Native Vegetation Composition Research Articles

Keanekaragaman jenis tumbuhan invasif di Kawasan Hutan Sillu Kabupaten Kupang

Background: Invasive plants are plants that grow and spread to areas outside their original habitat. Invasive plants invade many forest areas, tourist attractions, and vegetation in Indonesia. Invasive plants can affect the composition of native vegetation so that it can threaten biodiversity in an area. The purpose of this study was to determine the diversity of invasive plant species in the Sillu Forest Area, Kupang Regency. Methods: The research method used is systematic sampling method with the placement of measuring plots is a plot line. Findings: The area studied was 70.24 Ha with the sampling intensity used was 5% and the number of measuring plots was 88 measuring plots. The vegetation analysis carried out was Density, Relative Density, Frequency, Relative Frequency, Important Value Index (INP) and Species Diversity Index. Conclusion: The results showed that there were 8 species from 5 families of invasive plants in the study site, namely krinyuh (Chromolaena odorata (L.) R.King & H. Rob), Ayam's Tahi Flower (L.). Rob, Bunga Tahi Ayam (Lantana camara L), Grinting grass (Cynodon dactylon), Jariji grass (Digitaria sanguinalis), Teki grass (Cyperus rotundus), Gala-gala (Amorpha fruticosa L), Ipomoea (Ipomoea indica (Burm.Merr) and Putri malu (Mimosa pundica L). The highest Index of Important Value is the type of Krinyuh (Chromolaena odorata (L.) R.King & H.Rob which is 62% while the lowest Index of Important Value is the type of Putri malu (Mimosa pundica L) which is 2%. The value of Diversity Index of invasive plants with 0.7683, which is included in the low diversity category.

Native and non‐native plant regrowth in the Santa Monica Mountains National Recreation Area after the 2018 Woolsey Fire

AbstractMediterranean‐type ecosystems are under chronic ecological stress. By assessing changes in plant species and functional groups across the landscape, identifying ecosystem degradation is possible. The Santa Monica Mountains are in close proximity to a densely populated urban area where non‐native species invasions are being driven by changing fire regimes, climate change, and anthropogenic disturbances. Non‐native growth impacts biodiversity levels and vegetation distributions of native plant communities that are critical for ecosystem health. This study uses analyses of line‐point data from the National Park Service Inventory and Monitoring Program to assess ecosystem health in the Santa Monica Mountains from 2014 to 2020 and, in particular, to assess the effects of the 2018 Woolsey Fire on the balance of native and non‐native species in the region. Results of this analysis show an increase in non‐native cover since 2014 and rapid regrowth of non‐native annual grasses and herbaceous cover after the 2018 Woolsey Fire while native communities regrew more slowly. A hotspot of non‐native cover was identified in the Northern Simi Hills region, and rapid regrowth was seen after the Woolsey Fire. The hotspot is dominated by non‐native annual grasses and annual herbaceous species, some of which returned to prefire populations within a year after the Woolsey Fire. These results raise concerns for the future of native vegetation composition and function throughout the park and highlight the damage densely populated non‐native plant communities accumulate in the wake of disturbance events.

Impacts of invasive alien species on riparian plant communities in South African savanna

Abstract Biological invasions are a threat to protected areas globally; however, the relative lack of studies quantifying the ecological impacts impairs informed decision-making. We selected three annual alien plants, widespread in the riparian habitats of the Kruger National Park, South Africa: Datura innoxia, Parthenium hysterophorus, and Xanthium strumarium, to examine their potential impacts on riparian plant communities. We identified 12–13 populations for each and placed a pair of invaded and uninvaded plots in each population. Species richness, Shannon diversity, and Pielou evenness were compared between the invaded and uninvaded plots using LMM models, and species composition was compared using ordination. The invaded vegetation showed lower species richness compared to the uninvaded, with the strongest effect observed for P. hysterophorus. The invaded plots also showed lower Shannon diversity and Pielou evenness due to the presence of alien dominants. For all three invaders, the invasion resulted in changes in the composition of native vegetation. Some native plants were more frequent and abundant in the invaded vegetation, possibly due to the habitats created in sandy river beds. The native species richness decreased with increasing invader cover, but the species richness of aliens accompanying the invasive dominants was not negatively affected by their cover. Our results confirmed the negative impact of invasive aliens on native plant diversity, with the most pronounced effect by Parthenium hysterophorus invasions.

