Crocodile and the Plover Bird – SmallScience
The Crocodile Bird: A Novel Mass Market Paperback – October 10, by .. A symbiotic relationship in nature is one where two creatures provide mutually. Crocodiles are a close living relatives of birds, but compared to their feathered cousins, they are stuck in the past, scientists claim. The reptiles. A symbiotic relationship has been observed only between Nile Crocodiles and Egyptian plover birds Nile Crocodile and Egyptian Plover by.
So, the Plover bird gets her food and the crocodile gets his mouth cleaned. In this way, both are able to help each other! Let us get to know a little bit more about these creatures: A crocodile is a carnivore which means it eats all kinds of animals that live in the water and even cattle. They have strong jaws. They do not chew their food, just swallow the entire prey into their stomach where it is broken down.
It is while swallowing that the bits of flesh get stuck in their teeth. You will find them swimming just like this beneath the surface of water with their eyes and nostrils just above. Often you will find them lazing around in the sun with their mouth wide open.
They have powerful jaw muscles and can keep their mouth open for a long time. Let us look at the Plover Bird closely. The Lake extends from the dam itself in the north to the Cataract at Dal, Sudan in the south. The purpose of constructing the Aswan High Dam AHD was primarily to benefit the downstream side by controlling annual floods, provide irrigation to about two million feddans and generate electricity. Indirectly, however, the upstream side has also benefited because of the formation of the lake, which has created great possibilities for fisheries, navigation, agricultural production and even tourism.
The region from Aswan to Adindan, which was previously an undeveloped desert, is already developed by controlled use of water from the reservoir Bishi The area of the reservoir at m level is about km2 of which Lake Nasser occupies about km2. The mean depth of Lake Nasser at m level is The mean width of the Lake at m level is 8. Morphometric data of Lake Nasser at water levels of and m are presented in Tables 1 and 2.
The side areas lie between and m a. The mean depth of this central part is gradually increasing from 10 m at the southern end to 70 m in the north. The bulk of the water masses coming from the south are passing through the central part, which forms about half of the total volume of the Lake Entz and Latif and Entz The flood, which arrives at Aswan from Khartoum within one month before the High Dam was built, covers now the same distance in not less than 5 months but sometimes probably more than 12 months depending on Lake level and the strength of the flood.
A delicate plant cover has developed during the last few decades along the shores of Lake Nasser, on the hand, the use of statistical methods ordination and classification techniques emphasize the groups of species and their distribution along the shoreline of Lake Nasser affected by the prevailing environmental conditions that in the same time affected on the lake Nasser ecosystem.
Mainly the distribution of these species is robustly related to the moisture gradient as well as Lake Nasser water level. Each cluster is named after the dominant species and identified according to its associated species as described below. Hyoscyamus muticus - Tamarix nilotica - and Glinus lotoides. Tamarix nilotica - Glinus lotoides - Cynodon dactylon - Fimbristylis bis-umbellata. Tamarix nilotica - Phragmites australis and Rumex dentatus, and Heliotropium supinum.
Tamarix nilotica - Eragrostis aegyptiaca, Senecio aegyptius, Fimbristylis bisumbellata, and Cyperus laevigatus. Based on the water supply and moisture content which controlling the vegetation distribution along the shoreline.
CA analysis of the species in relation to the moisture content obviously indicates the arrangement of the species along the moisture gradient. AHC analysis separates the groups of species in relation to the moisture gradient which is recognizable in nature. A sequence in the arrangement of the groups of the species indicates the altitudinal zonation of the vegetation. Starting from lower to upper area or from lower slope to higher we can classily the vegetation structure into the following groups based on the soil moisture.
The first group of species and that is characterized the stands that characterized by wet conditions Amaranthus lividus, Crypsis schoenoides and Echiurn rauwolfii, Cynodon dactylon. The second group comprises the mesophytic species Hyoscyamus muticus, Glinus lotoides, Amaranthus sp and Heliotropium supinum associated with the mesic these area that having or characterized by moderate or a well-balanced supply of moisture conditions on the moisture gradient.
