Distribution of egg strands of perch (<Emphasis Type="Italic">Perca</Emphasis> <Emphasis Type="Italic">fluviatilis</Emphasis> L.) with respect to depth and spawning substrate

Much of the historical Everglades has been either lost or degraded as a result of human activities. Among the aquatic habitats that comprise the Everglades landscape mosaic, open-water sloughs support critical ecological functions and appear especially sensitive to both hydrologic and water-quality perturbations. We used a combination of remote sensing and on-the-ground sampling to document spatial changes in the extent and vegetative composition of sloughs along a phosphorus (P) gradient in the northern Everglades. Increasing levels of water and soil P were associated with a decline in slough coverage, loss of the abundant native periphyton community, and a shift in dominant macrophyte species. The characteristic slough macrophyte species Eleocharis cellulosa and Nymphaea odorata exhibited different sensitivities to P enrichment, but both species declined with enrichment as slough habitats were invaded by Typha domingensis, a species that is known to expand aggressively in response to enrichment. A limited amount of open-water habitat occurred in highly enriched areas, but these habitats were maintained largely as a result of airboat disturbance and did not contain characteristic slough vegetation. Many changes in slough coverage and composition occurred in areas where water and soil P concentrations were only marginally higher than background levels. Our findings support the need for Everglades hydrologic restoration efforts to adhere to strict water-quality standards for P to avoid further degradation of this key landscape feature. Handling editor: L. M. Bini     

Reading the landscape: temporal and spatial changes in a patterned peatland

The Everglades of south Florida is a patterned peatland that has undergone major hydrologic modification over the last century, including both drainage and impoundment. The Everglades ridge and slough patterns were originally characterized by regularly spaced elevated ridges and tree islands oriented parallel to water flow through interconnected sloughs. Many areas of the remaining Everglades have lost this patterning over time. Historical aerial photography for the years 1940, 1953, 1972, 1984, and 2004 provides source data to measure these changes over six decades. Maps were created by digitizing the ridges, tree islands, and sloughs in fifteen 24 km² study plots located in the remaining Everglades, and metrics were developed to quantify the extent and types of changes in the patterns. Pattern metrics of length/width ratios, number of ridges, and perimeter/area ratios were used to define the details and trajectories of pattern changes in the study plots from 1940 through 2004. These metrics characterized elongation, smoothness, and abundance of ridges and tree islands. Hierarchical agglomerative cluster analysis was used to categorize these 75 maps (15 plots by 5 years) into five categories based on a suite of metrics of pattern quality. Nonmetric multidimensional scaling, an ordination technique, confirmed that these categories were distinct with the primary axis distinguished primarily by the abundance of elongated ridges in each study plot. Strong patterns like those described historically were characterized by numerous, long ridges while degraded patterns contained few large, irregularly shaped patches. Pattern degradation usually occurred with ridges fusing into fewer, less linear patches of emergent vegetation. Patterning improved in some plots, probably through wetter conditions facilitating expression of the underlying microtopography. Trajectories showing responses of individual study plots over the six decades indicated that ridge and slough patterns can degrade or improve over time scales of a decade or less. Changes in ridge and slough patterns indicate that (1) patterns can be lost quickly following severe peat dryout, yet (2) patterns appear resilient at least over multi-decadal time periods; (3) patterns can be maintained and possibly strengthened with deeper water depths, and (4) the sub-decadal response time of pattern changes visible in aerial imagery is highly useful for change detection within the landscape. This analysis suggests that restoration of some aspects of these unique peatland patterns may be possible within relatively short planning time frames. Use of aerial photography in future Everglades restoration efforts can facilitate restoration and adaptive management by documenting sub-decadal pattern changes in response to altered hydrology and water management.     

Ecological implications of extreme events: footprints of the 2010 earthquake along the Chilean coast

