Assess Habitat Quality Research Articles

Effects of nest site selection and nest concealment on nest survival of Gosling's Bunting (Emberiza goslingi)

Selecting nest sites that provide access to resources and reduce predation risk is crucial to maximizing fitness in breeding birds. Therefore, understanding what habitat features influence nest site selection and nest success is a key component of avian conservation because it allows for identification and protection of habitat that will promote population growth. We examined drivers of nest success in Gosling's Bunting (Emberiza goslingi) by evaluating variables that influence nest site choice and nest survival at 23 nests and an equal number of random, paired, non-nesting locations in a tropical savannah landscape in north-central Nigeria. Gosling's Buntings exhibited a nonrandom nest-placement pattern. Nests were either on or in proximity to large rock surfaces with nesting probability increasing when the immediate nesting area (100 m radius around the nest) consisted of 30–60% bare rock. Compared to random non-nesting sites, buntings selected areas that were low in litter cover and/or had short grass height. Daily nest survival probability was high (0.96) and was positively associated with the proportion of bare rock around the nest but negatively with the amount of litter cover. Although hatching success was 56.9%, only 30% of all nesting attempts successfully fledged a chick suggesting that nest failure occurred mostly at advanced stages of nesting (nestling phase) when renesting is less likely. Nest survival was higher at low concealment, but only significantly higher than nest failure within a restricted concealment range of 45–54%. Our findings show that microhabitat features could benefit reproduction and daily nest survival. Furthermore, by linking nest-site attributes with fitness indices, we highlight the potential importance of fitness measures as a key component of habitat quality assessment for these buntings in tropical savannahs.

Quantifying uncertainty of shipping source levels for marine soundscape modeling

Soundscape modeling is increasingly being used in assessments of marine habitat quality and to inform marine spatial planning. In most locations of interest, noise from shipping traffic and other marine vessels is the dominant anthropogenic contributor to the underwater soundscape. The noise contributions of marine vessels are typically calculated using tracking data from sources such as the automated identification system (AIS) and the vessel monitoring system (VMS). However, source levels of individual vessels in these datasets are often highly uncertain and must be estimated from incomplete information using data-driven models. Such models may be used to reliably predict mean source levels for large aggregations of vessels, but comparisons with real datasets show substantial statistical variability about the mean. Recent work, carried out using a large database of vessel noise measurements from the Enhancing Cetacean Habitat and Observation (ECHO) Program, has been used to develop statistical models that predict source levels based on ship type, design characteristics, and operating conditions. These models include a predictive component, based on observed trends, as well as a random component based on the residual variability of the data. This random component can be used to quantify the uncertainty of vessel noise emissions for soundscape modeling.

The location and vegetation physiognomy of ecological infrastructures determine bat activity in Mediterranean floodplain landscapes

Ecological infrastructures (EI), defined as natural or semi-natural structural elements, are important to support biodiversity and could play a crucial role in counteracting the well-known impacts of intensive agriculture. Yet, the importance of EI remains largely unexplored in Mediterranean agricultural landscapes and for species providing essential ecosystem services such as bats. Here, we evaluated the role of different EI types – in terms of location (riparian vs terrestrial) and vegetation physiognomy (woody vs non-woody) – in shaping bat guild activity in crop fields located in the floodplains of the Iberian Peninsula. We recorded 60,732 bat sequences in 96 crop fields and characterised 106 EI patches via an adaptation of the Biodiversity Potential Index (BPI). We found that the activity of mid-range echolocators (MRE) and long-range echolocators (LRE) was twofold higher when the nearest EI patch was riparian (i.e., contiguous to a watercourse) than when it was terrestrial. When assessing changes in bat activity in crop fields in relation to a gradient distance from EI types, our results revealed both distinct and similar effects of the location and vegetation physiognomy of the EI on bat guilds. For instance, while only the LRE guild positively responded to the proximity of woody EI, both MRE and LRE showed a marked increase of activity when increasing distances to non-woody EI, thus suggesting low bat activity levels near these features. Our habitat quality assessment also revealed that woody EI and riparian EI had higher biodiversity potential and related habitat quality, thus contributing to our understanding of bat responses to EI type in crop fields. As riparian areas are rarely targeted in biodiversity-friendly measures in farmland, we strongly recommend including riparian EI (especially the woody type) in conservation planning as they are crucial for both biodiversity conservation and ecosystem functioning.

