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In this paper, landscape ecological risk in Qinling Mountain was studied. Using the remote sensing images of Landsat TM and DEM data in 1984, 2000, 2005, and 2014, an ecological risk assessment model was constructed, and landscape ecological risk indexes were calculated for four time periods 1984, 2004, 2005 and 2014. The spatial distribution of ecological risk was obtained with ArcGIS and geostatistics, and changes in the landscape patterns and spatiotemporal characteristics of ecological risk were analysed. As shown in the results; (a) from 1984 to 2014, the landscape pattern index of Qinling forest area was relatively stable; fragmentation and segregation decreased, and dominance and area increased. The fragmentation and separation of cultivated land increased over time, and the geographical distribution of cultivated land diversified, while its dominance decreased. (b) The areas of extremely low and extremely high ecological risk level in the study area is gradually reduced. But the area of high ecological risk level increased obviously. The extremely high ecological risk area was mainly distributed in the middle and south‐eastern regions. The extremely low and low risk areas were mainly distributed in the low hilly areas of northern Qinling. [ABSTRACT FROM AUTHOR]

A data set of common forest metrics was prepared using inventory data from Ecological Reserves in Maine, northeastern USA. An Ecological Reserve is generally defined as an area where timber harvesting does not occur and natural disturbance events are allowed to proceed without significant human influence. Beginning in the early 2000s, permanent, long term monitoring plots were established in Reserves across Maine. To date, 50 Reserves occupying approximately 70,820 ha with a total of 1,103 monitoring plots comprise Maine's Ecological Reserve System. A goal of the Ecological Reserve Monitoring program is to remeasure plots every 10 years and about half of the plots have been remeasured since the initial inventory. Stand metrics were calculated for both monitoring rounds and include: live tree basal area, live tree density, large (diameter at breast height, dbh ≥40 cm) and very large (dbh ≥51 cm) live tree density, standing dead tree density, large (dbh ≥40 cm) and very large (dbh ≥51 cm) standing dead tree density, total and large (diameter at transect intersect ≥40 cm) downed coarse woody debris volume, as well as various stand dynamic metrics. For comparison, the same metrics were computed for managed forests in Maine using permanent plot data from the US Department of Agriculture, Forest Service, Forest Inventory and Analysis (FIA) Program. Information on Ecological Reserve monitoring plots includes Ecological Reserve name, forest‐type group, geographic location, elevation, slope, aspect, and harvest history. This data should prove invaluable for assessing and evaluating long‐term changes in Ecological Reserves across the broad ecological/climate zones that are present in Maine. No copyright or proprietary restrictions are associated with the use of this data set other than citation of this Data Paper. These data are freely available for non‐commercial scientific use. [ABSTRACT FROM AUTHOR]

Several boreal insect species respond to smoke and heat generated by forest fires and use recent burns to reproduce in high numbers. Some of these species are rare or uncommon in undisturbed forests, and the contribution of recently burned habitats to their population dynamics has been deemed crucial by some to their long-term persistence. Consequently, the severe decline seen in some species in Fennoscandia has been frequently linked with fire suppression. In this paper, we explore some aspects of the spatial dynamics of pyrophilous insect populations in relation to the expected relative contribution of burned and unburned habitats to their global population dynamics. Forest fires are, throughout the boreal forest biome, generally highly aggregated in some years while rare in most other years. The low connectivity between fire events and the typical life cycle seen in these species make it improbable that recent burns act as significant population sources. This leads us to suggest that populations of pyrophilous species may be more limited by the adequacy of the unburned matrix than by the occurrence of fire events. Moreover, by combining an age-class distribution model and a dead wood availability model, we show that the quality of the unburned matrix increases in landscapes with longer fire cycles, in which pyrophilous insects should persist at higher population levels. We conclude that the degradation of the unburned habitat better explains the decline of pyrophilous insects than fire suppression alone. [ABSTRACT FROM AUTHOR]

Aim: On the basis of 2402 phytoecological relevés, with complete species lists, and real pH measurements resulting from chemical analyses of the top layer of forest soils, this paper compares quantitatively the ecological response of 46 herbaceous forest species along a pH gradient in two regions of northern France. Location: The two regions investigated are oceanic north-western France (NW) and semicontinental north-eastern France (NE). Methods: For each of the 46 species with more than 50 occurrences in both NW and NE regions, an ecological response curve was computed with simple logistic regression models, and two synthetic numerical values were derived: ecological optimum (OPT) and ecological amplitude (AMP). A comparison of the ecological behaviour of species present in both regions was performed in terms of shift in optimum and/or amplitude. Results: All 46 species did reveal a reaction to pH. Our main observation was the relative stability of the behaviour of most species with reference to pH conditions, which is consistent with results from some previous studies. Slight differences regarding the two synthetic parameters (OPT and AMP) were however observed between the NW and NE regions, probably due to a form of competitive release in neutral environments in the NW. Main conclusions: Among the main possibilities that could explain a geographical shift in the ecological behaviour of herbaceous species, competitive effects are, we suggest, the most plausible explanation. In the light of former studies, it seems that further analyses of geographical shifts in the ecological behaviour of forest plant species over large areas are needed, such as for example over the European continent. Nomenclature: Tutin et al . (2001). [ABSTRACT FROM AUTHOR]

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1. This paper explores the idea that functional heterogeneity (variability of a system property affecting ecological processes) is only a fraction of the available structural heterogeneity (variability of a property measured without reference to ecological effects) caused by non-random propagule dispersal. We report the effect of acorn dispersal by jays on the light environment experienced by Holm Oaks (Quercus ilexL.) during early recruitment in a Mediterranean montane forest.2. Four light variables were estimated by studying hemispherical photographs: direct site factor (DSF); indirect site factor (ISF); and potential direct radiation during April (PDRApril) and August (PDRAugust). Means and variances of these variables were compared before and after the dispersal of acorns by jays.3. The landscape occupied by Holm Oaks was very heterogeneous, which translated into differences in the available light among microhabitats of up to one order of magnitude.4. Because of the spatial pattern of acorn dispersal, the light environment of the oaks during their establishment was much more homogeneous than that in the whole landscape.5. This demonstrates that the heterogeneity relevant for plant recruitment is not necessarily that of the landscape as a whole.Functional Ecology(2004)18, 787–792 [ABSTRACT FROM AUTHOR]

The article offers information on the institutional factors which can effect the biophysical outcomes in forest management. According to the data analyzed from 46 forests located in six countries, active monitoring and sanctioning by locals is associated with positive forest conditions. It is found that conditions in community-managed forests are statistically same with that of government or privately-managed forests. Therefore, positive forests conditions can be achieved by the contribution of local communities with a focus on full management responsibilities.

The article discusses a study about the backward-facing step flow analogy of the structure of turbulence in a tall forest edge. This paper focuses on the flow disturbances near tall forest edges which are investigated by scholars in ecology, forest management, meteorology and fluid mechanics. The authors argue that the existing framework of forest canopy turbulence structure does not go in general with dense forested edges. They point out that the flow have several attributes in backward-facing step (BFS) flow. Analogies are presented in terms of rotor-like circulations.

