Disturbance Ecology

Understory avian insectivores are especially sensitive to deforestation, although regional differences in how these species respond to human disturbance may be linked to varying land-use histories. South Asia experienced widespread conversion of forest to agriculture in the nineteenth century, providing a comparison to tropical areas deforested more recently. In Sri Lanka and the Western Ghats of India, we compared understory insectivores to other guilds, and to insectivores with different vertical strata preferences, both inside mixed-species flocks and for the whole bird community. Overall species richness did not change across the land-use gradient, although there was substantial turnover in species composition between land-use types. We found that the proportion of species represented by insectivores was ~1.14 times higher in forest compared to agriculture, and the proportion of insectivores represented by understory species was ~1.32 times higher in forests. Mass-abundance rela...

The overall objectives of the study were to assess the current status of the Sal Forests in the Rangpur Division of Bangladesh. The study also aimed to identify the major forms of human disturbance, to assess the effects of disturbance on biodiversity and to recommend sustainable management strategies. It was found that the remnants are primarily concentrated in areas like Mithapukur Upazila of Rangpur district. In the Naogaon district, a few patches still occur in Paikbhanda, Dhamouirhat and Patnitolla along the western border of the country. There is no Sal stands Patnitolla, which was converted into exotic woodlots. The Shorea robusta was the dominant tree species in the other remnants. Illegal logging, agricultural encroachment, and insect infestations were identified as existential threats to biodiversity. In the core and buffer zones of each forest, natural regeneration should be facilitated to maintain the ecological balance and to ensure continuous forest coverage. In addition, direct seeding in the buffer zone and degraded forest areas can improve the naturalness. Advanced regeneration of rare or endangered species can protect the species from extinction. Very fast-growing and timbering native species should be planted in the encroached areas.

Since its emergence, the contemporary environmental problem has become an object of analysis and intervention both for ecology (area of biology) and for different intergovernmental organizations with a global reach. In both fields, a series of conceptual frameworks have been developed aimed at addressing ecological changes, that is, those alterations that affect units that are the object of study of ecology. The aim of this paper is to clarify and contrast the ways in which disturbance ecology (a recent field within ecology) and different intergovernmental organizations conceptualize and approach ecological change. To do this, we make an analytical comparison between the ecological concept of 'disturbance' and the notion of 'driver' coming from intergovernmental organizations. In the comparison, we observe that these concepts seek to explain similar processes of ecological change under the same causal logic, although they show important differences in the treatment of the initial conditions that allow them to be studied. We conclude that the notion of 'driver' leads to an epistemological impoverishment in relation to the concept of 'disturbance'. Finally, we discuss some implications of this epistemological problem, given that it is the impoverished notion of 'driver' that is imposed on the international context when explaining an ecological change, and materialized in guidelines which are recognized by nations around the world. Thus, this impoverishment is transferred to the field of public policy. It is urgent to rethink to

The overall objectives of the study were to assess the current status of the Sal Forests in the Rangpur Division of Bangladesh. The study also aimed to identify the major forms of human disturbance, to assess the effects of disturbance on biodiversity and to recommend sustainable management strategies. It was found that the remnants are primarily concentrated in areas like Mithapukur Upazila of Rangpur district. In the Naogaon district, a few patches still occur in Paikbhanda, Dhamouirhat and Patnitolla along the western border of the country. There is no Sal stands Patnitolla, which was converted into exotic woodlots. The Shorea robusta was the dominant tree species in the other remnants. Illegal logging, agricultural encroachment, and insect infestations were identified as existential threats to biodiversity. In the core and buffer zones of each forest natural regeneration should be facilitated to maintain the ecological balance and to ensure continuous forest coverage. In addition, direct seeding in the buffer zone and degraded forest areas can improve the naturalness. Advanced regeneration of rare or endangered species can protect the species from extinction. Very fast-growing and timbering native species should be planted in the encroached areas.

The overall objectives of the study were to identify the major forms of human disturbance in the Cumilla Sal forests; to assess the effects of disturbance on biodiversity and forest structure; and to recommend conservation and sustainable management strategies. The study revealed that Shorea robusta was the primary tree species in the fragmented remnants, accompanied by Careya arborea, Bauhinia spp., and Holarrhena pubescens. The family Leguminosae was the highest in species count, followed by Euphorbiaceae and Rubiaceae. Illegal Logging, Agricultural Encroachment, Fuel wood collection, grazing pressure, road construction, settlement expansion, monoculture, resource dependency, commercial pressures and insect infestations were identified as existential threats to biodiversity. Sustainable forest management, community participation, and conservation policies are essential for protecting these remaining Sal forest ecosystems in Bangladesh. Moving away from top-down bureaucratic approaches toward more people-centric models is highly warranted.

