Landscape structure and bird species richness: implications for conservation in rural areas between natural parks (original) (raw)
Related papers
Landscape and Urban Planning, 2008
This paper explores the association of a set of land variables with bird species richness in the area of Barcelona, subgrouped into nesting and wintering, and three classes of conservation concern: total species, species of European Concern (SPEC 2 and 3), and species included in the Birds Directive. It also analyzes the association of the species richness among these groups, and compares their values inside and outside of the protected areas. Bird data were obtained by field sampling within 1700 l km × l km UTM grid cells, which were sampled between 1990 and 1998 until the entire study area had been assessed. For each cell, derivatives of the following variables were calculated: climate, relief, landscape, geographic position, and human settlement. Relative forest and cropland covers and landscape diversity were the main positive correlates of total species richness, while the average elevation was the prime negative correlate for wintering species. SPEC and Birds Directive species richness were negatively related to forest and urban covers, and positively related to that of croplands and shrublands-grasslands. The species richness of birds of no conservation concern (non-listed) was generally positively related to those of SPEC and Birds Directive species, regardless of whether they were wintering or nesting. There was significantly more bird richness outside the reserves in all but one of the classes of conservation concern-nesting Birds Directive. The study confirms the importance of open habitats and heterogeneous rural landscapes for bird species richness in the study area, and provides conservation guidelines based on regional policy.
Background: Urbanisation is a dominant geographical trend and an important component of global change, with unprecedented implications for socio‑economic, cultural and environmental characteristics. However, green areas, including original fragments, can help to conserve native diversity, improving the functioning of these artificial systems in the long term. Urban areas can still provide habitats usable by wild birds, however the structural charac‑ teristics of the habitat formed by different types of green area differ, and therefore dissimilar bird diversities are to be expected. The object of this study was to characterise the α and β diversities of birds in different green areas and to analyse how diversity relates to ten variables that characterise the habitat. Methods: We studied the green areas in the city of Temuco, southern Chile (Park, Square and Median strips of main streets), evaluating the variables: (a) surface area, (b) vegetation, (c) estimated human impact as the proportions of vegetation and bare soil by area, and the vehicle traffic. The bird assemblage structures were characterised by α (intra‑ environment) diversity and β diversity (between environments) and the statistical analysis identified the environmen‑ tal variables related with the presence and abundance of birds. A statistical model was constructed to describe the contribution of the variables to bird diversity. Results: We found significant differences between the diversity of bird species in the three types of green area. The β showed medium to high similarity between the different study units. There was a negative correlation with bare soil areas; the correlations with vehicle flow, plant structure and tree and shrub cover were not significant, meaning that these variables did not explain the variation in the richness of bird species between the green areas. However the surface area did explain this variation presenting a positive potential relation. There was also a high correlation with the origin (native) of shrub species. Conclusions: The bird diversity varied significantly according to the type of urban green area. The environmental variables presenting significant correlations with bird diversity were: surface area, native species of shrub stratum, shrub cover, and bare soil area. The best multiple regression model showed that the three most important variables for bird diversity are the surface area of the green area, the cover of the shrub stratum and the presence of native shrub species.
Biodiversity and Conservation, 2011
Identifying spatial patterns in species diversity represents an essential task to be accounted for when establishing conservation strategies or monitoring programs. Predicting patterns of species richness by a model-based approach has recently been recognised as a significant component of conservation planning. Finding those environmental predictors which are related to these patterns is crucial since they may represent surrogates of biodiversity, indicating in a fast and cheap way the spatial location of biodiversity hotspots and, consequently, where conservation efforts should be addressed. Predictive models based on classical multiple linear regression or generalised linear models crowded the recent ecological literature. However, very often, problems related with spatial autocorrelation in observed data were not adequately considered. Here, a spatially-explicit data-set on birds presence and distribution across the whole Tuscany region was analysed. Species richness was calculated within 1 9 1 km grid cells and 10 environmental predictors (e.g. altitude, habitat diversity and satellite-derived landscape heterogeneity indices) were included in the analysis. Integrating spatial components of variation with predictive ecological factors, i.e. using geostatistical models, a general model of bird species richness was developed and used to obtain predictive regional maps of bird diversity hotspots. A meaningful subset of environmental predictors, namely habitat productivity, habitat heterogeneity, combined with topographic and geographic information, were included in the final geostatistical model. Conservation strategies based on the predicted hotspots as well as directions for increasing sampling effort efficiency could be extrapolated by the proposed model.