A Case Study Evaluating Water Quality and Reach-, Buffer-, and Watershed-Scale Explanatory Variables of an Urban Coastal Watershed

Land use land cover within a watershed influences stream water quality, habitat quality, and biological community structure. As development and associated impervious surface increases in a watershed, changes in storm water and nutrient inputs generally cause declines in habitat conditions and biodiversity. The first goal of our study was to evaluate the water quality in the Charles River watershed, in which our objective (G1O1) was to establish ten 100-meter reach-scale sampling stations and conduct physical, chemical, and biological assessments. The second goal of this study was to better understand the direct and indirect effects of hierarchical variables on water quality in the Charles River watershed. Our first objective of our second goal (G2O1) was to calculate land use land cover percentages at the pour-point subwatershed and local 100-meter buffer scale for each of our ten 100-meter reach sampling stations. Our second objective of our second goal (G2O2) was to use path analysis to determine the direct and indirect effects of land use land cover and impervious surface on water quality in the Charles River watershed. The results of G1O1 were that habitat quality assessments ranged from “marginal” to “optimal” and biological quality assessments ranged from “fair” to “good“, indicating overall “fair” or better water quality conditions in the watershed. The results of G2O2 were that our path analysis resulted in differences in effects of development between the buffer and sub-watershed scale. At the buffer scale, water quality was influenced more negatively by the percentage of developed land area versus the percentage of impervious cover. While both buffer development and habitat quality had a direct effect on Streamside Biosurvey Macroinvertebrates, buffer development also directly hindered habitat quality, thus having an indirect effect on Streamside Biosurvey Macroinvertebrates through habitat. Streamside Biosurvey Macroinvertebrate scores were shown to be more sensitive to development within the buffer versus at the sub-watershed scale, where impervious cover was a more important indicator of stream water quality. Through this small case study of 10 stations within the Charles River watershed, we illustrated how citizen-science level water quality assessments can be combined with water chemistry and hierarchical LULC data to provide insights into potential direct and indirect effects on water quality. As the fields of landscape ecology and conservation continue to grow, so does our ability to determine changes in land development and devise management strategies aimed at improving water quality.

A Comparative Evaluation of Hydromorphological Assessment Methods Applied in Rivers of Greece

The ecological assessment of all surface water bodies in Europe according to the Water Framework Directive involves the monitoring of biological, physicochemical and hydromorphological quality elements. For the hydromorphological assessment in particular, there are numerous methods that have been developed and adopted by EU member countries. With this study, we compared three different methods (River Habitat Survey, Morphological Quality Index and River Hydromorphology Assessment Technique) applied in 122 river reaches that are part of the National Monitoring Network of Greece. The main objectives were (a) to identify whether different assessment systems provide similar classifications of hydromorphological status and (b) to distinguish strengths and weaknesses associated with the implementation of each method. Our results show that the River Hydromorphology Assessment Technique (RHAT) and the Morphological Quality Index (MQI) resulted in the same classification for 58% of the studied reaches, while 34% of the remaining cases differed by only one quality class. Correlations between the two indices per river type (ICT) showed that the two indices were strongly correlated for water courses located at low altitudes. Concerning the HMS index of the River Habitat Survey (RHS), which is an index that reflects the overall hydromorphological pressure, it showed larger differences with the other two indices, mainly because it classified more sites as “Poor” and “Bad” quality classes. Based on our results, we recommend that the two indices, RHAT and MQI, can be implemented complementary to the RHS for providing a rather easy and quick assessment of the overall hydromorphological status, at least until a national hydromorphological database is compiled that will allow for the proper adaptation of the Habitat Quality Assessment (HQA) index.

