Urban parks: refuges for tropical butterflies in Southeast Asia?

Rapid economic development has accelerated urbanisation and biodiversity loss in Southeast Asia. Studies of urban ecology have suggested urban parks can be effective refuges for wildlife in temperate regions, but their effectiveness as refuges in rapidly urbanising tropical regions is understudied. We examined the species diversity of butterflies in urban parks in the Federal Territory of Kuala Lumpur and investigated the relationships between butterfly species richness and three park variables: i) park size, ii) distance from the central business district and iii) park age. Standardised butterfly sampling was conducted across different microhabitat types at each park: i) groves, ii) hedges, iii) flowerbeds and iv) unmanaged areas. We recorded 572 butterflies belonging to 60 species (97 % considered common) from five families. Although species richness was positively correlated with park size and age and negatively correlated with distance from the central business district; the correlations were weak and not statistically significant. However, species richness of host-specialist species was significantly positively correlated with park size and age. The highest species richness (65 % of observed species) was recorded in the unmanaged microhabitat. It is likely that both park planting scheme and the presence of early successional plants in unmanaged microhabitat led to highest butterfly species richness in parks that contained all four microhabitat types. Whether a diverse planting scheme and increased size and number of unmanaged areas in urban parks can improve the ability of parks to sustain populations of rare butterflies in the face of future urbanisation remains to be seen.     

Urban park area and age determine the richness of native and exotic plants in parks of a Latin American city: Santiago as a case study

Plant diversity and composition in urban parks is determined by socio-economics, environmental, and ecological drivers. These drivers give rise to urban spaces with unique compositions of flora, consisting of planted and spontaneous species. The present study aimed to determine the contribution of native and exotic species in urban parks of a Latin American city, and to assess the related role of park area, age and socio-economic status. We also evaluated administration type (public or private) and the effect of environmental factors on plant richness. We hypothesized that the composition of park vegetation differs according to urban-rural gradient. To determine flora composition, two transects (100 m long by 1–3 m wide) per park were selected in 49 parks. In each of these, we identified all the vascular plants found (woody and herbs, planted and spontaneous), which were then classified as native or exotic. We conducted ANCOVAs in order to determine the effect of five independent variables and one factor, on native and exotic plant richness. Of 550 recorded species, 16.2% were native and 83.8% exotic. Number of plant species per park varied between 42 and 146. The parks are known urban habitats containing the highest planted and spontaneously occurring exotic diversity in the city of Santiago, contrasting with other types of habitats. Likewise, parks in Santiago are habitats with low levels of planted and spontaneously occurring native diversity, compared to the parks of Europe, America North and Asia. Ours results show that park area and age affected native plant richness, while exotic plant richness was determined only by park age. We rejected all other possible drivers. Finally, according to the low frequency of native species, we propose that Santiago’s parks could be gradually reoriented towards ex-situ conservation of native plants.     

Drivers of biodiversity patterns in parks of a growing South American megacity

How urban habitats contribute to biodiversity conservation is a key challenge in a rapidly urbanising world. Urban parks can provide important habitats for native species, but previous studies are geographically biased; fast growing megacities, in particular in South America, are clearly understudied. To assess habitat functions and underlying drivers in parks of Santiago de Chile, we analysed the assemblages of wild growing plant species in two ubiquitous park habitat types (grasslands, wooded areas) in 15 parks (150 plots) along an urban-rural gradient. We first used linear contrasts to compare species richness, beta diversity and the proportion of introduced species. We then tested for the explanatory value of environmental variables operating at different spatial scales (plot, park, urban matrix). Unlike in most previous studies, biodiversity patterns were not related to the position of the parks on the urban-rural gradient. Introduced species, mostly from Europe, generally dominated both habitat types (>90 %). Socio-economic (population growth or density), but not spatial, variables were retained in most models. Maintenance intensity was most influential in predicting species assemblages, complemented by park age in wooded areas. A high proportion of European grassland species indicates a trend of homogenisation in park grassland at a cross-continental scale. We conclude that habitat functions of urban parks for native species that have been mainly demonstrated for Europe cannot be generalised to South American megacities. This highlights the need for innovative and locally appropriate conservation approaches (e.g., re-introduction of native species) to foster biodiversity functions in urban parks of South American megacities.     

