Home range and habitat use of feral cats in an urban mosaic in Pietermaritzburg,KwaZulu-Natal,South Africa

Feral cats (Felis catus) are one of the world’s worst invasive species with continuing expanding populations, particularly in urban areas. Effects of anthropogenic changing land-use, especially urbanisation, can alter distribution and behaviour of feral cats. Additionally, resource availability can influence home range and habitat use. Therefore, we investigated home range and habitat use of feral cats (n?=?11) in an urban mosaic with varying degrees of urbanisation and green spaces in Pietermaritzburg, KwaZulu-Natal, South Africa. Using global positioning cellular trackers, individual feral cats were followed for a minimum of six months. Minimum convex polygons (MCP) and kernel density estimates (KDE) were used to determine their home range, core area size, and habitat use. Mean home range (± SE) for feral cats was relatively small (95% MCP 6.2?±?4.52 ha) with no significant difference between male and female home ranges, nor core areas. There was individual variation in home ranges despite supplemental feeding in the urban mosaic. Generally supplemental resources were the primary driver of feral cat home ranges where these feeding sites were within the core areas of individuals. However, the ecological consequences of feeding feral cats can increase their survival, and reduce their home ranges and movement as found in other studies.     

Can a habitat specialist survive urbanization? the case of the viscacha (Lagidium viscacia,Chinchillidae)

Urban growth is a strong driver of habitat degradation and loss. In spite of that, a surprising diversity of native species may survive in urban areas. In the La Paz, Bolivia metropolitan area and surroundings, local populations of “viscachas” (Lagidium viscacia) currently survive in small, isolated habitat patches. We assessed 13 study sites in 1999, 2003, and 2007 to document the effects of urban growth on L. viscacia habitats. Degree of disturbance at the study sites increased more between 1999 and 2003 than it did between 2003 and 2007 due to patterns of urban expansion. Using satellite imagery we determined that the urban area increased 566 ha (from 1987 to 2001) mostly due to southward urban area expansion down the valley where the best viscacha habitats were located. Occupied patch area decreased 74 % between 1999 and 2007, accompanied by significant increases in patch edge-to-area ratios. Currently L. viscacia populations in La Paz are experiencing a habitat attrition process. If a current urban expansion plan for La Paz is approved, about 75 % of the remaining habitat may be lost to urban development in a short time, compromising the future viability of this species in the metropolitan area and surroundings. Environmental regulations to control urban growth of the La Paz metropolitan area are urgently required and constitute the only hope for the survival of L. viscacia in the city.     

Annual and seasonal habitat use of Columbian black-tailed deer in urban Vancouver, Washington

We investigated habitat use of Columbian black-tailed deer in urban Vancouver, Clark County, Washington, at 3 spatial scales: (1) placement of the annual home range within the landscape mosaic, (2) annual and seasonal locations of deer within the annual home range, and (3) short-term use of critical habitats (fawning areas) within seasonal ranges. Annual home range sizes of deer were 162 ha (SD = 133; 95% minimum convex polygon; MCP) and 266 ha (SD = 228; 95% adaptive kernel; AK) for does, and 756 ha (SD = 290; MCP) and 1,235 ha (SD = 382; AK) for bucks. Home range composition of does did not differ from the study area; home ranges of bucks contained more Natural ecological land-use cover types (ELUs) than did the study area. Within home ranges, both does and bucks used Natural ELUs more often than expected by their occurrence in the home range, both annually and seasonally. During the fawning season, does were also found in Natural ELUs more often than expected. Clark County-designated habitat corridors differed from both the study area and deer home ranges in habitat composition, primarily by containing more Natural and other undeveloped ELUs. Deer were located in habitat corridors more than expected. Deer in urban areas appear to use undeveloped habitat types for security. Management that maintains Natural ELUs, such as establishment of wildlife corridors, can provide important habitat components for black-tailed deer in urban habitats.     

