Does colonization contribute to spatial patterns of common invertebrates in coralline algal turf?

Abstract The potential of colonization to contribute to the spatial patterns of six common invertebrates in coralline algal turf was investigated on a rocky shore near Sydney, Australia. The species, which included two amphipods (Elasmopus warra, Hyale spp.), a small bivalve (Lasaea australis), a fly larva (Limonia marina), and two microgastropods (Amphithalamus incidata and Eatoniella atropurpurea), had a range of dispersal modes (larval dispersal, crawling, swimming, rafting, and passive transport). Field sampling between May 1997 and November 1999 demonstrated that the amphipods were more abundant in low‐shore areas, the fly larvae and bivalves were more abundant in mid‐shore areas, and the abundances of gastropods did not vary with tidal height. Furthermore, abundances of all species varied among patches separated by tens of metres at one time or another. To test whether rates of colonization could contribute to established patterns of abundance, habitat mimics were deployed for 2‐week periods. The supply of new individuals matched long‐term patterns of abundance at different tidal heights for E. warra and L. marina. Colonization rates also differed among patches separated by tens of metres for three of the six species. Overall, there was little evidence to suggest that common species in coralline turf are limited by colonization on local scales, regardless of their major mode of dispersal. However, the potential for colonization to determine patterns of abundance varied from species to species.     

Intertidal assemblages associated with natural<Emphasis Type="Italic">corallina</Emphasis> turf and invasive mussel beds

There is considerable concern about conservation of biodiversity in highly disturbed and urbanized environments, although a very large proportion of biodiversity (i.e. the small and cryptic invertebrates) have been little studied in this regard. Many biogenic structures (e.g. coral reefs, mussel beds, foliose algae) provide habitat for a large number of small invertebrates. The features of these habitats to which these animals respond are complex and poorly documented. Invasive species are increasing in abundance and diversity in many disturbed estuaries, but most previous studies have concentrated on effects of invasive species on surrounding macroscopic assemblages. This study examines the assemblages of small invertebrates and algae living in natural patches of coralline turf and in patches of the invasive mussel, Mytilus galloprovincialis, on seawalls in Sydney Harbour. Although most taxa identified were common to both habitats, they were generally more abundant in turf than in the mussels, especially the more widespread and numerous taxa. Few taxa were unique to either habitat and those were generally sparse and patchy. In addition, there were relatively more smaller animals in the algal turf than in the mussels, although it is not known whether these were juveniles of adults present in both habitats, or different species. These data show that coralline turf and mussel beds do not provide similar intertidal habitat for associated assemblages and that overgrowth of natural biota by mussels may have strong indirect effects on associated assemblages. These warrant further experimental investigation, so that the effects of invasive species on local biodiversity can be better understood and managed.     

Inconsistency in short-term temporal variability of microgastropods within and between two different intertidal habitats

Small-scale temporal variation in abundances of fauna in marine soft sediments has long been recognised. Many studies on rocky intertidal shores have, however, focused on larger fauna in single habitats and have primarily examined relatively long time-scales. The implications of small-scale variability are frequently not adequately addressed in the studies of changes in fauna over longer time-scales. Without knowledge of the magnitude of variation at smaller scales, comparisons across longer time-scales may be confounded. In this study, the temporal variability of a number of co-existing species of microgastropods in patches of two different intertidal habitats (coralline turf and sediment) in Botany Bay, New South Wales, Australia, was measured using a nested, hierarchical sampling design incorporating temporal scales of weeks, 1 and 3 months. In addition to habitats, there were also spatial scales of metres between plots and 100s of metres between the locations. There was generally a lack of consistency in the trends of variance for the three temporal scales at the smallest spatial scale of plots. In addition, the different species, including those that were closely related, showed different patterns of variation, depending on the habitat and site. These data show the importance of incorporating adequate scales of sampling in different habitats when analysing the distribution and abundance of microbenthos in intertidal habitats.     

