Correlation between stand structure and ground vegetation: an analytical approach

The effect of stand structure on the diversity of the forest's ground vegetation was examined based on data on permanent sample plots collected in the northern parts of North-Carelia, eastern Finland. Different ordination methods (DCA, GNMDS, LNMDS, and HMDS) were used together with the TWINSPAN classification method. The aim was to construct a basis for classifying forests with respect to the biodiversity of the forest vegetation. Fertility and stand age showed the strongest correlation with the variation in ground vegetation. Other important factors were basal area, tree species composition, and crown cover. These variables were important in the division of the sample plots into different classes. According to the diversity indices, species diversity was at its highest in young stands on fertile forest sites. As a result, twenty-one different classes were formed based on the relative abundance of understorey species. The variables with the highest correlation were used to describe the stand structure in these classes.     

Stratification of density in dry deciduous forest using satellite remote sensing digital data—An approach based on spectral indices

Forest density expressing the stocking status constitutes the major stand physiognomic parameter of Indian forest. Density and age are often taken as surrogate to structural and compositional changes that occur with the forest succession. Satellite remote sensing spectral response is reported to provide information on structure and composition of forest stands. The various vegetation indices are also correlated with forest canopy closure. The paper presents a three way crown density model utilizing the vegetation indices viz., advanced vegetation index, bare soil index and canopy shadow index for classification of forest crown density. The crop and water classes which could not be delineated by the model were finally masked from normalized difference vegetation index and TM band 7 respectively. The rule based approach has been implemented for land use and forest density classification. The broad land cover classification accuracy has been found to be 91.5%. In the higher forest density classes the classification accuracy ranged between 93 and 95%, whereas in the lower density classes it was found to be between 82 and 85%.     

The Role of Landscape Patterns of Habitat Types on Plant Species Diversity of a Tropical Forest in Mexico

The relationships among landscape characteristics and plant diversity in tropical forests may be used to predict biodiversity. To identify and characterize them, the number of species, as well as Shannon and Simpson diversity indices were calculated from 157 sampling quadrats (17,941 individuals sampled) while the vegetation classes were obtained from multi-spectral satellite image classification in four landscapes located in the southeast of Quintana Roo, Mexico. The mean number of species of trees, shrubs and vines as well as the mean value of the total number of species and the other two diversity indices were calculated for four vegetation classes in every one of the four landscapes. In addition, the relationships between landscape patterns metrics of patch types and diversity indices were explored. The multiple statistical analyses revealed significant predictor variables for the three diversity indices. Moreover, the shape, similarity and edge contrast metrics of patch types might serve as useful indicators for the number of species and the other two diversity variables at the landscape scale. Although the association between the three diversity indices and patch types metrics showed similar behavior, some differences were appreciated. The Shannon diversity index, with its greater sensitivity to rare species, should be considered as having a greater importance in interpretation analysis than Simpson index.     

Compositional gradients in the forest vegetation of Finland

Abstract. Compositional gradients of forest vegetation in Finland were determined using detrended correspondence analysis, and ecologically interpreted with regression analysis. The data were collected in association with the 8th National Forest Inventory, and they comprised 1514 samples and 472 species, covering the whole forested land area of Finland. In the ordination space the first, very stable axis (DCA1) was much stronger than the following three, more unstable axes (DCA2 - 4). Site fertility (reflected by the forest site type series) and latitude had strongest covariation with the ordination space, followed by a number of variables primarily related to forest age or tree stand volume. Fertility variables were most closely parallel with DCA1, latitudinal ones with DCA1 and DCA2, and successional variables with DCA3. The results indicate that compositional overlap of sites classified into different Caj ander site types is considerable.     

