Introduction Of Predators Research Articles

Distribution and Abundance of Pine Needle Aphids (Eulachnus rileyi Williams) and Their Potential Natural Enemies on Pine Tree Species (Pinus patula and Pinus elliottii) at Sao Hill Forest Plantation, Tanzania

A study was conducted at SHFP, Tanzania to assess the distribution and abundance of PNA and their potential natural enemies. Systematic sampling was used to select every 5th tree along the row of the particular compartment. Five shoots were randomly cut from lower, middle and upper crown parts of each selected tree for laboratory analysis. Data analysis was performed using R and Excel, with normality and homogeneity of variance checked using Shapiro-Wilk and Levene’s tests, respectively. Results revealed that PNA was un-equally distributed throughout the divisions, trees species and age classes at SHFP. The abundance of adult aphids per twig was 7.6 and 12.9 for Division II and III, respectively and was significantly different. Similarly, the mean abundance of eggs and nymphs per twig were 5.5 and 12.2 in Division II and 9.2 and 21.1 in Division III, respectively. Nymphs were more abundant than eggs and adults, while eggs were the least abundant across all examined pine species and age classes. The abundance of adult aphid was 19.6 and 7.0 for P. elliottii and P. patula, respectively and was significantly different. For P. patula, the abundance of adult aphid per twig was 7.3, 8.5 and 5.1 for young, middle and old age classes respectively. In P. elliottii stands, the abundance of adult aphid population per twig was 23.2 and 17.9 for middle and old age classes respectively. The middle part of the tree crown had the highest aphid abundance for both tree species and age classes. Three main natural enemies were identified: Coccinellid beetles (Coleoptera: Coccinellidae), Spiders (Arachnida) and Stink bugs (Pentatomidae), but their numbers were low. The correlation between the abundance of PNA and natural enemies was weakly positive (Rho = 0.0859) but statistically significant (p = 0.035). Tending operations i.e. thinning, weeding, pruning, and regular insect survey and monitoring programs, are recommended to mitigate favorable conditions for aphid growth. Additionally, the SHFP management team should reconsider the introduction and release of Tetraphleps raoi or other predators as biological control agents over large area to increase the current stock of the natural enemies as there were no introduce natural enemies found in the plantation

Pathways for accidental biocontrol: The human-mediated dispersal of insect predators and parasitoids.

Introductions of insect predators and parasitoids for biological control are a key method for pest management. Yet in recent decades, biological control has become more strictly regulated and less frequent. Conversely, the rate of unintentional insect introductions through human activities is rising. While accidental introductions of insect natural enemies can potentially have serious ecological consequences, they are challenging to quantify as their movements go largely unobserved. We used historical border interception records collected by the US Department of Agriculture from 1913 to 2018 to describe the diversity of entomophagous insects transported unintentionally, their main introduction pathways, and trends in host specificity. There were 35,312 interceptions of insect predators and parasitoids during this period, representing 93 families from 11 orders, and 196 species from these families. Commodity associations varied, but imported plants and plant products were the main introduction pathway. Most interceptions originated with commodities imported from the Neotropical, Panamaian, and Western Palearctic regions. Among the intercepted species, 27% were found in material originating from more than one country. Two thirds of species were polyphagous host generalists. Furthermore, 25% of species had already been introduced intentionally as biological control agents internationally, and 4.6% have documented negative impacts on native biodiversity or human society. Most of the intercepted species that have not established in the United States are host generalists or have at least one known host species available. The unintentional transport of diverse natural enemy insects has the potential to cause substantial ecological impacts, both in terms of controlling pests through accidental biocontrol and disrupting native communities. Characterizing the insects being transported and their introduction pathways can inform biosecurity practices and management.