Characterizing urban butterfly populations: the case for purposive point-count surveys

Developing effective butterfly monitoring strategies is key to understanding how butterflies interact with urban environments, and, in turn, to developing local conservation practices. We investigated two urban habitat types (public gardens and restored/reconstructed prairies) and compared three survey methods (Pollard transects, purposive point counts, and random point counts) to determine which was most productive for detecting butterflies and assessing family diversity. We conducted 66 butterfly surveys by using each method (198 total) from May through September in 2015 and 2016 at six sites (three public gardens and three prairies) in Ames, Ankeny and Des Moines, Iowa. All survey methods were used on 11 sampling dates at each site. Overall, we observed 2,227 butterflies representing 38 species: 1,076 in public gardens and 1,151 in prairie areas. We used a smaller data set standardized for survey effort, including 1,361 of these sightings, to compare survey methods and habitat types. Although there were no significant differences in number of butterfly sightings between the two habitats, more sightings (798) were documented by using purposive point counts when compared to Pollard transects (297) or random point counts (266) (for both comparisons, p?<?0.0001). Occupancy modeling also indicated that purposive point counts were most effective in detecting certain species of butterflies, most notably those within the Pieridae (whites, sulphurs) and Papilionidae (swallowtails). We conclude that public gardens and restored/reconstructed prairies in urban settings can provide important butterfly habitat, and that purposive point-count surveys are most effective for detecting butterflies in these relatively small-scale landscape features.

     

Urban gradients alter the diversity,specific composition and guild distribution in tropical butterfly communities

The increasing expansion of the urban environment has been considered one of the causes of biodiversity loss. Due to the decrease of the quantity and quality of habitats, this process causes the restriction of organisms to sometimes-specific microhabitats. The patterns of variation of the biodiversity along the environmental gradients, however, are still poorly understood. This study evaluated how urban gradients affect the diversity, specific composition and frequency of guild of the community of butterflies. Butterflies were collected in three transects continuously traversing the urban, rural and preserved habitats using baited traps and by active sampling. We found that the urban gradient acts as an environmental filter in the butterfly communities, reducing the richness and frequency of guilds of frugivorous butterflies, structuring the community through turnover, but without effects in the abundance. This study shows the importance of the urban gradients approach in the butterfly community and its applicability in the management of urban areas in order to include native vegetation along the gradients, aiming at increasing environmental heterogeneity, to preserve butterflies and maintain the ecosystem services and network interactions in altered landscapes.

     

Butterflies in the city: a review of urban diurnal Lepidoptera

Human migration to urban centers has resulted in diverse environmental disturbances that affect biodiversity. Although urbanization has been highlighted as one of the main drivers of biodiversity endangerment, this topic is still poorly studied in many countries. In order to establish the status quo of the ecology of butterflies in urban centers, we gathered publications focused on urban butterflies (Lepidoptera). We compiled a total of 173 studies from 37 countries and more than 110 urban areas, including published papers and theses (1956–2015). Most papers (69 %) addressed ecological topics, 14 % were focused on biological conservation, and 17 % corresponded to species lists. In summary, most studies revealed a negative impact of urbanization intensity on butterfly diversity (richness and abundance). In fact, we found studies reporting local extinctions due to urbanization, highlighting the causes related to them. The study of charismatic urban wildlife groups, such as butterflies, is a promising field, as there are still important gaps in our comprehension of the ecological patterns and processes that occur in urban areas. Undoubtedly, understanding the response of butterflies to urbanization will aid in the development of urban biodiversity management, planning, and conservation strategies worldwide, which together with knowledge of other wildlife groups and socioeconomic variables, will lead us to more sustainable, livable, and biodiverse cities.     

Legacy effect of trees in the heritage landscape of a peri-urban golf course

Negative environmental impacts of golf courses have received more attention than positive ecological contributions. We studied the mature tree communities and their legacy effect in a historical urban-fringe golf-course site in Hong Kong covering 170-ha with well-managed natural-cum-cultural landscape. Some 44.3 % of the site is covered mainly by large trees forming a mature peri-urban forest. The 94 species in 35 families offer a high species diversity exceeding local secondary and climax fengshui woodlands with notable rare and protected species. Tree species composition, richness and legacy effects brought by anthropogenic and natural factors were investigated by three habitats with varying naturalness and three golf courses with different age. Landscape zone is remarkably heterogeneous versus other microhabitats (fairway and woodland) and the heterogeneity of tree communities amongst the three courses is relatively weak. Synergistic operation of natural regeneration (natural legacy effect) and anthropogenic management (anthropogenic legacy effect) has fostered diversity accumulation. On the one hand, temporal changes in landscape fashion through a century and variations in site management have driven and maintained species diversity. On the other hand, the founder effect of inherited and cultivated species, as well as successful invasion and establishment of native species, have imposed floristic imprint and inertia on woodland habitat. The findings suggested that urban golf courses can serve as potential hotspots for biodiversity conservation within urban ecosystems.     

