Vegetative Fragments Research Articles

Seed removal patterns of pioneer trees in an agricultural landscape

The seeds of most tropical plants are dispersed by animals, many of which also act as seed predators. Shifts in animal community composition, such as those driven by the clearing of native vegetation, are therefore likely to drive changes in plant recruitment. We used manipulative experiments excluding ants, small rodents, and birds to quantify the relative impacts of these granivores on animal-dispersed pioneer trees (ADPT) in fragments of savanna vegetation and adjacent soy plantations in Brazil’s Cerrado. We found that ants were the main consumers of ADPT seeds, that the rates of seed removal varied with seed size, and that removal rates were higher in savanna fragments than in soy plantations. However, we also found significant interactions between habitat type, seed species, and the type of seed predator being excluded. Our results underscore how challenging it can be to predict the influence of human disturbances on the interactions between plant and animal communities. Because ants, rodents, and birds are Cerrado’s the main seed dispersers and granivores, seedling recruitment in Cerrado landscape mosaics will depend on how these distinct but related processes are each influenced by species-specific patterns of seed size and seed abundance.

Biologia reprodutiva e hábitos alimentares do rodóstomo (Hemigrammus bleheri) um peixe ornamental da Bacia do Médio Rio Negro, Estado do Amazonas, Brasil.

Esse estudo teve como objetivo descrever a biologia reprodutiva e os hábitos alimentares de Hemigrammus bleheri do médio Rio Negro, estado do Amazonas-Brasil, ao longo de um ciclo hidrológico. Para tanto, analisaram-se os estádios de maturação gonadal, tamanho de primeira maturação sexual (L50), fecundidade e perí­­odo reprodutivo de 260 indiví­­duos, assim como pesquisou-se o conteúdo estomacal e calculou-se do í­­ndice de repleção estomacal de 177 indiví­­duos. Os resultados obtidos demonstram que a espécie possui desova parcelada, com oócitos variando entre 0,06 e 0,66 mm de dií­¢metro e fecundidade entre 101 e 721 oócitos. O L50 foi estimado em 2,8 cm para fêmeas e 2,6 cm para machos. As fêmeas amadurecem com a subida do rio (dezembro a maio) e as desovas ocorrem em maior proporção no final da enchente (março a maio). A espécie é oní­­vora, consumindo grande parte dos alimentos de origem autóctone. A dieta básica mostrou variações sazonais em sua composição, pois observou-se que microcrustáceos são frequentes nos perí­­odos de enchente/cheia, e que algas filamentosas, quironomí­­deos e fragmentos vegetais são mais frequentes na vazante/seca. Alterações sazonais na atividade alimentar foram registradas provavelmente influenciadas pelo pulso de inundação. O grau de repleção estomacal foi maior na enchente/cheia e menor na vazante/seca.

Edge effect on the population structure and the reproductive success of two Bursera species

Antecedentes. Las condiciones ambientales en los bordes de los fragmentos de vegetación afectan las características del ciclo de vida de la biota nativa (efecto de borde). Evaluamos el efecto de borde en dos especies de Bursera , las cuales son representativas de la comunidad madura del bosque tropical caducifolio (BTC) en México.
 Hipótesis. Esperábamos una estructura poblacional que reflejara la afectación de la reproducción supervivencia y crecimiento en los bordes de los fragmentos de BTC.
 Especies en estudio. Bursera fagaroides, B. palmeri .
 Sitio de estudio y fechas. Querétaro (Qro.), Apaseo el Grande (Gto.), México. Trabajo de campo: mayo-septiembre 2012.
 Métodos. Dentro de cada uno de los nueve fragmentos de BTC, trazamos parcelas en dos condiciones ambientales contrastantes (de borde e interior), entre las que se comparó la densidad, estructura de la población y el éxito reproductivo de las dos especies de Bursera, así como estimadores de la radiación solar y la compactación del suelo.
 Resultados. La radiación solar y la compactación del suelo no fueron diferentes entre las condiciones ambientales. En ambas especies la densidad de individuos fue mayor en el borde, donde los individuos con tamaños medianos y grandes fueron predominantes. El potencial reproductivo de los individuos, así como la viabilidad y la germinación de sus semillas, fueron similares entre los ambientes de borde e interior.
 Conclusiones. La densidad y la estructura poblacional mostraron una variación congruente con mayores tasas de reclutamiento, crecimiento y supervivencia en el ambiente de borde, las cuales podrían haberse presentado en las condiciones iniciales de mayor incidencia de la radiación en los bordes. La similitud que se observa actualmente en la radiación solar entre el borde y el interior de los fragmentos, pudo ser el resultado de la recuperación rápida del dosel bajo condiciones de una incidencia de la luz más alta en los bordes.