The third group Eragrostis aegyptiaca, Senecio aegyptius, Fimbristylis bisumbellata, and Cyperus laevigatus is distributed along the moisture gradient from little mesic to mesic-dry conditions this come in harmony with Springuel et al.
The fourth group Tamarix nilotica, Phragmites australis and Rumex dentatus occupies the dry end on the moisture gradient of Lake Nasser shoreline. These species typically grow on the upper part of the shores, subjected to epigrammatic inundations occurring less frequently than once a year on the other hand, these species looks like border along the shoreline and help Nile crocodiles for nesting and may they used as shelters and they moderate some time the nesting temperature or say they protect nests form the sun.
Finally the desert perennials Salsola imbricata and Pulicaria crispa have a special position out of the recognized moisture gradient. They are native plants in the desert around the Lake and their growth seems to depend on the seed bank rather than on other factors. Along the shores of the lake both plants are present only in isolated locations and do not form a continuous zone.
We conclude that the ordination and classification analyses used in the present study elucidate that the water regime of the Lake is the main factor controlling the growth of the plants and zonation of shoreline vegetation on the other hand the soil parameters have little effect of the spatial variation of vegetation and geographical gradient is less marked as reported by Springuel et al. Vegetation cover around the nest was analyzed as the vegetation which occurred around the nest site.
The vegetation character along the lake Nasser shoreline or the lake banks, are fairly uniform and are not composed of a large diversity of plants.
Vegetation also provides shade for the female crocodile that has to regulate her body temperature while guarding the nest against predators. Pooley reported that that soil temperatures in direct sunlight became unbearably high, thus shade becomes important for the survival of the female crocodile. Nevertheless, too much shade over the nesting site may alter the incubation temperature which will affect sex ratios in the nest, on the other hand at sites that the vegetation rare to occur and no shade, crocodile female, depend on, to wet her body then quickly go toward the nest and wet the sand, such that operation repeated more than time along the day, this come based on the author investigation and felid work in the lake.
Also based up on our investigation the shape and the deep of the nests whole depend up on the soil substrata, which according to our survey where classified on sand, sandy rocky, sandy muddy or with alluvial deposits, and gravelly alluvial deposits, this point need more research in the future In chapter 4: On the other hand, the spotlight counts are innately inaccurate due to the visibility biases, and observers during the survey routes do not see all of the crocodiles present during a survey.
On the other hand, this method is the most frequently working technique to estimate crocodilian population trends as reported by Bayliss et al.
On the other hand, the probability of detection of crocodiles in lake Nasser influenced by several factors include the type and structure of vegetation along the shoreline of lake Nasser between the observer and the crocodile, khors width in lake Nasser, frequency of bends position of the crocodile — submerged, on land, the orientation of the crocodile, and the wariness of the crocodile. As well as the shoreline type sandy, rocky or whatever. All these factor influencing Nile crocodile estimation, and also we not forget the weather condition and waves level.
Large crocodile tend to be more wary than smaller animals as reported by Ron et al. Over a significant period of time, from October - August The spotlight counts of all encounters with crocodiles in the lake Nasser resulted in a reliable population structure and size class distribution pattern. During the last 10 years ago, three surveys have been conducted for crocodiles in Lake Nasser. As reported by Ibrahim the first was conducted by the Lake Nasser Authority over 3 trips during February and March reaching no further than 20km of the High Dam and they cover some areas of Khor El Ramla.
Generally the above three surveys were conducted exclusively during the day and were created with technical errors. Generally, although these surveys provide little in the way of precious quantitative data, they do provide insights regarding the distribution of Nile crocodiles and perceptions of threats to the Lake Nasser fishing community. The low density location have a resembles reasons generally we will discuss the suitability of habitat and habitat disturbance for Nile crocodile in a separate chapter.
