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Article

Contribution of Seasonal Streams to the Conservation of Native and Migratory Birds in a Coastal Region Undergoing Urbanization

by
Catalina B. Muñoz-Pacheco
,
Javiera C. Gutiérrez
and
Nélida R. Villaseñor
*
Ecology, Nature and Society Group (ECONAS, Grupo de Ecología, Naturaleza y Sociedad), Department of Forest Management and Environment, Faculty of Forestry and Nature Conservation, University of Chile, Santiago 8820808, Chile
*
Author to whom correspondence should be addressed.
Birds 2025, 6(1), 8; https://doi.org/10.3390/birds6010008
Submission received: 22 November 2024 / Revised: 10 January 2025 / Accepted: 26 January 2025 / Published: 6 February 2025
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Simple Summary

Urbanization significantly alters natural landscapes, threatening biodiversity by decreasing native species’ richness and abundance. In coastal regions undergoing urban development, seasonal streams commonly retain remnant vegetation and may serve as refuge areas for native birds. Despite their potential contribution to bird conservation, few studies have examined these areas. To investigate the role of seasonal streams in conserving native terrestrial avifauna in Algarrobo, an expanding urban area on the coast of central Chile, we compared bird diversity in seasonal streams (n = 18) and residential zones (n = 18). Bird counts were conducted during summer and winter. We employed Generalized Linear Mixed Models (GLMMs) to analyze the richness, abundance, and diversity of native terrestrial birds and the abundance of six migratory species. Species accumulation curves ensured adequate sampling of species present. Our findings indicated that seasonal streams supported more native and endemic bird species than residential areas. A notable increase in the abundance of two migratory bird species (Green-backed Firecrown and Gray-hooded Sierra Finch) was recorded during winter in seasonal streams. These results emphasize seasonal streams’ critical role in conserving native and migratory birds, highlighting the need for their protection and effective management to maintain avian biodiversity in urbanized landscapes.

Abstract

Urbanization has drastically transformed natural landscapes, threatening biodiversity by reducing species richness and abundance in cities. In this context, seasonal streams serve as refuge areas for various bird species. To determine the role of seasonal streams in conserving native terrestrial avifauna in Algarrobo, an expanding urban environment, we compared bird diversity in ephemeral streams (n = 18) and residential areas (n = 18). Bird counts were conducted during summer and winter. We utilized a diversity index and Generalized Linear Mixed Models (GLMMs) to assess the richness and abundance of native terrestrial birds, as well as the abundance of six migratory birds. Additionally, species accumulation curves verified whether most present species had been adequately sampled. Our results revealed that seasonal streams harbored a greater richness of native bird species than residential areas. Endemic species were also recorded in these streams. The cumulative number of bird species was higher in the seasonal stream environment compared to residential areas. During winter, a higher abundance of migratory birds (Green-backed Firecrown and Gray-hooded Sierra Finch) was observed in seasonal streams. These findings suggest that seasonal streams play a crucial role in conserving native and migratory birds. Thus, protecting and managing these habitats is essential for maintaining avian biodiversity in urbanized areas.

