Sand Digging Research Articles

Effect of noise on sand digging and emergence activities in green turtle (Chelonia mydas) hatchlings

Anthropogenic noise affects animal behavior and physiology. However, relatively few studies have been conducted on the effects of noise on beach-associated animals. This study evaluated the effects of noise on sound emission, sand digging activity, and emergence from the sand surface by green turtle (Chelonia mydas) hatchlings. Acoustic recorders and infrared cameras were used to investigate the behavior of hatchlings in sand-filled chambers under three acoustic conditions: 1) a control treatment, which was silent throughout the experiment; 2) an environmental noise treatment, which exposed the hatchlings to white noise (WN) at a sound pressure level (SPL) approximately 13 dB higher than that of the control, which is similar to that of a natural beach; and 3) a loud noise treatment, which exposed them to WN at an SPL approximately 25 dB higher than that of the control. The WN ranged from 0 to 4 kHz with a repeating cycle of 30 min sound emission and 2 h 30 min silence. Sound emissions from green turtle hatchlings were detected; however, the amount of sound emissions was too small to discuss their ecological significance. The time to emergence and total number of digging bouts in the 24 h pre-emergence periods were not significantly different among treatments; however, the number of digging bouts was significantly higher during loud noise exposure. The response to loud noises may play a role in allowing hatchlings to escape from threats and/or coordinate synchronous behavior among multiple individuals. However, because the number of digging bouts decreased after loud noise exposure, prolonged exposure to loud noise may have detrimental effects on hatchlings, such as depletion of the energy reserves available to the hatchlings. Thus, anthropogenic noise on or around beaches and it effect on animals should be carefully considered.

Illegal and Exploitative Sand-Digging Activities Could Be Managed to Create Suitable Nesting Habitats for Blue-Tailed Bee-Eaters (Merops philippinus)

The development of human society often interferes with wild animals and their natural habitats. Interference during resource exploitation is mostly negative; however, in some cases, it can be positive and even have significance for some species. In this study, we investigated the number of blue-tailed bee-eaters (Merops philippinus), a species under 'state protection category II' in China, between controlled and manipulated nesting habitats from 2017 to 2022. Our results indicated that commercial sand-digging activities, either illegal or approved, initially created suitable nesting habitats to attract blue-tailed bee-eaters but subsequently led to damage of nests or nesting habitats. However, sand digging can be modified by avoiding the breeding season to provide safe and suitable nesting habitats for bee-eaters. The number of breeding birds more than tripled when digging during the breeding season was avoided. We also found that conventional conservation strategies, which strictly prohibited sand-digging activities, did not contribute to the nesting habitats of bee-eaters. This study enriches the theories of conservation biology and emphasizes the importance of dialectical thinking regarding exploitative and seemingly destructive activities.

Cooperative breeding in Neolamprologus bifasciatus , a cichlid fish inhabiting the deep reefs of Lake Tanganyika

Cooperative breeding, a social system in which offspring receive care from other group members as well as their parents, occurs in insects, fish, birds and mammals. In this study, we report a new example of cooperative breeding in the cichlid fish (Neolamprologus bifasciatus). This species, endemic to Lake Tanganyika, Africa, inhabits rocky areas at depths below 30 m. Observations of eight nests using underwater video cameras showed that one to six subordinates were present in the nests of breeding pairs. The subordinates shared shelters with juveniles and breeders and engaged in brood/territorial defence and nest maintenance (removing sand from the nest), albeit at a lower frequency than female breeders. The frequency of sand digging by subordinates and female breeders decreased as the number of subordinates in the group increased, suggesting that subordinates reduce the costs of nest maintenance for breeders. The male breeders seldom showed territorial defence and nest maintenance. Subordinates exhibited submissive behaviours towards dominant breeders and larger subordinates within their breeding group, indicating a dominance hierarchy among group members. Gonad examination revealed that the subordinates of both sexes were sexually immature, suggesting that they may not participate in reproduction. An aquarium experiment showed that juveniles become subordinates in their natal nest and participate in territory defence. We conclude that N. bifasciatus is a cooperative breeder, with social systems and subordinate roles similar to those observed in other cooperatively breeding cichlids.