Avian species richness in relation to intensive forest management practices in early seral tree plantations

Background

Managers of landscapes dedicated to forest commodity production require information about how practices influence biological diversity. Individual species and communities may be threatened if management practices truncate or simplify forest age classes that are essential for reproduction and survival. For instance, the degradation and loss of complex diverse forest in young age classes have been associated with declines in forest-associated Neotropical migrant bird populations in the Pacific Northwest, USA. These declines may be exacerbated by intensive forest management practices that reduce hardwood and broadleaf shrub cover in order to promote growth of economically valuable tree species in plantations.

Methodology and Principal Findings

We used a Bayesian hierarchical model to evaluate relationships between avian species richness and vegetation variables that reflect stand management intensity (primarily via herbicide application) on 212 tree plantations in the Coast Range, Oregon, USA. Specifically, we estimated the influence of broadleaf hardwood vegetation cover, which is reduced through herbicide applications, on bird species richness and individual species occupancy. Our model accounted for imperfect detection. We used average predictive comparisons to quantify the degree of association between vegetation variables and species richness. Both conifer and hardwood cover were positively associated with total species richness, suggesting that these components of forest stand composition may be important predictors of alpha diversity. Estimates of species richness were 35–80% lower when imperfect detection was ignored (depending on covariate values), a result that has critical implications for previous efforts that have examined relationships between forest composition and species richness.

Conclusion and Significance

Our results revealed that individual and community responses were positively associated with both conifer and hardwood cover. In our system, patterns of bird community assembly appear to be associated with stand management strategies that retain or increase hardwood vegetation while simultaneously regenerating the conifer cover in commercial tree plantations.     

广东中西部桉树人工林植物多样性与林龄和土壤因子的关系

以位于广东省中西部的高要市桉树人工林林下植被群落为研究对象,对不同龄级林分物种多样性进行比较分析,采用典范对应分析(CCA)方法进行排序并通过相关分析,对物种分布和多样性与土壤因子的关系进行了研究。结果表明,每龄级24块样地充足,从第9块样地开始不同龄级的物种数目出现一定程度的差异。桉树林分样地中共有136种植物,隶属54科107属,灌木层的种类最多,但以草本层物种为优势种。不同龄级林分之间物种多样性差异不显著,但1—2年生林分低于2—4年生和5—6年生两个龄级;3—4年生的Shannon指数、Simpson指数和丰富度最高。对植被物种的分布,土壤中有机质、全磷、全钾和容重的影响明显,pH值也有一定程度作用,而对物种多样性,pH值和全氮是最为稳定的影响因子。     

How does forest landscape structure explain tree species richness in a Mediterranean context?

Although the strong relationship between vegetation and climatic factors is widely accepted, other landscape composition and configuration characteristics could be significantly related with vegetation diversity patterns at different scales. Variation partitioning was conducted in order to analyse to what degree forest landscape structure, compared to other spatial and environmental factors, explained forest tree species richness in 278 UTM 10 × 10 km cells in the Mediterranean region of Catalonia (NE Spain). Tree species richness variation was decomposed through linear regression into three groups of explanatory variables: forest landscape (composition and configuration), environmental (topography and climate) and spatial variables. Additionally, the forest landscape characteristics which significantly contributed to explain richness variation were identified through a multiple regression model. About 60% of tree species richness variation was explained by the whole set of variables, while their joint effects explained nearly 28%. Forest landscape variables were those with a greater pure explanatory power for tree species richness (about 15% of total variation), much larger than the pure effect of environmental or spatial variables (about 2% each). Forest canopy cover, forest area and land cover diversity were the most significant composition variables in the regression model. Landscape configuration metrics had a minor effect on forest tree species richness, with the exception of some shape complexity indices, as indicators of land use intensity and edge effects. Our results highlight the importance of considering the forest landscape structure in order to understand the distribution of vegetation diversity in strongly human-modified regions like the Mediterranean.     

