Tūhoe Tuawhenua mātauranga of kererū (

Indigenous peoples? knowledge on changes in wildlife populations and explanations for these changes can inform current conservation and wildlife management systems. In this study, Tūhoe Tuawhenua interviewees provided mātauranga (traditional knowledge) about a repertoire of visual (e.g. decreasing flock size), audible (e.g. less noise from kererū in the forest canopy), and harvest-related (e.g. steep decline in harvests since the 1950) indicators used to assess kererū (New Zealand pigeon; Hemiphaga novaeseelandiae novaeseelandiae) abundance and condition in Te Urewera, New Zealand over the last 100 years. Metaphorical explanations for the decline in kererū included the loss of mana (authority and prestige) by the iwi (tribe) over the kererū and forest, and the retraction of the kererū?s mauri (life force) by Tāne Mahuta (God of the Forest). Interviewees reported that predation and interspecific competition with introduced species, variability in food supply, and loss of habitat were the principal biophysical mechanisms to have caused declines in kererū abundance. Long-term qualitative monitoring by Tūhoe Tuawhenua has the potential to guide the restoration of kererū and wider environmental management in Te Urewera. Allowing iwi the self-determination to make management decisions according to their mātauranga (or science, if desired) is likely to lead to greater application of results and altered practices where required for sustainability.     

Long-term patterns of fruit production in five forest types of the South Carolina upper coastal plain

Fleshy fruit is a key food resource for many vertebrates and may be particularly important energy source to birds during fall migration and winter. Hence, land managers should know how fruit availability varies among forest types, seasons, and years. We quantified fleshy fruit abundance monthly for 9 years (1995–2003) in 56 0.1-ha plots in 5 forest types of South Carolina's upper Coastal Plain, USA. Forest types were mature upland hardwood and bottomland hardwood forest, mature closed-canopy loblolly (Pinus taeda) and longleaf pine (P. palustris) plantation, and recent clearcut regeneration harvests planted with longleaf pine seedlings. Mean annual number of fruits and dry fruit pulp mass were highest in regeneration harvests (264,592 ± 37,444 fruits; 12,009 ± 2,392 g/ha), upland hardwoods (60,769 ± 7,667 fruits; 5,079 ± 529 g/ha), and bottomland hardwoods (65,614 ± 8,351 fruits; 4,621 ± 677 g/ha), and lowest in longleaf pine (44,104 ± 8,301 fruits; 4,102 ± 877 g/ha) and loblolly (39,532 ± 5,034 fruits; 3,261 ± 492 g/ha) plantations. Fruit production was initially high in regeneration harvests and declined with stand development and canopy closure (1995–2003). Fruit availability was highest June–September and lowest in April. More species of fruit-producing plants occurred in upland hardwoods, bottomland hardwoods, and regeneration harvests than in loblolly and longleaf pine plantations. Several species produced fruit only in 1 or 2 forest types. In sum, fruit availability varied temporally and spatially because of differences in species composition among forest types and age classes, patchy distributions of fruiting plants both within and among forest types, fruiting phenology, high inter-annual variation in fruit crop size by some dominant fruit-producing species, and the dynamic process of disturbance-adapted species colonization and decline, or recovery in recently harvested stands. Land managers could enhance fruit availability for wildlife by creating and maintaining diverse forest types and age classes. © 2012 The Wildlife Society.     