Management of jellyfish outbreaks to achieve good environmental status

Jellyfish and gelatinous zooplankton (GZ) in general, fulfill important ecological roles with significant impacts, although they are often oversimplified or misunderstood. This paper reviews the impacts, pressures, monitoring methods and current management strategies for various GZ groups. It also introduces potentially applicable indicators for their assessment in ecosystem-based management approaches, such as the European Marine Strategy Framework Directive (MSFD). This multi-faceted review is primarily envisioned to serve as a state-of-the-art document for scientists and policymakers to foster a holistic assessment and management of GZ across European regional seas. The systematic review on global impacts of GZ shows a notable increase in the number of studies since the early 2000s. Stings were the main cause of human health impacts. Mechanisms that impact biodiversity included direct predation, modification of trophic flows or competition for resources. Several GZ taxa may be beneficial to biodiversity acting as biological regulators and provide societal ecosystem services such as food provision or medical applications. The systematic review on monitoring techniques outlined a variety of methods, such as nets (the most common technique), continuous plankton recorder (CPR), polyp and jelly-fall monitoring, acoustic methods, remote aerial and underwater imaging, molecular methods, and citizen science. Furthermore, several currently employed management strategies were enumerated, including the use of anti-jelly nets, bubble curtains, chemical compounds, or the introduction of GZ predators. This study highlights the pressing need for enhanced GZ-dedicated monitoring, assessment, and anticipatory management of GZ populations to address future GZ crises more effectively and cost-efficiently. Moreover, exploring GZ ecosystem services unveils opportunities to harness marine resources while mitigating adverse effects, thereby supporting sustainable blue economies.

An Invasive Predator Substantially Alters Energy Flux Without Changing Food Web Functional State or Stability

ABSTRACTUnderstanding how invasive species affect the stability and function of ecosystems is critical for conservation. Here, we quantified the effect of an actively suppressed invasive species on the Yellowstone Lake ecosystem using a food web energetics approach. We compared energy flux, functional state, and stability of four food web states: a pre‐invasion network and three post‐invasion networks undergoing active invasive species suppression, namely, initial invasion, expansion, and decline. Invasion caused ≥ 25% change (±) in energy flux for most consumers, and total flux increased twofold post‐invasion. Flux to the species of conservation concern, Yellowstone cutthroat trout (Oncorhynchus virginalis bouvieri), was 2.8 times less post‐invasion versus pre‐invasion, whereas invasive lake trout (Salvelinus namaycush) flux was up to 17.3 times higher compared to the initial invasion network. The dominant functional state and food web stability did not change post‐invasion, likely due to introduction of a generalist predator and the stabilizing effect of suppression. Lake trout invasion in Yellowstone Lake caused large changes to energy flux, shifting dominant fluxes away from the species of conservation concern, despite not changing functional state or stability. We demonstrate that changes in energy flux may signal invasions in ecosystems, but functional state or stability may not necessarily reflect the magnitude of invasion influences. For invaded fish communities, a better understanding of how the invasive species control the food web beyond just the direct influence on prey can be achieved by investigating energy flux, functional state, and food web stability. Furthermore, evaluating the effect of suppression beyond the invasive species can demonstrate the far‐reaching value of suppression management actions for conservation.

Ambulatory dispersal of Typhlodromus (Anthoseius) recki Wainstein (Acari: Phytoseiidae) along Solanceae stem.