Influence of urban landscape structure on bird fauna: a case study across seasons in the city of Valencia (Spain)

Studies on bird fauna of urban environments have had a long history, but the potential of studies mapping the distribution of birds in cities probably has not fully developed. The bird fauna of the municipality of Valencia (Spain) was studied to determine the influence of urbanization on bird species richness and abundance. Birds were censused during winter and the breeding season of years 1997–1998 in 197 squares measuring 49 ha each from a rural and an urbanized area. Across seasons the number of species decreased around 40% in the city compared with the rural landscape surrounding it. Such pattern could be attributed to the low number of farmland species capable to use the habitats inside the city, and the limited ability of urban parks in attracting woodland species. In the urban landscape, the influence of the dimensions and spatial arrangement of habitat patches was outweighed by the amount of each habitat per square. Bird richness and the abundance of most species were negatively related with the amount of built-up habitat per square and positively with the amount of urban parks, and of habitat diversity. Conversely, bird fauna was largely independent of mean park size per square especially during winter, indicating that at the landscape scale even small patches of habitat could play an ecological role. Conservation of urban bird diversity could benefit of two complementary strategies: (i) the protection of the surrounding rural landscape from urban development; (ii) habitat enhancement within the city. Particularly, a proper design and habitat management of urban parks could improve their suitability for urban bird fauna.     

Urban predator–prey association: coyote and deer distributions in the Chicago metropolitan area

We examined how predator or prey presence, as well as local and landscape factors, influence the distribution of coyotes (Canis latrans) and white-tailed deer (Odocoileus virginianus) in the Chicago metropolitan area. We collected data for 2 years at 93 study sites along 3 transects of urbanization using motion-triggered cameras. Our primary objective was to determine the relationship among coyote and deer spatial and temporal distribution, habitat characteristics, and human activity using multi-season patch occupancy models. Coyote occupancy was most strongly linked to rates of site visitation by humans and dogs, and was more likely farther from the urban center, with coyote colonization of sites inversely related to road density, housing density, and human and dog site visitation. Deer more frequently occupied sites with high canopy cover near water sources and colonized smaller sites with reduced housing density and human and dog presence. Expected predator–prey dynamics were altered in this highly urban system. Though we predicted deer would avoid coyotes on the landscape based on an “ecology of fear” framework, deer and coyote occupancy showed a strong positive association. We suggest that a scarcity of quality habitat in urban areas may cause the species to co-occupy habitat despite potential fawn predation. Modifying human foot traffic in green spaces may represent a useful tool for management and conservation of large urban mammals.     

Risk of bird predation and defoliating insect abundance are greater in urban forest fragments than street trees

Predation by natural enemies is important for regulating herbivore abundance and herbivory. Theory predicts that complex habitats support more natural enemies, which exert top-down control over arthropods and therefore can reduce herbivory. However, it is unclear if theory developed in other more natural systems similarly apply to predation by vertebrate and invertebrate natural enemies across urban habitats of varying complexity. We used plasticine caterpillar models to assess risk of predation by birds and insects, collected leaf-feeding arthropods, and measured herbivory in willow oak trees (Quercus phellos) in two seasons to determine how predation influenced herbivory across urban forest fragments, street trees planted near forest fragments, and downtown street trees. Predation attempts by birds and abundance of chewing folivores were greater on trees growing in urban forest fragments than downtown street trees. Bird predation attempts and herbivory levels were inconsistent for near-forest trees. Predation attempts by arthropods did not statistically vary among the three urban tree habitats. Contrary to expectations based on theory, chewing folivore abundance and herbivory were generally highest on trees growing in urban forests, the most complex habitat we studied, and the habitat where risk of bird predation was greatest. We suggest that urban forest fragments provide better habitat than other urban landscapes for both urban birds and chewing folivores by having greater habitat complexity. Therefore, basal resources, such as availability of suitable habitat, mediate top-down effects on herbivores in cities.

     

Predation of artificial bird nests in suburban gardens of KwaZulu-Natal,South Africa

As urbanization increases, the identification of nest predators becomes important for avian conservation and management of urban wildlife communities. We investigated bird nest predation using artificial nests in urban areas of the KwaZulu-Natal (KZN) Province of South Africa. From June 2013 through February 2014 we installed seventy-five artificial nests in 25 suburban gardens in the Ethekwini and Msunduzi municipalities of KZN. Euplectes spp. nests were used and baited with two quail-sized, hand-made, silicon eggs. These were placed in residential gardens and monitored by camera traps for 2-weeks in winter, spring and summer respectively. Generally bird nesting occurs throughout the year in KZN’s subtropical climate, with some avoidance during the autumn season. Therefore, experiments were not conducted during autumn, as fresh nests were not available for use. Overall the rate of predation on artificial nests was 25 % (n = 19), with vervet monkeys Ceropithecus aethiops pygerythrus predating 20 % (n = 17) of the nests while domestic cats Felis catus predated 3 % (n = 2) of nests. Nest predation was significantly higher in the winter season, with 79 % of depredations occurring in winter (n = 15), 16 % in spring (n = 3) and 5 % in summer (n = 1), and in areas with less canopy cover. Our results suggest that vervet monkeys may have a negative impact on nesting birds in urban environments, however, in order to assess the rate of predation experiments on natural nests coupled with information on fledgling success is deemed necessary to investigate avian population declines.     

