suggest the foraging parameters of free-ranging bison are effective ecological indicators of rangeland quality for both bison and cattle.     

Determinants of smooth-coated otter occupancy in a rapidly urbanizing coastal landscape in Southeast Asia

Urbanization often has negative impacts on wildlife, nevertheless many species can persist in heavily modified habitats. Understanding factors that promote species persistence in urbanizing landscapes is therefore important for maintaining biodiversity in changing landscapes and may inform more biodiversity-friendly development. We investigated effects of landscape-scale variables on habitat occupancy of Smooth-coated otter (Lutrogale perspicillata) in the Inner Gulf of Thailand. In this internationally important wetland complex, 86% of natural habitats have been altered and are now highly urbanized. We conducted track and sign surveys in 60, 25 km² grid cells encompassing 1,474 km². Within each cell, we quantified the landscape cover types including urban areas, natural habitat (predominately thin ribbons of mangrove along waterways), agriculture, aquaculture, and potential prey availability using a GIS and field surveys. We used occupancy models to identify habitat variables that affected probability of detection and occupancy. Estimated otter occupancy, based on the top model, was 0.33 ± 0.07 (95% CI 0.18–0.48) and detection probability was 0.50 ± 0.05 (95% CI 0.41–0.60). Otter occupancy was positively associated with the proportion of natural habitat and the cover of traditional aquaculture ponds, but negatively associated with agriculture and urban cover. The remaining natural patches appear to act as critical refuges for otter, allowing them to persist in an otherwise heavily transformed landscape. Because aquaculture ponds are likely important prey sources for otters, it may lead to conflict with aquaculture farmers. Further studies of feeding and movement patterns in cooperation with aquaculture farmers would be beneficial for developing detailed management plans for the species in this human dominated landscape.     

Detailed study of a river corridor plant distribution pattern provides implications for river valley conservation

River valleys have been subjected to human-induced changes for centuries, but they are still considered regional hotspots of biodiversity. In central Europe, some vascular plant species demonstrate confinement to the corridors of large rivers. They are termed river corridor plants (RCPs). RCPs are an important component of regional biodiversity and include a high proportion of threatened species, thus they deserve attention. Here we examine: (1) the detailed distribution pattern of RCPs within a river valley, (2) the habitat preferences of RCP species, and (3) the correlation between the richness of RCP species and selected variables. The studied variables include: river bed proximity, distance from the river mouth, floodplain coverage, richness of native, red listed and invasive species, and number of habitats considered to be of Europaean Community importance. Surveys were conducted in 10 transects running perpendicularly to the San River bed (Poland, central Europe). Each transect was divided into 14 plots (1 km × 1 km). In each plot, the site locations of RCPs as well as their habitats were recorded. The occurrence of all vascular plant species in a particular plot was also noted. The richness and abundance of RCP species depended on the distance from the river and the floodplain coverage in a plot. The plots located in the vicinity of the river were the richest in RCP species and usually harbored the largest number of native, red-listed and invasive species. They were also characterized by the largest number of habitats considered to be of importance to the European Community. RCP species differed in the degree of confinement to habitats regarded as typical for them. Some of the RCP species were recorded only within typical habitats while others were found in several different types of habitats, including anthropogenic ones. Knowledge concerning the RCP distribution pattern and its correlates can make restoration initiatives in river valleys more effective. While implementing conservation measures in river valleys, one should keep in mind that: (1) hotspots of RCP and invasive species spatially overlap and (2) anthropogenic linear elements occurring within river valleys constitute important habitats for some RCP species.     

