Individuals Of Native Species Research Articles

The ecology and tree species of urban green areas within the municipality of Campestre, Minas Gerais

Urban green areas produce benefits such as reduced air pollution, climate mitigation, reduced wind action, less noise pollution, shelter for fauna, and increased water uptake from the soil as well as increased water infiltration to the soil. This work carried out a floristic survey related to its diverse and characterized habit and dispersion, and also related to the origin of the species existing in four public squares within the municipality of Campestre, Minas Gerais. Thus, the floristic and ecological aspects of trees and shrubs were surveyed in four urban green areas of the municipality. All arboreal and shrubby individuals were marked and identified. Each identified species was classified according to habit, dispersion, and origin. In total, 313 tree individuals, shrubs, and palm trees were registered and distributed among 73 species, (62 genera and 30 botanical families). When considering all squares, Shannon’s diversity was 3.72, and Pielou’s evenness coefficient was 0.87. Lower values of diversity and evenness were observed for each public square. There was greater richness and number of individuals of native species compared to exotic ones. The yellow ipe (Handroanthus serratifolius) was the only species present in all studied squares. Sassafras (Ocotea odorifera) and pau-brasil (Paubrasilia echinata) are endangered species and underrepresented. The most represented forms of dispersion were zoochory and anemochory.

Differential learning by native versus invasive predators to avoid distasteful cleaning mutualists

Abstract Cleaning symbioses on coral reefs are mutually beneficial interactions between two individuals, in which a ‘cleaner’ removes and eats parasites from the surface of a ‘client’ fish. A suite of behavioural and morphological traits of cleaners signal cooperation with co‐evolved species, thus protecting the cleaner from being eaten by otherwise predatory clients. However, it is unclear whether cooperation between cleaners and predatory clients is innate or learned, and therefore whether an introduced predator might consume, cooperate with or alter the behaviour of cleaners. We explored the role of learning in cleaning symbioses by comparing the interactions of native cleaner fishes with both naïve and experienced, non‐native and native fish predators. In so doing, we tested the vulnerability of the predominant cleaners on Atlantic coral reefs, cleaning gobies (Elacatinus spp.), to the recent introduction of a generalist predator, the Indo‐Pacific red lionfish (Pterois volitans). Naïve juveniles of both invasive (P. volitans) and native predators (Cephalopholis spp. groupers) initially attacked cleaning gobies and hyperventilated from a putative toxin on the gobies' skin during laboratory experiments. After one to five such encounters, invasive lionfish often approached the cleaner closely, then turned away without striking. Consistent with learned avoidance, invasive lionfish rarely interacted with cleaning gobies in the wild, either antagonistically or cooperatively, and did not affect gobies' abundance. Native predators showed little evidence of learning during early encounters; they repeatedly attacked the cleaner during laboratory experiments and hyperventilated less violently than did lionfish. However, consistent with learned cooperation, native predators rarely antagonised and were frequently cleaned by gobies in the wild. We demonstrated that rapid, learned avoidance protects a distasteful cleaning mutualist from an invasive predator. The behavioural plasticity of this invader likely contributes to its success across its invaded range. Additionally, our results suggest that the cleaner's chemical defence most likely evolved as a way to deter predation and reinforce cooperation with naïve individuals of native species.

Impacts of plant invasions in native plant-pollinator networks.

The disruption of mutualisms by invasive species has consequences for biodiversity loss and ecosystem function. Although invasive plant effects on the pollination of individual native species has been the subject of much study, their impacts on entire plant-pollinator communities are less understood. Community-level studies on plant invasion have mainly focused on two fronts: understanding the mechanisms that mediate their integration; and their effects on plant-pollinator network structure. Here we briefly review current knowledge and propose a more unified framework for evaluating invasive species integration and their effects on plant-pollinator communities. We further outline gaps in our understanding and propose ways to advance knowledge in this field. Specifically, modeling approaches have so far yielded important predictions regarding the outcome and drivers of invasive species effects on plant communities. However, experimental studies that test these predictions in the field are lacking. We further emphasize the need to understand the link between invasive plant effects on pollination network structure and their consequences for native plant population dynamics (population growth). Integrating demographic studies with those on pollination networks is thus key in order to achieve a more predictive understanding of pollinator-mediated effects of invasive species on the persistence of native plant biodiversity.

Deconstructing compassionate conservation.

