Changes Over Time

Author(s):  
Peter A. Gell ◽  
Marie-Elodie Perga ◽  
C. Max Finlayson

Freshwater systems are continuously shaped by cyclical and directional forces of change, whether they be natural or anthropogenic. Beyond gradual transitions disturbances can reset their internal dynamics generating an abrupt ecological shift. Long-term data sets of gradual or abrupt change can be accessed by exhuming the physical, chemical, and biological remains archived in the sediment layers within lakes and wetlands. Long-term monitoring programmes offer more detailed evidence, usually over shorter time frames. In combination these records attest to the response of wetlands to climate and the impact of industrialised people. Humans have modified lake ecosystems for millennia and the condition of many wetland ecosystems have changed such that they are now regarded as novel. Long-term records provide targets for wetland restoration and can identify the main drivers of degradation. Identification of the character of modern Ramsar wetlands may be enhanced by reference to records of past state.

2013 ◽  
Vol 40 (1) ◽  
pp. 77 ◽  
Author(s):  
Mitchell B. East ◽  
J. Daren Riedle ◽  
Day B. Ligon

Context Monitoring populations of long-lived species requires continuous long-term efforts. This is especially applicable for species that have experienced declines range-wide. Aims Our study assessed the current status of a population of wild Macrochelys temminckii and compared the present results to those from a survey conducted nearly a decade ago. Methods Trapping in 2010–2011 was conducted on two creeks within the refuge, during the months of May–July. Capture data were compared with data collected by similar methods in 1997–2001. Key results The population structure of M. temminckii was dominated by juveniles, with few large adults or small juveniles detected and a missing size class was evident. Retrospective analysis of 1997–2001 data revealed that the population was likely to be in decline even then, despite high capture rates. Conclusions The M. temminckii population showed significant declines that indicated that the population had experienced stressors of unknown origin. The status of M. temminckii at the refuge is concerning, given the protection afforded this remnant population. Implications Short-term data from 1997–2001 indicated a healthy M. temminckii population, whereas longer-term data showed that the population has declined, resulting in significant demographic changes. Continued monitoring will be necessary to develop management recommendations and track the impact of implemented management practices. Longer-term monitoring of long-lived vertebrates is required to identify population trends.


2021 ◽  
Vol 37 (1) ◽  
pp. 121-147
Author(s):  
Rob Kitchin ◽  
Samuel Stehle

Abstract In this article we evaluate the viability of using big data produced by smart city systems for creating new official statistics. We assess sixteen sources of urban transportation and environmental big data that are published as open data or were made available to the project for Dublin, Ireland. These data were systematically explored through a process of data checking and wrangling, building tools to display and analyse the data, and evaluating them with respect to 16 measures of their suitability: access, sustainability and reliability, transparency and interpretability, privacy, fidelity, cleanliness, completeness, spatial granularity, temporal granularity, spatial coverage, coherence, metadata availability, changes over time, standardisation, methodological transparency, and relevance. We assessed how the data could be used to produce key performance indicators and potential new official statistics. Our analysis reveals that, at present, a limited set of smart city data is suitable for creating new official statistics, though others could potentially be made suitable with changes to data management. If these new official statistics are to be realised then National Statistical Institutions need to work closely with those organisations generating the data to try and implement a robust set of procedures and standards that will produce consistent, long-term data sets.


2021 ◽  
Vol 17 (2) ◽  
pp. 155014772199961
Author(s):  
Zhongwei Shen ◽  
Hongxi Yin ◽  
Yanjun Liang ◽  
Rigele Maao ◽  
Lianyou Jing

A routing-benefited deployment algorithm combining static and dynamic layouts is proposed, and its comprehensive performance evaluation is given in this article. The proposed routing-benefited deployment algorithm is intended to provide a suitable network deployment and subsequent data transmission approach for underwater optical networking and communication. Static nodes are anchored for long-term monitoring, and movable nodes can adjust their depths based on the virtual force and move with the variation of area-of-interest changing. Then, nodes begin to collect data that they can monitor and transmit to sink nodes. Here, the underwater wireless optical communication model is described to actualize the real environment, and the vector-based forwarding protocol is particularly considered to compare the impact of different deployment algorithms on routing. It is shown by simulation experiment results that routing-benefited deployment algorithm outperforms several existing traditional virtual force deployment algorithms in terms of coverage, lifetime, energy consumption balance, packet-loss rate, and time-delay.