Deciphering ecological effects of major catastrophic events such as earthquakes, tsunamis, volcanic eruptions, storms and fires, requires rapid interdisciplinary efforts often hampered by a lack of pre-event data. Using results of intertidal surveys conducted shortly before and immediately after Chile's 2010 M(w) 8.8 earthquake along the entire rupture zone (ca. 34-38°S), we provide the first quantification of earthquake and tsunami effects on sandy beach ecosystems. Our study incorporated anthropogenic coastal development as a key design factor. Ecological responses of beach ecosystems were strongly affected by the magnitude of land-level change. Subsidence along the northern rupture segment combined with tsunami-associated disturbance and drowned beaches. In contrast, along the co-seismically uplifted southern rupture, beaches widened and flattened increasing habitat availability. Post-event changes in abundance and distribution of mobile intertidal invertebrates were not uniform, varying with land-level change, tsunami height and coastal development. On beaches where subsidence occurred, intertidal zones and their associated species disappeared. On some beaches, uplift of rocky sub-tidal substrate eliminated low intertidal sand beach habitat for ecologically important species. On others, unexpected interactions of uplift with man-made coastal armouring included restoration of upper and mid-intertidal habitat seaward of armouring followed by rapid colonization of mobile crustaceans typical of these zones formerly excluded by constraints imposed by the armouring structures. Responses of coastal ecosystems to major earthquakes appear to vary strongly with land-level change, the mobility of the biota and shore type. Our results show that interactions of extreme events with human-altered shorelines can produce surprising ecological outcomes, and suggest these complex responses to landscape alteration can leave lasting footprints in coastal ecosystems.     

The scaling of body size and mass in a host-parasitoid association: influence of host species and stage

We describe the allometry of body mass and body size as measured by hind-tibia length in males of Monoctonus paulensis (Ashmead) (Hymenoptera: Braconidae, Aphidiinae), a solitary parasitoid of aphids. To assess the influence of host quality on allometric relationships, we reared parasitoids on second and fourth nymphal instars of four different aphid species, Acyrthosiphon pisum (Harris), Macrosiphum creelii Davis, Myzus persicae (Sulzer) and Sitobion avenae (F.), under controlled conditions in the laboratory. Dry mass was positively correlated with hind-tibia length, and could be predicted from it, in unparasitized aphids, in aphid mummies containing parasitoid pupae, and in the parasitoid. The reduced-major-axis scaling exponents for the regression of dry mass on hind-tibia length were species-specific in aphids, reflecting differences in volume and shape between species. In mummified aphids, the stage at death influenced the size/mass relationship. In males of M. paulensis, the allometric exponent varied between parasitoids developing in different kinds of host. Individuals developing in pea aphid were absolutely larger in dry mass as well as proportionately larger relative to their hind-tibia length. We discuss the allometry of body size and body mass in relation to parasitoid fitness.     

Feeding on the edge: foraging White Ibis target inter‐habitat prey fluxes

Avian population dynamics are influenced by the availability of spatiotemporally variable prey resources, but the conditions producing abundant and accessible prey are not always clear. In the Florida Everglades, wading birds nest in the dry season when receding water levels concentrate prey and facilitate improved foraging efficiency. White Ibis (Eudocimus albus) feed extensively on crayfish in sloughs, and previous studies have demonstrated that crayfish move downgradient from higher elevation, heavily vegetated ridge habitats into adjacent less‐vegetated sloughs when ridges are almost dry. Most White Ibis foraging is thought to occur in sloughs with relatively shallow water (< 19 cm), but crayfish move and their densities peak when water in sloughs is deeper (~ 21–32 cm). We conducted an observational study of White Ibis foraging in drying wetlands to determine if White Ibis restricted their foraging to shallow water or if they foraged in relatively deep water when crayfish were migrating. In a series of large drying wetlands, we used time‐lapse imagery to quantify White Ibis foraging activity over 61 d from February to April 2017 and we also quantified crayfish biomass density in sloughs. Crayfish biomass density peaked when ridges were almost dry. Most White Ibis foraging occurred over 2–3 d when ridges were almost dry and water in sloughs averaged ≥ 29 cm deep. White Ibis selected slough edges for foraging, suggesting that they were capturing crayfish migrating between habitats. Our results point to a new mechanism of prey exploitation driven by inter‐habitat prey flux when ridge habitat dries. Although the results of previous studies suggest that White Ibis will not forage on fish in deeper water (> 25 cm), we found that White Ibis will forage on crayfish in water at those depths. Maintenance of habitat elevational differences and hydro‐patterns that promote crayfish production will be necessary to promote this predator–prey interaction in the ridge‐slough landscape of the Everglades.     

