Urban Ecosystems最新文献

Urbanization profoundly alters natural landscapes, leading to changes in species assemblages and ecological interactions. Despite increasing interest in understanding the effects of urbanization on species interactions, there is still a gap in knowledge regarding the structure of plant-herbivore networks in urban environments. Previous studies have indicated that anthropogenic impacts can alter the topology of plant-herbivore networks, making them more generalized in disturbed environments. Here, we investigate the topology of a plant-herbivore network in urban fragments of neotropical savanna in Brazil. As specialist species (i.e., those with few interactions) tend to be more sensitive to urbanization than generalist species (i.e., those with many interactions), we hypothesized that the urban savanna network would exhibit low specialization and modularity but high nestedness. We also tested if different attributes of insects (abundance, feeding guild, developmental stage, and taxon) and plants (abundance, height, and coverage) affect the diversity of their interactions at the species level. Contrary to our expectations, the network exhibited higher specialization and modularity than expected by null models, indicating urban environments may foster levels of specialization comparable to observed in previous studies for wild savannas. Regarding the species-level descriptors, we found that different characteristics of insect and plant species affect the diversity and specialization of their interactions. Our results showed that adult insects have higher degree and centrality in shaping the network, possibly attributed to their increased mobility and capacity to link various segments of the network. Similarly, chewing insects and thrips (Thysanoptera), known for their generalist interactions with plants, had higher number of interactions and were central within the network. Furthermore, larger plant species had a higher degree and greater betweenness centrality, while plant species with greater cover had lower specialization compared to herbs. This indicates that plant species with greater structural complexity accumulate more generalized interactions. Our results also show that more abundant species, both insects and plants, had a higher number of interactions and greater centrality in the network. Our study provides insights into the structure of plant-herbivore networks in urban savanna fragments, contributing to our understanding of species interactions in urban environments and their response to anthropogenic pressures.

Rats are a problem in cities worldwide, particularly in low-income neighborhoods. Urbanization works (e.g. construction, excavations, demolition, etc.) in these neighborhoods must be a priority to improve the quality of life of their residents. The disturbances generated by these works can destroy the habitats of rodents, forcing them to seek new shelters in nearby areas, such as homes and human structures, taking advantage of rubble and construction materials that offer ideal conditions for their survival. However, limited research has focused on how infrastructural works affect the dispersion of rodents to surrounding areas. The current study aimed to evaluate the effectiveness of a rodent control program implemented during infrastructural works and its effect on the spatiotemporal dynamics of rodent population in a low-income neighborhood in Buenos Aires, Argentina. For three months, multiple infrastructural works were carried out in the neighborhood. Rodent control measures and estimation of rodent activity were carried out jointly by installing chemical box stations and contact glue traps throughout the neighborhood. We carried out a generalized additive mixed model to assess spatiotemporal changes and identify factors influencing rodent activity during the infrastructural intervention. Our results revealed that the proximity to construction works affected rodent activity, with higher infestations closer to work sites. However, after the initial 30-day period, rodent activity increased with distance. Also, remote sites located more than 150 m away exhibited a constant level of rodent activity throughout the entire study period. The findings suggest that rodent control strategies should prioritize control interventions within a 150-meter radius for at least the first month following the commencement of construction works. This ecological knowledge contributes to form a robust framework for evidence-based rat management in urban environments and provides valuable insights for urban planners, pest control professionals, and public health authorities.

Seed dispersal has been an indispensable ecosystem process mediated by biotic and abiotic vectors. Animal-mediated seed dispersal, such as endozoochory, has supported plants to sustain and establish in new locations. However, increasing urbanisation make feces deposition sites as a detrimental factor for the successful seed establishment. In this regard, this study explores the deposition of feces across the eight natural urban forest fragments with varying urbanisation rates in Tokyo-Yokohama, one of the largest urban agglomerations in the world. Paved roads within the forest fragments were surveyed for feces deposition and the urbanisation rate was estimated for all the studied sites. We found 1381 feces deposited on the paved roads, with the highest in ‘Sagamihara Chuo green space’ (n = 673) and the second highest in ‘Yokohama National University’ forest area (n = 488). This study revealed a strong influence of urbanisation on feces deposition in the forest fragments. Birds were the prominent group of animals that deposited feces on paved roads. This is the first study systematically showing the influence of urbanisation on transforming the seed dispersal service by animals into potential low services due to seed wastage in feces deposited on paved roads. Urban forest management needs to consider the impact of urbanisation on not just species diversity, but the interactions and services provided by species.

