Water availability drives aboveground biomass and bird richness in forest restoration plantings to achieve carbon and biodiversity cobenefits

To combat global warming and biodiversity loss, we require effective forest restoration that encourages recovery of species diversity and ecosystem function to deliver essential ecosystem services, such as biomass accumulation. Further, understanding how and where to undertake restoration to achieve carbon sequestration and biodiversity conservation would provide an opportunity to finance ecosystem restoration under carbon markets. We surveyed 30 native mixed‐species plantings in subtropical forests and woodlands in Australia and used structural equation modeling to determine vegetation, soil, and climate variables most likely driving aboveground biomass accrual and bird richness and investigate the relationships between plant diversity, aboveground biomass accrual, and bird diversity. We focussed on woodland and forest‐dependent birds, and functional groups at risk of decline (insectivorous, understorey‐nesting, and small‐bodied birds). We found that mean moisture availability strongly limits aboveground biomass accrual and bird richness in restoration plantings, indicating potential synergies in choosing sites for carbon and biodiversity purposes. Counter to theory, woody plant richness was a poor direct predictor of aboveground biomass accrual, but was indirectly related via significant, positive effects of stand density. We also found no direct relationship between aboveground biomass accrual and bird richness, likely because of the strong effects of moisture availability on both variables. Instead, moisture availability and patch size strongly and positively influenced the richness of woodland and forest‐dependent birds. For understorey‐nesting birds, however, shrub cover and patch size predicted richness. Stand age or area of native vegetation surrounding the patch did not influence bird richness. Our results suggest that in subtropical biomes, planting larger patches to higher densities, ideally using a diversity of trees and shrubs (characteristics of ecological plantings) in more mesic locations will enhance the provision of carbon and biodiversity cobenefits. Further, ecological plantings will aid the rapid recovery of woodland and forest bird richness, with comparable aboveground biomass accrual to less diverse forestry plantations.     

Not all kinds of revegetation are created equal: revegetation type influences bird assemblages in threatened Australian woodland ecosystems

The value for biodiversity of large intact areas of native vegetation is well established. The biodiversity value of regrowth vegetation is also increasingly recognised worldwide. However, there can be different kinds of revegetation that have different origins. Are there differences in the richness and composition of biotic communities in different kinds of revegetation? The answer remains unknown or poorly known in many ecosystems. We examined the conservation value of different kinds of revegetation through a comparative study of birds in 193 sites surveyed over ten years in four growth types located in semi-cleared agricultural areas of south-eastern Australia. These growth types were resprout regrowth, seedling regrowth, plantings, and old growth.Our investigation produced several key findings: (1) Marked differences in the bird assemblages of plantings, resprout regrowth, seedling regrowth, and old growth. (2) Differences in the number of species detected significantly more often in the different growth types; 29 species for plantings, 25 for seedling regrowth, 20 for resprout regrowth, and 15 for old growth. (3) Many bird species of conservation concern were significantly more often recorded in resprout regrowth, seedling regrowth or plantings but no species of conservation concern were recorded most often in old growth. We suggest that differences in bird occurrence among different growth types are likely to be strongly associated with growth-type differences in stand structural complexity.Our findings suggest a range of vegetation growth types are likely to be required in a given farmland area to support the diverse array of bird species that have the potential to occur in Australian temperate woodland ecosystems. Our results also highlight the inherent conservation value of regrowth woodland and suggest that current policies which allow it to be cleared or thinned need to be carefully re-examined.     