1. Introduction

Urbanization, a constantly expanding global phenomenon, affects fragile natural habitats and threatens species’ survival [1]. In 1900, only 10% of the world’s population lived in urban areas [2]; however, the current urban population has reached 57% [3]. This urban expansion leads to habitat loss and fragmentation, putting the survival of multiple species at risk [4]. Many species are displaced or excluded from urban ecosystems due to the lack of important habitat structures (e.g., trees) [5]. Global assessments show that urban expansion has caused a loss of 50% of local species’ numbers and 38% of total species’ abundance compared to natural areas [6]. By 2100, urban land conversion is projected to reduce local species richness by 34% and species abundance by 52% [4].
Urban landscapes encompass a wide variety of environments, ranging from fragments of remnant habitat to highly modified areas, which impact species in different ways [7]. In this context, urban streams and riparian zones can provide important services to cities and sustain notable biodiversity [8,9]. In fact, riparian habitats contribute to a global increase in regional species richness by over 50% on average [10]. These environments provide water availability for plants and vertebrates throughout the year, serving as refugia for many species, such as birds [10,11]. However, riparian ecosystems in urbanized areas have been neglected for centuries and are often in an advanced state of degradation [9].
Riparian zones and seasonal streams are essential elements of the urban habitat mosaic, serving as important refuges for various species, including birds, butterflies, and plants [8]. For native birds, stream ecosystems provide vital habitats that offer both nesting areas and shelter within the riparian vegetation [9]. Natural streams have also been identified as key supports for the presence of numerous migratory passerine bird species [12]. Consequently, these spaces acquire special significance as strategic refuges for migratory birds facing the challenges of urban environments for their survival [13]. However, studies on avifauna in riparian areas associated with ephemeral streams in urban settings are scarce [8,9]. Previous studies on riparian ecosystems in urban areas have not specifically assessed endemic bird species (e.g., [8,9,10,11,12]), despite their crucial role in maintaining local biodiversity. Endemic species are particularly relevant in the context of urban streams as they are often adapted to specific environmental conditions and may serve as important indicators of habitat quality and ecological integrity [14].
In particular, the remaining natural vegetation preserved in and around urban areas can play a crucial role in biodiversity conservation [14,15]. To better understand the role that seasonal streams play in preserving native terrestrial birdlife in coastal areas undergoing urban development, we assessed birds’ richness, abundance, and diversity in seasonal stream zones and residential areas in the coastal town of Algarrobo, Chile. We analyzed the average abundances by species, including endemic and exotic species. Additionally, we specifically analyzed the abundance of migratory birds in these two habitat types. This approach allowed us to determine how seasonal streams and residential areas contribute to bird conservation, providing valuable insights into the importance of riparian ecosystems in urban contexts.

2. Materials and Methods

2.1. Study Area

The study was conducted in the municipality of Algarrobo (latitude 33°21′, longitude 71°40′), Valparaíso Region, Chile. The municipality has a population of approximately 14,000 inhabitants, with 11,060 inhabitants (79% of the total) living in the urban area [16]. It is characterized by a coastal bioclimate with moderate temperatures (14.5 °C annual average) and higher-than-average precipitation for the region (458 mm annual average). The original vegetation consists of sclerophyllous forest and arborescent sclerophyllous shrubs [17]. Native vegetation is primarily restricted to areas around permanent or seasonal streams, which constitute the only green spaces within the municipality, with 15 streams running east to west across the municipality [16].

2.2. Sampling Sites

Sampling sites were selected in two adjacent habitat types: seasonal streams (n = 18) and residential areas (n = 18) within the urban area of Algarrobo (Figure 1). Three sampling sites were randomly placed at each of the six seasonal streams located in the study area, and at each of the six residential areas located next to the seasonal streams. All sites were separated by a minimum distance of 300 m from each other.

2.3. Bird Assessment

Birds were surveyed during the austral summer (February 2023) and austral winter (August 2023). All bird counts were conducted in the morning (7:00–11:00 a.m.) to coincide with the peak bird activity and on days with favorable weather conditions (i.e., no rain, fog, or wind [18,19]). At each site, the point count method was used, recording all birds seen or heard within a 50 m radius for 5 min [20]. Observations were conducted at 10 m intervals up to the 50 m limit, excluding birds flying over the area unless they were observed using the site (e.g., swallows hunting insects) [21]. Bird counts were conducted twice per season at the 36 sites to minimize bias associated with specific weather conditions on a given day [19].

2.4. Statistical Analyses

To compare environments, we focused on terrestrial birds by excluding species associated exclusively with water bodies, such as ducks, grebes, and herons. This allowed us to focus on species common to both habitat types studied, facilitating a more balanced comparison.
We calculated the average abundance of birds per species (native and exotic) based on observations made at 30 m from each sampling point. Observations of individuals within each habitat and season were averaged for each species. The standard error (SE) of abundance was estimated from the standard deviation of the abundances observed at each sampling point, divided by the square root of the number of sampling points in each habitat and season.
We used species accumulation curves to assess sampling completeness in each environment with the vegan package in R version 3.4.4 [22]. These curves helped determine whether the number of samples collected was sufficient to capture most species present.
To assess differences in the species richness and abundance of native birds as well as the abundance of migratory bird species among residential areas and seasonal streams, we employed Generalized Linear Mixed Models (GLMMs) with a Poisson distribution. To fit the models, we used the species richness of native birds recorded at a 50 m radius plot and the abundance of both native and migratory birds recorded at a 30 m radius plot, as detecting birds at larger distances is more challenging in seasonal stream environments [23] (Figure A1). Migratory species were identified following Martínez and González (2017) [24] (Table A1). We built one model for each migratory bird species that was observed in at least 10% of the counting points [23]. In these models, the type of environment (two levels: urban and stream) and season (summer and winter) were included as fixed factors to estimate their effects on bird richness and abundance. At the same time, the sampling site was included as a random factor to account for spatial dependence in data [25]. All models were evaluated for overdispersion with overdisp_fun [26]. The analyses were performed using R version 3.4.4. The following packages were used: lme4 for GLMMs [27] and lmerTest to perform statistical significance tests on the models [28].
Additionally, we calculated diversity indices for native birds (within a 30 m radius) across different environments and seasons, including the Shannon–Wiener Diversity Index (H′) and Simpson’s Diversity Index (D) using the software PAST. We analyzed the Jaccard Similarity Index for each sampling site, including six seasonal streams and six residential areas adjacent to the streams, during summer and winter. The analysis focused exclusively on native terrestrial bird communities and was conducted using the software PAST. Hierarchical clustering was then performed to evaluate the degree of similarity between sites in terms of bird community composition across seasons.

