Compared Bird Species Richness Research Articles

The importance of old secondary forests for understory birds in the tropical Andes

Deforestation is perhaps the greatest threat to tropical biodiversity. Anyway, extensive areas in the tropics have naturally regenerated and become secondary forests, which might mitigate biodiversity loss. However, evidence about the value of secondary forests for biodiversity conservation is still controversial. To establish the conservation value of secondary forests in the tropical Andes, we compared bird species richness, abundance, and composition between old and mature secondary forests using camera traps for two consecutive years. Our results suggest that old and mature secondary forests are similar in species richness and abundance to mature secondary forests, but these habitats significantly differ in species composition. Old secondary forests harbored some species highly specialized to mature forests (e.g., ant-following insectivorous birds: Myrmeciza longipes, Gymnopithys bicolor, Formicarius analis, and Dendrocincla fuliginosa) that are highly sensitive to habitat disturbance. Additionally, old secondary forests constitute suitable habitat for several species with decreasing populations, which could become of conservation importance in the long run. We consider that old secondary forests surrounded by mature forests can contribute to conserving understory birds, one of the most susceptible groups, negatively affected by tropical forest loss and degradation. Therefore, strategies for habitat biodiversity protection in this region should also include old secondary forests.

Birds on the move in the face of climate change: High species turnover in northern Europe

Species richness is predicted to increase in the northern latitudes in the warming climate due to ranges of many southern species expanding northwards. We studied changes in the composition of the whole avifauna and in bird species richness in a period of already warming climate in Finland (in northern Europe) covering 1,100 km in south–north gradient across the boreal zone (over 300,000 km2). We compared bird species richness and species‐specific changes (for all 235 bird species that occur in Finland) in range size (number of squares occupied) and range shifts (measured as median of area of occupancy) based on bird atlas studies between 1974–1989 and 2006–2010. In addition, we tested how the habitat preference and migration strategy of species explain species‐specific variation in the change of the range size. The study was carried out in 10 km squares with similar research intensity in both time periods. The species richness did not change significantly between the two time periods. The composition of the bird fauna, however, changed considerably with 37.0% of species showing an increase and 34.9% a decrease in the numbers of occupied squares, that is, about equal number of species gained and lost their range. Altogether 95.7% of all species (225/235) showed changes either in the numbers of occupied squares or they experienced a range shift (or both). The range size of archipelago birds increased and long‐distance migrants declined significantly. Range loss observed in long‐distance migrants is in line with the observed population declines of long‐distance migrants in the whole Europe. The results show that there is an ongoing considerable species turnover due to climate change and due to land use and other direct human influence. High bird species turnover observed in northern Europe may also affect the functional diversity of species communities.

The potential of military training areas for bird conservation in a central European landscape

European biodiversity has suffered from serious declines during the past few decades, with alterations of land use practices resulting in a loss of fine-scale habitat heterogeneity being a dominant driver. This heterogeneity was maintained by extensive landscape management, which has gradually been replaced by either intensive exploitation or land abandonment. It has been suggested that military training can generate habitat heterogeneity that may support the existence of species of conservation concern, but studies rigorously testing the real importance of military training areas for biodiversity are lacking. Here we address this issue by analyses of two datasets. First, we compared land cover classes between all large military training areas (MTAs) and surrounding control areas (CAs) of the same size in the Czech Republic using multivariate redundancy analysis. We found that the difference in land cover between MTAs and CAs was significant and represented the strongest gradient in land cover classes: from various farmland and artificial habitats typical for CAs to forest and scrubland-grassland mosaic typical for MTAs. Second, we selected one of these areas and compared bird species richness between the MTA and the nearby CA using generalized linear mixed effects models. We found that the number of species of conservation concern was significantly higher in the MTA than in the CA. With respect to habitats, bird species richness was significantly higher in the MTA than in the CA for open habitats, but not for forest habitats. Our results are thus consistent with the view that military training creates areas that are different from the surrounding landscape in terms of land cover, and that this difference translates to a suitability for species of conservation concern. It is remarkable that the positive influence of military training is confined to open habitats, which are subject to the most intensive military activities and also suffer the highest degree of deterioration in European landscapes.

Switching from monoculture to polyculture farming benefits birds in oil palm production landscapes: Evidence from mist netting data.

Monoculture farming is pervasive in industrial oil palm agriculture, including those RSPO plantations certified as sustainably managed. This farming practice does not promote the maintenance of farmland biodiversity. However, little scientific attention has been given to polyculture farming in oil palm production landscapes. Polyculture farming is likely to increase the floristic diversity and stand structural complexity that underpins biodiversity. Mist nets were used to sample birds at 120 smallholdings in Peninsular Malaysia. At each site, 12 vegetation structure characteristics were measured. We compared bird species richness, abundance, and composition between monoculture and polyculture smallholdings and used predictive models to examine the effects of habitat quality on avian biodiversity. Bird species richness was significantly greater in polyculture than that of monoculture smallholdings. The number of fallen and standing, dead oil palms were also important positive predictors of species richness. Bird abundance was also strongly increased by standing and dead oil palms and decreased with oil palm stand height. Our results indicate that polyculture farming can improve bird species richness in oil palm production landscapes. In addition, key habitat variables that are closely associated with farming practices, such as the removal of dead trees, should and can be managed by oil palm growers in order to promote biodiversity. To increase the sustainability of oil palm agriculture, it is imperative that stakeholders modify the way oil palms are currently planted and managed. Our findings can guide policy makers and certification bodies to promote oil palm production landscapes that will function more sustainably and increase existing biodiversity of oil palm landscapes.

