Trade‐offs between carbon stocks and biodiversity in European temperate forests

Policies to mitigate climate change and biodiversity loss often assume that protecting carbon‐rich forests provides co‐benefits in terms of biodiversity, due to the spatial congruence of carbon stocks and biodiversity at biogeographic scales. However, it remains unclear whether this holds at the scales relevant for management, and particularly large knowledge gaps exist for temperate forests and for taxa other than trees. We built a comprehensive dataset of Central European temperate forest structure and multi‐taxonomic diversity (beetles, birds, bryophytes, fungi, lichens, and plants) across 352 plots. We used Boosted Regression Trees (BRTs) to assess the relationship between above‐ground live carbon stocks and (a) taxon‐specific richness, (b) a unified multidiversity index. We used Threshold Indicator Taxa ANalysis to explore individual species’ responses to changing above‐ground carbon stocks and to detect change‐points in species composition along the carbon‐stock gradient. Our results reveal an overall weak and highly variable relationship between richness and carbon stock at the stand scale, both for individual taxonomic groups and for multidiversity. Similarly, the proportion of win‐win and trade‐off species (i.e., species favored or disadvantaged by increasing carbon stock, respectively) varied substantially across taxa. Win‐win species gradually replaced trade‐off species with increasing carbon, without clear thresholds along the above‐ground carbon gradient, suggesting that community‐level surrogates (e.g., richness) might fail to detect critical changes in biodiversity. Collectively, our analyses highlight that leveraging co‐benefits between carbon and biodiversity in temperate forest may require stand‐scale management that prioritizes either biodiversity or carbon in order to maximize co‐benefits at broader scales. Importantly, this contrasts with tropical forests, where climate and biodiversity objectives can be integrated at the stand scale, thus highlighting the need for context‐specificity when managing for multiple objectives. Accounting for critical change‐points of target taxa can help to deal with this specificity, by defining a safe operating space to manipulate carbon while avoiding biodiversity losses.     

Multi‐taxon and forest structure sampling for identification of indicators and monitoring of old‐growth forest

Abstract

The most commonly used old‐growth forest indicators are structural attributes; nevertheless, they do not necessarily represent the biodiversity value of old‐growth forests. The aim of this study is to analyse the relationships between species richness data of different taxa and structural indicators of old‐growth and to identify taxonomic/functional groups, species and structural attributes that may be used as indicators of old‐growth. To achieve this goal we sampled forest structure, vascular plants, lichens, bryophytes, fungi, saproxylic beetles and birds in mature and old‐growth stands in southern Italy. We calculated Spearman’s correlation coefficients between species richness data and structural attributes. Analyses of indicator species, co‐occurrences and two‐way clusters were performed on the multi‐taxonomic list. The group of vascular plants most significantly correlated with other groups in terms of species richness; furthermore, it displays the highest proportion of between‐group co‐occurrences. The resulting multi‐taxonomic list of potential indicators may serve as an effective means of detecting and monitoring forest ecosystems; however, for this goal, structure‐based indicators, such as forest structural attributes and vascular plant species composition, are of primary importance.     

In search of the best local habitat drivers for saproxylic beetle diversity in temperate deciduous forests

Deadwood-associated species are increasingly targeted in forest biodiversity conservation. In order to improve structural biodiversity indicators and sustainable management guidelines, we need to elucidate ecological and anthropogenic drivers of saproxylic diversity. Herein we aim to disentangle the effects of local habitat attributes which presumably drive saproxylic beetle communities in temperate lowland deciduous forests. We collected data on saproxylic beetles in 104 oak and 49 beech stands in seven French lowland forests and used deadwood, microhabitat and stand features (large trees, openness) as predictor variables to describe local forest conditions. Deadwood diversity and stand openness were consistent key habitat features for species richness and composition in deciduous forests. Large downed deadwood volume was a significant predictor of beetle species richness in oak forests only. In addition, the density of cavity- and fungus-bearing trees had weak but significant effects. We recommend that forest managers favor the local diversification of deadwood types, especially the number of combinations of deadwood positions and tree species, the retention of large downed deadwood and microhabitat-bearing trees in order to maximize the saproxylic beetle diversity at the stand scale in deciduous forests. To improve our understanding of deadwood-biodiversity relationships, further research should be based on targeted surveys on species-microhabitat relationships and should investigate the role of landscape-scale deadwood resources and of historical gaps in continuity of key features availability at the local scale.     