But mainly the main reasons for the low percentages of crocodiles that over than 4 m. The size frequency distributions of Nile crocodile populations exhibit a more or less inverse- J- shaped or positively skewed size frequency distribution, which may represent rapidly growing population with high reproductive capacity.
In these populations, the younger individuals are preponderant than older ones, which is an indication of strength and success of the species, it is mostly due to victorious growing and survival of individuals Salem According to the variation of Lake Nasser shoreline length by the water fluctuation, of a total Nile crocodile were observed along our survey of about It was noted that a considerable variation in the total abundance and in the in counter rate in between 42 location see above tables.
According to the area estimated and counted or determined on using supervised classification and 3D modeling of the suitability of habitat, there are of about to km of Lake Nasser shoreline not suitable habitat for Nile crocodile at low water level, this will be discussed in chapter of habitat suitability, but mainly this will reduce the estimate of Nile crocodile by about According to table11 the mean number estimated of crocodile at the given water level Based on our investigation the most correctly mean estimation will be most of our work done around it, I mean the given water level Because large crocodilians tend to be more wary than the smaller size classes and often submerge when approached Webb and Messel, ; Ron et al.
Spotlight counts therefore represent an index of the total population and without an idea of how many animals there are in the system, there is no way to check on the relationship between spotlight counts and total population size Woodward and Moore, However, in combination with population estimates, correction factors can be applied to spotlight count data to improve the accuracy thereof.
Nevertheless, for trend analysis without the knowledge of population size, the assumption is made that the relationship between total population size and spotlight count density remains constant Woodward and Moore, Now, the following what the newspapers published on the Nile crocodile in EgyptSome comments upon what has been written in the Egyptian newspaper about the Nile crocodile in the recent year, starting by what written in Al-Ahram news paper which is one of the famous new paper in Egypt in September 05, Published an article titled "A farm to crocodiles in Egypt, in Lake Nasser" The first farm for breeding crocodiles will be erected in Egypt, in Lake Nasser which will be auspice by the touristic wildlife parks association on an area of acres on the western shores of Lake Nasser located 15 km away from Aswan-Abu Simbel road.
Additionally the project will comprise an open zoo of the endemic species of animals, a Nubian village, golf tracks and gardens. The proof is the increasing fishery harvesting in the lakes in which crocodiles were protected. Since then, Lake Nasser and the Nile crocodile, fishermen and the government in the ongoing conflict and the largest examples of this was published in the newspapers the following,Al-Ahram news paper in Feb.
The figure next to this article summarises this. In order for such a partnership to be successful a number of conditions should be discussed and agreed.
Partnerships for sustainability: let’s learn from the plover bird and the crocodile
I believe that both parties should have shared values. Moreover there must be agreement on a practical level too. What are the actual objectivesof the partnership? The interviews learned us that the parties involved have to develop mutual trust which helps to accept the other and allows them the freedom for their unique contribution. Despite common values and objectives, there will always be differences between the two parties, leaving them to struggle within the partnership and putting pressure on mutual acceptance.
The learning capacity of both partners builds the foundations for reflection a much-underestimated quality, especially in times of pressure and accordingly the adjustment and recalibration of objectives. How do we adjust so that each party can regain its strength and take the next steps? The partnership is proof of a relationship established by two very different enterprises.
Together they experiment, develop, learn, fail and still go on.Kenya: Tourists fascinated by fisherman's relationship with crocs
To me, such partnerships go beyond a transactional relationship that might spring up between a large company and an SEE. Is that relationship any different to that of Verkade or Always?
After all, the supermarket is a sales channel for those companies too. What do you think? Is that another research question?
Crocodilia - Wikipedia
Ideally, a partnership between an SEE and a large company is a symbiotic relationship. A wonderful metaphor, in my view, is the plover bird and the crocodile: They both benefit from the relationship: That balance with mutual benefits is a great ambition in a commercial sense too.
In reality, the balance can be lost if one of the parties undermines it. In such cases, a cowboy lassoing a rodeo calf and clamping down on its back springs to mind, rather than the crocodile and the plover bird.