scholarly journals Predicting Harbor Porpoise Strandings Based on Near-Shore Sightings Indicates Elevated Temporal Mortality Rates

2021 ◽  
Vol 8 ◽  
Author(s):  
Lonneke L. IJsseldijk ◽  
Kees C. J. Camphuysen ◽  
Guido O. Keijl ◽  
Gerard Troost ◽  
Geert Aarts

The increase in anthropogenic activities and their potential impact on wildlife requires the establishment of monitoring programs and identification of indicator species. Within marine habitats, marine mammals are often used as ecosystem sentinels, which has led to investigations into their abundance, distribution, and mortality patterns. However, trends in sightings and strandings are rarely analyzed in combination. This is necessary to distinguish elevated stranding rates caused by changes in local abundance from increased mortality as a consequence of other natural, environmental or anthropogenic factors. Therefore, the objective of this study was to assess whether harbor porpoise (Phocoena phocoena) stranding frequency in the southern North Sea can be explained by local population density derived from more than 400 thousand hours of systematic observations along the Dutch coast between 1990 and 2018. Since the late 1990s, both the number of stranded porpoises and the sighting rate increased rapidly up to around the mid-2000s, after which they remained high, but with large inter-annual fluctuations. On an annual basis there was a strong correlation between porpoise strandings and sightings, but with a seasonal mismatch. Highest stranding rates occur in late summer, while highest sighting rates occur in early spring. Despite low sighting rates in late summer, August appears to be the best predictor for the monthly variation in the number of stranded porpoises, which could be explained by post-reproductive dispersal and mortality. Excessive high porpoise stranding numbers after accounting for variations in local density could signpost unusual mortality events (UMEs). The corrected stranding rates show that in the early 1990s, when porpoise sightings were rare, and after 2010, the number of stranded porpoises exceeds the expected number. Especially in the summer of 2011, the number of dead porpoises found ashore was excessively high and this might reflect an UME. These results demonstrate that a comparative interpretation of marine mammal strandings and coastal sightings can be a valuable management and conservation tool that could provide an early warning signal for population change.

2018 ◽  
Vol 12 (7-8) ◽  
pp. 38-45
Author(s):  
A. N. EFREMOV ◽  
N. V. PLIKINA ◽  
T. ABELI

Rare species are most vulnerable to man-made impacts, due to their biological characteristics or natural resource management. As a rule, the economic impact is associated with the destruction and damage of individual organisms, the destruction or alienation of habitats. Unfortunately, the conservation of habitat integrity is an important protection strategy, which is not always achievable in the implementation of industrial and infrastructural projects. The aim of the publication is to summarize the experience in the field of protection of rare species in the natural habitat (in situ), to evaluate and analyze the possibility of using existing methods in design and survey activities. In this regard, the main methodological approaches to the protection of rare species in the natural habitat (in situ) during the proposed economic activity were reflected. The algorithm suggested by the authors for implementing the in situ project should include a preparatory stage (initial data collection, preliminary risk assessments, technology development, obtaining permitting documentation), the main stage, the content of which is determined by the selected technology and a long monitoring stage, which makes it possible to assess the effectiveness of the taken measures. Among the main risks of in situ technology implementation, the following can be noted: the limited resources of the population that do not allow for the implementation of the procedure without prior reproduction of individuals in situ (in vitro); limited knowledge of the biology of the species; the possibility of invasion; the possibility of crossing for closely related species that сo-exist in the same habitat; social risks and consequences, target species or population may be important for the local population; financial risks during the recovery of the population. The available experience makes it possible to consider the approach to the conservation of rare species in situ as the best available technology that contributes to reducing negative environmental risks.


2017 ◽  
Vol 68 (8) ◽  
pp. 1744-1748
Author(s):  
Catalina Stoica ◽  
Gabriela Geanina Vasile ◽  
Alina Banciu ◽  
Daniela Niculescu ◽  
Irina Lucaciu ◽  
...  

During the past few decades, the anthropogenic activities induced worldwide changes in the ecological systems, including the aquatic systems. This work analysed the contamination level of groundwater resources from a rural agglomeration (Central-Western part of Prahova County) by biological and physico-chemical approaches. The study was performed during the autumn of 2016 on several sampling sites (four drilling wells, depth higher than 100 m supplying three villages; two wells lower than 10 m depth and one spring). The water quality was evaluated by comparison with the limit values of the drinking water quality legislation (Law no.458/2002) and the Order 621/2014 (applicable to all groundwater bodies of Romania). The results showed that phenols and metals (iron and manganese) exceeded the threshold values in all sampling sites. Moreover, the anthropogenic factors including agriculture, use of fertilizers, manures, animal husbandry led to an increase of the bacterial load, particularly at wells sites.


Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1636
Author(s):  
Thanh N. Le ◽  
Duy X. Tran ◽  
Thuong V. Tran ◽  
Sangay Gyeltshen ◽  
Tan V. Lam ◽  
...  

