A Review of the Engineering Role of Burrowing Animals: Implication of Chinese Pangolin as an Ecosystem Engineer

Ecosystem engineers are organisms that alter the distribution of resources in the environment by creating,modifying,maintaining and/or destroying the habitat.They can affect the structure and function of the whole ecosystem furthermore.Burrowing engineers are an important group in ecosystem engineers as they play a critical role in soil translocation and habitat creation in various types of environment.However,few researchers have systematically summarized and analyzed the studies of burrowing engineers.We reviewing the existing ecological studies of burrowing engineer about their interaction with habitat through five directions:(1)soil turnover;(2)changing soil physicochemical properties;(3)changing plant community structure;(4)providing limited resources for commensal animals;and/or(5)affecting animal communities.The Chinese pangolin(Manis pentadactyla)is a typical example of burrowing mammals,in part(5),we focus on the interspecific relationships among burrow commensal species of Chinese pangolin.The engineering effects vary with environmental gradient,literature indicates that burrowing engineer play a stronger role in habitat transformation in the tropical and subtropical areas.The most common experiment method is comparative measurements(include different spatial and temporal scale),manipulative experiment is relatively few.We found that most of the engineering effects had positive feedback to the local ecosystem,increased plant abundance and resilience,increased biodiversity and consequently improved ecosystem functioning.With the global background of dramatic climate change and biodiversity loss in recent decades,we recommend future studies should improving knowledge of long-term engineering effects on population scale and landscape scale,exploring ecological cascades through trophic and engineering pathways,to better understand the attribute of the burrowing behavior of engineers to restore ecosystems and habitat creation.The review is presented as an aid to systematically expound the engineering effect of burrowing animals in the ecosystem,and provided new ideas and advice for planning and implementing conservation management.

The hypoxia adaptation of small mammals to plateau and underground burrow conditions

Oxygen is one of the important substances for the survival of most life systems on the earth,and plateau and underground burrow systems are two typical hypoxic environments.Small mammals living in hypoxic environments have evolved different adaptation strategies,which include increased oxygen delivery,metabolic regulation of physiological responses and other physiological responses that change tissue oxygen utilization.Multiomics predictions have also shown that these animals have evolved different adaptations to extreme environments.In particular,vascular endothelial growth factor(VEGF)and erythropoietin(EPO),which have specific functions in the control of O_(2) delivery,have evolved adaptively in small mammals in hypoxic environments.Naked mole-rats and blind mole-rats are typical hypoxic model animals as they have some resistance to cancer.This review primarily summarizes the main living environment of hypoxia tolerant small mammals,as well as the changes of phenotype,physiochemical characteristics and gene expression mode of their long-term living in hypoxia environment.

Burrow Characteristics and Microhabitat Use of the Turpan Wonder Gecko Teratoscincus roborowskii (Squamata, Gekkonidae)

Burrow structural charactersitcs and microhabitat use of the Turpan wonder gecko Teratoscincus roborowskii （Gekkonidae） were studied between April and September of 2013 in the Turpan Eremophytes Botanic Garden, in the Turpan Depression of Western China. Burrow depth, entrance orientation, entrance height and width were observed. We assessed microhabitat selection and noted differences in microhabitat use among males, females, and juveniles. The magnitude of selection was measured using Jacobs＇ index of selectivity. Entrance height and width of the burrows of adults were significantly larger than those of juveniles, but the difference in burrow depth was not significant. The directional orientation of the burrow entrance showed a preference for the north-northeast and south-southeast, which were likely influenced by local prevailing winds and sunlight. Both the adult and juvenile geckos prefer to construct their burrows in sandy soil within a layer of loose soil whose thickness is greater than 30 cm. A majority of the burrows were located within 20 m of the nearest plant. Nearly half （48%） of the entrances of juveniles were located within 5 m of the nearest vegetation, significantly different from those of the adults. Results showed that the Turpan wonder gecko did not utilize microhabitats according to their availability, but rather that it preferred rnicrohabitats which contained dead wood or the caper bush. Our results suggested that burrow characteristics and microhabitat selection were important factors in T. roborowskii adaptation to harsh and arid desert habitats.