Colonization of subtidal macroalgae in a fucalean-dominated algal assemblage,southwestern Australia

The influence of fucalean canopy species and dominant understory macroalgae on algal colonization was investigated to evaluate whether layering contributes to patterns in algal diversity. Patterns in recruitment were compared among total-clearing, understory-removal, canopy-removal, and undisturbed plots (plot area = 0.25 m²), using a randomized block design in depths <10 m and 10–20 m at Woody Island, Western Australia. To evaluate if propagules were available in the water column above the canopy layer, settlement plates (plate area = 0.04 m²) were deployed in depths <10 m, 10–20 m, and >20 m. A total of 198 macroalgal species was recorded. Biomass of the understory species Osmundaria prolifera Lamouroux and Botryocladia sonderi Silva was similar between canopy-removal and undisturbed plots. Diversity of macroalgae was similar in the presence and absence of a canopy layer. Taxa found in the canopy showed different patterns in recruitment. Cystoseiraceae recruited predominantly in total-clearings in both depth strata. Sargassaceae recruited most abundantly in depths <10 m. Density of canopy taxa on settlement plates was similar with depth (20–30 juveniles per plate), and juveniles were mainly Cystoseiraceae. In contrast to kelp beds or forests, patterns in algal colonization appeared to be maintained by environmental factors or processes other than the direct effects of layering in the subtidal fucoid-dominated assemblages at Woody Island. Handling editor: K. Martens     

Early colonization of shallow subtidal boulders in two habitats

Intertidal and shallow subtidal boulder fields are relatively uncommon along the coast of New South Wales, Australia. Nevertheless, they provide habitat for a diverse suite of species, many of which are seldom found in other habitats. The types and abundances of animals found on or under boulders can be influenced by features of the boulders themselves, or by features of the substratum on which a boulder lies. Boulders can be colonized by larvae, or by adult or juvenile animals drifting in the water column or crawling up from the substratum. This experiment investigated the effect of an algal or sandy substratum on early stages of colonization of new boulders in two boulder fields by a suite of invertebrates, including gastropods, bivalves, chitons, polychaetes and insect larvae. Replicate times of three different periods (5, 18 and 38 days) tested for consistency of patterns of colonization at different times. Although the experiment was completed in a single season (within 2 months), there was considerable variation in patterns of abundances and diversity between replicate times. Thus, for each time in each period of a particular length, a different assemblage developed on the algal or sandy substratum in each boulder field. Despite this temporal variation, a few taxa showed some consistency of colonization among habitats, although most showed unpredictable patterns. The implications of these patterns of colonization for the creation or restoration of new intertidal and shallow subtidal boulder fields are discussed.     

Processes regulating early post-settlement habitat use in a subtidal assemblage of brachyuran decapods

In highly mobile animals post-settlement dispersion of juveniles can strongly influence the observed patterns of abundance and distribution. To explore the relative importance of factors regulating the use of habitat by crabs we performed a multi-species manipulative experiment in a subtidal environment of the central Chilean coast. First, demographic patterns were established by performing a year-round crab survey in three discrete and well-known subtidal crab habitats: (1) algal turf, (2) cobbles and (3) shell hash. Second, habitat preferences were experimentally evaluated using concrete trays that were filled with different substrate types that simulate natural habitats. Settlement and recruitment rates were estimated from experimental trays that were left in the field and surveyed after 2 weeks (complete experiment was repeated 7 times throughout 1 year). Third, mortality, due to predation, was assessed by covering 50% of the trays with a 4-mm mesh-size screen that excluded large predators (i.e., fishes, shrimps). Fourth, habitat colonization rates were evaluated by quantifying the arrival, into open trays, of large juveniles (secondary dispersal). The most abundant species in this system (Paraxhantus barbiger, Cancer setosus, Taliepus dentatus and Pilumnoides perlatus) displayed clear habitat preferences at the time of settlement, evidenced by differences in density of recruits among habitats. Recruitment regulation by predation seemed to explain the observed patterns in only one case. For most species, however, evidence of ontogenetic change in the use of habitat, through active habitat redistribution by large juveniles, was detected. Thus, secondary dispersal among habitats seems to outweigh the influence of megalopae's habitat selection and post-settlement mortality as responsible for the observed demographic patterns.     