Eucalypt plantings on farms benefit woodland birds in south‐eastern Australia

Abstract Most of the original forest and woodland cover on the western slopes of New South Wales and the northern plains of Victoria has been cleared for agriculture (wheat, sheep and cattle) and what remains is highly fragmented and modified by a long history of disturbance. Over the past three decades, native eucalypt trees and shrubs have been planted extensively in a part of this region to provide a range of environmental benefits. Our aim was to determine the extent to which these plantings could improve biological diversity in agricultural landscapes in south‐eastern Australia and to identify the variables influencing their effectiveness. We sampled birds at 120 sites encompassing the range of available patch sizes, stand ages, floristic and structural conditions, and habitat attributes for revegetated areas and remnants of native vegetation, and we compared these to nearby paddocks. Eucalypt plantings were found to provide significant improvements in bird population density compared with cleared or sparsely treed paddocks, and mixed eucalypt and shrub plantings had similar bird communities to remnant native forest and woodland in the region. Birds displayed a strong response to patch size, with both larger (≥5–20 ha) eucalypt plantings and larger (≥5–20 ha) remnants having more species and more individuals per unit area than smaller (<5 ha) patches of these vegetation types. Older (10–25 years) plantings had more bird species and individuals than young (<10 years) plantings. The distance from remnant forest and woodland (habitat connectivity) appeared to be an important variable influencing bird species richness in eucalypt plantings. The main differences were due to the greater numbers of species classified as woodland‐dependent in the larger‐sized patches of plantings and remnants. Eucalypt plantings provided useful habitat for at least 10 declining woodland‐dependent species, notably for the Speckled Warbler, Red‐capped Robin and Rufous Whistler. The Brown Treecreeper and Dusky Woodswallow appeared to be the species most limited by the extent of remnant forest and woodland in the region. Plantings of all shapes and sizes, especially those larger than 5 ha, have an important role to play in providing habitat for many bird species. Restoration efforts are more likely to be successful if eucalypt plantings are established near existing remnant vegetation.     

Can site and landscape‐scale environmental attributes buffer bird populations against weather events?

Projected impacts of climate change on the populations and distributions of species pose a challenge for conservationists. In response, a number of adaptation strategies to enable species to persist in a changing climate have been proposed. Management to maximise the quality of habitat at existing sites may reduce the magnitude or frequency of climate‐driven population declines. In addition large‐scale management of landscapes could potentially improve the resilience of populations by facilitating inter‐population movements. A reduction in the obstacles to species’ range expansion, may also allow species to track changing conditions better through shifts to new locations, either regionally or locally. However, despite a strong theoretical base, there is limited empirical evidence to support these management interventions. This makes it difficult for conservationists to decide on the most appropriate strategy for different circumstances. Here extensive data from long‐term monitoring of woodland birds at individual sites are used to examine the two‐way interactions between habitat and both weather and population count in the previous year. This tests the extent to which site‐scale and landscape‐scale habitat attributes may buffer populations against variation in winter weather (a key driver of woodland bird population size) and facilitate subsequent population growth. Our results provide some support for the prediction that landscape‐scale attributes (patch isolation and area of woodland habitat) may influence the ability of some woodland bird species to withstand weather‐mediated population declines. These effects were most apparent among generalist woodland species. There was also evidence that several, primarily specialist, woodland species are more likely to increase following population decline where there is more woodland at both site and landscape scales. These results provide empirical support for the concept that landscape‐scale conservation efforts may make the populations of some woodland bird species more resilient to climate change. However in isolation, management is unlikely to provide a universal benefit to all species.     

Long‐term mammal and nocturnal bird trends are influenced by vegetation type,weather and climate in temperate woodlands

Many studies have documented the individual effects of variables such as vegetation, long‐term climate and short‐term weather on biodiversity. Few, however, have explicitly explored how interactions among these major drivers can influence species abundance. We used data from a 15‐year study (2002–2017) in the endangered temperate woodlands of south‐eastern Australia to test hypotheses associated with the effects of vegetation type, long‐term climate and short‐term weather on population trajectories of seven species of (largely) nocturnal mammals and birds. Despite prolonged drought conditions, there was a significant increase in the abundance of some species over time (e.g. the Eastern Grey Kangaroo). It is possible that destocking of domestic livestock may have reduced competition with Kangaroos, thereby facilitating increases in abundance. The Common Brushtail Possum and Common Ringtail Possum were significantly less likely to occur in replanted woodlands, possibly because of the paucity of nesting sites. We found no evidence that replanted woodlands are refuges for exotic pest species like the European Rabbit and Red Fox. Short‐ and long‐term rainfall and vegetation type had important independent and combined effects on animal abundance. That is, responses to periods of high short‐term rainfall were dependent on vegetation type and whether sites occurred in long‐term climatically wet versus climatically dry locations. For example, the Red Fox responded positively to high levels of short‐term rainfall, but only at climatically dry sites. Our results highlight the complementary value of different vegetation types across the landscape and the context‐specific responses of animals to short‐term fluctuations in moisture availability. They also underscore the value of long‐term monitoring at a landscape scale for examining how multiple interacting factors influence trends in animal abundance.     