Rock supplementation as an ecological restoration strategy for temperate grassland reptiles

AbstractTemperate grassland ecosystems support highly diverse assemblages of plants and animals but have been predominantly cleared for urban infrastructure and modified for agriculture. Temperate grasslands that remain in south‐eastern Australia are often degraded. For example, surface rocks have been extensively removed, potentially affecting long‐term persistence of grassland reptiles that depend on this resource. Rock habitat restoration is a strategy that can promote the survival of grassland reptiles and restore degraded temperate grasslands. In this study, we examined the benefit of supplementing locally sourced rock to improve reptile outcomes in degraded grassland reserves in the ACT. We established a BACI design across five ACT grassland reserves with 10 plots where rocks were added and 10 equivalent control plots to assess (i) the effect of rock supplementation on reptile relative abundance and composition, and (ii) the characteristics of the sites and rocks that reptiles used. Surveys were conducted over the spring and summer period each year over 3 years (2015–2017). Early results (one‐year post‐study) indicate that reptiles used supplemented rock and that reptiles show a preference for large (7600–29 000 cm3), flat rocks. Reptiles also show a preference for sites with higher grass cover and native vegetation composition, highlighting the need to manage site‐scale conditions to maximize the success of rock supplementation. Our study concludes rock restoration will support the persistence of grassland reptile populations, particularly if coupled with site‐scale grassland management, and will likely be an important strategy to use under changing climate regimes.

Differential Responses of Small Mammals to Woody Encroachment in a Semi-Arid Grassland

Encroachment by woody invasive plants is a major threat to grasslands and savannah ecosystems worldwide. Rodents, being primary consumers, are likely to be the first to respond to changes in the structure and composition of native vegetation. We examined the effect of an invasive shrub Prosopis juliflora (hereafter Prosopis) on the native rodent community of an arid grassland system of Western India. Our sampling plots were divided into five categories representing different stages of Prosopis invasion and other land cover types. These consisted of restored native grassland, agriculture fallow, open brushland, sparse-Prosopis plots, and Prosopis-dominated plots. We also examined the impact of woody invasion on the response of native rodents toward moonlight and temperature. As hypothesized, we found a significantly higher abundance of rodent species in the native grassland habitat compared to sparse-Prosopis habitats. However, there was no significant difference in rodent abundance and diversity between the grassland and Prosopis-dominated habitats. Thus, species richness and abundance of rodents were the highest in the restored grasslands and dense Prosopis thickets, and the lowest in the sparse Prosopis, potentially showing a “U” shaped response to Prosopis invasion. We observed a species-specific effect of Prosopis on the activity of Tatera indica, Bandicota bengalensis, and Millardia meltada. Habitat type mediated the effect of different environmental factors (moonlight and temperature) on the activity of the most commonly ocurring species T. indica while activity of M. meltada showed a weak association with environmental factors. B. bengalensis was the most generalist species showing similar activity across all habitat types. Thus, the impact of Prosopis invasion on the rodent community was uneven, and depended on species as well as on local environmental characteristics.

Impacts of Nicotiana glauca Graham Invasion on the Vegetation Composition and Soil: A Case Study of Taif, Western Saudi Arabia.

