Microclimatic edge effects in a fragmented forest: disentangling the drivers of ecological processes in plant‐leafminer‐parasitoid food webs

Deforestación extensiva en el Amazonas ha creado una selva bastante fragmentada en regiones con tasas altas de deforestación y de uso del fuego para limpia y mantenimiento de terrenos. El bosque en la interfase con estas deforestaciones sufre cambios drásticos en microclima, vegetación y procesos ecológicos, los cuales son favorables para la combustión bajo las copas después de una sequía prolongada. Un incremento en el uso del fuego, aunado a una mayor área de bosque vulnerable a incendios es una amenaza para la integridad y sustentabilidad de selvas tropicales. Se presentan resultados de estudios conducidos en Mato Groso de 1997 al 2003 como parte de experimentos para estudiar combustión de biomasa, tasas de liberación de carbono y flamabilidad de selvas. Se monitorearon cambios en susceptibilidad a incendios en la interfase entre el bosque y áreas recientemente deforestadas durante la temporada de sequía, al final de la cual se desarrollaron quemas experimentales. Abstract Extensive deforestation in the Amazon has created a highly fragmented forest in regions with an extensive rate of land use conversion and use of fire for land clearing, agriculture and grassland maintenance. The forest on the interface with land clearings suffers drastic changes in micro weather, vegetation, and ecological processes. Those altered conditions are favorable to sustaining understory fires after a prolonged drought. An increasing amount of fire usage, coupled with large areas of forest vulnerable to fire creates a new threat to the integrity and sustainability of the tropical forests in Amazonia and elsewhere in the tropical world. This paper presents the results of experimental burnings conducted from 1997 to 2003 in Mato Grosso. The study monitored the change in vulnerability of the interface between primary forest and recent deforested patches, monitored fire behavior and depth of fire penetration in the undisturbed forest on the edge of land clearing.

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Edge Effects Are Not Linked to Key Ecological Processes in a Fragmented Biogenic Reef

Estuaries and Coasts ◽

10.1007/s12237-020-00705-4 ◽

2020 ◽

Vol 43 (4) ◽

pp. 708-721 ◽

Cited By ~ 1

Author(s):

Camilla Bertolini ◽

W. I. Montgomery ◽

Nessa E. O’Connor

Keyword(s):

Edge Effects ◽

Ecological Processes

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Temporal edge effects structure the assemblages of Drosophilidae (Diptera) in a Restinga forest fragment in Southern Brazil

Neotropical Biology and Conservation ◽

10.3897/neotropical.16.e61481 ◽

2021 ◽

Vol 16 (2) ◽

pp. 299-315

Author(s):

Mayara Ferreira Mendes ◽

Monica Laner Blauth ◽

Luana Amaral Dos Santos ◽

Vera Lúcia da Silva Valente Gaiesky ◽

Marco Silva Gottschalk

Keyword(s):

Decision Making ◽

Edge Effects ◽

Seasonal Patterns ◽

Southern Brazil ◽

Forest Fragment ◽

Ecological Processes ◽

Fragmented Landscapes ◽

Anthropogenic Habitat ◽

South Of Brazil ◽

Asymmetrically Distributed

Anthropogenic habitat fragmentation directly affects ecological processes, leading to negative biodiversity impacts for insects and other biota. Increased edge effects are one consequence of fragmentation, and may alter the composition or abundance of species in the remaining habitat fragments. Understanding the ways in which edge effects impact upon the biota is essential for conservation decision-making in fragmented landscapes. Therefore, the aim of this study was to analyze the seasonal patterns of abundance, richness, and composition of Drosophilidae in a Restinga forest fragment in the extreme south of Brazil, as a function of the distance from the edge to the interior of the fragment. The data were analyzed using SIMPER analyses, which showed that the edge and the forest interior were most dissimilar during winter, followed by spring, autumn and summer. An NMDS and the SIMPER analyses showed that the lower dissimilarity between the edge and interior in spring, autumn and summer, compared to winter, is driven by immigration of individuals from outside of the forest fragment. Furthermore, some species were asymmetrically distributed in the fragment, with some species restricted to the edge of the fragment and others to the interior. This information aids in the understanding of the functioning and dynamics of fragmentation, which is fundamental for the maintenance and integrity of environments and their fauna.