Tomato crops are attacked by several pests, including mites. While the main predatory mites are not effective enough to control mite pests, recent studies have shown encouraging results with the European endemic phytoseiid Typhlodromus (Anthoseius) recki. The first objective of the study was to assess the ability of this species to disperse along the tomato stem, considering six genotypes of Solanum lycopersicum, S. peruvianum and S. cheesmaniae with contrasted trichome numbers and types of stem trichomes, accuratetly characterised in a previous study. The second objective was to determine how predator morphological traits can explain dispersal along the tomato stem. For this, ambulatory dispersal ability of females (stem crossing rate success, hesitation and escape behavior, mobility periods) was tested in lab conditions on the eight Solanum genotypes, at four period of time after the predator introduction (10, 25, 55 and 100min), with a video observation of 5min at each period. The females were then mounted on slides and body length and width (at the fore hind, middle and back parts) measured. No effect of the tomato genotypes was observed on the dispersal ability of the predator. However, specimens that succeeded in crossing the stem, had a higher percentage of mobility time (79.36%) than those that failed (43.60%). Furthermore, body width at midbody (DSW2) and dorsal shield length (DSL) were negatively correlated with dispersal ability. The mean DSL and DSW2 of the females that succeed to cross were 342.3 and 160.9μm, respectively vs. 345.6 and 164.9μm, for females that did not succeed. This suggests that the more slender and relatively small the specimens, the more are mobile and able to successfully cross the stem. The number of glandular trichomes type (GT) VI and to a lesser extent GT I and IV, and non-glandular trichomes (NGT) II&III appear to limit dispersal. The GT VI seems to have a repellent effect. On the opposite, the number of NGT V were positively correlated with high mobility and stem crossing rates. Assuming that the main barrier to biological control efficiency is dispersal along tomato stems, these preliminary results should have implications for biological control success. The proportion of mites with 'optimal dimensions' appears to be low and further studies should be undertaken to better assess the proportion of mites with such ideal dimensions in different populations and also to determine whether these morphological traits are associated with different feeding abilities and/or abiotic conditions.

How can we avoid the extinction of any species naturally? A mathematical model

A large number of herbivorous mammals and reptiles in many terrestrial ecosystems across the globe are presently in the receiving end of extinction. Over-exploitation by its immediate predator and anthropogenic actions is one of the main reasons. Reintroduction of apex predator or top predator at some instances has proven to be a successful strategy in restoring ecological balance. In this paper, we conceptualize the role of top predator in enriching the density of vulnerable species of lower trophic level, with the help of mathematical modeling. First, the dynamical behavior of two species system (prey and mesopredator) is studied, where growth of prey is subject to strong Allee effect. Also, the cost of predation induced fear is incorporated in the growth term. Parametric regions, for which the species perceive extinction risk are analyzed and depicted numerically. We consider that whenever density of the vulnerable species reach a certain threshold, minimum viable population, top predator is introduced in the habitat. Our obtained results show that a species population can be restored from the verge of extinction to a stable state with much higher population density with the introduction of top predator and even it stabilizes an oscillatory system.

Prevalence of Pathogens in Free-Living Adult Chimango Caracaras (Milvago chimango) in Three Areas with Different Levels of Urbanization in the Pampas Ecoregion, Argentina

ABSTRACT Urbanization can adversely impact animal populations through factors such as loss of natural habitat, introduction of nonnative competitors and predators, pollution, and increased exposure to pathogens. Because they are top predators, raptors are considered good indicators of ecosystem health. However, there is limited information about how environmental factors associated with urbanization can alter raptors’ susceptibility to pathogens. We evaluated exposure to selected pathogens of the Chimango Caracara (Milvago chimango), a generalist and opportunistic species endemic to South America. This species is distributed over a wide range of environments, including urban areas, and often takes advantage of human-generated resources such as domestic waste, urban garbage, and carrion, potentially increasing its exposure to pathogens. We captured adult Chimango Caracaras in three areas that varied in level of urbanization, in the southeastern region of the Buenos Aires Province, Argentina. Captured individuals were tested for exposure to Bacillus anthracis, Salmonella spp., and Trichomonas spp. All individuals tested were negative for these pathogens. Whether this represents a true lack of exposure to these microorganisms, the ability of this raptor to effectively inhibit the colonization of the gastrointestinal tract by these microorganisms, or an inability of the pathogen to colonize the Chimango Caracara’s gastrointestinal tract remains to be determined. This is the first study to assess the prevalence of selected pathogens in Chimango Caracaras inhabiting areas with different levels of urbanization.