Ecological habitat quality assessment of a tropical estuary using macrobenthic functional characteristics and biotic indices

Ecological habitat quality assessment of a tropical estuary using macrobenthic functional characteristics and biotic indices

Habitat quality assessment of Alpine Streams using ARISE: a classification tool for Alpine RIver and Stream Ecosystems in Khunjerab National Park Gilgit, Pakistan

This study is based on detailed multidisciplinary field investigations with the use of the Alpine River and Stream Ecosystems (ARISE) Classification to assess spatial and temporal patterns of benthic macroinvertebrate communities in relation to altitudinal and channel stability gradients. We expected the field validation through the use of an innovative ARISE classification approach of alpine aquatic ecosystems by collecting physicochemical variables and benthic macroinvertebrate community data from various stream locations of Khunjerab National Park (Pakistan). The significant differences in physicochemical habitat structure and altitudinal changes of benthic macroinvertebrate communities (i.e., richness, abundance, and diversity) were observed among the ARISE classification categories. For instance, the early spring categories had high Shannon-Wiener index (1.377) than summer (1.267), while summer season categories had high turbidity (>5NTU). Early spring mercury nival (0.00083 mg/L) and aluminum nivo-kernal (0.25 mg/L) were also found above permissible levels according to the World Health Organization (WHO). The multivariate statistical techniques showed a strong correlation among physicochemical and biological parameters of stream classification categories suggesting the increased applicability of the use of the ARISE classification approach. This study is expected to contribute to the advancement in the method of the stream monitoring program and improve conservation and management of the alpine benthic macroinvertebrate diversity further in Pakistan, the Asian Himalayas, and beyond. HIGHLIGHTS The ARISE categories of alpine streams were evaluated using physicochemical and biological indicators in Khunjerab National Park, Pakistan. The distinctive ARISE classification reflects community composition and structure (density, diversity, evenness, and richness) and additionally biotic and diversity indices. Baseline information is presented to understand the current features for the conservation and management of alpine lotic ecosystems.

Linking MSPA and Circuit Theory to Identify the Spatial Range of Ecological Networks and Its Priority Areas for Conservation and Restoration in Urban Agglomeration

Rapid urbanization has led to the continuous degradation of natural ecological space within large urban agglomerations, triggering landscape fragmentation and habitat loss, which poses a great threat to regional ecological sustainability. Ecological networks (ENs) are a comprehensive control scheme to protect regional ecological sustainability. However, in the current research about ENs, most studies can only determine the orientation of ecological corridors but not their specific spatial range. This leads to the fact that ENs can only be abstract concepts composed of points and lines, and cannot be implemented into concrete spatial planning. In this study, taking the Shandong Peninsula urban agglomeration as an example, ecological sources were identified by morphological spatial pattern analysis (MSPA) and habitat quality assessment, ecological resistance surfaces were constructed based on habitat risk assessment (HRA). And circuit theory was used to simulate the ecosystem processes in heterogeneous landscapes via by calculating the cumulative current value and cumulative current recovery value, to identify the spatial range and key areas of ecological corridors. The results showed that the ENs includes 6,263.73 km2 of ecological sources, 12,136.61 km2 of ecological corridors, 283.61 km2 of pinch points and 347.51 km2 of barriers. Specifically, ecological sources were distributed in a spatial pattern of five groups, and ecological corridors were short and dense within groups, long in distance and narrow in width between groups. The pinch points and barriers mainly exist in the ecological corridors connecting the inner and outer parts of the central city and in the inter-group corridors. In order to ensure the connectivity and effectiveness of ENs, it is necessary to focus on the pinch points and barriers and include them in the priority areas for protection and restoration. Based on MSPA and circuit theory, this study provides a new method for determining the spatial range of ENs and the specific locations of priority areas, and provides a feasible solution for the concrete implementation of ENs to achieve effective ecological protection and restoration.

