Germination biologies and seedbank dynamics of Acacia shrubs in the Western Desert: implications for fire season impacts on recruitment

2018 ◽  
Vol 66 (3) ◽  
pp. 278 ◽  
Author(s):  
Boyd R. Wright ◽  
Peter J. Clarke
Keyword(s):  
Woody Plants ◽  
Arid Zone ◽  
Western Desert ◽  
Fire Season ◽  
Seed Deterioration ◽  
Different Seasons ◽  
Soil Temperatures ◽  
Ecological Mechanisms ◽  
Season Of Burn ◽  
Incubation Temperatures

In arid Australia, fires in different seasons often result in markedly different recruitment rates of woody plants, and this can have important and long-lasting impacts on post-fire community structure and composition. The current study investigated ecological mechanisms behind this effect in four widespread arid Acacia species: Acacia aptaneura, Maslin & J.E.Reid Acacia kempeana F.Muell., Acacia maitlandii F.Muell. and Acacia melleodora Pedley. Specifically, the study examined whether increased recruitment after summer compared with winter burning relates to (1) higher soil temperatures during summer fires having increased capacity to overcome dormancy of seeds with heat-stimulated germination; (2) warmer soil temperature conditions after summer fires providing more favourable incubation temperatures for germination; and/or (3) summer fires coinciding with seasonal fluxes in seedbank densities, which may occur in response to granivory and/or rapid rates of seed deterioration after dispersal. Results supported hypotheses (1) and (2), as germination of all species responded positively to heat shock and warmer incubation temperatures. Some support was also demonstrated for hypothesis (3), as seedbank densities were shown to fluctuate seasonally, most likely in response to strong granivory. This multi-species study provides insights into mechanisms behind enhanced shrub recruitment after arid zone summer fires; and reinforces the notion that season of burn can be a strong determinant of regeneration trajectories of woody plants after fire.

Environmental elements for revitalization of entomophages in theforest plantations of the arid zone

2019 ◽  
pp. 55-70
Author(s):  
И.Р. Грибуст
Keyword(s):  
Woody Plants ◽  
Arid Zone ◽  
Cumulative Effect ◽  
Vertical Gradient ◽  
Steppe Zone ◽  
Maximum Effect ◽  
Forest Belt ◽  
Scientific Center ◽  
Biotic Potential ◽  
Estimation Of Distribution