Saltwater intrusion risk assessment is a foundational step for preventing and controlling salinization in coastal regions. The Vietnamese Mekong Delta (VMD) is highly affected by drought and salinization threats, especially severe under the impacts of global climate change and the rapid development of an upstream hydropower dam system. This study aimed to apply a modified DRASTIC model, which combines the generic DRASTIC model with hydrological and anthropogenic factors (i.e., river catchment and land use), to examine seawater intrusion vulnerability in the soil-water-bearing layer in the Ben Tre province, located in the VMD. One hundred and fifty hand-auger samples for total dissolved solids (TDS) measurements, one of the reflected salinity parameters, were used to validate the results obtained with both the DRASTIC and modified DRASTIC models. The spatial analysis tools in the ArcGIS software (i.e., Kriging and data classification tools) were used to interpolate, classify, and map the input factors and salinization susceptibility in the study area. The results show that the vulnerability index values obtained from the DRASTIC and modified DRASTIC models were 36–128 and 55–163, respectively. The vulnerable indices increased from inland districts to coastal areas. The Ba Tri and Binh Dai districts were recorded as having very high vulnerability to salinization, while the Chau Thanh and Cho Lach districts were at a low vulnerability level. From the comparative analysis of the two models, it is obvious that the modified DRASTIC model with the inclusion of a river or canal network and agricultural practices factors enables better performance than the generic DRASTIC model. This enhancement is explained by the significant impact of anthropogenic activities on the salinization of soil water content. This study’s results can be used as scientific implications for planners and decision-makers in river catchment and land-use management practices.


Author(s):  
Ines Khedhri ◽  
Hanem Djabou ◽  
Ahmed Afli

The lagoon of Boughrara is the largest lagoon in Tunisia. For several decades it has been subject to the impact of increasing anthropogenic activities, and also to environmental stressors due to climate change and the low renewal of its waters. The present work is a contribution to the study of the functional organization of the benthic macrofauna of the lagoon of Boughrara 3 years after the extension of the channel ‘El Kantra’ which connects this lagoon to the open sea. In total, 13 stations facing the main prospective sources of disturbance and in areas likely to be more polluted were seasonally sampled during 2009–2010. Seasonal monitoring of the abiotic parameters shows a spatial heterogeneity linked to environmental and anthropogenic factors, including hydrodynamics, sedimentary texture and anthropogenic activities. The community of benthic macrofauna is generally poorly diversified at lagoonal-marine stations undergoing influences of both the marine and lagoon environment. The extreme seasons in terms of temperature and salinity seem to have an important role in the reduction of biodiversity in the lagoon of Boughrara. The trophic structure of the macrobenthic community is generally dominated by selective deposit feeders, and seems to be linked more to the availability of trophic resources than to disturbance.


2018 ◽  
Vol 7 (1) ◽  
pp. 37-41
Author(s):  
Valentina Nikolaevna Ilina

This paper examines features of the demographic structure of natural populations of a rare representative of the steppe flora Astragalus cornutus Pall. (Fabaceae). The rarity of the species makes it necessary to include it in the Red Books of the Russian Federation and some steppe regions. In the Samara Region, species populations require additional protection in connection with the peculiarities of biology and ecology, a significant anthropogenic load on communities, and a reduction in the number of habitats. We studied the features of the structure of populations in the Samara Trans-Volga Region. A total of 84 cenopopulations were surveyed, tendencies of population change, features of demographic and spatial structure were revealed. The structure of populations is affected by the ecological and phytocenotic conditions of the environment and anthropogenic factors. The replacement and recovery of individuals in A. cornutus populations is slow. The ontogenetic structure of populations has a fluctuation dynamics. Assessment of the studied geographical populations by L.A. Zhivotovsky efficiency criterion (2001) showed that they are all mature. Specific cenopopulations of A. cornutus are aging (5%) and old (8%). The average density of individuals is about 3 individuals/m. The average effective density is 2,4 individuals/m, the largest - 4,1, the smallest - 1,3. The condition of all studied populations (even in a satisfactory state) on the territory of the Samara Region causes alarm. Populations of the species in the region need additional protection measures.


2017 ◽  
Vol 4 (1) ◽  
pp. 53-54
Author(s):  
Karthikeyan P

The novel speaks about the efforts taken by Piyali Roy, an Indian American biologist to make a study on marine mammals, especially on Irrawaddy dolphins.The novel is set in Sundarbans. Piya arrives at Sundarbans which is considered by her as a suitable place for carrying out her study. She lands on an island in Sunderbans and gets acquainted with an inhabitant of that place named Fokir. He remains to be a guide for her and instructs her about the marine habitats. Fokir being a resident of that place, he knows about the tides occurrence in the seas and the perils. Though he knows these, to the dismay of the readers, Fokir dies when a storm breaks out followed by heavy rain and powerful and devouring tides. As ideas given by Fokir could be the sources for decades of ‘research’,with the sponsorship of Nilima and involvement of local fisherman, Piya starts an institution in the memory of Fokir. The novel deals with the dislocation of people due to tide. Tide causes great havoc to the life and property of the inhabitants of the islands in Sunderbans. The poor people who have become victims of natural catastrophe suffer from hunger. I would like to bring out the human environmental relationship in the novel. Human beings depend on nature and environment. Eco Criticism on this novel helps to evaluate this literary text in the literature and environment perspective.