The rapid expansion of agriculture in recent decades in Argentina poses challenges for conservation of bird diversity because many species that provide ecosystems services to agriculture are sensitive to these changes. Several regional drivers, such as climatic conditions or production systems, could affect bird’s persistence and modify distribution patterns. We evaluated relationships between bird occupancy and richness and land use-cover, and explored temporal trends in three sub-regions based on predominant agricultural production activities in an area comprising 255,000 km2 of Espinal and Pampas ecoregions, which contains the main agricultural areas in Argentina. Between 2003-2012, we conducted yearly surveys using point counts along secondary roads in two heterogeneous sub-regions, one with native forest, agriculture and cattle activities (“Entre Rios”, n=120 sites) and another with a combination grazing grasslands and crops (“Inland Pampas”, n=168); and an area with a predominance of annual crops(mostly soybean and corn, “Soybean”,n=192). We accounted for imperfect detection using Bayesian hierarchical, multi-species and multi-season occupancy models. Richness, species occupancy and temporal trends differed between subregions. A higher number of species were negatively affected by soybean proportion in the Soybean sub-region (Beta community -0.701, CRI95% (-1.39;-0.04)). Landscape heterogeneity in Entre Rios and Inland benefit birds, mitigating agricultural land use effects (Beta community -0.201 (CRI95% -0.75;0.35); -0.24 (CRI95% -0.87;0.39)). Richness was low and stable in Inland, while in Entre Ríos, increased in time. We found no clear trends in richness in the Soybean sub-region. Our results provide baseline information for decision making, to reconcile bird conservation with agriculture at regional scales.
Ecología Austral, 2020
The páramo ecosystem harbors a high concentration of restricted range and threatened bird species. However, human modifications to the high Andean landscape have generated habitat loss and fragmentation throughout this ecosystem. Therefore, protected areas in this region are a priority for biodiversity conservation. Buffer zones around protected areas aim to reduce perturbation within them. However, these areas are still not exempt from sources of stress. We used abundance and diversity of birds, recorded by walking transects, in order to compare the community composition occurring in protected areas and adjacent buffer zones in a hotspot of diversity and endemism: the Macizo del Cajas Biosphere Reserve, in the southern high-Andes of Ecuador. The bird community did not vary in its composition between protected areas and buffer zones. However, the habitat characteristics explained differences in the presence and abundance of trophic guilds. Particularly, increasingly heterogeneous páramo grassland with greater woody plant cover and less intervention explained a greater presence and abundance of more specialized trophic guilds such as nectarivores in shrubs and aerial insectivores in trees and shrubs. We conclude that there are heterogeneous páramo habitats in buffer zones that should be considered in more formal conservation planning to maintain the diversity of specialized birds and therefore functionality of the páramo grassland ecosystem. [Keywords: páramo grassland, Macizo del Cajas Biosphere Reserve, elevation, trophic guilds, specialist birds] R������. La heterogeneidad del hábitat, en lugar de los límites de las áreas protegidas, influye en las comunidades de aves de una reserva de biosfera Andina. El ecosistema de páramo alberga una alta concentración de especies de aves de rango restringido y amenazadas. Sin embargo, las modificaciones humanas al paisaje altoandino han generado pérdida y fragmentación de hábitat en todo este ecosistema. Por lo tanto, las áreas protegidas en esta región son prioritarias para la conservación de la biodiversidad. Las zonas de amortiguamiento en los alrededores de las áreas protegidas tienen por objeto reducir las perturbaciones en éstas; sin embargo, no están exentas de fuentes de estrés. La abundancia y la diversidad de aves, registradas en transectas, se usó para comparar la composición de la comunidad entre áreas protegidas y zonas de amortiguamiento en un hotspot de diversidad y endemismo: la Reserva de la Biósfera del Macizo del Cajas, en los altos Andes del sur del Ecuador. La comunidad de aves no varió en su composición entre las áreas protegidas y las zonas de amortiguamiento. No obstante, las características del hábitat sí explicaron diferencias en la presencia y abundancia de grupos tróficos. En particular, el incremento en la heterogeneidad del páramo, con mayor cobertura de plantas leñosas y menos intervención, explicó una mayor presencia y abundancia de gremios tróficos especializados, tales como nectarívoros en arbustos e insectívoros aéreos en árboles y arbustos. En conclusión, hay hábitats heterogéneos de páramo, en zonas de amortiguamiento, que deben considerarse en una planificación de conservación más formal para mantener la diversidad de aves especialistas y, por lo tanto, la funcionalidad del ecosistema de páramo herbáceo. [Palabras clave: páramo herbáceo, Reserva de la Biósfera Macizo del Cajas, elevación, gremios tróficos, aves especialistas]
Bird community responses along urban–rural gradients: Does the size of the urbanized area matter?