While urban river restoration has become mainstream in the Global North, it remains scarce in Latin America, where most literature focuses on water quality, stream habitats, and watershed assessment, but planning and implementation lag behind. Colombia is undergoing a paradigm shift after pioneering the integration of green and blue infrastructure (GBI) into urban planning in the early 2000s (namely Estructura Ecológica Principal). A surge in river renaturalization initiatives is underway, with large and intermediate cities planning and executing projects. We systematically assessed the integration of rivers and GBI into local policies (Planes de Ordenamiento Territorial) and found widespread and strong recognition of streams, wetlands, and ecosystem services in urban planning, higher than previously reported. Most cities emphasize river multifunctionality, ecological connectivity, public space, and recreation, as well as disaster risk reduction, advancing toward sustainable urban water and drainage systems. However, significant gaps persist regarding climate change resilience, participation, and social justice. In a region marked by high inequality, pre-existing spatial exclusion could be amplified by urban renewal, greening, and tourism due to unfair resettlement conditions and gentrification. Such trade-offs can undermine the ecological and social benefits of restoration. We highlight the crucial role of civil society and grassroots activism in protecting and defending urban commons and conclude by recommending a critical examination of GBI and river restoration efforts in Latin America. Colombia’s case can serve as both a reference and a cautionary tale for other cities in the region to achieve outcomes that promote equity and justice amid pressing social and environmental challenges.

Prey-predator interactions are fundamental to ecosystem balance, with predators regulating prey populations. Yet, the degree of this interaction varies, depending on the conditions and structure of the ecosystem. We investigated the influence of leaf herbivory, predator types, and levels of urbanisation on the predation risk of artificial caterpillar prey within an urban-agricultural landscape in southcentral Mindanao, Philippines. Four hundred and seventy-three (31.53%) of the 1500 artificial caterpillars exposed in the field were predated. While there was a significant difference in the predation frequency of caterpillar prey between herbivory treatments, our generalised linear mixed model showed a marginal influence on predation risk, but predator type and local landscape showed significant and relatively higher effects. Arthropods were the most significant predators followed by mammals, birds, and reptiles. Furthermore, an increasing proportion of urban developed areas was associated with a decreased risk of predation in artificial caterpillar models. This study implies that regardless of the specific foraging locations chosen by the arthropod prey, predators are likely to prey on available prey in urban and agricultural landscape environments. Our study provides additional evidence that urbanisation can reduce prey-predator interactions. Considering our findings, we suggest that increasing tree cover and green spaces may effectively improve prey-predator interactions in urbanised areas.

Shenzhen, a bustling metropolis in China, is currently grappling with the delicate balance between urban expansion and environmental preservation. This study finds that the disintegration of habitats due to urban development in Shenzhen city significantly impacts the ecosystem of animals and plants, detrimentally altering their living conditions. The study results reveal that the expansion of construction land in China has surged by an impressive 84.39% between 2000 and 2020, which has come at the cost of diminishing wetlands, farmland, and woodlands by 57.24%, 16.58%, and 1.86%, respectively. Between 1980–2020, the urban expanse of Shenzhen expanded dramatically, growing from 16.0 square kilometres to 850.2 square kilometres. This transformation was primarily driven by the rapid conversion of forested areas, which saw a staggering decrease of approximately 300% to 780 km² by 2020. Additionally, half of Shenzhen’s expansion can be attributed to the transformation of agricultural land, with an additional 40% stemming from the clearing of forests and approximately 9% resulting from the decrease in water resources. Furthermore, non-urban green spaces, particularly built-up areas, have significantly expanded, now encompassing approximately 60% of the city in 2018. Therefore, based on the existing literature and authoritative legal texts, this study aims to examine the legal frameworks of the Shenzhen government and, along with China’s national legislation, to make room for wildlife and biodiversity conservation in a metropolis like Shenzhen.