Understanding forest development following the cessation of management remains a key challenge in forest ecology. Gap dynamics, a driver of structural and compositional change, might serve as an important indicator of progression toward old-growth conditions. This study investigates and compares the long-term gap dynamics of two Central European forest reserves (Kékes-old-growth and Őserdőlong untouched) dominated by European beech (Fagus sylvatica L.) over a 42-45-year period, using aerial imagery. Our aim was to assess how historical management legacies influence gap size, formation, persistence, and closure, and to evaluate these processes relative to the forests' naturalness levels. Gap fractions ranged between 4.9%-9.9% in Kékes and 2.3%-10.7% in Őserdő. These values are mostly consistent with previous reports for primary European beech forests. In Kékes, smaller gaps (<200 m 2) predominated, while in Őserdő, following a sequence of recent disturbances, gaps of 200-499 m 2 became dominant. Statistical analyses revealed a significantly steeper increase in total gap area in Őserdő, reflecting greater sensitivity to exogenous disturbances, likely due to its more homogeneous stand structure and residual management effects. Site conditions, browsing pressure, and topography might have further contributed to the observed divergence. Our results indicate that the fine-scale endogenous dynamics, typical of old-growth forests (characterized by small, recurring gaps of endogenous processes), develop only several decades after the last human intervention. The study highlights that gap dynamics might serve as an indicator of forest naturalness and can guide restoration planning. Promoting structural heterogeneity and mimicking natural gap processes may accelerate recovery toward old-growth characteristics in formerly managed forests.

Munkánk során a 2014-ben bekövetkezett -az elmúlt 50 év legnagyobb kiterjedésű és intenzitású -jégtörésének hatásait vizsgáltuk a Börzsönyben. Elvégeztük a jégtörés egyes tulajdonságainak kvantitatív leírását és összehasonlítottuk a korábbi börzsönyi jégtörésekkel kapcsolatos kutatások eredményeivel.A jégtörés előtt felmért területek újrafelvételezésével (azonos módszertan alapján) lehetőség nyílt a jégtörés hatásainak kimutatására. A 885 db mintavételi pont elemzése alapján megállapítható, hogy a jégtörés a nitrofil lágyszárúak tömeges felszaporodását, illetve az alacsony (< 50 cm) újulat borításának növekedését váltotta ki. E változások mértékét befolyásolhatja, hogy megtörtént-e a kidőlt faanyag összetermelése, s ha igen milyen technikával. Az erdészeti gépek által okozott talajbolygatás jobban károsítja az újulatot és nagyobb nitrofil borítást eredményez, mint a tradicionális közelítési technikák (lovas, kézi). Az erdőgazdálkodás alól több évtizede kivont Pogány-Rózsás Erdőrezervátum területén az erdők a gazdaságiakhoz képest kevésbé károsodtak. Kulcsszavak: bolygatásjelző lágyszárúak, erdőrezervátum, Fagus sylvatica, jégkár, közelítés, nitrofil lágyszárúak, természetes bolygatás, természetközeli erdőgazdálkodás In the last decades, natural disturbances have caused increasing damages in European forests. In 2014, catastrophic ice damage (the worst in 50 years) occurred in the Börzsöny Mts., Hungary. In our study, we made a quantitative description and comparison of ice disturbance events of the last 20 yrs. in the Börzsöny Mts. We also examined the effects of the 2014's ice disturbance: we resampled 885 sampling points with the same methodology which was used before the ice break. Our results showed that the decrease in canopy closure resulted in increased cover of nitrophilic herbaceous plants and low (below 0.5 m) tree regeneration. We also showed that the salvage logging (and the applied techniques) have an impact on the mentioned cover changes. Compared with traditional logging techniques (horse or human powered), logging with machines could generate more severe damage in the saplings, and could contribute to the increase in the cover of nitrophilic herbs. In the Pogány-Rózsás Forest Reserve (which has been unmanaged for some decades) compared with the managed forests, had slightly less serious effects of the ice break.

Abstract
Background and Aims
Grasslands in the Terai–Duar Savanna and Grasslands ecoregion, located at the base of the Himalayas, are disturbance-dependent ecosystems where grassland loss attributable to woody encroachment has been reported in recent decades. Although some of this loss is offset by grassland emergence, the extent and drivers of grassland expansion remain poorly understood. Here, we aim to study the relationship between grassland emergence, ecosystem characteristics and disturbance factors.