High flexibility in diet and ranging patterns in two golden monkey (Cercopithecus mitis kandti) populations in Rwanda

Many primates exhibit behavioral flexibility which allows them to adapt to environmental change and different habitat types. The golden monkey (Cercopithecus mitis kandti) is a little-studied endangered primate subspecies endemic to the Virunga massif and the Gishwati forest in central Africa. In the Virunga massif, golden monkeys are mainly found in the bamboo forest, while in the Gishwati forest they live in mixed tropical montane forest. Here we describe and compare the diet of golden monkeys in both fragments. Over 24 consecutive months from January 2017 we used scan sampling to record feeding and ranging behavior of two Virunga groups and one Gishwati group totaling ca. 240 individuals. We also examined the phenology of bamboo and fruit trees, key seasonal food plant species for the monkeys. Golden monkeys fed on more than 100 plant species. The Virunga groups were mostly folivorous (between 72.8% and 87.16% of the diet) and fed mostly on young bamboo leaves and bamboo shoots, while 48.69% of the diet of the Gishwati group consisted of fruit from 22 different tree and shrub species. Bamboo shoots and fruit are seasonally available foods and were consumed regularly throughout the period when they were available. Despite being the smallest of the three study groups, the Gishwati group had a larger home range area (150.07 ha) compared to both Virunga groups (25.24 and 91.3 ha), likely driven by the differences in availability and distribution of fruit and bamboo in the habitats. Like other blue monkey subspecies, golden monkeys appear to have a flexible dietary strategy enabling them to adjust diet and ranging behavior to local habitats and available food resources. Additional studies and continuing conservation efforts are needed to better understand how variation in feeding and ranging ecology affects reproduction, population growth, and carrying capacity.     

Ranging Patterns of Chimpanzees in a Montane Forest of Kahuzi,Democratic Republic of Congo

I studied ranging patterns of a semihabituated unit-group of chimpanzees for 60 mo at Kahuzi. They had a total home range of 12.81 km² and a mean annual home range of 7.55 km². Considering the low density of chimpanzees in the area vis-à-vis chimpanzees in arid areas, their home range is very small. Kahuzi chimpanzees used the home range in a clumped pattern, frequently visiting the core area and only rarely entering peripheral areas. The monthly range changes with fruit availability, increasing during periods of fruit scarcity. There was no consistent seasonal difference in the size of the home range. However, use of different habitat types may vary seasonally. While there was no seasonal effect in the use of primary forest, the chimpanzees showed a statistically consistent seasonal difference in their use of secondary forest, visiting it mainly during the dry season when fig trees were in fruit. Since the primary forest provides them with more food fruits, chimpanzees tended to use more frequently the small patches of primary forest in their home range. Thus, the size and distribution of small fragmented primary forests may be an important factor influencing the ranging pattern of chimpanzees at Kahuzi.     

Diet of the opossum Trichosuvus vulpecula (Kerr) in the Orongorongo Valley,Wellington, New Zealand,in relation to food‐plant availability

The food preferences of a population of opossums in 4.4 ha of lowland broadleaf/podocarp forest were studied for 4 years by faecal analysis. A survey and phenological records were made of the vegetation to compare foods eaten with foods available. Metrosideros robusta and Weinmannia racemosa contributed 60% to the leaf diet, and were being defoliated and killed by opossums. Metrosideros fulgens and Ripogonum scandens, both lianes, together contributed 15 % to the leaf diet but were eaten seasonally. About 10 other species contributed small amounts. Flowers, flower buds, fruit, seeds, bark, and petiole made up about 35 % of the total diet. Compared with their status in the same area 30 years ago, Fuchsia excorticata, Alectryon excelsus, Pseudopanax arboreum, Myrsine salicina, and Coriaria arborea are now rare or localised and of much less consequence in the diet.     

Fleshy fruits of indigenous and adventive plants in the diet of birds in forest remnants, Nelson, New Zealand