Benefits of adjacent habitat patches to the distribution of a crayfish population in a hydro-dynamic wetland landscape

Aquatic macrophyte patches are natural features of wetland ecosystems that serve as habitat for aquatic animals. Previous studies suggest animal densities in Everglades, USA, wetlands are generally less numerous in sawgrass ridges than in deeper lily sloughs. We studied the density distribution of a population of Procambarus fallax in ridge and slough habitat types over a 2-year period, spanning two wet–dry cycles and estimated growth and survival rates under flooded conditions to understand comparative value of each to the crayfish population. Procambarus fallax individuals inhabited and recruited in both marsh habitats. During periods of high water, crayfish densities were similar in both habitats; however, densities in both habitats varied seasonally, leading us to postulate some degree of population redistribution in response to fluctuating water depths. Analysis of size distributions over time revealed juveniles in both habitats and two major recruitment periods each year; distinct juvenile cohorts were present in early winter (Nov–Dec) and mid-summer (July–Aug). An in situ experiment of juvenile growth demonstrated that slough habitat type supported faster growth over ridge habitat. To understand habitat-specific mortality risk, a tethering study during flooded conditions indicated that relative predation risk by aquatic predators was greater in sloughs for all sizes and higher for smaller individuals in both habitats. The comparative importance of ridge and slough balances growth potential and survival probability during flooded conditions. This is the first study through time and across both habitat types analyzing the distribution and size structure of P. fallax population in the Everglades.     

Territory quality, survival and reproductive success in southern emu-wrens Stipiturus malachurus

Multi-factor analyses of territory quality in relation to fitness components of adults are rare, especially in non-migratory species. I studied the influence of multiple attributes of territory quality (habitat type and the abundance of food and predators) on the reproductive success and survival of a threatened Australian passerine, the southern emu-wren Stipiturus malachurus . The abundance of frequently-selected prey types (lepidoptera, diptera, hemiptera and larvae) varied significantly across territories according to habitat type. Reproductive success (number of offspring fledged) was highest in territories containing a greater proportion of tall shrubland, which had the highest insect abundance of any habitat. Closed heathland and sedge/rushland also had high food abundance compared to other habitat types, but higher fledging success occurred only within closed heathland, possibly because predator density was lower in this habitat type. High snake density was associated with reduced adult survival during the breeding season and a lower probability of nest success. In sedge/rushland, any benefits of prey abundance may therefore be offset by a high density of predators. Emu-wren age and size were unrelated to breeding output of pairs, suggesting that ecological factors may swamp effects of individual quality on emu-wren fitness components. Preservation of tall shrubland and closed heathland habitats appear to be of key conservation priority for emu-wrens.     

Geographical variation in allometry in the guppy (Poecilia reticulata)

Variation in static allometry, the power relationship between character size and body size among individuals at similar developmental stages, remains poorly understood. We tested whether predation or other ecological factors could affect static allometry by comparing the allometry between the caudal fin length and the body length in adult male guppies (Poecilia reticulata) among populations from different geographical areas, exposed to different predation pressures. Neither the allometric slopes nor the allometric elevations (intercept at constant slope) changed with predation pressure. However, populations from the Northern Range in Trinidad showed allometry with similar slopes but lower intercepts than populations from the Caroni and the Oropouche drainages. Because most of these populations are exposed to predation by the prawn Macrobrachium crenulatum, we speculated that the specific selection pressures exerted by this predator generated this change in relative caudal fin size, although effects of other environmental factors could not be ruled out. This study further suggests that the allometric elevation is more variable than the allometric slope.     

Hydraulic architecture and the evolution of shoot allometry in contrasting climates

We used pairs of congeneric shrub species from contrasting habitats to test for repeated evolutionary divergence in leaf-stem allometry and shoot hydraulic architecture in response to water availability. Allometric relationships and mean ratios between leaf size (individual and total area and mass per shoot) and stem cross-sectional area were compared between habitats using six species pairs representing three genera (Arctostaphylos, Baccharis, Ceanothus). We measured correlations among evolutionary changes in allometric, morphological, and physiological traits using phylogenetic independent contrasts. Allometric analysis revealed habitat differences: slopes were homogeneous among species (=1.46), but the more mesic-adapted species generally supported more leaf area at a common stem cross-sectional area. Reducing bivariate allometry to a ratio obscured this pattern because ratios varied with stem size, which was unrelated to habitat. Mean individual leaf size also was not correlated with either water availability or leaf-stem allometry. Stem hydraulic conductivity was generally lower in the xeric-adapted species of each pair, and its evolution mirrored changes in shoot allometry. This study provides evidence for repeated evolutionary divergence in shoot allometry and hydraulic architecture associated with water availability and demonstrates the importance of shoot allometry to water relations, independent of leaf size.     