Methods
We analysed satellite-based land-cover classifications (Landsat TM/OLI) from 1988 to 2019 across eight protected areas (four in each of India and Nepal) to quantify grassland emergence starting from non-grassland land cover. We applied a two-tiered Bayesian modelling framework: (1) a landscape-scale mixed-effects binomial model (with protected area as a random effect) to identify environmental drivers; and (2) site-specific spatial regression models with conditional autoregressive priors to capture local patterns while accounting for spatial autocorrelation.

Key Results
Over the last three decades, grassland emergence was observed in 9.5 % of the non-grassland area, which accounts for ∼37 % of the current grassland extent. Grassland emergence was favoured in sites with steep slopes, high soil moisture content (as indicated by the topographic wetness index) and frequent fire, but inhibited at higher elevations and greater distances from human settlements or water bodies. The importance of environmental drivers varied by site, and the effects of fire were strongest in high-rainfall sites, whereas topographic and hydrological factors dominated in the drier sites. Greater grassland formation near human settlements suggests that anthropogenic disturbance (mainly livestock grazing and fires) can mimic natural processes in creating open habitats.

Conclusions
These findings underscore the ecological significance of disturbance regimes (flood, human influence and fire) in maintaining grasslands and habitat management for conservation.

Antecedentes y Objetivos: El estado de Veracruz ha sido estudiado desde el punto de vista botánico desde finales del siglo XVI. No obstante, aún quedan
zonas poco exploradas de su territorio. De esta forma, el objetivo de la presente investigación fue recopilar y generar conocimiento más completo
y actual sobre la flora y vegetación del Parque Nacional Cañón del Río Blanco (PNCRB), en el centro de Veracruz, México.
Métodos: A través de recorridos de campo durante dos periodos (2012-2014 y 2016) se realizaron colectas botánicas y observaciones, lo cual se complementó con una revisión bibliográfica, de herbario y de bases de datos de herbarios. Se elaboró un mapa de vegetación y una recopilación de información sobre la riqueza florística del PNCRB.
Resultados clave: Se registraron seis tipos de vegetación; se presenta el mapa de uso de suelo y vegetación del área de estudio y se obtuvo una lista
florística de 2062 especies en el territorio del PNCRB. De ellas, 93 son especies bajo alguna categoría de riesgo, dos representaron nuevos registros para el estado de Veracruz, 373 son especies endémicas y 145 cuasiendémicas de México.
Conclusiones: El PNCRB aun resguarda tipos de vegetación con una importante riqueza florística. Al comparar esta característica con la de áreas naturales protegidas cercanas, se enfatiza la importancia de este Parque Nacional.

Bark beetles cause extensive tree mortality in coniferous forests of western North America and play an important role in the disturbance ecology of these ecosystems. Recently, elevated populations of bark beetles have been observed in all conifer forest types across the western United States. This has heightened public awareness of the issue and triggered legislation for increased funding for state and federal agencies to address issues associated with bark beetle outbreaks. Recently, US Forest Service, Research and Development entomologists from the western research stations met with US Forest Service, State and Private Forestry, Forest Health Protection entomologists, our primary stakeholder, to identify bark beetle research priorities. These include vegetation management; ecological, economic, and social consequences of outbreaks; fire and bark beetle interactions; effects of climate change on bark beetle populations; and chemical ecology.

A study of the application of satellite images to the identification of vegetation in a small area corresponding to the arid zone of Veracruz and part of Puebla is presented. This study is accomplished by means of images from the LANDSAT satellite obtained on January 19 and May 23, 1973. The interpretation of the different maps is made on the basis of information from the data bank of the Flora de Veracruz program, and various surveys made by land and air.

Urbanization modifies natural landscapes but also generates new habitats for adaptable species, such as some birds. We compared the avian diversity between winter 2006 and 2024 in two urban parks of Osorno, southern Chile: Chuyaca Park and IV Centenario Park. We measured the avian diversity along 100 × 30 m strip transects in three habitats: riparian, grassland, and forest. We detected an increase in species richness from 3 to 8 in 2006 to 6-10 in 2024. Ubiquitous species, such as Southern Lapwing (Vanellus chilensis) and Chimango Caracara (Milvago chimango), remained numerically constant. The Horn index indicated greater similarity in the Chuyaca riparian (0.811) and intermediate similarity in the IV Centenario forest (0.59). These results highlight the role of urban riverbanks as key habitats for birdlife and the importance of urban parks as conservation spaces in intermediate-sized cities.