The relationship between fleshy-fruited indigenous species and adventive weeds in the diet of 500 mist-netted birds was studied in forest remnants of differing size and degree of modification. Fruit abundance Peaked in March and April, and most fruit was either red/orange or purple/black. The physical parameters of adventive and indigenous fruits were not significantly different. Six of the 15 passerine species netted are frugivores, and of those netted 77% had eaten fruit. They were divisible into three groups: endemic (bellbirds, Anthornis melanura; tuis, Prosthemadera novaeseelandiae), non-endemic but indigenous (silvereyes, Zosterops lateralis), and adventive (blackbirds, Turdus merula; song thrushes, T. philomelos; starlings, Sturnus vulgaris). Bird diets varied between the groups and according to fruit availability as determined by sires and seasons. Endemic birds ate the least adventive fruit; bellbirds ate mainly Podocarpus hallii and Coprosma robusta fruits at all sites. Tuis had a varied diet, including some adventive fruits. Silvereyes ate the widest range of indigenous and adventive fruits. Blackbirds and, to a smaller extent, song thrushes ate many of the same indigenous fruits as the other bird groups, but their diet included more adventive fruits, e.g., Berberis glaucocarpa. Starlings were caught only when they fed on Sambucus nigra, but they also ate a few indigenous fruits. There was little seasonal variation in bird numbers caught. Adventive species extended the seasonal availability of fruits into winter, particularly in the forest remnant closest to a town, which had the highest proportion of adventive fruits. Several weed species distributed mainly by non-endemic and adventive birds are forming new secondary vegetation. Some have large fruit crops which generally offer little food for endemic birds. Where fruiting weeds pre-empt sites that may have been occupied by native species, they create an inferior habitat for endemic birds. However, the non-endemic and adventive birds also disperse indigenous fruits into early successional vegetation, and the importance of their seed rain for conservation of biodiversity will therefore depend on the site.     

Fruit Availability and Habitat Use by Chimpanzees in the Kalinzu Forest,Uganda: Examination of Fallback Foods

We studied seasonal change in habitat use by chimpanzees in the Kalinzu Forest, Uganda. The forest comprises various types of vegetation. For each vegetation type, we compared number of chimpanzees (per km²) that used the vegetation with fruit availability in different census periods. We estimated the number of chimpanzees by nest count and fruit availability via density of fallen fruit. The mixed mature forest contained a large amount of fruit during the high-fruiting season, but it decreased rapidly in the low-fruiting season. The number of chimpanzees also decreased in mixed mature forest in approximate proportion with fruit availability. In the Parinari-dominated mature and secondary forests, both fruit availability and number of chimpanzees were very low throughout the study. In the Musanga-dominated secondary forest, the number of chimpanzees increased toward the low-fruiting season, though the fruit availability decreased slightly. A multiple regression analysis showed that various fruits had significant effects on the number of chimpanzees during the high-fruiting season, while only Musanga leo-errerae had a significant effect during the low-fruiting season. The results suggest that the fruit of Musanga leo-errerae functions as a fallback food, and a combination of different vegetation types supports the chimpanzees in the Kalinzu Forest.     

Chimpanzee feeding ecology and fallback food use in the montane forest of Nyungwe National Park,Rwanda

Almost all primates experience seasonal fluctuations in the availability of key food sources. However, the degree to which this fluctuation impacts foraging behavior varies considerably. Eastern chimpanzees (Pan troglodytes schweinfurthii) in Nyungwe National Park, Rwanda, live in a montane forest environment characterized by lower primary productivity and resource diversity than low‐elevation forests. Little is known about chimpanzee feeding ecology in montane forests, and research to date predominantly relies on indirect methods such as fecal analyses. This study is the first to use mostly observational data to examine how seasonal food availability impacts the feeding ecology of montane forest chimpanzees. We examine seasonal changes in chimpanzee diet and fallback foods (FBFs) using instantaneous scan samples and fecal analyses, supported by inspection of feeding remains. Chimpanzee fruit abundance peaked during the major dry season, with a consequent change in chimpanzee diet reflecting the abundance and diversity of key fruit species. Terrestrial herbaceous vegetation was consumed throughout the year and is defined as a “filler” FBF. In contrast to studies conducted in lower‐elevation chimpanzee sites, figs (especially Ficus lutea) were preferred resources, flowers were consumed at seasonally high rates and the proportion of non‐fig fruits in the diet were relatively low in the current study. These divergences likely result from the comparatively low environmental diversity and productivity in higher‐elevation environments.     