Invasive species are considered a serious problem in different ecosystems worldwide. They can compete and interfere with native plants, leading to a shift in community assembly and ecosystem function. The present study aimed to evaluate the effects of Nicotiana glauca Graham invasion on native vegetation composition and soil of the most invaded locations in the Taif region, Western Saudi Arabia, including Alwaht (WHT), Ar-Ruddaf (RDF), and Ash-shafa (SHFA). Plant species list, life span, life form, and chorotypes were assessed. Six locations highly infested with N. glauca shrubs were selected, and the morphological parameters of the shrubs were measured. Within each location, richness, evenness, relative density of species, and soil were measured either under the canopy of N. glauca shrubs or outside the canopy. Floristic analysis revealed the existence of 144 plant species, mainly perennial. The shrubs at the SHFA1 location showed the highest values of all measured morphological parameters. The WHT 1 location showed high richness and evenness, while the WHAT 2 location showed less richness and evenness. The invaded locations showed substantial variation in the community composition. Additionally, the effect of N. glauca on the understory species varied from competition to facilitation, where most of the understory species were inhibited. As an average of all locations, 65.86% of the plant species were recorded only outside the canopy of N. glauca. The vegetation analysis revealed that the SHFA location is more vulnerable to invasion that could be ascribed to its wide range of habitats and high disturbance. The soil–vegetation relationships showed significant variations among the studied locations regarding soil composition, and thereby showed a wide ecological range of the invasive shrubs N. glauca. Therefore, the invasion of N. glauca in the Taif region altered the species interactions, nutrients, and soil properties.

Ecosystem services of exclosures in Ethiopia: Review

Exclosures are areas that are closed-off from human and domestic animal disturbances to allow regenerating vegetation to reduce further land degradation and enhance rehabilitation. Exclosures have different ecosystem and economic benefits. The objectives of this systematic review were to appraise research findings and to summarize the most important literatures on the role of area exclosures for ecosystem services in Ethiopia. After several screening steps using inclusion and exclusion criteria, only 33 studies qualified for qualitative analysis. Different studies indicated that exclosures have ecological and economic importance for the area and local communities. The practice of area exclosures is becoming popular and about 7 Mha of the degraded area has been rehabilitated between the years 2011 and 2014. Moreover, a total of 15,404.6 ha of land have been established as area exclosure in different regions of the country from the year 2015-2019. A total of 1.4 Mha degraded lands were rehabilitated using area exclosures until 2019. Exclosures play vital role to restore native vegetation composition, richness, diversity, rehabilitation of degraded lands, reducing soil erosion, recharging ground water, increase soil and above ground biomass. In addition it provides considerable fodder access for livestocks and efficient to increase financial income for households.

Variations in soil properties and native woody plant species abundance under Prosopis juliflora invasion in Afar grazing lands, Ethiopia

IntroductionPastoralism and agro-pastoralism are the major modes of life in arid and semi-arid rangelands. However, rangeland quality and quantity are rapidly deteriorating due to a number of natural and human-induced factors, one of which is bush encroachment. Little is known on how bush encroachment affects the ecosystem functions and services expressed in terms of the native vegetation composition and structure, status of the soil seed bank, soil chemical and physical properties, and the abundance of mycorrhiza spores.MethodsWe assessed woody species in 64 plots distributed across four levels of Prosopis juliflora invasion (high, medium, low, and none) at two sites, Amibara and Gewane, in the Afar Region, Ethiopia. We collected composite soil samples to investigate the soil seed bank, mycorrhizal associations, and spore abundance.ResultsPlant biodiversity was generally low, with eight and four woody species in Gewane and Amibara, respectively. Prosopis juliflora was dominant in highly, moderately, and lowly invaded areas while Acacia senegal dominated the non-invaded areas. The average number of P. juliflora individuals ranged from 3/ha at non-invaded areas in Gewane to 4200/ha at highly invaded areas in Amibara while the total individual number of native woody species ranged from 0 to 88/ha at highly and lowly invaded areas, respectively. The population structure of trees/shrubs in all invasion areas showed an inverted J-shaped distribution, characterized by a high abundance of small individuals. Prosopis juliflora invasion was associated with high soil OC, Na, Ca, P, bulk density, and moisture content. Herbaceous seed numbers and species richness were highest in the moderately and highly invaded areas. All sampled tree species were associated with mycorrhiza but the percentage of root length colonization by different arbuscular mycorrhizal fungus structures varied significantly (p < 0.05) across invasion categories and sites.ConclusionsOur results revealed that although P. juliflora invasion negatively impacted the availability of native woody livestock forage species, it had a positive effect on most soil physical and chemical properties. Such variable effects call out for sustainable management practices when invaded areas are restored.