The extent of edge effects in fragmented landscapes: Insights from satellite measurements of tree cover

Due to deforestation, intact tropical forest areas are increasingly transformed into a mixture of remaining forest patches and human modified areas. These forest fragments suffer from edge effects, which cause changes in ecological and ecosystem processes, undermining habitat quality and the offer of ecosystem services. Even though detailed and long term studies were developed on the topic of edge effects at local scale, understanding edge effect characteristics in fragmented forests on larger scales and finding indicators for its impact is crucial for predicting habitat loss and developing management options. Here we evaluate the spatial and temporal dimensions of edge effects in large areas using remote sensing. First we executed a neighborhood pixel analysis in 11 LANDSAT Tree Cover (LTC) scenes (180 × 185 km each, 8 in the tropics and 3 in temperate forested areas) using tree cover as an indicator of habitat quality and in relation to edge distance. Second, we executed a temporal analysis of LTC in a smaller area in the Brazilian Amazon forest where one larger forest fragment (25,890 ha) became completely fragmented in 5 years. Our results show that for all 11 scenes pixel neighborhood variation of LTC is much higher in the vicinity of forest edges, becoming lower towards the forest interior. This analysis suggests a maximum distance for edge effects and can indicate the location of unaffected core areas. However, LTC patterns in relation to fragment edge distance vary according to the analyzed region, and maximum edge distance may differ according to local conditions. Our temporal analysis illustrates the change in tree cover patterns after 5 years of fragmentation, becoming on average lower close to the edge (between 50 and 100 m). Although it is still unclear which are the main causes of LTC edge variability within and between regions, LANDSAT Tree Cover could be used as an accessible and efficient discriminator of edge and interior forest habitats in fragmented landscapes, and become invaluable for deriving qualitative spatial and temporal information of ecological and ecosystem processes.     

Improving national habitat specific biodiversity indicators using relative habitat use for common birds

It has recently been stated that the global goal of halting the loss of biodiversity by 2010 has not been met highlighting the urgent need to monitor trends in biodiversity. Our study suggests that existing indicators of bird biodiversity in Denmark are inaccurate and we present a new objective method for accurately assessing trends in specific habitats using common bird species. Bird species were selected for creating habitat specific indicators by calculating their relative habitat use (RHU) in nine different habitat categories. RHU indicates the degree to which a habitat is preferred (RHU > 2) or avoided (RHU < 0.5) by a species, relative to other habitats. Indicator sets were constructed for each habitat type using species with an RHU > 2 and revealed that existing habitat indicators, based on species lists from the Pan-European Common Bird Monitoring Scheme (PECBMS), often included species that did not in fact have preferences for those particular habitats in Denmark. Habitat specific indicators based on the new species selection method showed significant negative trends in three of nine habitat categories: coniferous forest, bog/marsh and heath. Habitat classes were further combined to create overall indicators for forest, farmland and freshwater. A comparison of these indicators with the existing indicators revealed a negative overall trend for forest habitat, which had previously been overlooked, suggesting that species selection is crucial for the development of informative indicators. The habitat specific farmland indicator confirmed the negative trend in the current farmland indicator. The methodology for indicator species selection presented here could potentially be applied for use in a global context for a wider range of taxonomic groups.     

Vertical habitat segregation as a mechanism for coexistence in sympatric rodents

Coexistence has been widely studied in small mammals and frequently is assumed to be facilitated by habitat segregation. Using live trapping and spool-and-line experiments, we analyzed habitat selection and segregation across multiples scales for Peromyscus leucopus and Ochrotomys nuttalli. At the habitat scale of a forest stand (∼1–100s ha) P. leucopus co-occurred at all sites where O. nuttalli was found, and we did not detect evidence of positive or negative associations or habitat segregation. However, O. nuttalli was restricted to early successional forests, and P. leucopus had significantly lower abundances in early successional forests than in other habitats. We found similar patterns at the mesohabitat scale of the study site (400 m²). O. nuttalli abundance increased with increasing shrub and tree densities, while increases in P. leucopus abundance were associated with open understories. At the microhabitat scale of the individual movement trail, we found vertical segregation. Movement trails for O. nuttalli were at significantly higher elevation (mean height = 142.93 ± 37.10 cm) than P. leucopus trails (mean height = 15.4 ± 4.98 cm; F-value = 35.29, p < 0.001). We concluded that microhabitat segregation was driven by differential use of vertical space for movement and foraging. We suggest O. nuttalli is superior to P. leucopus in its ability to acquire food especially in shrubby subcanopies where few acorns are available. However, P. leucopus is superior in its ability to forage and avoid predators.     

