Browsing by Subject "Threatened species"

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  • Poysa, Hannu; Lammi, Esa; Poysa, Silvo; Vaananen, Veli-Matti (2019)
    Interactions and dependence between species can transmit the effects of species declines within and between trophic levels, resulting in secondary endangerments and, in some cases, extinctions. Many mixed-species avian breeding aggregations commonly have a protector species whose aggressive nest defense is used by other species to defend their nests. Disappearance of the protector species may have population demographic consequences on the dependent species. Aggressive nest defense behavior of small colonial gulls, such as the black-headed gull (Chroicocephalus ridibundus), is used by many waterbird species to gain protection against predators. We used data from 15 local waterbird communities in Finland to study long-term changes and dynamics of breeding numbers of other waterbirds as a response to long-term changes and dynamics of black-headed gull colonies. We found that breeding numbers of many species tracked long-term changes in the size of black-headed gull colonies. This was true even after controlling for a common trend in the size of the black-headed gull colony and the breeding numbers of the other species. The trend-controlled positive temporal association with black-headed gull was relatively stronger in species that nest in similar habitats of a lake as the black-headed gull, and in species that have a more critical conservation status due to drastic population decline. Our results suggest that the overall decline of black-headed gull colonies has resulted in secondary endangerment of many other species in waterbird communities.
  • Cardoso, Pedro; Barton, Philip S.; Birkhofer, Klaus; Chichorro, Filipe; Deacon, Charl; Fartmann, Thomas; Fukushima, Caroline S.; Gaigher, René; Habel, Jan C.; Hallmann, Caspar A.; Hill, Matthew J.; Hochkirch, Axel; Kwak, Mackenzie L.; Mammola, Stefano; Ari Noriega, Jorge; Orfinger, Alexander B.; Pedraza, Fernando; Pryke, James S.; Roque, Fabio O.; Settele, Josef; Simaika, John P.; Stork, Nigel E.; Suhling, Frank; Vorster, Carlien; Samways, Michael J. (2020)
    Here we build on the manifesto ‘World Scientists’ Warning to Humanity, issued by the Alliance of World Scientists. As a group of conservation biologists deeply concerned about the decline of insect populations, we here review what we know about the drivers of insect extinctions, their consequences, and how extinctions can negatively impact humanity. We are causing insect extinctions by driving habitat loss, degradation, and fragmentation, use of polluting and harmful substances, the spread of invasive species, global climate change, direct overexploitation, and co-extinction of species dependent on other species. With insect extinctions, we lose much more than species. We lose abundance and biomass of insects, diversity across space and time with consequent homogenization, large parts of the tree of life, unique ecological functions and traits, and fundamental parts of extensive networks of biotic interactions. Such losses lead to the decline of key ecosystem services on which humanity depends. From pollination and decomposition, to being resources for new medicines, habitat quality indication and many others, insects provide essential and irreplaceable services. We appeal for urgent action to close key knowledge gaps and curb insect extinctions. An investment in research programs that generate local, regional and global strategies that counter this trend is essential. Solutions are available and implementable, but urgent action is needed now to match our intentions.
  • Hällfors, Maria; Lehvävirta, Susanna; Aandahl, Tone; Lehtimäki, Iida-Maria; Nilsson, Lars Ola; Ruotsalainen, Anna; Schulman, Leif E.; Hyvärinen, Marko T. (2020)
    Ongoing anthropogenic climate change alters the local climatic conditions to which species may be adapted. Information on species' climatic requirements and their intraspecific variation is necessary for predicting the effects of climate change on biodiversity. We used a climatic gradient to test whether populations of two allopatric varieties of an arctic seashore herb (Primula nutans ssp.finmarchica) show adaptation to their local climates and how a future warmer climate may affect them. Our experimental set-up combined a reciprocal translocation within the distribution range of the species with an experiment testing the performance of the sampled populations in warmer climatic conditions south of their range. We monitored survival, size, and flowering over four growing seasons as measures of performance and, thus, proxies of fitness. We found that both varieties performed better in experimental gardens towards the north. Interestingly, highest up in the north, the southern variety outperformed the northern one. Supported by weather data, this suggests that the climatic optima of both varieties have moved at least partly outside their current range. Further warming would make the current environments of both varieties even less suitable. We conclude that Primula nutans ssp. finmarchica is already suffering from adaptational lag due to climate change, and that further warming may increase this maladaptation, especially for the northern variety. The study also highlights that it is not sufficient to run only reciprocal translocation experiments. Climate change is already shifting the optimum conditions for many species and adaptation needs also to be tested outside the current range of the focal taxon in order to include both historic conditions and future conditions.