Введение. Лесомелиоративное обустройство территорий малолесных регионов коренным образом преобразует ранее пустынные пространства. Позитивные изменения влажностнотеплового, почвенного, гидрологического режимов, обогащение аборигенной дендрофлоры новыми видами влечет за собой также и трансформацию животного мира, в том числе населения насекомых. Энтомосообщества формируются за счет представителей степной группы, обитателей естественных ценозов, а также группы лесных насекомых, в числе которых виды, являющиеся опасными вредителями и их энтомофаги. Цель работы анализ изменения разнообразия насекомыхэнтомофагов в насаждениях засушливой зоны различных параметров и состояния. Объекты исследований насекомыеэнтомофаги, обитающие в энтомокомплексах защитных насаждениях различного дендрологического состава ФНЦ агроэкологии РАН на территории Волгоградской области (кадастр. 34:34:000000:122 34:08:000000:6). Материалы и методика. Сбор материала проводили в насаждениях различного хозяйственного значения. Объектами исследования являлись полезные насекомые. Отбор проб проводили посредством окашивания крон энтомологическим сачком, визуальным осмотром модельных ветвей и ручным сбором хищников и паразитированных видов филлофагов с последующим выведением имаго в лабораторных условиях. Результаты и обсуждение. В сообществе полезных насекомых защитных лесных насаждений сухостепной зоны зафиксирован 221 вид энтомофагов, относящихся к 7 отрядам и 32 семействам. Различия экологических условий, ассортимент древесных растений в каждой из посадок, характер и интенсивность негативного внешнего влияния определяют особенности фаунистического населения, в т. ч. энтомофагов. Оценка распределения количественного обилия паразитов и хищников показала, что в лесных полосах хищников в среднем в три раза больше паразитических насекомых. Отчетливо прослеживаются вариации изменения разнообразия энтомофагов в насаждениях разного класса жизнеспособности. Конструктивные особенности, флористическая обедненность и сформировавшийся микроклимат существенно ограничивает жизнедеятельность энтомофагов в малорядных (23 ряда) насаждениях, численность которых здесь снижается в среднем в 2,5 раза по сравнению с многорядными посадками. В вертикальном градиенте посадок по мощности накопления биотического потенциала полезных насекомых выделяется травянистый ярус, наличие которого в лесополосе обусловливает увеличение числа особей энтомофагов в сообществе в 1,32,7 раза. Наименьшую роль в накоплении полезной группы насекомых играет наличие развитого подлеска. Заключение. Наличие в насаждениях энтомофильных древесных растений и развитого травостоя важнейшие экологические факторы для накопления биотического потенциала энтомофагов. Максимальный эффект обеспечивает совокупное влияние определяющих экологоструктурных элементов в многорядных посадках. Introduction. Forest reclamation area developmentpoor regions is radically transforms the previously desolate space. Positive changes in moistureheat, soil, hydrological regimes, enrichment of native dendroflora with new species also entails the transformation of the animal world, including the insect population. Entomologiste formed by the representatives of the steppe group of the inhabitants of the natural coenoses, and the group of forest insects, including species that are dangerous pests and their entomophages. The purpose of the analysis of changes in the diversity of insect entomophages in the plantations of the arid zone of different parameters and conditions. The objects of research insectsentomophages living in entomocomplexes protective plantation of different dendrological composition of the Federal scientific center for Agroecology wounds on the territory of the Volgograd region (the cadaster number is 34:34:000000:122 34:08:000000:6). Materials and methods. Collection of material was carried out in plantations of various economic importance. The objects of study were useful insects. Samples were collected by hilling crowns entomological net, by visual inspection of the model branches and handcollection of predators and parasitism species of phyllophagous with subsequent excretion of adults in the laboratory. Results and discussion. 221 species of entomophages belonging to 7 groups and 32 families were recorded in the community of useful insects of protective forest plantations of the dry steppe zone. Differences in environmental conditions, the range of woody plants in each of the plantings, the nature and intensity of the negative external influence determine the characteristics of the faunal population, including entomophages The estimation of distribution of quantitative abundance of parasites and predators showed that in forest bands of predators on average three times more parasitic insects. Variations in the diversity of entomophages in plantings of different classes of viability are clearly observed. Design features, floristic depletion and formed microclimate significantly limits the life activity of entomophages in smallrow (23 rows) plantations, the number of which is reduced by an average of 2.5 times compared to multirow planting. In the vertical gradient of plantings on the power of accumulation of biotic potential of useful insects, a grassy tier is allocated, the presence of which in the forest belt causes an increase in the number of entomophages in the community by 1.32.7 times. The least role in the accumulation of a useful group of insects is played by the presence of developed undergrowth. Conclusion. The presence of entomophilic woody plants and developed herbage in the plantations are the most important environmental factors for the accumulation of the entomophage biotic potential. The maximum effect provides a cumulative effect of determining ecological and structural elements in multirow landings.

scholarly journals Vegetation responses to season of fire in an aseasonal, fire-prone fynbos shrubland

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3591 ◽  
Author(s):  
Tineke Kraaij ◽  
Richard M. Cowling ◽  
Brian W. van Wilgen ◽  
Diba R. Rikhotso ◽  
Mark Difford
Keyword(s):  
Floristic Composition ◽  
Fire Season ◽  
Summer Drought ◽  
Winter Rainfall ◽  
Recruitment Success ◽  
Floral Diversity ◽  
Four Seasons ◽  
Different Seasons ◽  
Varied Response ◽  
One Year