Are Water Beetles Good Indicators of Biodiversity in Mediterranean Aquatic Ecosystems? The Case of the Segura River Basin (SE Spain)

Water beetles were examined for use as potential biodiversity indicators in continental aquatic ecosystems in a semiarid Mediterranean region, the Segura river basin (SE Spain). The indicator value of water beetles was investigated by examining the degree to which their species richness patterns was correlated with other groups (Plecoptera, Trichoptera, Mollusca, Heteroptera and Ephemeroptera), and the efficiency of water beetle area networks (selected by complementarity) in conserving overall groups richness. The species richness patterns of Coleoptera, Ephemeroptera, Plecoptera and Trichoptera were significantly correlated with the Remaining Richness value (RR), defined as the total number of species found at a site (of all six groups examined) minus the number of species belonging to the considered indicator group. Area networks for Coleoptera selected by complementarity represented the highest RR percentage (84.46%) and contained more than 78% species of each group. Furthermore, water beetles meet most of the criteria proposed in the literature for choosing biodiversity indicator taxa. In our study, the correlation values and the percentage of species represented by family, genus and species complementary networks were similar and we suggest that the higher taxa of water beetles (genera or families) can be used as biodiversity surrogates for cost-effective practical surveys.     

Cross-taxon congruence in tree,bird and bat species distributions at a moderate spatial scale across four tropical forest types in the Philippines

Indicator species groups are often used as surrogates for overall biodiversity in conservation planning because inventories of multiple taxa are rare, especially in the tropics where most biodiversity is found. At coarse spatial scales most studies show congruence in the distribution of species richness and of endemic and threatened species of different species groups. At finer spatial scale levels however, cross-taxon congruence patterns are much more ambiguous. In this study we investigated cross-taxon patterns in the distribution of species richness of trees, birds and bats across four tropical forest types in a ca. 100 × 35 km area in the Northern Sierra Madre region of Luzon Island, Philippines. A non-parametric species richness estimator (Chao1) was used to compensate for differential sample sizes, sample strategies and completeness of species richness assessments. We found positive but weak congruence in the distribution of all and endemic tree and bird and tree and bat species richness across the four forest types; strong positive congruence in the distribution of all and endemic bat and bird species richness and low or negative congruence in the distribution of globally threatened species between trees, birds and bats. We also found weak cross-taxon congruence in the complementarity of pairs of forest types in species richness between trees and birds and birds and bats but strong congruence in complementarity of forest pairs between trees and bats. This study provides further evidence that congruence in the distribution of different species groups is often ambiguous at fine to moderate spatial scales. Low or ambiguous cross-taxon congruence complicates the use of indicator species and species groups as a surrogate for biodiversity in general for local systematic conservation planning.     

Indicator groups and congruence of assemblage similarity, species richness and environmental relationships in littoral macroinvertebrates

The rapid decrease of biodiversity and limited resources for surveying it have forced researchers to devise short-cuts for biodiversity surveys and conservation planning. These short-cuts include environmental surrogates, higher taxon surrogates, indicator species and indicator groups. We considered indicator groups as surrogates for wholesale biodiversity and cross-taxon congruence in biodiversity patterns in littoral macroinvertebrates of boreal lakes. Despite the fact that we considered indicator groups amongst a wide variety of taxa, such as two-winged flies, mayflies, caddisflies, beetles, bugs and molluscs, none of the proposed groups possessed all of the qualities of a good indicator taxon for biodiversity surveys and conservation planning. We found generally weak, yet typically significant, relationships between the proposed indicator groups and remaining taxa in both species richness and assemblage similarity. Low congruence was paralleled by somewhat differing relationships of the taxonomic groups to various environmental features of lakes. Furthermore, the relationships of most indicator groups to the environmental features of lakes were not particularly strong. The present findings are unfortunate, because indicator groups did not perform well in predicting the wholesale biodiversity of littoral macroinvertebrates. Thus, there appears to be no short-cut for considering all groups of macroinvertebrates in biodiversity surveys, conservation planning and characterisation of environmental relationships of lake littoral assemblages.     