In landscapes subject to intensive agriculture, both soil fertility and vegetation disturbance are capable of impacting strongly, evenly and simultaneously on the herbaceous plant cover and each tends to impose uniformity on the traits of constituent species. In more natural and ancient grasslands greater spatial and temporal variation in both productivity and disturbance occurs and both factors have been implicated in the maintenance of species-richness in herbaceous communities. However, empirical data suggest that disturbance is the more potent driver of trait differentiation and species co-existence at a local scale. This may arise from the great diversity in opportunities for establishment, growth or reproduction that arise when the intensity of competition is reduced by damage to the vegetation. In contrast to the diversifying effects of local disturbances, productivity-related plant traits (growth rate, leaf longevity, leaf chemistry, leaf toughness, decomposition rate) appear to be less variable on a local scale. This difference in the effects of the productivity and disturbance filters arises from the relative constancy of productivity within the community and the diversity in agency and in spatial and temporal scales exhibited by disturbance events. Also, evolutionary responses to disturbances involve minor adaptive shifts in phenological and regenerative traits and are more likely to occur as micro-evolutionary steps than the shifts in linked traits in the core physiology associated with the capacity to exploit productive and unproductive habitats. During the assembly of a community and over its subsequent lifespan filters with diversifying and convergent effects may operate simultaneously on recruitment from the local species pool and impose contrasted effects on the similarity of the trait values exhibited by co-existing species. Moreover, as a consequence of the frequent association of productivity with the convergence filter, an additional difference is predicted in terms of the effects of the two filters on ecosystem functioning. Convergence in traits selected by the productivity filter will exert effects on both the plant community and the ecosystem while divergent effects of the disturbance filter will be restricted to the plant community. [ABSTRACT FROM AUTHOR]

Field studies have shown that elevated CO2 can cause increased forest growth over the short term (<6 years) even in the face of N limitation. This is facilitated to some degree by greater biomass production per unit N uptake (lower tissue N concentrations), but more often than not, N uptake is increased with elevated CO2 as well. Some studies also show that N sequestration in the forest floor is increased with elevated CO2. These findings raise the questions of where the ‘extra’ N comes from and how long such growth increases can continue without being truncated by progressive N limitation (PNL). This paper reviews some of the early nutrient cycling literature that describes PNL during forest stand development and attempts to use this information, along with recent developments in soil N research, to put the issue of PNL with elevated CO2 into perspective. Some of the early studies indicated that trees can effectively ‘mine’ N from soils over the long term, and more recent developments in soil N cycling research suggest mechanisms by which this might have occurred. However, both the early nutrient cycling literature and more recent simulation modeling suggest that PNL will at some point truncate the observed increases in growth and nutrient uptake with elevated CO2, unless external inputs of N are increased by either N fixation or atmospheric deposition. [ABSTRACT FROM AUTHOR]

Field studies have shown that elevated CO2 can cause increased forest growth over the short term (<6 years) even in the face of N limitation. This is facilitated to some degree by greater biomass production per unit N uptake (lower tissue N concentrations), but more often than not, N uptake is increased with elevated CO2 as well. Some studies also show that N sequestration in the forest floor is increased with elevated CO2. These findings raise the questions of where the ‘extra’ N comes from and how long such growth increases can continue without being truncated by progressive N limitation (PNL). This paper reviews some of the early nutrient cycling literature that describes PNL during forest stand development and attempts to use this information, along with recent developments in soil N research, to put the issue of PNL with elevated CO2 into perspective. Some of the early studies indicated that trees can effectively ‘mine’ N from soils over the long term, and more recent developments in soil N cycling research suggest mechanisms by which this might have occurred. However, both the early nutrient cycling literature and more recent simulation modeling suggest that PNL will at some point truncate the observed increases in growth and nutrient uptake with elevated CO2, unless external inputs of N are increased by either N fixation or atmospheric deposition. [ABSTRACT FROM AUTHOR]

The article focuses on lichen colonization. Branches are well suited for studying lichen colonization as new substrate is added to the branch each year. However, few papers have focused on ecology and dynamics of lichen colonization, and no earlier publications have focused on how environmental changes, caused by logging, influence diaspore attachment and establishment in boreal spruce forests. Increased knowledge about how forestry influences lichen colonization is a prerequisite for developing appropriate forestry methods aimed to maintain species diversity. The survival of a lichen population is influenced by the species' ability to reproduce, to colonize new substratum, and to grow under changing environmental conditions. Foliose and fruticose epiphytic lichens in boreal spruce forest reproduce mainly asexually by dispersal of vegetative diaspores. Vegetative diaspores, such as soredia and isidia, are generally considered advantageous for rapid colonization on the substratum. However, poor dispersal of diaspores has often been postulated as limiting for development of populations of different epiphytic species.

Data are presented from pollen analytical investigations of an upland basin peat site (GWC) at c. 395 m.o.d. on Cefn Gwernffrwd, mid-Wales, 15 km north of Llandovery and 15 km south-east of Tregaron Bog. The data are presented in an outline radiocarbon-dated pollen diagram, covering more than 9500 radiocarbon years and zoned in the conventional manner, and in a detailed pollen diagram covering Atlantic and Sub-Boreal times, divided into eight phases. The evidence indicates that pine (Pinus) was not a major post-glacial forest component in this locality, but that hazel (Corylus) may have dominated the upland plateau woods for much of the Boreal. The composition of the Mesolithic forest is discussed and compared with neighbouring areas of the British Isles in the light of this apparent abundance of Corylus and with regard to its migration route into mid-Wales in the Flandrian.. The date for the elm (Ulmus) decline horizon at site GWC is within the expected range and consistent with that obtained from Tregaron Bog. The site is 0.5 km from a recently discovered prehistoric complex of presumed Bronze Age date. Although there is firm evidence for Neolithic clearances, the impact on the forest in this locality was more severe in the Bronze Age. This is apparently at variance with sites elsewhere in mid-Wales, where an open upland landscape has been claimed since the early Neolithic, and more closely parallels findings in Northern Ireland. [ABSTRACT FROM AUTHOR]

Information about several papers discussed at a conference sponsored by the Tropical Group is presented. Topics include the classification of South-East Asian tropical lowland vegetation using climate and soil , the problems in studying the fauna of soil and allied habitats in the rain forest of Solomon Islands, and land molluscs of the Solomon Islands.

The article discusses the experiment results of the distribution of growth-form in a deciduous wood. There are two species of major importance in the deciduous wood chosen for this study classify into the group named Wefts, composed of robust mosses with ascending and twisted shoots. The other one falls into the group named Mats described as "thread-like." The studies also show that growth-form representation of mosses in the ground-stratum manifests the states of illumination in a deciduous woodland community. The microclimatic variations that distinguish the prevalence of species of related growth-form types are predominately associated with the shading effects of the field-stratum.