The starting point of this article is the assumption that the “barrier effect” in applied ecology is undisputable and exceptional, because in both human and ecological dimen-sions it constitutes the “causal” and the “nexus”. As regards the human dimension the causative factors are lack of vertical cooperation between scientists and practitioners, as well as polarisation of practitioners’ viewpoints, which leads to neglected horizon-tal relationships. The “humane” nexus arises not only during the law-making stage but also during administrative procedures authorising plans or projects affecting the en-vironment (SEA and EIA procedures). It manifests first in documentary evidence: mul-tiplying advanced analyses, often mediated by computer-model abstractions, creates a time load for public administration. As regards ecological dimension the causative factor results from infrastructural development. The “nexus” concerns fragmentation and loss of habitats, as well as increased mortality rates of specimens during migration routes. Anchored in Land’s remit at the interface of landscape ecology and land-use governance, the authors intend to prove that “applied ecology” should be understood as a “joint venture agreement” between all entities undertaking education, research and exchange of knowledge to restore sustainable ecological phenomena, and to open discussion on transboundary impact assessments of wind-farm developments as re-gards bird migration.

Fire is one of the main disturbance agents globally and one of the main threats on the Brazilian cerrado (Neotropical savanna), acting as environmental filter for species selection. Individuals of Morpho helenor achillides (C. Felder and R. Felder, 1867) and M. menelaus coeruleus (Perry, 1810) were captured weekly using entomological nets and fruit-baited traps over a 36-mo period (from May 2005 to April 2008). The present study analyzed the impact of a fire event in both the above species, showing that they present different responses to this disturbance. Morpho helenor was persistent as adults during the dry season, which could fly away from the flames to neighbor unburned areas and return after dry-season bushfires. Conversely, Morpho menelaus persists only as caterpillars during the dry season, which are unable to escape from the flames resulting in high impacts on local population (the species was not captured up to the end of this study). In addition, based on host plant speci...

The use of drones for monitoring nesting birds is rapidly increasing given their affordability and efficiency in bird detection and quantification across habitats. Reports of disturbance caused by drones on different bird species have been mixed, with no consensus on the degree to which different factors affect disturbance responses. Given the lack of systematic assessments of disturbance from drones on nesting birds, we conducted a formal meta-analysis to quantify the degree of disturbance caused by multi-rotor drones on nesting birds, with a particular focus on the effects of altitude of flights and species nesting traits. Seventeen studies met our criteria for inclusion in the analysis, from which we extracted 31 effect sizes in the form of log-odds ratio. Drones showed a small disturbance effect (-1.54; 95% CI:-2.83,-0.26) on nesting birds overall, but heterogeneity was large. Drone flights > 50 m showed no evidence of disturbance on nesting birds. Conversely, flights at lower altitudes (≤ 50 m) showed stronger evidence of disturbance effects, with the largest odds of disturbance observed on ground solitary and non-ground solitary nesters. Only ground colonial nesters showed no evidence of disturbance regardless of the drone altitude. We conclude that the use of drones can be an efficient and safe means of surveying nesting birds if altitude and nesting traits are considered in survey protocols. RESUMEN. El uso de drones para monitorear las aves que anidan está aumentando rápidamente dada su asequibilidad y eficiencia en la detección y cuantificación de aves en todos los hábitats. Los informes de perturbaciones causadas por drones en diferentes especies de aves han sido mixtos, sin consenso sobre el grado en que los diferentes factores afectan las respuestas de perturbación. Dada la falta de evaluaciones sistemáticas de la perturbación de los drones en las aves que anidan, realizamos un metanálisis formal para cuantificar el grado de perturbación causada por drones multirotor en las aves que anidan, haciendo foco en particular en los efectos de la altitud de los vuelos y los rasgos de anidación de las especies. Diecisiete estudios cumplieron los criterios de inclusión en el análisis, de los cuales se extrajeron 31 tamaños del efecto en forma de relación logarítmica de probabilidades. Los drones mostraron un pequeño efecto de perturbación (-1,54; IC del 95%:-2,83,-0,26) en las aves que anidan en general, pero la heterogeneidad fue grande. Los vuelos de drones > 50 m no mostraron evidencia de perturbación en las aves que anidan. Por el contrario, los vuelos a altitudes más bajas (≤ 50 m) mostraron una mayor evidencia de efectos de perturbación, con las mayores probabilidades de perturbación observadas en anidadores solitarios y no terrestres. Solo los anidadores coloniales terrestres no mostraron evidencia de perturbación, independientemente de la altitud del dron. Concluimos que el uso de drones puede ser un medio eficiente y seguro para inspeccionar las aves que anidan si la altitud y los rasgos de anidación se consideran en los protocolos de monitoreo.