Fog composition along the Yangtze River basin: Detecting emission sources of pollutants in fog water

To investigate the fog chemistry along the Yangtze River basin, a field observation experiment was performed from Shanghai to Wuhan during November 2015. Fifteen fog water samples were collected by using a three-stage Caltech Active Strand Cloud water Collector (CASCC). The three-stage CASCC was mounted on the board of a ship. PH, electrical conductivity (EC), H2O2, HCHO, S(IV), ten inorganic ions, seven organicacids and sixteen trace metal elements were measured in this study. The pH of fog water samples ranged from weakly acidic (pH4.3) to weakly alkaline (pH7.05) and the EC ranged from 32.4 to 436.3μS/cm. The main cations in fog water were NH4+ and Ca2+, accounting for 12.35% and 29.07% of those inorganic ions, respectively. In addition, SO42− and NO3− contributed to 25.52% and 12.93% to total anion concentrations respectively. Moreover, the dominant kinds of organicacids were formate and oxalate, occupying 45.28% and 28.03% of the total organicacids, respectively. For trace metal elements in fog samples, Al, Fe, Zn, and Ba revealed 34.6%, 16.4%, 19.3%, and 20.9% contributions to these sixteen trace element concentrations, respectively. The results indicated that pollutants were mainly from human activities, including fossil fuel combustion, biomass burning, steel-making, stone quarrying and sand digging. Besides, natural sources including natural background levels and long-range transport of sea salt particles also aggravated the pollution levels in the fog events along the Yangtze River.

Organization of rescue behaviour sequences in ants, Cataglyphis cursor, reflects goal-directedness, plasticity and memory

The experimental study of rescue behaviour in ants, behaviour in which individuals help entrapped nestmates in distress, has revealed that rescuers respond to victims with very precisely targeted behaviour. In Cataglyphis cursor, several different components of rescue behaviour have been observed, demonstrating the complexity of this behaviour, including sand digging and sand transport to excavate the victim, followed by pulling on the victim’s limbs as well as the object holding the victim in place, behaviour that serves to free the victim. Although previous work suggested that rescue was optimally organized, first to expose and then to extricate the victim under a variety of differing circumstances, experimental analysis of that organization has been lacking. Here, using experimental data, we characterize the pattern of individual rescue behaviour in C. cursor by analysing the probabilities of transitions from one behavioural component to another. The results show that the execution of each behavioural component is determined by the interplay of previous acts. In particular, we show not only that ants move sand away from the victim in an especially efficient sequence of behaviour that greatly minimizes energy expenditure, but also that ants appear to form some kind of memory of what they did in the past, a memory that directs their future behaviour.

SIMULATION STUDY ON THE EFFECT OF SAND DIGGING AND HEAPING ON SAR IMAGING IN THE PEARL RIVER ESTUARY

Abstract. There are frequent sand digging and heaping activities in shoal in the Pearl River Estuary (PRE). Water depth has changed in patches, which can be imaged by synthetic aperture radar (SAR). According to SAR imaging mechanism of underwater bathymetry, a 3-D hydrodynamic model is used to demonstrate the temporal variations of the shoal topography changes due to sand digging and heaping. A microwave radar imaging of oceanic surface’s program is used to simulate the variation of normalized radar cross section (NRCS) induced by the ocean surface current. The simulation is carried out to study the digging-heaping shape, water depth changes on SAR imaging of shoal bathymetry. Results indicate several points as followings. 1. Circle-shaped sand digging and heaping are imaged clearer by SAR than other shapes. 2. Sand heaping has a greater effect on SAR imaging than sand digging. 3. Bigger depth change induces bigger NRCS variation.