How far can a tortoise walk in open habitat before overheating? Implications for conservation

Terrestrial chelonians are threatened worldwide by habitat destruction and illegal harvesting. Tortoises are slow moving animals susceptible to dehydration and overheating during movements in open habitats. Many species inhabit arid steppes where the availability of thermally buffered refuges (e.g. burrows) is a limiting factor. Determining the maximal distance between refuges that individuals can safely traverse during the active season is thus essential. We examined the relationship between body temperature variations and movement patterns in adult Testudo graeca in the arid steppes of Morocco. Using physical and mathematical models, our results suggest that during the active season adults cannot travel more than 1 km without serious risk of overheating. However, radio-tracking suggests that free-ranging individuals are behaviourally limited to 0.5 km trips between refuges. Overall, maintaining a distance less than 0.5 km between refuges (e.g. through bush planting) is essential to limit fragmentation and to retain healthy populations. This restoration would also benefit to many other species that depend on bush-refuges.     

Ecological gradients and environmental impact in the forest dwelling Haplothrips subtilissimus (Thysanoptera: Phlaeothripidae) phenotypic variability

Classification of phenotypic variability in forest dwelling arthropods, especially in applied bioindication, remains difficult due to the complex and synergic ecological interactions. Ecologically, it corresponds with the concept of alternative ontogenies in order to maintain high population fitness. The research on the geobiont Haplothrips subtilissimus (Thysanoptera: Phlaeothripidae) morphometric plasticity alongside selected ecological gradients (temperature, humidity, food availability) and the environmental impact in the xerothermous hilly oak wood (Martinský les, SW Slovakia), have revealed that (MAN(C)OVA and Kruskal–Wallis test) the head width (p < 0.001) and anterior pronotum width (p ≤ 0.002) as the only statistically significant variables. The Kruskal–Wallis test (non parametric ANOVA) revealed significant variation (more noticeable in males) in ecologically more diverse ecotone stands. A significant correlation (p < 0.001) could be shown between the morphometric parameter pairs “head width” and “anterior pronotum width” for both sexes (0.729 for females and 0.822 for males) and between anterior and posterior pronotum width only for males (0.859). Pillai's statistics revealed an interaction of soil humidity and soil temperature which confirms female body parameters depend on habitat conditions (p = 0.011). Females responded mainly to soil temperature (p = 0.018) and food availability (p = 0.030). Soil humidity interacts with the male's morphology (soil humidity p = 0.040), while the relationship to food availability (Acarina) was not statistically significant (p = 0.350). No body parameter has been significantly affected by environmental stress.     

Plant functional traits and community assembly along interacting gradients of productivity and fragmentation

Quantifying the association of plant functional traits to environmental gradients is a promising approach for understanding and projecting community responses to land use and climatic changes. Although habitat fragmentation and climate are expected to affect plant communities interactively, there is a lack of empirical studies addressing trait associations to fragmentation in different climatic regimes.In this study, we analyse data on the key functional traits: specific leaf area (SLA), plant height, seed mass and seed number. First, we assess the evidence for the community assembly mechanisms habitat filtering and competition at different spatial scales, using several null-models and a comprehensive set of community-level trait convergence and divergence indices. Second, we analyse the association of community-mean traits with patch area and connectivity along a south–north productivity gradient.We found clear evidence for trait convergence due to habitat filtering. In contrast, the evidence for trait divergence due to competition fundamentally depended on the null-model used. When the null-model controlled for habitat filtering, there was only evidence for trait divergence at the smallest sampling scale (0.25 m × 0.25 m). All traits varied significantly along the S–N productivity gradient. While plant height and SLA were consistently associated with fragmentation, the association of seed mass and seed number with fragmentation changed along the S–N gradient.Our findings indicate trait convergence due to drought stress in the arid sites and due to higher productivity in the mesic sites. The association of plant traits to fragmentation is likely driven by increased colonization ability in small and/or isolated patches (plant height, seed number) or increased persistence ability in isolated patches (seed mass).Our study provides the first empirical test of trait associations with fragmentation along a productivity gradient. We conclude that it is crucial to study the interactive effects of different ecological drivers on plant functional traits.     

