Effect of Urbanization on Vegetation in Riparian Area: Plant Communities in Artificial and Semi-Natural Habitats

Riparian areas are local hot spots of biodiversity that are vulnerable and easily degraded. Comparing plant communities in habitats with different degrees of urbanization may provide valuable information for the management and restoration of these vulnerable habitats. In this study, we explored the impact of urbanization on vegetation communities between artificial and semi-natural habitats within two rivers with different levels of development. We compared species richness, types of vegetation, and composition patterns of the plants in our study. In artificial habitats, the sites with relatively high levels of urbanization had the highest species richness, while in semi-natural habitats, the highest species richness was recorded in the less urbanized sites. Furthermore, every component of urbanization that contributed to the variation of species richness was examined in the current study. In artificial habitats, the proportion of impervious surface was the strongest predictor of the variation in species richness and was associated with the richness of alien, native, and riparian species. In semi-natural habitats, most of the richness of alien and native species were associated with the distance to the city center, and the number of riparian and ruderal species was significantly related to the proportion of impervious surface. Moreover, we found that a high level of urbanization was always associated with a large abundance of alien and ruderal species in both artificial and in semi-natural habitats. We recommend the methods of pair comparison of multiple rivers to analyze the impact of urbanization on plant species in riparian areas and have suggested various management actions for maintaining biodiversity and sustainability in riparian ecosystems.

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Relationship between lake area and distance from the city centre on lake-dependent resident and migratory birds in urban Bangalore, a tropical mega-city in Southern India

Journal of Urban Ecology ◽

10.1093/jue/juab028 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Ravi Jambhekar ◽

Kulbhushansingh Suryawanshi ◽

Harini Nagendra

Keyword(s):

Species Richness ◽

Migratory Birds ◽

Bird Species ◽

Southern India ◽

City Centre ◽

Lake Area ◽

Bird Species Richness ◽

Impact Of Urbanization ◽

The Impact ◽

The City

Abstract Urbanization is one of the major causes of biodiversity loss worldwide. Some species are able to adapt to urbanization, whereas others perish. Studies on long-term effects of the impact of urbanization on species diversity and abundance patterns are especially lacking from tropical cities. We seek to assess the relationship between urbanization and species richness of lake-dependent birds in Bangalore, a tropical mega-city in Southern India. We specifically ask: (i) How is bird species richness related to the size of the lake? (ii) How is bird species richness in Bangalore’s lakes related to the degree of urbanization? We used data from 2014 to 2019, collected from eBird—an online database that collates information on bird observations globally. Both lake area and distance from the city centre are correlated to species richness, with larger lakes supporting more bird species. As distance from the city centre increased (i.e. urbanization decreases), bird richness increased. Overall, in the city of Bangalore, migratory birds have declined while many lake-dependent resident birds seem to be increasing over the past 5 years. We hypothesize that birds that roost and nest in trees appear to be increasing. To confirm this, further research taking a trait-based approach is required. Urbanization appears to have species-specific impacts on lake-dependent birds in this tropical city, with certain groups of birds faring better than others. This research adds to the significant paucity of studies of the impact of urbanization on biodiversity in the urban tropics.

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Assessing the impact of human trampling on vegetation: a systematic review and meta-analysis of experimental evidence

10.7287/peerj.preprints.315 ◽

2014 ◽

Author(s):

Oliver L. Pescott ◽

Gavin Stewart

Keyword(s):