Macroalgal Composition Determines the Structure of Benthic Assemblages Colonizing Fragmented Habitats

Understanding the consequences of fragmentation of coastal habitats is an important topic of discussion in marine ecology. Research on the effects of fragmentation has revealed complex and context-dependent biotic responses, which prevent generalizations across different habitats or study organisms. The effects of fragmentation in marine environments have been rarely investigated across heterogeneous habitats, since most studies have focused on a single type of habitat or patch. In this study, we assessed the effects of different levels of fragmentation (i.e. decreasing size of patches without overall habitat loss). We measured these effects using assemblages of macro-invertebrates colonizing representative morphological groups of intertidal macroalgae (e.g. encrusting, turf and canopy-forming algae). For this purpose, we constructed artificial assemblages with different combinations of morphological groups and increasing levels of fragmentation by manipulating the amount of bare rock or the spatial arrangement of different species in mixed assemblages. In general, our results showed that 1) fragmentation did not significantly affect the assemblages of macroinvertebrates; 2) at greater levels of fragmentation, there were greater numbers of species in mixed algal assemblages, suggesting that higher habitat complexity promotes species colonization. Our results suggest that predicting the consequences of fragmentation in heterogeneous habitats is dependent on the type and diversity of morphological groups making up those habitats.     

Mechanisms of recovery and resilience of different components of mosaics of habitats on shallow rocky reefs

Understanding the mechanisms producing and maintaining discontinuities between patches in mosaics of habitats is necessary to predict changes in patterns of abundance and distribution of species. On temperate rocky reefs, physical and biological disturbance can result in a mosaic of patches of encrusting coralline, turf- or canopy-forming algae. We experimentally investigated the effects of disturbance within and at the boundary between these patches, in order to identify mechanisms accounting for re-colonisation of space and to assess whether the response of boundaries can alter the relative size of contrasting habitats. Also, we tested whether the resilience of the different types of assemblages depends on species richness (i.e. number of taxa present) of habitats or, alternatively, on other properties of systems like differences in life-history traits of dominating species. Although the nature of the mechanisms generating differences among habitats changed among different stages of the colonisation, local processes (within patches) prevailed over larger scale processes (among patches) in determining early patterns of colonisation of space in mosaics. By the end of the experiment, assemblages in clearings at boundaries had recovered to the undisturbed reference condition, in contrast to clearings within barren patches or algal turfs. Boundaries represent, therefore, relatively more stable components of the mosaic, with greater resilience than adjacent habitats. Although sea urchins are often indicated as the main force regulating the proportion of contrasting habitats on shallow rocky reefs, determining the nature of variation in the interaction between species dominating each type of habitat is crucial to understand dynamics of mosaics. Finally, our study provides evidence that resilience could not be entirely controlled by initial species diversity, suggesting that different proportions of dominant taxa could influence the stability of natural systems.     

Importance of patch scale vs landscape scale on selected forest birds

The management and protection of natural areas have primarily occurred in isolation from surrounding land management. The structure of surrounding land cover, however, may be important to the abundance and reproductive success of birds within a habitat patch. We investigated the relative importance of forest patch area, within patch habitat and surrounding landscape forest cover on the abundance of three Neotropical migrant bird species thought to be area-sensitive (ovenbird [ Seiurus aurocapillus ], wood thrush [ Hylocichla mustelina ] and red-eyed vireo [ Vireo olivaceus ]), and on pairing success of the ovenbird. We selected 31 isolated forest patches of differing sizes, and three 80-ha plots in continuous forest each centered within non-overlapping 200-ha landscapes, such that patch area and landscape forest cover were uncorrelated among landscapes. Each study plot was surveyed to estimate abundances of territorial males and ovenbird pairing success. Landscape forest cover ( p <0.05) explained the most variation in ovenbird abundance, while percent deciduous forest cover within patches ( p <0.05) and patch size ( p <0.05) explained the most variation in red-eyed vireo and wood thrush abundance, respectively. Patch size was a significant ( p <0.05) predictor of abundance for all three study species; however, density for all species decreased significantly ( p <0.05) with patch size. Ovenbird pairing success was higher in continuous forest plots than in forest patches ( p =0.018). This study's findings suggest that the relative importance of within patch characteristics, patch size and landscape forest cover varies for different bird species, and that conservation efforts would benefit from the inclusion of all three factors.     