Factors influencing expanded use of urban marine habitats by foraging wading birds

Urban marine habitats are often utilized by wildlife for foraging and other activities despite surrounding anthropogenic impact or disturbance. However little is known of the ecological factors that determine habitat value of these and other remnant natural habitats. We examined the preferential use of urban marine habitats in a northeast US estuary to try to elucidate the factors driving enhanced foraging activity at these sites. Using a bioenergetic model, we compared energy intake to energy expenditure and examined differences in behavior and foraging success of great egrets Ardea alba at three urban and three rural salt marshes in Narragansett Bay, Rhode Island USA. Mean per site available nekton energy averaged 4.44?±?0.97 GJ site^?1 and was significantly higher at urban than at rural sites. While energy expenditure by birds was similar across all sites, mean strike and prey capture rate were significantly greater at urban sites, and 70.1?±?12.2 % of strikes by egrets at urban sites were successful. Egrets foraging at urban sites consumed significantly more energy (23.2?±?6.62 W bird^?1) than those at rural sites. Model results indicated a net energy gain by egrets foraging at urban sites, versus a net energy loss at rural sites. Our results may help explain previously observed increases in the numbers of egrets foraging at urban marine habitats, and help provide input into decisions about the extent to which these areas should be considered for restoration or protection.     

Snake communities on the urban fringe in the Sonoran Desert: influences on species richness and abundance

Sonoran Desert habitat in southern Arizona is increasingly altered by urban development near metropolitan areas. Understanding how reptiles respond in these impacted habitats is critical to conservation efforts to retain intact biotic communities, especially those with a high diversity of reptile species. We surveyed snakes at one impacted site on the northern edge of the Phoenix metropolitan area in desert/urban interface, and at another site in a desert/rural interface near Florence, Arizona. The site near Phoenix was lower in species richness (15 spp.), and evenness: two snake species accounted for 75 % of all snakes encountered (total = 420). The site near Florence was higher in species richness (19 spp.), and a more even community: no species accounted for more than 20 % of snakes encountered (total = 594). Sampling methodology had a strong influence on species richness and abundance of snakes at the respective sites: road riding, coverboards, and traps each provided evidence of unique species missed by other methods. These results were compared with inventories at three other sites in the central Sonoran Desert of Arizona, and are consistent with the view that the impacted site near Phoenix is uneven, potentially as a result of a single species reacting to shifts in prey availability.     

Demography of a ground nesting bird in an urban system: are populations self-sustaining?

Urbanization poses threats to earth’s biota, and retention of remnant native habitat in protected areas within expanding urban boundaries may help alleviate threats to wildlife. However, it is unclear for nearly all nonsynanthropic (i.e., not benefiting from an association with humans) species whether vital rates in urban habitats can sustain populations or if populations persist only through immigration from outside the urban boundary. We conducted a three-year study of spotted towhees (Aves: Pipilo maculatus) breeding in four undeveloped parks in Portland, OR, USA, to measure park-specific seasonal reproductive output (F) and annual adult survival (S_A). We developed a stochastic model that combined F and S_A with an estimate of first-year survival to measure population growth rate (λ) in all parks assumed to be closed to immigration. F differed among parks but S_A did not. Relatively high F was possible because many pairs raised >1 brood/season. When combined with empirical estimates of survival through the 30-day period of post-fledging parental care (S_D = 0.645), only 2 of 4 parks were self-sustaining (i.e., λ > 1.0). However, S_D reflected substantial loss of fledglings to domestic cats (Felis catus). Assuming no loss to cats and either partial compensatory or additive mortality of fledglings substantially improved prospects of population persistence for declining (sink) populations. Moreover, allowing low levels of immigration to sinks reversed population declines in most parks even when vital rates were insufficient to maintain populations. Our results suggest that nonsynanthropic bird species can persist in urban landscapes, but also that offspring mortality in the post-fledging period may be a critical determinant of population viability.     