Long-term bird colonization and turnover in restored woodlands

The long-term effectiveness of restored areas for biodiversity is poorly known for the majority of restored ecosystems worldwide. We quantified temporal changes in bird occurrence in restoration plantings of different ages and geometries, and compared observed patterns with a reference dataset from woodland remnants on the same farms as our plantings. Over time, bird species richness remained unchanged in spring but exhibited modest increases in winter. We found that wider plantings supported significantly greater bird species richness in spring and winter than narrow plantings. There was no evidence of a significant interaction between planting width and time. We recorded major temporal changes in the occurrence of a range of individual species that indicated a clear turnover of species as plantings matured. Our results further revealed marked differences in individual species occurrence between plantings and woodland remnants. Life-history attributes associated with temporal changes in the bird assemblage were most apparent in winter survey data, and included diet, foraging and nesting patterns, movement behaviour (e.g. migratory vs. dispersive), and body size. Differences in bird assemblages between plantings of different ages suggest that it is important that farms support a range of age classes of planted woodland, if the aim is to maximize the number of native bird species in restored areas. Our data also suggest that changes in the bird species occupying plantings of different ages can be anticipated in a broadly predictable way based on planting geometry (especially width) and key life-history attributes, particularly movement patterns and habitat and diet specialisation.     

Spatially designed revegetation—why the spatial arrangement of plants should be as important to revegetation as they are to natural systems

The spatial arrangements of plants, both within and between species, play a key role in natural systems and influence many fundamental ecological processes (e.g. survival, competition, facilitation, pollination, and seed dispersal) and ecosystem functions (e.g. habitat value, erosion, water, and nutrient capture). Despite this knowledge, fine‐scale planting arrangements are rarely considered during restoration plantings, yet manipulation of planting designs has the potential to aid the development of resilient and self‐sustaining ecosystems. Here, we outline how the spatial arrangement of plants can influence processes both at the vegetation level and more broadly at the ecosystem level. The review is focused on woodland systems, but also draws on key examples from grassland ecosystems. Following this synthesis, we identify research gaps in the revegetation literature that could usefully be addressed to help develop this understudied field of research. Finally, we outline components of population and community level arrangements (e.g. spacing, aggregation, community composition) that can be considered during restoration plantings—spatially designed revegetation—which are likely to lead to improved ecological outcomes of woodland and grassy woodland revegetation.     

A review and meta‐analysis of the effects of climate change on Holarctic mountain and upland bird populations

Mountain regions are globally important areas for biodiversity but are subject to multiple human‐induced threats, including climate change, which has been more severe at higher elevations. We reviewed evidence for impacts of climate change on Holarctic mountain bird populations in terms of physiology, phenology, trophic interactions, demography and observed and projected distribution shifts, including effects of other factors that interact with climate change. We developed an objective classification of high‐elevation, mountain specialist and generalist species, based on the proportion of their breeding range occurring in mountain regions. Our review found evidence of responses of mountain bird populations to climate (extreme weather events, temperature, rainfall and snow) and environmental (i.e. land use) change, but we know little about either the underlying mechanisms or the synergistic effects of climate and land use. Long‐term studies assessing reproductive success or survival of mountain birds in relation to climate change were rare. Few studies have considered shifts in elevational distribution over time and a meta‐analysis did not find a consistent direction in elevation change. A meta‐analysis carried out on future projections of distribution shifts suggested that birds whose breeding distributions are largely restricted to mountains are likely to be more negatively impacted than other species. Adaptation responses to climate change rely mostly on managing and extending current protected areas for both species already present, and for expected colonizing species that are losing habitat and climate space at lower elevation. However, developing effective management actions requires an improvement in the current knowledge of mountain species ecology, in the quality of climate data and in understanding the role of interacting factors. Furthermore, the evidence was mostly based on widespread species rather than mountain specialists. Scientists should provide valuable tools to assess the status of mountain birds, for example through the development of a mountain bird population index, and policy‐makers should influence legislation to develop efficient agri‐environment schemes and forestry practices for mountain birds, as well as to regulate leisure activities at higher elevations.     