Problems and perspectives for the use of exotic predators and parasitoids in biological control

The accidental introduction of alien organisms potentially harmful to agriculture can cause extensive damage to vegetable crops and fruit plants and is favoured by the global mobility of people, trade of goods and the ongoing climate change. The use of alien predators and parasitoids is well known in the agricultural field, where they are often used for biological control to protect fruit and horticultural plants. The management of invasive species is and will be one of the key issues for preserving biodiversity and the profitability of crops, the latter can now count on an effective, consolidated and lasting strategy: Integrated Pest Management (IPM). The legislation on this subject is complex and articulated and is continuously being updated. It allows for the development of specific skills in biological control and the availability to use quarantine chambers where it is possible to breed and study the behaviour of antagonists (predators and parasitoids), even exotic ones. If successful, their subsequent release to targeted biological control interventions of infestations of the IAS ‘Invasive Alien Species’ can be carried out. This contribution highlights the risk that such practices may involve and takes into account the following points: 1. The behaviour of an alien species can be very different in different contexts, being able to be a real IAS or not showing any character of invasiveness; 2. The behavior of an alien species can vary over time in the same context, diversifying and also expanding its trophic niche; 3. A good number of indigenous predators and parasitoids can over time adapt to new alien prey/hosts and could potentially be used for biological control. In future, biological control will be increasingly used given that EU funds reward and support this type of approach and the intentional introduction of alien natural predators and parasitoids into agroecosystems, although subject to strict protocols, cannot exclude spontaneous colonization by these last of natural environments with currently not assessable consequences on their biocoenosis. In conclusion, the rigorous risk analysis alone does not currently seem sufficient to exclude potential damage to local biodiversity, and programs for the release of exotic predators and parasitoids should be associated with mandatory monitoring of at least five years to verify the behaviour of these aliens in nature and their possible impact on ecosystems.

Effect of predators on Anopheles arabiensis and Anopheles funestus larval survivorship in Homa Bay County Western Kenya

BackgroundThe rise of insecticide resistance against malaria vectors in sub-Saharan Africa has resulted in the need to consider other methods of vector control. The potential use of biological methods, including larvivorous fish, Bacillus thuringiensis israelensis (Bti) and plant shading, is sustainable and environmentally friendly options. This study examined the survivorship of Anopheles arabiensis and Anopheles funestus larvae and habitat productivity in four permanent habitat types in Homa Bay county, western Kenya.MethodsPredator densities were studied in a laboratory setup while habitat productivity and larval survivorship was studied in field setup.ResultsFish were observed as the most efficient predator (75.8% larval reduction rate) followed by water boatman (69%), and dragonfly nymph (69.5%) in predation rates. Lower predation rates were observed in backswimmers (31%), water beetles (14.9%), water spiders (12.2%), mayflies (7.3%), and tadpoles (6.9%). Increase in predator density in the field setup resulted in decreased Culex larval density. Larval and pupa age–specific distribution was determined and their survivorship curves constructed. Combined larvae (Stage I–IV) to pupa mortality was over 97% for An. arabiensis and 100% for An. funestus. The highest larval stage survival rate was from larval stages I to II and the lowest from larval stage IV to pupa. Stage-specific life tables indicated high mortality rates at every developmental stage, especially at the larval stage II and III.ConclusionDetermination of the efficiency of various larval predators and habitat productivity will help with the correct identification of productive habitats and selection of complementary vector control methods through environmental management and/or predator introduction (for instance fish) in the habitats.

The impact of predators of mosquito larvae on Wolbachia spreading dynamics

Dengue fever creates more than 390 million cases worldwide yearly. The most effective way to deal with this mosquito-borne disease is to control the vectors. In this work we consider two weapons, the endosymbiotic bacteria Wolbachia and predators of mosquito larvae, for combating the disease. As Wolbachia-infected mosquitoes are less able to transmit dengue virus, releasing infected mosquitoes to invade wild mosquito populations helps to reduce dengue transmission. Besides this measure, the introduction of predators of mosquito larvae can control mosquito population. To evaluate the impact of the predators on Wolbachia spreading dynamics, we develop a stage-structured five-dimensional model, which links the predator-prey dynamics with the Wolbachia spreading. By comparatively analysing the dynamics of the models without and with predators, we observe that the introduction of the predators augments the number of coexistence equilibria and impedes Wolbachia spreading. Some numerical simulations are presented to support and expand our theoretical results.