Richness, composition and trophic niche of stingless bee assemblages in urban forest remnants

Few studies directly address the consequences of habitat fragmentation for pollinating insect communities, particularly for the neotropical key pollinator group of stingless bees. Most studies on bees have defined habitat fragments as remnant patches of floral hosts or forests, overlooking the nesting needs of bees. Their conclusion is that habitat fragmentation is broadly deleterious; however, there are contrasting results in the literature. Insightful studies on habitat fragmentation and bees should consider fragmentation, alteration and loss of nesting habitats—not just patches of forage plants –, as well as the permeability of the surrounding matrix to interpatch movement. Here we investigated the effects of fragmentation caused by urbanization on stingless bee species’ composition and richness, as well as the permeability of the surrounding matrix. We collected bees from flowering plants and recorded phytosociological variables of five forest remnants (ranging from 64 ha to 900 ha) in southeastern Brazil. Large fragments did not contain more species per unit area than smaller ones; in fact, we found more species in small fragments, most of which were generalist bees. The presence of more habitat generalist stingless bee species was also correlated to the structure of vegetation in these fragments. In conclusion, the quality of the habitat within a fragment (structure of vegetation) as well as the quality of the matrix has a direct relation to the bee species composition. This can be seen in the direct relationship between structural diversity of the environment and age of the fragments. The matrix that holds the most recent fragments, probably due to the sprawl of the city, is more heterogeneous than the one with the oldest fragments. The most heterogeneous matrices have a certain balance between the trees, buildings and bare soil or herbaceous vegetation coverage, making the array less impermeable to bees.     

Variability of bumblebee communities (Apidae,Bombini) in urban green areas

Based on current research the agglomerations are potentially desirable habitats for bumblebees. However, the relationship between the biodiversity of these bees and the green areas where they live is poorly understood. The aim of the study was to estimate the influence of green areas (ranging from 8 to 102 ha) of big cities on bumblebee species richness, composition, and the relative number of these insects. The studies were conducted within the administrative borders of the city of Wroc?aw (Poland) in 2011–2012 in 12 green areas such as parks, cemeteries and other places with trees and shrubs. Species richness and abundance of bumblebees was determined by direct observation during 30 min. The gathered materials were used to calculate how areas of urban green space affected qualitative and quantitative bumblebee community structure. In total, 13 species of bumblebees (Bombus Latr.) were recorded, of which 3 belonged to cuckoo bumblebees (Psithyrus subgenus). The share of the most similar groups was congregated in green areas not smaller than 30 ha. This was proved by analysis of qualitative structure (Sørensen index), quantitative structure (Renkonen index), and qualitative-quantitative structure (Cody’s index). The number of bumblebee species in the surveyed green areas (r = 0.7497) was decisive for the arrangement of the mutual similarity of group structure. Green urban areas should be created in a size of at least 30 ha. Such sites provide conditions for the most diversified bumblebee species communities. Sites smaller than 30 ha can play an important role as refuges, and allow migration to all pollinators.     

How to improve urban greenspace for woodland birds: site and local-scale determinants of bird species richness

Wooded habitats represent hotspots of urban biodiversity, however, urban development imposes pressure on biota in these refuges. Identification of the most influential habitat attributes and the role of local urban characteristics is crucial for proper decisions on management practices supporting biodiversity. We aimed to identify well manageable fine-scale habitat attributes to suggest specific, feasible and affordable management recommendations for green space in cities. We analysed species richness of woodland-associated bird communities and incidence of individual species at 290 sites in a wide variety of green areas scattered across the city of Prague, Czech Republic. Generalized linear mixed models (GLMM) and regression tree analyses were used to identify site-scale (100 m radius sampling sites) and local-scale (200 m and 500 m radius plots) habitat attributes shaping the bird communities at individual sites. Logistic regression was used to assess the responses of individual species to habitat characteristics. Our results imply that at the site scale, management practices should focus on maintenance and promoting species-diverse and older tree stands, with a mixture of coniferous and deciduous trees. Water-bodies and accompanying riparian habitats should be maintained and carefully managed to preserve high-quality remnants of natural vegetation. Presence of a few old trees (about 12 % of tree cover with DBH?>?50 cm) or small urban standing water and watercourses enrich the bird community by at least two species. Species richness of woodland avifauna at particular sites is further supported by the total amount of tree cover in the surroundings, including scattered greenery of public spaces and private gardens. We conclude that proper management at site scale has the potential to increase biodiversity of the urban environment.     