Comparing the recovery of richness,structure, and biomass in naturally regrowing and planted reforestation

The clearing of natural vegetation for agriculture has reduced the capacity of natural systems to provide ecosystem functions. Ecological restoration can restore desirable ecosystem functions, such as creating habitat for animal conservation and carbon sequestration as woody biomass. In order to maintain these beneficial ecosystem functions, restoration projects need to mature into self‐perpetuating communities. Here we compared the ecological attributes of two types of restoration, “active” tree plantings with “passive” natural forest regeneration (“natural regrowth”) to existing remnant vegetation in a cleared agricultural landscape. Specifically, we measured differences between forest categories in factors that may predict future restoration failure or ecosystem collapse: aboveground plant biomass and biomass accrual over time (for regrowing stands), plant density and size class distributions, and diversity of functional groups based on seed dispersal and growth strategy traits. We found that natural regrowth and planted forests were similar in many ecological characteristics, including biomass accrual. Despite this, planted stands contained fewer tree recruit and shrub individuals, which may be due to limited recruitment in plantings. If this continues, these forests may be at risk of collapsing into nonforest states after mature trees senesce. Lower shrub density and richness of mid‐story trees may lead to lower structural complexity in planting plots, and alongside lower richness of fleshy‐fruited plant species may reduce animal resources and animal use of the restored stand. In our study region, natural regrowth may result in restored woodland communities with greater conservation and carbon mitigation value.     

Avian Habitat Preference in Tropical Forest Restoration in Southern Costa Rica

An important question for tropical forest restoration is whether degraded lands can be actively managed to attract birds. We censused birds and measured vegetation structure at 27 stations in young (6–9‐yr old) actively and passively restored pasture and old growth forest at Las Cruces Biological Station in southern Costa Rica. During 481 10‐min point counts, we detected a high diversity—186 species—of birds using the restoration area. Surprisingly, species richness and detection frequency did not differ among habitats, and proportional similarity of bird assemblages to old growth forest did not differ between restoration treatments. Bird detection frequency was instead explained by exotic grass cover and understory stem density—vegetation structures that were not strongly impacted by active restoration. The similarity of bird assemblages in actively and passively restored forest may be attributed to differential habitat preferences within and among feeding guilds, low structural contrast between treatments, or the effect of nucleation from actively restored plots into passively restored areas. Rapid recovery of vegetation in this recently restored site is likely due to its proximity to old growth forest and the lack of barriers to effective seed dispersal. Previous restoration studies in highly binary environments (i.e., open pasture vs. tree plantation) have found strong differences in bird abundance and richness. Our data contradict this trend, and suggest that tropical restoration ecologists should carefully consider: (1) when the benefits of active restoration outweigh the cost of implementation; and (2) which avian guilds should be used to measure restoration success given differential responses to habitat structure.     

Vegetation associations of birds wintering in a California oak woodland

Conditions in wintering areas can have persistent effects throughout the year for bird populations. Most studies, however, are conducted during the breeding season and the non‐breeding ecology of many species remains poorly understood. We assessed vegetation associations of birds wintering in a diverse, well‐structured oak woodland in coastal‐central California. We calculated density estimates for 20 bird species and examined correlations between bird densities and vegetation characteristics as described by a principal components analysis. Ruby‐crowned Kinglets (Regulus calendula) and Hutton's Vireos (Vireo huttoni) were positively associated with vegetation characteristic of dense, floristically diverse woodland with abundant coast live oak (Quercus agrifolia) cover and a structurally complex understory. Conversely, White‐breasted Nuthatches (Sitta carolinensis) and Western Bluebirds (Sialia mexicana) were negatively correlated with dense woodland and occurred at the highest densities on plots with large widely spaced blue oaks (Q. douglasii) and a sparse understory. Thirteen of the remaining 16 species were more abundant in dense woodland patches, but these relationships were not statistically significant. Our results are in agreement with those of previous studies and suggest that evergreen oak trees and a dense understory provide key resources (e.g., cover and food) for some bird species during the winter. However, areas with large widely spaced deciduous oaks are important habitats for other species. We therefore suggest that dense patches of live oaks and shrubs should be retained, but a mosaic of dense and sparse woodland is necessary to accommodate the entire suite of oak‐woodland birds.     

