Abstrack Resemcb on fragmented ecosystems bas focused mostly on tbe biogeograpbic consequences of tbe creation of habitat "islands" of d i f f m t s i z e and bas p v f d e d little of practical value to managers H o m , ecosystem fragmentation causes large changes in tbepbysfcal environment as well as biogeograpbic changes Fragmentation generally msults in a landscape that consists of remnant areas of native vegetation surrounded by a mdrlx of agricultural or otber developed land As a mu14 fluxes of radiation, momentum (La, wind), water, and nutrients clcros~ tbe landsare altered significantly. Tbese in turn can haw important influences on tbe biota witbin remnant are-especially at or near tbe edge between tbe remnant and tbe surrounding matrix Tbe isolatfon of remnant areas by clearing also bas important consequences for tbe biota These consequences vary with tbe time since isolatioq distance from otber remnants, and d e p of connectivity witb otber remnants Tbe influences of pbysical and biogeographic changes are modified by tbe size, sbape, and p i t i o n in tbe landscape of individual remnanQ witb larger remnants being less aduwsely affected by tbejhapaentation process @vtuamicr Resumen. La inwstigaci6n sobre 10s ecosistemasfragmentados se ba e n f d principlmente en las c o n s~i a s biogeograficas de la maci6n de "islas" de bdbitat de diferentes tammios y ha s & de muy poco valorprdctico para 10s m a r w j h s del mcurso. Como quiera que seq la fragmenkui6n de 10s ecosistemas causa grandes cambios en el medio ambiente fkico asi como en el ambito biogeografica La fragmentaci6n resulta generalmente en terrenos que consisten de areas remanentes de vegetacidn ruativa r o d e de una mat& de tierras agricolas u otras formas de us0 de la tima Como un resultado & estq el flujo de la radiaci6n, del momentum (eJ el viento), del agua y de 10s nutrientes a t r a h de la tierra son alterados significativatnente. Esto en su turn, puerle influencim e la biota & r a m de kas amas remanentes, especialmente en o cerca de 10s limites entre 10s remanentes y la matrix que 10s &a El aislamiento de las h a s remanentespor la tala tambikr tiene imporkmtes consecuenciaspara la biota y estas consecuetacias vmlan con, el tiempo desde el momento del aislamientq la distancia basta 10s ohas remanentes y el grad0 de coneccidn entre ella La influencia de 10s cambios frSic0s y biogeogrdficos es modiJicadapor el tamatio, la fonna y la posici6n en el t m de rpmanentes indioiduales siendo 10s remanentes gmndes 10s menos afecWos adwmamante por el proceso de flagmentaci6n La didmica de las &tws remanmtes son dirigidas 18 Conservation Biology Volume 5, No. 1, M v c h 1991 S a u n d m et al. Consequences of Rqgmenpzp'on 19of remnant areas me predominantly driven by factors arising in tbe smunding krndscu#~e Management oJ and research on, fiagmented ecosystems sbould be directed at understanding and controlling tbese external influences as mu& as at tbe biota of tbe remnants themselves Tbere is a strong need to develop an integrated appmach to l...

The management of landscapes for biological conservation and ecologically sustainable natural resource use are crucial global issues. Research for over two decades has resulted in a large literature, yet there is little consensus on the applicability or even the existence of general principles or broad considerations that could guide landscape conservation. We assess six major themes in the ecology and conservation of landscapes. We identify 13 important issues that need to be considered in developing approaches to landscape conservation. They include recognizing the importance of landscape mosaics (including the integration of terrestrial and aquatic areas), recognizing interactions between vegetation cover and vegetation configuration, using an appropriate landscape conceptual model, maintaining the capacity to recover from disturbance and managing landscapes in an adaptive framework. These considerations are influenced by landscape context, species assemblages and management goals and do not translate directly into on-the-ground management guidelines but they should be recognized by researchers and resource managers when developing guidelines for specific cases. Two crucial overarching issues are: (i) a clearly articulated vision for landscape conservation and (ii) quantifiable objectives that offer unambiguous signposts for measuring progress.

In a review of landscape-scale empirical studies, Fahrig (2017a) found that ecological responses to habitat fragmentation per se (fragmentation independent of habitat amount) were usually non-significant (> 70% of responses) and that 76% of significant relationships were positive, with species abundance, occurrence, richness, and other response variables increasing with habitat fragmentation per se. Fahrig concluded that to date there is no empirical evidence supporting the widespread assumption that a group of small habitat patches generally has lower ecological value than large patches of the same total area. Fletcher et al.(2018) dispute this conclusion, arguing that the literature to date indicates generally negative ecological effects of habitat fragmentation per se. They base their argument largely on extrapolation from patchscale patterns and mechanisms (effects of patch size and isolation, and edge effects) to landscape-scale effects of habitat fragmentation. We argue that such extrapolation is unreliable because: (1) it ignores other mechanisms, especially those acting at landscape scales (e.g., increased habitat diversity, spreading of risk, landscape complementation) that can counteract effects of the documented patch-scale mechanisms; and (2) extrapolation of a small-scale mechanism to a large-scale pattern is not evidence of that pattern but, rather a prediction that must be tested at the larger scale. Such tests were the subject of Fahrig's review. We find no support for Fletcher et al.'s claim that biases in Fahrig's review would alter its conclusions. We encourage further landscape-scale empirical studies of effects of habitat fragmentation per se, and research aimed at uncovering the mechanisms that underlie positive fragmentation effects.

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Summary The breeding biology of the short‐billed form of the White‐tailed Black Cockatoo was studied at two main study areas, Coomallo Creek, an area with large tracts of uncleared lands, and Manmanning, an area of extensive clearing with little native vegetation remaining. The study was based on individually marked birds. The actions of females selecting and preparing their nest hollow ensured that other females were kept away from the area of that nest, resulting in nests being spaced out through the study areas. Eggs were laid between July and November with birds at Manmanning starting about four weeks after those at Coomallo Creek. Clutch size was a maximum of two and incubation took 28–29 days. Hatching success was higher for two‐egg clutches than for one‐egg clutches. There were no differences between fledging success for one‐egg or two‐egg clutches at either area, but fledging success at Manmanning was lower than that of Coomallo Creek. Rates of growth for weight and length of folded left wing were calculated for nestlings from both areas. These rates of growth were compared within areas between years and between areas within years. There were differences in rates of growth of nestlings from Coomallo Creek compared with those from Manmanning and these differences were related to shortages of food at Manmanning. The annual survival of tagged adults was calculated at 61–69% and that of juveniles over the first 12 months after fledging at 15%. The survival figures for adults seemed too low and it is suggested that the wearing of wing‐tags may place the individual at a selective disadvantage compared with an untagged individual.

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