重庆中梁山不同石漠化生境中石生南亚毛灰藓斑块的空间分布格局

基于重庆市中梁山喀斯特(Karst)地区3种不同石漠化生境(潜在石漠化、轻度石漠化和中度石漠化)中0.75 hm2样地的数据,以石生南亚毛灰藓(Homomallium simlaense)的3种斑块(小斑块、中斑块和大斑块)为研究对象,运用点格局O-ring的单变量和双变量统计方法对斑块空间格局以及斑块间的关联性进行生态学特性与形成过程分析,取得以下结果。(1)南亚毛灰藓总斑块数量关系为轻度石漠化潜在石漠化中度石漠化;在3种石漠化生境中,各种类型的斑块均呈现出小斑块中斑块大斑块的数量变化。(2)小斑块和中斑块在小尺度上主要为聚集分布,其它尺度上为随机分布;大斑块在整个尺度上都呈随机分布。(3)中斑块与小斑块在3种生境中均在小尺度上有显著的关联性;大斑块与中斑块仅在潜在石漠化生境中的小尺度上有关联性,其它斑块间在不同生境与尺度上均无关联性。(4)环境因子中坡度和石缝数对斑块的分布起很大作用,但是相对湿度是影响分布的主要因子。(5)在相对湿度和郁闭度胁迫方面,小斑块和中斑块随环境胁迫增大而趋于聚集分布。研究结果表明,苔藓斑块大小及其分布式样在石漠化地区裸露岩石的生态恢复中具有重要指示意义。     

Patch size drives colonization by aquatic insects,with minor priority effects of a cohabitant

Patch size is one of the most important factors affecting the distribution and abundance of species, and recent research has shown that patch size is an important niche dimension affecting community structure in aquatic insects. Building on this result, we examined the impact of patch size in conjunction with presence of larval anurans on colonization by aquatic insects. Hyla chrysoscelis (Cope''s gray treefrog) larvae are abundant and early colonists in fishless lentic habitats, and these larvae can fill multiple ecological roles. By establishing larvae in mesocosms prior to colonization, we were able to assess whether H. chrysoscelis larvae have priority effects on aquatic insect assemblages. We conducted a series of three experiments in naturally colonized experimental landscapes to test whether (1) H. chrysoscelis larval density affects insect colonization, (2) variation in patch size affects insect colonization, and (3) the presence and larval density of H. chrysoscelis shift colonization of insects between patches of different size. Larval density independently had almost no effect on colonization, while patch size had species‐specific effects consistent with prior work. When larvae and patch size were tested in conjunction, patch size had numerous, often strong, species‐specific effects on colonization; larval density had effects largely limited to the assemblages of colonizing beetles and water bugs, with few effects on individual species. Higher larval densities in large mesocosms shifted some insect colonization to smaller patches, resulting in higher beta diversity among small patches in proximity to high density large mesocosms. This indicates establishing H. chrysoscelis larvae prior to insect colonization can likely create priority effects that slightly shape insect communities. Our results support the importance of patch size in studying species abundances and distributions and also indicate that colonization order plays an important role in determining the communities found within habitat patches.     

A comparison of the responses of two tropical specialist herbivores to host plant patch size

Summary The effects of host plant patch size on the abundances of two specialist herbivores (the chrysomelid beetle, Acalymma innubum and the pentatomid bug, Piezosternum subulatum) were investigated in a natural forest community in the Virgin Islands. Abundances were compared early and late in the season in different sized patches of the cucurbit host plant (Cayaponia americana) growing in open habitat (with no surrounding plant community) and forest habitat (with diverse surrounding plant community). For both herbivore species, adult abundances per patch were positively correlated with patch leaf area, but there was a significant patch size effect (i.e., correlation between herbivore density per unit plant and patch leaf area) only for beetles in the forest habitat. Both herbivore species were significantly affected by surrounding plant diversity, but in opposite ways: beetles were more abundant in open patches whereas bugs were more abundant in forest patches. Relationships between abundance and patch size in open and forest patches changed through the season for both herbivore species. These changing abundance patterns are discussed with respect to (1) increases in the diversity of the plant community surrounding host plant patches, and (2) differences in herbivore movement patterns.     