Collapse of an avifauna: climate change appears to exacerbate habitat loss and degradation

Aim  We characterized changes in reporting rates and abundances of bird species over a period of severe rainfall deficiency and increasing average temperatures. We also measured flowering in eucalypts, which support large numbers of nectarivores characteristic of the region.
Location  A 30,000-km² region of northern Victoria, Australia, consisting of limited amounts of remnant native woodlands embedded in largely agricultural landscapes.
Methods  There were three sets of monitoring studies, pitched at regional (survey programmes in 1995–97, 2004–05 and 2006–08), landscape (2002–03 and 2006–07) and site (1997–2008 continuously) scales. Bird survey techniques used a standard 2-ha, 20-min count method. We used Bayesian analyses of reporting rates to document statistically changes in the avifauna through time at each spatial scale.
Results  Bird populations in the largest remnants of native vegetation (up to 40,000 ha), some of which have been declared as national parks in the past decade, experienced similar declines to those in heavily cleared landscapes. All categories of birds (guilds based on foraging substrate, diet, nest site; relative mobility; geographical distributions) were affected similarly. We detected virtually no bird breeding in the latest survey periods. Eucalypt flowering has declined significantly over the past 12 years of drought.
Main conclusions  Declines in the largest woodland remnants commensurate with those in cleared landscapes suggest that reserve systems may not be relied upon to sustain species under climate change. We attribute population declines to low breeding success due to reduced food. Resilience of bird populations in this woodland system might be increased by active management to enhance habitat quality in existing vegetation and restoration of woodland in the more fertile parts of landscapes.     

Height differences in two eucalypt provenances with contrasting levels of aridity

Huge investments are fed into repairing the world's degraded land, placing unparalleled pressure on delivering large quantities of quality seed. One of the most pressing issues is to identify which region to collect seed from and specifically whether local seed has a home‐site advantage, particularly given the pressures of climate change. Recent theoretical recommendations have supported supplementing local seed with seed transferred in an arid‐to‐mesic direction to improve climate resilience of plantings. We tested this recommendation by establishing a reciprocal transplant trial in June 2010 of two seed provenances with contrasting aridity of Eucalyptus socialis, a tree widely used for restoration in Southern Australia. We recorded survival and height over 5 years. The years 2010 and 2011 were particularly wet years at both sites (>1.8 times historical rainfall), but the years 2012–2015 were consistent with long‐term rainfall trends, with the arid site receiving 12–48% less annual rainfall than the mesic site. Only the arid provenance showed a home‐site advantage, and only for height after the two wet years followed by the three drier years. Provenances had similar levels of survival at both sites and did equally well at the mesic site. These results only provide initial evidence to support the recommendation that restoration plantings aiming to incorporate climate resilience should include arid‐to‐mesic transferred seed. Further work is needed to fully explore potential confounding site‐specific effects. Supplementing locally collected seeds with arid‐to‐mesic transferred seed could be important to increase climate resilience of plantings and demands further studies to explore its costs versus benefits.     

Perennial biomass feedstocks enhance avian diversity

Federal mandates to increase biofuel production in North America will require large new tracts of land with potential to negatively impact biodiversity, yet empirical information to guide implementation is limited. Because the temperate grassland biome will be a production hotspot for many candidate feedstocks, production is likely to impact grassland birds, a group of major conservation concern. We employed a multiscaled approach to investigate the relative importance of arthropod food availability, microhabitat structure, patch size and landscape‐scale habitat structure and composition as factors shaping avian richness and abundance in fields of one contemporary (corn) and two candidate cellulosic biomass feedstocks (switchgrass and mixed‐grass prairie) not currently managed as crops. Bird species richness and species density increased with patch size in prairie and switchgrass, but not in corn, and was lower in landscapes with higher forest cover. Perennial plantings supported greater diversity and biomass of arthropods, an important food for land birds, but neither metric was important in explaining variation in the avian community. Avian richness was higher in perennial plantings with greater forb content and a more diverse vegetation structure. Maximum bird species richness was commonly found in fields of intermediate vegetation density and grassland specialists were more likely to occur in prairies. Our results suggest that, in contrast to corn, perennial biomass feedstocks have potential to provide benefits to grassland bird populations if they are cultivated in large patches within relatively unforested landscapes. Ultimately, genetic improvement of feedstock genets and crop management techniques that attempt to maximize biomass production and simplify crop vegetation structure will be likely to reduce the value of perennial biomass plantings to grassland bird populations.     