Systematic Review ◽

Random Effects ◽

Plant Communities ◽

Life Form ◽

Conservation Management ◽

Meta Analysis ◽

Vegetation Recovery ◽

Management Decisions ◽

Natural Habitats ◽

The Impact

Vegetation trampling resulting from recreation can adversely impact natural habitats, leading to the loss of vegetation and the degradation of plant communities. A considerable primary literature exists on this topic, therefore it is important to assess whether this accumulated evidence can be used to reach general conclusions concerning vegetation vulnerability to inform conservation management decisions. Experimental trampling studies on a global scale were retrieved using a systematic review methodology and synthesised using random effects meta-analysis. The relationships between vegetation recovery and each of initial vegetation resistance, trampling intensity, time for recovery, Raunkiaer life-form (perennating bud position), and habitat were tested using random effects multiple meta-regressions and subgroup analyses. The systematic search yielded 304 studies; of these, nine reported relevant randomized controlled experiments, providing 188 vegetation recovery effect sizes for analysis. The synthesis indicated there was significant heterogeneity in the impact of trampling on vegetation recovery. This was related to resistance and recovery time, and the interactions of these variables with Raunkiaer life-form, but was not strongly dependent on the intensity of the trampling experienced. The available evidence suggests that vegetation dominated by hemicryptophytes and geophytes recovers from trampling to a greater extent than vegetation dominated by other life-forms. Variation in effect within the chamaephyte, hemicryptophyte and geophyte life-form sub-groups was also explained by the initial resistance of vegetation to trampling, but not by trampling intensity. Intrinsic properties of plant communities appear to be the most important factors determining the response of vegetation to trampling disturbance. Specifically, the dominant Raunkiaer life-form of a plant community accounts for more variation in the resilience of communities to trampling than the intensity of the trampling experienced, suggesting that simple assessments based on this trait could guide decisions concerning sustainable access to natural areas. Methodological and reporting limitations must be overcome before more disparate types of evidence can be synthesised; this would enable more reliable extrapolation to non-study situations, and a more comprehensive understanding of how assessments of intrinsic plant traits can be used to underpin conservation management decisions concerning access.

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A review of the challenges and opportunities for restoring animal-mediated pollination of native plants

Emerging Topics in Life Sciences ◽

10.1042/etls20190073 ◽

2020 ◽

Vol 4 (1) ◽

pp. 99-109 ◽

Cited By ~ 1

Author(s):

Daniel P. Cariveau ◽

Bethanne Bruninga-Socolar ◽

Gabriella L. Pardee

Keyword(s):

Climate Change ◽

Native Species ◽

Biological Diversity ◽

Local Scale ◽

Ecosystem Functions ◽

Pollen Deposition ◽

Natural Habitats ◽

Management Actions ◽

Restoration Success ◽

Scale Management

Ecological restoration is increasingly implemented to reverse habitat loss and concomitant declines in biological diversity. Typically, restoration success is evaluated by measuring the abundance and/or diversity of a single taxon. However, for a restoration to be successful and persistent, critical ecosystem functions such as animal-mediated pollination must be maintained. In this review, we focus on three aspects of pollination within ecological restorations. First, we address the need to measure pollination directly in restored habitats. Proxies such as pollinator abundance and richness do not always accurately assess pollination function. Pollen supplementation experiments, pollen deposition studies, and pollen transport networks are more robust methods for assessing pollination function within restorations. Second, we highlight how local-scale management and landscape-level factors may influence pollination within restorations. Local-scale management actions such as prescribed fire and removal of non-native species can have large impacts on pollinator communities and ultimately on pollination services. In addition, landscape context including proximity and connectivity to natural habitats may be an important factor for land managers and conservation practitioners to consider to maximize restoration success. Third, as climate change is predicted to be a primary driver of future loss in biodiversity, we discuss the potential effects climate change may have on animal-mediated pollination within restorations. An increased mechanistic understanding of how climate change affects pollination and incorporation of climate change predictions will help practitioners design stable, functioning restorations into the future.

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Antigonon leptopus invasion is associated with plant community disassembly in a Caribbean island ecosystem

Biological Invasions ◽

10.1007/s10530-021-02646-w ◽

2021 ◽

Author(s):

Maarten B. Eppinga ◽

Elizabeth A. Haber ◽

Luke Sweeney ◽

Maria J. Santos ◽

Max Rietkerk ◽

...