The article focuses on the ecology and plant distribution pattern of the Forty Acre Wood,in Chippenham Fen. It mentions that the Wood gives the clearest evidence of the operation of drainage factors upon the fen. It describes the woody and herbaceous vegetation occurring in the three zones in the area and states that the relative tolerance of the different tree species to ill-drainage is indicated by the distribution of trees in the zones. The alterations in the woodland brought about by varying drainage periods is also discussed.

This section presents abstracts on the vegetation and ecology of the overseas empire and on related topics, including "The Forests of the Pacific Coasts of British Columbia and Southeastern Alaska," by J. W. Harshberger, "Notes on Some Forest (Site) Types in North America," by Y. Ilvessalo, and "A Study of the Genus Clarkia With Special Reference to its Relationship to Godetia," by P. A. Munz and C. L. Hitchcock.

The article provides an overview of various articles related to ecology. "Experimental Vegetation," by F. E. Clements and J. E. Weaver, and "The Phytometer Method in Ecology," by F. E. Clements and G. W. Goldsmith, discusses the results of an attempt to use plants, or plant communities, as the best measures of reaction to the habitat, in ecological studies. "Density of Cell Sap in Relation to Environmental Conditions in the Wasatch Mountains, Utah," by C. F. Korstian, investigated the relations of plants to the conditions of the environment, with emphasis on forestry and forest regeneration. "The Distribution of Pisidia in the Oakamoor District of the Churnet Valley," by W. E. Alkins, offers a detailed study of the ecological relations of small bivalve mollusca.

Information about the British Ecological Society's Tropical group meeting held at the Westfield College in London, England on November 2, 1965 is presented in which the topic for discussion was the temperature as a factor in tropical ecology. Also, the event gave emphasis on the main contributions in ecology which include, papers about river fauna and forests.

Recent studies have demonstrated the potential of lidar‐derived methods in plant ecology and forestry. One limitation to these methods is accessing the information content of point clouds, from which tree‐scale metrics can be retrieved. This is currently undertaken through laborious and time‐consuming manual segmentation of tree‐level point clouds from larger‐area point clouds, an effort that is impracticable across thousands of stems.Here, we present treeseg, an open‐source software to automate this task. This method utilises generic point cloud processing techniques including Euclidean clustering, principal component analysis, region‐based segmentation, shape fitting and connectivity testing. This data‐driven approach uses few a priori assumptions of tree architecture, and transferability across lidar instruments is constrained only by data quality requirements.We demonstrate the treeseg algorithm here on data acquired from both a structurally simple open forest and a complex tropical forest. Across these data, we successfully automatically extract 96% and 70% of trees, respectively, with the remainder requiring some straightforward manual segmentation.treeseg allows ready and quick access to tree‐scale information contained in lidar point clouds. treeseg should help contribute to more wide‐scale uptake of lidar‐derived methods to applications ranging from the estimation of carbon stocks through to descriptions of plant form and function. [ABSTRACT FROM AUTHOR]

Plot‐based data collection is an important component of quantitative ecological research and is widely used. Some of the most extensive plot‐networks can be found in country‐wide forest inventories, which provide critical information about the state of forest ecosystems. While sampling designs for forest inventories have been well studied, plot design and installation has received less attention.The New Zealand National Forest Inventory of natural forest uses a nested plot design with a 0.126 ha circular plot superimposed concentrically on a 0.04 ha square plot. Stems ≥ 60 cm diameter at breast height (DBH) are measured in the circular plot while stems ≥ 2.5 DBH are measured in the square plot. Stem density of ≥60 cm DBH stems measured in the circular plots were compared with those from square plots.Stem densities estimated from square plot measurements were 23.7% higher than those estimated from circular plot measurements in the 2002–2007 inventory, and 18.4% higher in the 2009–2014 inventory. The main cause of this discrepancy appears to be due to the placement of plot boundaries during establishment of square plots. This effect may have resulted from a subconscious tendency of field teams to include large trees inside plots when laying out these boundaries. It is concluded that estimates from the circular plots are unlikely to be biased while those from the square plots are positively biased.This study highlights the critical importance of plot design and plot placement in forest inventories to ensure that estimates of stand attributes are unbiased. Especially on undulating or uneven terrain, methods of determining whether trees are inside or outside plot boundaries of circular plots are likely to be more accurate than those typically used for square or rectangular plots. [ABSTRACT FROM AUTHOR]

Vegetation restoration is a globally important form of management intervention designed to both remediate degraded land and to restore biodiversity. Using a 15‐year controlled experimental study in endangered Australian temperate woodlands, we quantified the response of bird biota to vegetation enhancement leading to the re‐establishment of an understorey, an increase in woodland patch size, or a combination of both. Our empirical results were characterized by marked variation in species richness and in the response of individual species to both time since enhancement and type of enhancement. For example, overall bird species richness initially responded negatively to enhancements but the effects were mitigated over time. Similar responses were identified for individual species such as the Rufous Songlark (Megalurus mathewsii). In the case of the Noisy Miner (Manorina melanocephala), responses to enhancement were negative and remained so over time. Conversely, the White‐plumed Honeyeater (Ptilotula penicillata), Yellow‐rumped Thornbill (Acanthiza chrysorrhoa) and Superb Fairy‐wren (Malarus cyaneus) responded positively to enhancements. We also found evidence for variable responses to the kind of enhancement with some species responding to increased woodland patch size (e.g. Yellow‐rumped Thornbill), others to a combination of enhancements (e.g. White‐plumed Honeyeater), whereas yet others were agnostic to the kind of intervention that was implemented (e.g. Noisy Miner). Positive effects of enhancement were often time lagged for 6–8 years following instigation of underplanting and/or increases in woodland patch size. The negative effects of patch enhancement on the Noisy Miner indicate that underplanting and/or increases in woodland patch size may represent ways in which the impacts on other bird taxa of this despotic, hyper‐aggressive species might be mitigated. [ABSTRACT FROM AUTHOR]

Understanding functional trait-environment relationships ( TERs) may improve predictions of community assembly. However, many empirical TERs have been weak or lacking conceptual foundation. TERs based on leaf venation networks may better link individuals and communities via hydraulic constraints. We report measurements of vein density, vein radius, and leaf thickness for more than 100 dominant species occurring in ten forest communities spanning a 3,300 m Andes-Amazon elevation gradient in Peru. We use these data to measure the strength of TERs at community scale and to determine whether observed TERs are similar to those predicted by physiological theory. We found strong support for TERs between all traits and temperature, as well weaker support for a predicted TER between maximum abundance-weighted leaf transpiration rate and maximum potential evapotranspiration. These results provide one approach for developing a more mechanistic trait-based community assembly theory. [ABSTRACT FROM AUTHOR]