广州典型风水林碳密度特征

以广州市典型风水林为对象,对其生态系统全组分碳储量及其分配格局进行调查和估算,研究碳密度特征及其影响因素。结果显示：风水林生态系统平均碳密度为（259.17±69.67）t/hm²,其中,植被碳密度为（194.04±54.07）t/hm²（占74.9%）（其中以乔木层占绝对优势,达90%以上）,土壤碳密度为（65.13±19.30）t/hm²（占25.1%）;植被和土壤碳密度之间呈显著正相关（P<0.05）;不同优势种类的风水林碳密度差异较大,以米槠（Castanopsis carlesii（Hemsl.）Hayata.）为优势的林分碳密度最大（310.57±62.65 t/hm²）。结果表明影响风水林碳密度的主要因子是林分胸高断面积、林分密度、土壤容重和土壤碳含量,其中,风水林碳密度与胸高断面积、土壤容重和土壤碳含量呈显著正相关,与林分密度呈显著负相关,与植物多样性无显著相关。研究结果对南亚热带林分改造和碳汇林营造具有重要科学意义。     

The interplay of plant and animal disease in a changing landscape: the role of sudden aspen decline in moderating Sin Nombre virus prevalence in natural deer mouse populations

We examined how climate-mediated forest dieback regulates zoonotic disease prevalence using the relationship between sudden aspen decline (SAD) and Sin Nombre virus (SNV) as a model system. We compared understory plant community structure, small mammal community composition, and SNV prevalence on 12 study sites within aspen forests experiencing levels of SAD ranging from <10.0% crown fade to >95.0% crown fade. Our results show that sites with the highest levels of SAD had reduced canopy cover, stand density, and basal area, and these differences were reflected by reductions in understory vegetation cover. Conversely, sites with the highest levels of SAD had greater understory standing biomass, suggesting that vegetation on these sites was highly clustered. Changes in forest and understory vegetation structure likely resulted in shifts in small mammal community composition across the SAD gradient, as we found reduced species diversity and higher densities of deer mice, the primary host for SNV, on sites with the highest levels of SAD. Sites with the highest levels of SAD also had significantly greater SNV prevalence compared to sites with lower levels of SAD, which is likely a result of their abundance of deer mice. Collectively, results of our research provide strong evidence to show SAD has considerable impacts on vegetation community structure, small mammal density and biodiversity and the prevalence of SNV.     

Nuovi reperti di intersessualità nelle Cucurbitacee

Abstract

The aim of this paper is to investigate differences in plant species composition between managed and unmanaged forests, and to assess if these difference give rise to a higher plant diversity in the unmanaged forest. Furthermore our aim is to relate forest structure to differences in plant species composition, identifying the structural attributes more strongly related to the unmanaged forest vegetation. We compared an old-growth forest and a managed highforest in the Abruzzo Lazio and Molise National Park (Central Italy). Plant species composition and diversity, deadwood components and live structure have been analyzed. We used permutational multivariate analysis of variance to test the response of species composition to management factor; furthermore, we compared species richness and beta diversity. Redundancy analysis has been used to relate plant species abundances to structural variables; the importance of dead and living wood components has been compared through variation partitioning. Plant species composition proved to be significantly different in the two sites, and the old-growth stand showed a higher plant diversity. From a structural point of view, we found differences especially in the amount and quality of deadwood, and in the diameter class distribution. These variables are also the most important in determining the old-growth stand plant species composition according to redundancy analysis. Variation partitioning confirmed the greater importance of the deadwood variables. Our results suggest that including deadwood surveys in traditional forest inventories could help in finding forests with both structural and floristic old-growth properties to be considered in conservation programmes. The imitation of natural dynamics, through the creation of gaps avoiding deadwood removal, could be an effective strategy for restoring old-growth conditions, also in terms of plant diversity.     

Do exotic pine plantations favour the spread of invasive herbivorous mammals in Patagonia?