Toggling between food-seeking and self-preservation behaviors via hypothalamic response networks

Motivated behaviors are often studied in isolation to assess labeled lines of neural connections underlying innate actions. However, in nature, multiple systems compete for expression of goal-directed behaviors via complex neural networks. Here, we examined flexible survival decisions in animals tasked with food seeking under predation threat. We found that predator exposure rapidly induced physiological, neuronal, and behavioral adaptations in mice highlighted by reduced food seeking and consumption contingent on current threat level. Diminishing conflict via internal state or external environment perturbations shifted feeding strategies. Predator introduction and/or selective manipulation of danger-responsive cholecystokinin (Cck) cells of the dorsal premammilary nucleus (PMd) suppressed hunger-sensitive Agouti-related peptide (AgRP) neurons, providing a mechanism for threat-evoked hypophagia. Increased caloric need enhanced food seeking under duress through AgRP pathways to the bed nucleus of the stria terminalis (BNST) and/or lateral hypothalamus (LH). Our results suggest oscillating interactions between systems underlying self-preservation and food seeking to promote optimal behavior.

Principles and strategies of biological control economically harmful forest organisms

Essentially, biological control is nothing but applied ecology, ie the use of natural enemies to (regulatory) reduce abundance in pest populations. Intellectually satisfying, biologically intriguing and ecologically rational, a means of pest control, biological control, is one of the areas of integrated management and protection of forest ecosystems, which is rapidly developing and brings together scientists from many disciplines. Ecologists, entomologists, pathologists of plants and insects, microbiologists, approach the subject of research from different angles. Each discipline uses biological control in order to reduce the number of pests or pathogens, through the activity of beneficial living organisms. Biological control of economically harmful forest organisms means that those who decide on its application in specific environmental conditions should first accurately identify the type of pest, assess the level of infestation and predict potential economic damage, explore all available strategies, their advantages and disadvantages, and select the most efficient, which must be in correlation with all applicable local, national and international regulations. Within the biological control of pests, mainly insects, various strategies are used, which basically include the introduction of natural enemies, predators, parasitoids and pathogens, indigenous and allochthonous harmful insect species (classical and inoculation biological control) and increasing their numbers (inundative biological suppression). It should be noted here that the legislation in the field of nature and environmental protection prohibits the introduction of allochthonous, exotic species into natural and anthropogenic ecosystems in many countries, and therefore, the application of biological control is quite limited. A special, promising, strategy within biological control is the selection of strains with genetically induced ability of autocidal action. Entomopathogenic organisms, various types of viruses, microsporidia, bacteria, protozoa, fungi, which under favorable conditions can cause mass death of insects, live normally in nature and are important regulatory factors in host populations. Epizootics caused by natural viral and fungal pathogens are often responsible for spectacular crashes in populations of graded species, e.g. gubara, žutotrbe, ordinary and red pine sol. Despite such brilliant characteristics, a small number of them are included in certain biological control strategies. Suppression of plant pathogens can rarely be achieved without a careful combination of many techniques. Legislation in the field of nature and environmental protection in many countries prohibits the introduction of non-native, exotic species, and thus, the application of a number of biological control strategies is prevented.The application of fungicides in forest ecosystems is usually too expensive, so biological control measures are preferred, through the use of antagonistic or hypovirulent species of microorganisms and their strains. In essence, when it comes to plant pathogens, biological control measures are more preventive than palliative or curative, and are based on sustainable ecological concepts of forest ecosystems.

Fishing for hosts: Larval spurting by the endangered thick-shelled river mussel, Unio crassus.

Fishing for hosts: Larval spurting by the endangered thick-shelled river mussel, Unio crassus.

Climate change disrupts core habitats of marine species.

