The effects of habitat on the distribution of urban ruderal vegetation

Ruderal habitats consist mostly of neutrophile plants that grow on specific areas such as remnant areas, ruins, and wall sides. The plants hold an important place in urban ecology due to their resistance to environmental conditions and anthropogenic impacts. Considering the past 20-year period, today’s rural areas will soon become urban areas in most parts of the world. Thus, this study will contribute to the phytoecological and phytosociological studies that will elaborately examine urban ruderal habitats in near future. The study was carried out in 30 different locations in five different land use types in Trabzon, Turkey. It aims to determine the ruderal vegetation diversity and the effect of habitat on ruderal vegetation. The results of the study revealed 83 species across 33 families. Despite the species diversity of the samples from the roadsides differed from that of other regions, the ruderal vegetation was distributed homogeneously, leading to the conclusion that habitat did not affect vegetation.


Introduction
Humankind has a global force that can rapidly transform the environments it lives in.The transformation occurs through the anthropogenic impact and, including biodiversity, affects all environments and ecosystems people live in including biodiversity (Benítez-López et al. 2019;Hu et al. 2021;Winkler et al. 2021).The pressure on natural resources is growing due to urbanization and industrialization.Natural resources are rapidly deteriorating due to misuse, which adds to the pressure on remaining natural resources (Keesstra et al. 2018;Visser et al. 2019).With the decline of open green spaces, awareness of the importance of nature and the value of the management of natural resources is rapidly increasing (Eroğlu et al. 2018;Atasoy and Çorbacı 2018).
The plant cover that adapted to changing living conditions due to anthropogenic impact on urban landscapes is called synanthropic vegetation (Dihkan 2020).Different habitats around the world harbor various species and use the relationship between the species through the characteristics they encompass (Meral et al. 2018).As a type of synanthropic vegetation, ruderal vegetation adapts to destroyed and resource-poor areas (Akdeniz and Şafak 2015).This type of vegetation is the most important component of urban green areas and distributes widely in and around cities without any need for financial costs (Guo et al. 2018).Ruderal habitats grow on specific areas such as remnants, ruins, and wall sides, and they are mostly neutrophilic (Altay and Karahan 2017;Yalçınalp and Meral 2019).The plants distribute in intervened areas with no competition, in other words, non-stagnant habitats in the early succession phases of vegetation.They especially prefer regions with high precipitation and moisture (Karaköse et al. 2018).The studies on urban vegetation have revealed that the distribution of ruderal plants is correlated with two parameters comprising soil water content and the frequency and density of human intervention (Dana et al. 2002;Sarah and Zhevelev 2007;Chen et al. 2014).
The habitat change due to rapid urbanization is a key factor and plays an important role in the distribution of ruderal plants.The species that have specific properties to certain habitats are lost due to selection as a result of different habitat losses while natural species persevere in anthropogenic and disrupted habitats.Ruderal species have certain properties that allow survival in anthropogenic habitats such as pollination, wind-driven distribution, aesthetic appeal, and tolerance to water stress and, thus, can colonize the urban landscapes.They have great importance in urban areas in terms of biodiversity (Ohsawa et al. 1988;Dihkan 2020).
Little is known about these plants that characterize urban areas in which the greater portion of the world's population resides.Thus, there is a great need for studies on ruderal plants to better understand cities (Yalçınalp et al. 2017;Yalçınalp and Meral 2019).Ruderal plants are ideal for examining the effects of urbanization on ecosystems and reacting to these effects (Cilliers and Bredenkamp 1999;Chen et al. 2014).
In light of this view, this research was commenced in hopes of reaching interesting results about these special habitats that are specific to cities.In the study, 30 different areas among 5 land use types in Trabzon, Turkey, were selected and plant samples were identified during the period between March and August to examine the effects of habitat and different land use types on ruderal plant species.The results revealed that ruderal plants were distributed homogeneously and were not affected by different land conditions and land uses, but the species in roadsides were different from those of other regions in terms of diversity.