Biogeographical concordance and efficiency of taxon indicators for establishing conservation priority in a tropical rainforest biota

Prioritizing areas for conservation requires the use of surrogates for assessing overall patterns of biodiversity. Effective surrogates will reflect general biogeographical patterns and the evolutionary processes that have given rise to these and their efficiency is likely to be influenced by several factors, including the spatial scale of species turnover and the overall congruence of the biogeographical history. We examine patterns of surrogacy for insects, snails, one family of plants and vertebrates from rainforests of northeast Queensland, an area characterized by high endemicity and an underlying history of climate-induced vicariance. Nearly all taxa provided some level of prediction of the conservation values for others. However, despite an overall correlation of the patterns of species richness and complementarity, the efficiency of surrogacy was highly asymmetric; snails and insects were strong predictors of conservation priorities for vertebrates, but not vice versa. These results confirm predictions that taxon surrogates can be effective in highly diverse tropical systems where there is a strong history of vicariant biogeography, but also indicate that correlated patterns for species richness and/or complementarity do not guarantee that one taxon will be efficient as a surrogate for another. In our case, the highly diverse and narrowly distributed invertebrates were more efficient as predictors than the less diverse and more broadly distributed vertebrates.     

Co-variation and indicators of species diversity: Can richness of forest-dwelling species be predicted in northern boreal forests?

Design and establishment of ecologically good networks of conservation areas often requires quick assessments of their biodiversity. Reliable indicators would be useful when doing such assessments. In order to explore the potential indicators for species richness in boreal forests, we studied (1) the co-variation of species richness and composition of species assemblages among beetles, polypores, birds and vascular plants, (2) the relationships between species richness and four boreal forest site types, (3) the relationship between species richness and forest physical structure and (4) the suitability of potential indicator groups within the four taxa to predict the species richness generally. The data show that there are probably not a single taxonomic or forest structural characteristic to be used as a general biodiversity indicator or surrogate for all the species. The correlations in species richness among the four taxa studied were low. However, group-specific indicators were obvious: forest site type was a good surrogate for vascular plant richness, and quantity and quality of dead wood predicted the species richness of polypores. The results support the view that different indicators shall be used for different forest types and taxonomic groups. These indicators should facilitate relatively rapid methods to assess biodiversity patterns at the forest stand level.     

Biodiversity surrogate effectiveness in two habitat types of contrasting gradient complexity

Enormous and increasing loss of biodiversity requires evaluation of surrogate taxa as a tool for conservation biology and new reserve selection, in spite of the fact that this approach has become questionable. The aim of this study was to assess the effect of gradient complexity on species richness and community composition among three taxonomic groups. We compared efficiency of vascular plants to indicate diversity of cryptogams (bryophytes, lichens) and snails in two contrasting habitat types (treeless fens and forests) within the same geographic region. We examined correlation of their species richness (Spearman rank correlation), community composition (Bray–Curtis similarity, Mantel test) and their responses to environmental variables (detrended and canonical correspondence analysis). We also focused on Red List species. We found that spatial congruence among studied taxa was affected by habitat type, however vascular plants were good indicator of snail biodiversity in both habitats. Nevertheless, all significant positive correlations of species richness were associated with the congruence in main environmental gradients. Although there was a consistency in significantly positive cross-taxon correlation in community similarity, the congruence was insufficient for conservation purposes. Furthermore we confirmed the necessity of integration of at-risk species in conservation planning as Red List species were poor indicators for total species richness and vice versa. We suggest the complementation of existing reserve network with small-scale protected areas focused on conservation of at-risk ecosystems, communities or species. In this study vascular plants were not found as a sufficient indicator for fine-filter conservation of other taxa.     