2011 ◽  
Vol 2 (2) ◽  
pp. 125-134 ◽  
Author(s):  
W. Mark Ford ◽  
Eric R. Britzke ◽  
Christopher A. Dobony ◽  
Jane L. Rodrigue ◽  
Joshua B. Johnson

Abstract White-nose Syndrome (WNS), a wildlife health concern that has decimated cave-hibernating bat populations in eastern North America since 2006, began affecting source-caves for summer bat populations at Fort Drum, a U.S. Army installation in New York in the winter of 2007–2008. As regional die-offs of bats became evident, and Fort Drum's known populations began showing declines, we examined whether WNS-induced change in abundance patterns and seasonal timing of bat activity could be quantified using acoustical surveys, 2003–2010, at structurally uncluttered riparian–water habitats (i.e., streams, ponds, and wet meadows). As predicted, we observed significant declines in overall summer activity between pre-WNS and post-WNS years for little brown bats Myotis lucifugus, northern bats M. septentrionalis, and Indiana bats M. sodalis. We did not observe any significant change in activity patterns between pre-WNS and post-WNS years for big brown bats Eptesicus fuscus, eastern red bats Lasiurus borealis, or the small number of tri-colored bats Perimyotis subflavus. Activity of silver-haired bats Lasionycteris noctivagans increased from pre-WNS to post-WNS years. Activity levels of hoary bats Lasiurus cinereus significantly declined between pre- and post-WNS years. As a nonhibernating, migratory species, hoary bat declines might be correlated with wind-energy development impacts occurring in the same time frame rather than WNS. Intraseason activity patterns also were affected by WNS, though the results were highly variable among species. Little brown bats showed an overall increase in activity from early to late summer pre-WNS, presumably due to detections of newly volant young added to the local population. However, the opposite occurred post-WNS, indicating that reproduction among surviving little brown bats may be declining. Our data suggest that acoustical monitoring during the summer season can provide insights into species' relative abundance on the landscape as affected by the occurrence of WNS.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Katherine C. Kendall ◽  
Tabitha A. Graves ◽  
J. Andrew Royle ◽  
Amy C. Macleod ◽  
Kevin S. McKelvey ◽  
...  

AbstractTrends in population abundance can be challenging to quantify during range expansion and contraction, when there is spatial variation in trend, or the conservation area is large. We used genetic detection data from natural bear rubbing sites and spatial capture-recapture (SCR) modeling to estimate local density and population growth rates in a grizzly bear population in northwestern Montana, USA. We visited bear rubs to collect hair in 2004, 2009—2012 (3,579—4,802 rubs) and detected 249—355 individual bears each year. We estimated the finite annual population rate of change 2004—2012 was 1.043 (95% CI = 1.017—1.069). Population density shifted from being concentrated in the north in 2004 to a more even distribution across the ecosystem by 2012. Our genetic detection sampling approach coupled with SCR modeling allowed us to estimate spatially variable growth rates of an expanding grizzly bear population and provided insight into how those patterns developed. The ability of SCR to utilize unstructured data and produce spatially explicit maps that indicate where population change is occurring promises to facilitate the monitoring of difficult-to-study species across large spatial areas.


2018 ◽  
Vol 99 (5) ◽  
pp. 1075-1086 ◽  
Author(s):  
Nur Eda Topçu ◽  
Emre Turgay ◽  
Remziye Eda Yardımcı ◽  
Bülent Topaloğlu ◽  
Ahsen Yüksek ◽  
...  

AbstractA massive die-off of benthic suspension feeders (BSF) covered by large amounts of sediments was observed along Prince Islands coasts (north-eastern Sea of Marmara) in August 2015. Alcyonarians, pennatulaceans, bivalves and sponges were severely affected. Many BSF probably died from burial and clogging of their feeding and respiratory apparatus. Of the gorgonian colonies, 66 ± 34% (mean ± SD) were dead, while 15 ± 16% (mean ± SD) displayed recent necrosis on the colony surface. In addition, histopathological and microbial examinations of the affected gorgonians and gold corals (Savalia savaglia) suggest that stress caused by sedimentation made them vulnerable to exploitation by consistently isolated opportunistic microorganisms. We isolatedVibrio splendidusandVibrio neptuniusfrom diseased gold coral colonies, but the bacterial isolates obtained from gorgonians could only be identified to genusVibriolevel. The presumably artificially introduced fungusMucor circinelloideswas common on both gold coral and gorgonians. This mould and opportunistic bacteria may have colonized BSF by taking advantage of low oxygen levels leading to impaired coral immune responses and thereby exacerbated the BSF mortality. Construction and landfill operations at Yassıada seem to be the greatest contributor to the observed sedimentation, as shown by silicate concentrations in nearby waters. These observations imply that preventive measures are necessary when construction operations take place in the vicinity of sensitive marine habitats.


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