3. Results

A total of 49 native bird species (31 native terrestrial birds) and three exotic bird species were recorded in Algarrobo. In seasonal stream environments, 34 native species (30 native terrestrial birds) and two exotic species were documented, while in residential areas, 22 native species (21 native terrestrial birds) and two exotic species were recorded (Figure 2). The exotic species present in urban environments, the House Sparrow (Passer domesticus) and the Rock Dove (Columba livia), showed high abundance (Figure 2).
The species accumulation curves revealed a higher cumulative number of bird species in the seasonal stream environment (32 species) compared to the residential area (21 species) across 30 sampling points (Figure 3).
The richness of native bird species recorded in the seasonal stream environment was significantly higher than that recorded in residential areas (p < 0.001). We found no significant differences in the richness of native bird species between seasons (p = 0.904) (Figure 4A). In terms of the abundance of native bird species, the seasonal stream environment showed significantly higher abundance compared to residential areas (p < 0.001). No significant differences were found in the abundance of native bird species between seasons (p = 0.107) (Figure 4B). The Shannon Diversity Index (H′) indicates a greater diversity of native birds in seasonal streams during summer and winter (Figure 4C). Simpson’s Diversity Index (D) indicates that seasonal streams host a more diverse and balanced bird community in both summer and winter (Figure 4D).
From the Jaccard Similarity Index dendrogram for native terrestrial birds, it can be observed that during summer, the arrangement of sites indicates a distinct grouping, with some residential areas (e.g., R-4 and R-2; Figure 5) clustering closely with seasonal streams (e.g., SS-4 and SS-5). In contrast, during winter, the seasonal stream sites are more tightly clustered (e.g., SS-4, SS-5, and SS-6), as are the residential sites (e.g., R-4, R-3, and R-6).
Only migratory passerine birds were recorded in the study area (Table A1). The migratory species included in the statistical analyses were the Green-backed Firecrown (Sephanoides sephaniodes), Gray-hooded Sierra Finch (Phrygilus gayi), Chilean Swallow (Tachycineta leucopyga), and White-crested Elaenia (Elaenia albiceps). Additionally, Giant Hummingbird (Patagona gigas) and Patagonian Tyrant (Colorhamphus parvirostris) were recorded but excluded because they were not observed in at least 10% of the counting points. For the Green-backed Firecrown (S. sephaniodes), the abundance in the seasonal stream environment was significantly higher than in residential areas (p < 0.001), and a higher abundance was also observed in winter compared to summer (p = 0.017) (Figure 6A). Similarly, the Gray-hooded Sierra Finch (P. gayi) showed significantly greater abundance in the seasonal streams compared to residential areas (p = 0.009), and its abundance was also significantly higher in winter than in summer (p = 0.027) (Figure 6B). In contrast, the Chilean Swallow (T. leucopyga) did not show a significantly higher abundance in the seasonal stream environment compared to residential areas (p = 0.06), though its winter abundance was markedly higher than in summer (p < 0.001) (Figure 6C). The White-crested Elaenia (E. albiceps), on the other hand, showed no significant differences in abundance between environments (p = 0.53) and was recorded exclusively during the summer (Figure 6D).