Aim Climate change is expected to increase the frequency and intensity of extreme climatic events, such as severe droughts and intense rainfall periods. We explored how the avifauna of a highly modified region responded to a 13-year drought (the 'Big Dry'), followed by a two-year period of substantially higher than average rainfall (the 'Big Wet'). Location Temperate woodlands in north central Victoria, Australia. Methods We used two spatially extensive, long-term survey programmes, each of which was repeated three times: early and late in the Big Dry, and in the Big Wet. We compared species-specific changes in reporting rates between periods in both programmes to explore the resistance (the ability to persist during drought) and resilience (extent of recovery post-drought) of species to climate extremes. Results There was a substantial decline in the reporting rates of 42-62% (depending on programme) of species between surveys conducted early and late in the Big Dry. In the Big Wet, there was some recovery, with 21-29% of species increasing substantially. However, more than half of species did not recover and 14-27% of species continued to decline in reporting rate compared with early on in the Big Dry. Species' responses were not strongly related to ecological traits. Species resistance to the drought was inversely related to resilience in the Big Wet for 20-35% of the species, while 76-78% of species with low resistance showed an overall decline across the study period. Conclusions As declines occurred largely irrespective of ecological traits, this suggests a widespread mechanism is responsible. Species that declined the most during the Big Dry did not necessarily show the greatest recoveries. In already much modified regions, climate extremes such as extended drought will induce on-going changes in the biota. [ABSTRACT FROM AUTHOR]

This section presents abstracts of several research related to ecology and foreign vegetation published in different journals, including "Hawaii's Tapestry Forests," by Vaughan MacCaughey, "The Establishment of a Douglas Fir Forest,' by J. V. Hoffmann and "The Marine Algae of Guernsey," by Lilian Lyle.

Aim Climatic conditions exert a strong control on the geographic distribution of many woodland-to-grassland transition zones (or 'tree lines'). Because woody plants have, in general, a weaker cold tolerance than herbaceous vegetation, their altitudinal or latitudinal limits are strongly controlled by cold sensitivity. While temperature controls on the dynamics of woodland-grassland ecotones are relatively well established, the ability of woody plants to modify their microclimate and to create habitat for seedling establishment and growth may involve a variety of processes that are still not completely understood. Here we investigate feedbacks between vegetation and microclimatic conditions in the proximity to woodland-grassland ecotones. Location We concentrate on arctic and alpine tree lines, the transition between mangrove forests and salt marshes in coastal ecosystems, and the shift from shrubland to grassland along temperature gradients in arid landscapes. Methods We review the major abiotic and biotic mechanisms underlying the ability of woody plants to alter the nocturnal microclimate by increasing the temperatures they are exposed to. Results We find that in many arctic, alpine, desert and coastal landscapes the presence of trees or shrubs causes nocturnal warming thereby favouring the establishment and survival of woody plants. Main conclusion Because of this feedback, trees and shrubs may establish in areas that would be otherwise unsuitable for their survival. Thus, in grassland-woodland transition zones both vegetation covers may be (alternative) stable states of the landscape, thereby affecting the way tree lines may migrate in response to regional and global climate change. [ABSTRACT FROM AUTHOR]

Plant species turnover in central Panamanian forests has been principally attributed to the effects of dispersal limitation and a strong Caribbean to Pacific gradient in rainfall seasonality. Despite marked geological heterogeneity, the role of soil variation has not been rigorously examined., We modelled the compositional turnover of trees and ferns in the Panama Canal watershed as a function of soil chemistry, climate and geographical separation, using generalized dissimilarity models ( GDMs)., Predictability in both plant groups was strong, with 74% of turnover explained in trees and 49% in ferns. Major trends in the two plant groups were strikingly similar. The independent effects of soils, and of climate for trees, were sizeable, but those of geographical distance were minor. In both plant groups, distance and climatic effects on species turnover covaried strongly., Including floristic dissimilarity of the other taxon as a predictor increased explained deviance to 81% in trees and 59% in ferns. Controlling for differences in plant density among plots reduced deviance explained by climate and distance, while soil effects remained strong. Limiting the analyses to soils of volcanic origin increased deviance explained by climate, soils and distance, but their effects covaried strongly. Independent soil effects on tree turnover were reduced, but their effects on fern turnover remained pronounced., Dry season length was the most important climatic predictor for both taxa, and P and pH were the most important soil predictors. Particularly, rapid species turnover was associated with the driest end of the seasonality gradient, linked to declining individual densities and species richness, and with the low end of the phosphorus gradient., Synthesis. While changes in rainfall and seasonality undoubtedly limit plant distributions in this region, soil effects are at least as important, and interactions between the two are sizeable. This is likely to hold elsewhere in the Caribbean region, where mosaics of marine and volcanic soils combined with pronounced rainfall gradients are common. Strong congruence between our focal taxa suggests that our results can be extrapolated to other plant groups, particularly as trees and ferns are distantly related and represent different life-forms. [ABSTRACT FROM AUTHOR]

The degree to which turnover in biological communities is structured by deterministic or stochastic factors and the identities of influential deterministic factors are fundamental, yet unresolved, questions in ecology. Answers to these questions are particularly important for projecting the fate of forests with diverse disturbance histories worldwide. To uncover the processes governing turnover we use species-level molecular phylogenies and functional trait data sets for two long-term tropical forest plots with contrasting disturbance histories: one forest is older-growth, and one was recently disturbed. Having both phylogenetic and functional information further allows us to parse out the deterministic influences of different ecological filters. With the use of null models we find that compositional turnover was random with respect to phylogeny on average, but highly nonrandom with respect to measured functional traits. Furthermore, as predicted by a deterministic assembly process, the older-growth and disturbed forests were characterized by less than and greater than expected functional turnover, respectively. These results suggest that the abiotic environment, which changes due to succession in the disturbed forest, strongly governs the temporal dynamics of disturbed and undisturbed tropical forests. Predicting future changes in the composition of disturbed and undisturbed forests may therefore be tractable when using a functional-trait-based approach. [ABSTRACT FROM AUTHOR]

Species' responses to tropical forest fragmentation are variable and not well understood. Species' functional traits might help to reveal patterns of fragmentation sensitivity and provide valuable guidance to conservation practice. On the basis of 30 reviewed studies published between 1997 and 2008, we present a quantitative analysis of 730 responses of Neotropical vertebrates to forest fragmentation and habitat loss in terms of Species' presence, abundance or fitness. Our intention was to identify possible ecological predictors of sensitivity to fragmentation, such as vertebrate group, feeding guild, forest dependency, and body size. We also controlled for methodology and study site characteristics, i.e. parameters studied, study design, study ID, and site ID. These ecological and methodological variables are frequently hypothesized to have an influence on reported fragmentation sensitivity. We conducted Linear Mixed Model analyses in order to relate the potential predictor variables to reported fragmentation effects. Model performance was assessed on the basis of AIC values. The best models included feeding guild, feeding guild+study design and feeding guild+forest dependency, respectively. We found that study ID and site ID significantly improved the models. Post-hoc tests revealed that nectarivores, possibly herbivores, and species able to use open habitats were affected significantly less by forest fragmentation than others. We therefore conclude that Neotropical nectarivores that are able to use open habitats are less negatively affected by forest fragmentation. Furthermore, a study site's characteristics will always be crucial in explaining observed fragmentation effects. [ABSTRACT FROM AUTHOR]