Neofityzacja łęgów jesionowo-wiązowych w dolinach polskich rzek = Neophyte-induced degradation of Poland’s riparian hardwood forests

Riparian hardwood forests have become very rare in most areas across Europe, as their fertile habitats have mostly been transformed into grasslands and arable land. Furthermore, where small patches remain, these are seen to be subject to major changes in soil cover and plant composition, thanks to habitat change induced by drainage, river engineering, the construction of river embankments and forestry. A further, highly visible symptom of the degradation of riparian hardwood forest is invasion by alien species (neophytes). This article therefore draws on work to analyze Poland’s vegetation of riparian hardwood forest, by reference to some 249 phytosociological relevés from 83 sites located along river valleys (Fig. 1). The work came within Natura 2000 habitat monitoring, and specifically a research project entitled Riparian hardwood forest services in the middle Vistula river valley. The main objectives here were to point to any relationships that might pertain between the share of invasive alien species and the structure and composition of riparian hardwood forest vegetation, as well as to determine the former’s habitat requirements. The studied communities were divided into two groups: ZI – with the presence of invasive alien species, and ZN – natural communities lacking such species (as listed by Tokarska-Guzik et al., 2012). Relationships between the share of invasive species and the structure and composition of native vegetation were tested by comparing species richness (number of species: S – general, SA – trees, SB – shrubs, SC – herbs, SD – bryophytes), species diversity (H – the Shannon diversity index (Shannon and Weaver, 1949), J – the Pielou evenness index (Pielou, 1975)), habitat preferences of species by reference to Ellenberg ecological indicators (Ellenberg et al., 1992) and socio-ecological affinity (after Schmidt et al., 2011). Spearman rank correlation coefficients were used to assess relationships between the numbers of invasive alien species and the cover-shares they accounted for on the one hand, and the values of all studied parameters on the other. Mean values were compared across the ZI and ZN groups using the Mann-Whitney U-test. Statistical analyses were performed using PAST 2.17 (Hammer et al., 2001). Invasive alien species were recorded on ca. 70% of the plots studied. Small balsam was species among the 15 observed most frequently and achieving greatest abundance (Table 1, Fig. 2). Lower general richness of species in the communities where invasive alien species are present results mainly from decline in numbers of hygrophilous and shade-tolerant forest species, as well as shrubs and bryophytes (Table 2). This may be related to changes in habitat conditions that diminish competition from the existing composition of the phytocoenosis. The undergrowth of communities featuring invasive species is composed of species preferring habitats with higher light availability, with a higher soil pH and a richer trophic status, but there are few species of more moist habitats. The broad habitat range characteristic for small balsam (as regards light and soil pH) combine with its preference for drier mesophilous sites and a marked capacity to disperse providing for the expansion of the species, which in fact comes to dominate in disturbed forest communities. On a more-positive note, the analysis shows how the degradation of riparian hardwood forests could be limited, if only their natural habitat conditions can be assured.