4. Discussion

Urbanization and land-use change in central Chile have accelerated over recent decades, exerting significant pressure on natural ecosystems [29]. This process has transformed areas once covered by native vegetation into land used for anthropogenic activities, such as residential, commercial, and tourism purposes [17,29]. Consequently, natural vegetation has become fragmented and is now restricted to isolated patches in less accessible areas or locations of lower interest for urban development, such as seasonal stream zones [16]. The loss of vegetation cover associated with stream environments not only reduces biodiversity but may also diminish habitat connectivity, affecting the dispersal and survival of native species [30]. In this context, preserving the remaining natural vegetation is of critical importance, as these patches can support endemic or threatened native fauna species within urbanized landscapes [14].
Our study highlights that seasonal stream environments are important for bird conservation in Algarrobo, a coastal area facing the pressures of urban development that threaten its natural heritage. Seasonal streams supported greater richness, abundance, and diversity of native bird species compared to residential areas, with consistent patterns observed across seasons. Furthermore, seasonal streams had a higher abundance of two migratory passerine species (Green-backed Firecrown and Gray-hooded Sierra Finch), particularly during the winter months. Therefore, safeguarding these vital habitats is essential not only for preserving diverse avian populations but also for maintaining the ecological health and resilience of the region in the face of ongoing urbanization.

4.1. Diversity of Native Birds

Species accumulation curves and average point richness analyses indicate that seasonal streams host a higher richness of native birds compared to residential areas. This pattern suggests that seasonal streams provide more favorable conditions for avian biodiversity, likely due to their greater structural diversity and the presence of native vegetation [31], which offers refuge, nesting sites, and food resources. In contrast, residential areas, with less vegetation cover and greater habitat fragmentation, are less suitable for many species, as reflected in lower bird richness [32]. This finding emphasizes the importance of preserving seasonal streams as key spaces for native birds, as their conservation would contribute to maintaining biodiversity in urban environments. It highlights the need for urban conservation policies that promote the protection of these habitats, supporting ecological connectivity and the conservation of vegetation in urban settings (e.g., [33,34,35]).
The seasonal stream environment exhibited greater richness, abundance, and diversity of native bird species compared to residential areas. Intercontinental comparisons further reinforce these findings. Studies in tropical riparian forests have demonstrated that natural areas support higher bird densities than transformed riparian habitats [36]. Additionally, greater bird diversity, particularly among granivorous species, has been documented near water bodies [37]. These results align with previous research that highlights the importance of riparian zones, primarily due to the presence of greater vegetation, for biodiversity conservation in urban settings (e.g., [8,10,38]). It is suggested that habitat diversity in streams or rivers, along with greater vegetative cover, plays a crucial role in bird conservation [8,38,39]. The presence of vegetation, especially woody plants, is a key determinant in fostering higher bird richness and abundance in urban environments [21,23,40,41,42]. In this regard, trees and shrubs in riparian zones can provide food resources and nesting opportunities [39]. Therefore, the absence of these structural habitat components could compromise the persistence of biodiversity in urban riparian corridors [8]. Therefore, the integrated preservation and careful management of water bodies and their surrounding riparian habitats are crucial for maintaining high-quality remnants of natural vegetation [41].
