scholarly journals Drivers of nest survival rate in a southern Tunisian population of Laughing Doves (Spilopelia senegalensis)

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jihen Boukhriss ◽  
Slaheddine Selmi

Abstract Background Investigating the ecological factors and processes shaping nest survival is of great importance for assessing the breeding success of bird populations and understanding their spatio-temporal dynamics. Here, this question is addressed for the Laughing Dove (Spilopelia senegalensis), an expanding Afro-tropical bird in the Tunisian oasis habitat. Methods This study took place in Kettana oasis, in south-eastern Tunisia. Natural Laughing Dove nests were searched for and monitored by means of regular visits, from the discovery date until the end of the breeding attempt (i.e. fledging or failure). Data were then used to investigate the relevance of laying date, nest age (days after clutch initiation), nest height and vegetation structure in the close nest tree environment as predictors of daily nest survival rate, using logistic-exposure models that accounted for heterogeneity in monitoring period among the studied nests. Models including different combinations of covariates were ranked according to their AICc scores, and the model-averaging technique was used for the assessment of the effects of covariates on daily nest survival rate. Results Vegetation structure in the close nest tree environment and nest age provided important predictors of daily nest survival rate, whereas neither nest height nor laying date showed significant effects. Daily nest survival rate was negatively associated with the presence of date palm trees in the close nest tree environment, but it was positively related to nest age. Daily nest survival rate was higher during the post-hatching stage than during the pre-hatching stage. Conclusions Nests placed on fruit trees close to clumps of palm trees suffered higher predation risks compared to those placed on fruit trees situated far from palm trees. This is probably because palm tree clumps provided refuges for nest predators, notably the Black Rat (Rattus rattus) which has been reported to be the main nest predator in the oasis habitat. The predatory activity of this rodent seemed more directed against eggs than nestlings, which may explain the observed increase in daily survival rate with nest age.

Author(s):  
Ahmad Salah Edeen Nassef ◽  
Kalifa Hamed AlMuqbali ◽  
Sheikha Mahmood Al Naqabi

This paper was studying the effects of palm tree wastes on the behavior of the concrete to reduce cement content in the concrete to ensure a sustainable environment. Both fibers of palm tree and the ash of palm tree leaves are used in this study considering different percentages of palm tree wastes, which are replaced the cement, to investigate both of workability and strength of the concrete. Also, the combination of palm tree leaves ash and fibers of palm trees is investigated. The slump and compression tests are carried out to evaluate both workability and concrete strength. The palm fibers were reducing the workability of concrete at both of different percentage of replacement and different fiber lengths. The slump is reduced by 26.667% at 2 cm fibers length and it is completely lost at 5 cm length fibers at the same percentage of replacement of 5% of the cement content. The palm fibers were weakening concrete compressive strength at different percentages and different fiber lengths. Palm leaves ash was enhancing concrete workability and concrete compressive strength.


2021 ◽  
Vol 9 (1) ◽  
pp. 32-35
Author(s):  
Lal awmpuia ◽  
◽  
H. Lalruatsanga ◽  

A survey of plant species inhabiting oil palm trees was conducted in Zawlpui area of Serchhip district, Mizoram. The study area is a tropical potent agriculture zone, wherein small-scale business of Elaeis guineensis plantation is carried out by several farmers mainly within the gentle sloppy terrain. Oil palm with a rough bark harbors immense inhabitation by a variety plants, that rooted mostly on the debris at leaf base. Species diversity on the plant stem supposedly encourage insects and termites to establish herewith, thus causing harming to the tree. The sample stands within 400 m–800 m altitude were picked randomly. A total of 50 palm tree were accounted and all associated plants on the stem above 30 cm from the ground are all recorded. Species that cannot be identified on the site were pressed and observed at Botany Research lab, Pachhunga University College. The survey documented 38 vascular plant species which include 4 epiphytes and 1 non-vascular species of lichen, 1 bryophyte and 4 fungal species at that time. Invasive Peperomia pellucida and epiphytic pteridophytes Nephrolepis biserrata was found in most of the stand sample; however, Peperomia population decreases with the increasing elevation. Dynamics of inhabitant species diversity also correlate to location of tree. The study also established that diversity of inhabiting species was comparatively high on parts of the stem facing sunlight.