Large Tetrapod Burrows from the Permian Naobaogou Formation of the Daqingshan Area, Nei Mongol, China

Two new tetrapod burrow casts from the Naobaogou Formation （Middle or Late Permian） of Nei Mongol,China are described.It marks the first pre-Cenozoic tetrapod burrow from China,and one of the earliest records of tetrapod burrows.Comparison to other Permian and Triassic burrows suggests that these burrows were created by tetrapod slightly smaller than Lystrosaurus.Deduced from the morphology and sizes of two burrows and known tetrapods of the Naobaogou Formation,the burrow should be the production of a therapsid,most likely a dicynodon.These burrows indicate a seasonal climate and this area was semiarid or arid during that time.

Effect of mangrove restoration on crab burrow density in Luoyangjiang Estuary,China

Background： Mangrove restoration seeks to restore or rebuild degraded mangrove systems. The methods of mangrove restoration include ecological projects and restoration-oriented technologies, the latter of which are designed to restore the structure, processes as well as related physical, chemical and biological characteristics of wetlands and to ensure the provision of ecosystem services. As important components of mangrove ecosystem, benthic organisms and crabs play a key role in nutrient cycling. In addition, mangrove restoration, such as vegetation restoration measures, can lead to changes in the benthic faunal communities. This study investigates whether the presence of different mangrove species, age and canopy cover of mangrove communities affect the density of crab burrows. Methods： The Luoyangjiang Estuary, in the southeast of Fujian Province, was selected as our research area. A survey, covering 14 sites, was conducted to investigate the impacts of mangrove restoration on the density of crab burrows in four rehabilitated forests with different stand ages and canopy. Results： It was found that differences in vegetation types had a large impact on crab density and that the density of crab burrows was lower on exposed beaches （non-mangrove） than under mature Kondelio condel, Aegiceros corniculatum and Avicennio morina communities. In general, the amount of leaf litter and debris on mangrove mudfiats was greater than on the beaches as food sources for crabs. Two-factor analysis of variance （ANOVA） shows that changes in mangrove species and age since restoration had different effects on crab burrow density. The effect of canopy cover was highly significant on crab burrow density. Conclusions： The results suggest that in the process of mangrove restoration the combined effects of mangrove stand age, canopy cover and other factors should be taken into account. This study further supports the findings of the future scientific research and practice on mangrove restoration and management measures.

The effect of substrate grain size on burrowing ability and distribution characteristics of Perinereis aibuhitensis

Perinereis aibuhitensis(Grube, 1878) lives in marine sediments of estuary or shoal areas, where substrate has some crucial environmental factors affecting its burrowing and distribution. In order to provide basic data for the habitat selection and suitability evaluations of the artificial aquaculture of P. aibuhitensis, this paper conducted a quantified analysis of its burrowing ability and explored its behavioral preferences in different substrates,including mud(<75 μm), fine sand(125–250 μm), medium sand(250–500 μm), coarse sand(500–2 000 μm), gravel(2 000–4 000 μm) and ceramsite(4 000–8 000 μm). The research results revealed that substrate grain size significantly affected the burrowing time, burrowing rate, burrowing depth and distribution rate(P<0.01).Moreover, P. aibuhitensis demonstrated preferential selections relating to substrate grain sizes, had higher burrowing ability in ceramsite, mud and fine sand compared with other substrates. The strongest burrowing ability and the highest distribution rate were observed in ceramsite. The study indicated that P. aibuhitensis was sensitive to substrate grain size, which also had an impact on its burrowing process and population distribution.In the natural sea, substrates mainly composed of mud and fine sand are fit for aquaculture and stock enhancement. Based on behavioral preferences and ecological rehabilitation function of P. aibuhitensis, this paper proposes a symbiotic system of marine animals and halophytes, and constructs an ecosystem model of"Marine fish-Halophytes-Perinereis aibuhitensis" with P. aibuhitensis as the link.