Assessment of river basin habitat quality and its relationship with disturbance factors: A case study of the Tarim River Basin in Northwest China

Assessment of river basin habitat quality and its relationship with disturbance factors: A case study of the Tarim River Basin in Northwest China

Estimating the population size and habitat quality of the Endangered fish Tlaloc hildebrandi in Mexico

The Chiapas killifish Tlaloc hildebrandi is an Endangered and endemic fish that inhabits wetlands, mountain streams, and rivers in Chiapas, Mexico. This species is considered vulnerable due to accelerated human population growth in its distribution range and the species’ low genetic diversity. To evaluate the conservation status of the species, we assessed habitat quality and estimated the population size of the remnant populations in the Amarillo River subbasin using the capture-mark-recapture technique. Our results showed substantial levels of habitat perturbation in the Amarillo River subbasin, including water pollution with a high presence of coliforms, the presence of exotic species, and modified habitat quality, which has resulted in a decrease in population sizes and the extirpation of certain populations. Our estimates of the population sizes of T. hildebrandi based on the Jolly-Seber model showed dramatically low population sizes, ranging from 93 to 208 fish across sites. Gross population sizes varied temporally, and the location of these populations in isolated sites may increase demographic stochasticity. To preserve some of these populations, urgent conservation and management activities must be implemented. We suggest the establishment of conservation areas for the species in the Fogótico River (which has the best water quality and habitat conditions) and habitat restoration in the protected areas of La Kisst and María Eugenia Mountain Wetlands, where populations of T. hildebrandi could be reintroduced. Finally, we propose the implementation of ex situ conservation programs to maintain genetic diversity and prevent local extinctions of the most vulnerable populations.

Bioacoustically derived migration arrival times in boreal birds: implications for assessing habitat quality

Long-distance migrant songbirds are declining globally. Reversing declines requires a good understanding of habitat quality. Local studies have shown that territory settlement date (arrival) is generally correlated with density and productivity. Despite widespread acceptance, large-scale multispecies demonstrations of arrival time being correlated with habitat quality are lacking. We investigated whether arrival date estimated from ecozonal scale bioacoustic monitoring could be predicted by an independent estimate of estimated density for Ovenbird (<em>Seiurus aurocapilla</em>), Tennessee Warbler (<em>Leiothlypis peregrina</em>), and Yellow-rumped Warbler (<em>Setophaga coronata</em>). We also examined local Ovenbird settlement patterns by comparing relative arrival and observed local density differences between nearby territories. Arrival date was estimated as the first focal species detection date on a breeding territory and the cure4insect R package was used to predict estimated average density. Using predicted average density as a habitat quality proxy, we found earlier arrivals in higher quality territories (Ovenbird 1.04 +/- 0.33 days earlier, Tennessee Warbler 1.96 +/- 0.36 days earlier, Yellow-rumped Warbler 1.23 +/- 0.54 days earlier). We also showed that arrival time was earlier in habitats preferred by each species. Spatial patterns of arrival varied among species although latitude was always an important predictor. Locations where predicted Ovenbird densities were estimated to be higher were filled before sites with lower predicted density but only 600 m away (2.9 +/- 1.4 days earlier). Correlating migrant arrival time and density suggests density is a reasonable measure of habitat quality. Combined, density and arrival data from bioacoustics provide a low-cost habitat-assessment tool that better informs the types of forest that need to be protected for species of concern, which will be particularly important as land-use and climate change impacts increase in the boreal forest.