Season of fire has marked effects on floristic composition in fire-prone Mediterranean-climate shrublands. In these winter-rainfall systems, summer-autumn fires lead to optimal recruitment of overstorey proteoid shrubs (non-sprouting, slow-maturing, serotinous Proteaceae) which are important to the conservation of floral diversity. We explored whether fire season has similar effects on early establishment of five proteoid species in the eastern coastal part of the Cape Floral Kingdom (South Africa) where rainfall occurs year-round and where weather conducive to fire and the actual incidence of fire are largely aseasonal. We surveyed recruitment success (ratio of post-fire recruits to pre-fire parents) of proteoids after fires in different seasons. We also planted proteoid seeds into exclosures, designed to prevent predation by small mammals and birds, in cleared (intended to simulate fire) fynbos shrublands at different sites in each of four seasons and monitored their germination and survival to one year post-planting (hereafter termed ‘recruitment’). Factors (in decreasing order of importance) affecting recruitment success in the post-fire surveys were species, pre-fire parent density, post-fire age of the vegetation at the time of assessment, and fire season, whereas rainfall (for six months post-fire) and fire return interval (>7 years) had little effect. In the seed-planting experiment, germination occurred during the cooler months and mostly within two months of planting, except for summer-plantings, which took 2–3 months longer to germinate. Although recruitment success differed significantly among planting seasons, sites and species, significant interactions occurred among the experimental factors. In both the post-fire surveys and seed planting experiment, recruitment success in relation to fire- or planting season varied greatly within and among species and sites. Results of these two datasets were furthermore inconsistent, suggesting that proteoid recruitment responses are not related to the season of fire. Germination appeared less rainfall-dependent than in winter-rainfall shrublands, suggesting that summer drought-avoiding dormancy is limited and has less influence on variation in recruitment success among fire seasons. The varied response of proteoid recruitment to fire season (or its simulation) implies that burning does not have to be restricted to particular seasons in eastern coastal fynbos, affording more flexibility for fire management than in shrublands associated with winter rainfall.

Fundamental features of modern inflorescence morphology

Bothalia ◽  
1983 ◽  
Vol 14 (3/4) ◽  
pp. 917-922 ◽  
Author(s):  
F. Weberling
Keyword(s):  
Woody Plants ◽  
Tropical Regions ◽  
Terminal Flower ◽  
Inflorescence Morphology ◽  
Inflorescence Axis ◽  
Apical System ◽  
Different Seasons ◽  
Single Flower ◽  
Lateral Branches ◽  
The Individual

Great diversity is found in inflorescences of angiosperms. According to Troll this is due to the variation of two types only: the polytelic and the monotelic type. In the monotelic inflorescence, the apex of the inflorescence axis commonly ends with a terminal flower. This also applies to all the floral branches below the terminal flower. All of these branches, whether branched or not, proved to be homologous elements, and they are all referred to by the term ‘paracladia’ because these branches repeat the structure of the main axis of the flowering system. Accordingly, their ramifications are called paracladia of the 2nd to nth order. Since by the presence of the paracladia the number of flowers in the flowering system is increased, they may be called ‘enriching branches’. Consequently the whole area which produces the enriching branches may be designated as an ‘enriching field’. In the lower part of the flowering shoot this zone is commonly preceded by a ‘field of inhibition’ within which the development of paracladia is inhibited more or less abruptly. The same zonation can be recognized in the individual paracladia if these are not reduced in any way. In perennials, the axillary buds at the base of the whole stem do not develop within the same season, but will give rise to the innovation shoots at the beginning of the following season. Therefore this area has to be distinguished as a ‘field of innovation’. The polytelic type of inflorescence probably has been derived repeatedly from the monotelic during the evolution of angiosperms by reduction of the terminal flower and specialization of the paracladia of the monotelic system. The distal elements are reduced to single lateral flowers or lateral cymes (partial florescences) which constitute elements of an apical system composed of lateral flowers. Instead of ending in a single flower, the floral axis thus terminates in a multi-flowered so-called polytelic ‘florescence’. The lower lateral branches repeat the structure of the main stem by producing (indefinite) florescences themselves and therefore may be termedparacladia (of the polytelic system). As in monotelic inflorescences the area of paracladia — the ‘enriching field’ — can be preceded by a ‘field of inhibition’ and, in perennial plants, by a ‘field of innovation’.Though generally we may confirm that the inflorescences of all species investigated (about 20 000 from nearly all angiosperm families) proved to be variations of one of the two fundamental types, it sometimes needs morphological experience to apply Troll’s system to woody plants of tropical regions. Difficulties may derive from prolepsis and syllepsis of the innovation shoots, prolification of the inflorescence axis and, abundantly, by the deficiency of clearly marked limits between sprouts growing in different seasons. In each of such cases, however, the homologous flower-bearing-elements can be identified by comparing their positions within the whole system of ramification.