Saproxylic beetle assemblages related to silvicultural management intensity and stand structures in a beech forest in Southern Germany

Compared to agricultural land and spruce plantations, central European beech-oak forests are often relatively close to natural conditions. However, forest management may alter these conditions. In Steigerwald, southern Germany, a large beech-dominated forest area, three management intensities were applied during the past 30–70 years. Here, we examined the influence of management intensity on saproxylic beetles in >100-year old mature stands at 69 sampling plots in 2004. We sampled beetles using flight-window traps and time standard direct searches. The community structure based on presence/absence data changed remarkably along the gradient from unmanaged to low-intensity to high-intensity management, but these differences were not evident using abundance data from flight interception traps. Saproxylic species richness decreased in intensively managed forests. Elateridae and threatened species richness peaked in unmanaged forests and in forests under low-intensity management. Saproxylic species richness was dependent on certain micro-habitat factors. These factors were (1) the amount of dead wood for Elateridae, overall and threatened saproxylic beetle richness; (2) the amount of flowering plants for Cerambycidae; (3) the richness of wood-inhabiting fungi for Staphylinidae, Melandryidae and overall saproxylic beetle richness; and (4) the frequency of Fomes fomentarius for threatened species. Species richness was better explained by plot factors, such as dead wood or fungi, than by management intensity. These results suggest that the natural variation of dead wood niches (decay stages, snag sizes, tree cavities and wood-inhabiting fungi species) must be maintained to efficiently conserve the whole saproxylic beetle fauna of beech forests. Also, intensive management may alter the specialised saproxylic beetle community even if the initial tree-species composition is maintained, which was the case in our study. For monitoring the ecological sustainability of forest management we must focus on threatened species. If structures alone are sampled then the amount of dead wood is the best indicator for a rich saproxylic beetle fauna.     

Deadwood as a surrogate for forest biodiversity: Meta-analysis of correlations between deadwood volume and species richness of saproxylic organisms

Deadwood is an important component of forest ecosystems on which many forest dwelling species depend. Deadwood volume is therefore widely used as an indicator of forest biodiversity, notably throughout Europe. However, using deadwood as an indicator has mostly been based on boreal references, and published references for temperate forests are scarce. As a result, the magnitude of the relationship between deadwood volume and species richness remains unclear for saproxylic species. We used meta-analysis to study the correlation between deadwood volume and the species richness of saproxylic beetles and fungi relative to several predictors at the forest stand level: biome, type of deadwood (log, snag, and stump) and decay class (fresh vs. decayed). We showed that the correlation between deadwood volume and species richness of saproxylic organisms was significant but moderate (r = 0.31), and that it varied only slightly between logs and snags or between decay stages. However, we found a strong biome effect: deadwood volume and species richness were more correlated in boreal forests than in temperate forests. This could be attributed both to differences in the history of forest management between biomes and to varying landscape patterns. Finally, we conclude that total deadwood volume is probably not a sufficient indicator of saproxylic biodiversity, and those additional variables (notably at the landscape level) such as type of deadwood or decay class should be integrated in deadwood monitoring. In addition, further forest research is needed to better assess the quantitative relationship between deadwood and saproxylic biodiversity, and in order to build indicators adapted to different biome contexts.     