Fine-scale distribution of treeline trees and the nurse plant facilitation on the eastern Tibetan Plateau

Above-average climate warming occurred during the 20th century in high altitude regions, and alpine treelines are believed to be an early indicator to respond to these warming-related changes. However, empirical investigations on treeline dynamics showed diverse results. The main objectives of this study are: (1) to investigate if treeline position shifted and if tree recruitment changed along with climate warming, and (2) to test if adult trees have “nursing effect” on tree establishment at treelines. We investigated two Balfour spruce (Picea balfouriana Rehd. et Wils.) treelines in Chang Niang (CNT) and Dang Dui (DDT), Dingqing county, Changdu prefecture, eastern Tibet. At each treeline site, three replicate plots with a size 30 m × 50 m were established. The coordinates of each tree within the plots were recorded and the age of each tree was identified by dendrochronological method. The changes in treeline position and tree recruitment were examined from spatially fine-scale distribution of trees and their age structure. The spatial patterns of individual trees were analyzed to infer the neighborhood effects. Results indicate that plots CNT2, CNT3, DDT1 and DDT2 showed stable treeline position during the last century, whereas plots CNT1 and DDT3 showed treeline advancing movement. Tree recruitments in all the six plots were enhanced during the 20th century, with two peaks occurring in the 1890–1910s and the 1950–1990s. Seedlings and saplings showed a general clustered distribution in all the six plots. The diverse pattern of treeline movement and episodic regeneration suggest that the treeline activity is not merely a result of climate change. “Nursing effects” from adult trees may play an important role in shaping the treeline activities on the eastern Tibetan Plateau. Our findings reveal diverse patterns in treeline dynamics at a local scale and highlight the importance of incorporating biotic interactions into species distribution modeling approaches.     

Puma spatial ecology in open habitats with aggregate prey

Solitary felids are commonly associated with structurally complex habitats, where their foraging success is attributed to stealth and remaining undetected by competitive scavengers. Research in North America suggests that pumas (Puma concolor), a wide-ranging species found throughout the Americas, conform to the general characteristics of solitary felids and avoid open grasslands with aggregating prey. Researchers hypothesize that pumas are limited to structurally complex habitats in North America because of pressures from other large, terrestrial competitors. We explored the spatial ecology of pumas in open habitat with aggregating prey in Chilean Patagonia, where pumas lack large, terrestrial competitors. We tracked 11 pumas over 30 months (intensive location data for 9 pumas with GPS collars for 9.33 ± 5.66 months each) in an area where mixed steppe grasslands composed 53% of the study area and carried 98% of available prey biomass, to track resource use relative to availability, assess daily movements, quantify home ranges and calculate their density. As determined by location data and kill sites, Patagonia pumas were primarily associated with open habitats with high prey biomass, but at finer scales, preferentially selected for habitat with complex structure. On average, pumas traveled 13.42 ± 2.50 km per day. Estimated 95% fixed kernel home ranges averaged 98 ± 31.8 km² for females and 211 ± 138.8 km² for males, with high spatial overlap within and between the sexes. In a multivariate analysis, available prey biomass was the strongest predictor of variation in the size of an individual puma's home range. Finally, we determined a total puma density of 3.44 pumas/100 km², a significantly smaller estimate than previously reported for Patagonia, but similar to densities reported for North America.     

Influence of hydrology process on wetland landscape pattern: A case study in the Yellow River Delta

A comprehensive study using ecological engineering analysis was conducted on the influence of the hydrology process in the Yellow River Delta. It was found that water and sediment played an important role in the formation and maintenance of the estuarine wetland. Based on hydrological data (1950–2005), meteorological data (1954–2005) and landscape data produced from integrated Landsat TM images of the Yellow River Delta, the relationship among all the above factors has been analyzed. The results indicated that runoff, sediment discharge and the area of the reed marsh wetland, meadow wetland and tidal wetland had evidently decreased from 1986 to 2001. The runoff and sediment discharge into the Yellow River Delta at a rate of 200–300 × 10⁸ m³ and at 5–8 × 10⁸ t, respectively, were probably the most optimal range for maintaining the stable wetland landscape pattern. Regression analysis and principal component analysis showed that there was a strong positive correlation between the area of wetland landscape and runoff, sediment discharge, whereas there was a negative correlation between the area and the temperature, and there was no significant trend with precipitation levels. The water and sediment discharge are the dominant variable factors of the wetland. Human activities also have an important influence on transformation of wetland types as well as wetland degradation. Therefore, with economic development, climate change and sustainable utilization of resources, great attention should be paid to the changes of natural landscape and their causes.     