Compassionate conservation focuses on 4 tenets: first, do no harm; individuals matter; inclusivity of individual animals; and peaceful coexistence between humans and animals. Recently, compassionate conservation has been promoted as an alternative to conventional conservation philosophy. We believe examples presented by compassionate conservationists are deliberately or arbitrarily chosen to focus on mammals; inherently not compassionate; and offer ineffective conservation solutions. Compassionate conservation arbitrarily focuses on charismatic species, notably large predators and megaherbivores. The philosophy is not compassionate when it leaves invasive predators in the environment to cause harm to vastly more individuals of native species or uses the fear of harm by apex predators to terrorize mesopredators. Hindering the control of exotic species (megafauna, predators) in situ will not improve the conservation condition of the majority of biodiversity. The positions taken by so-called compassionate conservationists on particular species and on conservation actions could be extended to hinder other forms of conservation, including translocations, conservation fencing, and fertility control. Animal welfare is incredibly important to conservation, but ironically compassionate conservation does not offer the best welfare outcomes to animals and is often ineffective in achieving conservation goals. Consequently, compassionate conservation may threaten public and governmental support for conservation because of the limited understanding of conservation problems by the general public.

Annual mowing maintains plant diversity in threatened temperate grasslands

AbstractQuestionsDisturbance regimes shaped the evolution of grasslands but grazing exclusion and fire suppression have caused unprecedented increases in grassland biomass and biodiversity declines. Mowing reduces biomass but is not widely practiced in conservation reserves because of concerns about facilitating exotic plant invasion and altering ecosystem function. We asked whether regular mowing affected (1) the diversity of native and exotic functional groups, (2) spatial turnover in vegetation composition (β‐diversity), (3) vegetation attributes relating to biomass and structural heterogeneity, (4) community composition and (5) the distribution and abundance of individual native and exotic species.LocationFive temperate grassland reserves, south‐eastern Australia, encompassing C3 and C4 dominated communities.MethodsVegetation within reserves had been cut to 10 cm, once per year, for 10 years in late spring/early summer to maintain access tracks. We surveyed plant communities in mowed areas and nearby (<5 m) unmowed control areas (40 subplots per reserve, 200 total) and used linear mixed‐effects models to examine the effects of mowing.ResultsOf 24 functional groups, the richness of 16 native and exotic groups significantly increased with mowing. In 14 of these cases, effects were consistent across C3‐ and C4‐dominated grassland. Mowing reduced spatial turnover, but this did not reduce species richness at any spatial scale. When accounting for species abundance and evenness (Shannon diversity), effects of mowing were generally positive for native species and neutral for exotic species. Mowing increased native perennial grass cover and bare earth, decreased exotic perennial grass cover and litter, and changed community composition. Mowing reduced vegetation height but not structural heterogeneity. Mowing positively affected six individual native species and no exotic species. One native (Asperula conferta) and two exotic (Avena spp. and Nassella neesiana) species were found in lower abundance on mowed plots.ConclusionsAnnual mowing can be a useful conservation tool for threatened temperate grasslands but should be heterogeneous to ensure the persistence of mowing‐sensitive native species. Good vehicle hygiene is essential and localized complementary management (e.g., herbicide) might be required to reduce exotic forbs and grasses.

DENDROECOLOGIA DE <i>Sebastiania commniana</i> (Baill.) L.B.Sm. & Downs E<i> Hovenia dulcis</i> Thunb. EM UMA ÁREA DEGRersoADADA NA FLORESTA OMBRÓFILA MISTA ALUVIAL, SUL DO BRASIL

Em uma área da Floresta Ombrófila Mista Aluvial impactada por vazamento de óleo bruto no município de Araucária - PR, Brasil, conduziu-se o estudo dendroecológico de Sebastiania commersoniana (Baill.) L.B.Sm. & Downs (Euphorbiaceae) e da espécie exótica Hovenia dulcis Thunb. (Rhamnaceae). Os objetivos do estudo foram avaliar o efeito do alagamento da área a partir da construção de diques como medida de descontaminação de petróleo e de fatores meteorológicos no crescimento em diâmetro do tronco de ambas as espécies. Foram coletadas três séries temporais radiais do lenho de cada indivíduo adulto selecionado com uso de sondas de incremento, em duas condições, ambas com solo hidromórfico (Gleissolo Háplico), tendo como diferença a altura do lençol freático: SHT – saturação hídrica temporária (Sebastiania commersoniana n=12; Hovenia dulcis n= 10) e SHP – saturação hídrica permanente (Sebastiania commersoniana n=6; Hovenia dulcis n= 0). Séries cronológicas foram desenvolvidas, correlacionando-as com dados meteorológicos da região. Os resultados demonstraram que os indivíduos da espécie nativa em ambas as condições apresentaram padrão semelhante de crescimento, com tendência de diminuição ao longo dos anos; diferentemente dos indivíduos da espécie exótica, com tendência de aumento do incremento ao longo dos anos. Os indivíduos da condição SHP tiveram taxas menores de incremento após o ano do derramamento, o que mostra que o alagamento da área a partir da construção de diques como tentativa de descontaminação afetou o crescimento dos indivíduos. O crescimento das espécies correlacionou-se com a precipitação apenas na condição SHT. A temperatura mínima representou ser fator limitante ao crescimento de Sebastiania commersoniana, mostrando que temperaturas mais elevadas são importantes para o crescimento, principalmente no início do período deste. Entretanto, a ocorrência de temperaturas muito altas nos meses mais quentes pode ser limitante ao crescimento. Para Hovenia dulcis, nenhuma correlação significativa foi observada com a temperatura, porém, a precipitação mostrou-se fundamental nos meses em que a espécie mais cresce, sendo, no entanto, prejudicial em meses subsequentes às fortes chuvas devido ao efeito de saturação hídrica do solo.