Diet and Feeding Ecology of Chimpanzees (Pan troglodytes) in Bulindi, Uganda: Foraging Strategies at the Forest–Farm Interface

Wild animals increasingly inhabit human-influenced environments such as forest fragments amid agricultural systems. Dietary studies provide a means of assessing wildlife responses to anthropogenic habitat changes. Chimpanzees are specialist frugivores that consume other plant parts, e.g., fibrous pith and leaves, in greater amounts during fruit shortages. I examined the plant diet and seasonal foraging strategies of chimpanzees inhabiting small forest fragments within a cultivated landscape in Uganda. I determined diet over 13 mo via systematic fecal analysis, supplemented by direct observation and feeding trace evidence. I identified important foods and examined their role as seasonal fallbacks. Diet composition and breadth were overall species typical. Chimpanzees were highly frugivorous and the fruit component of fecal samples exceeded that of nonfruit fiber in all months. Forest fruit availability fluctuated seasonally, including a 3-mo low fruiting season, when overall fruit intake declined. During this time chimpanzees pursued a mixed strategy of increasing fiber consumption and feeding more heavily on energy-rich cultivars, including those obtained through crop raiding. The data suggest that exploiting agricultural fruits helped chimpanzees maintain a fruit-dominated diet when forest fruit was scarce. No evidence suggested this disturbed forest–farm mosaic is a food-impoverished habitat for chimpanzees overall. Nevertheless, cultivar feeding creates conflict with people and the high nutritional quality of crops is likely offset by the inherent risk associated with obtaining them. This study adds to growing evidence of ecological and behavioral adaptability of Pan troglodytes in response to anthropogenic habitat alteration. Targeted conservation of key natural foods for wildlife —particularly fallbacks— would help reduce conflicts and improve the survival prospects of threatened species sharing environments with people.     

White-lipped peccary (Tayassu pecari,Artiodactyla: Tayassuidae) diet and fruit availability in a Costa Rican rain forest

We studied fruit availability, diet and habitat use by white-lipped peccary (Tayassu pecari) in Corcovado National Park, southwest Costa Rica, from July 1996 to April 1997. The results show that the availability of important fruits for the white-lipped peccary differs between habitats and climatic seasons. Fruit availability was highest in the primary forest than secondary and coastal forest. There was a period of shortage of fruits to ends of the wet season, during which the consumption of not seasonal resources like leaves and shafts increased. The important fruits during this period of shortage were Ficus sp and Licania operculipetala. The several types of forest were used according to the fruit availability, and it was a direct relation between the consumption and the fruit availability.     

Seasonal variations in black-faced black spider monkey (Ateles chamek) habitat use and ranging behavior in a southern Amazonian tropical forest

Data are presented regarding the habitat use and ranging behavior of a spider monkey (Ateles chamek) community at Lago Caiman in northeastern Bolivia. Habitat use was driven primarily by fruit availability and distribution across the community home range. Strong seasonal variations occurred in fruit availability within all five of the floristically and phenologically distinct habitat types identified within the study site, and the spider monkeys dramatically shifted their ranging according to which habitat was richest in fleshy fruits. This use of local habitat diversity resulted in an unusually elongated shape for the home range that was otherwise typical of previous Ateles studies in terms of size. Ranging behavior was clumped and community core areas shifted seasonally across the focal community home range. Individual core areas were not relevant to the study due to dramatic community-wide shifts in ranging patterns. Day journey lengths were highly variable (460-5,690 m) and the distribution and abundance of fleshy fruit resources explained 81% of the monthly variations in mean day journey length. Keystone habitats for forest frugivores are identified and results are discussed with reference to previous studies on this genus, and the importance of considering keystone habitats and local habitat diversity within the management of forestry concessions in the region. Results are also discussed with reference to the behavioral ecology of the genus Ateles.     