Allometry of territory size and metabolic rate as predictors of self-thinning in young-of-the-year Atlantic salmon

1. Self-thinning is a progressive decline in population density caused by competitively induced losses in a cohort of growing individuals and can be depicted as: log₁₀ (density) = c − β log₁₀ (body mass).
2. In mobile animals, two mechanisms for self-thinning have been proposed: (i) the space hypothesis predicts that maximum population density for a given body size is the inverse of territory size, and hence, the self-thinning slope is the negative of the slope of the allometric territory-size relationship; (ii) the energetic equivalence hypothesis predicts that the self-thinning slope is the negative of the slope of the allometric metabolic rate relationship, assuming a constant supply of energy for the cohort.
3. Both hypotheses were tested by monitoring body size, population density, food availability and habitat for young-of-the-year Atlantic salmon ( Salmo salar ) in Catamaran Brook, New Brunswick. The results were consistent with the predictions of the space hypothesis. Observed densities did not exceed the maximum densities predicted and the observed self-thinning slope of −1·16 was not significantly different from the slope of −1·12, predicted by the allometry of territory size for the population under study.
4. The observed self-thinning slope was significantly steeper than −0·87, predicted by the allometry of metabolic rate, perhaps because of a gradual decline in food abundance over the study period. The decline in density was more rapid in very shallow sites and may have been partly caused by a seasonal change in water depth and an ontogenetic habitat shift rather than solely by competition for food or space.
5. The allometry of territory size may be a useful predictor of self-thinning in populations of mobile animals competing for food and space.     

Direct versus indirect effects of habitat fragmentation on community patterns in experimental landscapes

Habitat area and fragmentation are confounded in many ecological studies investigating fragmentation effects. We thus devised an innovative experiment founded on fractal neutral landscape models to disentangle the relative effects of habitat area and fragmentation on arthropod community patterns in red clover (Trifolium pratense). The conventional approach in experimental fragmentation studies is to adjust patch size and isolation to create different landscape patterns. We instead use fractal distributions to adjust the overall amount and fragmentation of habitat independently at the scale of the entire landscape, producing different patch properties. Although habitat area ultimately had a greater effect on arthropod abundance and diversity in this system, we found that fragmentation had a significant effect in clover landscapes with ≤40 % habitat. Landscapes at these lower habitat levels were dominated by edge cells, which had fewer arthropods and lower richness than interior cells. Fragmentation per se did not have a direct effect on local-scale diversity, however, as demonstrated by the lack of a broader landscape effect (in terms of total habitat area and fragmentation) on arthropods within habitat cells. Fragmentation—through the creation of edge habitat—thus had a strong indirect effect on morphospecies richness and abundance at the local scale. Although it has been suggested that fragmentation should be important at low habitat levels (≤20–30 %), we show that fragmentation per se is significant only at intermediate (40 %) levels of habitat, where edge effects were neither too great (as at lower levels of habitat) nor too weak (as at higher levels of habitat).     

Predicting bed shear stress and its role in sediment dynamics and restoration potential of the Everglades and other vegetated flow systems

Entrainment of sediment by flowing water affects topography, habitat suitability, and nutrient cycling in vegetated floodplains and wetlands, impacting ecosystem evolution and the success of restoration projects. Nonetheless, restoration managers lack simple decision-support tools for predicting shear stresses and sediment redistribution potential in different vegetation communities. Using a field-validated numerical model, we developed state-space diagrams that provide these predictions over a range of water-surface slopes, depths, and associated velocities in Everglades ridge and slough vegetation communities. Diminished bed shear stresses and a consequent decrease in bed sediment redistribution are hypothesized causes of a recent reduction in the topographic and vegetation heterogeneity of this ecosystem. Results confirmed the inability of present-day flows to entrain bed sediment. Further, our diagrams showed bed shear stresses to be highly sensitive to emergent vegetation density and water-surface slope but less sensitive to water depth and periphyton or floating vegetation abundance. These findings suggested that instituting a pulsing flow regime could be the most effective means to restore sediment redistribution to the Everglades. However, pulsing flows will not be sufficient to erode sediment from sloughs with abundant spikerush, unless spikerush density first decreases by natural or managed processes. Our methods provide a novel tool for identifying restoration parameters and performance measures in many types of vegetated aquatic environments where sediment erosion and deposition are involved.     

