Compared distribution within a disturbed fishpond ecosystem of breeding ducks and bird species indicators of habitat quality

Abstract

The distribution of breeding ducks versus three other bird species (Mute Swan Cygnus olor, Black-headed Gull Larus ridibundus and Purple Heron Ardea purpurea) among waterbodies was investigated in the Dombes area, Eastern France, where breeding duck populations have undergone a severe decline following a large-scale transformation of meadow habitat into cropland. Higher Pochard Aythya ferina, Tufted Duck Aythya fuligula, Redcrested Pochard Netta rufina and Gadwall Anas strepera pair densities were recorded in fishponds where Blackheaded Gulls were nesting. In these ponds however, nesting success (assessed by the number of broods divided by the number of pairs) was not significantly higher. Similarly, Pochard pair density was higher in ponds with a Purple Heron colony, but brood densities were not. We hypothesise that, in the study region, clutch concentration in the most attractive areas could compensate for the anti-predation effect of gull colonies or overwater nesting in shore vegetation. We could not confirm the expected negative impact of Mute Swan aggressive behaviour on duck distribution. Even though Mallard Anas platyrhynchos pair density was lower in ponds with breeding swans, we did not observe difference for Mallard broods. Moreover, Redcrested Pochard pair density and nesting success were higher in ponds where swans were breeding, probably as a consequence of shared habitat preferences.

Temporal variation in pond use and breeding success for ducks in French fishpond regions: on possible consequences of a decline in fish farming

“…Stable brood: pair ratio in Forez contrasted with a decrease recorded in Dombes and in Brenne, which could correspond either to a lower proportion of adults actually nesting, or to higher losses before or immediately after hatching. Such a negative trend could be hypothetically related to the arrival and the expansion of the Coypu, with correlative impacts on helophyte stands and reduction in available areas of nesting habitat (Curtet et al, 2008), thereby increasing the risk of clutch predation (Broyer, 2009). Under that hypothesis however, it would be difficult to explain the absence of negative effect on the brood: pair ratio in Forez despite the increased density of recorded pairs.…”

“…In each region, pond surroundings are made up mainly by croplands or grasslands, more intensively managed in Dombes where a massive conversion of grasslands to cereal crops since the 1970s had severely affected duck breeding conditions (Tournier, 1990;Broyer, 2000). This reduction in meadow habitats in Dombes may have led to nest concentration in aquatic vegetation and increased impacts of nest predators (Broyer, 2009). The game harvest at the opening of the hunting season probably impinges on local production.…”

Measuring habitat quality for waterbirds: A review

“…For example, the abundance of gulls ( Larus spp.) was correlated with better waterbird brood success, probably because gulls provided defense against predators (Arzel et al, 2015 ; but see Broyer ( 2009 ) where no such effect of gulls was found). However, facilitative interactions will not occur in all species pairings and some interactions will have a negative impact on habitat quality for one species, such as aggression by Mute Swans ( Cygnus olor ) leading to a reduction in breeding pair density of Mallards ( Anas platyrhynchos ; Broyer, 2009 ).…”

Short Communication: Trees species diversity and indicator species in Bedugul forest ecosystem, Bali, Indonesia

“…There were also 4 species in the forest of Bukit Lesung, namely Lophopetalum javanicum, Syzygium racemosum, Dysoxylum nutans and Dendrocnide peltata Table 4. Indicator species has been used in many ecological research, however mostly these are in a form of animal species or microorganism, moreover these indicators usually refers to a species in degraded or disturbed habitat (Bachand et al 2014;Broyer 2009;Newton and Horner 2003). Plant species can also be used as indicators.…”