Aim Working within a system of high structural contrast between fragments and the surrounding matrix, we assessed patterns of species loss and changes in species composition of phyllostomid bats on artificial land-bridge islands relative to mainland assemblages, and evaluated the responses of bats to forest edges. We further examined the relative influence of local-scale characteristics (e.g. vegetation structure, island area) versus landscape attributes (e.g. forest cover, patch density) and the importance of spatial scale in determining phyllostomid species richness and composition on islands. Location Islands in Gatún Lake and adjacent mainland peninsulas in the Barro Colorado Nature Monument, Panama. Methods Bats were sampled over a 2-year period on 11 islands as well as at forest-edge and interior sites on adjacent mainland, resulting in > 8400 captures. Results The islands harboured a less diverse and structurally simplified phyllostomid bat fauna. Islands far from the mainland were especially species-poor. This decline in species richness was associated with compositional shifts towards assemblages strongly dominated by frugivores with good dispersal abilities. Members of other ensembles, most importantly gleaning animalivores, were much less common or absent. Although overall species composition was not significantly altered, species richness at continuous forest-edge sites was significantly lower compared with that at interior sites. Distance from the mainland and amount of forest cover in the landscape were the best predictors of species richness and assemblage composition. Responses were scale-dependent. At the local scale, species richness was independent of island area but was correlated positively with distance from the mainland. In contrast, area effects became more important at larger spatial scales, suggesting that many species use multiple fragments. Main conclusions Our results underline the conservation value of small habitat remnants, which, even when embedded in a hostile matrix, can support a relatively diverse bat fauna, provided that there is a low degree of patch isolation and spatial proximity to larger tracts of continuous forest. Although the results at the assemblage level were inconclusive, we demonstrate that certain bat species and ensembles, particularly gleaning animalivores, exhibit high edge-sensitivity. Our results point to habitat loss rather than changes in landscape configuration as the main process after isolation underlying phyllostomid bat responses, suggesting that conservation efforts should focus on habitat preservation instead of trying to minimize fragmentation per se at the expense of habitat amount. [ABSTRACT FROM AUTHOR]

• Holocene vegetational dynamics along the prairie–forest border of Minnesota were first documented in McAndrews’ classic work. Despite numerous subsequent paleo-studies, a number of questions remain unanswered about the vegetation history of the region. Here, pollen, stable-isotope, mineral, and charcoal data are described from three lakes near McAndrews’ sites. These data were compared with other paleoenvironmental records to reconstruct vegetation, aridity, and fire. • The climate was relatively wet with increasing summer temperatures before ~8000 yr before present (BP). The rates of changes were asymmetric for the onset and termination of middle-Holocene aridity, with an abrupt increase at ~8000 yr BP and a gradual, but variable, decline from ~7800 to 4000 yr BP. • Early-Holocene coniferous forests changed to mixed-grass prairie without an intervening period of tallgrass prairie or deciduous forest, whereas the retreat of prairie was characterized by transitions from mixed-grass to tallgrass prairie to deciduous forest and finally to coniferous forest. Within the middle Holocene, the composition and structures of grass-dominated vegetation varied both temporally and spatially. • Fire primarily responded to changes in climate and fuel loads. Vegetation was more strongly influenced by climatic changes than by fire-regime shifts. [ABSTRACT FROM AUTHOR]

1. While various studies have evaluated the habitat requirements for wildlife in fragmented forest landscapes at multiple spatial scales, few have considered whether there is regional variation in the most important factors. This is a conundrum for managers of any species with a broad geographical range: to what extent should studies in one region inform decisions in another? 2. We addressed this question using a case study of the koala, Phascolarctos cinereus, in three biogeographically different fragmented forested landscapes in eastern Australia. Mixed-effect logistic models were applied to predict koala occurrence from explanatory variables captured at four spatial scales: the individual tree, the stand (<1 ha), the patch (1–100 ha) and the landscape (100–1000 ha). 3. We used model averaging to account for model and parameter uncertainty, and tested the cross-regional discrimination ability of the models. 4. We discovered that multiscale models of koala distribution cannot be readily generalized from region to region, and that specific conservation actions for each region, rather than the entire geographical range, are more appropriate. We found a strong justification for adopting a hierarchical landscape approach to koala conservation across its range. However, cross-regional differences in habitat relationships occurred within this hierarchy. Exceptions were landscape context, which showed a consistently strong effect and high rank in all regions, and the presence of individual preferred tree species of the genus Eucalyptus, which showed modest consistency in its interaction with large-diameter trees across the regions. In contrast, the remaining habitat variables, including patch size (a key management factor), showed moderate to strong cross-regional variation attributed to the interaction of edaphic factors, landscape history and contemporary land-use patterns. 5. Synthesis and applications. Adopting a uniform conservation programme over a large geographical area is attractive to policy-makers and conservation planners. However, our study confirms the lack of generality of species distribution models over large areas. Consequently, we argue against adopting a uniform conservation programme for species with a large geographical range. [ABSTRACT FROM AUTHOR]

The Madagascar spider tortoise Pyxis arachnoides is facing pressure from habitat destruction, hunting for food and collection for the exotic pet-trade. Very little is known of the biology and ecology of P. arachnoides. This study centres on a subspecies population of P. arachnoides arachnoides, within the southern dry forests of the Anakao region of southwest Madagascar . Surveys were carried out across 83, one hectare, quadrants over 12 months, during both the wet and dry seasons, with respective seasonal mean population densities recorded at 4.63 and 2.08 individuals per ha. This significant variation was accompanied by a variation in micro habitat preference between the seasons, with P. a. arachnoides moving to areas of greater vegetation cover during the warmer wet season. P. a. arachnoides was only recorded as feeding during the wet months, a period of increased activity. The subspecies became less active during the dry season, with some individuals entering a dormant phase. There was generally a greater abundance of females encountered throughout the year, usually weighing less than males. Juvenile abundance peaked during February and March. Six-year-old specimens were the most regularly encountered individuals and a mean age throughout the survey was recorded at 11.25 years. Résumé La Pyxide arachnoïde de Madagascar, Pyxis arachnoides, subit des pressions comprenant la destruction de son habitat, la chasse alimentaire et le prélèvement destiné au commerce d’animaux exotiques. On connaît très peu de la biologie et de l’écologie de P. arachnoides. Cette étude se focalise sur une population de la sous-espèce P. arachnoides arachnoides vivant dans la forêt sèche du sud, dans la région de l’Anakao au sud ouest de Madagascar. Des reconnaissances ont été menées dans 83 quadrats d’un hectare, durant 12 mois au cours des saisons sèche et humide, où l’on a relevé des densités moyennes saisonnières de respectivement 4,63 et 2,08 individus à l’hectare. Cette variation significative était assortie d’une variation dans la préférence de micro habitat entre les saisons, où P. a. arachnoides se déplace vers des zones à couvert végétal plus étendu durant la saison humide plus chaude. On n’a observé P. a. arachnoides s’alimenter que durant les mois humides durant laquelle son activité est plus importante. Cette sous-espèce devient moins active au cours de la saison sèche, où certains individus entrent en phase dormante. On a généralement constaté tout au long de l’année une plus grande abondance de femelles, qui pèsent habituellement moins que les mâles. L’abondance maximale de juvéniles se situe en février et mars. Les individus rencontrés le plus régulièrement étaient des spécimens âgés de six ans, et l’âge moyen enregistré tout au long de l’étude était de 11,25 ans. [ABSTRACT FROM AUTHOR]