Materials and methods
Study area -The study was carried out in the city center of Trabzon, Turkey (Fig. 1).The spontaneously growing plant cover in areas that were randomly selected among five different land use areas in Trabzon city center was the focus of the study.The city is in the A8 region of the flora in Turkey and has a mean annual temperature of 14.8 °C and mean annual precipitation of 828.9 mm (Yalcinalp and Meral 2017;MGM 2022).
-Considered as a habitat character, urban areas are relatively easy to identify when compared to similar other habitat characters.While many factors like climate and location can affect plant diversity all over the world, temperature, precipitation, UV exposure, organic nutrient access, salt and solutions, detergent used for cleaning in urban areas make plant life a bit harder and more similar to each other's within urban ecosystems.Plus, these areas are exposed to many compelling factors such as substances, direct pressure from people, etc.This does not mean that the vegetation in urban areas does not differ across the globe.However, it is relatively possible to say that the vegetation in urban areas is more generalizing in terms of character, species diversity and species when compared to other natural ecosystems.When the previous studies are examined, it is one of the proofs of this subject that researches on urban wall vegetation and roof vegetation make references and comparisons to urban studies done before them, regardless of their geographies.Therefore, the fact that these and similar studies were carried out in a typical urban ecosystem is more important than the city in which they were made.There are two main reasons for this: 1 The data to be obtained from such studies conducted around the world will contribute greatly to the formation of a common database and to the understanding of urban ecosystems and 2 urban ecosystems create common coercive conditions for many of which we can use the word "unfortunately" and therefore they speak a common language all over the world.This research, conducted in Trabzon, a typical city located in the temperate maritime climate zone in the Northeast of Turkey, will be an important indicator for many areas with similar characteristics.Therefore, the research area can be considered as an important reference for all coastal cities in the temperate climate zone of Europe.The fact that the existence of ruderal plants is known to increase the belief that degraded habitats can be rehabilitated further increases this importance (Randelovic and Jovanovic 2023).Understanding of ruderal plants is also an important step in terms of protecting natural habitats.
-For example, there are studies showing that trekking trails facilitate the spread of ruderal species to natural ecosystems (Liedtke et al. 2020).Long-term data on the distribution of ruderal plants are seriously needed in order to fully understand the studies on the spread of some of the plant species while disappearing, especially due to climate change (Wiegmans et al. 2023).

Sample
Thirty different areas among the five land use types (between structures, remnant areas, abandoned areas, wall ends, and roadsides) were selected and plant samples were collected during the period between March and August (Fig. 2).
The collection of the plant samples was carried out in all selected areas without any limitation of borders.The plants were pressed and dried and prepared for identification.The identification of the plants was carried out in the laboratories of the Karadeniz Technical University Faculty of Forestry Herbarium using a stereomicroscope.

Construction of the databases
To determine the environmental conditions that affect ruderal vegetation, surface area, plant coverage of the areas, mean sunshine duration, land use, use status, solar radiation index, altitude, aspect, geological formation, and the total number of species during the vegetation period were determined and included in the study.Table 1 shows the data collection method and classification types.

Statistical analyses
The analyses were carried out using the JMP 7 package program.Correlation analysis was employed to determine the relationship between species diversity and the datasets included in the study.The species diversity was the first variable x , while surface area, plant coverage, mean sunshine duration, land use, use status, solar radiation, altitude, aspect, slope, and geological formation constituted the second variable set y .A scatterplot matrix table was prepared to visualize the results of the statistical analyses.
The bivariate analysis was carried out to reveal the correlation between the species diversity and data sets and determine the empirical relationship between the two variables.

Calculation of the diversity index (Shannon-Wiener)
The following equation is used in the calculation of the Shannon-Wiener Index (1) (Shannon 1948).
p i represents the abundance ratio of each species in a sam- ple population.In other words, the value of p i is the ratio (1) between the abundance value of one species (n) and the total abundance values (N) (Pielou 1984).
After the calculation of diversity using the Shannon-Wiener index, (2) is used to determine the evenness  value (E) , which is described as the balanced distribution of species in a sample population (Pielou 1966).
The term H max = lnS and the (E) value ranges between 0 and 1 .The value 1 indicates complete evenness meaning a balanced distribution between the species, while the value of 0 indicates complete unevenness.
The t-test is recommended as an ideal method to test the significance of the difference between two populations after calculating their species diversity using the Shannon-Wiener index (H�) in (3) (Hutcheson 1970).
Here, H′ 1 and H′ 2 are the Shannon-Wiener diversity val- ues of the sample populations and VarH′ 1 and VarH′ 2 are the variance values of the populations and calculated using (4).
The term S represents the species richness.The stand- ard deviation value (sd) is needed to test the significance (*p ≤ 0.05 or **p ≤ 0.01 ) of the difference with respect to the t value, which is calculated using (5) (Özkan et al. 2020).
The terms N 1 and N 2 represent the abundance values or the total number of individuals in the primary and secondary populations, respectively.

