POPULATION TREND OF THE INVASIVE BLUE CRAB CALLINECTES SAPIDUS RATHBUN,1896 IN PATOKU LAGOON.

The blue crab Callinectes sapidus is one of the 23 marine alien species reported for the Albanian coast so far (Beqiraj et al., 2012; Katsanevakis et al., 2011). The first scientific report on the presence of this species in the Albanian coast is in 2009, in Patoku Lagoon. The blue crab population in Patoku Lagoon had grown significantly by 2009 and the blue crab had started to be traded. The data collected in that year showed that this species is assessed to be established in the Patoku Lagoon (Beqiraj & Kashta, 2010). Special attention has been paid to the study of blue crab population in the following years during 2010 - 2015. The aim of this study is to evaluate the development and population trend of blue crab in the Patoku Lagoon referring to the data collected throughout years of study.

Landscape Attributes Best Explain the Population Trend of Wintering Greater White-Fronted Goose (Anser albifrons) in the Yangtze River Floodplain

Biodiversity in the Middle and Lower Yangtze Floodplain has critically decreased during the last several decades, driven by numerous determinants. Hence, identification of primary drivers of animal population decline is a priority for conservation. Analyzing long time-series data is a powerful way to assess drivers of declines, but the data are often missing, hampering effective conservation policymaking. In this study, based on twenty-four years (from 1996 to 2019) of annual maximal count data, we investigated the effects of climate and landscape changes on the increasing population trend of the Greater White-Fronted Goose (Anser albifrons) at a Ramsar site in the Middle and Lower Yangtze Floodplain, China. Our results showed that the availability of a suitable habitat and landscape attributes are the key driving forces affecting the population trend, while the effects of climate factors are weak. Specifically, increasing the area of suitable habitat and alleviating habitat fragmentation through a fishing ban policy may have provided a more suitable habitat to the geese, contributing to the increasing population trend. However, we also observed that the grazing prohibition policy implemented in 2017 at Shengjin Lake may have potentially negatively affected geese abundance, as grazing by larger herbivores may favor smaller geese species by modifying the vegetation community and structure. Based on our results, we suggest several practical countermeasures to improve the habitat suitability for herbivorous goose species wintering in this region.

Is the global decline reflects local declines? A case of the population trend of Far Eastern Curlew Numenius madagascariensis in Banyuasin Peninsula, South Sumatra, Indonesia

Far Eastern Curlew Numenius madagascariensis (Linnaeus, 1766) is Endangered species confined in East Asian Australasian Flyway (EAAF) sites. We compiled and summarized all historical numbers of Far Eastern Curlew in Banyuasin Peninsula, South Sumatra, Indonesia. A total of 30 records were documented from 1984 to 2020. The largest number is 2,620 individuals during the migration period in 1988. Unfortunately, the largest number drop to 1,750 individuals in wintering period in 2008, and then drop to 850 individuals in 2019. The numbers indicate that the population decline by up to 62% in the last 35 years (1984 to 2019). It is clear that the global decline of the Far Eastern Curlew also reflects the local population decline in Banyuasin Peninsula.

Status of Red-headed Vulture (Sarcogyps calvus) in Bundelkhand Region, India

Vultures are excellent indicators of environmental health and as carrion feeders play an important ecological role. They are the only known vertebrate obligate scavengers. Nine different species of old world vultures are found in India. Red-headed Vulture (RHV) is one of the resident vulture species and is found throughout the country up to 2000 m elevation. This study was carried out in two states of India, Uttar Pradesh and Madhya Pradesh known as Bundelkhand. The grids of 15x15 sq km and random points were laid over the study area. Transects of 10 km were conducted in all the selected grids. As a result, 46, 54 and 74 vultures were recorded from 2017 to 2019, respectively. There was a continuous rise in the RHV population during the study period, which is a good sign for the species. Along with other vulture species, RHV is also facing serious threats. Biotic and abiotic threats such as habitat loss, predation, hunting and disturbance, scarcity of food and water, change in land use and agricultural practices, poisoning and, mortality in road accidents while feeding. The population trend is showing positive signs but only regular monitoring and conservation activities will help in saving the species.

Shifting trends: Detecting changes in cetacean population dynamics in shifting habitat

The ability to monitor population dynamics and detect major changes in population trend is essential for wildlife conservation and management. However, this is often challenging for cetaceans as surveys typically cover only a portion of a population’s range and conventional stock assessment methods cannot then distinguish whether apparent changes in abundance reflect real changes in population size or shifts in distribution. We developed and tested methods for estimating population size and trend and detecting changes in population trend in the context of shifting habitat by integrating additional data into distance-sampling analysis. Previous research has shown that incorporating habitat information can improve population size estimates for highly mobile species with dynamic spatial distributions. Here, using simulated datasets representative of a large whale population, we demonstrate that incorporating individual mark-recapture data can increase the accuracy and precision of trend estimation and the power to distinguish whether apparent changes in abundance reflect changes in population trend or distribution shifts. We recommend that similar simulation studies are conducted for specific cetacean populations to assess the potential for detecting changes in population dynamics given available data. This approach is especially important wherever population change may be confounded with long-term change in distribution patterns associated with regime shifts or climate change.