Landscape and Urban Planning, 2009
Human settlements have a strong influence on bird communities. To explore the size effect of the urbanized area in avian community structure, we examined changes in species richness, composition and abundance along urban-rural gradients of different extensions. We measured land-cover variables and surveyed birds along nine urban-rural gradients in the Pampean region of Argentina. In towns over 7000 inh, increasing constructed area was negatively related to species richness. In towns over 13 000 inh, the abundance of native species decreased towards the urban core whereas total abundance increased, decreased or remained constant depending on town characteristics. In villages (<2000 inh), small (2000-14000 inh) and large towns (>60000 inh), there was a constant representation of the rural community composition along gradients. In towns of intermediate sizes (>14 000-60 000 inh), species composition was more similar to that from the rural zone as this zone was approached. Similarity between both urban-core and peripheral points and the rural zone decreased with increasing gradient extension. It appears to be a size threshold for community sensitivity to urbanization below which the impact on community attributes is insignificant; increasing urbanization above the threshold level had pronounced effects on bird assemblages. Research approaches separating responses of native and exotic species to urbanization enhance our understanding to favor native birds and quality of urban bird communities. The size of the urbanized area is a key factor in policies designed to improve ecosystem health and human interactions with nature.
Ardeola, 2010
La fisonomia y composicion floristica de la vegetacion conforman la estructura de las comunidades de aves a escala local. Sin embargo, la utilidad de estos rasgos para identificar areas apropiadas para las aves puede quedar oscurecida por la accion de otros factores, como la altitud, el clima y la estructura del paisaje a escala regional. Estos factores actuan a grandes escalas espaciales (en gradientes latitudinales), pero tambien a escalas menores (regiones montanosas). En este trabajo se explora la influencia de la topografia y la vegetacion sobre las comunidades de aves nidificantes e invernantes en la �ecorregion de bosque mixto cantabrico� (Espana), un area donde muchos pajaros forestales palearticos alcanzan el borde suroeste de su area de distribucion. El trabajo se realizo en nueve bosques extensivos semi-naturales localizados en la ladera norte de la cordillera Cantabrica, con alturas comprendidas entre 400 m y 1.300 m. Los pajaros se censaron en 78 transectos lineales de ...
Semiarid Mediterranean areas patchily forested with Pinus halepensis Mill. are often affected by urbanisation plans, which influence the conservation of biodiversity in the remaining fragments. We assessed forest biodiversity in eleven Pinus halepensis patches of the municipality of Murcia (SE Spain), on the basis of the abundance, richness and conservation value of birds and woody flora. Under the hypothesis that biodiversity is conditioned by pine density, modulated by other patch features (age, physical substrate, surrounding land uses), mixed regression models were used to relate biodiversity indicators with environmental gradients, detected through principal component analyses (PCAs) performed on three sets of variables: landscape (L); habitat structure (H); and, stand development (S). PCA-L related patch size and connectivity to the abundance of typical woodland birds and to floral and bird species richness. PCA-H related shrub cover associated with Sylvia melanocephala Gmelin., to rock and dry grassland cover, a feature of moderately disturbed areas preferred by Lanius senator L. PCA-S associated taller trees and better physical conditions with canopy dwelling and soil probing bird species, respectively. The bird or plant conservation value of patches did not generally match their protection status, which was confirmed by the analysis of a larger sample of 36 natural patches. A negative relationship between floristic value and pine density suggests that reducing the density of reforestations can lead to more diverse and self-sustaining wooded formations. In contrast, conservation value for birds did not decrease with reforestation, stressing the need to use ornithological and floristic indexes as complementary assessment tools. The results seem useful for building a municipal network of reserves connecting higher status protected areas.
Biodiversity in cultural landscapes: influence of land use intensity on bird assemblages
Landscape Ecology, 2015
Context Land use changes and intensification have been amongst the major causes of the ongoing biodiversity decline in Europe. A better understanding and description of how different levels of land use intensity affect biodiversity can support the planning and evaluation of policy measures. Objectives Our study investigates how land userelated landscape characteristics affect bird diversity, considering different spatial scales and species groups with characteristic habitat use. Methods We used breeding bird census data from 2693 observation points along 206 transects and applied a random effects hurdle model to describe the influence of the landscape characteristics altitude, forest proportion, patch density, land cover diversity, and land use intensity on avian species richness. Results Land use intensity and related landscape characteristics formed an important explanatory variable for bird richness. Increasing land use intensity was accompanied by a decrease in bird species richness. While forest bird richness decreased with a decreasing amount of forest cover, farmland species richness increased. This led to a bird diversity peak in extensively used semi-open landscapes. The influence of land cover diversity on species richness was small. Increasing patch density had positive effects on forest birds, but affected farm birds negatively. The strongest correlation between land use-based indicators and bird diversity was determined using spatial indicators at a close range around observation points (100-500 m radius). Conclusions Our results assist interpretation of the Pan-European Common Bird Indices and emphasize the importance of using multifaceted and thoroughly selected indicators in the context of biodiversity monitoring and decision-making support.