Movement of two grassland butterflies in the same habitat network: the role of adult resources and size of the study area

Abstract. 1.  Movement patterns of two butterfly species (meadow brown Maniola jurtina L. and scarce copper Lycaenae virgaureae L.) were studied in a 172 ha area within a landscape with a high percentage of suitable habitats for mark–release–recapture experiments.
2.  Adult resource density, but not patch size or larval food plant abundance, influenced the numbers and the fractions of residents, emigrants, and immigrants.
3.  Differences between species were observed in movement frequency and maximum distances moved but not in mean distances moved.
4.  The scarce copper showed much greater movement ability than expected from the results of published studies. This is believed to be a result of the comparatively large size of the study area and the high cover of suitable habitat (>50%).
5.  The mean and maximum distances travelled by butterflies reflected differences in the size of the study area.     

Hypoxia and hypercarbia in endophagous insects: Larval position in the plant gas exchange network is key

Gas composition is an important component of any micro-environment. Insects, as the vast majority of living organisms, depend on O₂ and CO₂ concentrations in the air they breathe. Low O₂ (hypoxia), and high CO₂ (hypercarbia) levels can have a dramatic effect. For phytophagous insects that live within plant tissues (endophagous lifestyle), gas is exchanged between ambient air and the atmosphere within the insect habitat. The insect larva contributes to the modification of this environment by expiring CO₂. Yet, knowledge on the gas exchange network in endophagous insects remains sparse. Our study identified mechanisms that modulate gas composition in the habitat of endophagous insects. Our aim was to show that the mere position of the insect larva within plant tissues could be used as a proxy for estimating risk of occurrence of hypoxia and hypercarbia, despite the widely diverse life history traits of these organisms. We developed a conceptual framework for a gas diffusion network determining gas composition in endophagous insect habitats. We applied this framework to mines, galls and insect tunnels (borers) by integrating the numerous obstacles along O₂ and CO₂ pathways. The nature and the direction of gas transfers depended on the physical structure of the insect habitat, the photosynthesis activity as well as stomatal behavior in plant tissues. We identified the insect larva position within the gas diffusion network as a predictor of risk exposure to hypoxia and hypercarbia. We ranked endophagous insect habitats in terms of risk of exposure to hypoxia and/or hypercarbia, from the more to the less risky as cambium mines > borer tunnels ≫ galls > bark mines > mines in aquatic plants > upper and lower surface mines. Furthermore, we showed that the photosynthetically active tissues likely assimilate larval CO₂ produced. In addition, temperature of the microhabitat and atmospheric CO₂ alter gas composition in the insect habitat. We predict that (i) hypoxia indirectly favors the evolution of cold-tolerant gallers, which do not perform well at high temperatures, and (ii) normoxia (ambient O₂ level) in mines allows miners to develop at high temperatures. Little is known, however, about physiological and morphological adaptations to hypoxia and hypercarbia in endophagous insects. Endophagy strongly constrains the diffusion processes with cascading consequences on the evolutionary ecology of endophagous insects.     

Body temperatures of Tropidurus torquatus (Squamata,Tropiduridae) from coastal populations: Do body temperatures vary along their geographic range?

We studied the geographic variation in body temperatures of the lizard Tropidurus torquatus in 10 restinga populations along approximately 1500 km of Brazilian coast. The mean activity body temperatures (30.8–36.2 °C) seems to remain constant along the populations and the differences recorded among them result from the adjustment of each lizard population to the local thermal environment (i.e. may express in part the local microhabitat temperatures occurring in each of the localities in that particular moment). Forested and open habitat tropidurine species have different mean activity body temperatures, probably as a consequence of the different thermal environments in these habitats.