Results
Plant species -The results revealed that 84 species from 33 families were distributed in the study area.A total of 189 samples from 45 species in areas between structures, 129 samples from 41 species in remnant areas, 72 samples from 31 species in abandoned areas, and 318 samples from 55 species on roadsides were identified (Table 2). (2) -The spatial distribution and distribution areas of diversity were determined and mapped (Fig. 3).The results revealed that the families that were represented by more than three species included Asteraceae (14), Poaceae (11) Brassicaceae (6), Apiaceae (4), Lamiaceae (4), and Polygonaceae (4).In the same vein, Yalçınalp and Meral (2019) determined that the families that were represented by more than three species were Asteraceae (7) and Rosaceae (4).
-The 10 species that have the greatest number of samples with regard to the identification of the ruderal plants that were collected from the study area were Parietaria Judaica L. ( 30 17), Amaranthus chlorostachys Wild.( 16), and Phytolacca americana L. ( 16).Except for La.pur L. and Smy.ol L., all species were identified in all areas while La.pur L. was only identified in areas between structures and Smy.ol L. was identified on roadsides.

Statistical analyses
Ruderal plants are the plant cover that is affected by various human activities and growth of which directly depends on this type of activities (Medvecká et al. 2009).Anthropogenic factors play a key role in the formation, survival, distribution, diversity, and dynamics of the plant cover (Jarić et al. 2011).
There was no correlation between the number of species and field parameters since ruderal plants show homogenous distribution (Fig. 4).
Bivariate analyses were carried out to determine the effects of the relevant factors on the number of species in the study area in which there was no correlation (Fig. 5).
Bivariate analyses revealed that the number of species was not directly or inversely proportionate to the land conditions and the number of species was distributed randomly.

Species diversity
The Shannon-Wiener index was used to examine the differences between species diversity.The results revealed that the plants that were collected from remnants, between structures, abandoned areas, and wall ends did not differ.However, the species diversity of the roadsides was different from that of other areas (Table 3).
The results of the study showed that the ruderal plants distributed homogeneously, and different land conditions and uses did not affect the number of species, but the species from the roadsides differed from other species in terms of diversity.This difference was attributed to the indirect contribution of roads to plant growth conditions through their microhabitat diversity.Roads are usually lit due to the clearance of roads.That said, they are mostly impermeable surfaces and roadsides are the closest regions they can infiltrate the water on their surfaces.Especially during salting and shoveling processes, salt-tolerant plants can grow on roadsides due to salty water splashing on the roadsides.