人为干扰栖息地退化对潮间带中华鲎幼鲎种群数量的影响

栖息地退化是中华鲎（Tachypleus tridentatus）面临的主要威胁因素。然而,人类活动和中华鲎栖息地退化之间的关系研究尚且不足。为了厘清人类活动对中华鲎幼鲎栖息地退化的影响,以北部湾潮间带为研究范围,于2014、2017和2020年对潮间带中华鲎幼鲎丰度进行随机样方法调查,并获取对应年份遥感影像（分辨率30m）作为数据源,借助GIS空间分析、景观格局分析和人为干扰度指数（human disturbance index,HDI）模型,量化评估人为干扰对北部湾潮间带中华鲎幼鲎栖息地景观格局及种群丰度的影响。结果表明：（1）2014-2020年,北部湾潮间带幼鲎栖息地退化严重,无干扰类型景观面积逐渐减少,大部分转化为养殖;（2）北部湾潮间带人为干扰逐渐加强,无干扰等级HDI指数面积不断减少,潮间带大部分面积HDI指数呈增强趋势;（3） HDI指数与幼鲎种群丰度呈显著负相关性,HDI指数高值斑块不适合幼鲎生存。依据HDI指数动态变化及空间分布,可为潮间带中华鲎幼鲎种群栖息地景观格局优化及鲎人工放流增殖选址等保护行动提供理论依据。     

Allometric escape from acoustic constraints is rare for frog calls

Allometric constraint is a product of natural selection and physical laws, particularly with respect to body size and traits constrained by properties thereof, such as metabolism, longevity, and vocal frequency. Allometric relationships are often conserved across lineages, indicating that physical constraints dictate scaling patterns in deep time, despite substantial genetic and ecological divergence among organisms. In particular, acoustic allometry (sound frequency ~ body size) is conserved across frogs, in defiance of massive variation in both body size and frequency. Here, we ask how many instances of allometric escape have occurred across the frog tree of life using a Bayesian framework that estimates the location, number, and magnitude of shifts in the adaptive landscape of acoustic allometry. Moreover, we test whether ecology in terms of calling site could affect these relationships. We find that calling site has a major influence on acoustic allometry. Despite this, we identify only four major instances of allometric escape, potentially deriving from ecomorphological adaptations to new signal modalities. In these instances of allometric escape, the optima and strength of the scaling relationship are different than expected for most other frog species, representing new adaptive regimes of body size ~ call frequency. Allometric constraints on frog calls are highly conserved and have rarely allowed escape, despite frequent invasions of new adaptive regimes and dramatic ecomorphological divergence. Our results highlight the rare instances in which natural and sexual selection combined can overcome physical constraints on sound production.     

Numerical allometric growth of the ommatidia,antennal sensilla,and teeth of foretibial combs in the milkweed bug Oncopeltus fasciatus Dallas (Heteroptera : Lygaeidae)

Oncopeltus fasciatus (Heteroptera : Lygaeidae), the milkweed bug, was bred in captivity. Sampling showed that individuals grow exponentially through their 6 developmental stages with an average linear increase per molt of 42% for the females and 41% for the males. The number of ommatidia per eye grows with negative allometry from an average of 30 in the first instar to 860 in the male and 820 in the female adult. The total number of sensilla on the 2 flagellar segments of an antenna increases with negative allometry during the 5 nymphal stages from a mean of 239 in the first instar to 2462 in the last. At this point, this allometric growth pattern is sharply broken by distinct numerical increase to 7163 on the adult flagellum. The number of teeth composing the foretibial comb, the tool for grooming the distal flagellar segment, grows with negative allometry through all 6 developmental stages. Calculations using previously published data from the migratory locust, Locusta migratoria, revealed the same growth pattern of antennal sensilla: uniform allometric growth during the nymphal development, broken by a conspicuous upward jump to the adult number of sensilla. In the American cockroach, Periplaneta americana, this growth pattern of antennal sensilla holds only for the male; the female continues the nymphal allometric growth into the adult stage. These observations on allometric growth fit three theoretical explanations: 1. Smooth allometric growth is evidence for an aut-adaptation to increasing size. 2. Ex-adaptations to novel ecological niches cause breaks in allometric growth patterns. 3. Chapman's rule, which states that increased mobility correlates with greater olfactory sensitivity, correctly predicts the observed breaks in the allometric growth patterns in the abundance of antennal sensilla.     