The influence of small urban parks characteristics on bird diversity: A case study of Petaling Jaya,Malaysia

The capacity of small urban park to serve as urban habitats are rarely explored. This study analyses the characteristics of small urban parks and their potential to support urban biodiversity and ecological functions. Nine small urban parks were studied in Malaysia in August and September 2014 using the combined field survey method of structured observation and field measurements. The measured variables were divided into three broad categories of physical characteristics, species richness and human factors. Bird species richness and abundance were used as the indicators for assessing biodiversity. Pearson correlations and multiple regressions were conducted to analyse the relationships between variables and to identify which variables had a significant effect on bird species richness and abundance. The results demonstrated that park area and vegetation variables ( e.g. the percentage of tree canopy cover, open grass/ground, native-exotic plants) are the important predictors of bird species richness and abundance. The percentage of canopy covers (negative relation) and park area (positive relation) are the best predictors of bird species richness in small urban parks. Meanwhile, the best predictors for bird abundance are the percentage of canopy covers (negative relation) and native vegetation species (positive relation). Human activities and park surroundings have a marginal effect on the presence of bird species in small parks. Based on the findings, we provide two general recommendations that could probably increase bird diversity in small urban parks: (1) the park development and management plan should incorporate a social-ecological approach that can benefit both city-dwellers and bird species, and (2) findings from the study should be used to rethink the planting design and composition of especially newly established small urban parks.     

Tales of urban conservation: <Emphasis Type="Italic">Eumaeus</Emphasis> butterflies and their threatened cycad hostplants

Urbanization has caused the local extinction of several butterfly species around the world, while others have managed to thrive in urban areas. Butterflies of the genus Eumaeus are among the most striking and colorful lycaenid butterflies in the Americas, but their neurotoxic hostplants, cycads, are a highly threatened plant group. The main threats for cycads are the loss and modification of their habitats and their removal for ornamental purposes, which in addition to their slow growth rate, make them highly vulnerable. Ornamental cycads are taken from natural habitats to urban areas, where they are playing an important role for Eumaeus reproduction. We here report two cases in which two Eumaeus species (E. childrenae, E. atala) are following and utilizing ornamental cycads to reproduce in urban areas, showing how significant urban areas can be, ecologically speaking. Aside from having enormous potential as flagship species for conservation in urban areas, these butterfly and plant species, and their interactions, shed encouraging light on the idea of putting reconciliation ecology ideas into action.     

Similar effects of residential and non-residential vegetation on bird diversity in suburban neighbourhoods

Estimating the relative importance of vegetation on residential land (gardens, yards, and street-trees) and vegetation on non-residential land (parks and other large green spaces) is important so that competing options for urban conservation planning can be prioritized. We used data from an urban breeding-bird monitoring program to compare the relative effects vegetation on residential land and vegetation on non-residential land (both the amount and type of vegetation at local and landscape scales) on bird species richness and an index of conservation value for the bird community. We then estimated the realised relative benefit of managing the amount of vegetation on these two types of land (i.e., as alternative management options for promoting biodiversity), which might be achieved within the practical limits imposed by human population density. The local effects of increasing residential and non-residential vegetation amount were similar and positive on all measures of bird species richness and conservation value. Non-residential vegetation had an additional landscape-scale influence on bird diversity that residential vegetation did not. Options for managing the amount of non-residential vegetation appear to be more limited by high human population density than for managing the amount of residential vegetation. This suggests that there may be greater realised benefits to bird diversity from managing the amount of vegetation on residential land than from the more common focus of urban planning of managing vegetation on non-residential land.     