Fruit abundance is a critical factor in ecological studies of tropical forest animals and plants, but difficult to measure at large spatial scales. We tried to estimate spatial variation in fruit abundance on a relatively large spatial scale using low altitude, high-resolution aerial photography. We measured fruit production for all 555 individuals of the arborescent palm Astrocaryum standleyanum across 25 ha of mapped tropical moist forest on Barro Colorado Island, Panama, by visually counting fruits from the ground. Simultaneously, we used high-resolution aerial photographs to map sun-exposed crowns of the palm across the same area, which were then linked to ground-mapped stems. First, we verified that the fruit crop size of individual trees was positively associated with both crown presence on aerial photos and crown area visible on aerial photos. Then, we determined how well spatial variation in Astrocaryum fruit density across the study area was predicted by spatial densities of photo-detected crowns and crown area compared to spatial densities of ground-mapped stems and stem diameters. We found a positive association of fruit crop size with crown visibility on aerial photographs. Although representing just one third of all individuals in the study area, photo-detected crowns represented 57% of all fruits produced. The spatial pattern of photo-detected crowns was strongly correlated with the spatial pattern of fruit abundance based on direct fruit counts, and correctly showed the areas with the highest and lowest fruit abundances. The spatial density of photo-detected crowns predicted spatial variation in fruit abundance equally well as did the spatial density of ground-mapped stems. Photo-detected crown area did not yield a better prediction. Our study indicates that remote sensing of crowns can be a reliable and cost-effective method for estimating spatial variation in fruit abundance across large areas for highly distinctive canopy species. Our study is also among the few to provide empirical evidence for a positive relationship between crown exposure of forest trees and fruit production. [ABSTRACT FROM AUTHOR]

1. We examined the effects of browsing by moose and snowshoe hares on vegetation structure, species composition, plant demography and element cycling in 25 riparian (willow) vegetation stands along the Tanana River, interior Alaska, across a 250-km gradient that represented a fivefold range in moose densities (0.2–1.0 km−2). 2. Browsing frequency was much greater in areas with high moose densities. The combined browsing pressure (% of annual browse production consumed by herbivores) of moose ( Alces alces) and snowshoe hares ( Lepus americanus) on forage species was over fivefold greater in the high moose density areas (33%) than the low moose density areas (6%), reflecting the fivefold difference in moose densities. 3. Above-ground biomass of preferred willow species was lower in high moose density areas, and the age structure of the vegetation was significantly skewed towards younger age classes. This shift in age structure was accompanied by higher proportion of dead to live ramets, indicating higher mortality under increased browsing pressure. Increasing browsing pressure favoured later-successional species ( Alnus tenuifolia and Populus balsamifera) on the landscape, as shown by both a reduction in the number and size of willow stands in high-density areas. 4. High rates of fecal input resulted in a doubling of above-ground N input in high moose density areas. The rates of carbon and nitrogen input from willow communities to the soil as mediated by moose herbivory were approximately fivefold and eightfold greater in high moose density areas than in low moose density areas, respectively. 5. Synthesis. The effects of herbivory were manifested at several ecological hierarchies, including the individual, the community, and the landscape. Across these spatial scales herbivory appears to accelerate the ecosystem turnover of carbon and nitrogen by a combination of both plant- and animal-based processes. [ABSTRACT FROM AUTHOR]

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Two woody Hypericum species ( H. roeparianum and H. revolutum) often coexist in forest edge and stream mantle communities in the Bamenda-Banoso Highlands, Cameroon. Morphologically nonspecialized flowers of both species are visited by specific eye-catching visitors. Nectarless flowers of H. roeparianum are visited by a large carpenter bee Xylocopa sp. ( Hymenoptera) and nectar-producing flowers of H. revolutum are the main source of nectar for sunbirds ( Cyanomitra oritis, Cinnyris reichenowi and C. bouvieri). Using a manipulative experiment, we showed that the carpenter bee plays an important role in the reproduction success of H. roeparianum, whereas sunbirds affect seed production of H. revolutum only little. We suggest that a clear differentiation of pollination niches enables the coexistence of both Hypericum species. The study showed that the pollination system of H. roeparianum with morphologically nonspecialized flowers can be ecologically specialized. Sunbirds are not decisive for the reproductive success of H. revolutum and thus have only little selection pressure on its floral traits. The results indicate the importance of reproduction success assessment in pollination studies. Résumé Deux espèces ligneuses d’ Hypericum (H. roeparianum et H. revolutum) coexistent souvent à la lisière des forêts et sont présentes dans les communautés qui recouvrent les Bamenda-Banoso Highlands, au Cameroun. Non spécialisées morphologiquement, les fleurs des deux espèces sont visitées par des hôtes spécifiques spectaculaires. Les fleurs sans nectar de H. roeparianum sont visitées par une grande abeille charpentière Xylocopa sp. (Hyménoptère), et les fleurs à nectar de H. revolutum sont la principale source de nectar pour les Souimangas ( Cyanomitra oritis, Cinniris reichenowi et C. bouvieri. Par une expérience de manipulation, nous avons montré que l'abeille charpentière joue un rôle important dans la réussite de la reproduction de H. roeparianum, alors que les Souimangas n'ont que peu d'effet sur la production de graines de H. revolutum. Nous suggérons qu'une nette différenciation des niches de pollinisation permet la coexistence des deux espèces d’ Hypericum. L’étude a montré que le système de pollinisation de H. roeparianum, qui a des fleurs qui ne sont pas morphologiquement spécialisées, peut être écologiquement spécialisé. Les Souimangas ne sont pas déterminants dans le succès de la reproduction de H. revolutum et n'exercent donc qu'une pression limitée sur la sélection de ses traits floraux. Les résultats indiquent l'importance de l’évaluation des succès de la reproduction dans les études de la pollinisation.) [ABSTRACT FROM AUTHOR]

The importance of disturbance for regulating the structure and diversity of grassy ecosystems is widely recognized, but disturbance-mediated interactions between grassland composition and grassland resilience, and consequent implications for conservation management, are less well documented. We established replicated burning, mowing and (non-livestock) grazing regimes in two contrasting grassy woodland remnants in south-eastern Australia, and monitored the dynamics and resilience of the matrix-forming tussock grasses, Poa sieberiana ( Poa) and Themeda australis ( Themeda) , over 12 years. Introduction of frequent burning to a Poa-dominated understorey in a rarely burnt woodland enhanced dominance by Themeda, and conversely, reduced fire frequency in a frequently burnt Themeda grassland substantially increased Poa abundance . Burning was potentially detrimental in the Poa-dominated woodland, but sward resilience (recovery after the 2002 burn) increased as Themeda increased with repeated burning. By contrast, the Themeda grassland was resilient to 4- and 8-yearly burning, but biennial burning led to poor resilience and high tussock mortality under drought conditions. Contrary to other mesic grasslands, cessation of burning had not caused sward collapse by 14 years post-fire despite high litter accumulation, potentially due to compensatory growth of Poa, lower site productivity and drought. Biennial mowing without slash removal was similar to 4-yearly burning in effects, while exclusion from kangaroo and rabbit grazing significantly increased sward biomass and contributed to increased Poa cover and inflorescence production. We conclude that functional complementarity associated with mixed dominants enhances resilience to variable disturbance regimes, and that below certain thresholds of abundance of each dominant, this resilience declines. Conservation management of Themeda–Poa ecosystems should thus aim to maintain an effective balance of these dominants. [ABSTRACT FROM AUTHOR]