Keyword(s):

Species Richness ◽

Community Structure ◽

Plant Community ◽

Plant Communities ◽

Biodiversity Loss ◽

Native Plant ◽

Tropical Islands ◽

Caribbean Island ◽

Occurrence Patterns ◽

The Impact

AbstractInvasions by non-native plant species are widely recognized as a major driver of biodiversity loss. Globally, (sub-)tropical islands form important components of biodiversity hotspots, while being particularly susceptible to invasions by plants in general and vines in particular. We studied the impact of the invasive vine A. leptopus on the diversity and structure of recipient plant communities on the northern Caribbean island St. Eustatius. We used a paired-plot design to study differences in species richness, evenness and community structure under A. leptopus-invaded and uninvaded conditions. Community structure was studied through species co-occurrence patterns. We found that in plots invaded by A. leptopus, species richness was 40–50% lower, and these plots also exhibited lower evenness. The magnitude of these negative impacts increased with increasing cover of A. leptopus. Invaded plots also showed higher degrees of homogeneity in species composition. Species co-occurrence patterns indicated that plant communities in uninvaded plots were characterized by segregation, whereas recipient plant communities in invaded plots exhibited random co-occurrence patterns. These observations suggest that invasion of A. leptopus is not only associated with reduced species richness and evenness of recipient communities in invaded sites, but also with a community disassembly process that may reduce diversity between sites. Given that A. leptopus is a successful invader of (sub-)tropical islands around the globe, these impacts on plant community structure highlight that this invasive species could be a particular conservation concern for these systems.

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Delineating the influence of water conditions and landscape on plant communities in eutrophic ditch networks

Wetlands Ecology and Management ◽

10.1007/s11273-021-09792-x ◽

2021 ◽

Author(s):

André Mauchamp ◽

Olivier Gore ◽

Jean-Marc Paillisson ◽

Benjamin Bergerot ◽

Anne Bonis

Keyword(s):

Species Richness ◽

Plant Communities ◽

Water Regime ◽

High Water ◽

Quality Parameters ◽

Water Levels ◽

Human Occupation ◽

Landscape Characteristics ◽

Management Actions ◽

Influence Of Water

AbstractMarshlands and floodplains are generally characterized by a long history of human occupation and management, with strong impacts on biodiversity. In these landscapes, ditch networks often represent the last or most significant aquatic habitat, and significantly contribute to regional biodiversity. To determine the drivers of biodiversity in ditch networks, especially the importance of the water regime, we monitored vegetation in ditches in 11 sites (independent blocks of ditch networks) of an Atlantic marshland (the Marais poitevin, France) over a 4-year period, and a panel of local environmental conditions and landscape characteristics. Large differences in the species richness and composition of ditch plant communities were observed among sites. The water regime had a predominant effect on all descriptors of ditch plant communities. High water levels combined with strong temporal variability, including drying-out periods, were found associated to the communities with the highest species richness. By contrast, water quality parameters did not influence plant communities across sites. Among landscape variables, woodland cover combined with high hedge cover along the ditches significantly influenced plant composition and species richness. These results are discussed in terms of management actions that may promote the diversity and composition of ditch plant communities and address conservation challenges.

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Exotic species richness and native species endemism increase the impact of exotic species on islands

Global Ecology and Biogeography ◽

10.1111/j.1466-8238.2011.00724.x ◽

2011 ◽

Vol 21 (8) ◽

pp. 841-850 ◽

Cited By ~ 23

Author(s):

Jessica C. Walsh ◽

Oscar Venter ◽

James E. M. Watson ◽

Richard A. Fuller ◽

Tim M. Blackburn ◽

...