Assessing the drivers shaping global patterns of urban vegetation landscape structure

Vegetation is one of the main resources involve in ecosystem functioning and providing ecosystem services in urban areas. Little is known on the landscape structure patterns of vegetation existing in urban areas at the global scale and the drivers of these patterns. We studied the landscape structure of one hundred cities around the globe, and their relation to demography (population), socioeconomic factors (GDP, Gini Index), climate factors (temperature and rain) and topographic characteristics (altitude, variation in altitude). The data revealed that the best descriptors of landscape structure were amount, fragmentation and spatial distribution of vegetation. Populated cities tend to have less, more fragmented, less connected vegetation with a centre of the city with low vegetation cover. Results also provided insights on the influence of socioeconomics at a global scale, as landscape structure was more fragmented in areas that are economically unequal and coming from emergent economies. This study shows the effects of the social system and climate on urban landscape patterns that gives useful insights for the distribution in the provision of ecosystem services in urban areas and therefore the maintenance of human well-being. This information can support local and global policy and planning which is committing our cities to provide accessible and inclusive green space for all urban inhabitants.

Biomassa e atividade microbiana do solo em diferentes sistemas de cultivo do cafeeiro

The work aimed to evaluate the influence of different coffee farming systems in soil microbial biomass and activity. The experimental design consisted in randomized blocks in split plot, with five repetitions. Two seasons were evaluated, the first in April and the second in July 2015. The treatments consisted of three coffee cultivation systems and two control areas: 1) Coffee intercropped with trees species and Urochloa cv. decumbens; 2) Coffee intercropped with Urochloa cv. decumbens; 3) Coffee in monoculture; 4) ground fallow and 5) native vegetation fragment. The soil microbial biomass and activity were assessed in soil samples collected at 0.0-0.10 m depth. The following variables were evaluated: microbial biomass carbon, basal respiration, metabolic quotient, microbial quotient and soil organic carbon. Litter accumulation (t ha-1) and soil moisture (kg kg-1) were also evaluated. The systems fragment of native vegetation, Coffee in consortium with tree species and U. cv. decumbens and Coffee intercropped with U. cv. decumbens favour soil microbial biomass and activity, regardless the sampling time.

Where to survey? Spatial biodiversity survey gap analysis: a multicriteria approach

The aim of this study was to quantify the relative effort for biodiversity surveys across the public forest estate in the south-west of Western Australia. We collated information on historical surveys into a metadatabase and recorded locations where surveys had been conducted in a spatial geodatabase. We then used multicriteria modelling to rank land conservation units on the basis of relative survey effort. The results indicated that the western, particularly the south-western, parts of the study area were relatively well surveyed while eastern parts were relatively poorly surveyed. This is likely to reflect greater habitat loss and fragmentation of vegetation on the eastern margins of the forest estate where it adjoins the extensively cleared Western Australian wheatbelt. There was also an emphasis on monitoring biodiversity in forest habitats closer to the main population centres of the south-west. The results of this analysis provide a basis for assessing future survey needs for the region, which should also consider: patterns of distribution in species richness; the extent, connectivity and conservation status of native vegetation; and the relative risks posed to biodiversity by infrastructure and industrial land uses. We discuss the potential limitations of the multicriteria modelling approach in the context of our study.