Native Vegetation Composition in Crested Wheatgrass in Northwestern Great Basin

Crested wheatgrass, an introduced perennial bunchgrass, has been seeded extensively on the rangelands of western North America. There is a perception that this species is very competitive and that it forms monoculture or low diversity stands where successfully seeded. However, there is limited information on species composition in sites previously seeded to crested wheatgrass. We measured native vegetation and environmental characteristics in areas seeded with crested wheatgrass across the northwestern Great Basin. Plant community composition within these crested wheatgrass stands was variable, from seedings that were near monocultures of crested wheatgrass to those that contained more diverse assemblages of native vegetation, especially shrubs. Environmental factors explained a range of functional group variability from 0% of annual grass density to 56% of large native bunchgrass density. Soil texture appeared to be an important environmental characteristic in explaining vegetation cover and density. Native vegetation was, for all functional groups, positively correlated with soils lower in sand content. Our results suggest environmental differences explain some of the variability of native vegetation in crested wheatgrass stands, and this information will be useful in assessing the potential for native vegetation to co-occupy sites seeded with crested wheatgrass. This research also suggests that crested wheatgrass seedings do not always remain in near monoculture vegetation states as seedings substantially varied in native vegetation composition and abundance with some seeded areas having a more diverse assemblage of native vegetation. In half the sites, there were five or more perennial herbaceous species and 63% of sites contained Wyoming big sagebrush. Although not exclusively true, species most commonly encountered in crested wheatgrass seedings are those that are able to minimize competition with crested wheatgrass via temporal (i.e., Sandberg bluegrass, annual forbs, annual grasses) or spatial (i.e., shrubs) differentiation in resource use.

Environmental consequences and the role of illegal waste dumps and their impact on land degradation

Landfilling is an anthropogenic activity that may causes land degradation and pollution. During the landfilling of waste, a wide range of pollutants can be released into the environment, e.g. landfill gases and leachate. The existence of illegal landfills is an increasing global problem. Illegal uncontrolled refuse storage areas, commonly referred to as "illegal waste dumps" (IWD), occur most frequently on forest margins, in ditches, on the peripheries of inhabited areas as well as at other places. IWD contaminate soils, pollute water, change vegetation, ecosystem functionality, and pose land degradation. It was hypothesized that IWD can disturb the species composition of native vegetation and create space for synanthropic as well as invasive plant species. These species may then spread from the IWD and affect the species composition of the natural ecosystems. The objective of this study was to search localities with the occurrence of IWD (within the Slovak Republic), to identify the types of waste, to assess the vegetation species composition, and based on the obtained results to determine the environmental impact. The monitored sites contained primarily municipal refuse and construction and demolition waste. The municipal refuse included plastic materials, glass and textiles. Tiles, pieces of concrete and insulation materials represented the construction and demolition waste. The results show that IWD represent specific habitats for plants. What is more, disturb the species composition of native vegetation and create space for the enforcement of synanthropic species as well as invasive plant species. The novelty of this work is that monitoring of vegetation can positively contribute to the evaluation of impacts of IWD on the environment. IWD should be removed and the concerned localities should be cleared, restored and reclaimed.

Municipal solid waste landfill – Vegetation succession in an area transformed by human impact

Landfilling is the most used and worldwide spread method of municipal solid waste (MSW) disposal. The disposal of MSW in landfills entails a number of environmental risks and raises concerns about harmful impacts on human health. The presence and number of contaminants should be monitored in each study assessing the impact of anthropogenic activities on the environment, which relate to MSW management. It was hypothesized that the landfill site can disturb the species composition of native vegetation and create space for synanthropic as well as invasive plant species. The aim of the present study is a long-term monitoring of plant community (floristic research) on an MSW landfill, identification of changes in the plant species composition on the landfill, and evaluation of the importance of the identified species for the surrounding ecosystem and for the safety of landfilling. The results demonstrate that MSW landfill creates a very specific environment. Our research shows that the species composition on the landfill is not stable and a place of specific plant succession. The vegetation on MSW landfills is not stable in terms of its species composition and therefore its continual monitoring is needed. This site has a high potential for invasive species, which may alter the species composition of the vegetation in surrounding ecosystems. Species problematic for agriculture were identified, too. It is necessary to pay attention to the species composition of landfill vegetation, possibly even control some species.

