Birds of a feather: Interpolating distribution patterns of urban birds

“…Additionally, birds are monitored seasonally at 40 sites (5 agriculture, 14 desert, and 31 urban) with the CAP LTER study area ( Fig. 1) (Walker et al 2008).This design maximizes the density of points within the urban landscape while spatially balancing sampling at the regional scale. Beginning fall 2002, seasonal bird counts have been conducted at these sites by three observers per site, including winter (January), spring migration (April), summer breeding (July), and fall migration (October).…”

Section: Study Area and Sampling Designmentioning

confidence: 99%

“…A strong peak is expected for species directly dependent on vegetation for food (herbivores), a weaker peak for omnivores, and the weakest relationship for those species indirectly dependent on vegetation (insectivores). The regional distributional patterns of the varying bird functional groups was also estimated by utilizing interpolation techniques designed for avian censuses in urban systems (Walker et al 2008). Exotic species were expected to be spatially aligned to the urban ecosystem, and native species tied to the desert ecosystem.…”

mentioning

confidence: 99%

Scalar effects of vegetation on bird communities in an urbanizing desert ecosystem

Walker

Shochat

2009

Urban Ecosyst

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We analyzed how urbanization in a desert ecosystem affects avian distribution at two distinct scales. At the regional level, we compared how urban land use configuration, relative to its surrounding agricultural fields and desert, affected the distribution of native and exotic species. While exotic species are isolated to the city; native species actively utilize the entire region, even occurring at higher densities in the city than in some areas of the desert. We also used this approach to compare four foraging guilds of birds: granivores, nectivores, omnivores, and insectivores. Granivores occurred mostly in agricultural fields and in the surrounding urban areas. Nectivores and omnivores occurred throughout the region, but mostly within the city. In contrast, insectivores occurred mostly in the desert. At a more local scale, we tested how the abundance of native species, exotics species and the foraging guilds of birds responded to vegetation cover measured at varying spatial scales (0.1 km-10 km). Bird guilds responded to vegetation at different scales, depending on the association between their life history and vegetation. Granivore abundance was most strongly correlated with vegetation at relatively fine spatial scales, followed by nectivores and omnivores at larger scales; whereas insectivores did not correlate with vegetation at any scale. Exotic and native species showed strikingly opposite trends in their association with vegetation. Native species showed the best fit at the smallest spatial scale and became insignificant at larger scales, whereas the highest correlation of exotic species with vegetation was at moderate to larger scales. While guild relationship with vegetation appears straightforward, the differences between exotic and native birds may indicate a complex response to environmental factors. Possibly, native species are more sensitive than exotics on vegetation abundance for food and shelter, which in the desert is highly variable Urban Ecosyst (2010) 13:155-167 depending on water availability. In contrast, exotic species, tightly connected to the urban infrastructure, likely respond to the enhanced and homogenized resource abundance characteristic of desert cities. Our results suggest that relationships between birds and vegetation may bear important information that can be revealed when considering smaller class levels than total species diversity.

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“…This method results in a continuum of interpolated information conformed by predicted pixels. Due to its robustness, this method is widely used in several disciplines and is starting to become common in ecological studies [33,[52][53][54]. To generate interpolated information based on our butterfly surveys, we square root transformed the observed abundances per sampling site in order to comply with normality and skewness [55].…”

Section: Discussionmentioning

confidence: 99%

“…Based on the urgent need to generate data that can provide ecological bases for urban managers and planners, as well as environmental educators [32,33], we used a citywide approach to estimate the total number of butterfly individuals (Insecta: Lepidoptera; only considering Papilionoidea; referred to as butterflies hereafter) that dwelt in a medium sized neotropical city (Xalapa-Enriquez, referred to as Xalapa hereafter). For this, we used ordinary kriging, a geostatistical interpolation procedure that allowed us to generate a citywide estimate (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

How Many Butterflies Are There in a City of Circa Half a Million People?

2015

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Urbanization poses severe threats to biodiversity; thus, there is an urge to understand urban areas and their biological, physical, and social components if we aim to integrate sustainable practices as part of their processes. Among urban wildlife groups, butterflies have been used as biological indicators due to their high sensitivity to environmental changes. In this study, we estimated the number of butterflies that live within a neotropical medium-sized city (Xalapa, Veracruz, Mexico) using a robust interpolation procedure (ordinary kriging). Our calculations added an average of 1,077,537 (± SE 172) butterfly individuals that dwelt in Xalapa in the surveyed space and time. The interpolation procedures showed to be robust and reliable, and up to some extent conservative. Thus, our results suggest that there are at least 1.8 butterfly individuals per capita in Xalapa. Notably, higher butterfly abundances tended to be recorded near highly vegetated areas and along city borders. Besides providing the basis for further ecological studies, our results will contribute to the crucial need of scientific data that is lacking, but critically important, for adequate urban management and planning, as well as environmental education.

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Birds of a feather: Interpolating distribution patterns of urban birds

Cited by 23 publications

References 19 publications

Biodiversity on the Urban Landscape

Biodiversity on the Urban Landscape

Scalar effects of vegetation on bird communities in an urbanizing desert ecosystem

How Many Butterflies Are There in a City of Circa Half a Million People?

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