Resprouting and mortality of juvenile eucalypts in an Australian savanna: impacts of fire season and annual sorghum

2010 ◽  
Vol 58 (8) ◽  
pp. 619 ◽  
Author(s):  
Patricia A. Werner ◽  
Donald C. Franklin
Keyword(s):  
Dry Season ◽  
Fire Season ◽  
Annual Grass ◽  
Fire Behaviour ◽  
Wet Season ◽  
Low Intensity ◽  
Canopy Tree ◽  
Carbohydrate Storage ◽  
Savanna Fires ◽  
Different Seasons

In northern Australian savannas, canopy tree species often have juvenile tree banks that are composed mainly of small individuals of indeterminate age that have resprouted repeatedly after fire. Little is known about their demography. We report the initial responses (mortality, topkill and resprouting type) of 3133 marked juvenile eucalypts to set fires of different seasons (early dry season, late dry season, wet season, unburnt) in a 32 400 m2 field experiment. Fire treatments were repeated in plots dominated by a native annual grass (sorghum) that becomes senescent before the early dry season and provides the main fuel of savanna fires, and in others with little or no sorghum, but instead other native grasses and forbs that remain green well into the dry season. Most juvenile eucalypts <150 cm high were topkilled but resprouted from underground tissues regardless of fire season or understorey (86–100% vs <5% in unburnt plots). Few saplings 200–500 cm high died or were topkilled, but impacts of fire were harsher in sorghum than in non-sorghum vegetation. The response of eucalypts 150–199 cm high was intermediate, suggesting a ‘tactical’ transition from suppressed persistence to growth toward maturity. Counter-intuitively, genet death of juvenile trees was >22% in the low-intensity early dry season fire in plots with little or no annual sorghum, compared with <2% in all other fire/understorey combinations. We suggest results are related to fire behaviour, seasonal carbohydrate storage dynamics and competition with ground-layer plants.

The importance of environmental factors in soil fertility assessments. I. Dry matter production

1974 ◽  
Vol 25 (2) ◽  
pp. 299 ◽  
Author(s):  
RC Stefanson ◽  
N Collis-George
Keyword(s):  
Environmental Factors ◽  
Soil Fertility ◽  
Environmental Conditions ◽  
Culture Conditions ◽  
Light Regimes ◽  
Chemical Treatments ◽  
Different Seasons ◽  
Soil Temperatures ◽  
Growth Changes ◽  
Yield Responses

The importance of environmental factors on assessments of soil fertility was examined by means of pot experiments in the glasshouse. A preliminary experiment showed, over the course of 12 months of testing, that the fertility ratio varied with the season. In the main experiment each of two soils received nine chemical treatments in an omission-type experimental design. All chemical treatments were subjected to three different light regimes obtained by shading and to three soil temperatures. They were repeated at three different seasons of the year. Plants growing under acute mineral deficiency responded to changes in the environmental conditions and the deficiency became less acute the more the physical conditions favoured plant growth. Changes in environmental conditions were able to eliminate a marginal deficiency of plant nutrient. Because the results show many first and second order interactions between root temperature, light intensity and season, and because of the different yield responses to these factors for different soils and for different nutrients, an assessment of fertility by means of fertility ratios under one set of pot culture conditions cannot easily be applied to other situations.

scholarly journals Rainfall-Linked Megafires as Innate Fire Regime Elements in Arid Australian Spinifex (Triodia spp.) Grasslands

2021 ◽  
Vol 9 ◽  
Author(s):  
Boyd R. Wright ◽  
Boris Laffineur ◽  
Dominic Royé ◽  
Graeme Armstrong ◽  
Roderick J. Fensham
Keyword(s):  
Large Scale ◽  
Fire Regime ◽  
Climatic Factors ◽  
Arid Zone ◽  
Western Desert ◽  
Fuel Management ◽  
Fire Size ◽  
Weather Factors ◽  
High Rainfall ◽  
Patch Burning