A comparative analysis of precision rescue behaviour in sand-dwelling ants

A sand-dwelling Mediterranean ant, Cataglyphis cursor, recently was discovered to engage in two new forms of rescue behaviour, behavioural patterns that require would-be rescuers to recognize what, exactly, holds nestmates in place. That is, when sand digging and limb pulling, two well-known forms of rescue in ants, did not result in release of victims ensnared with nylon thread and partially buried beneath the sand, rescuers next began to transport sand away from the snare and to direct their behaviour to the snare in particular, biting and tugging at the snare itself. To determine whether these new forms of precisely directed rescue behaviour, as well as their exclusive delivery to nestmates, as in C. cursor, were characteristic of other ants occupying similar ecological niches, we conducted experiments with five sand-dwelling Mediterranean ant species: Cataglyphis floricola, Lasius grandis, Aphaenogaster senilis, Messor barbarus and Messor marocanus. Our experiments revealed the full range of rescue behaviour, including snare biting and sand transport, in two species, C. floricola and L. grandis. Both species directed rescue exclusively towards nestmates, treating other individuals, even conspecifics, with aggression, thus highlighting the ants' discriminative capacities. Differences in the performance of rescue behaviour between these and the remaining species mirror differences in their ecology, including the threat of predatory antlions. Finally, because this precisely directed and exclusively delivered rescue behaviour in ants resembles behaviour that has been labelled empathy in rats, our results demonstrate that what can appear to be complex, cognitively motivated behaviour might come about through much simpler mechanisms.

Livelihoods and environmental challenges in coastal communities of Nigeria

Several socio-economic activities such as construction, farming, gas flaring, oil exploration and transportation have affected the physical environment in Nigeria. These activities constitute major sources of revenue for the majority of Nigerians. Yet, there is disconnection between adverse consequences of the above-mentioned socio-economic activities and the need to protect the environment. Though Nigerian governments have established environmental protection agencies, environmental challenges remain high in Nigeria. This situation can be adduced to several years of neglect and poor socio-economic conditions in Nigeria where people largely contravene environmental laws with impunity in their struggle for survival. How do socio-economic activities influence the coastal environment in Nigeria? What are local contributions to environmental protection in Nigeria? These questions were addressed within interpretive theories complemented by 32 Focus Group Discussions among youth and community leaders in eight coastal communities in Lagos State of Nigeria. Respondents were purposively selected from the coastal communities in Lagos State, Nigeria. Results showed a consensus on the dilemma in socio-economic activities of coastal communities with minor variations. Fishing, farming, sand digging and trading were popular occupations in the study areas. Dissenting views were expressed concerning implications of socio-economic activities on the coastal environment. Fishermen claimed that sand digging created hindrances to fishing activities, while sand diggers complained about pollution associated with chemicals found on the water. Farmers confessed that they practised bush burning which could adversely affect the environment. However, awareness of environmental laws was generally low. This finding indicates that law enforcement mechanisms for the implementation of environmental laws are weak in Nigeria. Beyond the activities of the environmental protection agencies established by the Nigerian governments, local measures for environmental protection include temporary withdrawal from aquatic environment and sanction of defaulters. The study concludes that with contamination of natural resources coastal livelihoods have become persistently deplorable. Therefore, combined efforts are essential for controlling environmental challenges in coastal communities.

Breeding Ground Profile of Food Fish Species in Damodar River System

Today unwise anthropogenic activity has disturbed the natural ecosystem globally. Civilization on its way to goal hasdestroyed nature as well as natural diversity. Aquatic ecosystem is also facing the same adverse effect as they are usedas waste releasing source. However, anthropogenic activity has drastically damaged the natural habitat of all the livingbeing. Though river water is used for agriculture, fisheries, residential and industrial developments, mining activity,navigation, power generation and variety of other activities including sand digging and disposal of industrial anddomestic wastes, but still, some natural breeding do exists in the nature. Identification of those natural breeding groundand to bring them under proper conservation is a most effective way of natural breed conservation. The river Damodaris the most important watershed in the eastern part of India and is one of the main tributaries of the Ganga. The riverhoused a healthy fish faunal diversity in the recent past but today in spite of drastic deterioration of natural ecosystem,astonishingly no significant difference occurred in faunal composition of the river system.