Approaches to urban vegetation management and the impacts on urban bird and bat assemblages

To balance the needs of people and biodiversity in cities, local governments are increasingly incorporating green spaces and urban greening initiatives into urban planning frameworks. Despite this, there is little information on which vegetation features or management actions are most useful in supporting biodiversity within these green spaces. We assess the effect of three vegetation management approaches that are commonly suggested to improve outcomes for urban biodiversity, including: (1) increasing the proportion of native vegetation; (2) increasing the density of trees, and (3) increasing the volume or complexity of understorey vegetation. We use a network of 39 urban green spaces (including golf courses, public parks and residential neighbourhoods) to assess how these vegetation management approaches impact urban bird and bat communities. The richness of both birds and bats increased with an increase in the proportion of native plants, bird species richness increased with increasing volume of understorey vegetation, and increasing large tree density led to increased bat activity. Our study suggests that increasing native vegetation composition and understorey vegetation volume, and the retention of large trees are practical vegetation management approaches that improve outcomes for urban birds and bats. Our data also suggests that as urbanisation and infill development proceeds, retention of large green spaces (such as golf courses) will be critical for urban biodiversity conservation, as these areas supported a component of the bird and bat fauna which was not recorded in other green space types.

Disturbance History, Management, and Seeding Year Precipitation Influences Vegetation Characteristics of Crested Wheatgrass Stands

Crested wheatgrass (Agropyron cristatum [L] Gaertm. and Agropyron desertorum [Fisch.] Schult.) has been seeded across millions of hectares of the sagebrush steppe and is often associated with native species displacement and low biological diversity. However, native vegetation composition of these seedings can be variable. To gain better understanding of the correlation between vegetation characteristics of crested wheatgrass seedings and their seeding history and management, we evaluated 121 crested wheatgrass seedings across a 54 230-km2 area in southeastern Oregon. Higher precipitation in the year following seeding of crested wheatgrass has long-term, negative effects on Wyoming big sagebrush (Artemisia tridentata Nutt. subsp. wyomingensis Beetle & Young) cover and density. Wyoming big sagebrush cover and density were positively correlated with age of seeding and time since fire. We also found that preseeding disturbance (burned, scarified, plowed, or herbicide) appears to have legacy effects on plant community characteristics. For example, herbicide-treated sites had significantly fewer shrubs than sites that were burned or scarified preseeding. Native vegetation cover and density were greater in grazed compared with ungrazed crested wheatgrass stands. The results of this study suggest a number of factors influence native vegetation cover and density within stands of seeded crested wheatgrass. Though disturbance history and precipitation following seeding can’t be modified, management actions may affect the cover and abundance of native vegetation in crested wheatgrass stands. Notably, grazing may reduce monoculture characteristics of crested wheatgrass stands and fire exclusion may promote sagebrush and perennial forbs.

Elevated carbon dioxide and fire reduce biomass of native grass species when grown in competition with invasive exotic grasses in a savanna experimental system

Invasive exotic grasses are known to increase fire severity and frequency in a number of fire prone systems. If elevated atmospheric carbon dioxide (CO2) increases growth rates and biomass production of these grasses, or increases their competitive ability, fire regimes may be further affected with detrimental consequences for native vegetation composition and diversity. Mesocosms containing three invasive exotic C4 grasses (Andropogon gayanus, Cenchrus polystachios, Cenchrus ciliaris), and three native C4 grasses (Heteropogon triticeus, Heteropogon contortus, Eriachne triseta), all from savanna woodlands of northern Australia, were grown as mixtures in field soil in glasshouses under elevated (700 ppm) and ambient (385 ppm) CO2, burnt and assessed for resprouting response. We found no effect of elevated CO2 on community biomass, however biomass of the invasive exotic grasses was much greater than that of native grasses at both CO2 concentrations. Species’ responses to elevated CO2 were varied. Two native grasses (H. triticeus and H. contortus) had significantly less biomass under elevated compared with ambient CO2 after burning, indicating an effect of elevated CO2 on resprouting response of these species when grown in competition. These results suggest that although overall productivity of this community may not change with increases in CO2 and fire frequency, community composition and species interactions in this fire-prone community may alter, shifting to a more exotic-dominated community and potentially resulting in an intensified fire frequency due to positive feedbacks.