Extinction-colonization dynamics and host-plant choice in butterfly metapopulations

Species living in highly fragmented landscapes often occur as metapopulations with frequent population turnover. Turnover rate is known to depend on ecological factors, such as population size and connectivity, but it may also be influenced by the phenotypic and genotypic composition of populations. The Glanville fritillary butterfly (Melitaea cinxia) in Finland uses two host-plant species that vary in their relative abundances among distinct habitat patches (dry meadows) in a large network of approximately 1,700 patches. We found no effect of host species use on local extinction. In contrast, population establishment was strongly influenced by the match between the host species composition of an empty habitat patch and the relative host use by larvae in previous years in the habitat patches that were well connected to the target patch. This "colonization effect" could be due to spatially variable plant acceptability or resistance or to spatially variable insect oviposition preference or larval performance. We show that spatial variation in adult oviposition preference occurs at the relevant spatial scale and that the other possible causes of the colonization effect can be discounted. We conclude that the colonization effect is generated by host preference influencing the movement patterns of ovipositing females. Migrant females with dissimilar host preferences have different perceptions of relative patch quality, which influences their likelihood of colonizing patches with particular host composition.     

Experimental analyses of patch selection by foraging black surfperch (Embiotoca jacksoni Agazzi)

The dynamics of microhabitat use by foraging adult and juvenile black surfperch (Embiotocajacksoni Agazzi) were explored. Detailed observations of black surfperch feeding at Santa Catalina Island, California, revealed that adults and young-of-year juveniles co-occurred in the same habitat but used different algal substrata as foraging sites. Juveniles selected invertebrate prey almost exclusively from the surface of foliose algae. The occurrence of young E. jacksoni was highly correlated with that of foliose algae. Adults tended to bite most frequently from turf, a low-growing matrix of plants, colonial animals, and debris covering the rocky substratum. The abundance of adults was negatively correlated with the occurrence of foliose algae. Adults and juveniles showed marked, but different, preferences in their utilization of taxa of algae as foraging substrata. Certain algae (e.g., Zonaria farlowii Setchell & Gardner) were preferred while other taxa (e.g., Sargassum palmeri Grun) were avoided by both age groups. However, most types of algae were preferred by one group but not the other. To test the hypothesis that knowledge of algal substratum composition allows prediction of fish occurrence and foraging behavior in a patch, algal cover on 2 × 2 m² areas of bottom was manipulated creating plots dominated by turf, Zonaria farlowii, or Sargassum palmeri. Fish occurrence could be accurately predicted on the basis of abundance of foliose algae, but foraging activity of fish was highly dependent on the algal taxon that dominated the patch. Differential prey availabilities among foraging substrata provided some insight into the patterns of foraging patch preferences displayed by adult and juvenile Embiotoca jacksoni.     

Algae-associated marine molluscs in the Azores

The raolluscan fauna of a special habitat, the high intertidal algal turf, was studied at four stations on the island of Sao Miguel, Azores. The number of species found ranged from 13 to 23. However, a small group of only six species (the bivalve Lasaea adansoni and the gastropods Pisinna punctulum, Omalogyra atomus, Fossarus ambiguus, Skeneopsis planorbis and Alvania postrema) accounted for more than 80% of all the specimens collected. Mollusc density reached values of 20000 specimens per 100 g algal dry weight. The abundance and number of species of molluscs was comparable with those reported for algal zones lower on the Azorean shores.
Wave exposure and seasonality effects were found to be small, presumably because of the relatively mild abiotic conditions and the protective role of the turf. The algal substrata influenced the phytal molluscan community in two ways. First, the abundance of molluscs was significantly correlated with algal dry weight. Secondly, molluscan abundance and diversity were influenced by the algal composition of the turf. A rich algal composition, with several species of branched fleshy and coralline algae, was associated with a rich molluscan fauna. The dominance of coralline algae resulted in a abundant but species-poor fauna, while an almost monospecific turf of Gigartina was poor in both species and number of molluscan fauna.     

Contribution to the taxonomy and ecology of the Azorean benthic marine algae

Algal zonation patterns were studied in two sites (Caloura, south coast and Ribeirinha, north coast) of the island of Sao Miguel, Azores. At each site two stations were studied and the transects revealed the occurrence of two distinct and well established algal zones. In the first zone, daily immersed and emersed by the tide, the algae were growing in a dense and short tangle forming a mat, referred to as algal turf. In the second zone, which was wet most of the time, the algae were larger and frondose. A list of the species of benthic marine algae occurring on the algal turf of each station is given. Of the total of 47 species found, eight are new for the Azores and another 13 species are recorded for the first time for Sao Miguel. Gigartina acicularis (Roth) Lamouroux and articulate coralline algae (Corallina oficinalis Linnaeus and Jania spp.) were the more common species. Seasonal variation of the algal turf was studied and related to mean monthly values of air and sea water temperatures, insolation and hours of light. The zonation patterns and composition of algal species were compared with those from other open rocky shores.     

