A critical evaluation of minimum area concepts

Socio-Ecological Effects on the Patterns of Non-native Plant Distributions on Hainan Island

Non-native plants spread to recipient areas via natural or human-mediated modes of dispersal, and, if the non-native species are invasive, introduction potentially causes impacts on native plants and local ecosystems as well as economic losses. Therefore, we studied the diversity and distributional patterns of non-native plant species diversity in the tropical island province of Hainan, China and its relationships with environmental and socioeconomic factors by generating a checklist of species and subsequently performing an analysis of phylogenetic diversity. To generate the checklist, we began with the available, relevant literature representing 19 administrative units of Hainan and determined the casual, naturalized, or invasive status of each species by conducting field surveys within 14 administrative units. We found that non-native plants of Hainan comprise 77 casual species, 42 naturalized species, and 63 invasive species. Moreover, we found that non-native plant species had diverse origins from North and South America, Africa, and Asia and that the most common species across administrative areas belong to the plant families Asteraceae and Fabaceae. Moreover, the numbers of non-native species distributed in the areas of Hainan bording the coast arer greater than those within interior areas of the province. Among the coastal areas, Haikou has the highest species richness and, simultaneously, the highest values for significantly, positively correlated predictor variables, population and GDP (R2 = 0.60, P < 0.01; R2 = 0.64, P < 0.01, respectively). In contrast, the landlocked administrative units of Tunchang and Ding’an have the smallest number of non-native species, while their populations are less than a quarter of that of Haikou and their GDP less than one tenth. Among natural environmental variables, we determined that the number of non-native species had the strongest correlation with the minimum temperature in the coldest month, which predicts a smaller number of non-native species. Additionally, non-native species are primarily distributed in urban and rural built-up areas and agricultural areas; areas that are dominated by human activities. Overall, our study provides a working checklist of the non-native plants of Hainan as well as a theoretical framework and reference for the control of invasive plants of the province.

Change in plant species composition on powerline corridor: a case study

Clear-cutting of powerline corridors (PLCs) adversely affects ecosystem function by fragmenting intact forests and supports biodiversity with the development of a structurally diverse vegetation. The study aimed to determine diversity and composition caused by clear-cutting and monitor change in species composition on the PLC passing through Research Forest of IUC Faculty of Forestry. Species composition was monitored in 10 permanent plots on the clear-cut area (over 3 years) paired on the forest edge (over 2 years) and forest interior (first year). Diversity, the cover of invasive plants, and life form traits of the sample plots were compared. Change in species composition with time was determined with redundancy analysis (RDA) for repeated measures using CANOCO 5. Open-site conditions caused by clear-cutting promoted the number of hemicryptophyte and therophyte life forms which resulted in a high species richness on the clear-cut area (167 species), followed by forest edge (117 species) and forest interior (60 species). However, species richness which showed a peak in the second year was decreased at the end of 3 years. Total cover of invasives was considerably higher on the clear-cut area (23%) compared with the forest (3.78%) and did not make a significant effect on forest interior species in narrow corridors. Clear-cutting combined with slash piling promoted the undesired vertical development of tree sprouts and Robinia pseudoacacia which shortened management rotation in a short period. However, sites dominated by shrubs such as Cistus creticus and Cistus salviifolius suppressed the development and invasion of undesirable trees.

How long is enough to detect terrestrial animals? Estimating the minimum trapping effort on camera traps

Camera traps is an important wildlife inventory tool for estimating species diversity at a site. Knowing what minimum trapping effort is needed to detect target species is also important to designing efficient studies, considering both the number of camera locations, and survey length. Here, we take advantage of a two-year camera trapping dataset from a small (24-ha) study plot in Gutianshan National Nature Reserve, eastern China to estimate the minimum trapping effort actually needed to sample the wildlife community. We also evaluated the relative value of adding new camera sites or running cameras for a longer period at one site. The full dataset includes 1727 independent photographs captured during 13,824 camera days, documenting 10 resident terrestrial species of birds and mammals. Our rarefaction analysis shows that a minimum of 931 camera days would be needed to detect the resident species sufficiently in the plot, and c. 8700 camera days to detect all 10 resident species. In terms of detecting a diversity of species, the optimal sampling period for one camera site was c. 40, or long enough to record about 20 independent photographs. Our analysis of evaluating the increasing number of additional camera sites shows that rotating cameras to new sites would be more efficient for measuring species richness than leaving cameras at fewer sites for a longer period.