Ranging patterns of Japanese macaques in the coniferous forest of Yakushima: Home range shift and travel rate

Ranging is one of the most important behavioral adaptations for coping with seasonally fluctuating food and thermal conditions. We studied the ranging patterns, in particular home range shift and travel rate of Japanese macaques (Macaca fuscata) in the coniferous forest of Yakushima by tracking a group for 17 months. We also supplemented our data with records collected every August over a 5-year annual census. The macaque group used the eastern part of their home range from May to September and the western part during the rest of the year. The eastern part of the home range was largely primary forest in the national park, and the altitude was higher than in the western part. When they used the western part, the macaques ate more herbs and fruits from small-sized trees, the availability of which was higher in the logged forest. This east–west home range shift occurred repeatedly over multiple years. A neighboring group occupied the western part of the focal group's home range in summer, which the focal group did not use in that season. Both temperature and diet affected seasonal changes in the monthly average travel rate. Animals need more energy for thermoregulation when the temperature is low, so the macaques decreased their ranging efforts to save energy at times of low temperature. They increased their ranging distance to eat fungi, since their encounters with this food would increase with the total distance walked. They also increased their travel rate when eating flowers, which had lower food patch (tree) density than other foods such as fruits. The data supported the hypothesis that the macaques capitalize on habitat heterogeneity in a seasonally fluctuating habitat by shifting their home range and modifying their travel rate.     

Northern pigtailed macaques rely on old growth plantations to offset low fruit availability in a degraded forest fragment

Space-use and foraging strategies are important facets to consider in regard to the ecology and conservation of primates. For this study, we documented movement, ranging, and foraging patterns of northern pigtailed macaques (Macaca leonina) for 14 months in a degraded habitat with old growth Acacia and Eucalyptus plantations at the Sakaerat Biosphere Reserve in northeastern Thailand. We used hidden Markov models and characteristic hull polygons to analyze these patterns in regard to fruit availability. Macaques' home range (HR) was 599 ha and spanned through a natural dry-evergreen forest (DEF), and plantation forest. Our results showed that active foraging increased with higher fruit availability in DEF. Macaques changed to a less continuous behavioral state during periods of lower fruit availability in DEF, repeatedly moving from foraging to transiting behavior, while extending their HR further into plantation forest and surrounding edge areas. Concomitantly, macaques shifted their diet from fleshy to dry fruit such as the introduced Acacia species. Our results showed that the diet and movement ecology adaptations of northern pigtailed macaques were largely dependent on availability of native fruits, and reflected a “high-cost, high-yield” foraging strategy when fresh food was scarce and dry fruit was available in plantation forest. Conversely, wild-feeding northern pigtailed macaque populations inhabiting pristine habitat approached a “low-cost, low-yield” foraging strategy. Our results outline the effects of habitat degradation on foraging strategies and show how a flexible species can cope with its nutritional requirements.     

Feeding ecology of western lowland gorillas in the Nouabalé-Ndoki National Park,Congo

The feeding ecology of western lowland gorillas (Gorilla gorilla gorilla) living in the Nouabalé-Ndoki National Park, northern Congo, was surveyed for one full year. This is the first record to make clear the seasonal changes in the feeding habits of gorillas in a whole year, living in the primary lowland forest almost completely undisturbed. Fecal contents, feeding traces, and direct observation were analyzed with reference to a fruit availability survey. Although the gorillas fed largely on fruits in the forest, their basic diet was fibrous parts of plants, including shoots, young leaves, and bark. Terrestrial herbaceous vegetation, such as monocotyledons of the Marantaceae and aquatic herbs having much protein content and minerals, were frequently eaten even in the fruiting season. As these highly nutritious fibrous foods were superabundant all year, the major foods of the Ndoki gorillas seemed to be those plants. However, they selected fruits as their alternative food resources in the fruiting season. Gorillas foraged on many fruit species, while showing strong preferences for some particular species. The swamp forest, including marshy grasslands, was an important and regular habitat for the Ndoki gorillas.     