Biodiversity and Habitat Quality Assessment of Unlined Lower Ganga Canal

Biodiversity and Habitat Quality Assessment of Unlined Lower Ganga Canal

Fusing Sentinel-1 and -2 to Model GEDI-Derived Vegetation Structure Characteristics in GEE for the Paraguayan Chaco

Vegetation structure is a key component in assessing habitat quality for wildlife and carbon storage capacity of forests. Studies conducted at global scale demonstrate the increasing pressure of the agricultural frontier on tropical forest, endangering their continuity and biodiversity within. The Paraguayan Chaco has been identified as one of the regions with the highest rate of deforestation in South America. Uninterrupted deforestation activities over the last 30 years have resulted in the loss of 27% of its original cover. The present study focuses on the assessment of vegetation structure characteristics for the complete Paraguayan Chaco by fusing Sentinel-1, -2 and novel spaceborne Light Detection and Ranging (LiDAR) samples from the Global Ecosystem Dynamics Investigation (GEDI). The large study area (240,000 km2) calls for a workflow in the cloud computing environment of Google Earth Engine (GEE) which efficiently processes the multi-temporal and multi-sensor data sets for extrapolation in a tile-based random forest (RF) regression model. GEDI-derived attributes of vegetation structure are available since December 2019, opening novel research perspectives to assess vegetation structure composition in remote areas and at large-scale. Therefore, the combination of global mapping missions, such as Landsat and Sentinel, are predestined to be combined with GEDI data, in order to identify priority areas for nature conservation. Nevertheless, a comprehensive assessment of the vegetation structure of the Paraguayan Chaco has not been conducted yet. For that reason, the present methodology was developed to generate the first high-resolution maps (10 m) of canopy height, total canopy cover, Plant-Area-Index and Foliage-Height-Diversity-Index. The complex ecosystems of the Paraguayan Chaco ranging from arid to humid climates can be described by canopy height values from 1.8 to 17.6 m and canopy covers from sparse to dense (total canopy cover: 0 to 78.1%). Model accuracy according to median R2 amounts to 64.0% for canopy height, 61.4% for total canopy cover, 50.6% for Plant-Area-Index and 48.0% for Foliage-Height-Diversity-Index. The generated maps of vegetation structure should promote environmental-sound land use and conservation strategies in the Paraguayan Chaco, to meet the challenges of expanding agricultural fields and increasing demand of cattle ranching products, which are dominant drivers of tropical forest loss.

Impact of urbanization on the food–water–land–ecosystem nexus: A study of Shenzhen, China

The food–water–land–ecosystem (FWLE) nexus is fundamental for achieving sustainable development. This study examines the influence of urbanization on the FWLE nexus. Toward this end, land was deemed as an entry point. Therefore, the impact of urbanization on the nexus was explored based on changes in land use. We selected Shenzhen, a city in China, as the study area. First, a land change modeler was employed to analyze historical land-use changes from 2000 to 2010, to build transition potential submodels, and to project future land-use patterns for 2030 under a business-as-usual scenario. Second, based on land-use maps, we assessed habitat quality, water yield, and water supply from 2000 to 2030 using Integrated Valuation of Ecosystem Services and Tradeoffs. Moreover, crop production was estimated according to statistical materials. Finally, the study presents the analyses and discussion of the impacts of urbanization on ecosystem services related to the FWLE nexus. The results of land-use changes indicated that a significant expansion of artificial surfaces occurred in Shenzhen with varying degrees of decrease in cultivated land, forest, and grassland. Furthermore, habitat quality, water supply, and crop production decreased evidently due to rapid urbanization. In contrast, the total water yield indicated an upward trend owing to the increased water yield from increasing artificial surfaces, whereas water yield from other land-use areas declined, such as the forest and grassland. The results demonstrated a significant positive correlation between artificial surfaces and total water yield. However, negative correlations were observed in the interaction among habitat quality, water supply, and crop production. The study presented temporal and spatial assessments to provide an effective and convenient means of exploring the interactions and tradeoffs within the FWLE nexus, which, thus, contributed to the sustainable transformation of urbanization.