Driven by climate change, marine biodiversity is undergoing a phase of rapid change that has proven to be even faster than changes observed in terrestrial ecosystems. Understanding how these changes in species composition will affect future marine life is crucial for conservation management, especially due to increasing demands for marine natural resources. Here, we analyse predictions of a multiparameter habitat suitability model covering the global projected ranges of >33,500 marine species from climate model projections under three CO2 emission scenarios (RCP2.6, RCP4.5, RCP8.5) up to the year 2100. Our results show that the core habitat area will decline for many species, resulting in a net loss of 50% of the core habitat area for almost half of all marine species in 2100 under the high-emission scenario RCP8.5. As an additional consequence of the continuing distributional reorganization of marine life, gaps around the equator will appear for 8% (RCP2.6), 24% (RCP4.5), and 88% (RCP8.5) of marine species with cross-equatorial ranges. For many more species, continuous distributional ranges will be disrupted, thus reducing effective population size. In addition, high invasion rates in higher latitudes and polar regions will lead to substantial changes in the ecosystem and food web structure, particularly regarding the introduction of new predators. Overall, our study highlights that the degree of spatial and structural reorganization of marine life with ensued consequences for ecosystem functionality and conservation efforts will critically depend on the realized greenhouse gas emission pathway.

Experts’ opinions on threats to Leach’s Storm-Petrels ( Hydrobates leucorhous ) across their global range

Seabirds are declining globally, though the threats they face differ among and within species and populations. Following substantial population declines at several breeding colonies, Leach’s Storm-Petrel (<em>Hydrobates leucorhous</em>) was uplisted from Least Concern to Vulnerable by the International Union for Conservation of Nature (IUCN) in 2016. Reasons for these declines are unclear, and it is important to identify threats the species faces across its global breeding range to guide research directions and inform conservation efforts. We solicited feedback from 37 Leach’s Storm-Petrel scientific experts from eight countries on the importance of different threats facing the species on land and at sea. Perceived threats to extant colonies varied spatially, with a consensus within regions for main threats. Most researchers agreed that the main threats at or near colonies are avian and mammalian predators and onshore light attraction. At-sea threats have been less studied and were harder to identify and rank, but include offshore lights and structures, spatial shifts in prey, and contaminants. Climate change was not listed specifically because of its multifaceted repercussions, but several perceived threats are linked to climate change. Globally, introduction of mammalian predators is an overarching driver of seabird colony decline or extirpation; thus biosecurity must be considered an important measure for the conservation of storm-petrels. In addition, filling knowledge gaps and implementing a series of regionally relevant and targeted strategies that lead to small but cumulative conservation successes may be the best approach for this species.

BISTABILITY, GENERALIZED AND ZERO-HOPF BIFURCATIONS IN A PEST CONTROL MODEL WITH FARMING AWARENESS

Introduction of biopesticides and predators in the crop fields has a crucial impact on the pest management as the biopesticides induce infection among the pest population and the infected pests are easy to be captured by the predators. In this paper, we investigate a mathematical model for a pest management system with farming awareness-based inclusion of predators and biopesticides. The level of awareness among the farmers is assumed to grow at a constant rate besides its growth due to an increase in the pest population in the crop field. The proposed model is analyzed mathematically for the feasibility and stability of the equilibrium points; existence of Hopf bifurcation together with direction and stability of the bifurcating periodic solutions are discussed; sufficient conditions are derived for which the system does not exhibit any periodic solution. Our simulation results show that the activeness of farmers for employing biopesticides in the crop field potentially suppresses the oscillations and brings forth stability in the system. Further, we observe that the system showcases the appearances of Generalized Hopf bifurcation, Zero-Hopf bifurcation, transcritical bifurcation and bistability. Overall, our findings manifest that by imparting knowledge among the farmers regarding the use of biopesticides and predators in the crop fields, the pest population can be effectively controlled.

Commentary: using prey naïveté to inform ecological management.

Commentary: using prey naïveté to inform ecological management.