Light Absorptive Properties of Articular Cartilage, ECM Molecules, Synovial Fluid, and Photoinitiators as Potential Barriers to Light-Initiated Polymer Scaffolding Procedures.

Many in vivo procedures to repair chondral defects use ultraviolet (UV)-photoinitiated in situ polymerization within the cartilage matrix. Chemical species that absorb UV light might reduce the effectiveness of these procedures by acting as light absorption barriers. This study evaluated whether any of the individual native biochemical components in cartilage and synovial fluid interfered with the absorption of light by common scaffolding photosensitizers. UV-visible spectroscopy was performed on each major component of cartilage in solution, on bovine synovial fluid, and on four photosensitizers, riboflavin, Irgacure 2959, quinine, and riboflavin-5'-phosphate. Molar extinction and absorption coefficients were calculated at wavelengths of maximum absorbance and 365 nm. Intact articular cartilage was also examined. The individual major biochemical components of cartilage, Irgacure 2959, and quinine did not exhibit a significant absorption at 365 nm. Riboflavin and riboflavin-5'-phosphate were more effectual light absorbers at 365 nm, compared with the individual native species. Intact cartilage absorbed a significantly greater amount of UV light in comparison with the native species. Our results indicate that none of the individual native species in cartilage will interfere with the absorption of UV light at 365 nm by these commonly used photoinitiators. Intact cartilage slices exhibited significant light absorption at 365 nm, while also having distinct absorbance peaks at wavelengths less than 300 nm. Determining the UV absorptive properties of the biomolecules native to articular cartilage and synovial fluid will aid in optimizing scaffolding procedures to ensure sufficient scaffold polymerization at a minimum UV intensity.

USING GENERAL AND SPECIFIC COMBINING ABILITY TO FURTHER ADVANCE STRAWBERRY (FRAGARIA SP.) BREEDING

Strawberry is one of the five fruit crops included in the USDA-funded multi-institutional and trans-disciplinary project, “RosBREED: Enabling Marker-Assisted Breeding in Rosaceae”. A Crop Reference Set (CRS) was developed of 900 genotypes and seedlings from 40 crosses representing the breadth of relevant diversity and encompassing founders used in breeding the domesticated strawberry. Individual native species and cultivar genotypes were included along with 10 progeny from 36 of the crosses of genotypes representing eastern and western North American and European short day and remontant cultivars. This CRS has been phenotyped in five U.S. states. Over 14 fruit quality traits have been studied, as well as remontancy, truss size, peduncle length, crop estimate, plant architecture, and disease resistance. The phenotyping conducted in the first growing season showed considerable variability amongst the genotypes and the locations for all of the characteristics. General and specific combining ability variance components were determined from the populations in order to provide breeders with guidance on the most effective breeding strategies for incorporating the superior traits from this germplasm into their programs.

Associations between a highly invasive species and native macrophytes differ across spatial scales

The association between invasive and native species varies across spatial scales and is affected by phylogenetic relatedness, but these issues have rarely been addressed in aquatic ecosystems. In this study, we used a non-native, highly invasive species of Poaceae (tropical signalgrass) to test the hypotheses that (i) tropical signalgrass success correlates negatively with success of most native species of macrophytes at fine spatial scales, but its success correlates positively or at random with natives at coarse spatial scales, and that (ii) tropical signalgrass is less associated with native species belonging to the family Poaceae than with species belonging to other families (Darwin’s naturalization hypothesis). We used a dataset obtained at fine (0.25 m2) and coarse (ca. 1,000 m2) scales. The presence/absence of all species was recorded at both scales, and their biomass was also measured at the fine scale. We tested the association between tropical signalgrass biomass and individual native species with logistic regressions at the fine scale, and using the T-score index between tropical signalgrass and each native species at both scales. The likelihood of the occurrence of six species (submersed and free-floating) was negatively affected by tropical signalgrass biomass at the fine scale. T-scores showed that three species were less associated with tropical signalgrass than expected by chance, but 22 species co-occurred more than expected by chance at the coarse scale. Associations between species of Poaceae and tropical signalgrass were null at the fine scale, but were positive or null at the coarse scale. In addition to showing that spatial scale affects the patterns of association among the non-native and individual native species, our results indicate that phylogeny did not explain associations between the invasive and native macrophytes, at both scales.

