Arrays of porous fences, ≈12 ha in 2014 and ≈ 15 ha in 2015, were constructed in the Oceano Dunes State Vehicular Recreation Area to evaluate their effectiveness to reduce sand flux and affect local ...PM10 dust concentrations. The 1.22 m high, ≥244 m long, ≈50% porous fences were placed 10 fence heights apart in 2014 and 7 in 2015. Measurements of sand flux through the arrays indicated that it diminished exponentially with increasing distance, reaching equilibrium at ≈93 fence heights for the 10 h spacing and ≈27 fence heights for the 7 h spacing. Fences spaced 7 h apart reduced sand flux for the entire area by 78%, and 86% for the area ≥27 h. Fences spaced at 10 h reduced sand flux for the entire area by 40%, and 56% for the area ≥93 h. PM10 monitoring upwind and downwind of the array and in the absence of the array in 2015, indicated that the downwind PM10 concentration was less than the upwind for the fence array, whereas in the absence of fences PM10 increased in the downwind direction over the same fetch distance, suggesting the presence of the fences was reducing the flux of PM10 from within the fence array.
•The effectiveness of multiple porous fence arrays to reduce sand flux and local PM10 concentrations was evaluated.•Effectiveness to reduce sand flux scales with inter-row spacing.•Sand flux decreases exponentially with horizontal distance and the rate of reduction is a function of fence spacing.•Porous fences decrease sand flux at a faster rate with into the array than an array of solid elements designed to achieve the same level of control.•The PM10 concentration at the downwind edge of the array was less than the upwind, suggesting flux of PM10 from the sand was reduced.
Abstract
Wooden fences, a permeable structure, have become a nature-based solution for supporting traditional structures to restore mangrove forests along the Mekong deltaic coasts. Even though prior ...studies have explored a number of hydraulic functions of these fences, an in-depth investigation into the influence of fence width on wave dissipation and damping is needed to consider. Therefore, this paper employs a numerical approach to thoroughly examine the impact of fence width on wave damping. The findings illustrate the substantial role of fence width in governing the dissipation of incoming waves. The correlation between the transmission coefficient and the fence width is established. This relationship also concludes that the larger the fence thicknesses, the lower the transmission coefficients. Notably, the study also identifies that the transmission coefficient experiences a slight decline beyond a certain width threshold.
Investigations of the links between human infrastructure and ecological change have provided eye-opening insights into humanity’s environmental impacts and contributed to global environmental ...policies. Fences are globally ubiquitous, yet they are often omitted from discussions of anthropogenic impacts. In the present article, we address this gap through a systematic literature review on the ecological effects of fences. Our overview provides five major takeaways: 1) an operational definition of fencing to structure future research, 2) an estimate of fence densities in the western United States to emphasize the challenges of accounting for fences in human-footprint mapping, 3) a framework exhibiting the ecological winners and losers that fences produce, 4) a typology of fence effects across ecological scales to guide research, and 5) a summary of research trends and biases that suggest that fence effects have been underestimated. Through highlighting past research and offering frameworks for the future, we aim with this work to formalize the nascent field of fence ecology.
Pasture management in Australia's dairy industry requires the manual shifiting of temporary electric fences to maintain pasture quality and growth. Virtual fencing presents an alternative to save ...time and labour costs. We used automated virtual fence (VF) collars to determine the variation in learning of the virtual fence stimuli, and evaluated the success of the technology to contain cows in a predetermined area of pasture. Twelve Holstein-Friesian non-lactating multiparous dairy cows were fitted with the collars, and a VF was used to restrict cows to two grazing allocations (G1 and G2) across six days. Cows received an audio tone (AT) when they approached the virtual fence, and a paired electrical pulse (EP) if they continued forward. The VF contained cows within predetermined areas for 99% of time, but cows spent the least time near the fence (
< 0.01). The number of stimuli reduced through time, demonstrating the ability of cows to learn the VF (
= 0.01). However, the mean number of EP per day ranged from 1 to 6.5 between individuals (
< 0.01). Therefore, successful containment may have a welfare cost for some individuals. Further work should focus on this individual variation, including measures of welfare.
Small mammal species are declining across northern Australia. Predation by feral cats Felis sylvestris catus is one hypothesised cause. Most evidence of cat impacts on native prey comes from islands, ...where cat densities are often high, but cats typically occur at low densities on mainland Australia. We conducted a field experiment to measure the effect of predation by low‐density cat populations on the demography of a native small mammal. We established two 12·5‐ha enclosures in tropical savanna in the Northern Territory. Each enclosure was divided in half, with cats allowed access to one half but not the other. We introduced about 20 individuals of a native rodent, Rattus villosissimus, into each of the four compartments (two enclosures × two predator‐access treatments). We monitored rat demography by mark‐recapture analysis and radiotracking, and predator incursions by camera surveillance and track and scat searches. Rat populations persisted over the duration of the study (18 months) in the predator‐proof treatment, where we detected no predator incursions, but declined to extinction in both predator‐accessible compartments. In one case, cat incursions were frequently detected and the rat population was rapidly extirpated (<3 months); in the other, cat incursions were infrequent, and the population declined more gradually (c. 16 months) due to low recruitment. We detected no incursions by dingoes Canis dingo, the other mammalian predator in the area. Synthesis and applications. This is the first study to provide direct evidence that cats are capable of extirpating small mammals in a continental setting, in spite of their low population densities. This finding supports the hypothesis that predation by feral cats is contributing to declines of small mammals in northern Australia. The conservation management of native small mammals in northern Australia may require intensive control of cat populations, including large cat‐free enclosures.
