scholarly journals Severe disturbance overflows the stabilizing buffer of variable biotic interactions

2021 ◽  
Author(s):  
Koya Hashimoto ◽  
Daisuke Hayasaka ◽  
Yuji Eguchi ◽  
Yugo Seko ◽  
Ji Cai ◽  
...  
Keyword(s):  
Interaction Strength ◽  
Biotic Interactions ◽  
Anthropogenic Disturbances ◽  
Biotic Interaction ◽  
Pesticide Application ◽  
Community Resistance ◽  
Over Time ◽  
Severe Disturbance ◽  
Outdoor Mesocosms ◽  
Freshwater Community

Recent studies have uncovered that biotic interaction strength varies over time in real ecosystems intrinsically and/or responding to anthropogenic disturbances. Little is known, however, about whether such interaction variability strengthens or weakens community resistance against disturbances. Here, we examine how the change in interaction strength after pesticide application mediates disturbance impacts on a freshwater community using outdoor mesocosms. We show that the change in interaction strength buffered the disturbance impact but amplified it once the disturbance severity exceeded a certain threshold. Importantly, we also show that interactions fluctuating more temporally under no disturbances were more changeable in response to pesticide applications. Our findings suggest that a severe disturbance may have a surprise impact on a biological community amplified by their own interaction variability, but the possibility still remains that we can predict the consequences of the disturbance by measuring the interaction variability before the disturbance occurs.

scholarly journals Adaptation and latitudinal gradients in species interactions: nest predation in birds

2019 ◽  
Author(s):  
Benjamin G. Freeman ◽  
Micah N. Scholer ◽  
Mannfred M. A. Boehm ◽  
Julian Heavyside ◽  
Dolph Schluter
Keyword(s):  
Nest Predation ◽  
Species Interactions ◽  
Interspecific Interactions ◽  
Interaction Strength ◽  
Biotic Interactions ◽  
Western Hemisphere ◽  
Evolutionary Rates ◽  
Latitudinal Gradients ◽  
Biotic Interaction ◽  
The Tropics

AbstractThe “biotic interactions” hypothesis—that stronger interspecific interactions in the tropics drive faster evolution and speciation, giving rise to the latitudinal diversity gradient—has inspired many tests of whether certain biotic interactions are indeed stronger in the tropics. However, the possibility that populations have adapted to latitudinal differences in species interactions, blunting effects on evolutionary rates, has been largely ignored. Here we show that mean rates of nest predation experienced by land birds vary minimally with latitude in the Western Hemisphere. This result is surprising because nest predation in birds is a canonical example of a strong tropical biotic interaction. We explain our finding by demonstrating that (1) rates of nest predation are in fact higher in the tropics, but only when controlling for the length of the nesting period, (2) long nesting periods are associated with reduced predation rates, and (3) tropical birds have evolved particularly long nesting periods. We suggest this is a case example of how adaptation to a biotic interaction can alter observed latitudinal gradients in interaction strength, potentially equalizing evolutionary rates among latitudes. More broadly, we advocate for tests of the biotic interactions hypothesis to consider both latitudinal patterns in interaction strength and evolutionary responses to these interactions.

Anthropogenic perturbation modifies interactions between mammals and fruits in a tropical forest of southern Mexico

2021 ◽  
Vol 71 (3) ◽  
pp. 311-327
Author(s):  
Mayra Zamora-Espinoza ◽  
Juan Carlos López-Acosta ◽  
Eduardo Mendoza
Keyword(s):  
Daily Activity ◽  
Interaction Strength ◽  
Biotic Interactions ◽  
Camera Traps ◽  
Canis Lupus Familiaris ◽  
Mammalian Fauna ◽  
Mammal Species ◽  
Southern Mexico ◽  
Field Station ◽  
The Impact

Abstract Studies of tropical mammal defaunation highlight the loss of species as well as their reduction in abundance and diversity; however, there is a complex series of effects associated with this anthropogenic disruption, including increases in the relative abundance of disturbance-tolerant mammals and the arrival of alien mammals whose effects on biotic interactions have been poorly studied. We compared the species richness, composition, interaction strength, and patterns of daily activity of mammals that consume the fruits of Pouteria sapota on the forest floor, both inside and outside of the Los Tuxtlas Field Station (LTFS) in Veracruz, southern Mexico. Using camera traps, we recorded eight mammal species interacting with the fruits inside the LTFS ( trees) and nine species interacting outside ( trees). Alien species such as Canis lupus familiaris were recorded both inside and outside of the LTFS, whereas Bos taurus was only recorded outside. Medium-sized generalist mammals were overrepresented both inside and outside of the LTFS, evidencing an impoverishment of the fauna, when compared to the mammal assemblage reported to interact with P. sapota fruits in a more intact forest. The daily activity patterns of the mammals that interacted strongly with P. sapota fruits were different inside and outside the LTFS, particularly in the case of Cuniculus paca. Our results show that the impact of human activity is highly pervasive, directly affecting the mammalian fauna at different levels and indirectly affecting the biotic interactions in which these animals are involved.