Keyword(s):

Species Richness ◽

Exotic Species ◽

Native Species ◽

The Impact

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Local and landscape features constrain the trait and taxonomic diversity of urban bees

Landscape Ecology ◽

10.1007/s10980-021-01370-z ◽

2021 ◽

Author(s):

Hamutahl Cohen ◽

Monika Egerer ◽

Summer-Solstice Thomas ◽

Stacy M. Philpott

Keyword(s):

Species Richness ◽

Taxonomic Diversity ◽

Phenotypic Traits ◽

Urban Landscapes ◽

Wild Bees ◽

Landscape Features ◽

Landscape Scales ◽

Impact Of Urbanization ◽

Species Richness And Abundance ◽

The Impact

Abstract Context There is concern that urbanization threatens bees, a diverse group of economic importance. The impact of urbanization on bees is likely mediated by their phenotypic traits. Objectives We examine how urban cover and resource availability at local and landscape scales influences both species taxonomic and functional diversity in bees. Methods We used a combination of aerial netting and pan traps across six sampling periods to collect wild bees in 18 urban gardens spanning more than 125 km of the California central coast. We identified 3537 specimens to genus and, when possible, to species to obtain species richness and abundance at each site. For each species we measured a suite of bee traits, including body size, sociality, nesting location, nesting behavior, pollen-carrying structure, parasitism, and lecty. Results We found that increased garden size was positively associated with bee species richness and abundance. Somewhat counterintuitively, we found that urban cover surrounding gardens (2 km) was positively associated with bee species richness. Urban cover was also associated with the prevalence of certain bee traits, such as bees that excavate nests over those who rent, and bees with non-corbiculate structures. We suggest that urban habitats such as gardens can host a high number of bee species, but urbanization selects for species with specific traits. Conclusions These findings illustrate that local and landscape features both influence bee abundance, species richness, and the frequency of specific traits. We highlight the importance of trait-based approaches for assessing biodiversity in urban landscapes, and suggest conceptualizing urbanization as a process of habitat change rather than habitat loss.

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The effect of exotic grass Urochloa decumbens (Stapf) R.D.Webster (Poaceae) in the reduction of species richness and change of floristic composition of natural regeneration in the Floresta Nacional de Carajás, Brazil

Anais da Academia Brasileira de Ciências ◽

10.1590/0001-3765201620150121 ◽

2016 ◽

Vol 88 (suppl 1) ◽

pp. 589-597 ◽

Cited By ~ 2

Author(s):

LEANDRO V. FERREIRA ◽

PIA PAROLIN ◽

DARLEY C.L. MATOS ◽

DENISE A. CUNHA ◽

PRISCILLA P. CHAVES ◽

...

Keyword(s):

Species Richness ◽

Species Composition ◽

Natural Regeneration ◽

Floristic Composition ◽

Biodiversity Loss ◽

Life Forms ◽

Natural Habitats ◽

Urochloa Decumbens ◽

Exotic Grass ◽

The Impact

ABSTRACT The introduction of exotic species is considered as one of the major causes of biodiversity loss. The National Forest of Carajás is one of the largest mineral provinces in the world. Mining activities caused changes of the natural habitats, leaving degraded areas after the mineral exploitation. One of the mining areas within FLONA Carajás was used for the extraction of gold. In the process of exploitation, a huge depression was formed by the removal of soil which was mounded up nearby. To prevent soil erosion of these mounds, an exotic grass, Urochloa decumbens (Stapf) R.D.Webster (Poaceae) was planted. The objective of this study was to compare the impact of this non-native grass on species richness and species composition of the natural regeneration in the degraded areas. Four areas were compared, two with and two without presence of U. decumbens. In each area, twenty four 1m²/plots were established. Species richness of the regeneration areas and population sizes were significantly lower in the plots where the exotic grass was present. Our study shows that U. decumbens had a negative effect on species richness and population density, and its presence changed the species composition and distribution of life forms of the natural regeneration.