The Metabolic Ecology Model predicts that tree diameter ( D) growth ( dD/dt) scales with D1/3. Using data on diameter growth and height–diameter relationships for 56 and 40 woody species, respectively, from forests throughout New Zealand, we tested one prediction and two assumptions of this model: (i) the exponent of the growth–diameter scaling relationship equals 1/3 and is invariant among species and growth forms, (ii) small and large individuals are invariant in their exponents and (iii) tree height scales with D2/3. We found virtually no support for any prediction or assumption: growth–diameter scaling exponents varied substantially among species and growth forms, correlated positively with species’ maximum height, and shifted significantly with increasing individual size. Tree height did not scale invariantly with diameter. Based on a quantitative test, violation of these assumptions alone could not explain the model's poor fit to our data, possibly reflecting multiple, unsound assumptions, as well as unaccounted-for variation that should be incorporated. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In three permanent inventory plots comprising 12.4 ha of undisturbed forest at La Selva, Costa Rica, all stems ≥10 cm dbh were mapped and identified to species. There were 1628, 1478 and 1954 trees in the plots, representing 168, 166 and 171 species respectively. We determined the species of each nearest-neighbor pair of trees, and asked whether the occurrence of species pairs conforms to a simple random mixing model. If trees are randomly mixed in terms of species, the expected frequency of any nearest neighbor species combination is a function of the relative abundance of the two species. Departures from random mixing could arise from species interactions, differential responses to habitat, or both. The number of possible ij species combinations increases approximately as the square of the number of species. For the 168 species in plot 1, for example, there are 14 196 possible combinations. We compared the expected frequency of each species combination in the three plots (42 736 combinations in all) with observed frequencies. Over 98% of the combinations had observed frequencies of zero and expected frequencies close to zero. A consequence of high diversity is low density of most individual species, and exceedingly low frequencies of the vast majority of species combinations. For each of the 805 combinations with observed frequencies >0, we used simulation to generate a distribution of expected frequencies. We used a t-test to compare the observed frequency with the mean of the simulated distribution for each combination. Only 40 combinations (0.09% of the possible species combinations in the plots) departed from expected frequencies; 39 combinations were more common, and one less common than expected. The overwhelming majority of nearest neighbor species combinations occur at frequencies predictable from their individual abundances. [ABSTRACT FROM AUTHOR]

1 Despite three decades of intensive research on seed predation, rather little is known about how important a role it plays in plant demography. Here a balance sheet of seed predation is drawn up for Pinus sylvestris, based on mortality caused by its main seed predators. This species is of special interest because trees carry seeds throughout the year and can therefore support specialist as well as generalist seed predators. Also, its regeneration in Scotland is weak and some of its main seed predators (red squirrels, crossbills, wood ants) are themselves threatened. 2 Field data from two P. sylvestris forests were used to estimate rates of predation on seeds due to pre- and post-dispersal predators, including both specialists and generalists. The rates of predation changed systematically over time and were fitted to time-dependent functions. The resulting functions were incorporated into a model, which was solved numerically to determine the fate of a cohort of seeds. 3 On average, approximately 20% of seeds in the cohort were consumed by pre-dispersal seed predators, approximately 25% of seeds by post-dispersal seed predators, and approximately 55% of seeds were still alive at the end of 2 years. This reduces the seed pool for regeneration of P. sylvestris, but is unlikely to be a serious problem for regeneration. 4 Seed survival was most sensitive to the rate at which seeds became invulnerable to further seed predation, and to the rate of seed dispersal from cones on trees. Seed survival was less sensitive to seed predation. However, among seed predators, carabids feeding on loose seeds and birds eating seeds in open cones were the most important. 5 Cones open as they dry out, and the timing of seed dispersal is therefore weather-dependent. Late opening of cones had a deleterious effect on seed survival because it led to an increase in pre-dispersal seed predation. Thus, in a period of climate change, patterns of seed predation would be expected also to change, altering the success of regeneration. [ABSTRACT FROM AUTHOR]

1 This review brings into focus what is known about the response of the herbaceous layer of forest ecosystems to increasing nitrogen deposition. The emphasis on forests in general is important for two reasons. First, forests often occupy areas receiving high rates of atmospheric deposition of N. Second, compared with herb-dominated communities, about which much is known regarding response to excess N, forests generally display greater biological and structural complexity. The more specific focus on the herbaceous layer – here defined as all vascular (herbaceous and woody) plants ≤ 1 m in height – is warranted because most of the species diversity of forests occurs in the herb layer. 2 Most responses of forest ecosystems to N saturation, defined here as ecosystem supply of N exceeding ecosystem demand for N, can be characterized by two complementary hypotheses, each emphasizing different facets of ecosystem structure and function. One focuses on ecosystem processes, such as net primary productivity, whereas the other addresses seasonal patterns of concentrations of in stream water. Although neither hypothesis considers the effects of chronically elevated N deposition on forest herbs, both share a prediction – a dramatic increase in availability of – that is relevant to forest herb response. Such a shift towards dominance has important implications for changes in herbaceous layer dynamics. For example, increases in soil pools can increase invasibility by exotic species. Also, because preferential use of vs. can be highly species-specific among forest herbs, predominance of availability can bring about further changes in herb layer species composition. Also important to forest herbs is the tendency for enhanced mobility of to increase mobility and decrease availability of essential cations, such as Ca2+. 3 The response of plant species of the herbaceous layer of forest ecosystems to excess N availability can arise from N-mediated changes in several processes. Here I identify six – competition, herbivory, mycorrhizal infection, disease, species invasions and exotic earthworm activity – and discuss how they respond to excess N and how this response affects the herb layer of forests. With the exception of the activity of exotic earthworms (which is correlated with, but not necessarily caused by, high N deposition), there is compelling evidence that all processes respond sensitively to N deposition and that this response generally leads to drastic shifts in species composition and decreases in biodiversity of forest herb communities. 4 A hypothesis is suggested – the nitrogen homogeneity hypothesis – that predicts loss of biodiversity in forest ecosystems experiencing chronically elevated N deposition. This hypothesis is based on the decrease in spatial heterogeneity of N availability that is typically high in forest soils under N-limited conditions. [ABSTRACT FROM AUTHOR]