Landscape Heterogeneity and Dynamics

2019 ◽  
pp. 42-126
Author(s):  
Kimberly A. With
Keyword(s):  
Landscape Ecology ◽  
Spatial Heterogeneity ◽  
Landscape Structure ◽  
Landscape Heterogeneity ◽  
Spatial Scales ◽  
Anthropogenic Disturbances ◽  
Ecological Processes ◽  
Disturbance Dynamics ◽  
Wide Range ◽  
Over Time

Heterogeneity is a defining characteristic of landscapes and therefore central to the study of landscape ecology. Landscape ecology investigates what factors give rise to heterogeneity, how that heterogeneity is maintained or altered by natural and anthropogenic disturbances, and how heterogeneity ultimately influences ecological processes and flows across the landscape. Because heterogeneity is expressed across a wide range of spatial scales, the landscape perspective can be applied to address these sorts of questions at any level of ecological organization, and in aquatic and marine systems as well as terrestrial ones. Disturbances—both natural and anthropogenic—are a ubiquitous feature of any landscape, contributing to its structure and dynamics. Although the focus in landscape ecology is typically on spatial heterogeneity, disturbance dynamics produce changes in landscape structure over time as well as in space. Heterogeneity and disturbance dynamics are thus inextricably linked and are therefore covered together in this chapter.

scholarly journals Prospects and Constraints of Madhupur National Park Management

2012 ◽  
Vol 5 (1) ◽  
pp. 151-158
Author(s):  
MY Mia ◽  
MU Hossain ◽  
S Farzana
Keyword(s):  
Natural Resources ◽  
National Parks ◽  
National Park ◽  
Deciduous Forest ◽  
Anthropogenic Disturbances ◽  
Park Management ◽  
Reserve Forest ◽  
Agro Forestry ◽  
Over Time ◽  
Local Leaders

The study was conducted in Madhupur National Park (MNP), which is very well known for its characteristics as deciduous forest.  This study examined the constraints of park management, causes of deforestation and prospects of Madhupur Sal forests of Bangladesh. Data were collected from the Madhupur National Park authority and a study was done to have clear scenario of the park management and status of forest over time. It is evident from the study that due to various factors like anthropogenic disturbances, political abusement, absence of proper rules and regulations, willingless of the authority, encroachment of forest by locals/local leaders, illegal cutting of Sal trees, agro-forestry, and lack of adequate budget are main constraints for managing MNP. The study also revealed that about 1-3% of the forest is depleted each year, and about 50-80 years later, the forest will be completely vanished or scattered in somewhere. However, MNP will be a sustainable reserve forest for Sal trees and other flora and fauna, and also be a potential ecotourism spot, if it is properly managed. Findings of the study will help to identify the prospects and constraints of MNP and also in other National Parks in Bangladesh which ultimately conserve the biodiversity and help to maintain natural balance. DOI: http://dx.doi.org/10.3329/jesnr.v5i1.11570 J. Environ. Sci. & Natural Resources, 5(1): 151 - 158, 2012

Restoration for Resistance to Invasion by Giant Reed (Arundo donax)

2009 ◽  
Vol 2 (4) ◽  
pp. 279-291 ◽  
Author(s):  
Lauren D. Quinn ◽  
Jodie S. Holt
Keyword(s):  
Species Composition ◽  
Community Composition ◽  
Environmental Parameters ◽  
Invasion Success ◽  
Giant Reed ◽  
Planting Density ◽  
Late Winter ◽  
Community Resistance ◽  
Natural Recruitment ◽  
Over Time

AbstractThe relationship between plant community composition and invasibility has been studied extensively but seldom in the context of ecosystem restoration. Experimental riparian restoration plots differing in species composition and density were established and evaluated for susceptibility to invasion by giant reed, a common riparian invader in California, and natural recruitment by riparian species over time. Plots were planted in 2002 with cuttings of common threesquare (a sedge), seepwillow (a shrub), and Goodding's willow (a tree) at two densities in monoculture and all possible mixture combinations. Giant reed rhizomes were introduced into half of the plots in the spring of 2003, while the remaining plots were allowed to undergo natural recruitment for an additional year. In late winter 2004, giant reed rhizomes were planted in the remaining plots. Both planting groups were followed for one growing season to evaluate giant reed establishment, survival, and growth. Community composition affected giant reed performance, particularly in 2003 before natural recruitment occurred. In that year, plots containing seepwillow + willow had the lowest giant reed shoot production, growth, and survival. All plots containing seepwillow were resistant to colonization by natural recruitment in 2004, but none of the planting treatments affected giant reed success in that year. Giant reed was more successful overall in 2004 despite deeper shade and drier soils. This pattern could be attributed to larger initial rhizome size in 2004, which allowed giant reed to overcome environmental stress during establishment. Planting density did not impact giant reed or natural recruitment independently, but may affect environmental parameters and warrants further study as a potential contributor to restoration success. Our results indicate that choice of species composition in restoration might impact giant reed invasion success initially, but community resistance might not be sustainable and maintenance-free over time.