Non-native plants and wildlife in the Intermountain West

Non-native plant invasions can change communities and ecosystems by altering the structure and composition of native vegetation. Changes in native plant communities caused by non-native plants can influence native wildlife species in diverse ways, but the outcomes and underlying mechanisms are poorly understood. Here, we review and synthesize current information for the Intermountain West of the United States, to develop a general mechanistic understanding of how invasions by non-native plants affect wildlife, and we identify important information gaps. In this region, most species of recognized conservation and management concern are non-native forbs (e.g., leafy spurge [Euphorbia esula], spotted knapweed [Centaurea stoebe]), although non-native grasses (e.g., cheatgrass [Bromus tectorum], medusahead [Taeniatherum caput-medusae]) also have greatly altered vegetation communities. These invasions by non-native plants affect native fauna through both trophic and non-trophic (habitat) pathways and via both direct and indirect effects. The degree to which these invasions affect wildlife depends largely on the degree to which non-native plants alter form and function of native vegetation communities. Reciprocally, native animals can influence distribution and abundance of non-native plants by facilitating or inhibiting invasions through herbivory, seed predation, seed dispersal, soil disturbance, and pollination. Current understanding of interactions between non-native plants and wildlife is limited because few invasions have been studied in sufficient detail to quantify population-level effects on wildlife reliably or to identify underlying mechanisms causing the observed effects. Although management of non-native plants has increased in this region, we understand even less about whether control measures can mitigate the adverse effects of non-native plants on organisms that occupy higher trophic levels. © 2013 The Wildlife Society.

Using habitat extent and composition to predict the occurrence of woodland birds in fragmented landscapes

The removal, alteration and fragmentation of habitat are key causes of biodiversity decline worldwide. In Australia, temperate woodlands have been disproportionately cleared following European settlement. Biodiversity decline in such systems may be reversed by restoration of native vegetation on agricultural land. However, rebuilding functioning habitat will require understanding the determinants of species distributions in existing habitat. We used logistic regression of bird occurrence data from 240 sites across northern Victoria, to determine the probability of occurrence of 29 woodland-dependent bird species. We modelled occurrence as a function of habitat variables that characterise both the extent (amount) and composition of native vegetation surrounding sites. Our specific goal was to determine whether the predictive performance of models is improved by accounting for both extent and composition of native vegetation compared with models that characterise native vegetation by extent alone. For nearly all species, accounting for vegetation composition in addition to extent and weighting habitat variables by distance improved the explanatory power of models, explaining on average 5.4 % (range 0–27.6 %) of the residual uncertainty in models that accounted for extent alone. Models that incorporate variation in vegetation composition can not only provide more accurate predictions of species occurrence, but also guide more appropriate restoration. They highlight the need for restoration to incorporate sites with fertile soils that support productive vegetation types. These models of woodland birds will be used to inform a spatially-explicit optimisation model for restoring native vegetation cover on agricultural land in this region, with the goal of achieving biodiversity gains while minimizing loss to production.