The differences in species presence between seasonal streams and residential areas are marked, reflecting the specialization of avian communities in each habitat. Seasonal streams hosted endemic species such as Dusky-tailed Canastero (Pseudasthenes humicola), White-throated Tapaculo (Scelorchilus albicollis), and Moustached Turca (Pteroptochos megapodius), as well as forest specialists like Chilean Pigeon (Patagioenas araucana) and Striped Woodpecker (Veniliornis lignarius). These findings suggest that seasonal streams offer more favorable conditions for native species that depend on less disturbed, natural habitats [43]. In contrast, residential areas exhibit a high average abundance of exotic species, such as House Sparrow (P. domesticus) and Rock Dove (C. livia), which thrive in highly modified urban environments (e.g., [44,45]). This pattern aligns with previous research, which has shown that greater impervious surface cover is often linked to a higher abundance of exotic species [23]. Specifically, bird communities in urbanized environments, like residential areas, tend to be dominated by House Sparrow (P. domesticus) and Rock Dove (C. livia), in contrast to areas with more vegetation cover, such as parks and vacant lots [46]. However, in our study area, there is a notable lack of green spaces [16], making seasonal streams even more critical as refuges for native biodiversity. This pattern highlights the importance of conserving seasonal streams as key refuges for native biodiversity, while residential areas, dominated by invasive species, require distinct management approaches to mitigate the negative impacts of exotic species [47].
The lower richness and abundance of native birds in residential areas, compared to environments with greater vegetation cover, has been documented. Several studies have shown that urban areas tend to support less bird richness and abundance compared to environments with greater vegetation cover, such as natural, rural, peri-urban areas, and vacant lots [15,46,48,49]. Additionally, it has been shown that in riparian zones, bird diversity is negatively correlated with impervious surface area and building density [38,50]. In comparison with the study conducted by Graells et al. (2022) [44] in Valparaíso, a coastal city near Algarrobo (36 km away) but with greater urban development, we recorded forest specialists such as Chilean Pigeon (P. araucana) and Striped Woodpecker (V. lignarius), and endemic species such as Dusky-tailed Canastero (P. humicola), White-throated Tapaculo (S. albicollis), and Moustached Turca (P. megapodius). These species were not detected in the Valparaíso study, highlighting the importance of habitats with greater vegetation cover and lower urbanization levels for the conservation of these birds. The importance of remnants of natural vegetation for endemic fauna was also described in central Chile by Muñoz-Pacheco et al. (2023) [14] in a peri-urban area (20 km from Algarrobo), where shrubland and hydrophilic forest sustain endemic and threatened species in a landscape dominated by urban and exotic tree plantations. Therefore, preserving native vegetation plays a crucial role in supporting native bird diversity in urbanized regions.
The limited seasonality in bird richness, abundance, and diversity observed across the study area suggests that seasonal streams and adjacent urban areas provide relatively stable resources and habitat conditions throughout the year. This stability may result from the continuous availability of anthropogenic food sources [50] and the buffering effects of urban vegetation, which mitigate seasonal fluctuations commonly seen in natural ecosystems [51]. These findings highlight the potential of urban riparian habitats to consistently support bird populations, emphasizing their importance as conservation priorities in urban planning and management. Despite the constancy in diversity, the community assembly of native terrestrial birds varied seasonally. Changes in species composition may contribute to the stability of bird abundance across seasons, possibly due to reduced competition for resources [52]. It is necessary to conduct further studies to understand how factors like seasonal food availability, habitat preferences, and migration [52] may drive changes in species composition and contribute to the stability of bird richness, abundance, and diversity.
Although the results show significant bird richness and abundance differences between seasonal streams and residential areas, limitations should be considered. The point count method, while widely used, may be subject to biases such as the detection of nocturnal species (e.g., Tyto furcata, Glaucidium nana, Strix rufipes, Systellura longirostris [14]) or elusive species (e.g., Nothoprocta perdicaria [14]), and variations in vocal activity or daily behaviors of species [53,54]. These limitations should be considered when interpreting the findings.