Urban ecosystems can provide diverse habitats for enhancing pollinator biodiversity. Here, we describe efforts to initiate a community wide conversation around pollinator friendly yard (lawn and garden) management practices in Appleton, Wisconsin, USA, using a series of projects. We began with wild bee census work at local environmental education centers and city parks, then expanded to community science common gardens as part of the “Bring Your Own Bees” project, and shifted gears to implement a No Mow May campaign. We outline the timeline of events that led to the creation of the Pollenablers group, which allowed us to work alongside city legislators and community leaders to bring No Mow May to Appleton. Through our experiences, we learned about the timescales and processes of small-town government structures, and the challenges of engaging in open science that garners media attention. Engaging in community conversations across scales was an essential component, including individual discussions, co-generation of research goals in alignment with community builders at Pollenablers meetings, and collaborating with political leaders to align legislative resolutions with research objectives. We hope that our insights inspire others to continue to “bee” change-makers in their local communities, and build systems of reciprocity to cultivate richer human, and more biodiverse, urban ecosystems.

Urbanization and fragmentation of habitat are major drivers of population declines in wildlife in cities. This study evaluated fragmentation of aquatic systems in the context of urbanization, using the Eastern long-necked turtle Chelodina longicollis as a model as it is a generalist species, highly vagile and engages in regular overland migration. During two seasons (2020-22), we compared C. longicollis demography in stormwater ponds in two distinct urban drainages, one with greater habitat connectivity (lower road network and an unmodified creek) and one with lower habitat connectivity (higher road network and stormwater drains) in Canberra, south-eastern Australia. Most of the parameters related to habitat (pond age and size) and food requirements (phosphate and prey biomass) for C. longicollis were similar between the two drainages, in addition to proportion of females, overall size-frequency distributions and population size (corrected for variation in capture probability). However, there was a significant effect of the interaction between pond habitat connectivity and pond size with population sizes increasing more steeply in higher than in lower connectivity sites (F_{1, 4} = 14.3, p = 0.02). We also recaptured a marked turtle from a previous study in the drainage with more habitat connectivity, 14 years later and 15 km from its initial point of capture. This demonstrates the ability of the species to move within an urbanized context. Despite evidence of C. longicollis being resilient to urbanization, dispersal constraints seem to affect population dynamics and long term population viability in areas with low habitat connectivity.

Urbanization has increased wealth disparity within the United States, impacting the urban landscape and species interactions. In particular, the interactions between street trees and the arthropod communities that live among them may be modified by both human population densities across urban to suburban locations, as well as income levels within these areas. We examined the effect of land use type (urban vs. suburban) and median household income on variation in leaf damage and arthropod abundance of red maples (Acer rubrum) in the District of Columbia metropolitan region. We compared these levels of leaf damage to rates observed in a nearby temperate deciduous forest. We predicted leaf damage would be positively correlated with urbanization (forested < suburban < urban) and negatively correlated with neighborhood income level (low > medium > high). Instead, we observed higher levels of leaf damage on trees in the forest environment compared to the urban and suburban areas. Leaves from urban medium and high-income areas were less likely to exhibit herbivore damage than those from suburban areas. Of the leaves with damage, those in urban high-income and suburban low-income areas exhibited the most leaf area missing. These trends may be related to specific factors associated with urbanization and income level, such as impervious surface coverage and tree coverage. This study highlights differences in biotic interactions across individual neighborhoods and the importance of including socio-economic variables when examining species interactions in urban environments.

Urban areas are growing rapidly across the globe. Such environments present specific challenges to wildlife. Resources can be highly fragmented in space and time, accompanied by specific risks and opportunities that can emerge from proximity with humans. Overall, these have been shown to lead to specific activity patterns in wildlife, which tend to restrict their space use accordingly to avoid encounters with humans. Yet, some foraging opportunities supplied by humans can also attract wildlife. Urban-dwelling species would therefore benefit from learning when and where to exploit human derived food. Here, we investigate how birds exploit areas of different degrees of urbanization and if they do so with specific time patterns. We used the example of feeding sulphur-crested cockatoos (Cacatua galerita) in Sydney, Australia. We combined tracking birds to identify key resources, and a citizen science approach to investigate human-wildlife interactions in the urban landscape. Our data suggest that SCC do not use all parts of their home range equally, but use green spaces as roosting and foraging areas, while facultatively using more urbanized areas at specific times when they are the most rewarding. This implies a role for sophisticated time and place learning, with birds matching activity to human patterns. This study builds on the literature investigating human-animal interactions, expanding our understanding of animals’ exploitation of human behavior. Our results highlight the unique opportunity that studies on urban wildlife have for understanding urban biodiversity establishment, maintenance, and cognitive ecology.