Bird and butterfly communities associated with two types of urban riparian areas

We examined the distribution of birds and butterflies at two types of urban riparian areas in the metropolitan area of Denver, Colorado, USA. The sites consisted of relatively natural areas containing native woody vegetation, and those that had been highly modified with trees and shrubs removed and planted with lawn grass. Species richness of both butterflies and birds differed significantly between the two types of sites. Species richness, however, was not significantly correlated between birds and butterflies. Bird abundance was similar between site types but consisted of two assemblages. Brewer's blackbirds, common grackles, bank swallows, and mourning doves were abundant at wooded sites while American robins, European starlings, house sparrows, house finches, and mallards were more abundant at lawned riparian sites. Butterfly abundance was less at lawned sites. This contrast in bird and butterfly response to habitats suggests they respond to different habitats in distinct ways. Both taxon groups, however, were important discriminators between habitat types. Overall, butterfly and bird species richness was 44% less at highly modified riparian sites.     

Spontaneous plant colonization and bird visits of tropical extensive green roof

Green roofs can contribute to enrichment and conservation of urban ecology. An experimental green roof was established in humid-tropical Hong Kong to monitor over two years its spontaneous colonization by plants and bird visits. Some 94 voluntary vascular plant species from 26 families and 76 genera were established, with propagules brought mainly by birds and wind and secondarily inherited from soil seed bank. Plant species composition changed dynamically during the study period. They fall into three groups, namely dominant ruderal (herbaceous and sub-shrub) as surrogate of early-stage local grassland ecosystem succession, arboreal (trees and shrubs), and hygrophilous herb. Progressive increase in vegetation cover was accompanied by changes in species diversity and evenness. In addition, 16 bird species from 8 families and 14 genera were recorded. Ten species were residents and the six migrant species were winter visitors. Their food preference was mainly omnivore and insectivore. Winter and the second year encountered higher species richness, diversity, and evenness. Most vegetation parameters correlated positively with avian community indexes, signifying provision of sustenance by green-roof ecosystem to birds. Vegetation coverage correlated negatively with avian abundance, due to shunning by the abundant ground-foraging Tree Sparrow. Both local common ruderal plant species and common urban bird species can successfully establish and reproduce on the extensive green roof, confirming potentials for urban ecology and biodiversity enhancement and conservation even in densely-developed urban areas. The successful nurturing of naturalistic green roof offers new opportunities for green roof design that deviates from the predominant cultivated-horticultural approach.     

Classes of protection in urban forest fragments are effectiveless in structuring butterfly assemblages: landscape and forest structure are far better predictors

Urbanization is a major cause of biodiversity loss and disconnection between people and nature. For this reason, the creation and maintenance of green areas as part of the urban landscape is a common practice in cities around the world. These green areas are generally a result of particular public policies regarding how these areas can be accessed, maintained, and how they are connected to other natural fragments in the city. In an effort to investigate aspects of the ecology of such green areas of the city of Curitiba, southern Brazil, the present study measured distinct parameters of the structure of butterfly assemblages from 19 forest fragments of distinct classes of protection, testing the influence of different policies (protection category) on butterfly assemblages. Comparatively, we also tested the predictive power of landscape variables (at distinct scales) and fragment quality (e.g. diameter at breast height, density of vegetation) using Generalized Linear Models (GLMs). Overall, 14,596 individuals belonging to 412 butterfly species were recorded, but values of species diversity and composition are very heterogeneous, indicating that the protection categories do not significantly interfere with the structure of the butterfly assemblages. More important than the protection category is the forest fragment quality and landscape connectivity. Our models showed that degraded fragments tend to present a specific butterfly composition, whereas the more urbanized landscape have poor butterfly species richness. These results reinforce the importance of implementing public policies that prioritize the conservation of the quality of forest fragments in every class of protection, as well as the conservation of forest fragments throughout the urban landscape.