How animals distribute themselves in space: energy landscapes of Antarctic avian predators

Background Energy landscapes provide an approach to the mechanistic basis of spatial ecology and decision-making in animals. This is based on the quantification of the variation in the energy costs of movements through a given environment, as well as how these costs vary in time and for different animal populations. Organisms as diverse as fish, mammals, and birds will move in areas of the energy landscape that result in minimised costs and maximised energy gain. Recently, energy landscapes have been used to link energy gain and variable energy costs of foraging to breeding success, revealing their potential use for understanding demographic changes. Methods Using GPS-temperature-depth and tri-axial accelerometer loggers, stable isotope and molecular analyses of the diet, and leucocyte counts, we studied the response of gentoo (Pygoscelis papua) and chinstrap (Pygoscelis antarcticus) penguins to different energy landscapes and resources. We compared species and gentoo penguin populations with contrasting population trends. Results Between populations, gentoo penguins from Livingston Island (Antarctica), a site with positive population trends, foraged in energy landscape sectors that implied lower foraging costs per energy gained compared with those around New Island (Falkland/Malvinas Islands; sub-Antarctic), a breeding site with fluctuating energy costs of foraging, breeding success and populations. Between species, chinstrap penguins foraged in sectors of the energy landscape with lower foraging costs per bottom time, a proxy for energy gain. They also showed lower physiological stress, as revealed by leucocyte counts, and higher breeding success than gentoo penguins. In terms of diet, we found a flexible foraging ecology in gentoo penguins but a narrow foraging niche for chinstraps. Conclusions The lower foraging costs incurred by the gentoo penguins from Livingston, may favour a higher breeding success that would explain the species’ positive population trend in the Antarctic Peninsula. The lower foraging costs in chinstrap penguins may also explain their higher breeding success, compared to gentoos from Antarctica but not their negative population trend. Altogether, our results suggest a link between energy landscapes and breeding success mediated by the physiological condition.

Combination of targeted monitoring and Breeding Bird Survey data improves population trend estimation and species distribution modeling for the Common Nighthawk

Standardized monitoring is critical for conservation because reliable survey data are used to inform the necessity, type, and effectiveness of conservation actions. Many of the avian monitoring data used for conservation are collected by “comprehensive” programs that survey for all species observed; however, there are some species that have low availability for detection during comprehensive surveys and are instead monitored with targeted programs. Unfortunately, those targeted programs are rarely evaluated relative to existing programs and management objectives to inform allocation of effort. We assessed the statistical performance of the comprehensive North American Breeding Bird Survey (BBS), the targeted Canadian Nightjar Survey (CNS), and the two programs combined for the Common Nighthawk (Chordeiles minor). First, we used parameters from the existing datasets to simulate population declines and determined the probability of detecting those declines. Analyses that combined both datasets resulted in higher probability of detecting a 30% population decline (BBS: 38%, CNS: 64%, combined: 69%). Next, we built probability of occurrence models and assessed the predictive performance of those models. Combined analyses had similar predictive performance to the CNS and moderated poor performance of the BBS in the north (mean Cohen’s kappa; BBS: 0.40, CNS: 0.46, combined: 0.50). Our results suggest that data from targeted monitoring is important for evaluation of Common Nighthawk population trend and habitat relationships but is best combined with BBS data. Comprehensive and targeted monitoring programs may be better when considered together, and exploration of data combination should become the rule, not the exception. We suggest that the framework we present can be used as a starting point for evaluating targeted monitoring programs relative to defined objectives and existing programs, with the potential to explore hypothetical management scenarios.

Seasonal abundance and diversity of spiders (Arachnida: Araneae) in rice ecosystem of Himachal Pradesh

Spiders are one of the most fascinating and diverse invertebrates and also potential bio-control agents in agro-ecosystems. Field surveys were carried out at Sundernagar, Jogindernagar, Nurpur and Palampur areas of Himachal Pradesh by two methods namely visual count and sweep net to assess seasonal abundance and diversity of spider, in the rice ecosystems during kharif, 2015 and 2016. It was found that the population trend was well represented by visual count method as compared to sweep net method. Maximum numbers of spiders were recorded from Palampur area followed by Sundernagar, Jogindernagar and Nurpur. Eleven families viz., Oxyopidae, Tetragnathidae, Salticidae, Lycosidae, Pisauridae, Araneidae, Theridiidae, Clubionidae, Sparassidae, Thomisidae and Pholcidae were recorded from the fields with majority belonging to Araneidae and Tetragnathidae. The pre-dominant spider genus from all the locations were Tetragnatha and Neoscona while Araneus pseudosturmii and Runcinia ghorpadei Tikader were confined only to Nurpur and Sundernagar, respectively. A. pseudosturmii and Micropholcus fauroti Simon seem to be the first records from India while R. ghorpadei to be the hitherto unknown male morph.