Spatial and temporal scales relevant for conservation of dead-wood associated species: current status and perspectives

Dead wood is a key substrate for forest biodiversity, hosting a rich and often threatened biodiversity of wood-living species. However, the relationship between the occurrence of dead wood and associated species is modified by several environmental factors. Here we review the present state of knowledge on how dead wood on different spatial and temporal scales affects saproxylic biodiversity. We searched for peer-reviewed studies on saproxylic species that compared dead wood distribution on at least two spatial or temporal scales. We scanned close to 300 articles, of which 34 fit our criteria. 20 studies were directed towards the current amount of dead wood at different scale levels and how this relates to the abundance or occurrence of saproxylic species, embracing scales from 10 m to 10 km. 14 studies compared time-lagged effects of dead wood, covering time-lags from 25 years to more than 200 years. The reviewed articles focused mainly on European forest and addressed invertebrates (mostly beetles), alone or in combination with fungi (27 articles), fungi (six articles), or lichens (one article). Although the significance of dead wood for forest biodiversity is firmly established, the reviewed studies show that we still have limited knowledge of the relationship between saproxylic biodiversity and spatial and temporal scales. Based on the reviewed studies, we conclude that there is large variation in response to spatial and temporal dead wood patterns between different taxa and sub-groups. Still, several of the reviewed papers indicate that time-lagged effects deserve more attention, especially on a landscape scale and for specialized or red-listed species. Further work is required before firm management recommendations can be suggested.     

Species richness of saproxylic beetles in woodlands is affected by dispersion ability of species,age and stand size

This study examines the occurrence of saproxylic beetles in woodlands of different size and age and their potential to leave woodland areas and cross open grassland in northern Germany. The beetles were recorded by emergence traps and flight-intercept-traps. The investigated sites were dominated by beech, oak and alder, but other tree species also occurred in low abundance. Species richness showed a positive relation to stand size and age of woods. Both total and rarefaction species richness were the lowest in small and young woods and highest in old and large woods. Species richness decreased asymptotically from the inner-wood habitat to a distance greater than 80 m from the wood margin. 80 species were classified into 46 low mobile species found at a distance <30 m from wood margins and 34 high mobile species found >30 m from wood margins. The most mobile species were found the most frequently in all woods; but they contributed less to species richness in wood stands than did the species with low mobility. The contribution of the least mobile species to species richness in wood stands increased with the age and size of the stands, with the effect of stand size being the greater. We conclude that in our study region woods larger than 100 ha are necessary to maintain the highest richness of the least mobile saproxylic beetles.     

Vascular plants as surrogates of butterfly and grasshopper diversity on two Swiss subalpine summer pastures

Summer pastures in the Swiss Alps are currently affected by land-use changes that cause a decrease in biodiversity. Although these habitats make up one-third of the whole Swiss agricultural area, direct payments dedicated to support their management are very low. Current political instruments do not support efforts to conserve the biodiversity in these areas, but a vegetation-based approach such as the one implemented in the permanently utilized agricultural areas is under discussion. However, available studies evaluating the surrogate value of vascular plants for other (particularly animal) taxa have yielded inconsistent results, and very few have been conducted in habitats at high elevations. We investigated the extent to which vascular plants are adequate surrogates for butterfly and grasshopper diversity, examining the congruence of species richness and community similarity in two heterogeneous subalpine pastures in the Swiss Alps. Results at the species richness level (Spearman’s rank correlation) varied widely according to the study site and taxa assessed. In contrast, at the community similarity level (Procrustean randomization tests with Bray–Curtis similarity), congruencies between vascular plant and invertebrate taxa were generally highly significant. We therefore recommend the use of community similarity as a basis for estimating biodiversity patterns. Our results suggest that conservation measures aimed primarily at enhancing the floristic diversity of subalpine grasslands are also likely to benefit butterfly and grasshopper diversity, at least at the local scale.     

Long‐term development of species richness in a central European beech (Fagus sylvatica) forest affected by windthrow—Support for the intermediate disturbance hypothesis?