The Habitats, Burrowing Behavior, Physiology Adaptation and Life Cycle of Spadefoot Toads (<i>Pelobates syriacus, Boettge</i>r, 1869) at the Southern Limit of Its Distribution in Israel

The present study describes the habitats, life cycle, larvae growth, burrowing behavior and terrestrial adaptation of Spadefoot toads in Israel based on observations and data collected during more than 30 years in northern Israel. The distribution area in Israel is from the north in the Upper Galilee and Golan Heights (annual rainfall range of 500 - 1000 mm) to the southern coastal plain (annual rainfall of about 250 mm). Among the 51 different breeding places of amphibians, only ponds where water was available for a few months were used by Spadefoot toads and metamorphosed populations were found around these ponds. The larvae underwent metamorphosis during the summer and autumn in northern Israel, and during the spring in central and southern Israel. A negative correlation exists between the percentage of toads burrowing and soil moisture levels, with greater burrowing behavior occurring under dry conditions. The plasma concentration increased during burrowing by electrolytes and urea accumulations. The burrowing behavior helped Spadefoot toads survive in this area at the southern border of its distribution.

Impact of Human Disturbance on Fiddler Crab (<i>Uca tangeri</i>) Burrow Morphology, Distribution and Chemistry at Eagle Island, Niger Delta, Nigeria

Fiddler crabs are described as ecosystem engineers because of their burrow constructing ability. It was hypothesized that human activity will impact crab burrows. The study area was delineated into lowly, medium and highly impacted plots. Crab holes were randomly counted and their width, length and surface area estimated. Burrow soils were collected and analyzed for Cadmium (Cd), Lead (Pb) and Zinc (Zn) using spectrophotometric method (HACH DR 890 colorimeter). The result indicates that burrow width was significantly different between impacted plots (P < 0.05). Lowly impacted plot had the largest width while highly impacted plot had the smallest width. In contrast, there was no significant difference in burrow length (P > 0.05), but highly impacted plot has the longest length while lowly impacted plot has the shortest length. Again, the surface area of crab burrow varies significantly (P < 0.05), and lowly impacted plot had the largest area (507.95 ± 61.84 cm2) followed by medium (390.30 ± 57.65 cm2) and high (265.16 ± 30.85 cm2) impacted plots. Similarly, lowly impacted area has more number of burrows (n = 55) followed by medium (n = 30) and highly (n = 23) impacted plots. Highly impacted plot had the highest Cd and Pb concentration whereas lowly impacted plot had the highest Zn concentration. This implies that burrow morphology and chemistry exemplify the level of anthropogenic impact.

Do Larger and Older Individuals Occupy Better Areas in the Colony of Qinghai Toad-headed Agamas?

Group living reduces the chances of predation.This is also true for burrowing animals,which use burrows as refuges to escape predators.Living in the center of a colony is the safest because it offers access to the greatest number of burrows;however,it is stressful due to frequent aggressive interactions there.We predicted that larger and older animals should occupy areas of a colony with a higher density of burrows than smaller and younger ones.To test this prediction,we observed individually marked Qinghai toad-headed agamas(Phynocephalus vlangalii)from a single colony late in the breeding season when females were gravid.Density of burrows was the highest and distance between them the shortest in the center of the colony.Aggressive encounters were more frequent in the central part of the colony than on its periphery.We found a negative correlation between body size and distance to the center of the colony for females,but not for males.There was no such correlation between age of individuals and distance to the center of the colony.Females in this species likely compete with other females and males for central burrows in the colony even after mating season finishes.We suggest that gravid females likely compete for the dense burrows within the central part of the colony mainly due to their relatively lower sprint speed and higher probability of being caught by a predator if they are not refuged in a burrow.

A Glimpse into the Natural History of Leiolepis rubritaeniata Mertens,1961(Squamata:Leiolepididae)

During the months of April through July 2020 we studied aspects of the natural history of Leiolepis rubritaeniata,a species of butterfly lizard that occurs on the Khorat Plateau in Thailand and adjacent regions of Laos and Cambodia as well as in south-central Vietnam.We present data on population size and structure,as well as location,size,compass orientation,and structure of the lizard’s burrows.Also,we present climatic data(ambient air temperature and precipitation)at the study site for the duration of our field work as well as temperature data for the complete year 2021.Furthermore,we provide data on egg laying,incubation conditions and characteristics of the hatchlings.Finally,we present an easy to use and reliable non-invasive method for the long-term recognition of individual butterfly lizards based on their unique dorsal patterning.Butterfly lizards are utilized as a food source for the local human population.So far,there are no farming projects in Thailand involving this species and all individuals are collected from the wild populations.No data are available on the population dynamics of L.rubritaeniata but it can be assumed that habitat destruction due to land use change as well as its utilization for human consumption have negative effects on the long-term survival of the local populations of this lizard species.The baseline data presented here are essential for any meaningful conservation strategy for these lizards.