Differential colonization causing non-random forest plant community structure in a fragmented agricultural landscape

We investigated forest plant community structure of recent forest patches in a highly fragmented agricultural landscape, A nestedness analysis has been performed at The community level and at the individual species level. We tested the hypothesis that plant species composition showed a nested structure and whether this was generated by isolation and differential colonization. Alternative hypotheses formulated in the past, such as nested habitats and patch area dependent species relaxation, are verified. Isolation measures were calculated between clearly defined source and target patches. At the community level target patches are defined as forest patches < 35 yr old while older patches are considered as source patches. At the individual species level we distinguished between actually occupied and potentially suitable target patches based on a habitat space model and only occupied source patches are taken into account.
All results point out that the nested community pattern in recent forest patches is generated primarily by isolation and differential colonization. These findings are confirmed at the species level, since the degree of nestedness of the individual species is highly correlated with their isolation sensitivity.
Logistic regression analyses prove that many forest plant species are sensitive to isolation. The probability of occurrence of the isolation sensitive species drops almost to zero, when the nearest source patch is situated further than 200 m. Probabilities of colonization increase significantly when source patches are situated adjacent to target patches.     

Grazing effects in macroalgal communities depend on timing of patch colonization

Rocky macroalgal assemblages are typically composed of patches differing in age and species composition and grazing is generally a very important modifier of such assemblages. We hypothesized that patch colonization time determines its algal community and that grazing effects depend on the colonization time and vary with depth. We created patches by placing empty substrates at two sublittoral depths over five consecutive months, manipulated grazer entry and determined the algal species composition in each patch in the next growing season. Distinct algal colonization periods resulted in different algal assemblages. Although algal communities in our study area consist mainly of opportunistic species, thus being highly dynamic, the resulting macroalgal assemblages differed in species richness, diversity, composition, and total biomass even a year after first colonization. Substrates close to the water-surface supported a higher species richness and diversity than those in the deeper littoral. The community characteristics, total density, total biomass and species richness were only slightly, if at all affected by grazing. However, individual algal species or taxa showed varying and even contrasting responses to grazing, often differently between depths and depending on colonization time. In the deeper littoral, but not close to the water surface, grazing increased the density of filamentous brown algae while reducing the green alga Cladophora glomerata. In these taxa, grazing effects were strongest in patches colonized during the early growing season. Grazing at the colonization stage had lasting consequences for the density of several individual species.     

Global macroecology of bird assemblages in urbanized and semi‐natural ecosystems

Aim Despite the increasing pace of urbanization, little is known about how this process affects biodiversity globally. We investigate macroecological patterns of bird assemblages in urbanized areas relative to semi‐natural ecosystems. Location World‐wide. Methods We use a database of quantitative bird surveys to compare key assemblage structure parameters for plots in urbanized and semi‐natural ecosystems controlling for spatial autocorrelation and survey methodology. We use the term ‘urbanized’ instead of ‘urban’ ecosystems as many of the plots were not located in the centre of towns but in remnant habitat patches within conurbations. Results Some macroecological relationships were conserved in urbanized landscapes. Species–area, species–abundance and species–biomass relationships did not differ significantly between urbanized and non‐urbanized environments. However, there were differences in the relationships between productivity and assemblage structure. In forests, species richness increased with productivity; in both forests and open habitats, the evenness of species abundances declined as productivity increased. Among urbanized plots, instead, both species richness and the evenness of species abundances were independent of variation in productivity. Main conclusions Remnant habitats within urbanized areas are subject to many ecological alterations, yet key macroecological patterns differ remarkably little in urbanized versus non‐urbanized plots. Our results support the need for increased conservation activities in urbanized landscapes, particularly given the additional benefits of local experiences of biodiversity for the human population. With increasing urbanization world‐wide, broad‐scale efforts are needed to understand and manage the effects of this driver of change on biodiversity.     

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.