Discussion
Similarly, in their study on the wall vegetation in Trabzon, Yalcinalp and Meral (2017) found that the most common species were Par.jud L., Sonc.olL., and Mer.an L..This study also revealed that these species were distributed not only on walls but also on different habitat types.
In their study on roof vegetation in Trabzon, Yalcinalp et al. (2017) only found that Con.can L. distribution was similar to that in this study.This indicates that the species better grow in shady and semi-shady areas since rooftops are usually shaded by long trees and the species is the only common species between the two studies.Ruderal plants react to the heterogeneity of urban habitats and adapt to changing habitats by changing their morphologies, physiologies, and behaviors due to their high sensitivity and flexibility (Cilliers and Bredenkamp 2000;Chen et al. 2014).Areas with ruderal strategy comprise various plant forms such as competitive species, perennial plants, bushes, and trees while including Fig. 3 The number of species in the study area a homogenous group of plants that are very similar to each other in terms of life history and ecology (Grime 1977).
Ruderal plants emerge due to vulnerable plant populations with poor biodiversity as invasive taxa (Rendeková et al. 2018).Although considered damaging to biodiversity for being invasive, some studies have argued that ruderal plants served ecosystems in that they reduce the impact of urban heat islands, provide living spaces for wildlife, and reduce surface flow and carbon emission (Robinson and Lundholm 2012).
Finally, as the places where the circulation of anthropogenic impact is naturally maximum, roads are special areas in terms of city and human interaction.Urban areas have the potential to receive more sunlight than the average.Furthermore, water collected on impermeable surfaces is not subjected to evaporation but is transferred to surface runoffs and transferred to cracks on the sides of the roads or to soil areas.This significantly reduces the potential water stress to plants.Pedestrian and vehicular activity also increases seed transport.The increase in ruderal plants in direct proportion to human activity can be interpreted as an indication of the possible increase in diversity (Ullmann et al. 1995).
The anthropogenic impact on cities is growing due to increasing population and migration density.Thus, the importance of studies on cities grows with each passing day.Ruderal plants are among the most important concepts that require further examination for cities that are daily affected by various parameters in terms of increasing the number of green areas, determining biodiversity, and removing the plants from areas where they can be harmful.
Although researches on the urban ecosystem sometimes focus on certain characters such as wall surfaces, cracks, and roof vegetation, there are also studies that see the urban ecosystem as a whole.Therefore, while considering the areas with different characters in the urban ecosystem separately, it would probably make it possible to search for meaningful differences and similarities between them; otherwise, it would have dealt with the city as a whole, as in many previous studies.In this sense, as a result of the observations made in the research area, ruderal plants were preferred to be considered in different characters that are likely to cause differences in parameters such as light, accessible water, nutrients, UV exposure time, and intensity, while has already been proven that the effects of nutrients on ruderal plant development are high, especially during growth periods (ATIF 2).
Today, more emphasis is put on sustainability and the biological cycle in cities is threatened due to the constant covering of green areas with hard upholstery materials and the use of imported plants that are foreign to the region Fig. 6 The number of species in the sample areas by months in landscape architecture.Instead of species that require great manufacturing and maintenance costs, ruderal plants that are adapted to city life, intense anthropogenic impact, and heavy metal pollution can be integrated into landscape projects, which will contribute to the reduction of both maintenance and manufacturing costs.
The results for the plant samples that were collected during the period between March and August showed that the species were present in each month and the number of different species in the areas was never under three species (Fig. 6).
However, since ruderal plants grow in a limited number of areas, they showed homogenous distribution and there was no statistically significant relationship between different conditions and the number of species in each area.
Today, natural and cultural resources are rapidly consumed or, at least, subject to unsustainable approaches, and the products of landscape architecture are expected to prevent this problem.However, concerns for exoticness in studies in city parks, city squares, and streets overshadow this function.Ruderal plants with great potential such as carbon sequestration, infiltration through the reduction of rainwater and increasing soil permeability, feed production for wildlife, nesting, and contribution to the agricultural economy by helping the feeding of bees, bugs, and flies through pollination are especially removed and "combated" against by subjecting to chemicals.These unfortunate plants are sold short for not being pretty enough despite their ecological and economic contribution to the urban landscape and their place is usually handed to exotic, sterile, and potentially invasive species.Then, ruderal plants try to take back their natural habitats, which brings along costs for many local governments, environmental pollution due to the use of chemicals, serious labor loss, and a meaningless cost for the used plants.Moreover, this maintenance cost renders landscape architecture the first expendable cost item in the eyes of local governments in periods in which the world economy, which naturally fluctuates, gets worse.Some argue that ruderal plants are invasive plants that emerge due to anthropogenic impact (Guo et al. 2018).However, the plants that are used in landscape architecture are considerably exotic, harbor species that pose the same threat, and require a great amount of maintenance in geographical locations that are ecologically inappropriate.Moreover, ruderal plants are found in habitats that are ecologically problematic and densely contacted by humans.In other words, rather than invading a space, ruderal plants grow where other plants cannot grow.Many studies on the determination of habitat characteristics are needed to give these plants, which minimize plant supply and maintenance costs, greatly contribute to cities by fulfilling ecological functions, and aesthetically match other plants when appropriately composited, their rightful place.The use of these plants will contribute to the ecological, economic, and sociological availability of landscape architecture worldwide.The inclusion of ruderal plants in designs will also add to the reduction of maintenance costs, long-term protection of plant compositions, and shifting the time, labor, and economic sources for plant materials toward sustainability approaches.
The presence of ruderal plants in landscape performance analysis, which has become one of the most important components of landscape architecture, means less maintenance and more ecological benefits.It is evident that using ruderal plants in plant designs will contribute to reducing the carbon footprint of industrial plants, which require significant energy expenditures in their production, and this will be a solid support in the combat against global climate change.Therefore, determining the phenological and ecological characteristics of plants that are used extensively on a global scale and introducing ruderal plants to the market with incentives will be a potentially important approach in this manner.

Table 3
Calculation results for Shannon-Wiener diversity indexBold values defines the significant differences were found only in the parameters