Seed retention times in the New Zealand pigeon,

We offered ripe fruits of tawa (Beilschmiedia tawa), taraire (B. tarairi), and pūriri (Vitex lucens) to captive New Zealand pigeons (Hemiphaga novaeseelandiae) and recorded seed retention times. We also recorded seed retention times while radio-tracking wild pigeons in Taranaki and Canterbury. We report wild pigeon retention times for tawa, pūriri, miro (Prumnopitys ferruginea), fivefinger (Pseudopanax arboreus), and kahikatea (Dacrycarpus dacrydioides) seeds. Where data were available for the same plant species from wild and captive pigeons, retention times were similar. Seed retention time differed significantly among fruit species, and was positively related to seed mass. Mean retention times ranged from 37-45 min for the two smallest-seeded species (fivefinger and kahikatea) up to 109-181 min for the three largest species (pūriri, taraire, and tawa). We also report the second published instance of regurgitation by the New Zealand pigeon.     

The diet of the North Island kaka (

Food of the North Island kaka (Nestor meridionalis septentrionalis) on Kapiti Island was identified while quantifying the foraging activity of nine radio-tagged birds from March 1991 to January 1992. Additional food types were identified by opportunistic observation of feeding birds and qualitative examination of nestling faeces. A diverse range of food was taken, including wood-boring invertebrates, scale insects, seeds, nectar or pollen, fruits, and sap. Radio-tagged birds foraged predominantly for invertebrates over most of the year, but hinau (Elaeocarpus dentatus) seed, five-finger (Pseudopanax arboreus) nectar or pollen and tawa (Beilschmiedia tawa) seed were seasonally important food types. Most of the plant food taken by kaka on Kapiti is known to be eaten, or otherwise reduced in abundance, by Australian brushtail possums (Trichosurus vulpecula), a widespread potential competitor that has been eradicated from Kapiti. Annual variation in the abundance of important plant food types may explain variation in the breeding intensity of kaka on Kapiti Island.     

Characteristics and behaviour of brushtail possums initially moving into a depopulated area

Brushtail possums are controlled extensively in New Zealand because they are a livestock disease vector and have an impact on native biodiversity. Reinvasion of controlled areas and subsequent population recovery is a significant management problem but little attention has been paid to what influences the settlement of possums in depopulated areas. To address this gap we trapped possums out of an area of about 24?ha in native podocarp–hardwood forest and studied reinvasion and settlement in the central c. 14?ha over 22 months. Most new possums were young males, but adults were also trapped. Many of the new possums caught on the study site post-depopulation did not settle there, most likely because they continued to disperse, but some may have returned to their ranges nearby or were residents with a very low probability of capture. This finding highlights the need for better information about the origins and settlement of possums in depopulated areas to improve management of population recovery and long-term sustained control of possums.     

Food resources of the wild Barbary macaque (Macaca sylvanus) in high-altitude fir forest, Ghomaran Rif, Morocco