1992 ◽  
Vol 49 (8) ◽  
pp. 1588-1596 ◽  
Author(s):  
Donald J. McQueen ◽  
Edward L. Mills ◽  
John L. Forney ◽  
Mark R. S. Johannes ◽  
John R. Post

We used standardized methods to analyze a 14-yr data set from Oneida Lake and a 10-yr data set from Lake St. George. We estimated mean summer concentrations of several trophic level indicators including piscivores, planktivores, zooplankton, phytoplankton, and total phosphorus, and we then investigated the relationships between these variables. Both data sets yielded similar long-term and short-term trends. The long-term mean annual trends were that (1) the relationships between concentrations of planktivores and zooplankton (including daphnids) were always negative, (2) the relationships between concentrations of zooplankton and various measures of phytoplankton abundance were unpredictable and never statistically significant, and (3) the relationships between total phosphorus and various measures of phytoplankton abundance were always positive. Over short periods, the data from both lakes showed periodic, strong top-down relationships between concentrations of zooplankton (especially large Daphnia) and chlorophyll a, but these events were unpredictable and were seldom related to piscivore abundance.


Author(s):  
Brian Miller ◽  
Hank Harlow

Our objective is to establish a long-term monitoring project that will assess the abundance and densities of selected species of mammals at sites representing five defined vegetation types found in Grand Teton National Park. The term monitoring implies data collection over multiple years. Taking long term estimations of population composition before, during, and after biotic and abiotic changes provides needed information to assess the impacts of such changes and furnish useful options for management decisions. This standardized monitoring plan will provide information on small and medium-sized mammals that will (1) assess species use of habitat, (2) monitor changes in species composition as a result of environmental change, such as precipitation and temperature, (3) produce predictive models of small and medium-sized mammal distribution based on vegetation type, and (4) analyze the impact of wolf colonization on the mammal (and plant) community.


Author(s):  
N. Dolzhenko ◽  
E. Mailyanova ◽  
I. Assilbekova ◽  
Z. Konakbay

Cloudiness and range of visibility are the most significant flight conditions for aircraft. The impact of clouds and visibility on the safety of aircraft flights, especially small aircraft, cannot be overestimated. According to the Interstate Air Committee, Kazakhstan ranks second in the number of aviation disasters. The average age of a third of Kazakhstan's small aircraft is more than 30 years. Over the past few years, 14 air accidents have occurred in the Republic of Kazakhstan, 11 of them with small aircraft. In this work, we investigate long-term data on cloudiness and visibility at the most weather-favorable airfield in Balkhash, for the possibility of safe and economical flights of small aircraft and planning training flights.


Author(s):  
Julia Nowack ◽  
Christopher Turbill

AbstractMaintaining a high and stable body temperature as observed in endothermic mammals and birds is energetically costly. Thus, it is not surprising that we discover more and more heterothermic species that can reduce their energetic needs during energetic bottlenecks through the use of torpor. However, not all heterothermic animals use torpor on a regular basis. Torpor may also be important to an individual’s probability of survival, and hence fitness, when used infrequently. We here report the observation of a single, ~ 5.5 h long hypothermic bout with a decrease in body temperature by 12 °C in the native Australian bush rat (Rattus fuscipes). Our data suggest that bush rats are able to rewarm from a body temperature of 24 °C, albeit with a rewarming rate lower than that expected on the basis of their body mass. Heterothermy, i.e. the ability to withstand and overcome periods of reduced body temperature, is assumed to be an evolutionarily ancestral (plesiomorphic) trait. We thus argue that such rare hypothermic events in species that otherwise appear to be strictly homeothermic could be heterothermic rudiments, i.e. a less derived form of torpor with limited capacity for rewarming. Importantly, observations of rare and extreme thermoregulatory responses by wild animals are more likely to be discovered with long-term data sets and may not only provide valuable insight about the physiological capability of a population, but can also help us to understand the constraints and evolutionary pathways of different phenologies.


2018 ◽  
Vol 210 ◽  
pp. 04006
Author(s):  
Jana Pasáčková

Since decreasing level of knowledge of mathematics is the problem at universities, not only in the Czech Republic, we try to define some reasons for that between our students from different secondary schools. The paper discusses the results of the examinations in mathematics at the university in the Czech Republic. The aim is focused on the differences between the scores of students from different secondary schools. We compare the results of two tests which students have to pass during the semester. In addition, we compare the impact of introducing a new subject called “Math seminar”. This seminar should help students to complete their knowledge of topics from mathematics of secondary schools. We observe the improvement of students who passed the Math seminar. We observe the impact of passing the school-leaving exam from mathematics as well. We would like to consider this as a part of a long-term monitoring of students in this study programme and re-analyze unsuccessful students after they pass the course “Math seminar”.


Sign in / Sign up

Export Citation Format

Share Document