The ecological niche and conservation value of Central European grassland orthopterans: A quantitative approach

The ongoing biodiversity decline across taxonomic groups, including insects, is tightly related to land-use changes and habitat degradation. To assess habitat quality, proper bioindicators that allow efficient monitoring of temporal changes in habitat properties and help to understand the role of anthropogenic activities in shaping habitat characteristics, are needed. Orthopterans have been previously proposed as promising bioindicators for grassland ecosystems; however, comprehensive quantitative information on their habitat preferences is lacking, which hinders full utilization of their bioindication potential. In this study, we surveyed orthopteran assemblages and quantified local environmental conditions at 476 grassland sites in Central Europe. To model orthopteran habitat preferences, the Maxent approach was employed, which allowed us to detect continuous species responses to particular habitat characteristics (moisture, vegetation cover, vegetation height, average seasonal temperature, and direct radiation). We calculated ecological niche indices describing niche widths, species optima, and the relative importance of particular environmental variables for a total of 38 analysed species. Evaluation of final Maxent models showed that their predictive power was high for the great majority of investigated species. Red-listed species had significantly narrower niches compared to unlisted orthopterans. In addition, application of the developed quantitative ecological niche indices for ecological and conservation studies was demonstrated on an independent, previously published dataset. The development of quantitative ecological niche indices coupled with the existing time- and cost-effective survey methods, also allowing adoption of citizen science approaches, makes orthopterans an optimal model insect group for assessment of grassland condition and conservation.

Using historical dip net data to infer absence of flatwoods salamanders in stochastic environments.

Local extinction and undetected presence are two very different biological phenomena, but they can be challenging to differentiate. Stochastic environments hamper the development of standardized monitoring schemes for wildlife, and make it more challenging to plan and evaluate the success of conservation efforts. To avoid reintroductions of species at risk that could jeopardize extant populations, managers attempting translocation events require a higher level of confidence that a failure to confirm presence represents a true absence. For many pond breeding amphibians, monitoring of the breeding population occurs indirectly through larval surveys. Larval development and successful recruitment only occurs after a sequence of appropriate environmental conditions, thus it is possible for a breeding population of adults to exist at a site but for detectability of the species to be functionally zero. We investigate how annual variability in detection influences long-term monitoring efforts of Reticulated Flatwoods Salamanders (Ambystoma bishopi) breeding in 29 wetlands in Florida. Using 8 years of historic dip net data, we simulate plausible monitoring scenarios that incorporate environmental stochasticity into estimates of detection probability. We found that annual variation in environmental conditions precluded a high degree of certainty in predicting site status for low-intensity monitoring schemes. Uncertainty was partly alleviated by increasing survey effort, but even at the highest level of sampling intensity assessed, multiple years of monitoring are required to confidently determine presence/absence at a site. Combined with assessments of habitat quality and landscape connectivity, our results can be used to identify sites suitable for reintroduction efforts. Our methodologies can be generally applied to increase the effectiveness of surveys for diverse organisms for which annual variability in detectability is known.

Assessment and Estimation of the Spatial and Temporal Evolution of Landscape Patterns and Their Impact on Habitat Quality in Nanchang, China

Assessing and predicting the evolution of habitat quality based on land use change under the process of urbanization is important for establishing a comprehensive ecological planning system and addressing the major challenges of global sustainable development. Here, two different prediction models were used to simulate the land use changes in 2025 based on the land use distribution data of Nanchang city in three periods and integrated into the habitat quality assessment model to specifically evaluate the trends and characteristics of future habitat quality changes, explore the impact of landscape pattern evolution on habitat, and analyze the differences and advantages of the two prediction models. The results show that the overall habitat quality in Nanchang declined significantly during the period 1995–2015. Habitat degradation near cities and in various watersheds is relatively significant. During the period 2015–2025, the landscape pattern and habitat quality of Nanchang will continue to maintain the trend of changes observed between 1995 and 2015, i.e., increasing construction land and decreasing habitat quality, with high pressure on ecological restoration. This study also identified that CA-Markov simulates the quantity of land use better, while FLUS simulates the spatial pattern of land use better. Overall, this study provides a reference for exploring the complex dynamic evolution mechanism of habitats.