The new associations of sinanthropic vegetation of classes Artemisietea vulgaris and Galio-Urticetea in the Bashkortostan Republic

The most widespread types of vegetation of the urbanized territories are coenosis of synanthropic and, in narrower sense, ruderal plant species. Ruderal communities are developing on garbage and dumps (Reymers, 1991), but presently this term is used much more widely, and is applied also to vegetation in various habitats arising under man impact. For example, W. Holzner (1982) includes abandoned fields and fellings in this type. So, the concepts of synanthropic and ruderal vegetation are rather close now. Synanthropic and ruderal communities are mostly found in the urban locations. The study of synanthropic vegetation in the Republic of Bashkortostan was being conducted since 1980s (Ishbirdin, etc., 1988; Golovanov, Abramova, 2012, 2013 etc.). The given paper presents results of the long-term (2008–2015) research of vegetation of 5 towns (Sterlitamak, Salavat, Ishimbay, Meleuz, Kumertau) located in Cis-Urals. More than 1500 relevés of synanthropic vegetation which were accumulated in the database using TURBOVEG software (Hennekens, 1995), 71 complete relevés of communities, new to the studied area, are presented in this paper. Classification is carried out according to Braun-Blanquet method. The ecological conditions were assessed with use of average values of E. Landolt (1977) ecological scales and processed by IBIS software (Zverev, 2007). According to «Prodrome of plant associations of the Republic of Bashkortostan» (Yamalov et al., 2012), synanthropic vegetation includes 8 classes, 14 orders, 21 unions, 62 associations and 6 communities. New for this region are one union and 9 associations, 2 of which are firstly described in the Southern Urals, while the other 7 were previously known in other regions of Russia or Europe. New to Bashkortostan Republic and Russian Federation, are associations of 2 classes Artemisietea vulgaris and Galio-Urticetea. There are 5 associations (Tanaceto vulgaris–Artemisietum vulgaris, Artemisio vulgaris–Echinopsietum sphaerocephali, Melico transsilvanicae–Agropyretum repentis, Falcario vulgaris–Elytrigietum repentis, and new Convolvulo arvensis–Agropyretum pectinati confined to the driest habitats in steppe and southern part of forest-steppe zone of the Southern Urals) within the class Artemisietea vulgaris. Within the class Galio-Urticetea 4 associations (Geo urbani–Chelidonietum majoris, Calystegio sepium–Epilobietum hirsuti, Calystegio sepium–Eupatorietum cannabini and new Urtico dioicae–Rubetum caesii) were described. New syntaxa occur mainly in Sterlitamak and Kumertau. Sterlitamak is the second largest city of Bashkortostan with the diverse anthropogenic habitats. The town of Kumertau, located in the south part of forest-steppe zone, is rich by various fragments of natural vegetation from forests to steppes.