Large, high-severity wildfires, or “megafires,” occur periodically in arid Australian spinifex (Triodia spp.) grasslands after high rainfall periods that trigger fuel accumulation. Proponents of the patch-burn mosaic (PBM) hypothesis suggest that these fires are unprecedented in the modern era and were formerly constrained by Aboriginal patch burning that kept landscape fuel levels low. This assumption deserves scrutiny, as evidence from fire-prone systems globally indicates that weather factors are the primary determinant behind megafire incidence, and that fuel management does not mitigate such fires during periods of climatic extreme. We reviewed explorer’s diaries, anthropologist’s reports, and remotely sensed data from the Australian Western Desert for evidence of large rainfall-linked fires during the pre-contact period when traditional Aboriginal patch burning was still being practiced. We used only observations that contained empiric estimates of fire sizes. Concurrently, we employed remote rainfall data and the Oceanic Niño Index to relate fire size to likely seasonal conditions at the time the observations were made. Numerous records were found of small fires during periods of average and below-average rainfall conditions, but no evidence of large-scale fires during these times. By contrast, there was strong evidence of large-scale wildfires during a high-rainfall period in the early 1870s, some of which are estimated to have burnt areas up to 700,000 ha. Our literature review also identified several Western Desert Aboriginal mythologies that refer to large-scale conflagrations. As oral traditions sometimes corroborate historic events, these myths may add further evidence that large fires are an inherent feature of spinifex grassland fire regimes. Overall, the results suggest that, contrary to predictions of the PBM hypothesis, traditional Aboriginal burning did not modulate spinifex fire size during periods of extreme-high arid zone rainfall. The mechanism behind this is that plant assemblages in seral spinifex vegetation comprise highly flammable non-spinifex tussock grasses that rapidly accumulate high fuel loads under favorable precipitation conditions. Our finding that fuel management does not prevent megafires under extreme conditions in arid Australia has parallels with the primacy of climatic factors as drivers of megafires in the forests of temperate Australia.

Distribution of Rabbit, Oryctolagus cuniculus, Warrens in relation to Soil Type

1985 ◽  
Vol 12 (3) ◽  
pp. 387 ◽  
Author(s):  
I Parer ◽  
JA Libke
Keyword(s):  
Soil Type ◽  
Oryctolagus Cuniculus ◽  
Arid Zone ◽  
New South ◽  
New South Wales ◽  
Deep Soil ◽  
Semiarid Environment ◽  
High Soil ◽  
South Wales ◽  
Soil Temperatures

Rabbit warrens in a semiarid environment of New South Wales were concentrated in those areas where impact penetrometer readings indicated friable soil to a depth of at least 75 cm. Isolated warrens in areas with few warrens were found in restricted patches of favourable soil. The absence of warrens from areas with shallow soil was considered to be due to high soil temperatures. The distribution of the rabbit in Australia was examined in relation to deep soil temperatures. It was suggested that the application of bituminous coating on ripped warrens may be a useful technique for the control of rabbits in the arid zone.

scholarly journals The scientific basis of enrichment of dendroflora of low-forest regions with economically valuable plants

2021 ◽  
pp. 35-51
Author(s):  
А.В. Семенютина ◽  
А.Ш. Хужахметова ◽  
А.А. Долгих ◽  
В.В. Сапронов
Keyword(s):  
Tree Species ◽  
Woody Plants ◽  
Arid Zone ◽  
Urban Ecosystems ◽  
Scientific Basis ◽  
Growth State ◽  
Lower Volga ◽  
Ash Trees ◽  
Trees And Shrubs ◽  
Selection Of