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Medium-sized exotic prey create novel food webs: the case of predators and scavengers consuming lagomorphs

PeerJ ◽

10.7717/peerj.2273 ◽

2016 ◽

Vol 4 ◽

pp. e2273 ◽

Cited By ~ 14

Author(s):

Facundo Barbar ◽

Fernando Hiraldo ◽

Sergio A. Lambertucci

Keyword(s):

Food Web ◽

Food Webs ◽

Apparent Competition ◽

Ecological Processes ◽

Novel Food ◽

Food Web Interactions ◽

Conservation Actions ◽

Upper Level ◽

Native Diversity ◽

Analytical Tools

Food web interactions are key to community structure. The introduction of species can be seen as an uncontrolled experiment of the addition of species. Introduced species lead to multiple changes, frequently threatening the native biodiversity. However, little is known about their direct effect on the upper level of the food web. In this study we review empirical data on the predator–prey relationship between the introduced lagomorphs and their consumers, and use meta-analytical tools to quantify the strength of their interactions. We expect that exotic lagomorphs will destabilize food webs, affect ecological processes and compromise the conservation of the invaded regions. We found 156 studies on the diet of 43 species of predators that consume lagomorphs as exotic preys in South America and Oceania. We found an average exotic lagomorphs-predator link of 20% which indicates a strong interaction, given that the average for the strongest links with native prey (when lagomorphs are not included in the predator diet) is about 24%. Additionally, this last link decreases to 17% when lagomorphs are present. When lagomorphs arrive in a new environment they may become the most important resource for predators, producing an unstable equilibrium in the novel food web. Any disruption of this interaction could have catastrophic consequences for the native diversity by directly impacting predators or indirectly impacting native preys by apparent competition. Eradication or any change in their abundances should be carefully considered in conservation actions since those will have great impacts on predator populations and ultimately in the whole communities.

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Island Food Webs

Island Biogeography in the Sea of Cortés II ◽

10.1093/oso/9780195133462.003.0019 ◽

2002 ◽

Cited By ~ 1

Author(s):

Gary A. Palis ◽

Michael D. Rose

Keyword(s):

Food Web ◽

Food Webs ◽

Climatic Factors ◽

Spatial And Temporal Variability ◽

Ecological Processes ◽

Local Conditions ◽

Competitive Effects ◽

Structure And Dynamics ◽

Sea Of Cortes ◽

Secondary Productivity

Most of this book focuses on the biogeography and ecology of plants and various animal taxa on islands in the Sea of Cortés. These chapters highlight the historical and biogeographical factors that contributed to the patterns of species distribution and co-occurrence among islands. However, these patterns also reflect the action of ecological processes because the species present interact, directly or indirectly, within the food web that occurs on any given island. Island food webs may also be unique from other communities in the degree to which their structure and dynamics are also strongly influenced by the surrounding ocean. We believe that a deeper appreciation of the trophic connections between the sea and the land, and the resulting effects on the structure and dynamics of island food webs, is key to understanding the biogeography of species on islands. Many factors that operate through the food web can enhance or depress populations in a way that affects their local distribution and persistence, and, as a consequence, affects patterns of diversity on a biogeographical scale. Of these, we recognize three as being particularly important: the availability and quality of resources, competition, and consumption (i.e., by herbivores, predators, parasites). Bottom-up factors (nutrients, primary productivity, and food availability to consumers) set limits on island productivity and hence on the potential abundance of a particular group. Within a given community, secondary productivity and population density are subsequently constrained by top-down (i.e., consumption) and competitive effects. One of our goals in this chapter is to show how processes that influence productivity of gulf islands determine patterns of abundance of organisms on islands and affect interactions among species and trophic levels in these systems. Our second goal is to demonstrate the importance of spatial and temporal variability in productivity in determining the structure and dynamics of island food webs. Using our long-term studies of plants and consumers on islands in the northern gulf, we show that productivity varies greatly, both among years and islands, as a result of both local conditions and global climatic factors. Such variable productivity markedly affects food web dynamics and ultimately the abundance of species on the islands in the Sea of Cortés.