京津冀地区城市化对植被覆盖度及景观格局的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 京津冀地区城市化对植被覆盖度及景观格局的影响 DOI: 10.5846/stxb201608311779 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金重大项目（41590841）；全国生态环境十年变化（2000-2010年）遥感调查与评估项目（STSN-12-01）；环境保护部专项（2110203） Spatiotemporal pattern of vegetation cover and its relationship with urbanization in Beijing-Tianjin-Hebei megaregion from 2000 to 2010 Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:定量研究了2000-2010年，京津冀地区植被覆盖度及其景观格局的动态变化，揭示了城市化进程对植被景观的干扰过程及生态质量的影响。结果表明：（1）2000-2010年，城市化进程显著是京津冀城市群土地变化的一大特点，人工表面面积从2000年的1.79×104 km2增加至2.16×104 km2，增幅高达21.16%；（2）京津冀平均植被覆盖度呈增加趋势但不显著（P=0.46），存在明显的时空动态差异。在覆盖度结构上形成了以中低和中植被覆盖度为主导的格局；（3）从景观空间格局变化来看，中低、高覆盖度区域植被景观更加破碎，而低、中等覆盖度区域的植被面积增加，景观破碎度减小；尤其是低植被覆盖度为主的城市区域，景观格局变化幅度大，表现为绿地面积有所增加，景观破碎化程度降低，生态质量有所改善；（4）在整个研究区范围，城市化对区域植被覆盖度存在负面影响，表现为城市化程度与区域平均植被覆盖度存在负相关（P=0.08）；但是在低植被覆盖度的区域（主要为城市区域），城市化程度与植被覆盖面积呈显著正相关（P < 0.001），表明城市区域在城市化进程中植被覆盖面积有所提高，生态质量有所改善，与城市化过程中，日益重视城市绿地的建设有关。 Abstract:Accelerated urbanization and socio-economic development can cause a series of environmental problems, such as decreased ecological quality. Accurately and efficiently quantifying the effects of urbanization on vegetation is critical for understanding regional ecological conservation and achieving sustainable development. Previous studies have primarily focused on the spatiotemporal patterns of vegetation cover and its relationship with climatic factors. Here, we quantified the spatiotemporal patterns of vegetation cover from 2000 to 2010 in the Beijing-Tianjin-Hebei megaregion. We then analyzed the effects of urbanization on vegetation cover dynamics. We used MODIS data and Landsat TM data. We found that (1) during the study period, urban land expanded very rapidly in this megaregion. The area of built-up lands increased from 1.79×104 km2 in 2000 to 2.16×104 km2 in 2010, which is an increase of 21.16%. (2) There was a slight but insignificant (P= 0.45) increasing trend in vegetation coverage from 2000 to 2010. The region was dominated by low-medium and medium coverage vegetation. (3) There were similarities and differences in the spatiotemporal patterns among different types of vegetation with varied levels of vegetation density. For vegetation types with low to medium and high vegetation density, fragmentation of vegetation increased from 2000 to 2010. In contrast, for vegetation types with low and medium vegetation density, the landscape pattern became more aggregated rather than fragmented in regions covered with these types of vegetation. (4) The proportional cover of developed land and vegetation coverage showed negative correlations (P= 0.08). However, the proportional cover of developed land showed a significantly positive relationship with the proportion of area covered by vegetation types with low vegetation density (P < 0.001). 参考文献 相似文献 引证文献

Native seed for restoration: a discussion of key issues using examples from the flora of southern Australia

Land clearing across southern Australia since European settlement has fundamentally changed the amount and distribution of native vegetation; it has also substantially reduced genetic diversity in plant species throughout Australia, especially in agricultural regions. The most recent State of the Environment report indicates that Australian biodiversity continues to decline. Many approaches to restoration are used in Australia including re-establishing plant populations using tube stock or by direct seeding. Native seed for these projects is often assumed to be plentiful and available for the majority of species we wish to restore but these assumptions are rarely true. We also rely on a small number of species for the majority of restoration projects despite the vast number of species required to fully restore complex plant communities. The majority of seed for restoration is still primarily collected from native vegetation despite longstanding concerns regarding the sustainability of this practice and the globally recognised impacts of vegetation fragmentation on seed production and genetic diversity. Climate change is also expected to challenge seed production as temperatures rise and water availability becomes more limited; changes to current planting practices may also be required. Until now native seed collection has relied on market forces to build a strong and efficient industry sector, but in reality the Australian native seed market is primarily driven by Federal, State and Territory funding. In addition, unlike other seed-based agri-businesses native seed collection lacks national industry standards. A new approach is required to support development of the native seed collection and use sector into an innovative industry.