     

Seasonal dynamics of bird communities in urban forests of a Mediterranean city (Montpellier,Southern France)

We evaluated the richness, composition and abundance of bird communities in three urban forests of Mediterranean France during winter and spring. The urban forests differed in size, composition, structure, age of vegetation, and location relative to the city centre. Estimated species richness across all three urban forest parks was 45 species. Twenty six (26) species were recorded in both winter and spring, whereas ten species were recorded only in spring, and six were recorded only in winter. Distribution, turnover, and type of bird foraging guild were related to characteristics of each urban forest and season. During spring migration, more species were recorded in sampling units (250?×?250 m) within the largest and most natural urban forest located in the outskirts of Montpellier, whereas during winter, more species were recorded in the most urbanized park (i.e., a botanical garden dominated by exotic vegetation), which was located in the city centre. Insectivorous birds were more abundant in winter, whereas seedeaters associated with wooded habitats were recorded more frequently in spring. Our results suggested that different kinds of urban forests are important modulators of urban bird communities and they are necessary to maintain the diversity of migratory and resident birds as well as increasing the environmental quality of urban areas.     

Reducing management intensity and isolation as promising tools to enhance ground-dwelling arthropod diversity in urban grasslands

Urbanisation is a growing global phenomenon having multiple ecological consequences. However, the effects of urbanisation on biodiversity remain ambiguous, and some evidence exists that cities provide valuable secondary habitats for many species, possibly mitigating regional biodiversity loss. Therefore, the value of urban sites for biodiversity depends on local habitat conditions and the configuration of the surrounding landscape. We aimed to disentangle the effects of local habitat parameters (management, plant diversity) and urban matrix variables (urbanisation, isolation) on carabid beetle and spider diversity and traits in informal urban green spaces in Berlin, Germany. Habitat management and isolation were the most important influences on carabid beetle and spider species and trait compositions. Spider communities of irregular managed sites contained 2.5 times more species of conservation concern than extensive (regular) managed sites. Moreover, irregular managed sites contained larger species (both for carabid beetles and spiders) and affected the hunting mode of spiders. Isolated sites tended to have lower spider species richness and number of spider species of conservation concern. Moreover, isolated sites were characterised by small, mobile and herbivorous carabid beetles. In contrast, urbanisation and local plant diversity had no effect on carabid beetles and spiders. We conclude that urban grasslands within residential areas – even if not targeted for conservation plans – can provide important habitats for conserving biodiversity, including species of conservation concern. Reducing the intensity of habitat management and increasing the connectivity of urban grassland sites can promote diverse arthropod communities and should therefore be considered in urban planning.     

Composition and conservation value of bird assemblages of urban ‘habitat islands’: Do pedestrian traffic and landscape variables exert an influence?

Urban forest fragments can potentially be ‘habitat islands’ for native birds, but pedestrian traffic could influence the composition and conservation value of their bird assemblages by reducing the representation of disturbance-sensitive species. Winter bird assemblages and pedestrian traffic rates were documented in twelve forested parks in suburban Melbourne, Australia. Native birds comprised 87% of sightings, but two exotic species were common. Bird species' distribution among the parks was significantly nested. However, park rank orders for bird assemblage nestedness and mean pedestrian traffic rate were not correlated and only one species' distribution was nested with respect to this variable. The observed correlation between park area and bird assemblage nestedness may have been partly due to passive sampling. Degree of isolation of parks influenced nestedness less than park area. Forested parks provided habitat for species that occur at intermediate to low densities in other suburban habitats and for ecological specialists otherwise rare in suburbia. Larger parks contained more species than, and many of the native species found in, smaller parks. However, smaller parks each had 25% of the native bird species inhabiting the suite of fragments and thus had both aesthetic value and some potential to enhance city-dwellers' awareness about biodiversity conservation.     

Impacts of urbanisation on the native avifauna of Perth, Western Australia

Urban development either eliminates, or severely fragments, native vegetation, and therefore alters the distribution and abundance of species that depend on it for habitat. We assessed the impact of urban development on bird communities at 121 sites in and around Perth, Western Australia. Based on data from community surveys, at least 83 % of 65 landbirds were found to be dependent, in some way, on the presence of native vegetation. For three groups of species defined by specific patterns of habitat use (bushland birds), there were sufficient data to show that species occurrences declined as the landscape changed from variegated to fragmented to relictual, according to the percentage of vegetation cover remaining. For three other groups (urban birds) species occurrences were either unrelated to the amount of vegetation cover, or increased as vegetation cover declined. In order to maximise the chances of retaining avian diversity when planning for broad-scale changes in land-use (i.e. clearing native vegetation for housing or industrial development), land planners should aim for a mosaic of variegated urban landscapes (>60 % vegetation retention) set amongst the fragmented and relictual urban landscapes (<60 % vegetation retention) that are characteristic of most cities and their suburbs. Management actions for conserving remnant biota within fragmented urban landscapes should concentrate on maintaining the integrity and quality of remnant native vegetation, and aim at building awareness among the general public of the conservation value of remnant native vegetation.     