Experimental effect of consumer identity on the invasion success of a non-native cladoceran

An important goal of ecologists is to identify the characteristics of native communities that help to either promote or resist the invasion of non-native taxa. In this study, experimental mesocosms were used to determine how the richness and species identity of freshwater consumers influenced the invasion success of Daphnia lumholtzi (DL), a cladoceran that has successfully invaded aquatic habitats throughout the United States. Three species of native zooplankton were used to create a gradient of richness in replicated mesocosms that included all species in monoculture, all two species combinations, and all three species together. DL was then added to each mesocosm and its biomass was monitored over time. While additional research is needed to better determine how richness affects the invasion success of DL, the presence of native zooplankton resulted in reduced levels of DL biomass in all treatments relative to the zooplankton free controls. One species (Daphnia magna, DM) was able to reduce the biomass of DL to lower levels than the other two species. DL also appeared to be unable to establish or persist over time in mesocosms with DM, unlike in mesocosms with the two other species. These species–specific effects on invasion success appeared to be related to DM’s ability to reduce algal biomass to lower levels than the other two species. Therefore, while the presence of native zooplankton helps to reduce the biomass of DL once it is introduced into novel systems, the degree to which DL is able to establish and maintain populations over time within individual systems will likely depend on the presence or absence of particular species that can have particularly strong impacts on invasibility. Using such data, we may be able to predict which habitats are most likely to be invaded based on the presence or absence of individual native species.

Field‐based competitive impacts between invaders and natives at varying resource supply

Summary 1. One line of thinking is that highly successful plant invaders achieve dominance in recipient communities via competitive superiority over natives. In contrast, it has been proposed that exotic species attain dominance not by competitive prowess but due to their colonizing abilities after disturbance. Interestingly, there have been relatively few attempts to quantify competitive effects of invaders on natives (and vice versa ) in field settings. 2. We created monocultures of ten native perennial species and after two seasons of establishment we either left assemblages uninvaded or invaded them with seeds from one of three potent exotics; spotted knapweed ( Centaurea maculosa ), Dalmatian toadflax ( Lineria dalmatica ) and sulfur cinquefoil ( Potentilla recta ). Invasion was crossed with a supplemental water treatment to determine how increased resource supply might alter competitive outcomes. We also compared traits of exotics and natives to determine whether differences in height, lateral spread, shoot : root ratio and specific leaf area might shed light on competitive effects. 3. Exotics suppressed native biomass by an average of 51%. Water addition had no effect on invasibility or the competitive impact of exotics on natives. Although exotics decreased native biomass, invasion increased total above-ground biomass. Spotted knapweed was the most successful invader, and because of its greater abundance, it had the largest competitive impacts on natives. Spotted knapweed invasion also reduced plant-available soil nitrogen, water and light. 4. The majority of native species did not differ in their resistance to weed invasion, although Achillea millefolium and Festuca idahoensis monocultures were more resistant to invasion than monocultures of Antennaria rosea . Exotic biomass was either unaffected by competition with natives (knapweed) or was moderately suppressed by natives (cinquefoil and toadflax). Native species did not differ significantly in their competitive impacts on exotics and resource supply only influenced the competitive impacts of natives on spotted knapweed. Knapweed and toadflax, in particular, differed from all the natives in combined growth and leaf traits. 5. Synthesis . Our results show that exotics exert strong competitive dominance over individual native species with competitive effects relatively unaltered by increased resource supply. These effects occurred in undisturbed assemblages, suggesting that invader-native competitive outcomes can drive invasion dynamics for the species studied.

Guest Editorial: Rangelands, weeds and biodiversity

Australian rangelands are important for the diverse assemblages of native plants and animals that they support as well as for the wide variety of products and services that they provide. These assemblages are of national and international, cultural, social, ecological and economic significance. Woinarski (2001) identified several processes that are threatening the biodiversity of Australian rangelands, including grazing pressure, the proliferation of artificial watering points, vegetation clearing, predation by introduced animals and inappropriate fire regimes. His review also highlighted the importance of invasion by non-native plant species, a threatening process for ecosystems in other parts of Australia and around the world. Biological invasions pose a major risk for individual native species, communities and the ecological processes upon which they depend. The papers in this Special Issue of The Rangeland Journal consider non-native plant species in relation to the threats that they pose to the biodiversity of Australian rangelands and how those threats may be managed.