Applying ecological landscape concepts and metrics in urban landscape management

Os conceitos de Ecologia da Paisagem aplicados ao planejamento urbano podem favorecer a hierarquização dos fragmentos de vegetação, identificando os de maior importância segundo os modos de ocupação dos setores da cidade. Apresenta-se estudo de município em profunda transformação, em função da exploração de minério de ferro no Quadrilátero Ferrífero, Minas Gerais. A metodologia pressupôs: 1 - a classificação de imagens de satélite RapidEye e mapeamento de uso e cobertura do solo; 2 - aplicação de métricas de paisagem (área, perímetro, distância ao vizinho mais próximo, área central, índice de forma e NRVI); 3 - integração de métricas usando análise multicritério. Foram identificadas áreas propícias para políticas públicas que promovam a gestão da cobertura vegetal, considerando não apenas as áreas verdes institucionais, mas também as propriedades particulares, entendendo a cobertura vegetal como uma rede sistêmica.

Lead-related infective endocarditis: Factors influencing early and long-term survival in patients undergoing transvenous lead extraction

Lead-related infective endocarditis (LRIE) is a serious infectious disease with uncertain prognosis. The purpose of this study was to evaluate the factors that influence survival in patients with LRIE undergoing transvenous lead extraction (TLE). Clinical data obtained from 500 consecutive patients with LRIE undergoing TLE in the reference center in the years 2006 to 2015 were retrospectively analyzed. We evaluated the effect of demographic, clinical, and procedure-related factors on 30-day and long-term survival (mean 3-year follow-up). Analysis of 30-day survival after TLE revealed 19 deaths (3.8%), with long-term mortality (mean 3-year follow-up) of 29.3% (146 deaths). Multivariate analysis showed unfavorable effects of age (hazard ratio [HR] 1.056, 95% confidence interval [CI] 1.030-1.082); decreased left ventricular ejection fraction (HR 0.687, 95% CI 0.545-0.866); renal failure (HR 3.099, 95% CI 1.865-5.150); and presence of vegetation fragments remaining after TLE (HR 1.384, 95% CI 1.089-1.760). Log-rank test and Kaplan-Meier survival curves demonstrated statistically worse prognosis in patients with large vegetations (>2 cm) and with vegetation remnants. Better prognosis was associated with LRIE coexisting with generator pocket infection. Long-term mortality in LRIE patients is still high. Factors that influence negatively on prognosis include large cardiac vegetations and their remnants after TLE. Such vegetations develop most frequently in patients with decreased left ventricular ejection fraction and renal failure. Probably, early detection of LRIE would tend to limit the formation of large vegetations that invade the adjacent cardiac structures.

COMPOSITION OF MEDIUM AND LARGE MAMMALS IN FOREST RESERVE IN THE CERRADO OF BRAZIL CENTRAL

ABSTRACT Knowledge about fauna location and distribution is very important for animal biology understanding. Conservation Units are relevant to biodiversity when considering factors such as hunting, agricultural expansion and forest fires. The conservation of native vegetation fragments under more suitable management plans, recovery areas and surveys are essential to the mammals preservation. This study aimed to survey the mammals of medium and large size of the Brasilia National Forest Area 1. To carry out this study it was performed weekly rounds in search for direct and indirect mammals traces existing at forest reserve. It is reported the presence of 27 species in the study area. According to the IUCN Red List, four species are vulnerable to extinction: tapir (Tapirus terrestris), giant anteater (Myrmecophaga tridactyla), giant armadillo (Priodontes maximus) and oncilla (Leopardus guttulus). Two species were recorded nearly threatened species: maned wolf (Chrysocyon brachyurus) and pampas deer (Ozotocerus bezoarticus). Also according to the same list, 48% (n=13) of species are declining in population trend and 26% (n=7) for this data is unknown. Differences in the area were observed, with mammal species presence associated to Cerrado vegetation types and in distribution of records over the period.