2021 ◽  
Vol 6 (2) ◽  
pp. 37
Author(s):  
Liska Simamora ◽  
Damara Dinda Nirmalasari Zebua ◽  
Yoga Aji Handoko ◽  
Nugraheni Widyawati

The demand for palm sugar is increasing since people prefer natural ingredients. Natural and organic food ingredients have the reputation of being healthier and safer than synthetic ingredients. This study will discuss one particular ingredient namely palm sugar which is known as a natural sweetener. Developed countries have started to import palm sugar as a natural sweetener from developing countries. The production of palm sugar in developing countries has an important benefit in the craftsman household economy. However, current production of palm sugar does not meet the increasing demand, which is caused mainly by the lack of farmers, palm sugar craftsmen’s inadequate knowledge of palm sugar production, and poor incorporation of technology both in the cultivation of palm tree and the production process of palm sugar. This literature review study aims to understand the continuity of palm sugar production within the following framework which consists of four steps: (1) identifying current situation, (2) identifying the problems, (3) presenting the resolution, (4) proposing programs and strategies. Based on this framework a few programs and strategies are generated to maintain the continuity of palm sugar production, they are: (1) Palm trees domestication, (2) research and development center for Indonesian palm sugar, and (3) ensuring a good collaboration among the stake holders involved.


2016 ◽  
Vol 7 (2) ◽  
pp. 292-303 ◽  
Author(s):  
John Snyder ◽  
Xiaoming Gao ◽  
John H. Schulz ◽  
Joshua J. Millspaugh

Abstract We reconstructed a historical mourning dove Zenaida macroura nesting dataset to estimate nest survival and investigate the effect of covariates by using a Bayesian hierarchical model. During 1979–1980, 106 study areas, across 27 states, were established to conduct weekly nest searches during February–October. We used roughly 11,000 data sheets to reconstruct the dataset containing 7,139 nests compared to 6,950 nests in the original study. Original and reconstructed nest survival estimates showed little difference by using the original analysis methodology, that is, the Mayfield method. Thus, we assumed we closely replicated the original dataset; distributions of nests found, birds hatched, and birds fledged also showed similar trends. After confirming the validity of the reconstructed dataset, we evaluated 10 different models by using a Bayesian hierarchical modeling approach; the final model contained variables for nest age or stage, nest height, region, but not habitat. The year 1980 had a higher probability of nest survival compared to 1979, and nest survival increased with nest height. The nest encounter probability increased at days 4 and 11 of the nesting cycle, providing some insight into the convenience sampling used in the original study. Our reanalysis with the use of covariates confirms previous hypotheses that mourning doves are habitat generalists, but it adds new information showing lower nest survival during nest initiation and egg laying and a decline when fledglings would be 4 or 5 d old. Regional differences in mourning dove nest survival confirm existing hypotheses about northern states demonstrating greater nest success compared to southern states where differences may reflect trade-offs associated with northern latitudes, weather differences, or food availability.


2019 ◽  
Vol 12 (1) ◽  
pp. 9 ◽  
Author(s):  
Ximena Tagle Casapia ◽  
Lourdes Falen ◽  
Harm Bartholomeus ◽  
Rodolfo Cárdenas ◽  
Gerardo Flores ◽  
...  

Sustainable management of non-timber forest products such as palm fruits is crucial for the long-term conservation of intact forest. A major limitation to expanding sustainable management of palms has been the need for precise information about the resources at scales of tens to hundreds of hectares, while typical ground-based surveys only sample small areas. In recent years, small unmanned aerial vehicles (UAVs) have become an important tool for mapping forest areas as they are cheap and easy to transport, and they provide high spatial resolution imagery of remote areas. We developed an object-based classification workflow for RGB UAV imagery which aims to identify and delineate palm tree crowns in the tropical rainforest by combining image processing and GIS functionalities using color and textural information in an integrative way to show one of the potential uses of UAVs in tropical forests. Ten permanent forest plots with 1170 reference palm trees were assessed from October to December 2017. The results indicate that palm tree crowns could be clearly identified and, in some cases, quantified following the workflow. The best results were obtained using the random forest classifier with an 85% overall accuracy and 0.82 kappa index.