On the basis of long‐term surveys of permanent plots and traps, we examined the communities of saproxylic beetles, fungi, herbs, and trees on an untreated 22 ha large beech forest windthrow and asked whether the results lend support to the intermediate disturbance hypothesis (IDH). We studied species richness and the similarity of community composition. Additionally, we grouped species by their frequency trend over time to successional model types to examine whether, corresponding to the IDH, the diversity of these groups explained peak richness at intermediate intervals after the disturbance. In line with the IDH, species richness showed a hump‐backed temporal course for alpha and gamma diversity. We found evidence for a linear succession directly after the disturbance. This, however, did not continue, and in all species groups, a partial recovery of the initial community was observed. In the case of fungi, herbs, and trees, but not for saproxylic beetles, alpha diversity was driven by the diversity of the successional model types. Our results underline that the mechanisms driving species richness after disturbances are more complex than the IDH suggests and that these mechanisms vary with species group. We assumed that, besides competition, legacy effects, facilitation, habitat heterogeneity, and random saturation of the species pool are important. In case of trees and herbs, we found indications for strong legacy and competition effects. For fungi and beetles, substrate heterogeneity and microclimate were assumed to be important. We concluded that disturbances contribute to increasing species richness not only by reducing the effectiveness of competitors but also by increasing the amount and diversity of resources, as well as their rate of change over time.     

Oak woodland restoration: testing the effects on biodiversity of mycetophilids in southern Sweden

The effect of harvesting biofuel and woodland restoration on biodiversity is debated. To evaluate the effects of partial cutting on more organism groups, we used pairwise experimental and undisturbed control stands in a large landscape. On average 26% of the basal area including 50–95% of the understorey was harvested at each of 15 oak-rich forest sites. Our earlier results of partial cutting suggested a positive short-term effect for vascular plants and beetles and no or minor negative effects for fungi. Here we analyse the response of mycetophilids (Diptera: Sciaroidea excl. Sciaridae), a neglected but species-rich insect group that was strongly disfavoured by clear-cutting in previous studies. Increased deadwood (slash) caused increase in the number of individuals of mycetophilids associated with wood or wood fungi. The rarefaction species numbers of mycetophilids declined after the treatment, but the absolute number of species was not affected. Our results indicate that a 25% harvest can be compatible with conservation of vascular plants, fungi, saproxylic and herbivorous beetles and mycetophilids in temperate hardwood stands of the type studied. However, more studies are needed to determine what level(s) of stand thinning can be tolerated by different taxa in landscapes with small fragmented conservation stands.     

Saproxylic insects and fungi in deciduous forests along a rural–urban gradient

Urbanization is increasing worldwide and is regarded a major threat to biodiversity in forests. As consequences of intensive human use, the vegetation structure of naturally growing urban forests and their amount of deadwood can be reduced. Deadwood is an essential resource for various saproxylic insects and fungi. We assessed the effects of urbanization and forest characteristics on saproxylic insects and fungi. We exposed standardized bundles consisting of each three freshly cut beech and oak branches in 25 forests along a rural–urban gradient in Basel (Switzerland). After an exposure of 8 months, we extracted the saproxylic insects for 10 months using an emergence trap for each bundle. We used drilling chips from each branch to determine fungal operational taxonomic units (OTUs). In all, 193,534 insect individuals emerged from the experimental bundles. Our study showed that the abundance of total saproxylic insects, bark beetles, longhorn beetles, total flies, moths, and ichneumonid wasps decreased with increasing degree of urbanization, but not their species richness. However, the taxonomic composition of all insect groups combined was altered by wood moisture of branches and that of saproxylic beetles was influenced by the degree of urbanization. Unexpectedly, forest size and local forest characteristics had a minor effect on saproxylic insects. ITS (internal transcribed spacer of rDNA) analysis with fungal specific primers revealed a total of 97 fungal OTUs on the bundles. The number of total fungal OTUs decreased with increasing degree of urbanization and was affected by the volume of naturally occurring fine woody debris. The composition of fungal OTUs was altered by the degree of urbanization and pH of the branch wood. As a consequence of the altered compositions of saproxylics, the association between total saproxylic insects and fungi changed along the rural–urban gradient. Our study shows that urbanization can negatively impact saproxylic insects and fungi.     