Quantifying macrophyte colonisation strategies—A field experiment in a shallow lake (Lake Balaton, Hungary)

Life-history traits like dominance of certain reproductive modes (e.g. vegetative, specialized, unspecialized or sexual propagules) and overwintering strategies (evergreen or re-sprouting) determine the success and timing of the ability of aquatic plants to colonize new areas. In the present experiment the distribution of these reproductive modes was examined in-situ, where new gaps were experimentally formed and establishment of new vegetation observed on a monthly bases in ten plots. During a period of 126days, altogether 73% of all established plants (n=1822) colonized by rhizomatic growth and 11% by rooting of vegetative fragments. Myriophyllum spicatum was observed to use mostly fragment rooting (81%), while Potamogeton perfoliatus followed a more mixed strategy combining re-rooting fragments and rhizomatic growth (31% and 41%, respectively). Stuckenia pectinata also preferred colonisation by rhizomes (84%). No colonisation by specialized vegetative units (tubers or turions) was observed during the study period The importance of surrounding vegetation was shown by comparing colonisation on inner and marginal sections of the plots (30% vs.70%). Three different patterns of timing of peak colonisation intensities were observed, related to species’ life-history traits. While several experimental works have been done on the regeneration and colonisation abilities of different species under laboratory conditions, information on the in-situ application of the different strategies is scarce. Insights on the modes by which plants succeed in colonising gaps helps us understand how (re)establishment of aquatic vegetation might function in lake ecosystems recovering after eutrophication.

Caracterização da macrofauna edáfica em sistemas de produção de grãos no Sudoeste do Piauí

Resumo O objetivo deste trabalho foi caracterizar a macrofauna edáfica em sistemas de produção de grãos sob plantio direto e convencional no Sudoeste do Piauí, na região de Matopiba. Amostras de solo foram coletadas nas camadas de 0,0-0,1, 0,1-0,2 e 0,2-0,3 m, com serrapilheira, em áreas cultivadas predominantemente com milho e soja, sob preparo convencional e plantio direto, em solos com diferentes texturas. Remanescentes de vegetação nativa adjacentes foram amostrados como referência. A macrofauna edáfica nos diferentes sistemas de uso do solo foi identificada até o nível de famílias, as quais foram agrupadas de acordo com suas funções ecológicas. Os grupos mais abundantes nas áreas amostradas foram Isoptera, Hymenoptera e Coleoptera, este com o maior número de famílias. A análise de componentes principais revelou que os grupos funcionais geófago/bioturbador, fitófago/praga e predador/parasita estão associados a solos de textura argilo-siltosa; enquanto o grupo detritívoro/decompositor, a solos mais arenosos. Os sistemas de manejo do solo alteram a estrutura da comunidade de macroinvertebrados edáficos em relação à condição natural de Cerrado. O plantio direto proporciona maior abundância e riqueza de espécies que o preparo convencional, e minimiza o impacto de sistemas agrícolas sobre a biodiversidade da macrofauna edáfica.

Fragmentación forestal en la subcuenca del río Pilón: diagnóstico y prioridades

La subcuenca del río Pilón es importante por la captación de agua para la agricultura comercial y por la conservación de la riqueza biológica del estado de Nuevo León. Sin embargo, se desconoce la magnitud de la fragmentación de sus bosques y matorrales, y no se han identificado los fragmentos remanentes prioritarios para conservar. Por lo tanto, este estudio evalúa la fragmentación de sus comunidades vegetales usando el tamaño del fragmento y la relación entre el perímetro y el área del fragmento (P/A) como indicadores de tamaño y forma, así como la distancia al vecino más próximo y el índice de intersección y yuxtaposición como indicadores de conectividad. Estos se calcularon en mapas generados mediante interpretación de imágenes de satélite Landsat de 1974 y 2000 (clasificación supervisada y estratificada). Los resultados muestran cambios estadísticamente significativos en el tamaño y forma de los fragmentos de todas las comunidades evaluadas, así como en su conectividad. Las comunidades más afectadas por la fragmentación en su forma y tamaño son el bosque de oyamel y de encino, así como el huizachal, el matorral submontano y el bosque de pino. En su conectividad, la fragmentación afecta sobre todo a los matorrales tipo tamaulipeco, submontano y desértico, así como los huizachales. En este estudio se evalúan los fragmentos prioritarios a conservar, considerando sus funciones como zonas de amortiguamiento y de estabilización de laderas, mediante la aplicación de criterios en un sistema de información geográfica. Al respecto se recomienda conservar 347 fragmentos para amortiguamiento y 210 fragmentos para estabilización de laderas.