Ants, Cataglyphis cursor, Use Precisely Directed Rescue Behavior to Free Entrapped Relatives

Although helping behavior is ubiquitous throughout the animal kingdom, actual rescue activity is particularly rare. Nonetheless, here we report the first experimental evidence that ants, Cataglyphis cursor, use precisely directed rescue behavior to free entrapped victims; equally important, they carefully discriminate between individuals in distress, offering aid only to nestmates. Our experiments simulate a natural situation, which we often observed in the field when collecting Catagyphis ants, causing sand to collapse in the process. Using a novel experimental technique that binds victims experimentally, we observed the behavior of separate, randomly chosen groups of 5 C. cursor nestmates under one of six conditions. In five of these conditions, a test stimulus (the “victim”) was ensnared with nylon thread and held partially beneath the sand. The test stimulus was either (1) an individual from the same colony; (2) an individual from a different colony of C cursor; (3) an ant from a different ant species; (4) a common prey item; or, (5) a motionless (chilled) nestmate. In the final condition, the test stimulus (6) consisted of the empty snare apparatus. Our results demonstrate that ants are able to recognize what, exactly, holds their relative in place and direct their behavior to that object, the snare, in particular. They begin by excavating sand, which exposes the nylon snare, transporting sand away from it, and then biting at the snare itself. Snare biting, a behavior never before reported in the literature, demonstrates that rescue behavior is far more sophisticated, exact and complexly organized than the simple forms of helping behavior already known, namely limb pulling and sand digging. That is, limb pulling and sand digging could be released directly by a chemical call for help and thus result from a very simple mechanism. However, it's difficult to see how this same releasing mechanism could guide rescuers to the precise location of the nylon thread, and enable them to target their bites to the thread itself.

Stress of hydraulic engineering on fisheries in the lower reaches of the Yangtze River and compensation

长江下游及河口区鱼类物种丰富,特有性高.能构成渔汛的经济品种均集中在该江段,其可捕的经济鱼类品种及渔获量为全江之首.该水域鱼类区系复杂.是长江物种多样性最为丰富的区域之一.随长江于流上水工建筑的大量建造,江湖被隔绝,洄游通道被阻断,海水的入侵、生境的破碎、水文条件的改变等导致了渔业生态功能的削弱,对下游鱼类可捕量、天然鱼类资源、物种多样性、种质资源产生了严重影响.通过对下游渔业资源特征进行了捕述,结合当前重大水工建筑:水电工程、调水工程、航道工程、大桥工程及沙石开采工程,介绍了长江水工工程的规模与现状,探讨了不同工程对鱼类环境业已显现的影响,以及对渔业生态和资源的破坏作用,剖析水工工程对渔业可能造成的潜在伤害.同时就工程规划的设计理念、渔业生态的补偿措施提出了建议,指出渔业部门应尽的责任和义务,提出了保护下游渔业资源和生态环境急待开展的科学研究任务.;In the Low reaches of Yangtze River and the estuary region, there are rich fish species and high autochthonous species. The economic species that has an obvious fishing season characteristic almost distributes in this area, and the species number of the economic fish and fish catchability ranked first in the whole basin. In recent years the fishery ecological function has been weakened by many factors, such as river-lake disconnection, seawater intrusion, habitat fragmentation and hydrological changes due to the hydraulic engineering, and fish catchability, natural fishery resources, species diversity and idioplasm resources were also influenced seriously. In this paper, the development and status of hydraulic engineering and characteristics of fishery resources in the lower reaches of the Yangtze River have been introduced, basing on some important hydraulic engineering, such as waterpower projects, migration engineering, navigation engineering, bridge construction, and sand digging. Existing and latent impacts of hydraulic engineering on fishery resources and fishery ecological environment have also been discussed. Suggestions on design of hydraulic engineering and compensation methods for fishery ecology have been given. Responsibilities and obligations that the fishery department should take were pointed out. At last the urgent research tasks of protection of fisheries resources and environments in lower reaches of the Yangtze River were put forward.