The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 377-388 ◽  
Author(s):  
Scott Wilson ◽  
Kathy Martin ◽  
Susan J. Hannon

Abstract Nest predation is the most important factor limiting reproductive success of Willow Ptarmigan (Lagopus lagopus), as it is for many bird species. Using program MARK, we examined patterns of daily nest survival in two widely separated populations of Willow Ptarmigan in Manitoba and British Columbia, Canada, by examining variation among years, over the course of the breeding season or in relation to the age of the nest, or age and condition of the female. At La Pérouse Bay, Manitoba, daily nest survival increased linearly throughout the season, with moderate annual variation. Nests also had higher daily survival during laying and late in incubation, and lower survival early in incubation. At Chilkat Pass, British Columbia, daily nest survival varied strongly by year and nests had higher survival early and late in the season, but survival was not affected by the age of the nest. At both sites, but especially at Chilkat Pass, periods of lower nest survival tended to coincide with peak breeding periods, suggesting predators may adjust their search effort based on the likelihood of locating nests. Neither female age nor condition were included in the best models. Thus, in both ptarmigan populations, nest survival patterns appeared to be influenced more by ecological factors than by individual characteristics of breeding females. The extent of annual variation and seasonal patterns may have differed between sites due to the different predator and alternative prey communities.


1986 ◽  
Vol 19 (4) ◽  
pp. 243-245 ◽  
Author(s):  
Artur da S. Pinto ◽  
Dalva N. da C. Bento

The C. cerifera palm tree (carnaúba) is widely distributed in the Northeastem Brazil, including the State of Piauí. This investigation revealed that R. nasutus is the ortly triatomine species captured on that palm tree, in five different localities. 78% of palm trees were infested with triatomines, and 4.0% were infected with flagellates morphologically and biologically indistinguishable from Trypanosoma cruzi. Birds, rodents and marsupials were found as major blood meai sources for R. nasutus.


2005 ◽  
Vol 62 (11) ◽  
pp. 2649-2660 ◽  
Author(s):  
Geoffrey B Steinhart ◽  
Nancy J Leonard ◽  
Roy A Stein ◽  
Elizabeth A Marschall

We studied how storms, angling, and nest predation during angling affected smallmouth bass (Micropterus dolomieu) nest survival in the Bass Islands, Lake Erie, Ohio, USA. Increasing angler effort and introduction of an exotic nest predator, round goby (Neogobious melanostomus), have raised concerns about smallmouth bass recruitment in Lake Erie. We surveyed smallmouth bass nests and calculated daily survival rates for nests assigned to different angling treatments: control, angling without predation, or angling with predation treatments. Only 30% of control nests were successful compared with 11% of angling without predation and 14% of angling with predation treatments. We used the Mayfield method and maximum likelihood models in the program MARK to estimate the survival rates for nests of different treatments and exposed to different numbers of storms. Although nest predators consumed about 35% of broods during angling, daily nest survival rates of both angling treatments were similar. Angling reduced nest survival compared with controls by approximately 5%. Storms reduced both nest success and daily survival. The best model predicting daily nest survival included the added effects of angling treatment and number of storms. Thus, whereas storms and angling affected smallmouth bass nest survival, nest predation during angling did not.


2020 ◽  
Vol 46 (4) ◽  
pp. 307-318
Author(s):  
Djamel Ouis

Palm trees, like all other tree species, are living entities that may be subject to the attack of several natural agents which affect the strength of the trunk. The most serious of these damaging agents are parasites and rot fungi, which proliferate in the substance of the stem, destroying its cells and fibers and weakening it. Consequently, this decay affects the physical characteristics of the modes of vibration in the tree trunk regarding resonance frequency, shape, and damping. Advanced stages of rot infection in a tree trunk may reach such an extreme level that substantial amounts of its solid mass are removed, ultimately leading to a hollow trunk rather than one of substance. In cases like these, the trunk presents less resistance to forced vibrations, and the active modes affecting the cross section of the trunk exhibit decreased resonance frequency values. This paper aims to present a method based on vibrations which might be employed for tracking a specific mode of radial vibrations known as the ovalling mode. To achieve this goal, the trunk of a palm tree was set into vibration via mechanical excitation in the radial direction and its response at some specific point on the trunk was examined. This method uses a single concentrated source of excitation and two vibration sensors, which are diametrically positioned and fastened to the surface of the tree trunk. The ovalling mode might be extracted from the frequency response by adding the signals recorded by the two sensors, which are in phase for a test specimen with a perfectly circular, cylindrical shape made of homogeneous, isotropic material. This study provides a preliminary investigation into the feasibility and reliability of this nondestructive method when applied for the identification of rot hosting by the trunks of standing trees, wooden poles, and logs, as well as the level of severity of rot attack.


Sign in / Sign up

Export Citation Format

Share Document