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Bird-epiphyte interactions in three Atlantic Forest environments in southeastern Brazil

Revista Brasileira de Ornitologia ◽

10.1007/bf03544454 ◽

2019 ◽

Vol 27 (2) ◽

pp. 108-114

Author(s):

Rafael Ferreira Boechat ◽

Bianca Ferreira da Silva ◽

André Felippe Nunes-Freitas

Keyword(s):

Plant Species Richness ◽

Southeastern Brazil ◽

Forest Fragments ◽

Community Interactions ◽

Ecological Processes ◽

Successional Stage ◽

Fragmented Forest ◽

High Interaction ◽

Initial Hypothesis ◽

Pasture Area

AbstractEpiphytes reach up to 67% of the total plant species richness in some tropical areas and act as diverse food resources that can be crucial in times of food scarcity. The avifauna assists in their reproduction, either through pollination or seed dispersal, thus creating a vast interaction spectrum between both communities within a continuous ecological process. Few scientific studies concerning avian and epiphytic community interactions are available and not much is known on their specific relationships. However, their absence can change existing ecological processes in habitats. With this in mind, a study undertaken at the Reserva Ecológica do Guapiaçu, Cachoeiras de Macacu, RJ analyzed bird and epiphytic interactions in three different environments: forest, fragmented forest and pastureland. The aim was to study how these interactions can vary according to their degree of conservation and successional stage. Three observation points were marked in a forest, nine points in forest fragments and ten observation points in the pastureland, thus providing a total of 1056 observation hours. As a result, 643 avian and epiphytic interactions were registered. We tested differences in the number of interactions between the areas. The initial hypothesis was that the largest number of registered interactions would occur in the preserved forest given its preserved state and existing biodiversity; however, the pasture area presented the highest number and variety of interactions. Most of the birds observed in the different habitats presented a high interaction in pasture areas where resource availability is reduced, making epiphytes an important food supply. Epiphytes permit a valuable network of interactions by attracting a high diversity of birds, especially those that disperse fruit or pollinate flowers, illustrating their importance within a degraded environment.

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Differential Responses of Food Web Properties to Opposite Assembly Rules and Species Richness

Water ◽

10.3390/w12102828 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2828

Author(s):

Yulun Guo ◽

Tao Wang ◽

García Molinos Jorge ◽

Huan Zhang ◽

Peiyu Zhang ◽

...

Keyword(s):

Food Web ◽

Food Webs ◽

A Priori ◽

Limiting Similarity ◽

Assembly Rules ◽

Scale Invariant ◽

Ecological Processes ◽

Energetic Performance ◽

Food Web Theory ◽

Specific Food

Trophic niches condition the energetic performance of species within food webs providing a vital link between food web assembly, species diversity, and functioning of ecosystems. Our understanding of this important link is, however, limited by the lack of empirical tools that can be easily applied to compare entire food webs at regional scales. By comparison, with different a priori synthetic models defined according to specific assembly rules (i.e., purely random, limiting similarity, and niche filtering), we demonstrate that a set of food web properties (trophic richness, evenness, and divergence) are controlled by ecological processes. We further demonstrate that although both limiting similarity and niche filtering are statistically significant assembly processes shaping our studied lake food webs, their relative importance is richness-dependent, and contextual to the specific food web property under consideration. Our results have both important theoretical and practical implications. Theoretically, the observed richness-dependent variation on food web properties contradicts the common criticism on food web theory that food web properties are roughly scale-invariant. Practically, these properties can help avoiding spurious conclusions, while providing useful information for multiple food web niche spaces supporting the ecosystem functioning.

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