4.2. Abundance of Migratory Bird Species

A greater abundance of two migratory passerine species (Green-backed Firecrown and Gray-hooded Sierra Finch), was recorded in the seasonal stream environment, especially during the winter. This highlights the significance of Algarrobo as a habitat that supports populations of migratory species year-round, primarily in these seasonal stream environments. Previous studies have shown that Neotropical migratory birds tend to use areas with extensive riparian forests and less urban development [55]. Moreover, it has been documented that the richness and density of migratory birds decrease in urbanized environments, primarily due to the reduction in vegetation cover [40,56,57,58]. Thus, vegetation, especially woody vegetation, can enhance winter habitat conditions in urban ecosystems by providing food resources, shelter for resting, and protection against predators and adverse weather conditions, such as rain and low temperatures [58]. Furthermore, urbanization has been observed to have a more significant negative effect on Neotropical migratory bird communities than on resident bird communities [40].
For Green-backed Firecrown, we observed higher abundance in seasonal stream environments and during winter. This pollinator species mainly reproduces in austral regions and migrates to northern wintering sites in the autumn [24]. During autumn and winter, Green-backed Firecrown is a common visitor to urban gardens with flowering shrubs and trees in central Chile [59]. Other studies have also identified a greater abundance of individuals in urban green spaces compared to residential areas, specifically urban parks [32,44]. This suggests a positive effect of woody vegetation cover (trees and shrubs) in urban settings, as these habitats can provide food and shelter for this hummingbird [58,60].
For Gray-hooded Sierra Finch, a higher abundance was recorded in seasonal stream environments and during winter. This species, a granivorous and altitudinal migrant, descends from the mountain range to the valleys and the coast in the winter season [24]. Gray-hooded Sierra Finch has been rarely observed in urban environments (e.g., [61,62]) and shows a greater abundance in rural areas [62]. The low frequency of observations in urban settings may suggest that Gray-hooded Sierra Finch is sensitive to the effects of urbanization [63], highlighting the need to investigate how the loss of rural or natural habitats due to urban expansion affects its distribution patterns. Additionally, bird species with specialized diets, such as granivores, tend to be less tolerant of urbanization processes [64]. Therefore, conserving less urbanized habitats, like seasonal streams, could support their seasonal movements by providing essential food sources, resting areas, and shelter along migratory routes.
In contrast, the Chilean Swallow did not show a significantly higher abundance in seasonal stream environments compared to residential areas; however, its abundance was markedly higher in winter than in summer. This species has been recorded as abundant in small cities (under 10 km2, [62]) and informal green spaces with spontaneous vegetation [32]. Similar to these settings, Algarrobo is a small town with substantial vegetation; however, urban expansion could pose a risk if not carefully managed. Reductions in vegetation within urban areas decrease insect availability, resulting in suboptimal feeding conditions for insectivorous species like the Chilean Swallow [40,65]. Currently, residential zones in Algarrobo are interspersed with seasonal streams bordered by semi-natural vegetation, which likely supports Chilean Swallow by providing food resources and shelter. Preserving these vegetated spaces could be essential for protecting this species as urban development continues to grow.
The abundance of White-crested Elaenia did not differ significantly between residential areas and seasonal stream environments, indicating that both habitat types may offer comparable conditions for this species. This bird arrives in central Chile during the breeding season, where it ranks among the ten most abundant native species in urban settings [19,23]. It is commonly found in high abundance in green areas and at lower densities in residential zones in Santiago, the capital of Chile [32]. Further studies in this large city have shown that White-crested Elaenia abundance peaks when woody vegetation covers 20–30% of the area within a 50 m radius, after which it declines [23]. In Algarrobo, residential properties and public spaces often contain woody vegetation, such as shrubs and small trees, in front and back gardens or along streets, which may support the presence of White-crested Elaenia. Additionally, these residential areas are limited by nearby seasonal streams, bordered by semi-natural vegetation. These findings suggest that urban areas with sufficient, accessible vegetation, including semi-natural spaces, may continue to support White-crested Elaenia populations.

4.3. Conservation Implications

Given the crucial role that seasonal stream environments play in conserving native and migratory birds in urban settings, it is essential to preserve these ecosystems. These streams provide habitat for various species, including aquatic birds and migratory songbirds, and promote habitat connectivity, contributing to biodiversity maintenance and facilitating movements between otherwise isolated populations [8,12]. However, the increase in impermeable surfaces and the growing human presence in these areas can significantly alter vegetation composition and structure, reducing trees and shrubs [55,66]. This reduction can have a negative impact on bird communities, as woody vegetation is crucial for the richness and abundance of native birds in urban environments [18,23,41]. Therefore, maintaining healthy riparian vegetation in urban areas is vital for sustaining diverse and robust bird populations.
Even though riparian zones and ephemeral streams constitute an important part of the urban habitat mosaic, they face significant threats to their preservation. Increased urbanization has been observed to bring about significant changes in the vegetation structure of riparian areas [8]. Anthropogenic threats can alter not only the vegetation but also water regimes and quality, as well as geomorphological characteristics, affecting various species and the ecological interactions that depend on these habitats [67]. The main causes of this degradation include the absence of vegetation, structured channelization, high density of human settlements, waste dumping, sediment dredging, and the use of these streams as conduits for wastewater disposal and vehicular traffic [38,67]. These alterations in stream environments contribute to a decline in bird diversity over time [12]. Consequently, future research should include long-term monitoring and threats to the conservation of avifauna, such as pollution or loss of vegetation.
A concerning aspect is the lack of adequate protection for these environments. Ephemeral streams have less legal protection worldwide compared to permanent streams, reflecting the limited social recognition of their ecological attributes and ecosystem services [67]. This situation is particularly alarming because ephemeral streams, despite their temporary nature, play a crucial role in supporting native and migratory birds. Therefore, it is essential to implement conservation actions that ensure the preservation of these ecosystems, minimizing their degradation and the loss of biodiversity [38]. Additionally, policies are needed to integrate the ecological value of these habitats into urban management plans to mitigate the impact of human activities on them.
In the context of Algarrobo, the lack of legal protection for stream ecosystems is a significant concern. Currently, the Communal Regulatory Plan of Algarrobo [68] does not include specific measures for protecting these habitats, nor are they considered for conservation in the Intercommunal Regulatory Plan of Valparaíso [69]. This situation reflects a regulatory gap that exposes the streams to risks from increasing urbanization and ecosystem alterations. Furthermore, according to the Ministry of the Environment of Chile, the endemic species recorded in this study do not have legal protection [70], further exacerbating the vulnerability of these species to urban and environmental pressures. This lack of protection highlights the urgent need for public policies and management plans that properly recognize and safeguard these valuable urban ecosystems.

