The Holocene History of the Diatom Community in a Small Water Body on Shemya Island (Aleutian Arc, USA): The Influence of Global and Local Environmental Changes

A diatom analysis of a peat deposit from Shemya Island (Aleutian Arc, USA) is performed, and the dynamics of the diatom community are described. According to the radiocarbon dating, the formation of the deposit began 9300 cal. years BP. Principal component analysis made it possible to relate the dynamics of the diatom community to certain environmental conditions and the factors that influenced the coastal ecosystems during its formation. The following factors (predictors) were considered: the influence of age, zoo- and anthropogenic effects, and changes in climatic conditions. Sea level change was the main driver of the diatom community in the studied water body having a continuous direct and indirect influence on the studied small water body, i.e., by bird colony formation and more humid and coastal conditions. Since 3000–2000 cal. years BP, the anthropogenic factor (hunting depression of the bird colony) also became significant. During the whole water body lifetime and following peat formation, the diatom community was influenced by groups of factors: global factors (e.g., sea level rise) caused gradual change of local factors, which resulted in smooth shifts in community. In contrast, local factor influence (bird colony rise and fall due to human activity) caused abrupt and transient shifts. We can hypothesize that the relatively stable global environmental conditions in the Late Holocene were an auspicious background to see abrupt changes due to influence of the zoogenic and anthropogenic factors. We believe that further works on the material from other islands will make it possible to form a general picture of changes in the diatom communities in the Holocene and interpret it in connection with climatic changes in the region.

KOLONI BURUNG CANGAK ABU (Ardea cinerea LINNAEUS) DI AREA BANDAR UDARA INTERNASIONAL ADISUTJIPTO YOGYAKARTA (Grey Heron Colony (Ardea cinerea Linnaeus) in Yogyakarta Adisutjipto International Airport Area)

AbstrakBird strike merupakan peristiwa tabrakan antara burung baik secara berkelompok maupun tunggal dengan pesawat terbang pada proses penerbangan. Kejadian bird strike dapat menyebabkan kecelakaan ringan hingga serius yang sangat merugikan secara ekonomi Sekalipun telah dilakukan bird control secara maksimal berdasarkan panduan yang tersedia, namun bird strike juga terkadang masih terjadi di Bandar Udara Internasional Adisutjipto Yogyakarta (JOG) dengan tingkat kerusakan pesawat dari berat sampai ringan. Salah satu jenis burung penyebab kejadian bird strike di kawasan ini adalah cangak abu. Tujuan penelitian ini adalah mengetahui besaran dan prilaku koloni burung cangak abu (Ardea cinerea) pengunjung area. Pengambilan data besaran koloni burung pengunjung dilakukan dengan penghitungan langsung (sensus); perilaku selama di lokasi antara lain waktu dan arah datang dan pergi serta aktivitas yang dilakukan burung cangak abu selama di area bandara diamati dan dicatat secara langsung. Semua data yang diperoleh dianalisis secara deskriptif-kualitatif dan diperbandingkan burung lain dan hasil penelitian lain sehingga dapat diperoleh gambaran yang jelas tentang mengapa koloni cangak abu tersebut menjadi pengunjung area bandara. Hasil penelitian menunjukkan. Keberadaan burung cangak abu di Bandara Adisutjipto berpotensi relatif terbesar menimbulkan kejadian bird strike dibanding burung jenis lainnya karena jumlah individu harian yang datang terbanyak, frekuensi kedatangannya tertinggi kedua setelah burung wallet, ukuran tubuhnya yang relatif terbesar, terbang rendah, terbang pelan dan manuvernya juga lamban serta terbang menyilang landasan. Kondisi lingkungan area runway bandara yang luas, lapang terbuka, ditutupi hijauan rerumputan, berangin, aman dari predator, sepi jauh dari kegiatan manusia dan lokasinya yang strategis diantara zona roosting/nesting dan zona foraging/feeding menjadi lokasi yang ideal bagi koloni cangak abu untuk melakukan kegiatan harian loafing. Pengelola bandara JOG perlu meningkatkan kewaspadaan terhadap kemungkinan peningkatan kehadiran burung cangak abu, dan perlu memperluas jangkauan pengelolaan populasi cangak abu di luar wilayah bandara.AbstractBird strike is a bird collision event both in groups and singly with an aircraft in the flight process. Bird strike events can cause minor to serious accidents which are very detrimental to the economy. Although maximum bird control has been carried out based on the available guidelines, bird strikes also sometimes occur at Yogyakarta Adisutjipto International Airport (YAIA) with the level of aircraft damage from heavy to light. One type of bird that causes the bird strike incident at YAIA is grey heron. The purpose of this study was to determine the dayly individual number and behavior of the grey heron (Ardea cinerea), visitors to the YAIA area. Data collection on visitor bird colony size is carried out by direct count (census); behavior while in YAIA, including the time and direction of coming and going, and what the grey heron did during the airport area was observed and recorded directly. All data obtained were analyzed descriptively-qualitatively and compared to other birds and other research results so that a clear picture of why the colony of grey heron can be obtained as a visitor to the YAIA area. The results showed. the presence of grey heron (Ardea cinerea) at Adisutjipto Airport has the highest relative potential to cause bird strike events compared to other types of birds because the highest number of daily individuals, the second highest frequency of arrival after a glossy swiftlet, the largest relative body size, low flight, slow flight and maneuvers are also slow and fly across the runway. The YAIA runway area, which is wide, open and covered with grasses, windy, safe from predators, is quiet away from human activities and a strategic location between the roosting / nesting zone and the foraging / feeding zone makes it an ideal location for grey heron colonies to conduct colony of grey heron daily loafing activities. In conclusion, the manager of YAIA needs to increase awareness of the possibility of increasing the presence of grey herons, and it is necessary to broaden the scope of management of the grey heron population outside the YAIA region.

