Deterministic, random, or in between? Inferring the randomness level of wildlife movements

Background When assessing connectivity, it is crucial to rely on accurate modeling frameworks that consider species movement preferences and patterns. One important aspect is the level of randomness or unpredictability in the route selection. In this respect, traditional approaches (based on least-cost path or circuit theory) consider species movements unrealistically as totally deterministic or as totally random. A recent approach (randomized shortest path) advocates for choosing intermediate levels of randomness through a single parameter. This parameter may be optimized by validating connectivity surfaces developed from different levels of randomness against observed movement data. However, connectivity models are seldom validated, and it is still unclear how to approach this task. To address this knowledge gap, this paper aims at comparing different validation methods to infer the optimal randomness level in connectivity studies. Additionally, we aimed to disentangle the practical consequences of applying traditional connectivity approaches versus using an optimized level of movement randomness when delineating corridors. Methods These objectives were accomplished through the study case of the Iberian lynx, an endangered species whose maintenance and recovery depend on the current connectivity among its population nuclei. We firstly determined a conductance surface based on point selection functions accounting for the behavioral state (territorial or exploratory) of individuals. Secondly, we identified the level of randomness that better fits lynxes’ movements with independent GPS locations and different validation techniques. Lastly, we delineated corridors between lynx population nuclei through a) the randomized shortest path approach and the extreme and optimal levels of randomness of each validation method, and b) the traditional connectivity approaches. Results According to all used validation methodologies, models with intermediate levels of randomness outperformed those with extreme randomness levels representing totally deterministic or random movements. We found differences in the optimal randomness level among validation methods but similar results in the delineation of corridors. Our results also revealed that models with extreme randomness levels (deterministic and random walk) of the randomized path approach provided equivalent corridor networks to those from traditional approaches. Moreover, these corridor networks calculated with traditional approaches showed notable differences in patterns from the corridor network calculated with an optimized randomness level. Conclusions Here we presented a connectivity model with a solid biological basis that calibrates the level of movement randomness and is supported by comprehensive validation methods. It is thus a step forward in the search and evaluation of connectivity approaches that lead to improved, efficient, and successful management actions.

Well Testing of Fracture Corridors in Naturally - Fractured Reservoirs (NFR)

Geological folding/faulting may create naturally fractured reservoirs containing a semi-parallel system of sparsely-spaced fracture corridors. The pressure behavior of wells completed either in highly conductive corridors (fracture wells) or in the exclusion zone (matrix wells) would be quite different. In this study, a unique simulation model has been built for corridor type naturally fractured reservoirs by combining a local model of fracture well or matrix well with adjacent fracture corridor(s) and a “homogenized” global model of the remaining corridor network. The global model generalizes the corridor network using the single-porosity and radial permeability approach, which is verified as being sufficiently accurate. Pattern recognition technique is used to analyze diagnostic plots of pressure drawdown generated by simulated flow tests with commercial software (CMG). This study aims to build a new simulation model for corridor-type NFRs and apply the well testing technique to differentiate corridor-type NFRs from conventional NFRs, detect the well’s location, and estimate reservoir properties. This study also employs cumulative logit statistics to assess the accuracy of the estimated well-to-corridor distance.

Delineating an Integrated Ecological and Cultural Corridor Network: A Case Study in Beijing, China

This study shows that an integrated ecological and cultural corridor network can help guide city development strategies to better preserve ecological and cultural assets. Traditionally, protection zones and suitable development areas are often identified by separately considering natural elements of the ecosystem and elements of cultural significance. To achieve the purpose of cohesively protecting areas of ecological and/or cultural significance, we have developed a corridor-based spatial framework by integrating ecological and cultural assets. Ecological sources are identified by combining protection prioritization, nature reserves, and water bodies. Ecological corridors are delineated by using the minimum cumulative resistance (MCR) model on a resistance surface constructed from land-use data to connect ecological sources. Ecologically important areas are then delineated by creating a 5-km buffer zone from ecological sources and ecological corridors. Cultural corridors are historical routes and rivers surrounded by abundant cultural nodes. Like ecologically important areas, culturally important areas are delineated by creating a 5-km buffer zone from cultural corridors. Comprehensive regions are the overlap of ecologically and culturally important areas. Finally, the integrated network connects all comprehensive regions following ecological corridors and cultural corridors in such a way that the largest number of ecological sources and cultural nodes are reached. We applied this framework in Beijing, China, and the results show that there are 2011 km2 of ecological sources, 30 ecological corridors, 423 cultural nodes, seven cultural corridors, and 10 comprehensive regions covering 2916 km2 in the integrated network. The framework adds new insights to the methodology of considering ecological and cultural assets together in developing protection and development strategies.