Alpine grassland degradation intensifies the burrowing behavior of small mammals:evidence for a negative feedback loop

Globally,grassland degradation is an acute ecological problem.In alpine grassland on the Tibetan Plateau,increased densities of various small mammals in degraded grassland are assumed to intensify the degradation process and these mammals are subject to lethal control.However,whether the negative impact of small mammals is solely a result of population size or also a result of activity and behavior has not been tested.In this study,we use plateau pika as a model to compare population size,core area of colony,and the number of burrow entrances and latrines between lightly and severely degraded grassland.We test whether the alleged contribution of pika to grassland degradation is a result of increased population size or increased burrowing activities of individuals in response to lower food abundance.We found that grassland degradation resulted in lower plant species richness,plant height,and biomass.Furthermore,the overall population size of pika was not significantly affected by location in lightly and severely degraded grassland.However,pika core areas in severely grassland degradation were significantly larger and had significantly higher densities of burrows and latrines.Our study provides convincing evidence that habitat-induced changes in the behavior of small,burrowing mammals,such as pika,can exacerbate grassland degradation.This finding has significant implications for managing small mammals and restoring degraded grassland ecosystems.

高原鼠兔洞系特征及功能研究

通过在甘南玛曲900个洞口的实地调查,对高原鼠兔的洞系特征(洞口数量、位置、朝向、格局,洞道结构等)进行了系统研究。结果表明,高原鼠兔不同洞口朝向间的洞口数存在显著差异,其中全阴、半阴、全阳间的差异极显著;洞口直径与洞口朝向无相关性;洞口斜度≤55°的洞口主要集中在SW、SE和S 3个方向,占洞口总数的48.6%,洞口斜度>55°的洞口主要集中在NW、NE和N 3个方向,占洞口总数的52.1%;S向和偏S向的洞口温度显著高于N向和偏N向的洞口,W向和偏W向洞口温度普遍高于E向和偏E向洞口,前者最高温差可达13.2℃,后者最高温差为6.0℃。由上述可见,高原鼠兔的洞系建筑特点是对高原环境的一种适应性选择,除了常规意义上的栖居和避险等基本功能而外,还兼顾了洞内温度、对流和抵御寒风的利弊权衡。

棕色田鼠洞群内社会组织

每月选取农田样方 ,用洞道内置夹及挖捕法对棕色田鼠洞群内的群体结构进行调查发现 ,棕色田鼠在不同的季节 ,洞群内个体组成不同。在 4月和 10月 ,同洞群内成年雄性和雌性的数量较多 ,往往有两个以上的雌性个体参与繁殖 ,而且亚成体和幼体的数量也较多 ;而6月至 9月 ,棕色田鼠多呈雌雄一一配对 ,有些洞群内也有幼体和亚成体 ,雌雄共巢 ,而呈现单配制特征。所以其社会组织呈现群居家庭、双亲家庭和单亲家庭 3种类型。 4月和 10月群居家庭最多 ( 60 % ,61 53% ) ,6月和 9月双亲家庭较多 ( 80 % ,75% ) ,双亲家庭所占比例和密度呈负相关 ,而群居家庭所占比例和密度呈正相关。在不同的季节洞口系数不同 ,洞口系数和密度呈正相关。