Assessment of landscape connectivity indices and habitat quality to identify essential habitat patches for Ovis orientalis × Ovis vignei (a case study: Varjin Protected Area, Tehran)

سابقه و هدف: ارتباطات سیمای سرزمین نقش بسیار مهمی در مدیریت منطقه های حفاظت شده دارد. در منطقه حفاظت شده ورجین گونه غالب قوچ و میش البرز مرکزی است که جمعیت آن در 20 سال گذشته به دلیل تخریب زیستگاه و تکه تکه شدن در حال کاهش بوده است. تاکنون مطالعات بسیاری در رابطه با ارزیابی اثرهای محیط زیستی توسعه نقاط شهری اطراف منطقه حفاظت شده ورجین صورت گرفته است، اما هیچ مطالعه ای در رابطه با وضعیت ارتباطات و کیفیت زیستگاه در این منطقه به صورت همزمان انجام نشده است. با توجه به موقعیت قرارگیری این منطقه حفاظت شده در البرز مرکزی، یکی از راهکارهای بسیار مهم در حفاظت زیستگاه های موردنظر، بررسی ارتباطات بین لکه های زیستگاهی و شناسایی کریدورهای جابجایی گونه است. هدف از پژوهش حاضر، تحلیل مسیرهای ارتباطی بین لکه های زیستگاه قوچ و میش در منطقه حفاظت شده ورجین و در نظرگیری کیفیت زیستگاه به عنوان یکی از عامل های تأثیرگذار بر حضور بیشتر گونه در لکه های منتخب است. با استفاده از این روش می توان لکه های زیستگاهی در منطقه را در راستای حفاظت بیشتر اولویت بندی نمود.مواد و روش ها: تصویرهای ماهواره ای لندست هفت و هشت مربوط به سال 1381 و 1397 به عنوان دو نقشه پایه و زمان حال برای استفاده در مدل کیفیت زیستگاه و تحلیل ارتباطات در این پژوهش انتخاب شد. برای بررسی سنجه ارتباطات زیستگاهی در دو مقیاس لندسکیپ و لکه نیز سنجه های dBC و dPC محاسبه شد. نرم افزار مورداستفاده برای این ارزیابی، نرم افزار Graphab بوده که با استفاده از نظریه گراف به صورت شبکه ای از گره ها و مسیرها، ارتباط بین لکه های زیستگاهی را با درنظرگیری آستانه وارد شده و برمبنای روش اقلیدسی محاسبه می کند. از سوی دیگر کیفیت زیستگاه با تأثیرگذاری عامل های انسانی روی کدهای زیستگاهی در دو بازه زمانی به عنوان خدمت اکوسیستمی منطقه حفاظت شده با استفاده از نرم افزار InVEST به دست آمد. درنهایت خروجی هردو نرم افزار وارد محیط ArcGIS 10.4 شده و با طبقه بندی نرمال، طبقات ارتباطات زیستگاهی و کیفیت زیستگاه به دست آمد.نتایج و بحث: نتایج نشانگر این امر است که سنجه dPC در بازهای بین 0 تا 796 / 0 و سنجه dBC در بازه 0 تا 11 + E 58 / 7 به دست آمده است. این مقادیر در محیط ArcGIS ، به 5 گروه متفاوت اهمیت تقسیم شدند و 23 لکه زیستگاهی هرکدام درجه متفاوتی از اهمیت را به خود اختصاص دادند. دو لکه یک و چهار در سمت راست منطقه حفاظت شده اهمیت بسیار زیادی در حفظ دو سنجه dBC و dPC دارند . همچنین خروجی مدل InVEST نشان می دهد کیفیت زیستگاه در نواحی شمال و شمال شرقی منطقه در طبقات کم و در جنوب منطقه نیز در طبقه بسیار کم قرارگرفته است. با اولویت بندی دو نقشه ارتباطات و کیفیت زیستگاه، لکه های زیستگاهی دارای اولویت حفاظت به دست آمد که لکه های سمت شرقی و جنوبی منطقه را تشکیل می دهند.نتیجه گیری: لکه هایی که ازلحاظ ارتباطات اهمیت ویژه ای داشته و همچنین دارای کیفیت زیستگاه بهتری نسبت به سایر لکه های دیگر است، در قسمت شرق و جنوب شرقی منطقه حفاظت شده ورجین قرار گرفت. این مطالعه با قدمی نوین و با استفاده از سنجه های ارتباطی در دو مقیاس لندسکیپ و لکه و با در نظرگیری خدمت اکوسیستمیِ کیفیت زیستگاه به شناسایی لکه های دارای اهمیت در طرح حفاظتی پرداخته و می تواند برای دیگرگونه های سنجه در مناطق حفاظت شده مورداستفاده قرارگیرد. به طورقطع با تغییر مقیاس مطالعه و در نظرگیری دو منطقه حفاظت شده لار و البرز مرکزی در دو سوی ورجین، نتایج مطالعات ارتباطات و درنهایت اولویت بندی تغییر خواهد کرد.