Beak condition drives abundance and grooming-mediated competitive asymmetry in a poultry ectoparasite community

Parasitology ◽  
2011 ◽  
Vol 138 (6) ◽  
pp. 748-757 ◽  
Author(s):  
BRIAN L. CHEN ◽  
KATHRYN L. HAITH ◽  
BRADLEY A. MULLENS
Keyword(s):  
White Leghorn ◽  
Lower Abdomen ◽  
Pesticide Application ◽  
Worker Exposure ◽  
Ornithonyssus Sylviarum ◽  
Northern Fowl Mite ◽  
Enemy Free Space ◽  
Reciprocal Transfer ◽  
Beak Trimming ◽  
Over Time

SUMMARYObjective.Ornithonyssus sylviarum(northern fowl mite) andMenacanthus stramineus(chicken body louse) are key poultry pests currently controlled by exclusion or pesticide application. We studied how host beak condition affected their populations over time and how the lice and mites might interact on a host.Methods. Beak-trimmed or beak-intact white leghorn hens were infested initially with either mites or lice and subsequently challenged using the alternate ectoparasite species (reciprocal transfer), while other hens harboured only the initial ectoparasite species.Results. Beak-trimmed hens had far higher ectoparasite numbers relative to beak-intact hens, and the 2 ectoparasites showed evidence of grooming-mediated competitive asymmetry. On beak-trimmed hens, larger numbers of lice quickly nearly completely excluded mites in competition for enemy-free space (lower abdomen), while in the reciprocal transfer mites did not affect louse numbers on beak-trimmed hosts. The 2 ectoparasites co-existed on beak-intact hens, which were better able to defend the lower abdomen habitat by grooming.Conclusion. Lice are somewhat less damaging and much easier to control relative to mites, and might be used to eliminate mites in commercial, beak-trimmed flocks. Beak trimming impairs host grooming and contributes greatly to the high ectoparasite populations seen in commercial flocks. The study adds incentives for poultry breeders to develop more docile hen strains that can be held without beak trimming. This has advantages both to welfare advocates and producers who may no longer need to use insecticides for pest control or be concerned about worker exposure to pesticides.

scholarly journals Competitive ability of native and alien plants: effects of residence time and invasion status

NeoBiota ◽  
2021 ◽  
Vol 65 ◽  
pp. 47-69
Author(s):  
Christine S. Sheppard ◽  
Marco R. Brendel
Keyword(s):  
Residence Time ◽  
Intraspecific Competition ◽  
Native Species ◽  
Competitive Ability ◽  
Biotic Interactions ◽  
Invasion Success ◽  
Competitive Response ◽  
Competitive Effects ◽  
Per Capita ◽  
Over Time

Competition is commonly thought to underlie the impact of plant invasions. However, competitive effects of aliens and competitive response of natives may also change over time. Indeed, as with time, the novelty of an invader decreases, the accumulated eco-evolutionary experience of resident species may eventually limit invasion success. We aimed to gain insights on whether directional changes in biotic interactions over time or more general differences between natives and aliens, for instance, resulting from an introduction bias, are relevant in determining competitive ability. We conducted a pairwise competition experiment in a target-neighbour design, using 47 Asteraceae species with residence times between 8 years-12,000 years in Germany. We first tested whether there are differences in performance in intraspecific competition amongst invasion status groups, that is casual and established neophytes, archaeophytes or native species. We then evaluated whether competitive response and effects depend on residence time or invasion status. Lastly, we assessed whether competitive effects influence range sizes. We found only limited evidence that native target species tolerate neighbours with longer potential co-existence times better, whereas differences in competitive ability were mostly better explained by invasion status than residence time. Although casual neophytes produced most biomass in intraspecific competition, they had the weakest per-capita competitive effects on natives. Notably, we did not find differences between established neophytes and natives, both of which ranked highest in interspecific competitive ability. This lack of differences might be explained by a biased selection of highly invasive or rare native species in previous studies or because invasion success may result from mechanisms other than interspecific competitive superiority. Accordingly, interspecific per-capita competitive effects did not influence range sizes. Further studies across a broader range of environmental conditions, involving other biotic interactions that indirectly influence plant-plant interactions, may clarify when eco-evolutionary adaptations to new invaders are a relevant mechanism.

scholarly journals Four cases of prey-predator interaction (anuran-snake) through their geographical distribution

2019 ◽  
Vol 2 (1) ◽  
pp. 31
Author(s):  
José Luis Aguilar-López
Keyword(s):  
Geographical Distribution ◽  
New Records ◽  
Geographical Location ◽  
Biotic Interactions ◽  
Biotic Interaction ◽  
Biological Interaction ◽  
Snake Species ◽  
Interacting Species ◽  
Anuran Species

The biotic interaction prey-predator between one anuran species and one snake species, in some cases have been reported just in one geographical location, and in other cases have been reported several records through the geographical distribution of both interacting species. In this study we report four cases of anurans predation by snakes in different geographical location to the previous records. The previous and new records suggest that the biological interaction prey-predator between two species is maintained regardless of the geographical location and elevation. The consequences of these kind of biotic interactions for the predator and prey requires further study.

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