高原鼠兔种群恢复过程中的洞穴分布动态

高原鼠兔洞穴系统的恢复是其种群恢复的关键指标之一,洞穴分布的变化可以反映种群的动态。本研究于2014-2016年在青海省祁连县对2.79 hm^2高寒草甸内高原鼠兔种群密度、洞穴密度和洞穴的相对位置进行跟踪观测。其中包括6个50 m×50 m的灭鼠堵洞处理、6个30 m×30 m的灭鼠处理和3个50 m×50 m的对照处理。分别采用平均最近邻指数和平均拥挤度指数分析洞穴系统中有效洞、弃洞、粪坑和嬉戏坑的分布模式及洞系表现面积,并对各参数进行描述性和相关性分析。结果显示:高原鼠兔种群密度恢复过程中(1)有效洞的空间格局由随机向离散分布转变,弃洞由随机向聚集分布转变,粪坑和嬉戏坑无明显变化趋势;有效洞和弃洞分布格局的恢复都朝向灭鼠前状态,但恢复的都不充分;(2)有效洞最近邻指数与其自身密度正相关;弃洞最近邻指数与其自身密度负相关;粪坑、嬉戏坑最近邻指数与其自身密度无显著相关性;其中,仅粪坑的分布最近邻指数与高原鼠兔种群密度呈显著负相关;(3)有效洞与粪坑、嬉戏坑表现面积的变化情况较为一致,与弃洞呈互补态势;洞系表现面积的变异性远小于洞穴密度。结果说明:(1)高原鼠兔洞穴分布格局和洞穴密度的恢复具有滞后性;(2)有效洞、弃洞的分布格局主要受洞穴密度的影响;(3)高原鼠兔种群的恢复过程中对洞系面积的需求优先于洞口数量。

类BAN逻辑的缺陷分析

类BAN逻辑是密码协议分析和设计的主要工具,文章在分析了类BAN逻辑之后,指出了这些逻辑的缺陷,并对类BAN逻辑的缺陷进行分类,最后指出进一步发展类BAN逻辑应解决的问题。

The Relationship between Shell Morphology and Crevice Size Affecting Retreat Selection of the Keeled Box Turtle(Cuora mouhotii)

Rock crevices are important retreat sites for many reptiles.Unlike lizards and snakes,crevicedwelling turtles have rigid shells which severely limit the size and shape of crevices they are able to use.Few studies have addressed the relationship between turtle's shell morphology,behavior,and crevice size.Here,we investigate the relationship between morphology and crevice size selection in the Keeled box turtle(Cuora mouhotii).We radio tracked turtles in the field to document crevice dimensions and turtle behavior associated with crevices,and we conducted a controlled experiment in the lab to understand how a turtle's morphology influences its decision to select crevices with different dimensions.Both laboratory and field experiments demonstrate that turtles select deep and moderately wide crevices that are low enough to barely accommodate the carapace.Crevices used by turtles tend to be about 2 times as wide,1.2 times as high,and 3 times longer than the turtle's shell.Moreover,turtles tended to prefer crevices with horizontal openings in the field and position themselves head first in the crevice.We conclude that morphology,especially carapace height,influences the Keeled box turtles' decision to select specific sizes of crevice.We argue that the tendency for turtles to select crevices that come into contact with their carapace contributes to successful defense against predators,as it would be more difficult for a predator to remove a turtle when the crevice is nearly touching the turtles shell.

Reproductive ecology of the mudskipper Boleophthalmus pectinirostris

The reproductive ecology of the mudskipper Boleophthalmus pectinirostris was investigated during the spawning season in the Funing Bay, Fujian, China. The fish burrows were basically Y-shaped and had two openings onto the mudflats. Part of the intersection at the center of the burrow was dilated to form a ＂spawning chamber＂. The dissolved oxygen concentrations （ 0.40 ～ 0.65 mg/dm^3） of water 15 cm deep inside the burrows were much lower than those （5.96 ～ 6.19 mg/dm^3） of intertidal pool water. Water temperatures inside the burrows were much lower than those of intertidal pools. Field investigations indicated that eggs were laid on the inner wall and ceiling of the spawning chamber by means of filamentous attachments, and a male stayed inside the burrows to guard it. Field investigations also suggested that fish of both sexes constructed mud burrows by themselves but that the spawning chamber was made only in the male burrow. The male attracted a female to his burrow for mating and spawning. There was no water in the spawning chamber, and thus the eggs were exposed to the air in the chamber. Changes in spawning readiness and gunadosomatic index indicated that synchronization of spawning was related to the semi-lunar periodicity, and this is the first report of this relationship in the mudskippers.