Comparing bird species richness and assemblage composition between montane ash eucalypt forest and cool temperate rainforests—an empirical study from Victoria, south-eastern Australia

Patterns of avian species richness and assemblage composition may change markedly between and within vegetation types. We compared bird species richness and assemblage composition in cool temperate rainforest and Mountain Ash (Eucalyptus regnans) forest in the Central Highlands of Victoria, south-eastern Australia. We quantified the effects of the age of stands of Mountain Ash on the extent of forest-type differences with cool temperate rainforest. We also explored the influence of the shape of stands of cool temperate rainforest on bird species richness and the composition of the bird assemblage. We found no significant differences in bird species richness between cool temperate rainforests and Mountain Ash forest. This result was consistent with subtle differences in the composition of the bird assemblage, with few bird taxa being totally excluded from either of the two forest types. Some species (e.g. Pink Robin (Petroica rodinogaster)) were significantly more likely to be recorded in cool temperate rainforest but were not uncommon in Mountain Ash forest. We found no evidence of significant effects of stand shape in cool temperate rainforest, which was consistent with analyses of bird assemblages given that most species occurred in both forest types. Hence, we uncovered no evidence of specialist taxa confined to cool temperate rainforest.

Are urban bird communities influenced by the bird diversity of adjacent landscapes?

Summary The species diversity of adjacent landscapes influences the conservation or restoration of several animal groups in urban areas, but the effect on birds is unclear. To address this question, we compared bird species richness (BSR) and community composition between periurban (area surrounding the town) and urban (suburban and centre areas) landscapes across three spatial scales. At a large biogeographical scale (temperate and boreal climatic zone), relationships between the BSR of urban areas and their surrounding landscapes were examined in a meta‐analysis of 18 published studies. In general, BSR was negatively correlated with latitude and urbanization. The BSR of suburban and centre landscapes correlated positively with the BSR of periurban landscapes. However, latitudinal effects were also involved, as BSR in urban and periurban landscapes declined as town latitude increased. Similarity indices were low (50%) between periurban and centre bird communities. At a regional scale, we assessed winter bird data from several towns within three regions of temperate and boreal countries (western France, northern Finland and eastern Canada). The type of periurban landscape, number of inhabitants and town diameter did not affect BSR. BSR was similar between the cities of a given biogeographical area. Bird communities were more similar between similar habitat types of different cities than between different habitats of the same city. At a local scale, we tested the influence of proximity to the periurban landscape on BSR in parks of western French towns of different size. Neither BSR nor community similarity changed in relation to the distance of the park from the periurban landscape. Guild composition according to diet and feeding habitat did not vary between urban and periurban locations at regional or local scales. We conclude that, at regional and local scales, urban bird communities are independent of the bird diversity of adjacent landscapes, and that local features are more important than surrounding landscapes in determining BSR. Whatever the biodiversity quality of the periurban landscape, site‐specific actions such as shrub and tree planting, water restoration and increasing vegetation diversity can change bird diversity in towns and improve the quality of human–wildlife contacts.

Avian recolonization of eastern Canadian bogs after peat mining

To evaluate the potential of bog ecosystems to recover following peat mining, we compared bird species richness,abundance, and assemblages and vegetation among naturally revegetated and undisturbed bog sites in southeastern Quebec.Based on mining history, we selected 28 sites (12 natural, 9 abandoned after blockcut extraction, and 7 abandoned after vacuumextraction) in 15 bogs. We estimated percent cover for six vegetation strata in 106 plots with 100 m radius, on which bird pointcounts were conducted in 1993 and 1996. Vegetation structure differed significantly between natural, post-blockcut andpost-vacuum sites. While vegetation cover was almost complete in natural sites, abandoned sites, especially post vacuum, wereless vegetated, even after 20 years. Bird species richness and abundance were similar in natural and post-blockcut sites andboth were higher than in post-vacuum sites. Ten of the 28 species studied in detail responded to site perturbation. Among them,the Palm Warbler was most closely associated with natural sites. Bird communities were closely associated with vegetationstructure. Communities of post-blockcut sites were more similar to those of natural bogs than were bird communities ofpost-vacuum sites. Since the blockcut method of peat mining is no longer economically feasible, we conclude that bog habitatrestoration should be accompanied by a preservation “safety net” area to counteract the lasting effect of vacuum peat mining onbird species assemblages.