Bird responses to riparian management of degraded lowland streams in southeastern Australia

We assessed the degree to which fencing, livestock exclusion, and replanting of riparian zones affected avian assemblages in massively cleared landscapes. Measurements were made at three creeks in the southern Murray–Darling Basin in southeastern Australia, each of which had circa 1‐km long treated sections and paired “untreated” circa 1‐km sections, where no fencing, planting, or stock exclusion was done. We measured the change in vegetation characteristics and abundances of native birds for up to 8 years after works were completed. Prior to data collection, we developed expected responses of bird species based on the anticipated time‐courses of change in vegetation structure. We used hierarchical Bayesian models to explore the effects of the management actions, and to account for within‐site variation in vegetation characteristics. There were major changes in vegetation structure (reductions in bare ground and increases in shrubs and tree recruitment) but avian responses generally were small and not as expected. There are at least four possible reasons for the limited avian responses: (1) there has been a long‐term decline in woodland birds across the region; (2) the study was conducted during the longest drought in the instrumental record in the study region; (3) the total amount of replanted vegetation was small in a massively denuded region; and (4) monitoring may have been over too short a term to detect responses to longer‐term changes in structural vegetation.     

Exploring co‐occurrence of closely‐related guild members in a fragmented landscape subject to rapid transformation

Quantifying biotic responses to landscape transformation is a major research focus. Most past studies have explored co‐occurrence of entire communities of a given group (e.g. birds) within largely intact ecosystems or over a limited time‐frame. By contrast, here we use data from a 15 yr experimental study, to explore intra‐guild co‐occurrence of six closely‐related and functionally‐similar sets of birds within 55 woodland fragments. Areas surrounding these remnants are undergoing transformation from grazed paddocks to Pinus radiata plantations, leading to a novel assemblage of forest and woodland birds. We sought to determine if the occurrence of a given species in a guild influenced the occurrence of other closely‐related species in that guild, and through this relationship whether there was evidence of co‐occurrence between species. After controlling for environmental and habitat variables which can affect species occurrence like time since commencement of landscape transformation, patch size and vegetation type, we found the occurrence of a given species was influenced by the occurrence of a closely‐related species in the same guild. Co‐occurrence varied among bird guilds and included: 1) positive co‐occurrence in which occurrence of one species within fragments positively affected the occurrence of another closely‐related guild member (e.g. eastern and crimson rosellas); and 2) negative co‐occurrence in which the occurrence of one species was negatively associated with the occurrence of another within the same guild (e.g. willie wagtail and grey fantail). We also identified interactions between patch size and species recording frequency within members of two guilds. For example, modelling of conditional recording frequency revealed the eastern rosella increased with increasing recordings of the crimson rosella in large patches, but decreased with increasing recordings of the crimson rosella in small patches. Our results provide empirical evidence of co‐occurrence among guild members and underscore the complexity of biotic responses to landscape transformation.     

Site vegetation characteristics are more important than landscape context in determining bird assemblages in revegetation

The effectiveness of revegetation in providing habitat for fauna is expected to be determined both by within‐site factors and attributes of the landscape in which a revegetation site occurs. Most studies of fauna in revegetation have been conducted in landscapes that have been extensively cleared, modified or fragmented, and in Australia, predominantly in the southern temperate zone. We investigated how within‐site vegetation attributes and landscape context attributes were related to bird species richness and composition in a chronosequence of post‐mining rehabilitation sites within an otherwise intact landscape in tropical northern Australia. Our working hypothesis was that bird species richness in rehabilitating sites would be positively related to site vegetation structure and landscape context including (1) proximity to woodland and (2) the proportion of woodland within a 500‐m buffer of rehabilitation sites. Within each of 67 sites, we sampled vegetation once and surveyed for birds eight times over 16 months. Landscape context variables were calculated using GIS. There were large differences between bird assemblages of woodland and rehabilitation sites and between age classes of rehabilitation. Bird assemblages were strongly related to site vegetation attributes across all rehabilitation sites. Proximity to woodland was only related to bird assemblages in rehabilitation sites older than 4 years old. We conclude that the relative importance of landscape context and site variables at any point in time will be a function of how closely vegetation within the revegetation site matches the habitat resource requirements of individual species.     

Can the effect of species ecological traits on birds' altitudinal changes differ between geographic areas?