Parasitism and pathogenicity of Radopholus similis to Ipomoea aquatica, Basella rubra and Cucurbita moschata and genetic diversity of different populations

Ten populations of Radopholus similis from different ornamental hosts were tested for their parasitism and pathogenicity to water spinach （Ipomoea aquatic）, malabar spinach （Basella rubra）, and squash （Cucurbita moschata） in pots. The re- sults showed all three plants were new hosts of R. similis. Growth parameters of plants inoculated with nematodes were significantly lower than those of healthy control plants. All R. similis populations were pathogenic to the three plants, but pathogenicity differed among populations from different hosts. The same R. similis populations also showed different pathogenic effects in the three different plants. RadN5 population from Anthurium andraeanum had the highest pathoge- nicity to the three studied plants. RadN1 from A. andraeanum had the lowest pathogenicity to squash and RadN7 from Chrysalidocarpus lutesens had the lowest pathogenicity to water spinach and malabar spinach. R. similis is usually associated with root tissues, but here we report that it could be found to move and feed in the stem bases of all three studied plants. Sequence and phylogenetic analyses of DNA markers of the 18S rRNA, 28S rRNA, ITS rRNA, and mitochondrial DNA gene sequences of ten R. similis populations revealed significant genetic diversity. RadN5 and RadN6 populations from anthurium showed a close genetic relationship and could be distinguished from other populations by PCR-RFLP. At the same time, RadN5 and RadN6 populations were the most pathogenic to three studied plants. These results confirm the existence of large biological variability and molecular diversity among R. similis populations from the same or different hosts, and these characteristics are related to pathogenic variability.

怀来县长城系团山子组内发现潜穴

本文详细描述了在河北省怀来县境内长城系团山子组猪肝色白云岩内发现的潜穴和生物扰动构造,潜穴个体较小,最大者长5～7mm,d=2～3.5mm,最小者长2mm,d=0.08mm,形态多样,为短直管状、锥状、罐状、长管状。该发现为动物出现时间的大大超前(时限约在1700～1757Ma之间)提供了确凿证据。

Effects of commercially produced almond by-products on chemotherapy-induced mucositis in rats

AIM To determine if almond extracts reduce the severity of chemotherapy-induced mucositis as determined through biochemical,histological and behavioural markers.METHODS Intestinal mucositis is a debilitating condition characterized by inflammation and ulceration of the gastrointestinal mucosa experienced by cancer patients undergoing chemotherapy.Certain bioactive plant products have shown promise in accelerating mucosal repair and alleviating clinical symptoms.This study evaluated almond extracts for their potential to reduce the severity of chemotherapy-induced mucositis in Dark Agouti rats.Female Dark Agouti rats were gavaged(days 3-11) with either PBS,almond hull or almond blanched water extract at two doses,and were injected intraperitoneally with 5-fluorouracil(5-FU-150 mg/kg) or saline on day 9 to induce mucositis.Burrowing behavior,histological parameters and myeloperoxidase activity were assessed.RESULTS Bodyweight was significantly reduced in rats that received 5-FU compared to saline-treated controls(P < 0.05).Rats administered 5-FU significantly increased jejunal and ileal MPO levels(1048%; P < 0.001 and 409%; P < 0.001),compared to healthy controls.Almond hull extract caused a pro-inflammatory response in rats with mucositis as evidenced by increased myeloperoxidase activity in the jejunum when compared to 5-FU alone(rise 50%,1088 ± 96 U/g vs 723 ± 135 U/g,P = 0.02).Other extractrelated effects on inflammatory activity were minimal.5-FU significantly increased histological severity score compared to healthy controls confirming the presence of mucositis(median of 9.75 vs 0; P < 0.001).The extracts had no ameliorating effect on histological severity score in the jejunum or ileum.Burrowing behavior was significantly reduced in all chemotherapy-treated groups(P = 0.001).The extracts failed to normalize burrowing activity to baseline levels.CONCLUSION Almond extracts at these dosages offer little beneficial effect on mucositis severity.Burrowing provides a novel measure of affective state in studies of chemotherapyinduced mucositis.