Compatibility of biological control and pesticides mediated by arthropod movement behavior and field spatial scale

Integrated pest management programs frequently rely on a combination of pesticide use with cultural controls such as diversifying agroecosystems to control pest populations. Selective pesticides can impose both lethal and sublethal effects on natural enemies. However, understanding the compatibility of pesticide use with biological control strategies is critical for pest management success. The population dynamics of natural enemies subjected to the effects of pesticides, especially those that experience sublethal effects, is critical to this understanding. Although lethal effects of pesticides on natural enemies are well-studied, sublethal effects of pesticide exposure such as the impact on natural enemy movement is less well understood – especially across different habitat spatial scales. We present a simulation model using coupled partial differential equations to explore the sublethal effects of pesticide use, via reduced predator movement, on pest suppression across a gradient of farm spatial scales. Using a beetle-aphid model system, we find that in small fields, increased abundance of natural enemies can reduce the need for pesticide sprays. However, in mid-sized fields, we find that impaired predator mobility caused by pesticide sprays has a negative impact on biological control by the natural predator community. We also demonstrate how timing of predator introduction to a field can complement timing of pesticide sprays. We discuss the implications of these results for biological control planning and implementation.

Oxidative stress and behavioral responses of moorish geckos (Tarentola mauritanica) submitted to the presence of an introduced potential predator (Hemorrhois hippocrepis)

Stressful situations induce an increase in the production of reactive oxygen species (ROS) which can lead to molecular damage and alteration of cell function. The introduction of new potential predators induces physiological stress in native fauna. However, behavioral responses have been reported in preys, demonstrating an induction of the defenses against alien species. Behavioral and antioxidant enzyme responses in the moorish gecko, Tarentola mauritanica, against the invasive predator horseshoe whip snake (Hemorrhois hippocrepis) were assessed. Behavior was recorded and a tissue sample from the tail was collected after placing the gecko in a terrarium with previous absence or presence of the snake in ‘Control’ and ‘H. hippocrepis’ groups, respectively. Fifteen behavioral variables were examined, including tongue flick (TF) and locomotion patterns. Antioxidant enzyme activities -catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR)-, and the levels of reduced (GSH) and oxidized glutathione (GSSG), glutathione/glutathione disulfide ratio (GSH/GSSG) and malondialdehyde (MDA) concentrations were measured in the tissue sampled. Geckos exposed to the snake's odor showed a higher number of TF, longer amounts of time remaining motionless or moving in slow motion and they spent less time on the ground in comparison to the ‘Control’ group. The presence of the snake produced a significant increase in the activities of CAT, SOD and GR and a decrease in the GSH/GSSG ratio in T. mauritanica individuals exposed to the snake's scent. Thus, both behavioral responses and oxidative stress biomarkers clearly showed that T. mauritanica is able to recognize H. hippocrepis as a potential predator, despite being a recently introduced snake at the Balearic Islands.

Something went missing: cessation of Traditional Owner land management and rapid mammalian population collapses in the semi-arid region of the Murray&amp;#x2013;Darling Basin, southeastern Australia

The nineteenth century mass mammal extinctions in the semi-arid zone of the Murray&amp;#x2012;Darling basin, southeastern Australia, are examined in the context of prior traditional land management. A model of grassland dynamics reveals a multi-trophic level productive pulse one to five years post-fire, followed by senescence and increasing flammability. Traditional Owner patch burning of grassland optimized human and mammalian food (including tubers, seeds and fungi) and decreased fire risk. Over at least 40 000 years, the persistence and abundance of fauna responded to this energetically closed self-reinforcing management. In 1830, depopulation (disease, massacres and displacement) effectively ended traditional management, an ecologically traumatic event that extinguished these productivity pulses. Associated mammal populations of c. 20 species collapsed, and all eco-engineering and mycophagous species, such as bilbies, bettongs and bandicoots, rapidly disappeared. Traditional land management increased productivity, habitat heterogeneity and reduced wildfire risk, underpinning mammal abundance. This has remained unrecognized by most mammalogists and land managers. Blaming extinctions predominantly on the additions by Europeans (introduction of ungulates, feral grazers and predators etc.), disastrous as they were, fails to acknowledge the initial cause of rarity, i.e. loss of productivity, habitat and niches when traditional management was subtracted from country. As ecosystems continue to degrade, understanding the primary cause is fundamental to improved management. Although too late for extinct species, respect for, and inclusion of, traditional land management knowledge provides a direction for future land management.