Natural habitats are rapidly being converted to cultivated croplands, and crop‐raiding by wildlife threatens both wildlife conservation and human livelihoods worldwide. We combined movement data from ...GPS‐collared elephants with camera‐trap data and local reporting systems in a before–after‐control‐impact design to evaluate community‐based strategies for reducing crop raiding outside Mozambique's Gorongosa National Park. All types of experimental fences tested (beehive, chili, beehive and chili combined, and procedural controls) significantly reduced the number of times elephants left the Park to raid crops. However, placing beehive fences at a subset of key crossing locations reduced the odds that elephants would leave the Park by up to 95% relative to unfenced crossings, and was the most effective strategy. Beehive fences also created opportunities for income generation via honey production. Our results provide experimental evidence that working with local communities to modify both animal behavior and human attitudes can mitigate conflict at the human–wildlife interface.
As human activities expand globally, there is a growing need to identify and mitigate barriers to animal movements. Fencing is a pervasive human modification of the landscape that can impede the ...movements of wide‐ranging animals. Previous research has largely focused on whether fences block movements altogether, but a more nuanced understanding of animals' behavioural responses to fences may be critical for examining the ecological consequences and prioritizing conservation interventions.
We developed a spatial‐ and temporal‐explicit approach, Barrier Behaviour Analysis (BaBA, available as an r package), to examine individual‐level behaviours in response to linear barriers. BaBA classifies animal‐barrier encounters into six behaviour categories: quick cross, average movement, bounce, back‐and‐forth, trace and trapped. We applied BaBA to wide‐ranging female pronghorn Antilocapra americana and mule deer Odocoileus hemionus in an area of western Wyoming, USA, with >6,000 km of fencing.
We found both species were extensively affected by fences, with nearly 40% of fence encounters altering their normal movements, though pronghorn were more strongly affected than mule deer. On average, an individual pronghorn encountered fences 250 times a year—twice the encounter rate of mule deer. Pronghorn were more likely to bounce away from fences, whereas deer engaged in more back‐and‐forth, trace and average movement near fences.
We aggregated these behavioural responses to demonstrate how BaBA can be used to examine species‐specific fencing permeability and to identify problematic fence segments in order to guide fence modification or removal.
Synthesis and applications. Our work provides empirical evidence on how fences affect wildlife movement. Importantly, Barrier Behaviour Analysis (BaBA) can be applied to evaluate other linear features (such as roads, railways and pipelines) and habitat edges, enhancing our ability to understand and mitigate widespread barrier effects to animal movement.
摘要
随着人类活动在全球范围内持续扩张, 生态学家需要识别动物迁移障碍并缓解其影响。作为一种普遍存在的人类改造景观的方式, 围栏严重限制了广域活动物种的迁移。此前研究大多关注围栏是否完全阻断了动物迁移, 但忽略了围栏可能造成的其他行为反应。这些反应可能对量化围栏的生态后果及优化保育策略至关重要。
我们研发了一种基于时空数据来衡量个体对线状障碍行为反应的方法, 称为障碍行为分析 (BaBA, 可通过R 包获取) 。BaBA将动物‐障碍相遇事件划分成六种类型: 快速跨越, 日常活动, 反弹, 徘徊, 追踪, 以及围困。我们应用BaBA分析了美国怀俄明州西部的雌性叉角羚 Antilocapra americana 和骡鹿 Odocoileus hemionus 的迁移活动。该区域围栏总长度超过6000千米。
我们发现两个物种都广泛受到了围栏影响, 接近40%的围栏相遇事件改变了动物的正常迁移活动。叉角羚受到的影响较骡鹿更大。每只叉角羚平均每年遇到围栏250次, 是骡鹿的两倍。骡鹿在围栏边表现出更多的徘徊, 追踪, 及日常活动, 而叉角羚更可能从围栏反弹。
综合这些行为反应, 我们展示了如何使用BaBA来量化特定物种的围栏可通过性, 并以此鉴别对动物迁移影响较大的围栏段, 来指导围栏改造或移除。
总结和应用: 本研究为理解围栏如何影响野生动物迁移提供了实验证据。更重要的是, BaBA适用于研究动物对其他线状障碍 (如道路, 铁路, 和运输导管) 和生境边界的行为反应。这些应用可以促进我们理解障碍效应如何作用于动物行为, 并提出相应的缓解办法。
Our work provides empirical evidence on how fences affect wildlife movement. Importantly, Barrier Behaviour Analysis (BaBA) can be applied to evaluate other linear features (such as roads, railways and pipelines) and habitat edges, enhancing our ability to understand and mitigate widespread barrier effects to animal movement.
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