Effects of sea birds and soil development on plant and soil nutritional parameters after 50 years of succession on Surtsey

Surtsey, the island that rose from the sea in a submarine eruption during 1963 to 1967, has been the subject of many studies on primary succession. These studies have intensified after the establishment of a seagull colony on the island in 1986. This paper reports on the results of a short sampling expedition in 2013 that intended to characterize the interactive effects of the seagull colony and of soil development on soil nutritional characteristics in the tephra sands that cover the underlying lava, as well as in plants growing inside and outside the seagull colony. Feces and pellets of the gulls were extremely rich in both nitrogen (N) and phosphorus (P) and δ15N analyses showed that N was transferred from pellets and feces to the tephra soils and subsequently taken up by the plants. The tephra soils not affected by the birds showed a high concentration of P compared to N. The concentration of both nutrients was much lower than in the soils of the bird colony. In general, variation in tephra soil depth had little effect on nutritional characteristics, except for the very low N concentration in deep soils. Thus, our results confirm the overriding effect of the seagull colony on Surtsey on nutritional characteristics of the developing soils and vegetation. Due to the very high P availability of the volcanic soils in combination with the high P input by the birds, vegetation productivity is N limited, despite the extremely high N input of 47 kg N ha-1 yr-1 that the birds add to the system. Our findings emphasize the extreme importance of bird colonies on the nutritional ecology of young, N-poor ecosystems.

Wanted dead or alive: a state-space mark–recapture–recovery model incorporating multiple recovery types and state uncertainty

We developed a state-space mark–recapture–recovery model that incorporates multiple recovery types and state uncertainty to estimate survival of an anadromous fish species. We apply the model to a dataset of outmigrating juvenile steelhead trout (Oncorhynchus mykiss (Walbaum, 1792)) tagged with passive integrated transponders, recaptured during outmigration, and recovered on bird colonies in the Columbia River basin (2008–2014). Recoveries on bird colonies are often ignored in survival studies because the river reach of mortality is often unknown, which we model as a form of state uncertainty. Median outmigration survival from release to the lower river (river kilometre 729 to 75) ranged from 0.27 to 0.35, depending on year. Recovery probabilities were frequently ≥0.20 in the first river reach following tagging, indicating that one out of five fish that died in that reach was recovered on a bird colony. Integrating dead recovery data provided increased parameter precision, estimation of where birds consumed fish, and survival estimates across larger spatial scales. More generally, these modeling approaches provide a flexible framework to integrate multiple sources of tag recovery data into mark–recapture studies.

Impact of the bird-manure caused eutrophication on the abundance and diversity of chironomid larvae (Diptera; Chironomidae) in lakes of the Bolshoy Aynov Island (Russia, Barents Sea)

We report on the perceived impact of bird faeces as an agent of organic matter transfer on the density and species richness of the Chironomidae in the lakes of the Bolshoy Aynov island (Barents Sea, Northern Russia). In total we recorded 15 species of Chironomidae. Highest species richness and specimen numbers were recorded in Lake Severnoe, closest to the large bird colony.

Long-term decline in breeding abundance of Black-headed Gull (Chroicocephalus ridibundus) in the Czech Republic: a case study of a population trend at the Chomoutov lake

The aim of this paper is to evaluate the long-term trend in breeding abundance of Black-headed Gull (Chroicocephalus ridibundus) at the Chomoutov lake, Czech Republic. In the period 1978-2014 (always between April 22 and May 10), we conducted 14 nest counts in the bird colony using the direct nest search method. In total, we counted 57,860 nests, from which 2,174 nests were found in the initial year 1978, the maximum number of nests (8,371) in 1993 and 3,304 nests in the last counting year 2014. The nests were located on the ground on an island elevated 2-3 m above the water level. In 1997, we found an unusually located nest on a nesting pad in a poplar tree (Populus sp.), 821 cm above the water level. In this paper, we point out the long-term decline in breeding abundance of Black-headed Gull in major breeding colonies in the Czech Republic, where the abundance declined by up to 95%, while numerous colonies have vanished completely. We discuss factors influencing the negative population trend of Black-headed Gull on the monitored site and in the entire Czech Republic.

Decline in breeding of the Great Black-backed Gull, Larus marinus, and the Herring Gull, L. argentatus, on Boot Island, Nova Scotia, 1986 to 2010

For over 50 years, Boot Island, Nova Scotia, has supported a significant mixed bird colony: Great Black-backed Gull (Larus marinus), Herring Gull (L. argentatus), Great Blue Heron (Ardea herodias), and Double-crested Cormorant (Phalacrocorax auritus). In 2002, the largest Great Black-backed Gull colony in Canada was located there. Over the last quarter century, the Herring Gull colony has shown a dramatic and near-linear decrease from 727 nests in 1986 to 67 in 2000; in 2010, only two nests remained. The number of Great Black-backed Gull nests has also declined by 44%, from 1467 nests in 1992 to 819 in 2010. These reductions may be partly attributed to factors external to the colony, such as changes in regional fisheries and better landfill management. However, a more immediate problem may be nest predation and disturbance by American Mink (Neovison vison), Raccoon (Procyon lotor), Coyote (Canis latrans), and Bald Eagle (Haliaeetus leucocephalus).