Which models are appropriate for six subtropical forests: species-area and species-abundance models

The species-area relationship is one of the most important topic in the study of species diversity, conservation biology and landscape ecology. The species-area relationship curves describe the increase of species number with increasing area, and have been modeled by various equations. In this paper, we used detailed data from six 1-ha subtropical forest communities to fit three species-area relationship models. The coefficient of determination and F ratio of ANOVA showed all the three models fitted well to the species-area relationship data in the subtropical communities, with the logarithm model performing better than the other two models. We also used the three species-abundance distributions, namely the lognormal, logcauchy and logseries model, to fit them to the species-abundance data of six communities. In this case, the logcauchy model had the better fit based on the coefficient of determination. Our research reveals that the rare species always exist in the six communities, corroborating the neutral theory of Hubbell. Furthermore, we explained why all species-abundance figures appeared to be left-side truncated. This was due to subtropical forests have high diversity, and their large species number includes many rare species.

Review of monitoring and assessing ground vegetation biodiversity in national forest inventories

Ground vegetation (GV) is an important component from which many forest biodiversity indicators can be estimated. To formulate policies at European level, taking into account biodiversity, European National Forest Inventories (NFIs) are one of the most important sources of forest information. However, for monitoring GV, there are several definitions, data collection methods, and different possible indicators. Even though it must be considered that natural conditions in different countries form very different understory types, each one has its own cost-efficient monitoring design, and they can hardly be compared. Therefore, the development of general guidelines is a particularly complex issue. This paper is a review of data collection methods and consequently a selection of the best available methods for the set of indicators with an emphasis on GV sampling methodologies in NFIs. As a final result, recommendations on GV definitions and classifications, sampling methodologies, and indicators are formulated for NFIs. Different sampling areas are recommended for each life form (shrubs, herbs, etc.). Inventory cycles and sampling seasons (depending on the phonological stages) should be specially considered and evaluated in the results. The proposed indicators are based on composition at different levels of sampling intensity for each life form and on coverage measurements.

Community structure of Auchenorrhyncha (Homoptera) in montane rain forest in Vietnam

The adult Auchenorrhyncha community within the understorey of a montane tropical forest in Vietnam is described A total of 1132 specimens representing 223 morphospecies and 16 families was found in a 4300-sweep sample None of the species exceeded the 5% dominance level More than half the species are represented by single individuals within the 309 ms of vegetation Spatial community pattern is mosaic like at a scale of hundreds of metres as the similarity of 100 sweep samples does not depend on their spatial distance Areas 1 5–3 km distant from one another differ markedly in their Auchenorrhyncha communities These between-site differences exceed the intra-site community heterogeneity Population density of Auchenorrhyncha species is not correlated with their body size The Auchenorrhyncha community within a forest markedly differs from the community of an adjacent ruderal area A transitional zone between these habitats is intermediate in Auchenorrhyncha species composition

Plant species diversity in an old, traditionally managed hay meadow compared to abandoned hay meadows in southwest Norway

A chronosequence, representing a successional series, was used for the comparison of a hay meadow site managed in an old traditional way for at least a hundred years, and hay meadow sites abandoned for about 10, 20 and 30 years, respectively. Old traditional management included grazing early and late in the growing season, mowing in August and light or no fertilizing. The tree cover was the most important factor deciding the composition of vegetation. Time since abandonment was not completely correlated to tree cover, as some plots had a dense canopy and others were situated in the open. The total species number decreased with number of years since abandonment in plots > 0.001 m²and <100 m². The highest species number in 1 m² plots was recorded in the managed site, with 38 species of phanerogams. Fourtyeight % of the indicators of traditional management present in the managed site was recorded in the site which had been abandoned for 30 years. Frequency - log area curves made it possible to group species according to persistence in the sward. As a result, a group of functional indicators of rare hay meadows in the region was distinguished.

Integrated response plot designs for indicators of desertification

The improvement of land management practices on lands susceptible to desertification requires information on the status and condition of the existing resources as well as any change occurring in the resource condition over time. The Environmental Monitoring and Assessment Program (EMAP) of the U.S. Environmental Protection Agency has developed a statistical survey design for monitoring the condition of ecological resources on large spatial scales. EMAP-Rangelands used a uniformity sampling study in 1993 to evaluate response plot designs for three categories of indicators (soils, vegetation, and spectral reflectance) to be used for monitoring ecological condition of a site. The response plot design study was developed to integrate on-site measurements for the three indicator categories. The study was conducted on the Colorado Plateau in southern Utah in three rangeland resource classes (grassland, desertscrub, and conifer woodland) of differing productivity levels in an attempt to develop a common plot design for all three resource classes. Basic measurement units were developed to facilitate integration of data collection. Preliminary spatial analysis of the sampling study found considerable differences in variation patterns among the study sites and measurement categories for the indicator classes used by EMAP-Rangelands. Evidence of substantial trends in the indicator measurements on monitoring sites relative to regional trends leads to the conclusion that nonstationary spatial models for biological processes on a monitoring site may be needed to fulfill the requirements for developing plot designs and indicator criteria.