Changes in land use patterns and vegetation can trigger ecological change in occupancy and community composition. Among the potential ecological consequences of land use change is altered susceptibility to occupancy by invasive species. We investigated the responses of three introduced mammals (red deer, Cervus elaphus; wild boar, Sus scrofa; and European hare, Lepus europaeus) to replacement of native vegetation by exotic pine plantations in the Patagonian forest‐steppe ecotone using camera‐trap surveys (8633 trap‐days). We used logistic regression models to relate species presence with habitat variables at stand and landscape scales. Red deer and wild boar used pine plantations significantly more frequently than native vegetation. In contrast, occurrence of European hares did not differ between pine plantations and native vegetation, although hares were recorded more frequently in firebreaks than in plantations or native vegetation. Presence of red deer and wild boar was positively associated with cover of pine plantations at the landscape scale, and negatively associated with mid‐storey cover and diversity at the stand scale. European hares preferred sites with low arboreal and mid‐storey cover. Our results suggest that pine plantations promote increased abundances of invasive species whose original distributions are associated with woodlands (red deer and wild boar), and could act as source or pathways for invasive species to new areas.     

Simulation of multidimensional community patterns: towards a comprehensive model

Ecological gradients in the field layer of southern boreal forests in South Finland were studied in relation to the dominant tree species and the age of forest stands. The data are from a systematic sample of 529 plots from an area of 150 × 200 km, collected in the Third National Forest Inventory in 1951–53. Detrended correspondence analysis (DCA) was applied to log-transformed species cover values. It revealed three main gradients: fertility, moisture, and the effect of cattle grazing in forests (still extensive in the early 1950's). The fertility gradient dominated the first axis and the two latter sources of variation confounded with it in a complex manner in the first two axes of DCA. The second DCA axis was associated with canopy effects on understory pattern, with Pinus and Picea having opposite and Betula intermediate effects. These results were compared with an ordination model of Cajander's forest site types, based on DCA of independent, ideal data of 107 indicator species. The fertility gradient recovered by the model was almost identical to that obtained from the field data. The gradient was also stable from intermediate-age (40–69 yrold) to older forests. The forest site types showed rather large overlaps with main neighbouring types in composition of ground vegetation or nutrient status of the humus. Competitively efficient feather-mosses, which are dependent on nutrients released from the tree crowns, are considered important regulators of the understory vegetation. Accordingly, alternative approaches to the forest site type classification to be used in boreal forests treated by modern intensive forestry should give more weight to the effect of the canopy trees.     

Arthropod Diversity in Lama Forest Reserve (South Benin), a Mosaic of Natural, Degraded and Plantation Forests

Arthropod assemblages were examined in Lama forest reserve, a protected area situated in the Dahomey gap, southern Benin, composed of plantations, degraded forest and remnants of natural forest. The objectives were to compare assemblages in relation to forest type and use, to elucidate the value of forest plantations for biodiversity conservation and to identify indicator species for specific forest habitats. Arthropods were collected over an 11-month period, using standardized sets of traps (pitfall, emergence, Malaise and flight intercept traps). Nine different habitats were studied, including natural and degraded forest, forest plantations (Tectona grandis and Senna siamea) of different age, and isolated forest fragments. Our analysis focused on detritivorous and xylophagous arthropods but also included ground beetles and heteropterans, totalling 393 species. We found no differences in species richness among natural and degraded forest habitats in the centre of the reserve (Noyau central). Outside of the Noyau central, species richness was highest in old teak plantations and isolated forest fragments and lowest in young teak and fuelwood plantations. Detrended correspondence analysis (DCA) separated three main groups: (1) natural forest, (2) degraded forest and young plantations, and (3) old plantations and isolated forest fragments. Multiple regression of DCA scores of the first two axes on environmental variables identified one natural and three disturbance-related predictors of arthropod assemblages in Lama forest: soil type (texture), canopy height, naturalness (proportion of Guineo-Congolian plant species) and understorey vegetation cover. We identified 15 indicator species for six different forest habitats. The highest numbers were found in abandoned settlements and old teak plantations. β-diversity was similar among the three DCA ordination groups (degraded forest excluded). Values for β-diversity were relatively high, suggesting that all major forest habitats contribute significantly to regional species pools and should therefore be protected. To enhance arthropod diversity, we propose that management practices in Lama forest should aim to encourage the development of species-rich understorey vegetation of the Guineo-Congolian phytogeographical region.     