5. Conclusions

Our study highlights the importance of seasonal streams as critical habitats for conserving native and migratory birds in a coastal urban landscape in Algarrobo, Chile. These environments support greater richness, abundance, and diversity of native birds, forest specialists, and endemic species compared to residential areas, underscoring their relevance for biodiversity with increasing urbanization. Furthermore, seasonal streams provide critical habitat resources for migratory birds, particularly during winter. The conservation of these habitats and the protection of their riparian vegetation are essential to mitigate the negative impacts of urban development on bird communities, especially in areas where formal green spaces are limited. This requires management strategies that prioritize the preservation of native vegetation fragments and promote their connectivity with other urban green spaces.

Author Contributions

Conceptualization, N.R.V.; methodology, C.B.M.-P. and J.C.G.; data collection, C.B.M.-P. and J.C.G.; formal analysis, C.B.M.-P.; investigation, C.B.M.-P.; resources, N.R.V.; writing—original draft preparation, C.B.M.-P.; writing—review and editing, N.R.V.; visualization, C.B.M.-P. and J.C.G.; supervision, N.R.V.; project administration, N.R.V.; funding acquisition, N.R.V. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by ANID-Fondecyt, grant number 11201045 (Government of Chile).

Institutional Review Board Statement

Not applicable.

Data Availability Statement

Data will be made available on request.

Acknowledgments

We thank Carolina Mujica, who contributed to the data collection and Isaac Peña-Villalobos for hosting us at his house.

Conflicts of Interest

The authors declare no conflicts of interest.

Appendix A

Birds 06 00008 g0a1
Figure A1. Frequency of bird detections by distance range during point counts.
Figure A1. Frequency of bird detections by distance range during point counts.
Birds 06 00008 g0a1
Table A1. Average abundance of recorded terrestrial species, their geographic origin (Nat: native; End: endemic; Exo: exotic), and migratory status (* migrants).
Table A1. Average abundance of recorded terrestrial species, their geographic origin (Nat: native; End: endemic; Exo: exotic), and migratory status (* migrants).
Seasonal StreamsResidential
SpeciesOriginMigrantSummerWinterSummerWinter
Geranoaetus polyosomaNat 0.10.00.00.0
Parabuteo unicinctusNat 0.10.00.00.0
Daptrius chimangoNat 0.10.00.10.0
Callipepla californicaExo 0.00.40.00.0
Larus dominicanusNat 0.00.00.10.1
Columba liviaExo 0.00.00.20.8
Patagioenas araucanaNat 0.00.10.00.0
Zenaida auriculataNat 0.20.30.30.4
Patagona gigasNat*0.40.00.10.0
Sephanoides sephaniodesNat*0.71.40.10.2
Veniliornis lignariusNat 0.10.20.00.0
Aphrastura spinicaudaNat 0.70.80.00.1
Leptasthenura aegithaloidesNat 0.20.40.40.3
Pseudasthenes humicolaNat/End 0.20.00.00.0
Pteroptochos megapodiusNat/End 0.00.10.00.0
Scelorchilus albicollisNat/End 0.20.00.00.0
Scytalopus fuscusNat 0.20.40.00.0
Anairetes parulusNat 0.90.40.30.1
Colorhamphus parvirostrisNat*0.00.30.00.1
Elaenia albicepsNat*0.60.00.50.0
Pyrope pyropeNat 0.50.60.00.2
Phytotoma raraNat 0.20.40.40.5
Tachycineta leucopygaNat*0.20.30.10.3
Troglodytes aedonNat 1.41.00.50.9
Turdus falcklandiiNat 0.90.81.00.8
Mimus thencaNat/End 0.30.30.40.4
Diuca diucaNat 0.90.80.50.7
Phrygilus gayiNat*0.20.60.10.1
Zonotrichia capensisNat 0.81.20.81.7
Agelaius thiliusNat 0.10.30.00.0
Curaeus curaeusNat 0.30.10.10.1
Leistes loycaNat 0.10.20.00.1
Spinus barbatusNat 0.10.90.00.4
Passer domesticusExo 0.40.02.12.1