Effects of rearing conditions on sand digging efficiency in juvenile cuttlefish

The effect of environment on the maturation of sand digging behaviour in cuttlefish was studied. Sand digging behaviour of cuttlefish individually reared on sand was daily observed in their rearing tanks (first study). Other cuttlefish were individually reared from hatching to 2 weeks of life in different conditions (Group A, on a sandy substrate and group B, without sand). At days 0, 3, 6, 9, 12 and 15, cuttlefish from Groups A and B were placed in a novel tank, the bottom of which was covered by sand (second study). The first study shows that more and more cuttlefish sand dig in their rearing tank during the first 6 days of life. The second study shows that, confronted with a novel sand bottom, cuttlefish from Group A show shorter latencies of sand digging and they cover more completely than do cuttlefish from Group B. This indicates that the developmental changes in sand digging appear not totally pre-programmed, but at least partially experience-dependent. Presence of sand in rearing tanks may allow cuttlefish to acquire experience of digging to make this behaviour more efficient.

Interactions of “prepared” behaviors: burrowing and sand digging of rats

Little is known about the potential for laboratory shaping of “prepared” behaviors except that they are resistant to traditional manipulations. This paper shows that two forms of digging by Rattus norvegicus , behaviors that are remarkably uninfluenced by operant reinforcement, are strongly influenced when one experience precedes the other. Rats who burrowed in large boxes of dirt or dug sand from a hopper first showed a clear decrement of performance in the other digging paradigm. Additional experiments suggested that the mutually inhibitory effect is (1) not transitory, (2) probably related to raised thresholds, and (3) counteracted when an effective releaser or facilitator is added to the second digging experience. It may be that interference between the two types of digging is related to their different functions in nature.

A sand-digging apparatus for rats

An apparatus that permits automatic recording of the topography of sand digging was described. Research carried out to evaluate the apparatus indicates that time in sand contact is better correlated with the amount of sand displaced than frequency of contact. Experiment II shows that a sand-and-iron-filing mixture has no suppressive effect on sand digging as compared to normal sand.

Conditions necessary for sand digging in laboratory rats

Continuous availability of a sand blocked tube elicited intense and persistent digging by laboratory rats. Neither training nor prior exposure to the apparatus were necessary for response initiation. Continuous presence of an open pile of sand would not elicit digging. No theoretical explanation is offered.