Pheromone communication among sexes of the garden cross spider Araneus diadematus

Chemical communication plays a fundamental role in many aspects of an animal’s life from assessing habitat quality to finding mating partners. Behavioural observations show that chemical communication likewise plays an important role in spiders, but the contexts and the substances involved are little explored. Here, we investigate the chemical communication in the garden cross spider Araneus diadematus (Clerck, 1757) between and within the sexes. Using choice trials, we demonstrate that males are attracted to odours of adult females, but not to those of subadult females. Our data further suggest that adult females avoid odours of conspecific adult females, possibly in order to reduce reproductive competition with other females. Cuticle and silk extracts as well as headspace samples of subadult and adult virgin females were analysed via GC–MS. Available candidate compounds for the female sex pheromone were tested via electroantennography on palps (electropalpography) of adult virgin females and on females in behavioural trials. We propose sulcatone (6-methyl-5-hepten-2-one) as a candidate substance for the female volatile pheromone and several long-chained alkanes and alcohols as candidates for contact pheromones. Apart from demonstrating that attraction of males to females depends on the latter’s developmental stage, our study suggests that pheromones can also play an important role between females, an aspect that requires further attention.

Alarming decline of freshwater trigger species in western Mediterranean key biodiversity areas

Theidentification of key biodiversity areas (KBA) was initiated by the International Union for Conservation of Nature in 2004 to overcome taxonomic biases in the selection of important areas for conservation, including freshwater ecosystems. Since then, several KBAs have been identified mainly based on the presence of trigger species (i.e., species that trigger either the vulnerability and or the irreplaceability criterion and thus identify a site as a KBA). However, to our knowledge, many of these KBAs have not been validated. Therefore, classical surveys of the taxa used to identify freshwater KBAs (fishes, molluscs, odonates, and aquatic plants) were conducted in Douro (Iberian Peninsula) and Sebou (Morocco) River basins in the Mediterranean Biodiversity Hotspot. Environmental DNA analyses were undertaken in the Moroccan KBAs. There was a mismatch between the supposed and actual presence of trigger species. None of the trigger species were found in 43% and 50% of all KBAs surveyed in the Douro and Sebou basins, respectively. Shortcomings of freshwater KBA identification relate to flawed or lack of distribution data for trigger species. This situation results from a misleading initial identification of KBAs based on poor (or even inaccurate) ecological information or due to increased human disturbance between initial KBA identification and the present. To improve identification of future freshwater KBAs, we suggest selecting trigger species with a more conservative approach; use of local expert knowledge and digital data (to assess habitat quality, species distribution, and potential threats); consideration of the subcatchment when delineating KBAs boundaries; thoughtful consideration of terrestrial special areas for conservation limits; and periodic field validation.