Both complete clearing and thinning of invasive trees lead to short‐term recovery of native riparian vegetation in theWesternCape,SouthAfrica

AbstractQuestionsMost rivers in theWesternCapeProvince ofSouthAfrica are heavily invaded by alien trees, often resulting in profound changes in biodiversity and ecosystem functioning. Although large‐scale management operations are underway to clear invasive trees and restore ecosystem function, little is known regarding native species recovery after alien clearing. HasEucalyptusinvasion along theBergRiver altered the distribution and composition of native vegetation? How does the removal of invasive trees through complete clearing and thinning facilitate the recovery of native vegetation?LocationBergRiver,WesternCape,SouthAfrica.MethodsWe assessed the recovery of native vegetation after 4 yr of complete clearing of the invasive treeEucalyptus camaldulensis(100% alien cover removal) and thinning (40–50% alien cover removal) along theBergRiver in theWesternCape,SouthAfrica. Native and alien plant cover, species richness and diversity were recorded on completely cleared and thinned sites and compared to natural (non‐invaded control sites) andE. camaldulensisinvaded sites.ResultsSpecies richness and diversity were significantly higher in both completely cleared and thinned sites compared to natural and invaded sites. Increases in species richness and diversity in completely cleared and thinned sites were a result of re‐invasion by alien herbaceous and graminoid species, which have the potential to hinder native species recovery. Cover of native trees and shrubs was higher in both completely cleared and thinned sites compared to invaded sites. Species composition (relative cover) in completely cleared and thinned sites was similar to species composition in natural sites.ConclusionsBoth complete clearing and thinning methods promote indigenous vegetation recovery and a positive trajectory towards recovery of ecosystem structure and composition can be expected in future. To improve management operations, a four‐stage thinning process that has the potential to facilitate native species recovery is suggested.

The application of a framework for assessing ecological condition and sustainability of use to three wetlands in Malawi

In Africa, the direct use of wetlands has long contributed to livelihoods, but use may lead to the degradation of wetlands. In order to better understand how the biophysical features of a wetland influence the sustainability of its use, an investigation was undertaken of the ecological condition and use of three wetlands in the Kasungu District, Malawi, where human pressures on wetlands are high. The first wetland, at the head of the catchment, had sandy soils and a gentle longitudinal slope, the second wetland, lower in the catchment, had clay soils and a steeper longitudinal slope, and the third wetland was intermediate. A framework was applied to score five functional components of ecological condition: hydrology, geomorphology, soil organic matter (SOM) accumulation, nutrient cycling and vegetation composition in terms of human impact, based on pre-defined field indicators. The framework highlighted particular vulnerabilities of individual wetlands in the face of human pressure. Vulnerability varied greatly across the wetlands in terms of: recovery of native vegetation composition following cultivation, geomorphic change through gully erosion and depletion of SOM. The framework is recommended for wider application in Africa as a means of highlighting the specific vulnerabilities of individual wetlands and for the improved focus of organizations which promote the ecologically sustainable use of wetlands.

Invasion of exotic plants in nutrient-enriched urban bushland

Abstract Invasion of exotic plants into vegetation communities on low-nutrient soils in Sydney is often attributed to increased phosphorus in the soil. However, the composition of native vegetation in nearby national parks has been found to be more closely correlated to combinations of soil nutrients and other environmental variables than phosphorus alone. This study examined whether phosphorus or a range of variables better matched patterns of native and exotic plants in urban bushland. Sites in urban bushland and national parks were sampled, vegetation frequency recorded and soil samples collected. Soil samples were analysed for a range of chemical and physical attributes. A significantly greater number of exotic species were found at the urban sites, and significantly fewer native species than in the national parks. All measured soil nutrients were found to be of a significantly increased concentration in urban soil. Using regression analysis, an index of all measured soil nutrients was found to explain more of the variation in the percentage of exotic species at a site than phosphorus alone. Multivariate analysis showed a gradient of sites from minimal exotic invasion to heavy invasion. However, this gradient also corresponded to changes in native species. The gradient was found to match that of increasing soil nutrient levels. A combination of soil nutrients was found to correlate better with the multivariate species composition than was phosphorus alone. The results suggest that it is the increase of many soil nutrients, not phosphorus alone, that is contributing to the invasion of urban bushland by exotic plants and the alteration of the suite of native species.