Вопросам адаптации, интродукции, селекции и семеноведения для подбора ассортимента древесных растений, используемых на деградированных землях в аридной зоне при обогащении дендрофлоры малолесных регионов, до настоящего времени уделялось мало внимания. В последние годы согласно нацпроектам «Наука» и «Экология» уделяется большое внимание адаптивной организации территории агро- и урбоэкосистем в целях повышения комфортности проживания населения и экологизации производства сельскохозяйственной продукции. Объекты – дендрологические искусственные насаждения, научно-производственные комплексы, питомники, ассортимент, адаптированный в засушливом поясе России (Нижневолжская станция по селекции древесных пород - филиал ФНЦ агроэкологии РАН; кад. №34:36:000014:178; Волгоградская обл.). Цель – обоснование и подбор адаптированных видов, форм деревьев и кустарников для обогащения дендрофлоры в агролесоводстве и озеленении в Нижнем Поволжье. Методология исследований построена на биоэкологических принципах интродукции, селекции и питомниководства на основе изучения растений в системе «генотип-среда», использовании эколого-хозяйственного потенциала древесных видов с учетом их изменчивости и специфики условий засушливого региона и обогащения дендрофлоры в лесомелиорации и озеленении. На маточных гибридных плантациях сосен, тополей, дубов, кленов и ясеней проведен учет роста, состояния, репродуктивного развития. Дано обоснование и методология биоэкологического подбора адаптированных видов, форм древесных растений в засушливых условиях. Представлен каталог ассортимента для питомниководства экономически важных адаптированных деревьев и кустарников. Получены материалы по выделенным таксонам для оформления объектов интеллектуальной собственности. Внедрение научных разработок проводилось на производственных питомниках Нижневолжской станции по селекции древесных пород. Ежегодная реализация сеянцев и саженцев на сумму около 7 млн. рублей из селекционного улучшенного семенного материала для обогащения дендрофлоры. Область применения: лесное хозяйство, озеленение, питомнические хозяйства, агролесомелиорация, природоохранные органы, образование. Until now, little attention has been paid to the issues of adaptation, introduction, selection and seed science for the selection of an assortment of woody plants used on degraded lands in the arid zone during the enrichment of dendroflora in sparsely forested regions. In recent years, according to the national projects "Science" and "Ecology", much attention has been paid to the adaptive organization of the territory of agro- and urban ecosystems in order to increase the comfort of living for the population and greening the production of agricultural products. Objects - dendrological artificial plantations, research and production complexes, nurseries, an assortment adapted in the arid belt of Russia (Lower Volga station for selection of tree species - branch of the Federal Research Center of Agroecology of the Russian Academy of Sciences; cad. No. 34: 36: 000014: 178; Volgograd region). The goal is to substantiate and select adapted species, forms of trees and shrubs for the enrichment of dendroflora in agroforestry and gardening in the Lower Volga region. The research methodology is based on the bioecological principles of introduction, selection and nursery based on the study of plants in the "genotype-environment" system, the use of the ecological and economic potential of tree species, taking into account their variability and the specific conditions of the arid region and the enrichment of dendroflora in forest reclamation and gardening. On the parent hybrid plantations of pines, poplars, oaks, maples and ash trees, the growth, state, and reproductive development were recorded. The substantiation and methodology of bioecological selection of adapted species and forms of woody plants in arid conditions are given. A catalog of assortment for nursery of economically adapted trees and shrubs is presented. Materials were obtained on the allocated taxa for registration of intellectual property objects. The introduction of scientific developments was carried out at the production nurseries of the Nizhnevolzhskaya station for the selection of tree species. Annual sale of seedlings and seedlings worth about 7 million rubles from the selection of improved seed material for the enrichment of dendroflora. Scope: forestry, landscaping, nursery farms, agroforestry, environmental authorities, education.

scholarly journals New partnerships for managing large desert landscapes: experiences from the Martu Living Deserts Project

2015 ◽  
Vol 37 (6) ◽  
pp. 571 ◽  
Author(s):  
Tony Jupp ◽  
James Fitzsimons ◽  
Ben Carr ◽  
Peter See
Keyword(s):  
Threatened Species ◽  
Arid Zone ◽  
Economic Benefits ◽  
Management Control ◽  
Environmental Benefits ◽  
Western Desert ◽  
Cultural Economic ◽  
Nature Conservancy ◽  
European Settlement ◽  
Returning To Work

Native fauna in Australia’s arid zone has declined significantly since European settlement; however, Martu country in the Western Desert of Western Australia retains a diversity of iconic and threatened species that were once more widespread. An innovative partnership between The Nature Conservancy, BHP Billiton and the Martu people (represented by Kanyirninpa Jukurrpa – KJ) is achieving positive social, cultural, economic and environmental outcomes, which builds on funding from the Australian Government for land management on Martu country. The partners support Martu people in fulfilling their desire to conserve the cultural and natural values of their 13.7 million ha native title determination area. Through KJ as the local delivery partner, Martu people are returning to work on country to clean and protect waterholes; improve fire management; control feral herbivores and predators; manage cultural heritage; and actively manage priority threatened species (such as the Greater Bilby and the Black-flanked Rock-wallaby). The project provides significant employment opportunities for Martu men and women in ranger teams working throughout their country. It is also generating measurable social, cultural and economic benefits for Martu people and environmental benefits for part of the most intact arid ecosystem anywhere on Earth.

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