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Figure 1. Sample sites and location of seasonal streams inside the urban boundaries of Algarrobo, Chile. For both types of sample sites, an example photograph is provided.
Figure 1. Sample sites and location of seasonal streams inside the urban boundaries of Algarrobo, Chile. For both types of sample sites, an example photograph is provided.
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Figure 2. Average abundance and standard error of bird species per point count (30 m radius) in (A) seasonal streams and (B) residential areas, during winter and summer seasons. * Represents exotic species.
Figure 2. Average abundance and standard error of bird species per point count (30 m radius) in (A) seasonal streams and (B) residential areas, during winter and summer seasons. * Represents exotic species.
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Figure 3. Estimated cumulative species richness across sampling points in seasonal streams (green) and residential environments (grey).
Figure 3. Estimated cumulative species richness across sampling points in seasonal streams (green) and residential environments (grey).
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Figure 4. Values estimated by GLMMs for each environment and season of (A) average richness of native bird species per point count (50 m radius) and (B) average abundance of native bird species per point count (30 m radius). Values of native birds’ diversity (30 m radius) for each environment and season of (C) Shannon–Wiener Diversity Index (H′) and (D) Simpson’s Diversity Index (D). Error bars show 95% confidence intervals.
Figure 4. Values estimated by GLMMs for each environment and season of (A) average richness of native bird species per point count (50 m radius) and (B) average abundance of native bird species per point count (30 m radius). Values of native birds’ diversity (30 m radius) for each environment and season of (C) Shannon–Wiener Diversity Index (H′) and (D) Simpson’s Diversity Index (D). Error bars show 95% confidence intervals.
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Figure 5. Hierarchical clustering of the similarity degree of native terrestrial bird communities in seasonal streams (SS-1 to SS-6) and residential areas (R-1 to R-6) during summer and winter.
Figure 5. Hierarchical clustering of the similarity degree of native terrestrial bird communities in seasonal streams (SS-1 to SS-6) and residential areas (R-1 to R-6) during summer and winter.
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Figure 6. Estimated average abundance per point count (30 m radius point) according to environment and season from GLMMs for (A) Green-backed Firecrown (S. sephaniodes), (B) Gray-hooded Sierra Finch (P. gayi), (C) Chilean Swallow (T. leucopyga), and (D) White-crested Elaenia (E. albiceps). Error bars represent 95% confidence intervals.
Figure 6. Estimated average abundance per point count (30 m radius point) according to environment and season from GLMMs for (A) Green-backed Firecrown (S. sephaniodes), (B) Gray-hooded Sierra Finch (P. gayi), (C) Chilean Swallow (T. leucopyga), and (D) White-crested Elaenia (E. albiceps). Error bars represent 95% confidence intervals.
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MDPI and ACS Style

Muñoz-Pacheco, C.B.; Gutiérrez, J.C.; Villaseñor, N.R. Contribution of Seasonal Streams to the Conservation of Native and Migratory Birds in a Coastal Region Undergoing Urbanization. Birds 2025, 6, 8. https://doi.org/10.3390/birds6010008

AMA Style

Muñoz-Pacheco CB, Gutiérrez JC, Villaseñor NR. Contribution of Seasonal Streams to the Conservation of Native and Migratory Birds in a Coastal Region Undergoing Urbanization. Birds. 2025; 6(1):8. https://doi.org/10.3390/birds6010008

Chicago/Turabian Style

Muñoz-Pacheco, Catalina B., Javiera C. Gutiérrez, and Nélida R. Villaseñor. 2025. "Contribution of Seasonal Streams to the Conservation of Native and Migratory Birds in a Coastal Region Undergoing Urbanization" Birds 6, no. 1: 8. https://doi.org/10.3390/birds6010008

APA Style

Muñoz-Pacheco, C. B., Gutiérrez, J. C., & Villaseñor, N. R. (2025). Contribution of Seasonal Streams to the Conservation of Native and Migratory Birds in a Coastal Region Undergoing Urbanization. Birds, 6(1), 8. https://doi.org/10.3390/birds6010008

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