Analisis Infrastruktur Sistem Jaringan Jalan Dan Pejalan Kaki Pada Jl. Legian, Kuta, Badung

Legian street is the main road that connects Kuta with Seminyak in Bali. The length of this road is around 1.5 kilometers filled with various shops, bars, hotels and clubs. Legian street is a primary local road with the width about 7.5 meters but with a solid volume of vehicles, especially in the morning and evening caused this corridor is prone to congestion. Quality level of infrastructure facilities, influenced by the quality of planning and supervision, one of the indicators of poor infrastructure, especially road and pedestrian networks, is congestion. This study uses descriptive qualitative research with a rationalistic approach based on reality in the field with primary data obtained from observations, documentation that is integrated with the policies of the Local Regulations of Badung Regency, RTRW Regency of Badung. The results of the study showed that there were still many incomplete pedestrian facilities and the transfer of pedestrian facilities which caused the road corridor network infrastructure to be prone to congestion.

Statistical Assessment of Alternative Methods for Well Recovery Estimation in Naturally Fractured Reservoirs With Fracture Corridors

Reliable predictions of well recovery are crucial for designing reservoir development. In the bottom-water naturally-fractured reservoirs (NFRs), comprising a network of distributed fracture “corridors,” spacing (and apertures) of the corridors varies throughout the reservoir. This makes oil well’s recovery a probabilistic variable as it depends upon uncertain well’s location in the network. The uncertainty is two-fold; it concerns well’s location within corridor network and well’s possible intersection with the nearest corridor. In any network’s location (with closely- or sparsely–spaced corridors), wells may intercept fracture corridors (fracture well) or go in-between two corridors in a matrix block (matrix-well). A simplified way of estimating well recovery is to ignore well’s location within corridor network and consider only probability and performance of fracture well and matrix well in a statistically-equivalent reservoir with uniform spacing and aperture equal to their expected values derived from their known statistics. Another (fully probabilistic) method considers the combined probabilities of the well’s location in the network and being a fracture well or matrix well. The study evaluates discrepancy between the two methods, explains its statistical nature, and demonstrates their implementation in a corridor-type NFR described in the literature. In the study, recovery process is simulated by coupling the inner (near-well) zone’s discrete single-porosity flow model with the outer zone Dual Porosity Dual Permeability (DPDP) simulator. The matrix well’s inner zone extends from the well to the nearest corridor and for the fracture well inner zone covers the corridor and adjacent matrix blocks. In the simulations, matrix and fracture-wells are operated at maximum rate constrained by minimum downhole flowing pressure and the surface handling limit. The study is performed using statistical data from a corridor-type NFR with power-law-distributed spacing size from 19 ft to 153 ft and corridor apertures varying from 8ft to 31ft correlated with the spacing. The simplified method gives recovery values ranging from 28% to 37%, and the single value of total recovery 33% — normalized by the matrix and corridor size fractions of the total reservoir area. Alternatively, the probabilistic method gives two separate distributions of the fracture and matrix wells’ recoveries that are weighted by their probability and converted to a single distribution of total recovery using statistical concept of weighted average. The probabilistic estimation gives higher values of recovery — from 32% to 38% with the expected value of 36.6%. Moreover, there is a considerable 30% probability of having recovery greater than 36.6%. A mathematical proof provides explanation why the probabilistic method gives recovery estimate greater than that from the simplified method. Another advantage of the method is the cumulative probability plot of well recovery that, in practical applications, would let operators make reservoir development decisions based upon the risk-benefit consideration.

Urban Ecological Corridor Network Construction: An Integration of the Least Cost Path Model and the InVEST Model

Under the background of urban expansion, ecological protection cannot be delayed. The construction of ecological networks is of considerable significance to ecosystem services. However, in the process of constructing a corridor network, there is no uniform standard for the selection of ecological sources and the determination of cost factors. The InVEST model is an effective complement to ecosystem service assessment for sensitively measuring external threats and their threat intensity. Therefore, taking Wuhan as an example, we combined InVEST and the least cost path model (LCP) to construct a multi-target corridor network with comprehensive cost factors for birds and small terrestrial mammals. The results showed that: (1) The InVEST model provided a reliable basis for ecological source screening by demonstrating the distribution of habitat quality. (2) The corridor with a length of 12–25 km presented a “U” shape, and the impact of urbanization on small terrestrial mammals was more significant than that of birds. (3) The integrated network pattern proposed by the “point-line-plane” principle would provide a reference for urban ecological construction and sustainable development.