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Impacts of fire severity and cattle grazing on early plant dynamics in old-growth Araucaria-Nothofagus forests

Forest Ecosystems ◽

10.1186/s40663-019-0202-2 ◽

2019 ◽

Vol 6 (1) ◽

Cited By ~ 2

Author(s):

Paola Arroyo-Vargas ◽

Andres Fuentes-Ramírez ◽

Bart Muys ◽

Aníbal Pauchard

Keyword(s):

Species Richness ◽

Native Species ◽

Fire Severity ◽

Cattle Grazing ◽

Plant Composition ◽

Old Growth ◽

Time Since Fire ◽

The Impact ◽

Different Levels ◽

Over Time

Abstract Background Fire has historically shaped the dynamics of Araucaria araucana-Nothofagus pumilio forests in the Andean region of South America. Nevertheless, human disturbances and stronger drought events have resulted in increased occurrence and severity of wildfires. Regardless of their conservation relevance, the initial response to fire of Araucaria-Nothofagus forests has not been well documented. Through this research we tested the hypothesis that plant composition of Araucaria-Nothofagus forest after fire will initially differ in its recovery depending on fire severity, but over time, plant similarity will increase among areas with different levels of fire severity. The study was carried out in old-growth Araucaria-Nothofagus forests in south-central Chile (38°S) that were burned in 2015. We studied vegetation response to three levels of fire severity (low (LS), moderate (MS) and high (HS) severity), also including an adjacent unburned forest (UN), which were assessed one, two and three years after fire. We also evaluated the impact of cattle on plant recovery after fire. We measured species richness, abundance, plant diversity and origin of all vascular plant species. Results Species richness and plant abundance responded differently to fire severity. Time-since-fire had a significant effect on plant richness and abundance. Plant composition within LS areas was similar to UN areas, but MS and HS areas were significantly less diverse compared to UN and LS. In absence of other major disturbances, similarity in plant composition tended to increase over time across the different levels of fire severity, becoming more similar to UN. We also found a synergetic effect of cattle and fire on species richness. This interaction promotes the establishment of non-native species and limits the recovery of native species following fire. Conclusions Fire severity had a significant impact on the plant community of old-growth Araucaria-Nothofagus forests, especially in areas of high fire severity, where the native tree N. pumilio was completely absent. Nevertheless, plant communities can recover gradually, depending on fire severity, time-since-fire, and the absence of cattle grazing. Management actions should include the exclusion of cattle within fire-affected areas and afforestation with N. pumilio in areas high fire severity due to its unsuccessful recruitment after fire.

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Comparing environmental impacts of alien plants, insects and pathogens in protected riparian forests

NeoBiota ◽

10.3897/neobiota.69.71651 ◽

2021 ◽

Vol 69 ◽

pp. 1-28

Author(s):

Katharina Lapin ◽

Sven Bacher ◽

Thomas Cech ◽

Rok Damjanić ◽

Franz Essl ◽

...

Keyword(s):

Alien Species ◽

Environmental Impacts ◽

Native Species ◽

Temporal Trends ◽

Biosphere Reserve ◽

Riparian Forests ◽

Management Actions ◽

South East Europe ◽

Taxonomic Groups ◽

The Impact

The prioritization of alien species according to the magnitude of their environmental impacts has become increasingly important for the management of invasive alien species. In this study, we applied the Environmental Impact Classification of Alien Taxa (EICAT) to classify alien taxa from three different taxonomic groups to facilitate the prioritisation of management actions for the threatened riparian forests of the Mura-Drava-Danube Biosphere Reserve, South East Europe. With local experts we collated a list of 198 alien species (115 plants, 45 insects, and 38 fungi) with populations reported in southeast European forest ecosystems and included them in the EICAT. We found impact reports for 114 species. Eleven of these species caused local extinctions of a native species, 35 led to a population decrease, 51 to a reduction in performance in at least one native species and for 17 alien species no effects on individual fitness of native species were detected. Fungi had significantly highest impact and were more likely to have information on their impacts reported. Competition and parasitism were the most important impact mechanisms of alien species. This study is, to our knowledge, the first application of EICAT to all known alien species of several taxonomic groups in a protected area. The impact rankings enabled to identify taxa that generally cause high impacts and to prioritize species for the management in protected areas according to their impact magnitudes. By following a standardized impact protocol, we identified several alien species causing high impacts that do not appear on any expert-based risk list, which are relevant for policymakers. Thus, we recommend that alien species be systematically screened to identify knowledge gaps and prioritize their management with respect to spatio-temporal trends in impact magnitudes.

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