Determining daytime resting site habitats of exurban feral cats

Predicting daytime resting sites (DRS) in feral cat (Felis catus) populations provides a means for further understanding what habitat characteristics are used by the species, which in turn may help in managing their populations. Between May – August 2013, we identified 319 summer DRSs used by 24 radiocollared feral cats in Russellville, Arkansas. Our goal was to characterize summer DRS use by feral cats via microhabitat and macrohabitat analysis in an exurban city. We identified DRSs by homing in on individuals between 1000 and 1600 h and sampled the habitat of one DRS for each cat weekly. We developed 13 a priori models focused on six micro- and macrohabitat variables that explained 97% of the data variability. Most cats used DRSs in thick vegetation or under anthropogenic structures, but we also observed cats inside anthropogenic structures, underground openings, and in open areas with no protective cover. Most DRSs were located within the open-low intensity developed land cover type. Two competing models that included 82% of the model weights indicated that DRS locations with relatively cooler temperatures, high overhead cover, and high ground-level visual obscurity were used frequently by cats. We also observed seven occasions of DRS sharing which were all within 165 m to known artificial food sources. Given the variety of habitats used by feral cats in this study, it would be difficult to predict specific daytime trapping locations with no established colony associated with a subsidized feeding area.

     

Predicting tree species richness in urban forests

There has been an increasing interest in urban forests and the levels of biodiversity they contain. Currently there are no spatially explicit maps of tree species richness in urban areas. This research tests and identifies GIS and remote sensing metrics (climate, area, productivity, three-dimensional structure) hypothesized to be associated with species richness in native forests and identifies methods that can be applied to predict and map tree species richness in cities. We quantified tree species richness, floristic composition, and structure in 28 1-ha plots in the city of Los Angeles. Climate and remote sensing metrics from high-resolution aerial imagery (10 cm), QuickBird (60 cm), Landsat (30 m), MODIS (250 m), and airborne lidar (2 m) were collected for each plot. There were 1208 individual stems and 108 trees identified to species. Species richness ranged from 2 to 31 species per ha and averaged 17 species per ha. Tree canopy cover from QuickBird explained the highest portion of variance (54%) in tree species richness followed by NDVI from Landsat (42%). Tree species richness can be higher in residential urban forests than native forests in the United States. Spatially explicit species richness maps at 1 ha can be created and tested for cities in order to identify both hotspots and coldspots of tree species richness and changes in species richness over time.     

Nest selection by red-headed woodpeckers across three spatial scales in an urban environment

Forest habitat is important for a variety of woodpecker species, and is under pressure from urbanization. Red-headed Woodpeckers (Melanerpes erythrocephalus; RHWO) were once abundant across Eastern North America, and their populations have been declining since the 1960s. Their distribution encompasses urban centers, and since urban habitats differ from natural forest areas, our goal was to understand RHWO nest-site selection in an urban context. We addressed two main questions 1) what are the characteristics of RHWO nest selection across multiple spatial scales and 2) how do RHWO nest tree characteristics in city parks compare to those in forest preserves? This work was done in Cook County, IL, which includes Chicago, the third-largest city in the USA by population. We examined 34 RHWO nest trees used between 2010 and 2013, their surrounding habitat, and the landscape within a 1 km radius. Used trees and habitats were compared to paired unused trees and habitats, and landscape-scale characteristics were compared to random locations. Advanced decay of the nest tree, low canopy cover and increased presence of fungus on trees in the surrounding habitat were the best predictors of RHWO nesting in the area. Nests were most commonly found in forested areas outside of dense urban areas. However, we did not detect significant differences in the characteristics of the nest trees located in forest preserves and city parks. Our findings are consistent with nest selection studies in rural and natural areas, suggesting that forest habitats in metropolitan landscapes can support RHWO nesting.     