Land tenure and landscape change: a comparison of public-private lands in the southern High Plains

Long-term drought in the southern Great Plains increases the vulnerability of coupled human-environment systems at a variety of scales. Developing better understandings of the dynamics at regional scales will become increasingly important as long-established land-use regimes break down in the face of climate change, resource depletion, and evolving governance. To demonstrate differential vulnerability during drought periods, this study hypothesized that observed increases in woody vegetation in grasslands would vary across land-tenure regimes. We argue that differences in State Trust Land governance, in part, lead to differential land management practices that contribute to landscape change. The study area encompasses adjacent counties, Cimarron County in Oklahoma and Union County in New Mexico, with similar climate variability and agricultural economies. We analyzed National Land Cover Database (NLCD) land-cover maps from 1992 and 2011 to assess changes in landscape composition and structure between 1992 and 2011. During both years under consideration, each county in the study region, across various land-tenure regimes, was dominated by herbaceous vegetation. However, there were changes in both composition and structure across the whole study area, in particular losses of herbaceous vegetation and increases in woody vegetation. The greatest gains in woody vegetation occurred in State Trust Lands of Cimarron County. Overall, the data suggest a fragmentation of herbaceous vegetation and a coalescing of shrubland patches. Research about the influence of land tenure on land management decisions, specifically the role of State Trust Land leases in overgrazing, informs the broader context of drought management in the southern Great Plains. Recommendations include continued research to highlight the specific mechanisms of land-tenure governance that drive landscape change.

Dingoes at the Doorstep: Home Range Sizes and Activity Patterns of Dingoes and Other Wild Dogs around Urban Areas of North-Eastern Australia.

Simple summaryConflicts with dingoes and other wild dogs are becoming increasingly common in and around urban areas of Australia. A lack of basic information about wild dog movement ecology hampers efficient planning and allocation of resources to mitigate human–wild dog conflicts. We captured, collared and released 37 wild dogs in urban areas of north-eastern Australia to investigate their movement ecology. In general, wild dogs occupied small fragments of bushland within an urban matrix, were active at all times of the day, and lived within a few hundred meters of houses and humans at all times. We conclude that wild dog management strategies in urban areas should focus on the mitigation of impacts at the individual or group level, and not population-level reductions in numbers.Top-predators around the world are becoming increasingly intertwined with humans, sometimes causing conflict and increasing safety risks in urban areas. In Australia, dingoes and dingo × domestic dog hybrids are common in many urban areas, and pose a variety of human health and safety risks. However, data on urban dingo ecology is scant. We GPS-collared 37 dingoes in north-eastern Australia and continuously monitored them each 30 min for 11–394 days. Most dingoes were nocturnal, with an overall mean home range size of 17.47 km2. Overall mean daily distance travelled was 6.86 km/day. At all times dingoes were within 1000 m of houses and buildings. Home ranges appeared to be constrained to patches of suitable vegetation fragments within and around human habitation. These data can be used to reallocate dingo management effort towards mitigating actual conflicts between humans and dingoes in urban areas.