A small geographically isolated population of the Barbary macaque inhabits a high-altitude fir forest habitat ( Abies pinsapo ) in the Ghomaran region of the Rif mountains of northern Morocco. The climate of this region is Mediterranean, but the altitude (1600–2100 m) causes winters to be cold (as low as -8.0 C) with snow occurring from November to May (snowfall as deep as 1.5 m). The primary winter feeding adaptation is the ability to ingest high quantities of fir foliage; in spring, the macaques took a high diversity of leafy food items from all vegetation layers; in summer, the macaques foraged terrestrially for a high diversity of food items including seeds, small fruits, bulbous geophytes, and animal foods (including tadpoles from small streams); in autumn, the macaques returned to arboreal foraging, primarily feeding on oak acorns ( Quercus ilex ), fir seeds and yew fruit ( Taxus baccata ). The macaques were capable of ingesting 100 of 195 (51%) of all identified plant species in the region, although during the four-month winter, the macaques only averaged 12.5 common food items. A comparison of the study area with the prime habitat of the Barbary macaque-the high-altitude cedar forests of the Moroccan Moyen Atlas-indicates that climate and vegetation physiognomy are highly similar in both regions. Correspondingly, there is a high degree of similarity in macaque diet in both regions in terms of feeding behaviour by season, food diversity and specific feeding techniques. In the Ghomara, the winter feeding adaptation of fir foliage eating parallels that of the Barbary macaque in cedar forest (winter foraging for cedar foliage). This enables the Barbary macaque to exploit the Ghomaran fir forest habitat during the cold, snowy winters much the same as it does cedar forest habitat throughout a major portion of its geographical range.     

Feeding Ecology of Cross River Gorillas (Gorilla gorilla diehli) at Mawambi Hills: The Influence of Resource Seasonality

Determining the composition of primate diet and identifying factors that affect food choice are important in understanding habitat requirements of primates and designing conservation plans. We studied the diet of Cross River gorillas (Gorilla gorilla diehli) in relation to availability of food resources, in a semideciduous lowland forest site (Mawambi Hills) in Cameroon, from November 2009 to September 2011. Based on 109 d of feeding trail data, 203 fecal samples, and 22 mo of phenological monitoring, we determined that gorillas consumed a total of 242 food items, including 240 plant items from 186 species and 55 taxonomic families. Mawambi gorillas diversified fruit consumption when fruit availability increased, and consumed more fibrous foods (pith, leaf, bark) during times of fruit scarcity, consistent with results of other gorilla studies. However, fruit availability was not related to rainfall, and the period of fruit scarcity was more pronounced at Mawambi than at other gorilla study sites, due to a single long dry season and extreme rainfall at the end of the rainy season that delayed fruit production and ripening. We found no relationship between the daily path length of the gorillas and fruit consumption. We found feeding habits of Mawambi gorillas to be notably similar to those of a population of Cross River gorillas at Afi Mountain, Nigeria, although subtle differences existed, possibly due to site-specific differences in forest composition and altitude. At both sites the liana Landolphia spp. was the single most important food species: the leaves are a staple and the fruits are consumed during periods of fruit scarcity. Snails and maggots were consumed but we observed no further faunivory. We suggest that tree leaves and lianas are important fallback food sources in the gorilla diet in seasonally dry forests.     

Influences of seasonal flooding on macroinvertebrate abundance in wetland habitats

SUMMARY. 1. We studied the effects of seasonal flooding on macro-invertebrate abundance by manipulating water regime and detrital level within three contiguous experimental marshes in Manitoba, Canada, over 2 years. One area was seasonally flooded (standing water present through midsummer) with emergent vegetation left undisturbed throughout the study, one was semipermanently flooded (standing water present through the ice-free season) with the vegetation left undisturbed, and one was seasonally flooded with the vegetation harvested at the end of the first summer.
2. Abundances of frequent macroinvertebrate taxa were compared between the seasonally flooded-undisturbed treatment area and each of the other areas.
3. Densities of total invertebrates and of the dominant taxa (Cladocera, Ostracoda and Culicidae) were reduced dramatically by a year of semipermanent flooding, despite high levels of paniculate organic food resources and low populations of predators. Densities were not reduced by lowering the availability of detritus under seasonally flooded conditions.
4. Taxa unaffected by water regime included Dytiscidae, Corixidae, Chironomidae, Ceratopogonidae and Ephydridae.
5. Semi-permanent flooding may have eliminated environmental cues necessary for oviposition, embryonic development and hatch among dominant taxa. High invertebrate densities in temporary waters may be more dependent upon life history traits of resident fauna than upon habitat features such as food availability or predation pressure.