Limnological studies on some lakes in the Netherlands

SUMMARYMost Dutch lakes are small and shallow, resulting from peat dredging since the late 18th century. However, deep lakes have appeared recently owing to sand digging. Limnological features of one such lake, Wijde Biik (N. Holland), were studied during 1968–70. The lake with an average depth of 11 4 m (maximum depth 31 m) and area of 2·65 × 106m2 is one of the deepest and biggest in the Loosdrecht‐lakes area. The lake is 125 cm below sea level, and underground water‐movements play an important part in the lake's hydrology.The lake exhibits thermal stratification on warm and calm days; since the lake surroundings are open and flat, wind and nocturnal cooling destroy such a stratification. There is continuous circulation from autumn through spring. The O2 saturation (%) in the upper water varies from 70 to 120%. Bottom waters were never anaerobic (lowest values 10% O2 saturation).CI− (2·8m‐equiv.) and HCO−3 (1·9 m‐equiv.) were the dominant anions just as Ca++ (2·77 m‐equiv.) and Na+ (2·5 m‐equiv.) formed the main cations. Chlorides have increased 2·5‐fold in the 40 years as a geochemical consequence of deepening. The surface drainage has minor influence on lake's water chemistry. Part‐P (10–140 μg/I) and PO4‐P (2–40 μg/1) recorded maximum and minimum respectively, and NO3‐N (0·05–1·15 mg/1) its minimum, during Microcystis abundance in August 1968. The SiO2‐Si decreased from February 1969 (400 μg/l) to June 1969 as Diatotna elongatum increased. The Si‐decrease to <30% of the 1932 values is due to removal of Si‐rich clay and silt, due to sand digging.Chlorococcales were the important lake algae. Desmids were poor. Microcystis dominated as a rule from July‐September, achieving from 15 to 31 colonies/ml. Poor light transmission rather than nutrients limits plankton growth as also the primary production in the lake. Copepoda were the dominant zooplankton. Bosmina coregoni recorded between 2 and 44 individuaIs/1 in summer 1968 and was the main cladoceran. The average primary production during summers of 1969 and 1970 was 380 and 497 mg C m−2 day−1 respectively. Light limited production below 1 m—1 % light in 1969 and 10% in 1970 penetrated down to 4 m. About 70% of the production took place in the upper 2 m. Calculation of production according to theoretical models under‐estimated the observed values by 12% because Z0·5Ik lay much above (0·8–2·8 m) the expected value of 3·5 m. It is suggested that in turbid lakes like Wijde Blik in situ incubations should be done at 0·5 m intervals in the upper 2 or 3 m.

Differential extinction of a sand digging response in the rat

Eighty water-deprived rats were trained to dig through 20.42 kg of sand. After reaching a relatively high performance criterion Ss, were divided into eight groups which differed in combinations of deprivation schedule and water placements in the apparatus. Satiated Ss dug at a significantly lower rate than deprived Ss, but within the deprivation treatment groups, Ss with water in the start box dug significantly slower. Extinction behavior was consistent for the different groups over the 15 trials tested, and none of the animals showed complete extinction. Relevant behavioral observations were also noted and discussed.

Sand digging of C-57 mice

The present study explores the sand-digging behavior of a highly inbred strain of mice (C-57) to see if they, like Peromyscus and laboratory rats, will volunteer to dig large amounts of sand in the absence of primary rewards. The effects of training (pacing) are also examined.

The effects of prolactin and testosterone on the parental behaviour of the male stickleback Gasterosteus aculeatus

Injections of mammalian prolactin (lactotrophic hormone LTH) failed to induce fanning behaviour or to intensify either displacement fanning or parental fanning of the male threespine stickleback. Castration greatly reduces or entirely eliminates fanning behaviour in sexually active male sticklebacks. Treatment with methyl testosterone maintains or restores fanning in castrated males. With a series of graded doses of methyl testosterone, the earlier stages of reproductive behaviour (sand digging) appear at the lower dosages while the later elements (fanning) are evident at full intensity only with the higher dosages. All of the evidence indicates that the parental fanning is regulated by the androgenic hormones of the testes. Prolactin probably exerts its physiological action during the pre-sexual migratory period of the reproductive cycle.

Sand digging contingent upon bar pressing in deermice ( Peromyscus)

1. 1. Five stocks of Peromyscus were tested for the quantity of sand they could remove from a tunnel in 24 hours. The stocks were P. maniculatus bairdii (domesticated and first laboratory generation of wild caught), P. maniculatus gracilis, P. leucopus, P. floridanus. 2. 2. P. m. gracilis dug significantly less sand than the other species, which did not differ, except for the first laboratory generation of wild caught P. m. bairdii, which failed to dig. 3. 3. A second experiment testing the reinforcing value of sand digging was performed with P. leucopus. The opportunity to dig sand was contingent upon pressing one of two bars, which provided sand over a period of 24 days. 4. 4. Acquisition of the position discrimination occurred during the first 12 days, but reversal learning did not take place during the second 12 day period. Controls receiving no sand had a significantly lower bar pressing rate than those making the discrimination. 5. 5. The results suggest that phenotypic expression of the genotype in terms of habitat selection and habitat utilization depends to a certain extent upon the reinforcing properties of the environment,