Trends in structural compositional attributes of dune-interdune vegetation and their edaphic relations in the Indian desert

Vegetation of 127 sites on different aspects of dune-interdunes in the Indian Thar Desert was classified using TWINSPAN. TWINSPAN groupings of sites separated better vegetated dunes of the northeast form the poorly vegetated dunes of the northwest and the southwest. Of the different ordinations using noncentred, centred and centred and standardized principal component analysis, reciprocal averaging and detrended correspondence analysis (DCA), the site and species classes in DCA correlated well with ten edaphic and ten vegetational attributes of each site. Strong correlation of vegetation groupings with soil texture, moisture holding capacity and low correlation with pH and electrical conductivity revealed the possible importance of soil physical properties in affecting vegetation composition.The 11 species classes in TWINSPAN were regrouped into 18 species classes in DCA, which separated highly frequent species from those of less and least frequent species. Based on dominance-diversity attributes, Calligonum polygonoides-Lasiurus sindicus was brought out as bioedaphic climax stage. Correlation of ordination scores in different site groupings with vegetational attributes showed specific trends: From the zero of x, y and z axes to their maximum, the ordination scores of grasses and browse species declined while score of spinous species increased. The sites near the origin of the x, y and z axes were therefore least degraded and those at or near the maximum of x, y & z axes were most disturbed as was confirmed by the dominance diversity trends. Thus trends of compositional and functional attributes of vegetation of sites in different groupings helped in inferring a site's degradation status.Abbreviations RIV Relative importance value - TWINSPAN Two Way Indicator Species Analysis - PCA Principal Component Analysis - RA Reciprocal Averaging - DCA Detrended Correspondence Analysis - EC Electrical Conductivity - WHC Water Holding Capacity - BD Beta Diversity - DC Dominance Concentration - WWS Windward slope of the dune - LWS Leeward slope of the dune - ID Interdune Nomenclature: Bhandari, (1990)     

Mapping the spatial distribution of plant diversity indices in a tropical forest using multi-spectral satellite image classification and field measurements

The relationships among alpha and beta diversity indices, computed from 141 randomly sampled quadrats, and the vegetation classes obtained by multi-spectral satellite image classification, were used as a strategy for mapping plant diversity in a tropical landscape mosaic. A relatively high accuracy of the land cover map was revealed by the overall accuracy assessment and the Cohen's Kappa statistic. Species accumulation models were used to evaluate how representative the sample size was the different vegetation types. A standard one-way, between-subjects ANOVA confirmed a significant reduction of the within-class variance of plant diversity with respect to their total variance across the landscape. Computed uniformity indices, to assess the internal uniformity of vegetation classes on the diversity indices, confirmed the goodness of the mapped classes in stratifying variability of plant diversity. This allowed for the use of the mapped classes as spatial interpolators of plant diversity values for estimation and up-scaling purposes. Finally, it was revealed that the plant diversity of the landscape depends, to a large extent, on the diversity contained in the most mature forest class, which is also the most diverse community in the studied area. High and moderate beta diversity values between mature forests and both the secondary associations and the first stages of succession, respectively, indicated that there is a significant contribution to the diversity of the landscape by those vegetation classes.     