The altitudinal distribution of mountain birds has recently changed following different patterns in space and time, probably due to the variability of the ongoing environmental processes. Although several studies have highlighted the effect of climate warming in affecting birds altitudinal responses, in the Alps, land abandonment and the consequential forest regrowth may have played a fundamental role.We applied the response curve shape method to investigate changes in the altitudinal distribution of breeding birds over a ten-year period in two different alpine areas (Central and Western Italian Alps) and we performed a log-linear analysis to depict the differential responses of species grouped according to their breeding habitat preferences.The patterns of change remarkably differed according to species ecological traits and between mountain areas. We did not highlight clear altitudinal changes in the Central Alps for any ecological groups, while in the Western Alps, woodland birds showed an expansion pattern and grassland birds suffered a retraction pattern. Since the two alpine areas did not suffer a significant temperature increase, but experienced different woodland cover dynamics, we believe that forest regrowth played a key role in shaping the different bird altitudinal responses between the two sites.Our findings illustrate the effect of ecological traits in shaping altitudinal changes and the role of local environmental factors in affecting spatial variation. Particularly, we strongly suggest considering woodland cover expansion as a key driver of bird altitudinal changes in alpine areas.     

Are protected areas maintaining bird diversity?

Evaluating the effectiveness of protected areas for sustaining biodiversity is crucial to achieving conservation outcomes. While studies of effectiveness have improved our understanding of protected‐area design and management, few investigations (< 5%) have quantified the ecological performance of reserves for conserving species. Here, we present an empirical evaluation of protected‐area effectiveness using long‐term measures of a vulnerable assemblage of species. We compare forest and woodland bird diversity in the Australian Capital Territory over 11 yr on protected and unprotected areas located in temperate eucalypt woodland and matched by key habitat attributes. We examine separately the response of birds to protected areas established prior to 1995 and after 1995 when fundamental changes were made to regional conservation policy. Bird diversity was measured in richness, occurrence of vulnerable species, individual species trajectories and functional trait groups. We found that protected areas were effective in maintaining woody vegetation cover in the study region, but were less effective in the protection of the target bird species assemblage. Protected areas were less species rich than unprotected areas, with significant declines in richness across sites protected prior to 1995. Small, specialised and vulnerable species showed stronger associations with unprotected areas than protected areas. Our findings indicate that recently established reserves (post‐1995) are performing similarly to unprotected woodland areas in terms of maintaining woodland bird diversity, and that both of these areas are more effective in the conservation of woodland bird populations than reserves established prior to 1995. We demonstrate that the conservation value of protected areas is strongly influenced by the physical characteristics, as well as the landscape context, of a given reserve and can diminish with changes in surrounding land use over time. Both protected areas and off‐reserve conservation schemes have important roles to play in securing species populations.     

Impacts of clearing,fragmentation and disturbance on the bird fauna of Eucalypt savanna woodlands in central Queensland,Australia

Abstract This study reports on the responses of bird assemblages to woodland clearance, fragmentation and habitat disturbance in central Queensland Australia, a region exposed to very high rates of vegetation clearance over the last two to three decades. Many previous studies of clearing impacts have considered situations where there is a very sharp management contrast between uncleared lands and cleared areas: in this situation, the contrast is more muted, because both cleared lands and uncleared savanna woodlands are exposed to cattle grazing, invasion by the exotic grass Cenchrus ciliaris and similar fire management. Bird species richness (at the scale of a 1‐ha quadrat) was least in cleared areas (8.1 species), then regrowth areas (14.6 species), then uncleared woodlands (19.9 species). Richness at this scale was unrelated to woodland fragment size, connectivity or habitat condition; but declined significantly with increasing abundance of miners (interspecifically aggressive colonial honeyeaters). At whole of patch scale, richness increased with fragment size and decreased with abundance of miners. This study demonstrates complex responses of individual bird species to a regional management cocktail of disturbance elements. Of 71 individual bird species modelled for woodland fragment sites, the quadrat‐level abundance of 40 species was significantly related to at least one variable representing environmental position (across a rainfall gradient), fragment condition, fragment size and/or connectivity. This study suggests that priorities for conservation management include: cessation of broad‐scale clearing; increased protection for regrowth (particularly where this may bolster connectivity and/or size of woodland fragments); control of miners; maintenance of fallen woody debris in woodlands; increase in fire frequency; and reduction in the incidence of grazing and exotic pasture grass.