Modeling above-ground carbon storage: a remote sensing approach to derive individual tree species information in urban settings

Vegetation has gained importance in respective debates about climate change mitigation and adaptation in cities. Although recently developed remote sensing techniques provide necessary city-wide information, a sufficient and consistent city-wide information of relevant urban ecosystem services, such as carbon emissions offset, does not exist. This study uses city-wide, high-resolution, and remotely sensed data to derive individual tree species information and to estimate the above-ground carbon storage of urban forests in Berlin, Germany. The variance of tree biomass was estimated using allometric equations that contained different levels of detail regarding the tree species found in this study of 700 km², which had a tree canopy of 213 km². The average tree density was 65 trees/ha per unit of tree cover and a range from 10 to 40 trees/ha for densely urban land cover. City-wide estimates of the above-ground carbon storage ranged between 6.34 and 7.69 tC/ha per unit of land cover, depending on the level of tree species information used. Equations that did not use individually localized tree species information undervalued the total amount of urban forest carbon storage by up to 15 %. Equations using a generalized estimate of dominant tree species information provided rather precise city-wide carbon estimates. Concerning differences within a densely built area per unit of land cover approaches using individually localized tree species information prevented underestimation of mid-range carbon density areas (10–20 tC/ha), which were actually up to 8.4 % higher, and prevented overestimation of very low carbon density areas (0–5 tC/ha), which were actually up to 11.4 % lower. Park-like areas showed 10 to 30 tC/ha, whereas land cover of very high carbon density (40–80 tC/ha) mostly consisted of mixed peri-urban forest stands. Thus, this approach, which uses widely accessible and remotely sensed data, can help to improve the consistency of forest carbon estimates in cities.     

Squirrels in suburbia: influence of urbanisation on the occurrence and distribution of a common exotic mammal

Urbanisation is widely considered to promote the establishment of non-native species, but there is limited empirical evidence of the ecological factors driving their responses. The grey squirrel Sciurus carolinensis (Gmelin 1788) is native to North America, but is widespread in the UK and is starting to spread across Europe. It is regarded as one of the world’s worst invasive animals due to its adverse impacts on native biodiversity. We use the non-native grey squirrel population in Sheffield (UK) as a case study to assess which factors limit its distribution and abundance in urban environments. In 2010 the city-wide population of adult squirrels peaked at an estimated 6539 in autumn (0.46 squirrels/ha), with maximum local densities of 8.29/ha. These densities appear to be slightly lower than those recorded in urban environments in the species’ native range. Grey squirrels occurred more frequently at urban sites with larger amounts of green-space in the surrounding region. Local habitat characteristics were, however, more powerful predictors of urban grey squirrel occurrence and abundance than regional availability of green space. Canopy cover, seed bearing trees and supplementary feeders, provided for garden birds, positively influenced grey squirrels. The potential for grey squirrels to connect city dwellers with nature thus appears to be highest in urban locations that have considerable capacity to support native biodiversity. The beneficial impacts of supplementary feeding on grey squirrel populations is notable given concerns that squirrels can adversely influence bird populations. These habitat associations also imply that grey squirrels typically respond negatively to urbanisation, which challenges arguments that urbanisation favours exotic species.     

Assessing the structural heterogeneity of urban areas: an example from the Black Country (UK)

The increasing acknowledgement of the importance of urban habitats in the maintenance of biodiversity has brought with it a need to quantify this importance at a scale appropriate to the characteristic patch sizes encountered in urban areas. Taking a study area in the Black Country (UK) we used a spatially complete, rapid assessment method to evaluate habitat patches in terms of their internal structural heterogeneity. This method recognises the importance of both natural and anthropogenic processes in providing a diverse range of habitats and niches for both flora and fauna. It also recognises the key role of context in determining the ecological significance of each patch within the urban landscape.All habitats studied had a complex mix of both natural and artificial structural elements, where an element is a within-patch contributor to structural diversity, with each habitat type having a large range of element totals. Characteristic totals, reflecting the level of habitat structural diversity, were observed in some habitat types with residential areas having high values and industrial and commercial areas having low values. Certain structural elements were also associated with each habitat type allowing characteristic element assemblages to be derived. If structural diversity is linked with biodiversity, as seems to be the case in many (though not all) habitat types, then this unique method of viewing the urban landscape becomes a powerful tool for informing wildlife ecologists, nature conservationists, urban planners, environmental managers and landscape architects.