Disentangling the four demographic dimensions of species invasiveness

SummaryA definitive list of invasive species traits remains elusive, perhaps due to inconsistent ways of identifying invasive species. Invasive species are typically identified using one or more of four demographic criteria (local abundance, geographic range, environmental range, spread rate), referred to here as the demographic dimensions of invasiveness.In 112 studies comparing invasive and non‐invasive plant traits, all 15 combinations of the four demographic dimensions were used to identify invasive species; 22% of studies identified invasive species solely by high abundance, while 25% ignored abundance.We used demographic data of 340 alien herbs classified as invasive or non‐invasive in Victoria, Australia, to test whether the demographic dimensions are independent and which dimensions influence invasive species listing in practice.Species' abundances, spread rates and range sizes were independent. Relative abundance best explained the invasiveness classification. However, invasive and non‐invasive species each spanned the full range of each demographic dimension, indicating that no dimension clearly separates invasive from non‐invasive species.Graminoids with longer minimum residence times were more frequently classified as invasive, as were forbs occurring near edges of native vegetation fragments.Synthesis. Conflating multiple forms of invasiveness, by not distinguishing invasive species that are identified using different demographic criteria, may obscure traits possessed by particular subsets of invasive species. Traits promoting high abundance likely differ from those enabling fast spread and broad ranges. Examining traits linked with the four demographic dimensions of invasiveness will highlight species at risk of becoming dominant, spreading quickly or occupying large ranges.

Landscape structure influences urban vegetation vertical structure

Summary Vegetation vertical structure is important for biodiversity and ecosystem service provision. In cities, however, while variation in the spatial extent and distribution of vegetation has been widely investigated, vertical vegetation structure and its potential drivers have not. Understanding how vegetation vertical structure varies across cities and identifying the potential drivers of this variation will improve the management of urban vegetation for biodiversity and ecosystem services. We used light detection and ranging (LiDAR) data to quantify the vertical structure of vegetation across Brisbane, Australia, at 1‐km2 and 1‐ha spatial scales and investigated how this structure varied in response to biophysical, socioeconomic, urban form and landscape structure variables. Using model selection techniques, we found that landscape structure variables related to tree cover (tree cover extent and spatial configuration) best explained the vegetation vertical structure at both spatial scales. Biophysical and urban form variables were also important, but only in combination with landscape structure. Mean vegetation vertical complexity, foliage projective cover and canopy height at a site all decreased as the treed proportion of the surrounding urban landscape decreased. In general, these vertical structure variables also increased where patches of vegetation were clustered together spatially. Synthesis and applications. Using light detection and ranging (LiDAR) data and model selection techniques, we show that the extent and vertical structure of urban vegetation are not independent and that reduced extent and increased fragmentation of urban vegetation are associated with simplification of its vertical structure. If common, this relationship means that managing urban vegetation for biodiversity and ecosystem services should not focus solely on the amount of tree cover or green space present across cities, but also on identifying where interventions to improve vegetation vertical complexity are required. Our study provides important insights into where these locations may be in cities.

Invasion of novel habitats uncouples haplo-diplontic life cycles.

Baker's Law predicts uniparental reproduction will facilitate colonization success in novel habitats. While evidence supports this prediction among colonizing plants and animals, few studies have investigated shifts in reproductive mode in haplo-diplontic species in which both prolonged haploid and diploid stages separate meiosis and fertilization in time and space. Due to this separation, asexual reproduction can yield the dominance of one of the ploidy stages in colonizing populations. We tested for shifts in ploidy and reproductive mode across native and introduced populations of the red seaweed Gracilaria vermiculophylla. Native populations in the northwest Pacific Ocean were nearly always attached by holdfasts to hard substrata and, as is characteristic of the genus, haploid-diploid ratios were slightly diploid-biased. In contrast, along North American and European coastlines, introduced populations nearly always floated atop soft-sediment mudflats and were overwhelmingly dominated by diploid thalli without holdfasts. Introduced populations exhibited population genetic signals consistent with extensive vegetative fragmentation, while native populations did not. Thus, the ecological shift from attached to unattached thalli, ostensibly necessitated by the invasion of soft-sediment habitats, correlated with shifts from sexual to asexual reproduction and slight to strong diploid bias. We extend Baker's Law by predicting other colonizing haplo-diplontic species will show similar increases in asexuality that correlate with the dominance of one ploidy stage. Labile mating systems likely facilitate colonization success and subsequent range expansion, but for haplo-diplontic species, the long-term eco-evolutionary impacts will depend on which ploidy stage is lost and the degree to which asexual reproduction is canalized.