Operationalizing biodiversity for conservation planning

Biodiversity has acquired such a general meaning that people now find it difficult to pin down a precise sense for planning and policy-making aimed at biodiversity conservation. Because biodiversity is rooted in place, the task of conserving biodiversity should target places for conservation action; and because all places contain biodiversity, but not all places can be targeted for action, places have to be prioritized. What is needed for this is a measure of the extent to which biodiversity varies from place to place. We do not need a precise measure of biodiversity to prioritize places. Relative estimates of similarity or difference can be derived using partial measures, or what have come to be called biodiversity surrogates. Biodiversity surrogates are supposed to stand in for general biodiversity in planning applications. We distinguish between true surrogates, those that might truly stand in for general biodiversity, and estimator surrogates, which have true surrogates as their target variable. For example, species richness has traditionally been the estimator surrogate for the true surrogate, species diversity. But species richness does not capture the differences in composition between places; the essence of biodiversity. Another measure, called complementarity, explicitly captures the differences between places as we iterate the process of place prioritization, starting with an initial place. The relative concept of biodiversity built into the definition of complementarity has the level of precision needed to undertake conservation planning.     

Can higher taxa be used as a surrogate for species-level data in biodiversity surveys of litter/soil insects?

We investigate the usefulness of higher taxa as surrogates for species richness and diversity of litter/soil insects. We use data for Coleoptera (beetles) and Formicidae (ants) collected during biodiversity surveys of five tropical and two temperate countries, and use Pearson’s product moment correlations to assess the surrogacy relationship. Our results suggest that genera would provide an adequate surrogate for species richness of Coleoptera, but not for Formicidae. We suggest that the usefulness of higher taxa as surrogates for richness is dependent on both taxonomy and scale. Higher taxa provided a poor surrogate for species diversity due to the added dimension of evenness of community structure, and we recommend that higher taxa should not be used as surrogates for species diversity.     

Birds as surrogates for mammals and reptiles: Are patterns of cross-taxonomic associations stable over time in a human-modified landscape?

Cross-taxonomic surrogates can be feasible alternatives to direct measurements of biodiversity in conservation if validated with robust data and used with explicit goals. However, few studies of cross-taxonomic surrogates have examined how temporal changes in composition or richness in one taxon can drive variation in concordant patterns of diversity in another taxon, particularly in a dynamic and heavily modified landscape. We examined this problem by assessing changes in cross-taxonomic associations over time between the surrogate (birds) and target vertebrate taxa (mammals, reptiles) that demand high sampling effort, in a heterogeneous mosaic landscape comprising pine monoculture, eucalypt woodland remnants and agricultural land. Focussing on four study years (1999, 2001, 2011, 2013) from a dataset spanning 15 years, we: (1) investigated temporal changes in cross-taxonomic congruency among three animal taxa, (2) explored how temporal variation in composition and species richness of each taxon might account for variation in cross-taxonomic congruency, and (3) identified habitat structural variables that are strongly correlated with species composition of each taxon. We found the strength of cross-taxonomic congruency varied between taxa in response to both landscape context and over time. Among the three taxa, overall correlations were weak but were consistently positive and strongest between birds and mammals, while correlations involving reptiles were usually weak and negative. We also found that stronger species richness and composition correlations between birds and mammals were not only more prevalent in woodland remnants in the agricultural matrix, but they also increased in strength over time. Temporal shifts in species composition differed in rate and extent among the taxa even though these changes were significant over time, while important habitat structural correlates were seldom shared across taxa. Our study highlights the role of the landscape matrix and time in shaping animal communities and the resulting cross-taxonomic associations in the woodland remnants, especially after a major perturbation event (i.e. plantation establishment). In such dynamic landscapes, differing and taxon-specific shifts in diversity over time can influence the strength, direction and consistency of cross-taxonomic correlations, therefore posing a ‘temporal’ problem for the use of surrogates like birds in monitoring and assessments of biodiversity, and conservation management practices.