Aim This study used data from temperate forest communities to assess: (1) five different stepwise selection methods with generalized additive models, (2) the effect of weighting absences to ensure a prevalence of 0.5, (3) the effect of limiting absences beyond the environmental envelope defined by presences, (4) four different methods for incorporating spatial autocorrelation, and (5) the effect of integrating an interaction factor defined by a regression tree on the residuals of an initial environmental model. Location State of Vaud, western Switzerland. Methods Generalized additive models (GAMs) were fitted using the grasp package (generalized regression analysis and spatial predictions, http://www.cscf.ch/grasp). Results Model selection based on cross-validation appeared to be the best compromise between model stability and performance (parsimony) among the five methods tested. Weighting absences returned models that perform better than models fitted with the original sample prevalence. This appeared to be mainly due to the impact of very low prevalence values on evaluation statistics. Removing zeroes beyond the range of presences on main environmental gradients changed the set of selected predictors, and potentially their response curve shape. Moreover, removing zeroes slightly improved model performance and stability when compared with the baseline model on the same data set. Incorporating a spatial trend predictor improved model performance and stability significantly. Even better models were obtained when including local spatial autocorrelation. A novel approach to include interactions proved to be an efficient way to account for interactions between all predictors at once. Main conclusions Models and spatial predictions of 18 forest communities were significantly improved by using either: (1) cross-validation as a model selection method, (2) weighted absences, (3) limited absences, (4) predictors accounting for spatial autocorrelation, or (5) a factor variable accounting for interactions between all predictors. The final choice of model strategy should depend on the nature of the available data and the specific study aims. Statistical evaluation is useful in searching for the best modelling practice. However, one should not neglect to consider the shapes and interpretability of response curves, as well as the resulting spatial predictions in the final assessment. [ABSTRACT FROM AUTHOR]

Aim We analyse regional patterns of woody plant species richness collected from field data in relation to modelled gross photosynthesis, Pg, compare the performance of Pg in relation to other productivity surrogates, and examine the effect of increasing scale on the productivity–richness relationship. Location The forested areas in the north-western states of Oregon, Washington, Idaho, and Montana, USA. Methods Data on shrub and tree species richness were assembled from federal vegetation surveys and compared with modelled growing season gross photosynthesis, Pg (the sum of above- and below-ground production plus autotrophic respiration) and two measures of spatial heterogeneity. We analysed the productivity–richness relationship at different scales by changing the focus size through spatial aggregation of field plots using 100 and 1000 km2 windows covering the study area. Regression residuals were plotted spatially. Using the best available tree data set (Continuous Vegetation Survey: CVS), we compared different productivity indices, such as actual evapotranspiration and average temperature, in their ability to predict patterns of tree species richness. Results The highest species richness (species/unit area) occurred at intermediate levels of productivity. After accounting for variable sampling intensity, the richness–productivity relationship improved as more field plots were aggregated. At coarser levels of aggregation, modelled productivity accounted for 57–71% of the variation in richness patterns for shrubs and trees (CVS data set). Measures of spatial heterogeneity accounted for more variation in richness patterns aggregated by 100 km2 windows than aggregation by 1000 km2 windows. Pg was a better predictor of tree richness in Oregon and Washington (CVS data set) than any surrogate productivity index. Main conclusions Pg was observed to be a strong unimodal predictor of both tree (CVS) and shrub (FIA) richness when field data were aggregated. For the tree data set examined, seasonally integrated estimates of photosynthesis (Pg) predicted tree richness patterns better than climatic indices did. [ABSTRACT FROM AUTHOR]

We describe extraordinary aspects of the feeding ecology of the austral parakeet, Enicognathus ferrugineus – the most southerly distributed psittacid in the world – that allow this endemic species to inhabit and become a common bird in relatively species-poor temperate and subantarctic Nothofagus forests of South America. We used two sources of information to analyse temporal and spatial dietary changes of austral parakeets in subalpine forests near Lake Distric of southern Argentina: (i) relative abundance of parakeet foraging on the forest floor along an altitudinal transect from 1000 to 1420 m; and (ii) faeces analyses of seasonal collections. Austral parakeets largely relied on a protein-rich pollen-based spring – early summer diet by destructively harvesting large quantities of wind-pollinated Nothofagus pumilioflowers and efficiently emptying pollen grains – specializations previously described only in pollinating nectarivorous vertebrates. Pollen emptying rates ( c. 65%) were the highest reported for psittacids and among the highest for vertebrates in general. Parakeets made extended use of short-lived N. pumilioflowers by tracking the altitudinal shifts in flowering phenology. Additionally, parakeets complemented their diet with carbohydrates from N. pumilio insect exudates. By late summer, parakeets switched to a lipid-rich diet based on N. pumilio seeds. This resource remained available through mid-autumn because parakeets also followed in altitude the phenological delays in fruiting. In winter, parakeets fed on N. pumilio parasitic Misodendrum mistletoe buds and leaves and Cyttaria sp. parasitic canopy fungi. These results suggest that stringent food availability in these relatively high latitudes may have led to behavioural and physiological specializations of austral parakeets to obtain year-round food resources efficiently from Nothofagus trees. [ABSTRACT FROM AUTHOR]

Aim We developed an ecosystem classification within a 110,000-ha Arizona Pinus ponderosa P. & C. Lawson (ponderosa pine) landscape to support ecological restoration of these forests. Specific objectives included identifying key environmental variables constraining ecosystem distribution and comparing plant species composition, richness and tree growth among ecosystems. Location The Coconino National Forest and the Northern Arizona University Centennial Forest, in northern Arizona, USA. Methods We sampled geomorphology, soils and vegetation on 66 0.05-ha plots in open stands containing trees of pre-settlement ( c. 1875) origin, and on 26 plots in dense post-settlement stands. Using cluster analysis and ordination of vegetation and environment matrices, we classified plots into ecosystem types internally similar in environmental and vegetational characteristics. Results We identified 10 ecosystem types, ranging from dry, black cinders/ Phacelia ecosystems to moist aspen/ Lathyrus ecosystems. Texture, organic carbon and other soil properties reflecting the effects of parent materials structured ecosystem distribution across the landscape, and geomorphology was locally important. Plant species composition was ecosystem-specific, with C3 Festuca arizonica Vasey (Arizona fescue), for instance, abundant in mesic basalt/ Festuca ecosystems. Mean P. ponderosa diameter increments ranged from 2.3–4.3 mm year−1 across ecosystems in stands of pre-settlement origin, and the ecosystem classification was robust in dense post-settlement stands. Main conclusions Several lines of evidence suggest that although species composition may have been altered since settlement, the same basic ecosystems occurred on this landscape in pre-settlement forests, providing reference information for ecological restoration. Red cinders/ Bahia ecosystems were rare historically and > 30% of their area has been burned by crown fires since 1950, indicating that priority could be given to restoring this ecosystem's remaining mapping units. Ecosystem classifications may be useful as data layers in gap analyses to identify restoration and conservation priorities. Ecosystem turnover occurs at broad extents on this landscape, and restoration must accordingly operate across large areas to encompass ecosystem diversity. By incorporating factors driving ecosystem composition, this ecosystem classification represents a framework for estimating spatial variation in ecological properties, such as species diversity, relevant to ecological restoration. [ABSTRACT FROM AUTHOR]

Copyright of Conservation Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)