Landscape mosaic of Araucaria forest and forest monocultures influencing understorey spider assemblages in southern Brazil

Abstract This study investigates how abundance, diversity and composition of understorey spiders were influenced by four different forest habitats in a southern Brazilian Araucaria forest. The study area encompasses a landscape mosaic comprised of Araucaria forest, Araucaria plantation, Pinus plantation, and Eucalyptus plantation. Understorey spiders were collected by beating the vegetation inside three patches of each forest habitat. To assess possible predictors of spider assemblage structure, several patch features were analysed: potential prey abundances, estimation of vegetation cover, diversity index of vegetation types, patch ages, patch areas, and geographical distance between patches. To assess the influence of high‐level taxa approaches on spider assemblage patterns, analyses were carried out individually for family, genera and species levels. Additionally, Mantel tests were carried out in underlying similarity matrices between each taxon. Significant differences in spider abundances among forest habitats were found. Pinus plantations showed the highest abundance of spiders and Eucalyptus plantations showed the lowest abundance. Spider abundance was significantly influenced by patch ages, geographical distance and vegetation cover. Expected numbers of families, genera and species did not vary among forest habitats. Spider composition of two Eucalyptus patches differed from the other forest patches, probably due to their low vegetation cover and isolation. Genera composition was the best correlate of species composition, showing that a higher‐level surrogate can be an alternative to the species approach. The understorey spider diversity in this managed area could be maintained when suitable habitat structures are provided, thus ensuring the connectivity between different habitat types. Further studies should focus on individual species responses to the conversion of native forest to monocultures.     

Stand height and cover type complement forest age structure as a biodiversity indicator in boreal and northern temperate forest management

Forest age structure is one of the main indicators of biodiversity in temperate and boreal forests worldwide. This indicator was mainly chosen for the conservation of a subset of rare or sensitive species related to the oldest age classes, not to capture variability across the entire biodiversity spectrum, but is often considered as such. In this study, we analysed alpha and beta diversity in temporary plots of western Quebec, Canada, to consider biodiversity indicators complementary to existing forest age structure targets. Our analysis revealed that considered individually, stand characteristics such as cover type and height are better predictors of changes in site-level contribution to tree beta diversity than age. We also show that plots belonging to different age classes can be similar in terms of tree alpha diversity. Height class was found to have a more significant impact on tree alpha diversity than expected: height was more important than age in coniferous forests, and in deciduous and mixedwood stands it frequently complemented age in explaining the observed diversity patterns. Our results suggest that forest age structure target levels should not be used as the sole indicator of ecosystem sustainability, and that some mature secondary stands can provide significant contributions to biodiversity. We propose that more efficient trade-offs between forest exploitation, ecosystem functioning and environmental conservation can be attained if: (i) forest age structure targets are complemented by cover type and stand height; or (ii) complementary biodiversity indicators of ecosystem sustainability are implemented.     

林分因子对神木垒不同森林群落林下植物多样性的影响

为探究神木垒不同森林群落林下植物多样性的差异，本研究采用典型样地法，以夹金山神木垒的5种主要森林群落：云杉林、丽江云杉林、红杉林、针阔混交林、阔叶林为研究对象，对不同森林群落林下植物物种组成和物种多样性进行比较，并对林分因子和林下植物多样性进行冗余分析，确定影响林下植物多样性的主要林分因子，为当地森林经营管理提供理论依据。结果表明：（1）在研究区内共记录林下植物147种，隶属于61科，108属；云杉林群落林下植物的科属种组成最丰富。（2）各类型群落的H值、H"值、D值、JSW值均为：草本层＞灌木层；灌木层多样性最高的群落为云杉林群落，草本层多样性最高的群落为丽江云杉林群落，针阔混交林群落、阔叶林群落林下植物多样性较差。（3）平均枝下高与林分密度是影响灌木层物种多样性的主要林分因子（P<0.01），平均枝下高与灌木层的D值、H值、H"值呈负相关关系，林分密度与灌木层4个多样性指数均呈正相关关系；平均枝下高是影响草本层物种多样性的主要林分因子（P<0.01），平均枝下高与草本层H值、H"值、JSW值呈正相关关系。本研究认为，云杉林群落与丽江云杉林群落的林下植物多样性水平较高，平均枝下高与林分密度是影响神木垒不同森林群落林下植物多样性的主要林分因子。     