盐沼湿地大规模恢复的概念生态模型——以盐城为例

大规模湿地生态恢复是一项耗资巨大、复杂的系统工程,需要以整个区域湿地结构和功能恢复作为基本目标,将时间和空间上分散的研究成果进行系统梳理,形成对区域湿地生态变化及其驱动因素的规律性认识。本研究以盐城盐沼湿地为案例,以1987年作为未干扰或干扰较少的状态,从结构-过程-功能耦合作用角度,确定区域湿地恢复的关键生态特征,包括:健康与动态潮间带湿地系统、碱蓬生态系统生产力与弹性、复杂景观镶嵌与相互作用、潮间带底栖动物丰富与鸟类觅食基地,以及濒危与关键水鸟种群保护。在此基础上,将围垦与土地利用、水管理、全球变化与海平面上升作为驱动区域湿地生态变化的三大外部因素;海岸侵蚀与沉积、区域水格局变化、地形地貌变化、湿地空间变化与连通性丧失,以及互花米草入侵等是影响湿地生态系统变化的内在压力因子;基于这些压力因子与湿地生态系统变化之间复杂作用关系分析,形成了外部驱动力-内在压力源-生态影响-生态特征之间联合作用下的区域湿地恢复概念生态模型。此模型以复杂因果关系研究为基础,直观展示了湿地恢复需要去除或减缓各种压力因子的一般路径,有利于指导大规模盐沼湿地恢复规划与实践。     

Spatial and Temporal Considerations in Restoring Habitat for Wildlife

An accumulated body of theory and empirical evidence suggests that habitat selection by animals is a scale‐dependent, hierarchical process. Hierarchy theory predicts that habitat suitability is influenced by the interaction of factors at multiple spatial scales from the microsite to the landscape and that higher‐order factors impose constraints at lower levels. For instance, large‐scale factors such as landscape context may make a site unsuitable for a species even if the vegetation structure and composition are appropriate. In addition, the spatial arrangement of habitat elements at all scales must be considered when planning restoration efforts. For example, the presence of snags does not ensure that the site will be suitable for snag‐dependent species. The size, age, and spacing of snags and their juxtaposition to other habitat elements must also be considered. Finally, all habitats are dynamic, and therefore the ecological processes that contribute to those dynamics must be maintained or suitable substitutes included in the recovery plan. When considering restoring habitat for wildlife, we recommend that managers: (1) identify the wildlife species they want to target for restoration efforts, (2) consider the size and landscape context of the restoration site and whether it is appropriate for the target species, (3) identify the habitat elements that are necessary for the target species, (4) develop a strategy for restoring those elements and the ecological processes that maintain them, and (5) implement a long‐term monitoring program to gauge the success of the restoration efforts.     

The allometric pattern of sexually size dimorphic feather ornaments and factors affecting allometry

The static allometry of secondary sexual characters is currently subject to debate. While some studies suggest an almost universal positive allometry for such traits, but isometry or negative allometry for nonornamental traits, other studies maintain that any kind of allometric pattern is possible. Therefore, we investigated the allometry of sexually size dimorphic feather ornaments in 67 species of birds. We also studied the allometry of female feathers homologous to male ornaments (female ornaments in the following) and ordinary nonsexual traits. Allometries were estimated as reduced major axis slopes of trait length on tarsus length. Ornamental feathers showed positive allometric slopes in both sexes, although that was not a peculiarity for ornamental feathers, because nonsexual tail feathers also showed positive allometry. Migration distance (in males) and relative size of the tail ornament (in females) tended to be negatively related to the allometric slope of tail feather ornaments, although these results were not conclusive. Finally, we found an association between mating system and allometry of tail feather ornaments, with species with more intense sexual selection showing a smaller degree of allometry of tail ornaments. This study is consistent with theoretical models that predict no specific kind of allometric pattern for sexual and nonsexual characters.     

Passive restoration in Araucaria Forest: useful ecological indicators in monitoring successional advancement in exotic tree plantation landscapes

Monitoring successional advancement is a complex field involving a constant search for applied ecological indicators which facilitate monitoring of secondary forests for both active and passive restoration. In this study, the authors investigate the successional advancement of floristics and tree structure within Araucaria Forest (AF) fragments under passive restoration in a context where exotic tree plantations (mainly Pinus L. genus) dominate the landscape. The ecological indicators used were floristic dissimilarity (β‐diversity inferences), indicator species, ecological groups of species, basal area, and species abundance distribution (SAD) models (α‐diversity inferences). A total of 182 tree species belonging to 91 genera and 43 botanical families were identified. A high β diversity was verified for which each site has indicator species (for the locations CD—Dicksonia sellowiana; CO—Cryptocarya aschersoniana; and PG—Pinus taeda), where pioneer species contributed to much of the abundance. Different SAD models are useful for describing passive restoration sites in exotic tree plantation landscapes, namely Lognormal, Mandelbrot, and Zipf. SAD models together with basal area, taxonomic group (e.g. Myrtaceae assemblage), and tree abundance in ecological groups are strategic ecological indicators for monitoring successional advancement in AF.