Avian diversity in a suburban park system: current conditions and strategies for dealing with anticipated change

A growing trend towards increased urbanization emphasizes the role of suburban parks in wildlife conservation. Spatial planning aimed at maintaining biological diversity and functionality must consider how changes at landscape and more local scales will influence the biotic structure of urban areas. From May 2006 to July 2010, bird surveys were conducted in three metropolitan parks in Cleveland, Ohio, USA. Surveys were conducted with the goal of examining the effect of vegetation structure and adjacent land cover on the distribution and species richness of breeding birds within this park system. A total of 65 species were recorded throughout the study area. Avian species richness was linked to several habitat metrics, measured at both the local and landscape scale. Generally, species richness was highest at locations characterized by moderate forest cover. The proportion of canopy cover at survey sites related negatively to species richness and the density of understory vegetation showed a positive relationship with species diversity. Despite the influence of these three metrics, sensitivity analysis indicates that the density of understory vegetation is the most significant correlate to avian diversity within this suburban park system. Management actions aimed at providing habitat for the greatest diversity of breeding songbirds within the study area should allow for moderate canopy cover while retaining or improving the structural complexity of understory vegetatation.     

Nested patterns in urban butterfly species assemblages: respective roles of plot management,park layout and landscape features

Increasing numbers of cities are currently developing sustainable policies aimed at promoting urban biodiversity and ecological dynamics through the planning of green networks and the implementation of more sustainable management practices. These human activities can strongly influence environmental factors on which the organization of ecological communities at different scales depends. Thus, it is of fundamental importance to understand the relative impact of local management, green space design and landscape features on the distribution and the abundance of species in urban areas. On the basis of 2 years of butterfly surveys in urban public parks within an extensive Mediterranean metropolitan area, Marseille (South-East France), the aim of this paper is to provide a better understanding of the effect of these three environmental scales (plot, park, landscape) on the composition and organization of species assemblages. Using variation partitioning and nestedness analysis on ecological data aggregated at plot-level and park-level respectively, we demonstrate the preponderant effect of landscape scale features on urban butterfly assemblages. Our results also highlight an important co-variation of plot management, park layout and urban landscape features, in their interaction with the community structure of urban butterflies. Although there is no significant species-area relationship, significantly nested patterns arise in species composition. Selective colonization appears as a driving force constraining the constitution of species assemblages within the city. However, a prospective study on adjacent more natural areas suggests that biotic limitations, interspecific competition and habitat filtering may play an important role if a larger portion of the urbanization gradient is explored, which remains to be investigated.     

Urban open spaces from a dispersal perspective: lessons from an individual-based model approach to assess the effects of landscape patterns on the viability of wildlife populations

Green areas drawn on a city plan represent open spaces that have different meanings for humans and wildlife. Diverse kinds of green may influence species viability in urban environments. It is necessary to understand what those areas mean for wildlife populations and how land-use changes affect habitats and movements for making scientifically defensible planning and design decisions. My objective was to demonstrate how open space and urban development patterns affect the viability of wildlife populations in urbanizing landscapes from a movements perspective. Eight scenarios for 2060 for an urbanizing area near Portland, Oregon combined four open space (none, corridors, parks, and network) with two urban development patterns (compact and dispersed). Dispersal model HexSim simulated three target species – Red-legged frog (Rana aurora aurora), Western meadowlark (Sturnella neclecta) and Douglas squirrel (Tamasciurus douglasii) – movements on those scenarios to compare and contrast sustained populations to the ca. 2010 baseline landscape. Network scenarios presented the largest number of frog breeders. Greenway scenarios showed the largest populations of squirrels. Park and network scenarios sustained viable populations of meadowlarks, but park scenarios performed best. Compact development scenarios performed best for most indicators, while dispersed development scenarios performed better for meadowlarks. Network scenarios performed best when considering the collective of species. Networks presented more diverse habitats, sustaining higher diversity of species. For plans to sustain more species, more comprehensive and diverse habitats must be promoted, otherwise trade-offs should be expected – like the extinction of meadowlarks in greenway scenarios.