额尔齐斯河流域垂枝桦林群落结构特征与物种多样性相关分析

为阐明植物群落结构特征和物种多样性之间的相互关系,选择额尔齐斯河流域白桦林国家森林公园的天然垂枝桦(Betula pendula)纯林、垂枝桦苦杨混交林、垂枝桦白柳混交林为研究对象,分林层调查群落的基本特征参数(高度、枝下高、冠幅、胸径、盖度等),计算物种重要值、丰富度指数、多样性指数、均匀度指数,并进行典范对应分析。结果表明:(1)垂枝桦白柳混交林的乔木层树高、枝下高和灌木层的地径、盖度均最高;3种群落的草本层特征参数(除基径)均具有显著差异;垂枝桦白柳林的盖度分别比垂枝桦苦杨林和垂枝桦纯林高19.1%和51.8%。(2)3种群落的乔木层重要值最高为垂枝桦,灌木层为疏花蔷薇(Rosa laxa)、阿尔泰山楂(Crataegus altaica),草本层为莎薹草(Carex bohemica)。(3)3种群落类型中乔木层的丰富度指数R、Simpson指数、Shannon-Wiener指数和灌木层的Pielou指数、Alatalo指数呈现出相同规律,即垂枝桦白柳混交林>垂枝桦苦杨混交林>垂枝桦纯林;草本层中除Alatalo指数之外,其他指数均呈现垂枝桦纯林>垂枝桦苦杨混交林>垂枝桦白柳混交林(P>0.05)。(4)CCA排序结果表明,不同垂枝桦林群落结构特征与物种多样性关系有差异。其中,垂枝桦纯林中,对物种多样性影响最大的是乔木枝下高、灌木株高、冠幅以及草本盖度;垂枝桦苦杨混交林中,对物种多样性影响最大的是乔木高度和冠幅、灌木冠幅和草本高度;垂枝桦白柳林中,对物种多样性影响最大的是乔木胸径、灌木冠幅、盖度以及草本高度。研究表明,乔木枝下高度、灌木冠幅、草本高度是影响3种群落类型物种多样性的主要因素。     

Contrasting effects of mosaic structure on alpha and beta diversity of bird assemblages in a human‐modified landscape

Habitat loss and fragmentation are key processes causing biodiversity loss in human‐modified landscapes. Knowledge of these processes has largely been derived from measuring biodiversity at the scale of ‘within‐habitat’ fragments with the surrounding landscape considered as matrix. Yet, the loss of variation in species assemblages ‘among’ habitat fragments (landscape‐scale) may be as important a driver of biodiversity loss as the loss of diversity ‘within’ habitat fragments (local‐scale). We tested the hypothesis that heterogeneity in vegetation cover is important for maintaining alpha and beta diversity in human‐modified landscapes. We surveyed bird assemblages in eighty 300‐m‐long transects nested within twenty 1‐km² vegetation ‘mosaics’, with mosaics assigned to four categories defined by the cover extent and configuration of native eucalypt forest and exotic pine plantation. We examined bird assemblages at two spatial scales: 1) within and among transects, and 2) within and among mosaics. Alpha diversity was the mean species diversity within‐transects or within‐mosaics and beta diversity quantified the effective number of compositionally distinct transects or mosaics. We found that within‐transect alpha diversity was highest in vegetation mosaics defined by continuous eucalypt forest, lowest in mosaics of continuous pine plantation, and at intermediate levels in mosaics containing eucalypt patches in a pine matrix. We found that eucalypt mosaics had lower beta diversity than other mosaic types when ignoring relative abundances, but had similar or higher beta diversity when weighting with species abundances. Mosaics containing both pine and eucalypt forest differed in their bird compositional variation among transects, despite sharing a similar suite of species. This configuration effect at the mosaic scale reflected differences in vegetation composition among transects. Maintaining heterogeneity in vegetation cover could help to maintain variation among bird assemblages across landscapes, thus partially offsetting local‐scale diversity losses due to fragmentation. Critical to this is the retention of remnant native vegetation.